Merge branch 'eugenp:master' into danielmcnally285_return_first_non_null

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/ContextSpecificDeserializationFilterFactory.java

@@ -0,0 +1,47 @@
+package com.baeldung.deserializationfilters;
+
+import java.io.ObjectInputFilter;
+import java.util.function.BinaryOperator;
+
+import com.baeldung.deserializationfilters.service.DeserializationService;
+import com.baeldung.deserializationfilters.service.LimitedArrayService;
+import com.baeldung.deserializationfilters.service.LowDepthService;
+import com.baeldung.deserializationfilters.service.SmallObjectService;
+import com.baeldung.deserializationfilters.utils.FilterUtils;
+
+public class ContextSpecificDeserializationFilterFactory implements BinaryOperator<ObjectInputFilter> {
+
+    @Override
+    public ObjectInputFilter apply(ObjectInputFilter current, ObjectInputFilter next) {
+        if (current == null) {
+            Class<?> caller = findInStack(DeserializationService.class);
+
+            if (caller == null) {
+                current = FilterUtils.fallbackFilter();
+            } else if (caller.equals(SmallObjectService.class)) {
+                current = FilterUtils.safeSizeFilter(190);
+            } else if (caller.equals(LowDepthService.class)) {
+                current = FilterUtils.safeDepthFilter(2);
+            } else if (caller.equals(LimitedArrayService.class)) {
+                current = FilterUtils.safeArrayFilter(3);
+            }
+        }
+
+        return ObjectInputFilter.merge(current, next);
+    }
+
+    private static Class<?> findInStack(Class<?> superType) {
+        for (StackTraceElement element : Thread.currentThread()
+            .getStackTrace()) {
+            try {
+                Class<?> subType = Class.forName(element.getClassName());
+                if (superType.isAssignableFrom(subType)) {
+                    return subType;
+                }
+            } catch (ClassNotFoundException e) {
+                return null;
+            }
+        }
+        return null;
+    }
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/pojo/ContextSpecific.java

@@ -0,0 +1,7 @@
+package com.baeldung.deserializationfilters.pojo;
+
+import java.io.Serializable;
+
+public interface ContextSpecific extends Serializable {
+
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/pojo/NestedSample.java

@@ -0,0 +1,19 @@
+package com.baeldung.deserializationfilters.pojo;
+
+public class NestedSample implements ContextSpecific {
+    private static final long serialVersionUID = 1L;
+
+    private Sample optional;
+
+    public NestedSample(Sample optional) {
+        this.optional = optional;
+    }
+
+    public Sample getOptional() {
+        return optional;
+    }
+
+    public void setOptional(Sample optional) {
+        this.optional = optional;
+    }
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/pojo/Sample.java

@@ -0,0 +1,61 @@
+package com.baeldung.deserializationfilters.pojo;
+
+public class Sample implements ContextSpecific, Comparable<Sample> {
+    private static final long serialVersionUID = 1L;
+
+    private int[] array;
+    private String name;
+    private NestedSample nested;
+
+    public Sample(String name) {
+        this.name = name;
+    }
+
+    public Sample(int[] array) {
+        this.array = array;
+    }
+
+    public Sample(NestedSample nested) {
+        this.nested = nested;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int[] getArray() {
+        return array;
+    }
+
+    public void setArray(int[] array) {
+        this.array = array;
+    }
+
+    public NestedSample getNested() {
+        return nested;
+    }
+
+    public void setNested(NestedSample nested) {
+        this.nested = nested;
+    }
+
+    @Override
+    public String toString() {
+        return name;
+    }
+
+    @Override
+    public int compareTo(Sample o) {
+        if (name == null)
+            return -1;
+
+        if (o == null || o.getName() == null)
+            return 1;
+
+        return getName().compareTo(o.getName());
+    }
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/pojo/SampleExploit.java

@@ -0,0 +1,25 @@
+package com.baeldung.deserializationfilters.pojo;
+
+public class SampleExploit extends Sample {
+    private static final long serialVersionUID = 1L;
+
+    public SampleExploit() {
+        super("exploit");
+    }
+
+    public static void maliciousCode() {
+        System.out.println("exploit executed");
+    }
+
+    @Override
+    public String toString() {
+        maliciousCode();
+        return "exploit";
+    }
+
+    @Override
+    public int compareTo(Sample o) {
+        maliciousCode();
+        return super.compareTo(o);
+    }
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/service/DeserializationService.java

@@ -0,0 +1,11 @@
+package com.baeldung.deserializationfilters.service;
+
+import java.io.InputStream;
+import java.util.Set;
+
+import com.baeldung.deserializationfilters.pojo.ContextSpecific;
+
+public interface DeserializationService {
+
+    Set<ContextSpecific> process(InputStream... inputStreams);
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/service/LimitedArrayService.java

@@ -0,0 +1,15 @@
+package com.baeldung.deserializationfilters.service;
+
+import java.io.InputStream;
+import java.util.Set;
+
+import com.baeldung.deserializationfilters.pojo.ContextSpecific;
+import com.baeldung.deserializationfilters.utils.DeserializationUtils;
+
+public class LimitedArrayService implements DeserializationService {
+
+    @Override
+    public Set<ContextSpecific> process(InputStream... inputStreams) {
+        return DeserializationUtils.deserializeIntoSet(inputStreams);
+    }
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/service/LowDepthService.java

@@ -0,0 +1,20 @@
+package com.baeldung.deserializationfilters.service;
+
+import java.io.InputStream;
+import java.io.ObjectInputFilter;
+import java.util.Set;
+
+import com.baeldung.deserializationfilters.pojo.ContextSpecific;
+import com.baeldung.deserializationfilters.utils.DeserializationUtils;
+
+public class LowDepthService implements DeserializationService {
+
+    public Set<ContextSpecific> process(ObjectInputFilter filter, InputStream... inputStreams) {
+        return DeserializationUtils.deserializeIntoSet(filter, inputStreams);
+    }
+
+    @Override
+    public Set<ContextSpecific> process(InputStream... inputStreams) {
+        return process(null, inputStreams);
+    }
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/service/SmallObjectService.java

@@ -0,0 +1,15 @@
+package com.baeldung.deserializationfilters.service;
+
+import java.io.InputStream;
+import java.util.Set;
+
+import com.baeldung.deserializationfilters.pojo.ContextSpecific;
+import com.baeldung.deserializationfilters.utils.DeserializationUtils;
+
+public class SmallObjectService implements DeserializationService {
+
+    @Override
+    public Set<ContextSpecific> process(InputStream... inputStreams) {
+        return DeserializationUtils.deserializeIntoSet(inputStreams);
+    }
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/utils/DeserializationUtils.java

@@ -0,0 +1,50 @@
+package com.baeldung.deserializationfilters.utils;
+
+import java.io.InputStream;
+import java.io.InvalidClassException;
+import java.io.ObjectInputFilter;
+import java.io.ObjectInputStream;
+import java.util.Set;
+import java.util.TreeSet;
+
+import com.baeldung.deserializationfilters.pojo.ContextSpecific;
+
+public class DeserializationUtils {
+    private DeserializationUtils() {
+    }
+
+    public static Object deserialize(InputStream inStream) {
+        return deserialize(inStream, null);
+    }
+
+    public static Object deserialize(InputStream inStream, ObjectInputFilter filter) {
+        try (ObjectInputStream in = new ObjectInputStream(inStream)) {
+            if (filter != null) {
+                in.setObjectInputFilter(filter);
+            }
+            return in.readObject();
+        } catch (InvalidClassException e) {
+            return null;
+        } catch (Throwable e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    public static Set<ContextSpecific> deserializeIntoSet(InputStream... inputStreams) {
+        return deserializeIntoSet(null, inputStreams);
+    }
+
+    public static Set<ContextSpecific> deserializeIntoSet(ObjectInputFilter filter, InputStream... inputStreams) {
+        Set<ContextSpecific> set = new TreeSet<>();
+
+        for (InputStream inputStream : inputStreams) {
+            Object object = deserialize(inputStream, filter);
+            if (object != null) {
+                set.add((ContextSpecific) object);
+            }
+        }
+
+        return set;
+    }
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/utils/FilterUtils.java

@@ -0,0 +1,32 @@
+package com.baeldung.deserializationfilters.utils;
+
+import java.io.ObjectInputFilter;
+
+public class FilterUtils {
+
+    private static final String DEFAULT_PACKAGE_PATTERN = "java.base/*;!*";
+    private static final String POJO_PACKAGE = "com.baeldung.deserializationfilters.pojo";
+
+    private FilterUtils() {
+    }
+
+    private static ObjectInputFilter baseFilter(String parameter, int max) {
+        return ObjectInputFilter.Config.createFilter(String.format("%s=%d;%s.**;%s", parameter, max, POJO_PACKAGE, DEFAULT_PACKAGE_PATTERN));
+    }
+
+    public static ObjectInputFilter fallbackFilter() {
+        return ObjectInputFilter.Config.createFilter(String.format("%s", DEFAULT_PACKAGE_PATTERN));
+    }
+
+    public static ObjectInputFilter safeSizeFilter(int max) {
+        return baseFilter("maxbytes", max);
+    }
+
+    public static ObjectInputFilter safeArrayFilter(int max) {
+        return baseFilter("maxarray", max);
+    }
+
+    public static ObjectInputFilter safeDepthFilter(int max) {
+        return baseFilter("maxdepth", max);
+    }
+}

core-java-modules/core-java-17/src/main/java/com/baeldung/deserializationfilters/utils/SerializationUtils.java

@@ -0,0 +1,17 @@
+package com.baeldung.deserializationfilters.utils;
+
+import java.io.IOException;
+import java.io.ObjectOutputStream;
+import java.io.OutputStream;
+
+public class SerializationUtils {
+
+    private SerializationUtils() {
+    }
+
+    public static void serialize(Object object, OutputStream outStream) throws IOException {
+        try (ObjectOutputStream objStream = new ObjectOutputStream(outStream)) {
+            objStream.writeObject(object);
+        }
+    }
+}

core-java-modules/core-java-17/src/test/java/com/baeldung/deserializationfilters/ContextSpecificDeserializationFilterIntegrationTest.java

@@ -0,0 +1,119 @@
+package com.baeldung.deserializationfilters;
+
+import static org.junit.Assert.assertNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputFilter;
+import java.util.Set;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.deserializationfilters.pojo.ContextSpecific;
+import com.baeldung.deserializationfilters.pojo.NestedSample;
+import com.baeldung.deserializationfilters.pojo.Sample;
+import com.baeldung.deserializationfilters.pojo.SampleExploit;
+import com.baeldung.deserializationfilters.service.LimitedArrayService;
+import com.baeldung.deserializationfilters.service.LowDepthService;
+import com.baeldung.deserializationfilters.service.SmallObjectService;
+import com.baeldung.deserializationfilters.utils.DeserializationUtils;
+import com.baeldung.deserializationfilters.utils.FilterUtils;
+import com.baeldung.deserializationfilters.utils.SerializationUtils;
+
+public class ContextSpecificDeserializationFilterIntegrationTest {
+
+    private static ByteArrayOutputStream serialSampleA = new ByteArrayOutputStream();
+    private static ByteArrayOutputStream serialBigSampleA = new ByteArrayOutputStream();
+
+    private static ByteArrayOutputStream serialSampleB = new ByteArrayOutputStream();
+    private static ByteArrayOutputStream serialBigSampleB = new ByteArrayOutputStream();
+
+    private static ByteArrayOutputStream serialSampleC = new ByteArrayOutputStream();
+    private static ByteArrayOutputStream serialBigSampleC = new ByteArrayOutputStream();
+
+    private static ByteArrayInputStream bytes(ByteArrayOutputStream stream) {
+        return new ByteArrayInputStream(stream.toByteArray());
+    }
+
+    @BeforeAll
+    static void setup() throws IOException {
+        ObjectInputFilter.Config.setSerialFilterFactory(new ContextSpecificDeserializationFilterFactory());
+
+        SerializationUtils.serialize(new Sample("simple"), serialSampleA);
+        SerializationUtils.serialize(new SampleExploit(), serialBigSampleA);
+
+        SerializationUtils.serialize(new Sample(new int[] { 1, 2, 3 }), serialSampleB);
+        SerializationUtils.serialize(new Sample(new int[] { 1, 2, 3, 4, 5, 6 }), serialBigSampleB);
+
+        SerializationUtils.serialize(new Sample(new NestedSample(null)), serialSampleC);
+        SerializationUtils.serialize(new Sample(new NestedSample(new Sample("deep"))), serialBigSampleC);
+    }
+
+    @Test
+    void whenSmallObjectContext_thenCorrectFilterApplied() {
+        Set<ContextSpecific> result = new SmallObjectService().process( //
+            bytes(serialSampleA), //
+            bytes(serialBigSampleA));
+
+        assertEquals(1, result.size());
+        assertEquals("simple", ((Sample) result.iterator()
+            .next()).getName());
+    }
+
+    @Test
+    void whenLimitedArrayContext_thenCorrectFilterApplied() {
+        Set<ContextSpecific> result = new LimitedArrayService().process( //
+            bytes(serialSampleB), //
+            bytes(serialBigSampleB));
+
+        assertEquals(1, result.size());
+    }
+
+    @Test
+    void whenLowDepthContext_thenCorrectFilterApplied() {
+        Set<ContextSpecific> result = new LowDepthService().process( //
+            bytes(serialSampleC), //
+            bytes(serialBigSampleC));
+
+        assertEquals(1, result.size());
+    }
+
+    @Test
+    void givenExtraFilter_whenCombinedContext_thenMergedFiltersApplied() {
+        Set<ContextSpecific> result = new LowDepthService().process( //
+            FilterUtils.safeSizeFilter(190), //
+            bytes(serialSampleA), //
+            bytes(serialBigSampleA), //
+            bytes(serialSampleC), //
+            bytes(serialBigSampleC));
+
+        assertEquals(1, result.size());
+        assertEquals("simple", ((Sample) result.iterator()
+            .next()).getName());
+    }
+
+    @Test
+    void givenFallbackContext_whenUsingBaseClasses_thenRestrictiveFilterApplied() throws IOException {
+        String a = new String("a");
+        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
+        SerializationUtils.serialize(a, outStream);
+
+        String deserializedA = (String) DeserializationUtils.deserialize(bytes(outStream));
+
+        assertEquals(a, deserializedA);
+    }
+
+    @Test
+    void givenFallbackContext_whenUsingAppClasses_thenRejected() throws IOException {
+        Sample a = new Sample("a");
+        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
+        SerializationUtils.serialize(a, outStream);
+
+        Sample deserializedA = (Sample) DeserializationUtils.deserialize(bytes(outStream));
+
+        assertNull(deserializedA);
+    }
+}

core-java-modules/core-java-17/src/test/java/com/baeldung/sealed/classes/VehicleUnitTest.java

@@ -18,19 +18,19 @@ public class VehicleUnitTest {
     }
 
     @Test
-    public void givenCar_whenUsingReflectionAPI_thenSuperClassIsSealed() {
+    public void givenCar_whenUsingReflectionAPI_thenSuperClassIsSealed() throws ClassNotFoundException {
         Assertions.assertThat(car.getClass().isSealed()).isEqualTo(false);
         Assertions.assertThat(car.getClass().getSuperclass().isSealed()).isEqualTo(true);
         Assertions.assertThat(car.getClass().getSuperclass().getPermittedSubclasses())
-                .contains(ClassDesc.of(car.getClass().getCanonicalName()));
+                .contains(Class.forName(car.getClass().getCanonicalName()));
     }
 
     @Test
-    public void givenTruck_whenUsingReflectionAPI_thenSuperClassIsSealed() {
+    public void givenTruck_whenUsingReflectionAPI_thenSuperClassIsSealed() throws ClassNotFoundException {
         Assertions.assertThat(truck.getClass().isSealed()).isEqualTo(false);
         Assertions.assertThat(truck.getClass().getSuperclass().isSealed()).isEqualTo(true);
         Assertions.assertThat(truck.getClass().getSuperclass().getPermittedSubclasses())
-                .contains(ClassDesc.of(truck.getClass().getCanonicalName()));
+                .contains(Class.forName(truck.getClass().getCanonicalName()));
     }
 
     @Test

core-java-modules/core-java-17/src/test/java/com/baeldung/sealed/records/VehicleUnitTest.java

@@ -18,19 +18,19 @@ public class VehicleUnitTest {
     }
 
     @Test
-    public void givenCar_whenUsingReflectionAPI_thenInterfaceIsSealed() {
+    public void givenCar_whenUsingReflectionAPI_thenInterfaceIsSealed() throws ClassNotFoundException {
         Assertions.assertThat(car.getClass().isSealed()).isEqualTo(false);
         Assertions.assertThat(car.getClass().getInterfaces()[0].isSealed()).isEqualTo(true);
-        Assertions.assertThat(car.getClass().getInterfaces()[0].permittedSubclasses())
-                .contains(ClassDesc.of(car.getClass().getCanonicalName()));
+        Assertions.assertThat(car.getClass().getInterfaces()[0].getPermittedSubclasses())
+                .contains(Class.forName(car.getClass().getCanonicalName()));
     }
 
     @Test
-    public void givenTruck_whenUsingReflectionAPI_thenInterfaceIsSealed() {
+    public void givenTruck_whenUsingReflectionAPI_thenInterfaceIsSealed() throws ClassNotFoundException {
         Assertions.assertThat(truck.getClass().isSealed()).isEqualTo(false);
         Assertions.assertThat(truck.getClass().getInterfaces()[0].isSealed()).isEqualTo(true);
-        Assertions.assertThat(truck.getClass().getInterfaces()[0].permittedSubclasses())
-                .contains(ClassDesc.of(truck.getClass().getCanonicalName()));
+        Assertions.assertThat(truck.getClass().getInterfaces()[0].getPermittedSubclasses())
+                .contains(Class.forName(truck.getClass().getCanonicalName()));
     }
 
     @Test

core-java-modules/core-java-8-datetime-2/README.md

@@ -6,4 +6,5 @@
 - [How Many Days Are There in a Particular Month of a Given Year?](https://www.baeldung.com/days-particular-month-given-year)
 - [Difference Between Instant and LocalDateTime](https://www.baeldung.com/java-instant-vs-localdatetime)
 - [Add Minutes to a Time String in Java](https://www.baeldung.com/java-string-time-add-mins)
+- [Round the Date in Java](https://www.baeldung.com/java-round-the-date)
 - [[<-- Prev]](/core-java-modules/core-java-datetime-java8-1)

core-java-modules/core-java-8-datetime-2/pom.xml

@@ -55,7 +55,7 @@
     <properties>
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
-        <joda-time.version>2.10</joda-time.version>
+        <joda-time.version>2.12.5</joda-time.version>
     </properties>
 
 </project>

core-java-modules/core-java-8-datetime-2/src/main/java/com/baeldung/maxdate/DateComparison.java

@@ -0,0 +1,18 @@
+package com.baeldung.maxdate;
+
+import java.util.Date;
+
+public class DateComparison {
+    public int compareTodayWithMaxDate() {
+        Date today = new Date();
+        Date maxDate = new Date(Long.MAX_VALUE);
+
+        int comparisonResult = today.compareTo(maxDate);
+        return comparisonResult;
+    }
+
+    public static void main(String[] args) {
+        DateComparison comparator = new DateComparison();
+        System.out.println(comparator.compareTodayWithMaxDate());
+    }
+}

core-java-modules/core-java-8-datetime-2/src/main/java/com/baeldung/maxdate/MaxDateDisplay.java

@@ -0,0 +1,18 @@
+package com.baeldung.maxdate;
+
+import java.util.Date;
+import java.text.SimpleDateFormat;
+
+public class MaxDateDisplay {
+    public String getMaxDateValue() {
+        Date maxDate = new Date(Long.MAX_VALUE);
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
+        return "The maximum date value in Java is: " + sdf.format(maxDate);
+    }
+
+    public static void main(String[] args) {
+        MaxDateDisplay display = new MaxDateDisplay();
+        System.out.println(display.getMaxDateValue());
+    }
+}
+

core-java-modules/core-java-8-datetime-2/src/main/java/com/baeldung/parsingDates/SimpleParseDate.java

@@ -7,7 +7,7 @@ import java.util.List;
 
 public class SimpleParseDate {
 
-    public Date parseDate(String dateString, List<String> formatStrings) {
+    public static Date parseDate(String dateString, List<String> formatStrings) {
         for (String formatString : formatStrings) {
             try {
                 return new SimpleDateFormat(formatString).parse(dateString);

core-java-modules/core-java-8-datetime-2/src/test/java/com/baeldung/maxdate/DateComparisonUnitTest.java

@@ -0,0 +1,16 @@
+package com.baeldung.maxdate;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class DateComparisonUnitTest {
+
+  @Test
+  void whenCompareTodayWithMaxDate_thenCorrectResult() {
+    DateComparison comparator = new DateComparison();
+    int result = comparator.compareTodayWithMaxDate();
+
+    assertTrue(result < 0);
+  }
+}

core-java-modules/core-java-8-datetime-2/src/test/java/com/baeldung/maxdate/MaxDateDisplayUnitTest.java

@@ -0,0 +1,18 @@
+package com.baeldung.maxdate;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class MaxDateDisplayUnitTest {
+
+  @Test
+  void whenGetMaxDate_thenCorrectResult() {
+    MaxDateDisplay display = new MaxDateDisplay();
+    String result = display.getMaxDateValue();
+    assertEquals(
+      "The maximum date value in Java is: 292278994-08-17 07:12:55.807",
+      result
+    );
+  }
+}

core-java-modules/core-java-8-datetime-2/src/test/java/com/baeldung/parsingDates/SimpleParseDateUnitTest.java

@@ -1,43 +1,41 @@
 package com.baeldung.parsingDates;
 
-import com.baeldung.parsingDates.SimpleDateTimeFormat;
-import com.baeldung.parsingDates.SimpleDateTimeFormater;
-import com.baeldung.parsingDates.SimpleDateUtils;
-import com.baeldung.parsingDates.SimpleParseDate;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
 import java.time.format.DateTimeParseException;
 import java.util.Arrays;
-import org.junit.*;
-import static org.junit.Assert.*;
+
 import org.joda.time.LocalDate;
+import org.junit.jupiter.api.Test;
 
-public class SimpleParseDateUnitTest {
+class SimpleParseDateUnitTest {
 
     @Test
-    public void whenInvalidInput_thenGettingUnexpectedResult() {
-        SimpleParseDate simpleParseDate = new SimpleParseDate();
+    void whenInvalidInput_thenGettingUnexpectedResult() {
         String date = "2022-40-40";
-        assertEquals("Sat May 10 00:00:00 UTC 2025", simpleParseDate.parseDate(date, Arrays.asList("MM/dd/yyyy", "dd.MM.yyyy", "yyyy-MM-dd")).toString());
+        assertEquals("Sat May 10 00:00:00 UTC 2025", SimpleParseDate.parseDate(date, Arrays.asList("MM/dd/yyyy", "dd.MM.yyyy", "yyyy-MM-dd"))
+            .toString());
     }
 
     @Test
-    public void whenInvalidDate_thenAssertThrows() {
-        SimpleDateTimeFormater simpleDateTimeFormater = new SimpleDateTimeFormater();
-        assertEquals(java.time.LocalDate.parse("2022-12-04"), simpleDateTimeFormater.parseDate("2022-12-04"));
-        assertThrows(DateTimeParseException.class, () -> simpleDateTimeFormater.parseDate("2022-13-04"));
+    void whenInvalidDate_thenAssertThrows() {
+        assertEquals(java.time.LocalDate.parse("2022-12-04"), SimpleDateTimeFormater.parseDate("2022-12-04"));
+        assertThrows(DateTimeParseException.class, () -> SimpleDateTimeFormater.parseDate("2022-13-04"));
     }
 
     @Test
-    public void whenDateIsCorrect_thenParseCorrect() {
-        SimpleDateUtils simpleDateUtils = new SimpleDateUtils();
-        assertNull(simpleDateUtils.parseDate("53/10/2014"));
-        assertEquals("Wed Sep 10 00:00:00 UTC 2014", simpleDateUtils.parseDate("10/09/2014").toString());
+    void whenDateIsCorrect_thenParseCorrect() {
+        assertNull(SimpleDateUtils.parseDate("53/10/2014"));
+        assertEquals("Wed Sep 10 00:00:00 UTC 2014", SimpleDateUtils.parseDate("10/09/2014")
+            .toString());
     }
 
     @Test
-    public void whenDateIsCorrect_thenResultCorrect() {
-        SimpleDateTimeFormat simpleDateTimeFormat = new SimpleDateTimeFormat();
-        assertNull(simpleDateTimeFormat.parseDate("53/10/2014"));
-        assertEquals(LocalDate.parse("2014-10-10"), simpleDateTimeFormat.parseDate("2014-10-10"));
+    void whenDateIsCorrect_thenResultCorrect() {
+        assertNull(SimpleDateTimeFormat.parseDate("53/10/2014"));
+        assertEquals(LocalDate.parse("2014-10-10"), SimpleDateTimeFormat.parseDate("2014-10-10"));
     }
 
 }

core-java-modules/core-java-8-datetime/pom.xml

@@ -56,7 +56,7 @@
     <properties>
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
-        <joda-time.version>2.10</joda-time.version>
+        <joda-time.version>2.12.5</joda-time.version>
     </properties>
 
 </project>

core-java-modules/core-java-8/src/main/java/com/baeldung/streamreduce/application/Application.java

@@ -1,62 +0,0 @@
-package com.baeldung.streamreduce.application;
-
-import com.baeldung.streamreduce.entities.User;
-import com.baeldung.streamreduce.utilities.NumberUtils;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-
-public class Application {
-
-    public static void main(String[] args) {
-        List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
-        int result1 = numbers.stream().reduce(0, (a, b) -> a + b);
-        System.out.println(result1);
-        
-        int result2 = numbers.stream().reduce(0, Integer::sum);
-        System.out.println(result2);
-
-        List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
-        String result3 = letters.stream().reduce("", (a, b) -> a + b);
-        System.out.println(result3);
-        
-        String result4 = letters.stream().reduce("", String::concat);
-        System.out.println(result4);
-
-        String result5 = letters.stream().reduce("", (a, b) -> a.toUpperCase() + b.toUpperCase());
-        System.out.println(result5);
-        
-        List<User> users = Arrays.asList(new User("John", 30), new User("Julie", 35));
-        int result6 = users.stream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
-        System.out.println(result6);
-        
-        String result7 = letters.parallelStream().reduce("", String::concat);
-        System.out.println(result7);
-        
-        int result8 = users.parallelStream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
-        System.out.println(result8);
-        
-        List<User> userList = new ArrayList<>();
-        for (int i = 0; i <= 1000000; i++) {
-            userList.add(new User("John" + i, i));
-        }
-        
-        long t1 = System.currentTimeMillis();
-        int result9 = userList.stream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
-        long t2 = System.currentTimeMillis();
-        System.out.println(result9);
-        System.out.println("Sequential stream time: " + (t2 - t1) + "ms");
-        
-        long t3 = System.currentTimeMillis();
-        int result10 = userList.parallelStream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
-        long t4 = System.currentTimeMillis();
-        System.out.println(result10);
-        System.out.println("Parallel stream time: " + (t4 - t3) + "ms");
-        
-        int result11 = NumberUtils.divideListElements(numbers, 1);
-        System.out.println(result11);
-        
-        int result12 = NumberUtils.divideListElementsWithExtractedTryCatchBlock(numbers, 0);
-        System.out.println(result12);
-    }    
-}

core-java-modules/core-java-8/src/main/java/com/baeldung/streamreduce/entities/Rating.java

@@ -1,39 +0,0 @@
-package com.baeldung.streamreduce.entities;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class Rating {
-
-    double points;
-    List<Review> reviews = new ArrayList<>();
-
-    public Rating() {}
-
-    public void add(Review review) {
-        reviews.add(review);
-        computeRating();
-    }
-
-    private double computeRating() {
-        double totalPoints = reviews.stream().map(Review::getPoints).reduce(0, Integer::sum);
-        this.points = totalPoints / reviews.size();
-        return this.points;
-    }
-
-    public static Rating average(Rating r1, Rating r2) {
-        Rating combined = new Rating();
-        combined.reviews = new ArrayList<>(r1.reviews);
-        combined.reviews.addAll(r2.reviews);
-        combined.computeRating();
-        return combined;
-    }
-
-    public double getPoints() {
-        return points;
-    }
-
-    public List<Review> getReviews() {
-        return reviews;
-    }
-}

core-java-modules/core-java-8/src/main/java/com/baeldung/streamreduce/entities/Review.java

@@ -1,28 +0,0 @@
-package com.baeldung.streamreduce.entities;
-
-public class Review {
-
-    int points;
-    String review;
-
-    public Review(int points, String review) {
-        this.points = points;
-        this.review = review;
-    }
-
-    public int getPoints() {
-        return points;
-    }
-
-    public void setPoints(int points) {
-        this.points = points;
-    }
-
-    public String getReview() {
-        return review;
-    }
-
-    public void setReview(String review) {
-        this.review = review;
-    }
-}

core-java-modules/core-java-8/src/main/java/com/baeldung/streamreduce/entities/User.java

@@ -1,30 +0,0 @@
-package com.baeldung.streamreduce.entities;
-
-public class User {
-
-    private final String name;
-    private final int age;
-    private final Rating rating = new Rating();
-
-    public User(String name, int age) {
-        this.name = name;
-        this.age = age;
-    }
-
-    public String getName() {
-        return name;
-    }
-
-    public int getAge() {
-        return age;
-    }
-
-    public Rating getRating() {
-        return rating;
-    }
-
-    @Override
-    public String toString() {
-        return "User{" + "name=" + name + ", age=" + age + '}';
-    }
-}

core-java-modules/core-java-8/src/main/java/com/baeldung/streamreduce/utilities/NumberUtils.java

@@ -1,52 +0,0 @@
-package com.baeldung.streamreduce.utilities;
-
-import java.util.List;
-import java.util.function.BiFunction;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-
-public abstract class NumberUtils {
-
-    private static final Logger LOGGER = Logger.getLogger(NumberUtils.class.getName());
-
-    public static int divideListElements(List<Integer> values, Integer divider) {
-        return values.stream()
-                .reduce(0, (a, b) -> {
-                    try {
-                        return a / divider + b / divider;
-                    } catch (ArithmeticException e) {
-                        LOGGER.log(Level.INFO, "Arithmetic Exception: Division by Zero");
-                    }
-                    return 0;
-                });
-    }
-    
-    public static int divideListElementsWithExtractedTryCatchBlock(List<Integer> values, int divider) {
-        return values.stream().reduce(0, (a, b) -> divide(a, divider) + divide(b, divider));
-    }
-    
-    public static int divideListElementsWithApplyFunctionMethod(List<Integer> values, int divider) {
-        BiFunction<Integer, Integer, Integer> division = (a, b) -> a / b;
-        return values.stream().reduce(0, (a, b) -> applyFunction(division, a, divider) + applyFunction(division, b, divider));
-    }
-    
-    private static int divide(int value, int factor) {
-        int result = 0;
-        try {
-            result = value / factor;
-        } catch (ArithmeticException e) {
-            LOGGER.log(Level.INFO, "Arithmetic Exception: Division by Zero");
-        }
-        return result;
-    }
-    
-    private static int applyFunction(BiFunction<Integer, Integer, Integer> function, int a, int b) {
-        try {
-            return function.apply(a, b);
-        }
-        catch(Exception e) {
-            LOGGER.log(Level.INFO, "Exception occurred!");
-        }
-        return 0;
-    }
-}

core-java-modules/core-java-collections-4/pom.xml

@@ -34,7 +34,6 @@
 
     <properties>
         <commons-lang.version>2.2</commons-lang.version>
-        <commons-lang3.version>3.12.0</commons-lang3.version>
     </properties>
 
 </project>

core-java-modules/core-java-collections-5/README.md

@@ -8,4 +8,5 @@
 - [Difference Between Arrays.sort() and Collections.sort()](https://www.baeldung.com/java-arrays-collections-sort-methods)
 - [Skipping the First Iteration in Java](https://www.baeldung.com/java-skip-first-iteration)
 - [Remove Elements From a Queue Using Loop](https://www.baeldung.com/java-remove-elements-queue)
+- [Intro to Vector Class in Java](https://www.baeldung.com/java-vector-guide)
 - More articles: [[<-- prev]](/core-java-modules/core-java-collections-4)

core-java-modules/core-java-collections-5/src/main/java/com/baeldung/collectionssortcomplexity/CollectionsSortTimeComplexityJMH.java

@@ -0,0 +1,60 @@
+package com.baeldung.collectionssortcomplexity;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@Fork(value = 1, warmups = 1)
+@Warmup(iterations = 5, time = 1)
+@Measurement(iterations = 5, time = 1)
+public class CollectionsSortTimeComplexityJMH {
+
+    public static void main(String[] args) throws Exception {
+        org.openjdk.jmh.Main.main(args);
+
+    }
+
+    @Benchmark
+    public void measureCollectionsSortBestCase(BestCaseBenchmarkState state) {
+        List<Integer> sortedList = new ArrayList<>(state.sortedList);
+        Collections.sort(sortedList);
+    }
+
+    @Benchmark
+    public void measureCollectionsSortAverageWorstCase(AverageWorstCaseBenchmarkState state) {
+        List<Integer> unsortedList = new ArrayList<>(state.unsortedList);
+        Collections.sort(unsortedList);
+    }
+
+    @State(Scope.Benchmark)
+    public static class BestCaseBenchmarkState {
+        List<Integer> sortedList;
+
+        @Setup(Level.Trial)
+        public void setUp() {
+            sortedList = new ArrayList<>();
+            for (int i = 1; i <= 1000000; i++) {
+                sortedList.add(i);
+            }
+        }
+    }
+
+    @State(Scope.Benchmark)
+    public static class AverageWorstCaseBenchmarkState {
+        List<Integer> unsortedList;
+
+        @Setup(Level.Trial)
+        public void setUp() {
+            unsortedList = new ArrayList<>();
+            for (int i = 1000000; i > 0; i--) {
+                unsortedList.add(i);
+            }
+        }
+    }
+
+}

core-java-modules/core-java-collections-5/src/main/java/com/baeldung/collectionssortcomplexity/CollectionsSortTimeComplexityMain.java

@@ -0,0 +1,33 @@
+package com.baeldung.collectionssortcomplexity;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public class CollectionsSortTimeComplexityMain {
+    // O(n log n) Time Complexity Example
+    public static void worstAndAverageCasesTimeComplexity() {
+        Integer[] sortedArray = {20, 21, 22, 23, 24, 25, 26, 17, 28, 29, 30, 31, 18, 19, 32, 33, 34, 27, 35};
+        List<Integer> list = Arrays.asList(sortedArray);
+        Collections.shuffle(list);
+        long startTime = System.nanoTime();
+        Collections.sort(list);
+        long endTime = System.nanoTime();
+        System.out.println("Execution Time for O(n log n): " + (endTime - startTime) + " nanoseconds");
+    }
+
+    // O(n) Time Complexity Example
+    public static void bestCaseTimeComplexity() {
+        Integer[] sortedArray = {19, 22, 19, 22, 24, 25, 17, 11, 22, 23, 28, 23, 0, 1, 12, 9, 13, 27, 15};
+        List<Integer> list = Arrays.asList(sortedArray);
+        long startTime = System.nanoTime();
+        Collections.sort(list);
+        long endTime = System.nanoTime();
+        System.out.println("Execution Time for O(n): " + (endTime - startTime) + " nanoseconds");
+    }
+
+    public static void main(String[] args) {
+        worstAndAverageCasesTimeComplexity();
+        bestCaseTimeComplexity();
+    }
+}

core-java-modules/core-java-collections-5/toarraymethod/ConvertingHashSetToArrayUnitTest.java

@@ -0,0 +1,51 @@
+package com.baeldung.toarraymethod;
+
+import org.junit.Test;
+
+import java.util.HashSet;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class ConvertingHashSetToArrayUnitTest {
+
+    @Test
+    public void givenStringHashSet_whenConvertedToArray_thenArrayContainsStringElements() {
+        HashSet<String> stringSet = new HashSet<>();
+        stringSet.add("Apple");
+        stringSet.add("Banana");
+        stringSet.add("Cherry");
+
+        // Convert the HashSet of Strings to an array of Strings
+        String[] stringArray = stringSet.toArray(new String[0]);
+
+        // Test that the array is of the correct length
+        assertEquals(3, stringArray.length);
+
+        for (String str : stringArray) {
+            assertTrue(stringSet.contains(str));
+        }
+    }
+
+    @Test
+    public void givenIntegerHashSet_whenConvertedToArray_thenArrayContainsIntegerElements() {
+        HashSet<Integer> integerSet = new HashSet<>();
+        integerSet.add(5);
+        integerSet.add(10);
+        integerSet.add(15);
+
+        // Convert the HashSet of Integers to an array of Integers
+        Integer[] integerArray = integerSet.toArray(new Integer[0]);
+
+        // Test that the array is of the correct length
+        assertEquals(3, integerArray.length);
+
+        for (Integer num : integerArray) {
+            assertTrue(integerSet.contains(num));
+        }
+
+        assertTrue(integerSet.contains(5));
+        assertTrue(integerSet.contains(10));
+        assertTrue(integerSet.contains(15));
+    }
+}

core-java-modules/core-java-collections-conversions-2/pom.xml

@@ -44,6 +44,6 @@
     <properties>
         <vavr.version>0.10.3</vavr.version>
         <java.version>11</java.version>
-        <modelmapper.version>3.1.1</modelmapper.version>
+        <modelmapper.version>3.2.0</modelmapper.version>
     </properties>
 </project>

core-java-modules/core-java-collections-conversions-2/src/test/java/com/baeldung/modelmapper/UsersListMappingUnitTest.java

@@ -1,8 +1,9 @@
 package com.baeldung.modelmapper;
 
 import org.hamcrest.Matchers;
-import org.junit.Before;
-import org.junit.Test;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.modelmapper.ModelMapper;
 import org.modelmapper.TypeMap;
 import org.modelmapper.TypeToken;
@@ -10,11 +11,10 @@ import org.modelmapper.TypeToken;
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItems;
 import static org.hamcrest.Matchers.hasProperty;
-import static org.junit.Assert.assertThat;
-
 
 /**
  * This class has test methods of mapping Integer to Character list,
@@ -22,12 +22,12 @@ import static org.junit.Assert.assertThat;
  *
  * @author Sasa Milenkovic
  */
-public class UsersListMappingUnitTest {
+class UsersListMappingUnitTest {
 
     private ModelMapper modelMapper;
     private List<User> users;
 
-    @Before
+    @BeforeEach
     public void init() {
 
         modelMapper = new ModelMapper();
@@ -35,18 +35,16 @@ public class UsersListMappingUnitTest {
         TypeMap<UserList, UserListDTO> typeMap = modelMapper.createTypeMap(UserList.class, UserListDTO.class);
 
         typeMap.addMappings(mapper -> mapper.using(new UsersListConverter())
-                .map(UserList::getUsers, UserListDTO::setUsernames));
+            .map(UserList::getUsers, UserListDTO::setUsernames));
 
-        users = new ArrayList();
+        users = new ArrayList<>();
         users.add(new User("b100", "user1", "user1@baeldung.com", "111-222", "USER"));
         users.add(new User("b101", "user2", "user2@baeldung.com", "111-333", "USER"));
         users.add(new User("b102", "user3", "user3@baeldung.com", "111-444", "ADMIN"));
-
     }
 
     @Test
-    public void whenInteger_thenMapToCharacter() {
-
+    void whenInteger_thenMapToCharacter() {
         List<Integer> integers = new ArrayList<Integer>();
 
         integers.add(1);
@@ -57,36 +55,27 @@ public class UsersListMappingUnitTest {
         }.getType());
 
         assertThat(characters, hasItems('1', '2', '3'));
-
     }
 
     @Test
-    public void givenUsersList_whenUseGenericType_thenMapToUserDTO() {
-
+    void givenUsersList_whenUseGenericType_thenMapToUserDTO() {
         // Mapping lists using custom (generic) type mapping
-
         List<UserDTO> userDtoList = MapperUtil.mapList(users, UserDTO.class);
 
-        assertThat(userDtoList, Matchers.<UserDTO>hasItem(
-                Matchers.both(hasProperty("userId", equalTo("b100")))
-                        .and(hasProperty("email", equalTo("user1@baeldung.com")))
-                        .and(hasProperty("username", equalTo("user1")))));
-
-
+        assertThat(userDtoList, Matchers.<UserDTO> hasItem(Matchers.both(hasProperty("userId", equalTo("b100")))
+            .and(hasProperty("email", equalTo("user1@baeldung.com")))
+            .and(hasProperty("username", equalTo("user1")))));
     }
 
     @Test
-    public void givenUsersList_whenUseConverter_thenMapToUsernames() {
-
+    void givenUsersList_whenUseConverter_thenMapToUsernames() {
         // Mapping lists using property mapping and converter
-
         UserList userList = new UserList();
         userList.setUsers(users);
         UserListDTO dtos = new UserListDTO();
         modelMapper.map(userList, dtos);
 
         assertThat(dtos.getUsernames(), hasItems("user1", "user2", "user3"));
-
     }
 
 }

core-java-modules/core-java-collections-list-5/pom.xml

@@ -66,7 +66,6 @@
     <properties>
         <jmh.version>1.21</jmh.version>
         <commons-lang.version>2.2</commons-lang.version>
-        <commons-lang3.version>3.12.0</commons-lang3.version>
         <gson.version>2.10.1</gson.version>
         <jackson.version>2.15.2</jackson.version>
         <org.json.version>20230618</org.json.version>

core-java-modules/core-java-collections-maps-7/README.md

@@ -1,3 +1,7 @@
-## Relevant Articles
+## Relevant Articles:
 - [Difference Between putIfAbsent() and computeIfAbsent() in Java’s Map](https://www.baeldung.com/java-map-putifabsent-computeifabsent)
+- [How to Write and Read a File with a Java HashMap](https://www.baeldung.com/how-to-write-and-read-a-file-with-a-java-hashmap/)
 - [How to Write Hashmap to CSV File](https://www.baeldung.com/java-write-hashmap-csv)
+- [How to Get First or Last Entry From a LinkedHashMap in Java](https://www.baeldung.com/java-linkedhashmap-first-last-key-value-pair)
+- [How to Write and Read a File with a Java HashMap](https://www.baeldung.com/java-hashmap-write-read-file)
+- More articles: [[<-- prev]](/core-java-modules/core-java-collections-maps-6)

core-java-modules/core-java-collections-maps-7/pom.xml

@@ -1,11 +1,15 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <artifactId>core-java-collections-maps-7</artifactId>
     <name>core-java-collections-maps-7</name>
     <packaging>jar</packaging>
+    <properties>
+        <gson.version>2.10.1</gson.version>
+        <csv.version>1.5</csv.version>
+    </properties>
 
     <parent>
         <artifactId>core-java-modules</artifactId>
@@ -13,72 +17,24 @@
         <version>0.0.1-SNAPSHOT</version>
     </parent>
 
-    <properties>
-        <spring.version>5.2.5.RELEASE</spring.version>
-    </properties>
     <dependencies>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
-            <version>2.12.4</version>
-        </dependency>
-        <dependency>
-            <groupId>org.openjdk.jmh</groupId>
-            <artifactId>jmh-core</artifactId>
-            <version>1.36</version>
+            <version>${jackson.version}</version>
         </dependency>
         <dependency>
             <groupId>com.google.code.gson</groupId>
             <artifactId>gson</artifactId>
-            <version>2.8.9</version>
-        </dependency>
-        <dependency>
-            <groupId>org.json</groupId>
-            <artifactId>json</artifactId>
-            <version>20230227</version>
-        </dependency>
-        <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <version>4.13.1</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter</artifactId>
-            <version>5.8.1</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter</artifactId>
-            <version>5.8.1</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <version>4.13.1</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter</artifactId>
-            <version>5.8.1</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <version>4.13.1</version>
-            <scope>test</scope>
+            <version>${gson.version}</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-csv</artifactId>
-            <version>1.5</version>
+            <version>${csv.version}</version>
         </dependency>
     </dependencies>
+
     <build>
         <plugins>
             <plugin>
@@ -92,5 +48,4 @@
             </plugin>
         </plugins>
     </build>
-
 </project>

core-java-modules/core-java-collections-maps-7/src/main/java/com/baeldung/map/readandwritefile/Student.java

@@ -0,0 +1,51 @@
+package com.baeldung.map.readandwritefile;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+public class Student implements Serializable {
+    private static final long serialVersionUID = 1L;
+    private String firstName;
+    private String lastName;
+
+    /** Default constructor for JSON serialization */
+    public Student() {
+
+    }
+
+    public Student(String firstName, String lastName) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        Student student = (Student) o;
+        return Objects.equals(firstName, student.firstName) && Objects.equals(lastName, student.lastName);
+    }
+
+    @Override
+    public int hashCode() {
+        return super.hashCode();
+    }
+}

core-java-modules/core-java-collections-maps-7/src/test/java/com/baeldung/map/readandwritefile/ReadAndWriteFileWithHashMapUnitTest.java

@@ -0,0 +1,135 @@
+package com.baeldung.map.readandwritefile;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.OutputStream;
+import java.lang.reflect.Type;
+import java.nio.file.Files;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+import java.util.stream.Collectors;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.gson.Gson;
+import com.google.gson.reflect.TypeToken;
+
+import org.junit.After;
+import org.junit.Test;
+import org.junit.Before;
+
+public class ReadAndWriteFileWithHashMapUnitTest {
+
+    private static final Map<Integer, Student> STUDENT_DATA = new HashMap<>();
+
+    static {
+        STUDENT_DATA.put(1234, new Student("Henry", "Winter"));
+        STUDENT_DATA.put(5678, new Student("Richard", "Papen"));
+    }
+
+    private File file;
+
+    @Before
+    public void createFile() throws IOException {
+        file = File.createTempFile("student", ".data");
+    }
+
+    @After
+    public void deleteFile() {
+        file.delete();
+    }
+
+    @Test
+    public void givenHashMap_whenWrittenAsPropertiesFile_thenReloadedMapIsIdentical() throws IOException {
+        // Given a map containing student data
+        Map<String, String> studentData = new HashMap<>();
+        studentData.put("student.firstName", "Henry");
+        studentData.put("student.lastName", "Winter");
+
+        // When converting to a Properties object and writing to a file
+        Properties props = new Properties();
+        props.putAll(studentData);
+        try (OutputStream output = Files.newOutputStream(file.toPath())) {
+            props.store(output, null);
+        }
+
+        // Then the map resulting from loading the Properties file is identical
+        Properties propsFromFile = new Properties();
+        try (InputStream input = Files.newInputStream(file.toPath())) {
+            propsFromFile.load(input);
+        }
+
+        Map<String, String> studentDataFromProps = propsFromFile.stringPropertyNames()
+            .stream()
+            .collect(Collectors.toMap(key -> key, props::getProperty));
+        assertThat(studentDataFromProps).isEqualTo(studentData);
+    }
+
+    @Test
+    public void givenHashMap_whenSerializedToFile_thenDeserializedMapIsIdentical() throws IOException, ClassNotFoundException {
+        // Given a map containing student data (STUDENT_DATA)
+
+        // When serializing the map to a file
+        try (FileOutputStream fileOutput = new FileOutputStream(file); ObjectOutputStream objectStream = new ObjectOutputStream(fileOutput)) {
+            objectStream.writeObject(STUDENT_DATA);
+        }
+
+        // Then read the file back into a map and check the contents
+        Map<Integer, Student> studentsFromFile;
+        try (FileInputStream fileReader = new FileInputStream(file); ObjectInputStream objectStream = new ObjectInputStream(fileReader)) {
+            studentsFromFile = (HashMap<Integer, Student>) objectStream.readObject();
+        }
+        assertThat(studentsFromFile).isEqualTo(STUDENT_DATA);
+    }
+
+    @Test
+    public void givenHashMap_whenSerializedToFileWithJackson_thenDeserializedMapIsIdentical() throws IOException {
+        // Given a map containing student data (STUDENT_DATA)
+
+        // When converting to JSON with Jackson and writing to a file
+        ObjectMapper mapper = new ObjectMapper();
+        try (FileOutputStream fileOutput = new FileOutputStream(file)) {
+            mapper.writeValue(fileOutput, STUDENT_DATA);
+        }
+
+        // Then deserialize the file back into a map and check that it's identical
+        Map<Integer, Student> mapFromFile;
+        try (FileInputStream fileInput = new FileInputStream(file)) {
+            // Create a TypeReference so we can deserialize the parameterized type
+            TypeReference<HashMap<Integer, Student>> mapType = new TypeReference<HashMap<Integer, Student>>() {
+            };
+            mapFromFile = mapper.readValue(fileInput, mapType);
+        }
+        assertThat(mapFromFile).isEqualTo(STUDENT_DATA);
+    }
+
+    @Test
+    public void givenHashMap_whenSerializedToFileWithGson_thenDeserializedMapIsIdentical() throws IOException {
+        // Given a map containing student data (STUDENT_DATA)
+
+        // When converting to JSON using Gson and writing to a file
+        Gson gson = new Gson();
+        try (FileWriter writer = new FileWriter(file)) {
+            gson.toJson(STUDENT_DATA, writer);
+        }
+
+        // Then deserialize the file back into a map and check that it's identical
+        Map<Integer, Student> studentsFromFile;
+        try (FileReader reader = new FileReader(file)) {
+            Type mapType = new TypeToken<HashMap<Integer, Student>>() {
+            }.getType();
+            studentsFromFile = gson.fromJson(reader, mapType);
+        }
+        assertThat(studentsFromFile).isEqualTo(STUDENT_DATA);
+    }
+}

core-java-modules/core-java-concurrency-advanced-5/src/test/java/com/baeldung/exceptions_completablefuture/CompletableFutureExceptionsHandlingUnitTest.java

@@ -0,0 +1,126 @@
+package com.baeldung.exceptions_completablefuture;
+
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.stream.Stream;
+
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class CompletableFutureExceptionsHandlingUnitTest {
+
+    @ParameterizedTest
+    @MethodSource("parametersSource_handle")
+    void whenCompletableFutureIsScheduled_thenHandleStageIsAlwaysInvoked(int radius, long expected)
+      throws ExecutionException, InterruptedException {
+        long actual = CompletableFuture
+          .supplyAsync(() -> {
+              if (radius <= 0) {
+                  throw new IllegalArgumentException("Supplied with non-positive radius '%d'");
+              }
+              return Math.round(Math.pow(radius, 2) * Math.PI);
+          })
+          .handle((result, ex) -> {
+              if (ex == null) {
+                  return result;
+              } else {
+                  return -1L;
+              }
+          })
+          .get();
+
+        Assertions.assertThat(actual).isEqualTo(expected);
+    }
+
+    @ParameterizedTest
+    @MethodSource("parametersSource_exceptionally")
+    void whenCompletableFutureIsScheduled_thenExceptionallyExecutedOnlyOnFailure(int a, int b, int c, long expected)
+      throws ExecutionException, InterruptedException {
+        long actual = CompletableFuture
+          .supplyAsync(() -> {
+              if (a <= 0 || b <= 0 || c <= 0) {
+                  throw new IllegalArgumentException(String.format("Supplied with incorrect edge length [%s]", List.of(a, b, c)));
+              }
+              return a * b * c;
+          })
+          .exceptionally((ex) -> -1)
+          .get();
+
+        Assertions.assertThat(actual).isEqualTo(expected);
+    }
+
+    @ParameterizedTest
+    @MethodSource("parametersSource_exceptionally")
+    void givenCompletableFutureIsScheduled_whenHandleIsAlreadyPresent_thenExceptionallyIsNotExecuted(int a, int b, int c, long expected)
+      throws ExecutionException, InterruptedException {
+        long actual = CompletableFuture
+          .supplyAsync(() -> {
+              if (a <= 0 || b <= 0 || c <= 0) {
+                  throw new IllegalArgumentException(String.format("Supplied with incorrect edge length [%s]", List.of(a, b, c)));
+              }
+              return a * b * c;
+          })
+          .handle((result, throwable) -> {
+              if (throwable != null) {
+                  return -1;
+              }
+              return result;
+          })
+          .exceptionally((ex) -> {
+              System.exit(1);
+              return 0;
+          })
+          .get();
+
+        Assertions.assertThat(actual).isEqualTo(expected);
+    }
+
+    @ParameterizedTest
+    @MethodSource("parametersSource_whenComplete")
+    void whenCompletableFutureIsScheduled_thenWhenCompletedExecutedAlways(Double a, long expected, Class<Exception> ifAny) {
+        try {
+            CountDownLatch countDownLatch = new CountDownLatch(1);
+
+            long actual = CompletableFuture
+              .supplyAsync(() -> {
+                  if (a.isNaN()) {
+                      throw new IllegalArgumentException("Supplied value is NaN");
+                  }
+                  return Math.round(Math.pow(a, 2));
+              })
+              .whenComplete((result, exception) -> countDownLatch.countDown())
+              .get();
+
+            Assertions.assertThat(countDownLatch.await(20L, java.util.concurrent.TimeUnit.SECONDS));
+            Assertions.assertThat(actual).isEqualTo(expected);
+        } catch (Exception e) {
+            Assertions.assertThat(e.getClass()).isSameAs(ExecutionException.class);
+            Assertions.assertThat(e.getCause().getClass()).isSameAs(ifAny);
+        }
+    }
+
+    static Stream<Arguments> parametersSource_handle() {
+        return Stream.of(
+          Arguments.of(1, 3),
+          Arguments.of(-1, -1)
+        );
+    }
+
+    static Stream<Arguments> parametersSource_exceptionally() {
+        return Stream.of(
+          Arguments.of(1, 5, 5, 25),
+          Arguments.of(-1, 10, 15, -1)
+        );
+    }
+
+    static Stream<Arguments> parametersSource_whenComplete() {
+        return Stream.of(
+          Arguments.of(2d, 4, null),
+          Arguments.of(Double.NaN, 1, IllegalArgumentException.class)
+        );
+    }
+}

core-java-modules/core-java-concurrency-basic-3/README.md

@@ -11,4 +11,5 @@ This module contains articles about basic Java concurrency.
 - [CompletableFuture and ThreadPool in Java](https://www.baeldung.com/java-completablefuture-threadpool)
 - [CompletableFuture allOf().join() vs. CompletableFuture.join()](https://www.baeldung.com/java-completablefuture-allof-join)
 - [Retry Logic with CompletableFuture](https://www.baeldung.com/java-completablefuture-retry-logic)
+- [Convert From List of CompletableFuture to CompletableFuture List](https://www.baeldung.com/java-completablefuture-list-convert)
 - [[<-- Prev]](../core-java-concurrency-basic-2)

core-java-modules/core-java-concurrency-basic-3/src/main/java/com/baeldung/concurrent/synchronizestatic/atomicinteger/Employee.java

@@ -0,0 +1,30 @@
+package com.baeldung.concurrent.synchronizestatic.atomicinteger;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Synchronizing static variable with AtomicInteger.
+ */
+public class Employee {
+
+    private static final AtomicInteger count = new AtomicInteger(0);
+
+    int id;
+    String name;
+    String title;
+
+    public Employee(int id, String name, String title) {
+        incrementCount();
+        this.id = id;
+        this.name = name;
+        this.title = title;
+    }
+
+    private static void incrementCount() {
+        count.incrementAndGet();
+    }
+
+    public static int getCount() {
+        return count.get();
+    }
+}

core-java-modules/core-java-concurrency-basic-3/src/main/java/com/baeldung/concurrent/synchronizestatic/none/Employee.java

@@ -0,0 +1,27 @@
+package com.baeldung.concurrent.synchronizestatic.none;
+
+/**
+ * No synchronization.
+ */
+public class Employee {
+
+    static int count;
+    int id;
+    String name;
+    String title;
+
+    public Employee(int id, String name, String title) {
+        incrementCount();
+        this.id = id;
+        this.name = name;
+        this.title = title;
+    }
+
+    private static void incrementCount() {
+        System.out.println("Count = " + ++count);
+    }
+
+    public static Integer getCount() {
+        return count;
+    }
+}

core-java-modules/core-java-concurrency-basic-3/src/main/java/com/baeldung/concurrent/synchronizestatic/reentrantlock/Employee.java

@@ -0,0 +1,43 @@
+package com.baeldung.concurrent.synchronizestatic.reentrantlock;
+
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * Synchronizing static variable with a Reenatrant Lock.
+ */
+public class Employee {
+
+    private static final ReentrantLock lock = new ReentrantLock();
+
+    static int count;
+    int id;
+    String name;
+    String title;
+
+    public Employee(int id, String name, String title) {
+        incrementCount();
+        this.id = id;
+        this.name = name;
+        this.title = title;
+    }
+
+    private static void incrementCount() {
+        lock.lock();
+        try {
+            System.out.println("Count = " + ++count);
+        }
+        finally {
+            lock.unlock();
+        }
+    }
+
+    public static int getCount() {
+        lock.lock();
+        try {
+            return count;
+        }
+        finally {
+            lock.unlock();
+        }
+    }
+}

core-java-modules/core-java-concurrency-basic-3/src/main/java/com/baeldung/concurrent/synchronizestatic/synchronizedblock/Employee.java

@@ -0,0 +1,33 @@
+package com.baeldung.concurrent.synchronizestatic.synchronizedblock;
+
+/**
+ * Synchronizing static variable with a synchronized block.
+ */
+public class Employee {
+
+    private static final Object lock = new Object();
+
+    static int count;
+    int id;
+    String name;
+    String title;
+
+    public Employee(int id, String name, String title) {
+        incrementCount();
+        this.id = id;
+        this.name = name;
+        this.title = title;
+    }
+
+    private static void incrementCount() {
+        synchronized(lock) {
+            System.out.println("Count = " + ++count);
+        }
+    }
+
+    public static int getCount() {
+        synchronized(lock) {
+            return count;
+        }
+    }
+}

core-java-modules/core-java-concurrency-basic-3/src/main/java/com/baeldung/concurrent/synchronizestatic/synchronizedclass/Employee.java

@@ -0,0 +1,31 @@
+package com.baeldung.concurrent.synchronizestatic.synchronizedclass;
+
+/**
+ * Synchronizing static variable with a synchronized block.
+ */
+public class Employee
+{
+    static int count;
+    int id;
+    String name;
+    String title;
+
+    public Employee(int id, String name, String title) {
+        incrementCount();
+        this.id = id;
+        this.name = name;
+        this.title = title;
+    }
+
+    private static void incrementCount() {
+        synchronized(Employee.class) {
+            System.out.println("Count = " + ++count);
+        }
+    }
+
+    public static int getCount() {
+        synchronized(Employee.class) {
+            return count;
+        }
+    }
+}

core-java-modules/core-java-concurrency-basic-3/src/main/java/com/baeldung/concurrent/synchronizestatic/synchronizedmethod/Employee.java

@@ -0,0 +1,27 @@
+package com.baeldung.concurrent.synchronizestatic.synchronizedmethod;
+
+/**
+ * Synchronizing static variable with a synchronized method.
+ */
+public class Employee {
+    static int count;
+    int id;
+    String name;
+    String title;
+
+    public Employee(int id, String name, String title)
+    {
+        incrementCount();
+        this.id = id;
+        this.name = name;
+        this.title = title;
+    }
+
+    private static synchronized void incrementCount() {
+        System.out.println("Count = " + ++count);
+    }
+
+    public static synchronized int getCount() {
+        return count;
+    }
+}

core-java-modules/core-java-concurrency-basic-3/src/test/java/com/baeldung/concurrent/synchronizestatic/SychronizeStaticDataUnitTest.java

@@ -0,0 +1,90 @@
+package com.baeldung.concurrent.synchronizestatic;
+
+import org.junit.Test;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+
+/**
+ * The tests in this class show the output of creating multiple
+ * types of Employee classes in the <code>synchronizedstatic</code>
+ * package. When not synchronized the out will not be sequential;
+ * when it is synchronized the output will be in sequential.
+ */
+public class SychronizeStaticDataUnitTest {
+    private final Executor pool = Executors.newFixedThreadPool(4);
+
+    private final int numberToTest = 100;
+
+    @Test
+    public void whenNotSynchronized_thenDataOutOfOrder() {
+
+        System.out.println("No synchronization");
+
+        for(int i = 0; i < numberToTest; i++) {
+            int finalI = i;
+            pool.execute(() -> {
+                new com.baeldung.concurrent.synchronizestatic.none.Employee(finalI, "John", "Smith");
+            });
+        }
+    }
+
+    @Test
+    public void whenSynchronizedMethod_thenDataInOrder() {
+
+        System.out.println("Synchronization with synchronized method");
+
+        for(int i = 0; i < numberToTest; i++) {
+            int finalI = i;
+            pool.execute(() -> {
+                new com.baeldung.concurrent.synchronizestatic.synchronizedmethod.Employee(finalI, "John", "Smith");
+            });
+        }
+    }
+
+    @Test
+    public void whenSynchronizedClass_thenDataInOrder() {
+
+        System.out.println("Synchronization with synchronized block on class");
+
+        for(int i = 0; i < numberToTest; i++) {
+            int finalI = i;
+            pool.execute(() -> {
+                new com.baeldung.concurrent.synchronizestatic.synchronizedclass.Employee(finalI, "John", "Smith");
+            });
+        }
+    }
+
+    @Test
+    public void whenSynchronizedBlock_thenDataInOrder() {
+
+        System.out.println("Synchronization with synchronized block on a private object");
+
+        for(int i = 0; i < numberToTest; i++) {
+            int finalI = i;
+            pool.execute(() -> {
+               new com.baeldung.concurrent.synchronizestatic.synchronizedblock.Employee(finalI, "John", "Smith");
+            });
+        }
+    }
+
+    @Test
+    public void whenAtomicInteger_thenDataInOrder() {
+        // Not straight forward to test this because we cannot log/print
+        // and increment values in a synchronized fashion like other
+        // tests
+    }
+
+    @Test
+    public void whenReentrantLock_thenDataInOrder() {
+
+        System.out.println("Synchronization with ReentrantLock");
+
+        for(int i = 0; i < numberToTest; i++) {
+            int finalI = i;
+            pool.execute(() -> {
+                new com.baeldung.concurrent.synchronizestatic.reentrantlock.Employee(finalI, "John", "Smith");
+            });
+        }
+    }
+}

core-java-modules/core-java-conditionals/pom.xml

@@ -5,7 +5,7 @@
     <modelVersion>4.0.0</modelVersion>
     <artifactId>core-java-conditionals</artifactId>
     <version>0.1.0-SNAPSHOT</version>
-    <name>core-java-compiler</name>
+    <name>core-java-conditionals</name>
     <packaging>jar</packaging>
 
     <parent>

core-java-modules/core-java-console/pom.xml

@@ -29,6 +29,11 @@
                 </exclusion>
             </exclusions>
         </dependency>
+        <dependency>
+            <groupId>de.vandermeer</groupId>
+            <artifactId>asciitable</artifactId>
+            <version>${ascii.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -157,6 +162,7 @@
         <maven-javadoc-plugin.version>3.0.0-M1</maven-javadoc-plugin.version>
         <source.version>1.8</source.version>
         <target.version>1.8</target.version>
+        <ascii.version>0.3.2</ascii.version>
     </properties>
 
 </project>

core-java-modules/core-java-console/src/main/java/com/baeldung/consoletableoutput/BodyMassIndex.java

@@ -0,0 +1,44 @@
+package com.baeldung.consoletableoutput;
+
+public class BodyMassIndex {
+
+    private String name;
+    private double height;
+    private double weight;
+
+    public BodyMassIndex(String name, double height, double weight) {
+        this.name = name;
+        this.height = height;
+        this.weight = weight;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public double getHeight() {
+        return height;
+    }
+
+    public void setHeight(double height) {
+        this.height = height;
+    }
+
+    public double getWeight() {
+        return weight;
+    }
+
+    public void setWeight(double weight) {
+        this.weight = weight;
+    }
+
+    public double calculate() {
+        double bmi = weight / (height * height);
+        String formattedBmi = String.format("%.2f", bmi);
+        return Double.parseDouble(formattedBmi);
+    }
+}

core-java-modules/core-java-console/src/main/java/com/baeldung/consoletableoutput/BodyMassIndexApplication.java

@@ -0,0 +1,62 @@
+package com.baeldung.consoletableoutput;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import de.vandermeer.asciitable.AsciiTable;
+import de.vandermeer.skb.interfaces.transformers.textformat.TextAlignment;
+
+public class BodyMassIndexApplication {
+
+    public static void main(String[] args) {
+        stringFormat();
+        asciiTable();
+
+    }
+
+    public static void stringFormat() {
+        List<BodyMassIndex> bodyMassIndices = new ArrayList<>();
+        bodyMassIndices.add(new BodyMassIndex("Tom", 1.8, 80));
+        bodyMassIndices.add(new BodyMassIndex("Elton", 1.9, 90));
+        bodyMassIndices.add(new BodyMassIndex("Harry", 1.9, 90));
+        bodyMassIndices.add(new BodyMassIndex("Hannah", 1.9, 90));
+
+        String leftAlignment = "| %-7s | %-7.2f | %-7.2f | %-5.2f |%n";
+
+        System.out.format("+---------+---------+---------+-------+%n");
+        System.out.format("| Name    | Height  |  Weight | BMI   |%n");
+        System.out.format("+---------+---------+---------+-------+%n");
+
+        for (BodyMassIndex bodyMassIndex : bodyMassIndices) {
+            System.out.format(leftAlignment, bodyMassIndex.getName(), bodyMassIndex.getHeight(), bodyMassIndex.getWeight(), bodyMassIndex.calculate());
+            System.out.format("+---------+---------+---------+-------+%n");
+        }
+
+    }
+
+    public static void asciiTable() {
+        List<BodyMassIndex> bodyMassIndices = new ArrayList<>();
+        bodyMassIndices.add(new BodyMassIndex("Tom", 1.8, 80));
+        bodyMassIndices.add(new BodyMassIndex("Elton", 1.9, 90));
+        bodyMassIndices.add(new BodyMassIndex("Harry", 1.9, 90));
+        bodyMassIndices.add(new BodyMassIndex("Hannah", 1.9, 90));
+
+        AsciiTable asciiTable = new AsciiTable();
+        asciiTable.addRule();
+        asciiTable.addRow("Name", "Height", "Weight", "BMI");
+        asciiTable.addRule();
+
+        for (BodyMassIndex bodyMassIndex : bodyMassIndices) {
+
+            asciiTable.addRow(bodyMassIndex.getName(), bodyMassIndex.getHeight(), bodyMassIndex.getWeight(), bodyMassIndex.calculate());
+            asciiTable.addRule();
+
+        }
+
+        asciiTable.setTextAlignment(TextAlignment.CENTER);
+        String render = asciiTable.render();
+        System.out.println(render);
+
+    }
+
+}

core-java-modules/core-java-date-operations-1/pom.xml

@@ -54,7 +54,7 @@
     </build>
 
     <properties>
-        <joda-time.version>2.10</joda-time.version>
+        <joda-time.version>2.12.5</joda-time.version>
         <hirondelle-date4j.version>RELEASE</hirondelle-date4j.version>
         <maven.compiler.source>1.9</maven.compiler.source>
         <maven.compiler.target>1.9</maven.compiler.target>

core-java-modules/core-java-date-operations-2/pom.xml

@@ -47,7 +47,7 @@
     </dependencies>
 
     <properties>
-        <joda-time.version>2.10</joda-time.version>
+        <joda-time.version>2.12.5</joda-time.version>
         <hirondelle-date4j.version>1.5.1</hirondelle-date4j.version>
         <prettytime.version>3.2.7.Final</prettytime.version>
         <time4j-base.version>5.9</time4j-base.version>

core-java-modules/core-java-date-operations-3/README.md

@@ -11,4 +11,6 @@ This module contains articles about date operations in Java.
 - [Getting Yesterday’s Date in Java](https://www.baeldung.com/java-find-yesterdays-date)
 - [How to Get the Start and End Dates of a Year Using Java](https://www.baeldung.com/java-date-year-start-end)
 - [Convert Between Java LocalDate and Epoch](https://www.baeldung.com/java-localdate-epoch)
+- [Get First Date of Current Month in Java](https://www.baeldung.com/java-current-month-start-date)
+- [Time Conversions Using TimeUnit](https://www.baeldung.com/java-timeunit-conversion)
 - [[<-- Prev]](/core-java-modules/core-java-date-operations-2)

core-java-modules/core-java-date-operations-3/pom.xml

@@ -28,7 +28,6 @@
 
     <properties>
         <joda-time.version>2.12.5</joda-time.version>
-        <commons-lang3.version>3.12.0</commons-lang3.version>
     </properties>
 
 </project>

core-java-modules/core-java-date-operations-3/src/test/java/com/baeldung/timeunitconversions/TimeUnitConversionsUnitTest.java

@@ -0,0 +1,105 @@
+package com.baeldung.timeunitconversions;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.concurrent.TimeUnit;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class TimeUnitConversionsUnitTest {
+
+
+    @Test
+    void givenSeconds_whenConvertToMinutes_thenCorrect() {
+        int input = 60;
+
+        long minutes = TimeUnit.MINUTES.convert(input, TimeUnit.SECONDS);
+
+        assertThat(minutes).isEqualTo(1);
+    }
+
+    @Test
+    void givenMinutes_whenConvertToSeconds_thenCorrect() {
+        int input = 1;
+
+        long seconds = TimeUnit.SECONDS.convert(input, TimeUnit.MINUTES);
+
+        assertThat(seconds).isEqualTo(60);
+    }
+
+    @Test
+    void givenSeconds_whenToMinutes_thenCorrect() {
+        int input = 60;
+
+        long minutes = TimeUnit.SECONDS.toMinutes(input);
+
+        assertThat(minutes).isEqualTo(1);
+    }
+
+    @Test
+    void givenMinutes_whenToSeconds_thenCorrect() {
+        int input = 1;
+
+        long seconds = TimeUnit.MINUTES.toSeconds(input);
+
+        assertThat(seconds).isEqualTo(60);
+    }
+
+    @Test
+    void givenNegativeInput_whenToMinutes_thenCorrect() {
+        int input = -60;
+
+        long minutes = TimeUnit.SECONDS.toMinutes(input);
+        assertThat(minutes).isEqualTo(-1);
+    }
+
+    @Test
+    void givenNonTotalInput_whenToMinutes_thenCorrectTotalResultWithDecimalTruncate() {
+        long positiveUnder = TimeUnit.SECONDS.toMinutes(59);
+        long positiveAbove = TimeUnit.SECONDS.toMinutes(61);
+
+        assertThat(positiveUnder).isEqualTo(0);
+        assertThat(positiveAbove).isEqualTo(1);
+    }
+
+    @Test
+    void givenNonTotalNegativeInput_whenToMinutes_thenCorrectTotalResultWithDecimalTruncate() {
+        long negativeUnder = TimeUnit.SECONDS.toMinutes(-59);
+        long negativeAbove = TimeUnit.SECONDS.toMinutes(-61);
+
+        assertThat(negativeUnder).isEqualTo(0);
+        assertThat(negativeAbove).isEqualTo(-1);
+    }
+
+    @Test
+    void givenOverflowInput_whenToMillis_thenTruncatedToLimit() {
+        long maxMillis = TimeUnit.DAYS.toMillis(Long.MAX_VALUE);
+        long minMillis = TimeUnit.DAYS.toMillis(Long.MIN_VALUE);
+
+        assertThat(maxMillis).isEqualTo(Long.MAX_VALUE);
+        assertThat(minMillis).isEqualTo(Long.MIN_VALUE);
+    }
+
+    @Test
+    void givenInput_whenExtractFineTimeUnits_thenCorrect() {
+        long inputSeconds = 3672;
+
+        long hours = TimeUnit.SECONDS.toHours(inputSeconds);
+
+        long secondsRemainingAfterHours = inputSeconds - TimeUnit.HOURS.toSeconds(hours);
+        long minutes = TimeUnit.SECONDS.toMinutes(secondsRemainingAfterHours);
+
+        long seconds = secondsRemainingAfterHours - TimeUnit.MINUTES.toSeconds(minutes);
+
+
+        assertThat(hours).isEqualTo(1);
+        assertThat(minutes).isEqualTo(1);
+        assertThat(seconds).isEqualTo(12);
+
+        assertThat(inputSeconds).isEqualTo(
+            (hours * 60 * 60) +
+            (minutes * 60) +
+            (seconds)
+        );
+    }
+}

core-java-modules/core-java-datetime-conversion/pom.xml

@@ -54,7 +54,7 @@
     </build>
 
     <properties>
-        <joda-time.version>2.10</joda-time.version>
+        <joda-time.version>2.12.5</joda-time.version>
         <maven.compiler.source>1.9</maven.compiler.source>
         <maven.compiler.target>1.9</maven.compiler.target>
     </properties>

core-java-modules/core-java-datetime-conversion/src/main/java/com/baeldung/timestamptolong/TimestampToLong.java

@@ -0,0 +1,31 @@
+package com.baeldung.timestamptolong;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.Date;
+
+public class TimestampToLong {
+
+    public long usingSimpleDateFormat(String timestampString) throws ParseException {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+        Date date = sdf.parse(timestampString);
+        String currentDateString = sdf.format(date);
+        return sdf.parse(currentDateString).getTime();
+    }
+
+    public long usingInstantClass(String timestampString) {
+        Instant instant = LocalDateTime.parse(timestampString, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"))
+                .atZone(ZoneId.systemDefault())
+                .toInstant();
+        return instant.toEpochMilli();
+    }
+
+    public long usingJava8DateTime(String timestampString) {
+        LocalDateTime localDateTime = LocalDateTime.parse(timestampString.replace(" ", "T"));
+        return localDateTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
+    }
+}

core-java-modules/core-java-datetime-conversion/src/test/java/com/baeldung/timestamptolong/TimestampToLongUnitTest.java

@@ -0,0 +1,43 @@
+package com.baeldung.timestamptolong;
+
+import org.junit.Test;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.Date;
+
+import static org.junit.Assert.assertEquals;
+
+public class TimestampToLongUnitTest {
+    private static final String timestampString = "2023-11-15 01:02:03";
+
+    @Test
+    public void givenSimpleDateFormat_whenFormattingDate_thenConvertToLong() throws ParseException {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+        Date date = sdf.parse(timestampString);
+
+        String currentDateString = sdf.format(date);
+        long actualTimestamp = sdf.parse(currentDateString).getTime();
+        assertEquals(1700010123000L, actualTimestamp);
+    }
+
+    @Test
+    public void givenInstantClass_whenGettingTimestamp_thenConvertToLong() {
+        Instant instant = LocalDateTime.parse(timestampString, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"))
+                .atZone(ZoneId.systemDefault())
+                .toInstant();
+        long actualTimestamp = instant.toEpochMilli();
+        assertEquals(1700010123000L, actualTimestamp);
+    }
+
+    @Test
+    public void givenJava8DateTime_whenGettingTimestamp_thenConvertToLong() {
+        LocalDateTime localDateTime = LocalDateTime.parse(timestampString.replace(" ", "T"));
+        long actualTimestamp = localDateTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
+        assertEquals(1700010123000L, actualTimestamp);
+    }
+}

core-java-modules/core-java-datetime-string/pom.xml

@@ -64,7 +64,7 @@
     </build>
 
     <properties>
-        <commons-validator.version>1.6</commons-validator.version>
+        <commons-validator.version>1.7</commons-validator.version>
         <joda-time.version>2.12.5</joda-time.version>
         <hirondelle-date4j.version>RELEASE</hirondelle-date4j.version>
         <maven.compiler.source>1.9</maven.compiler.source>

core-java-modules/core-java-datetime-string/src/test/java/com/baeldung/formatinstant/FormatInstantUnitTest.java

@@ -6,6 +6,7 @@ import java.time.Instant;
 import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.time.temporal.UnsupportedTemporalTypeException;
+import java.util.TimeZone;
 
 import org.joda.time.format.DateTimeFormat;
 import org.junit.Test;
@@ -17,7 +18,7 @@ public class FormatInstantUnitTest {
     @Test
     public void givenInstant_whenUsingDateTimeFormatter_thenFormat() {
         DateTimeFormatter formatter = DateTimeFormatter.ofPattern(PATTERN_FORMAT)
-            .withZone(ZoneId.systemDefault());
+            .withZone(TimeZone.getTimeZone("UTC").toZoneId());
 
         Instant instant = Instant.parse("2022-02-15T18:35:24.00Z");
         String formattedInstant = formatter.format(instant);

core-java-modules/core-java-documentation/README.md

@@ -4,3 +4,4 @@
 
 - [Introduction to Javadoc](http://www.baeldung.com/javadoc)
 - [Code Snippets in Java API Documentation](https://www.baeldung.com/java-doc-code-snippets)
+- [How to Document Generic Type Parameters in Javadoc](https://www.baeldung.com/java-javadoc-generic-type-parameters)

core-java-modules/core-java-function/pom.xml

@@ -51,7 +51,6 @@
     <properties>
         <mockito-inline.version>3.8.0</mockito-inline.version>
         <assertj.version>3.22.0</assertj.version>
-        <commons-lang3.version>3.12.0</commons-lang3.version>
         <vavr.version>0.10.4</vavr.version>
     </properties>
 

core-java-modules/core-java-functional/pom.xml

@@ -35,7 +35,6 @@
     <properties>
         <mockito-inline.version>3.8.0</mockito-inline.version>
         <assertj.version>3.22.0</assertj.version>
-        <commons-lang3.version>3.12.0</commons-lang3.version>
         <vavr.version>0.10.4</vavr.version>
     </properties>
 

core-java-modules/core-java-hex/test/java/com/baeldung/hextoint/HexToIntConversionUnitTest.java

@@ -0,0 +1,42 @@
+package com.baeldung.hextoint;
+
+import org.junit.Test;
+
+import java.math.BigInteger;
+
+import static org.junit.Assert.assertEquals;
+
+public class HexToIntConversionUnitTest {
+
+    @Test
+    public void givenValidHexString_whenUsingParseInt_thenExpectCorrectDecimalValue() {
+        String hexString = "0x00FF00";
+        int expectedDecimalValue = 65280;
+
+        int decimalValue = Integer.parseInt(hexString.substring(2), 16);
+
+        assertEquals(expectedDecimalValue, decimalValue);
+    }
+
+    @Test
+    public void givenValidHexString_whenUsingIntegerDecode_thenExpectCorrectDecimalValue() {
+        String hexString = "0x00FF00";
+        int expectedDecimalValue = 65280;
+
+        int decimalValue = Integer.decode(hexString);
+
+        assertEquals(expectedDecimalValue, decimalValue);
+    }
+
+    @Test
+    public void givenValidHexString_whenUsingBigInteger_thenExpectCorrectDecimalValue() {
+        String hexString = "0x00FF00";
+        int expectedDecimalValue = 65280;
+
+        BigInteger bigIntegerValue = new BigInteger(hexString.substring(2), 16);
+        int decimalValue = bigIntegerValue.intValue();
+        assertEquals(expectedDecimalValue, decimalValue);
+    }
+
+
+}

core-java-modules/core-java-io-5/README.md

@@ -5,5 +5,6 @@ This module contains articles about core Java input and output (IO)
 ### Relevant Articles: 
 - [Get File Extension From MIME Type in Java](https://www.baeldung.com/java-mime-type-file-extension)
 - [How to Remove Line Breaks From a File in Java](https://www.baeldung.com/java-file-remove-line-breaks)
+- [Difference Between ZipFile and ZipInputStream in Java](https://www.baeldung.com/java-zipfile-vs-zipinputstream)
 - [[<-- Prev]](/core-java-modules/core-java-io-4)
 

core-java-modules/core-java-io-apis-2/README.md

@@ -8,3 +8,4 @@ This module contains articles about core Java input/output(IO) APIs.
 - [Check if a File Is Empty in Java](https://www.baeldung.com/java-check-file-empty)
 - [Converting Relative to Absolute Paths in Java](https://www.baeldung.com/java-from-relative-to-absolute-paths)
 - [Detect EOF in Java](https://www.baeldung.com/java-file-detect-end-of-file)
+- [PrintWriter vs. FileWriter in Java](https://www.baeldung.com/java-printwriter-filewriter-difference)

core-java-modules/core-java-io-conversions-2/src/test/java/com/baeldung/filetofrombytearray/FileToByteArrayUnitTest.java

@@ -0,0 +1,63 @@
+package com.baeldung.filetofrombytearray;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.IOUtils;
+import org.junit.jupiter.api.Test;
+
+class FileToByteArrayUnitTest {
+
+    private static final String FILE_NAME = "src" + File.separator + "test" + File.separator + "resources" + File.separator + "sample.txt";
+    private final byte[] expectedByteArray = { 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100 };
+
+    @Test
+    void givenFile_whenUsingFileInputStreamClass_thenConvert() throws IOException {
+        File myFile = new File(FILE_NAME);
+        byte[] byteArray = new byte[(int) myFile.length()];
+        try (FileInputStream inputStream = new FileInputStream(myFile)) {
+            inputStream.read(byteArray);
+        }
+
+        assertArrayEquals(expectedByteArray, byteArray);
+    }
+
+    @Test
+    void givenFile_whenUsingNioApiFilesClass_thenConvert() throws IOException {
+        byte[] byteArray = Files.readAllBytes(Paths.get(FILE_NAME));
+
+        assertArrayEquals(expectedByteArray, byteArray);
+    }
+
+    @Test
+    void givenFile_whenUsingApacheCommonsIOUtilsClass_thenConvert() throws IOException {
+        File myFile = new File(FILE_NAME);
+        byte[] byteArray = new byte[(int) myFile.length()];
+        try (FileInputStream inputStream = new FileInputStream(myFile)) {
+            byteArray = IOUtils.toByteArray(inputStream);
+        }
+
+        assertArrayEquals(expectedByteArray, byteArray);
+    }
+
+    @Test
+    void givenFile_whenUsingApacheCommonsFileUtilsClass_thenConvert() throws IOException {
+        byte[] byteArray = FileUtils.readFileToByteArray(new File(FILE_NAME));
+
+        assertArrayEquals(expectedByteArray, byteArray);
+    }
+
+    @Test
+    void givenFile_whenUsingGuavaFilesClass_thenConvert() throws IOException {
+        byte[] byteArray = com.google.common.io.Files.toByteArray(new File(FILE_NAME));
+
+        assertArrayEquals(expectedByteArray, byteArray);
+    }
+
+}

core-java-modules/core-java-io/src/main/java/com/baeldung/size/FileSizeUtils.java

@@ -0,0 +1,28 @@
+package com.baeldung.size;
+
+import java.io.File;
+
+public class FileSizeUtils {
+    public static long getFileSizeInBytes(File file) {
+        if (file.exists()) {
+            return file.length();
+        } else {
+            throw new IllegalArgumentException("File not found.");
+        }
+    }
+
+    public static double getFileSizeInKilobytes(File file) {
+        long bytes = getFileSizeInBytes(file);
+        return (double) bytes / 1024;
+    }
+
+    public static double getFileSizeInMegabytes(File file) {
+        double kilobytes = getFileSizeInKilobytes(file);
+        return kilobytes / 1024;
+    }
+
+    public static double getFileSizeInGigabytes(File file) {
+        double megabytes = getFileSizeInMegabytes(file);
+        return megabytes / 1024;
+    }
+}

core-java-modules/core-java-io/src/test/java/com/baeldung/size/JavaFileSizeUnitTest.java

@@ -1,6 +1,8 @@
 package com.baeldung.size;
 
-import static org.junit.Assert.assertEquals;
+import org.apache.commons.io.FileUtils;
+import org.junit.Before;
+import org.junit.Test;
 
 import java.io.File;
 import java.io.FileInputStream;
@@ -10,9 +12,9 @@ import java.net.URL;
 import java.nio.channels.FileChannel;
 import java.nio.file.Path;
 import java.nio.file.Paths;
-import org.apache.commons.io.FileUtils;
-import org.junit.Before;
-import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
 
 public class JavaFileSizeUnitTest {
     private static final long EXPECTED_FILE_SIZE_IN_BYTES = 11;
@@ -85,4 +87,23 @@ public class JavaFileSizeUnitTest {
             assertEquals(EXPECTED_FILE_SIZE_IN_BYTES, stream.available());
         }
     }
-}
+
+    @Test
+    public void whenGetFileSizeInDifferentUnits_thenCorrect(){
+        filePath = String.join(File.separator, new String[] { "src", "test", "resources", "size", "sample_file_1.in" });
+        File file = new File(filePath);
+        if (file.exists()) {
+            long expectedBytes = file.length();
+            double expectedKilobytes = (double) expectedBytes / 1024;
+            double expectedMegabytes = expectedKilobytes / 1024;
+            double expectedGigabytes = expectedMegabytes / 1024;
+
+            assertEquals(expectedBytes, FileSizeUtils.getFileSizeInBytes(file));
+            assertEquals(expectedKilobytes, FileSizeUtils.getFileSizeInKilobytes(file), 0.01);
+            assertEquals(expectedMegabytes, FileSizeUtils.getFileSizeInMegabytes(file), 0.01);
+            assertEquals(expectedGigabytes, FileSizeUtils.getFileSizeInGigabytes(file), 0.01);
+        } else {
+            fail("File not found.");
+        }
+    }
+}

core-java-modules/core-java-jndi/README.md

@@ -4,3 +4,4 @@
 - [Java Naming and Directory Interface Overview](https://www.baeldung.com/jndi)
 - [LDAP Authentication Using Pure Java](https://www.baeldung.com/java-ldap-auth)
 - [Testing LDAP Connections With Java](https://www.baeldung.com/java-test-ldap-connections)
+- [JNDI – What Is java:comp/env?](https://www.baeldung.com/java-jndi-comp-env)

core-java-modules/core-java-lang-5/pom.xml

@@ -24,7 +24,6 @@
     </build>
 
     <properties>
-        <commons-lang3.version>3.12.0</commons-lang3.version>
         <reflections.version>0.10.2</reflections.version>
     </properties>
 

core-java-modules/core-java-lang-6/pom.xml

@@ -29,7 +29,6 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.5.1</version>
                 <configuration>
                     <source>17</source>
                     <target>17</target>
@@ -50,7 +49,7 @@
         <maven.compiler.source>17</maven.compiler.source>
         <maven.compiler.target>17</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <mapstruct.version>1.5.5.Final</mapstruct.version>
+        <mapstruct.version>1.6.0.Beta1</mapstruct.version>
     </properties>
 
 </project>

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/compressbytes/CompressByteArrayUtil.java

@@ -0,0 +1,58 @@
+package com.baeldung.compressbytes;
+
+import java.io.ByteArrayOutputStream;
+import java.util.zip.DataFormatException;
+import java.util.zip.Deflater;
+import java.util.zip.Inflater;
+
+public class CompressByteArrayUtil {
+
+    public static byte[] compress(byte[] input) {
+        Deflater deflater = new Deflater();
+        deflater.setInput(input);
+        deflater.finish();
+
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        byte[] buffer = new byte[1024];
+
+        while (!deflater.finished()) {
+            int compressedSize = deflater.deflate(buffer);
+            outputStream.write(buffer, 0, compressedSize);
+        }
+
+        return outputStream.toByteArray();
+    }
+
+    public static byte[] decompress(byte[] input) throws DataFormatException {
+        Inflater inflater = new Inflater();
+        inflater.setInput(input);
+
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        byte[] buffer = new byte[1024];
+
+        while (!inflater.finished()) {
+            int decompressedSize = inflater.inflate(buffer);
+            outputStream.write(buffer, 0, decompressedSize);
+        }
+
+        return outputStream.toByteArray();
+    }
+
+    public static void main(String[] args) throws Exception {
+        String inputString = "Baeldung helps developers explore the Java ecosystem and simply be better engineers. " +
+                "We publish to-the-point guides and courses, with a strong focus on building web applications, Spring, " +
+                "Spring Security, and RESTful APIs";
+        byte[] input = inputString.getBytes();
+
+        // Compression
+        byte[] compressedData = compress(input);
+
+        // Decompression
+        byte[] decompressedData = decompress(compressedData);
+
+        System.out.println("Original: " + input.length + " bytes");
+        System.out.println("Compressed: " + compressedData.length + " bytes");
+        System.out.println("Decompressed: " + decompressedData.length + " bytes");
+    }
+
+}

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/stopexecution/InterruptThread.java

@@ -4,9 +4,7 @@ public class InterruptThread extends Thread {
     @Override
     public void run() {
         while (!isInterrupted()) {
-            if (isInterrupted()) {
-                break;
-            }
+            break;
             // business logic
         }
     }

core-java-modules/core-java-networking-2/pom.xml

@@ -56,7 +56,7 @@
         <async-http-client.version>2.4.5</async-http-client.version>
         <jakarta.bind.version>2.3.3</jakarta.bind.version>
         <greenmail.version>2.0.0-alpha-3</greenmail.version>
-        <commons-codec.version>1.15</commons-codec.version>
+        <commons-codec.version>1.16.0</commons-codec.version>
     </properties>
 
 </project>

core-java-modules/core-java-numbers-6/pom.xml

@@ -42,7 +42,6 @@
     </build>
 
     <properties>
-        <commons-codec>1.15</commons-codec>
-        <guava.version>32.1.2-jre</guava.version>
+        <commons-codec>1.16.0</commons-codec>
     </properties>
 </project>

core-java-modules/core-java-numbers-6/src/test/java/com/baeldung/genericnumberscomparator/GenericNumbersComparatorUnitTest.java

@@ -1,13 +1,12 @@
 package com.baeldung.genericnumberscomparator;
 
+import static org.assertj.core.api.Assertions.entry;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 import java.util.Comparator;
-import java.util.HashMap;
 import java.util.Map;
-import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.function.BiPredicate;
 import java.util.function.Function;
@@ -25,6 +24,7 @@ class GenericNumbersComparatorUnitTest {
         assertEquals(0, compareDouble(5, 5.0));
     }
 
+    // we create a method that compares Integer, but this could also be done for other types e.g. Double, BigInteger
     public int compareTo(Integer int1, Integer int2) {
         return int1.compareTo(int2);
     }
@@ -34,11 +34,10 @@ class GenericNumbersComparatorUnitTest {
         assertEquals(-1, compareTo(5, 7));
     }
 
-    Map<Class<? extends Number>, BiFunction<Number, Number, Integer>> comparisonMap = new HashMap<>();
+    // for this example, we create a function that compares Integer, but this could also be done for other types e.g. Double, BigInteger
+    Map<Class<? extends Number>, BiFunction<Number, Number, Integer>> comparisonMap = Map.ofEntries(entry(Integer.class, (num1, num2) -> ((Integer) num1).compareTo((Integer) num2)));
 
     public int compareUsingMap(Number num1, Number num2) {
-        comparisonMap.put(Integer.class, (a, b) -> ((Integer) num1).compareTo((Integer) num2));
-
         return comparisonMap.get(num1.getClass())
             .apply(num1, num2);
     }
@@ -70,24 +69,6 @@ class GenericNumbersComparatorUnitTest {
         assertEquals(-1, compareUsingReflection(5, 7));
     }
 
-    interface NumberComparatorFactory {
-        Comparator<Number> getComparator();
-    }
-
-    class IntegerComparatorFactory implements NumberComparatorFactory {
-        @Override
-        public Comparator<Number> getComparator() {
-            return (num1, num2) -> ((Integer) num1).compareTo((Integer) num2);
-        }
-    }
-
-    @Test
-    void givenNumbers_whenUseComparatorFactory_thenWillExecuteComparison() {
-        NumberComparatorFactory factory = new IntegerComparatorFactory();
-        Comparator<Number> comparator = factory.getComparator();
-        assertEquals(-1, comparator.compare(5, 7));
-    }
-
     Function<Number, Double> toDouble = Number::doubleValue;
     BiPredicate<Number, Number> isEqual = (num1, num2) -> toDouble.apply(num1)
         .equals(toDouble.apply(num2));
@@ -97,20 +78,7 @@ class GenericNumbersComparatorUnitTest {
         assertEquals(true, isEqual.test(5, 5.0));
     }
 
-    private Number someNumber = 5;
-    private Number anotherNumber = 5.0;
-
-    Optional<Number> optNum1 = Optional.ofNullable(someNumber);
-    Optional<Number> optNum2 = Optional.ofNullable(anotherNumber);
-    int comparisonResult = optNum1.flatMap(n1 -> optNum2.map(n2 -> Double.compare(n1.doubleValue(), n2.doubleValue())))
-        .orElse(0);
-
-    @Test
-    void givenNumbers_whenUseComparisonResult_thenWillExecuteComparison() {
-        assertEquals(0, comparisonResult);
-    }
-
-    private boolean someCondition = true;
+    private boolean someCondition;
     Function<Number, ?> dynamicFunction = someCondition ? Number::doubleValue : Number::intValue;
     Comparator<Number> dynamicComparator = (num1, num2) -> ((Comparable) dynamicFunction.apply(num1)).compareTo(dynamicFunction.apply(num2));
 

core-java-modules/core-java-numbers-conversions/src/test/java/com/baeldung/floatdoubleconversions/FloatDoubleConversionsUnitTest.java

@@ -3,7 +3,7 @@ package com.baeldung.floatdoubleconversions;
 import org.junit.Assert;
 import org.junit.Test;
 
-public class FloatDoubleConversionsTest {
+public class FloatDoubleConversionsUnitTest {
 
     @Test
     public void whenDoubleType_thenFloatTypeSuccess(){

core-java-modules/core-java-optional/pom.xml

@@ -47,14 +47,14 @@
         <dependency>
             <groupId>io.rest-assured</groupId>
             <artifactId>json-path</artifactId>
-            <version>${rest-assured.version}</version>
+            <version>${json-path.version}</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
 
     <properties>
         <hibernate.core.version>5.4.0.Final</hibernate.core.version>
-        <rest-assured.version>3.1.1</rest-assured.version>
+        <json-path.version>5.3.2</json-path.version>
     </properties>
 
 </project>

core-java-modules/core-java-optional/src/test/java/com/baeldung/java9additions/Java9OptionalUnitTest.java

@@ -8,88 +8,88 @@ import java.util.Optional;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.stream.Collectors;
 
-//    Uncomment code when code base is compatible with Java 9
-//public class Java9OptionalUnitTest {
-//
-//    @Test
-//    public void givenOptionalOfSome_whenToStream_thenShouldTreatItAsOneElementStream() {
-//        //given
-//        Optional<String> value = Optional.of("a");
-//
-//        //when
-//        List<String> collect = value.stream().map(String::toUpperCase).collect(Collectors.toList());
-//
-//        //then
-//        assertThat(collect).hasSameElementsAs(List.of("A"));
-//    }
-//
-//    @Test
-//    public void givenOptionalOfNone_whenToStream_thenShouldTreatItAsZeroElementStream() {
-//        //given
-//        Optional<String> value = Optional.empty();
-//
-//        //when
-//        List<String> collect = value.stream().map(String::toUpperCase).collect(Collectors.toList());
-//
-//        //then
-//        assertThat(collect).isEmpty();
-//    }
-//
-//    @Test
-//    public void givenOptional_whenPresent_thenShouldExecuteProperCallback() {
-//        //given
-//        Optional<String> value = Optional.of("properValue");
-//        AtomicInteger successCounter = new AtomicInteger(0);
-//        AtomicInteger onEmptyOptionalCounter = new AtomicInteger(0);
-//
-//        //when
-//        value.ifPresentOrElse((v) -> successCounter.incrementAndGet(), onEmptyOptionalCounter::incrementAndGet);
-//
-//        //then
-//        assertThat(successCounter.get()).isEqualTo(1);
-//        assertThat(onEmptyOptionalCounter.get()).isEqualTo(0);
-//    }
-//
-//    @Test
-//    public void givenOptional_whenNotPresent_thenShouldExecuteProperCallback() {
-//        //given
-//        Optional<String> value = Optional.empty();
-//        AtomicInteger successCounter = new AtomicInteger(0);
-//        AtomicInteger onEmptyOptionalCounter = new AtomicInteger(0);
-//
-//        //when
-//        value.ifPresentOrElse((v) -> successCounter.incrementAndGet(), onEmptyOptionalCounter::incrementAndGet);
-//
-//        //then
-//        assertThat(successCounter.get()).isEqualTo(0);
-//        assertThat(onEmptyOptionalCounter.get()).isEqualTo(1);
-//    }
-//
-//    @Test
-//    public void givenOptional_whenPresent_thenShouldTakeAValueFromIt() {
-//        //given
-//        String expected = "properValue";
-//        Optional<String> value = Optional.of(expected);
-//        Optional<String> defaultValue = Optional.of("default");
-//
-//        //when
-//        Optional<String> result = value.or(() -> defaultValue);
-//
-//        //then
-//        assertThat(result.get()).isEqualTo(expected);
-//    }
-//
-//    @Test
-//    public void givenOptional_whenEmpty_thenShouldTakeAValueFromOr() {
-//        //given
-//        String defaultString = "default";
-//        Optional<String> value = Optional.empty();
-//        Optional<String> defaultValue = Optional.of(defaultString);
-//
-//        //when
-//        Optional<String> result = value.or(() -> defaultValue);
-//
-//        //then
-//        assertThat(result.get()).isEqualTo(defaultString);
-//    }
-//}
+
+public class Java9OptionalUnitTest {
+
+    @Test
+    public void givenOptionalOfSome_whenToStream_thenShouldTreatItAsOneElementStream() {
+        //given
+        Optional<String> value = Optional.of("a");
+
+        //when
+        List<String> collect = value.stream().map(String::toUpperCase).collect(Collectors.toList());
+
+        //then
+        assertThat(collect).hasSameElementsAs(List.of("A"));
+    }
+
+    @Test
+    public void givenOptionalOfNone_whenToStream_thenShouldTreatItAsZeroElementStream() {
+        //given
+        Optional<String> value = Optional.empty();
+
+        //when
+        List<String> collect = value.stream().map(String::toUpperCase).collect(Collectors.toList());
+
+        //then
+        assertThat(collect).isEmpty();
+    }
+
+    @Test
+    public void givenOptional_whenPresent_thenShouldExecuteProperCallback() {
+        //given
+        Optional<String> value = Optional.of("properValue");
+        AtomicInteger successCounter = new AtomicInteger(0);
+        AtomicInteger onEmptyOptionalCounter = new AtomicInteger(0);
+
+        //when
+        value.ifPresentOrElse((v) -> successCounter.incrementAndGet(), onEmptyOptionalCounter::incrementAndGet);
+
+        //then
+        assertThat(successCounter.get()).isEqualTo(1);
+        assertThat(onEmptyOptionalCounter.get()).isEqualTo(0);
+    }
+
+    @Test
+    public void givenOptional_whenNotPresent_thenShouldExecuteProperCallback() {
+        //given
+        Optional<String> value = Optional.empty();
+        AtomicInteger successCounter = new AtomicInteger(0);
+        AtomicInteger onEmptyOptionalCounter = new AtomicInteger(0);
+
+        //when
+        value.ifPresentOrElse((v) -> successCounter.incrementAndGet(), onEmptyOptionalCounter::incrementAndGet);
+
+        //then
+        assertThat(successCounter.get()).isEqualTo(0);
+        assertThat(onEmptyOptionalCounter.get()).isEqualTo(1);
+    }
+
+    @Test
+    public void givenOptional_whenPresent_thenShouldTakeAValueFromIt() {
+        //given
+        String expected = "properValue";
+        Optional<String> value = Optional.of(expected);
+        Optional<String> defaultValue = Optional.of("default");
+
+        //when
+        Optional<String> result = value.or(() -> defaultValue);
+
+        //then
+        assertThat(result.get()).isEqualTo(expected);
+    }
+
+    @Test
+    public void givenOptional_whenEmpty_thenShouldTakeAValueFromOr() {
+        //given
+        String defaultString = "default";
+        Optional<String> value = Optional.empty();
+        Optional<String> defaultValue = Optional.of(defaultString);
+
+        //when
+        Optional<String> result = value.or(() -> defaultValue);
+
+        //then
+        assertThat(result.get()).isEqualTo(defaultString);
+    }
+}

core-java-modules/core-java-os-2/pom.xml

@@ -3,8 +3,8 @@
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-    <artifactId>core-java-os</artifactId>
-    <name>core-java-os</name>
+    <artifactId>core-java-os-2</artifactId>
+    <name>core-java-os-2</name>
     <packaging>jar</packaging>
 
     <parent>

core-java-modules/core-java-records/README.md

@@ -1,2 +1,3 @@
 ## Relevant Articles
 - [Overriding hashCode() And equals() For Records](https://www.baeldung.com/java-override-hashcode-equals-records)
+- [Optional as a Record Parameter in Java](https://www.baeldung.com/java-record-optional-param)

core-java-modules/core-java-reflection/pom.xml

@@ -52,7 +52,6 @@
         <source.version>1.8</source.version>
         <target.version>1.8</target.version>
         <reflections.version>0.10.2</reflections.version>
-        <commons-lang3.version>3.12.0</commons-lang3.version>
     </properties>
 
 </project>

core-java-modules/core-java-security-2/pom.xml

@@ -21,7 +21,7 @@
         </dependency>
         <dependency>
             <groupId>org.bouncycastle</groupId>
-            <artifactId>bcprov-jdk15on</artifactId>
+            <artifactId>bcprov-jdk18on</artifactId>
             <version>${bouncycastle.version}</version>
         </dependency>
         <!-- https://mvnrepository.com/artifact/javax.xml.bind/jaxb-api -->
@@ -33,8 +33,8 @@
     </dependencies>
 
     <properties>
-        <bouncycastle.version>1.60</bouncycastle.version>
-        <commons-codec.version>1.11</commons-codec.version>
+        <bouncycastle.version>1.76</bouncycastle.version>
+        <commons-codec.version>1.16.0</commons-codec.version>
         <jaxb-api.version>2.3.1</jaxb-api.version>
     </properties>
 

core-java-modules/core-java-security-3/pom.xml

@@ -21,7 +21,7 @@
         </dependency>
         <dependency>
             <groupId>org.bouncycastle</groupId>
-            <artifactId>bcprov-jdk15on</artifactId>
+            <artifactId>bcprov-jdk18on</artifactId>
             <version>${bouncycastle.version}</version>
         </dependency>
         <!-- https://mvnrepository.com/artifact/javax.xml.bind/jaxb-api -->
@@ -43,8 +43,8 @@
     </dependencies>
 
     <properties>
-        <bouncycastle.version>1.70</bouncycastle.version>
-        <commons-codec.version>1.15</commons-codec.version>
+        <bouncycastle.version>1.76</bouncycastle.version>
+        <commons-codec.version>1.16.0</commons-codec.version>
         <jaxb-api.version>2.3.1</jaxb-api.version>
         <spring-security-crypto.version>6.0.3</spring-security-crypto.version>
     </properties>

core-java-modules/core-java-security-4/pom.xml

@@ -16,7 +16,7 @@
     <dependencies>
         <dependency>
             <groupId>org.bouncycastle</groupId>
-            <artifactId>bcpkix-jdk15on</artifactId>
+            <artifactId>bcpkix-jdk18on</artifactId>
             <version>${bouncycastle.version}</version>
         </dependency>
         <dependency>
@@ -27,7 +27,7 @@
     </dependencies>
 
     <properties>
-        <bouncycastle.version>1.70</bouncycastle.version>
+        <bouncycastle.version>1.76</bouncycastle.version>
         <cryptacular.version>1.2.6</cryptacular.version>
     </properties>
 

core-java-modules/core-java-streams-5/README.md

@@ -5,3 +5,5 @@
 - [Streams vs. Loops in Java](https://www.baeldung.com/java-streams-vs-loops)
 - [Partition a Stream in Java](https://www.baeldung.com/java-partition-stream)
 - [Taking Every N-th Element from Finite and Infinite Streams in Java](https://www.baeldung.com/java-nth-element-finite-infinite-streams)
+- [Modifying Objects Within Stream While Iterating](https://www.baeldung.com/java-stream-modify-objects-during-iteration)
+- [Convert a Stream into a Map or Multimap in Java](https://www.baeldung.com/java-convert-stream-map-multimap)

core-java-modules/core-java-streams-5/pom.xml

@@ -77,7 +77,6 @@
         <maven.compiler.source>12</maven.compiler.source>
         <maven.compiler.target>12</maven.compiler.target>
         <vavr.version>0.10.2</vavr.version>
-        <guava.version>32.1.2-jre</guava.version>
     </properties>
 
 </project>

core-java-modules/core-java-streams-5/src/main/java/com/baledung/modifystream/entity/ImmutablePerson.java

@@ -0,0 +1,25 @@
+package com.baledung.modifystream.entity;
+
+public class ImmutablePerson {
+
+    private String name;
+    private String email;
+
+    public ImmutablePerson(String name, String email) {
+        this.name = name;
+        this.email = email;
+    }
+
+    public ImmutablePerson withEmail(String email) {
+
+        return new ImmutablePerson(this.name, email);
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+}

core-java-modules/core-java-streams-5/src/main/java/com/baledung/modifystream/entity/Person.java

@@ -0,0 +1,27 @@
+package com.baledung.modifystream.entity;
+
+public class Person {
+    private String name;
+    private String email;
+
+    public Person(String name, String email) {
+        this.name = name;
+        this.email = email;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+}

core-java-modules/core-java-streams-5/src/test/java/com/baeldung/modifystream/ModifyStreamUnitTest.java

@@ -0,0 +1,132 @@
+package com.baeldung.modifystream;
+
+import com.baledung.modifystream.entity.ImmutablePerson;
+import com.baledung.modifystream.entity.Person;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.ArrayList;
+import java.util.ConcurrentModificationException;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.stream.Collectors;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class ModifyStreamUnitTest {
+    Logger logger = LoggerFactory.getLogger(ModifyStreamUnitTest.class);
+    List<Person> personList = new ArrayList<Person>();
+    List<ImmutablePerson> immutablePersonList = new ArrayList<ImmutablePerson>();
+
+    @BeforeEach
+    void prepare() {
+        Person person1 = new Person("John", "john@gmail.com");
+        Person person2 = new Person("Peter", "peter@gmail.com");
+        Person person3 = new Person("Mary", "mary@gmail.com");
+        Person person4 = new Person("William", "william@gmail.com");
+
+        personList.add(person1);
+        personList.add(person2);
+        personList.add(person3);
+        personList.add(person4);
+    }
+
+    @BeforeEach
+    void prepareImmutablePerson() {
+        ImmutablePerson immutablePerson1 = new ImmutablePerson("John", "john@gmail.com");
+        ImmutablePerson immutablePerson2 = new ImmutablePerson("Peter", "peter@gmail.com");
+        ImmutablePerson immutablePerson3 = new ImmutablePerson("Mary", "mary@gmail.com");
+        ImmutablePerson immutablePerson4 = new ImmutablePerson("William", "william@gmail.com");
+
+        immutablePersonList.add(immutablePerson1);
+        immutablePersonList.add(immutablePerson2);
+        immutablePersonList.add(immutablePerson3);
+        immutablePersonList.add(immutablePerson4);
+    }
+
+    @Test
+    void givenPersonList_whenRemoveWhileIterating_thenThrowException() {
+        assertThrows(NullPointerException.class, () -> {
+            personList.stream().forEach(e -> {
+                if(e.getName().equals("John")) {
+                    personList.remove(e);
+                }
+            });
+        });
+    }
+
+    @Test
+    void givenPersonList_whenRemoveWhileIteratingWithForEach_thenThrowException() {
+        assertThrows(ConcurrentModificationException.class, () -> {
+            personList.forEach(e -> {
+                if(e.getName().equals("John")) {
+                    personList.remove(e);
+                }
+            });
+        });
+    }
+
+    @Test
+    void givenPersonList_whenRemoveWhileIterating_thenPersonRemoved() {
+        assertEquals(4, personList.size());
+
+        CopyOnWriteArrayList<Person> cps = new CopyOnWriteArrayList<>(personList);
+        cps.stream().forEach(e -> {
+            if(e.getName().equals("John")) {
+                cps.remove(e);
+            }
+        });
+
+        assertEquals(3, cps.size());
+    }
+
+
+    @Test
+    void givenPersonList_whenRemovePersonWithFilter_thenPersonRemoved() {
+        assertEquals(4, personList.size());
+
+        List<Person> newPersonList = personList.stream()
+          .filter(e -> !e.getName().equals("John"))
+          .collect(Collectors.toList());
+
+        assertEquals(3, newPersonList.size());
+    }
+
+    @Test
+    void givenPersonList_whenUpdatePersonEmailByInterferingWithForEach_thenPersonEmailUpdated() {
+        personList.stream().forEach(e -> e.setEmail(e.getEmail().toUpperCase()));
+
+        personList.forEach(e -> assertEquals(e.getEmail(), e.getEmail().toUpperCase()));
+    }
+
+    @Test
+    void givenPersonList_whenUpdatePersonEmailWithMapMethod_thenPersonEmailUpdated() {
+        List<Person> newPersonList = personList.stream()
+          .map(e -> new Person(e.getName(), e.getEmail().toUpperCase()))
+          .collect(Collectors.toList());
+
+        newPersonList.forEach(e -> assertEquals(e.getEmail(), e.getEmail().toUpperCase()));
+    }
+
+    @Test
+    void givenPersonList_whenUpdateImmutablePersonEmailWithMapMethod_thenPersonEmailUpdated() {
+        List<ImmutablePerson> newImmutablePersonList = immutablePersonList.stream()
+          .map(e -> e.withEmail(e.getEmail().toUpperCase()))
+          .collect(Collectors.toList());
+
+        newImmutablePersonList.forEach(e -> assertEquals(e.getEmail(), e.getEmail().toUpperCase()));
+    }
+
+    @Test
+    void givenPersonList_whenUpdatePersonEmailByInterferingWithPeek_thenPersonEmailUpdated() {
+        personList.stream()
+          .peek(e -> e.setEmail(e.getEmail().toUpperCase()))
+          .collect(Collectors.toList());
+
+        personList.forEach(e -> assertEquals(e.getEmail(), e.getEmail().toUpperCase()));
+    }
+
+}

core-java-modules/core-java-streams-5/src/test/java/com/baeldung/nosuchelementexception/NoSuchElementExceptionStreamUnitTest.java

@@ -0,0 +1,62 @@
+package com.baeldung.nosuchelementexception;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.Optional;
+
+import org.junit.Test;
+
+public class NoSuchElementExceptionStreamUnitTest {
+
+    @Test(expected = NoSuchElementException.class)
+    public void givenEmptyOptional_whenCallingGetMethod_thenThrowNoSuchElementException() {
+        List<String> names = List.of("William", "Amelia", "Albert", "Philip");
+        Optional<String> emptyOptional = names.stream()
+          .filter(name -> name.equals("Emma"))
+          .findFirst();
+
+        emptyOptional.get();
+    }
+
+    @Test
+    public void givenEmptyOptional_whenUsingIsPresentMethod_thenReturnDefault() {
+        List<String> names = List.of("Tyler", "Amelia", "James", "Emma");
+        Optional<String> emptyOptional = names.stream()
+          .filter(name -> name.equals("Lucas"))
+          .findFirst();
+
+        String name = "unknown";
+        if (emptyOptional.isPresent()) {
+            name = emptyOptional.get();
+        }
+
+        assertEquals("unknown", name);
+    }
+
+    @Test
+    public void givenEmptyOptional_whenUsingOrElseMethod_thenReturnDefault() {
+        List<String> names = List.of("Nicholas", "Justin", "James");
+        Optional<String> emptyOptional = names.stream()
+          .filter(name -> name.equals("Lucas"))
+          .findFirst();
+
+        String name = emptyOptional.orElse("unknown");
+
+        assertEquals("unknown", name);
+    }
+
+    @Test
+    public void givenEmptyOptional_whenUsingOrElseGetMethod_thenReturnDefault() {
+        List<String> names = List.of("Thomas", "Catherine", "David", "Olivia");
+        Optional<String> emptyOptional = names.stream()
+          .filter(name -> name.equals("Liam"))
+          .findFirst();
+
+        String name = emptyOptional.orElseGet(() -> "unknown");
+
+        assertEquals("unknown", name);
+    }
+
+}

core-java-modules/core-java-streams-5/src/test/java/com/baeldung/streamtomapandmultimap/StreamToMapAndMultiMapUnitTest.java

@@ -1,6 +1,7 @@
 package com.baeldung.streamtomapandmultimap;
 
-import com.google.common.collect.LinkedHashMultimap;
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.ListMultimap;
 import org.junit.Test;
 
 import java.util.*;
@@ -32,16 +33,16 @@ public class StreamToMapAndMultiMapUnitTest {
     public void givenStringStream_whenConvertingToMultimap_thenExpectedMultimapIsGenerated() {
         Stream<String> stringStream = Stream.of("one", "two", "three", "two");
 
-        LinkedHashMultimap<Object, Object> multimap = LinkedHashMultimap.create();
+        ListMultimap<String, String> multimap = stringStream.collect(
+                ArrayListMultimap::create,
+                (map, element) -> map.put(element, element),
+                ArrayListMultimap::putAll
+        );
 
-        stringStream.collect(Collectors.groupingBy(
-                s -> s,
-                Collectors.mapping(s -> s, Collectors.toList())
-        )).forEach((key, value) -> multimap.putAll(key, value));
-
-        LinkedHashMultimap<Object, Object> expectedMultimap = LinkedHashMultimap.create();
+        ListMultimap<String, String> expectedMultimap = ArrayListMultimap.create();
         expectedMultimap.put("one", "one");
         expectedMultimap.put("two", "two");
+        expectedMultimap.put("two", "two");
         expectedMultimap.put("three", "three");
 
         assertEquals(expectedMultimap, multimap);
@@ -97,4 +98,4 @@ public class StreamToMapAndMultiMapUnitTest {
 
         assertEquals(expectedMap, resultMap);
     }
-}
+}

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/entities/User.java

@@ -4,6 +4,7 @@ public class User {
 
     private final String name;
     private final int age;
+    private final Rating rating = new Rating();
 
     public User(String name, int age) {
         this.name = name;
@@ -17,7 +18,11 @@ public class User {
     public int getAge() {
         return age;
     }
-    
+
+    public Rating getRating() {
+        return rating;
+    }
+
     @Override
     public String toString() {
         return "User{" + "name=" + name + ", age=" + age + '}';

core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/collectors/Java8CollectorsUnitTest.java

@@ -3,6 +3,7 @@ package com.baeldung.streams.collectors;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
+
 import org.junit.Test;
 
 import java.util.*;
@@ -23,142 +24,159 @@ public class Java8CollectorsUnitTest {
     private final List<String> listWithDuplicates = Arrays.asList("a", "bb", "c", "d", "bb");
 
     @Test
-    public void whenCollectingToList_shouldCollectToList() throws Exception {
-        final List<String> result = givenList.stream().collect(toList());
+    public void whenCollectingToList_shouldCollectToList() {
+        final List<String> result = givenList.stream()
+            .collect(toList());
 
         assertThat(result).containsAll(givenList);
     }
 
     @Test
     public void whenCollectingToUnmodifiableList_shouldCollectToUnmodifiableList() {
-        final List<String> result = givenList.stream().collect(toUnmodifiableList());
+        final List<String> result = givenList.stream()
+            .collect(toUnmodifiableList());
 
-        assertThatThrownBy(() -> result.add("foo"))
-          .isInstanceOf(UnsupportedOperationException.class);
+        assertThatThrownBy(() -> result.add("foo")).isInstanceOf(UnsupportedOperationException.class);
     }
 
     @Test
-    public void whenCollectingToSet_shouldCollectToSet() throws Exception {
-        final Set<String> result = givenList.stream().collect(toSet());
+    public void whenCollectingToSet_shouldCollectToSet() {
+        final Set<String> result = givenList.stream()
+            .collect(toSet());
 
         assertThat(result).containsAll(givenList);
     }
 
     @Test
     public void whenCollectingToUnmodifiableSet_shouldCollectToUnmodifiableSet() {
-        final Set<String> result = givenList.stream().collect(toUnmodifiableSet());
+        final Set<String> result = givenList.stream()
+            .collect(toUnmodifiableSet());
 
-        assertThatThrownBy(() -> result.add("foo"))
-          .isInstanceOf(UnsupportedOperationException.class);
+        assertThatThrownBy(() -> result.add("foo")).isInstanceOf(UnsupportedOperationException.class);
     }
 
     @Test
     public void givenContainsDuplicateElements_whenCollectingToSet_shouldAddDuplicateElementsOnlyOnce() throws Exception {
-        final Set<String> result = listWithDuplicates.stream().collect(toSet());
+        final Set<String> result = listWithDuplicates.stream()
+            .collect(toSet());
 
         assertThat(result).hasSize(4);
     }
 
     @Test
-    public void whenCollectingToCollection_shouldCollectToCollection() throws Exception {
-        final List<String> result = givenList.stream().collect(toCollection(LinkedList::new));
+    public void whenCollectingToCollection_shouldCollectToCollection() {
+        final List<String> result = givenList.stream()
+            .collect(toCollection(LinkedList::new));
 
-        assertThat(result).containsAll(givenList).isInstanceOf(LinkedList.class);
+        assertThat(result).containsAll(givenList)
+            .isInstanceOf(LinkedList.class);
     }
 
     @Test
-    public void whenCollectingToImmutableCollection_shouldThrowException() throws Exception {
+    public void whenCollectingToImmutableCollection_shouldThrowException() {
         assertThatThrownBy(() -> {
-            givenList.stream().collect(toCollection(ImmutableList::of));
+            givenList.stream()
+                .collect(toCollection(ImmutableList::of));
         }).isInstanceOf(UnsupportedOperationException.class);
 
     }
 
     @Test
-    public void whenCollectingToMap_shouldCollectToMap() throws Exception {
-        final Map<String, Integer> result = givenList.stream().collect(toMap(Function.identity(), String::length));
+    public void whenCollectingToMap_shouldCollectToMap() {
+        final Map<String, Integer> result = givenList.stream()
+            .collect(toMap(Function.identity(), String::length));
 
-        assertThat(result).containsEntry("a", 1).containsEntry("bb", 2).containsEntry("ccc", 3).containsEntry("dd", 2);
+        assertThat(result).containsEntry("a", 1)
+            .containsEntry("bb", 2)
+            .containsEntry("ccc", 3)
+            .containsEntry("dd", 2);
     }
 
     @Test
     public void whenCollectingToUnmodifiableMap_shouldCollectToUnmodifiableMap() {
         final Map<String, Integer> result = givenList.stream()
-          .collect(toUnmodifiableMap(Function.identity(), String::length));
+            .collect(toUnmodifiableMap(Function.identity(), String::length));
 
-        assertThatThrownBy(() -> result.put("foo", 3))
-                .isInstanceOf(UnsupportedOperationException.class);
+        assertThatThrownBy(() -> result.put("foo", 3)).isInstanceOf(UnsupportedOperationException.class);
     }
 
     @Test
     public void whenCollectingToMapwWithDuplicates_shouldCollectToMapMergingTheIdenticalItems() throws Exception {
-        final Map<String, Integer> result = listWithDuplicates.stream().collect(
-          toMap(
-            Function.identity(),
-            String::length,
-            (item, identicalItem) -> item
-          )
-        );
+        final Map<String, Integer> result = listWithDuplicates.stream()
+            .collect(toMap(Function.identity(), String::length, (item, identicalItem) -> item));
 
-        assertThat(result).containsEntry("a", 1).containsEntry("bb", 2).containsEntry("c", 1).containsEntry("d", 1);
+        assertThat(result).containsEntry("a", 1)
+            .containsEntry("bb", 2)
+            .containsEntry("c", 1)
+            .containsEntry("d", 1);
     }
 
     @Test
-    public void givenContainsDuplicateElements_whenCollectingToMap_shouldThrowException() throws Exception {
+    public void givenContainsDuplicateElements_whenCollectingToMap_shouldThrowException() {
         assertThatThrownBy(() -> {
-            listWithDuplicates.stream().collect(toMap(Function.identity(), String::length));
+            listWithDuplicates.stream()
+                .collect(toMap(Function.identity(), String::length));
         }).isInstanceOf(IllegalStateException.class);
     }
 
     @Test
-    public void whenCollectingAndThen_shouldCollect() throws Exception {
-        final List<String> result = givenList.stream().collect(collectingAndThen(toList(), ImmutableList::copyOf));
+    public void whenCollectingAndThen_shouldCollect() {
+        final List<String> result = givenList.stream()
+            .collect(collectingAndThen(toList(), ImmutableList::copyOf));
 
-        assertThat(result).containsAll(givenList).isInstanceOf(ImmutableList.class);
+        assertThat(result).containsAll(givenList)
+            .isInstanceOf(ImmutableList.class);
     }
 
     @Test
-    public void whenJoining_shouldJoin() throws Exception {
-        final String result = givenList.stream().collect(joining());
+    public void whenJoining_shouldJoin() {
+        final String result = givenList.stream()
+            .collect(joining());
 
         assertThat(result).isEqualTo("abbcccdd");
     }
 
     @Test
-    public void whenJoiningWithSeparator_shouldJoinWithSeparator() throws Exception {
-        final String result = givenList.stream().collect(joining(" "));
+    public void whenJoiningWithSeparator_shouldJoinWithSeparator() {
+        final String result = givenList.stream()
+            .collect(joining(" "));
 
         assertThat(result).isEqualTo("a bb ccc dd");
     }
 
     @Test
-    public void whenJoiningWithSeparatorAndPrefixAndPostfix_shouldJoinWithSeparatorPrePost() throws Exception {
-        final String result = givenList.stream().collect(joining(" ", "PRE-", "-POST"));
+    public void whenJoiningWithSeparatorAndPrefixAndPostfix_shouldJoinWithSeparatorPrePost() {
+        final String result = givenList.stream()
+            .collect(joining(" ", "PRE-", "-POST"));
 
         assertThat(result).isEqualTo("PRE-a bb ccc dd-POST");
     }
 
     @Test
-    public void whenPartitioningBy_shouldPartition() throws Exception {
-        final Map<Boolean, List<String>> result = givenList.stream().collect(partitioningBy(s -> s.length() > 2));
+    public void whenPartitioningBy_shouldPartition() {
+        final Map<Boolean, List<String>> result = givenList.stream()
+            .collect(partitioningBy(s -> s.length() > 2));
 
-        assertThat(result).containsKeys(true, false).satisfies(booleanListMap -> {
-            assertThat(booleanListMap.get(true)).contains("ccc");
+        assertThat(result).containsKeys(true, false)
+            .satisfies(booleanListMap -> {
+                assertThat(booleanListMap.get(true)).contains("ccc");
 
-            assertThat(booleanListMap.get(false)).contains("a", "bb", "dd");
-        });
+                assertThat(booleanListMap.get(false)).contains("a", "bb", "dd");
+            });
     }
 
     @Test
-    public void whenCounting_shouldCount() throws Exception {
-        final Long result = givenList.stream().collect(counting());
+    public void whenCounting_shouldCount() {
+        final Long result = givenList.stream()
+            .collect(counting());
 
         assertThat(result).isEqualTo(4);
     }
 
     @Test
-    public void whenSummarizing_shouldSummarize() throws Exception {
-        final DoubleSummaryStatistics result = givenList.stream().collect(summarizingDouble(String::length));
+    public void whenSummarizing_shouldSummarize() {
+        final DoubleSummaryStatistics result = givenList.stream()
+            .collect(summarizingDouble(String::length));
 
         assertThat(result.getAverage()).isEqualTo(2);
         assertThat(result.getCount()).isEqualTo(4);
@@ -168,38 +186,47 @@ public class Java8CollectorsUnitTest {
     }
 
     @Test
-    public void whenAveraging_shouldAverage() throws Exception {
-        final Double result = givenList.stream().collect(averagingDouble(String::length));
+    public void whenAveraging_shouldAverage() {
+        final Double result = givenList.stream()
+            .collect(averagingDouble(String::length));
 
         assertThat(result).isEqualTo(2);
     }
 
     @Test
-    public void whenSumming_shouldSum() throws Exception {
-        final Double result = givenList.stream().filter(i -> true).collect(summingDouble(String::length));
+    public void whenSumming_shouldSum() {
+        final Double result = givenList.stream()
+            .collect(summingDouble(String::length));
 
         assertThat(result).isEqualTo(8);
     }
 
     @Test
-    public void whenMaxingBy_shouldMaxBy() throws Exception {
-        final Optional<String> result = givenList.stream().collect(maxBy(Comparator.naturalOrder()));
+    public void whenMaxingBy_shouldMaxBy() {
+        final Optional<String> result = givenList.stream()
+            .collect(maxBy(Comparator.naturalOrder()));
 
-        assertThat(result).isPresent().hasValue("dd");
+        assertThat(result).isPresent()
+            .hasValue("dd");
     }
 
     @Test
-    public void whenGroupingBy_shouldGroupBy() throws Exception {
-        final Map<Integer, Set<String>> result = givenList.stream().collect(groupingBy(String::length, toSet()));
+    public void whenGroupingBy_shouldGroupBy() {
+        final Map<Integer, Set<String>> result = givenList.stream()
+            .collect(groupingBy(String::length, toSet()));
 
-        assertThat(result).containsEntry(1, newHashSet("a")).containsEntry(2, newHashSet("bb", "dd")).containsEntry(3, newHashSet("ccc"));
+        assertThat(result).containsEntry(1, newHashSet("a"))
+            .containsEntry(2, newHashSet("bb", "dd"))
+            .containsEntry(3, newHashSet("ccc"));
     }
 
     @Test
-    public void whenCreatingCustomCollector_shouldCollect() throws Exception {
-        final ImmutableSet<String> result = givenList.stream().collect(toImmutableSet());
+    public void whenCreatingCustomCollector_shouldCollect() {
+        final ImmutableSet<String> result = givenList.stream()
+            .collect(toImmutableSet());
 
-        assertThat(result).isInstanceOf(ImmutableSet.class).contains("a", "bb", "ccc", "dd");
+        assertThat(result).isInstanceOf(ImmutableSet.class)
+            .contains("a", "bb", "ccc", "dd");
 
     }
 

core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/reduce/StreamReduceManualTest.java

@@ -1,15 +1,18 @@
-package com.baeldung.streamreduce.tests;
+package com.baeldung.streams.reduce;
+
+import static org.assertj.core.api.Assertions.assertThat;
 
-import com.baeldung.streamreduce.entities.Rating;
-import com.baeldung.streamreduce.entities.Review;
-import com.baeldung.streamreduce.entities.User;
-import com.baeldung.streamreduce.utilities.NumberUtils;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
-import static org.assertj.core.api.Assertions.assertThat;
+
 import org.junit.Test;
 
+import com.baeldung.streams.reduce.entities.Rating;
+import com.baeldung.streams.reduce.entities.Review;
+import com.baeldung.streams.reduce.entities.User;
+import com.baeldung.streams.reduce.utilities.NumberUtils;
+
 public class StreamReduceManualTest {
 
     @Test