Merge pull request #69 from eugenp/master

update
2020-08-29 23:11:23 +02:00
parent 7784219a2e 1e167f7fa4
commit 9541b56c5e
578 changed files with 3383 additions and 1263 deletions
@@ -3,6 +3,7 @@
 This module contains articles about searching algorithms.

 ### Relevant articles:
+
 - [Binary Search Algorithm in Java](https://www.baeldung.com/java-binary-search)
 - [Depth First Search in Java](https://www.baeldung.com/java-depth-first-search)
 - [Interpolation Search in Java](https://www.baeldung.com/java-interpolation-search)
@@ -11,3 +12,4 @@ This module contains articles about searching algorithms.
 - [Monte Carlo Tree Search for Tic-Tac-Toe Game](https://www.baeldung.com/java-monte-carlo-tree-search)
 - [Range Search Algorithm in Java](https://www.baeldung.com/java-range-search)
 - [Fast Pattern Matching of Strings Using Suffix Tree](https://www.baeldung.com/java-pattern-matching-suffix-tree)
+- [Find the Kth Smallest Element in Two Sorted Arrays](https://www.baeldung.com/java-kth-smallest-element-in-sorted-arrays)
@@ -3,9 +3,11 @@
 This module contains articles about Apache POI

 ### Relevant Articles:
+
 - [Microsoft Word Processing in Java with Apache POI](https://www.baeldung.com/java-microsoft-word-with-apache-poi)
 - [Working with Microsoft Excel in Java](https://www.baeldung.com/java-microsoft-excel)
 - [Creating a MS PowerPoint Presentation in Java](https://www.baeldung.com/apache-poi-slideshow)
 - [Merge Cells in Excel Using Apache POI](https://www.baeldung.com/java-apache-poi-merge-cells)
 - [Get String Value of Excel Cell with Apache POI](https://www.baeldung.com/java-apache-poi-cell-string-value)
 - [Read Excel Cell Value Rather Than Formula With Apache POI](https://www.baeldung.com/apache-poi-read-cell-value-formula)
+- [Setting Formulas in Excel with Apache POI](https://www.baeldung.com/java-apache-poi-set-formulas)
@@ -1,8 +1,8 @@
 <?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="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">
    <modelVersion>4.0.0</modelVersion>
    <artifactId>cdi</artifactId>
    <version>1.0-SNAPSHOT</version>
@@ -10,9 +10,9 @@

    <parent>
        <groupId>com.baeldung</groupId>
-        <artifactId>parent-spring-4</artifactId>
+        <artifactId>parent-spring-5</artifactId>
        <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../parent-spring-4</relativePath>
+        <relativePath>../parent-spring-5</relativePath>
    </parent>

    <dependencies>
@@ -26,28 +26,22 @@
            <artifactId>weld-se-core</artifactId>
            <version>${weld-se-core.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.hamcrest</groupId>
-            <artifactId>hamcrest</artifactId>
-            <version>${hamcrest.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.assertj</groupId>
            <artifactId>assertj-core</artifactId>
            <version>${assertj-core.version}</version>
            <scope>test</scope>
        </dependency>
-        <dependency>
-            <groupId>org.springframework</groupId>
-            <artifactId>spring-context</artifactId>
-            <version>${spring.version}</version>
-        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>${aspectjweaver.version}</version>
        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-context</artifactId>
+            <version>${spring.version}</version>
+        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
@@ -61,7 +55,6 @@
        <weld-se-core.version>3.0.5.Final</weld-se-core.version>
        <aspectjweaver.version>1.9.2</aspectjweaver.version>
        <assertj-core.version>3.10.0</assertj-core.version>
-        <spring.version>5.1.2.RELEASE</spring.version>
    </properties>

 </project>
@@ -9,3 +9,4 @@ This module contains articles about Java 10 core features
 - [Copy a List to Another List in Java](http://www.baeldung.com/java-copy-list-to-another)
 - [Deep Dive Into the New Java JIT Compiler – Graal](https://www.baeldung.com/graal-java-jit-compiler)
 - [Copying Sets in Java](https://www.baeldung.com/java-copy-sets)
+- [Converting between a List and a Set in Java](https://www.baeldung.com/convert-list-to-set-and-set-to-list)
@@ -1,22 +1,29 @@
 <?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="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">
    <modelVersion>4.0.0</modelVersion>
    <artifactId>core-java-10</artifactId>
    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-10</name>
    <packaging>jar</packaging>
-    <url>http://maven.apache.org</url>

    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-        <relativePath>../../</relativePath>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../</relativePath>
    </parent>

+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
+    </dependencies>
+
    <build>
        <plugins>
            <plugin>
@@ -34,6 +41,7 @@
    <properties>
        <maven.compiler.source.version>10</maven.compiler.source.version>
        <maven.compiler.target.version>10</maven.compiler.target.version>
+        <commons-collections4.version>4.1</commons-collections4.version>
    </properties>

 </project>
@@ -0,0 +1,68 @@
+package com.baeldung.java10.collections.conversion;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+import org.apache.commons.collections4.CollectionUtils;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+public class ListSetConversionUnitTest {
+
+    // Set -> List; List -> Set
+
+    @Test
+    public final void givenUsingCoreJava_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final List<Integer> targetList = new ArrayList<>(sourceSet);
+    }
+
+    @Test
+    public final void givenUsingCoreJava_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+        final Set<Integer> targetSet = new HashSet<>(sourceList);
+    }
+
+    @Test
+    public void givenUsingJava10_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final List<Integer> targetList = List.copyOf(sourceSet);
+    }
+
+    @Test
+    public void givenUsingJava10_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+        final Set<Integer> targetSet = Set.copyOf(sourceList);
+    }
+
+    @Test
+    public final void givenUsingGuava_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final List<Integer> targetList = Lists.newArrayList(sourceSet);
+    }
+
+    @Test
+    public final void givenUsingGuava_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+        final Set<Integer> targetSet = Sets.newHashSet(sourceList);
+    }
+
+    @Test
+    public final void givenUsingCommonsCollections_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+
+        final Set<Integer> targetSet = new HashSet<>(6);
+        CollectionUtils.addAll(targetSet, sourceList);
+    }
+
+    @Test
+    public final void givenUsingCommonsCollections_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+
+        final List<Integer> targetList = new ArrayList<>(6);
+        CollectionUtils.addAll(targetList, sourceSet);
+    }
+}
@@ -10,5 +10,6 @@ public class CopyListServiceUnitTest {
    @Test(expected = UnsupportedOperationException.class)
    public void whenModifyCopyOfList_thenThrowsException() {
        List<Integer> copyList = List.copyOf(Arrays.asList(1, 2, 3, 4));
+        copyList.add(4);
    }
 }
@@ -31,6 +31,6 @@ public class UseDateTimeFormatterUnitTest {
    public void givenALocalDate_whenFormattingWithStyleAndLocale_thenPass() {
        String result = subject.formatWithStyleAndLocale(localDateTime, FormatStyle.MEDIUM, Locale.UK);

-        assertThat(result).isEqualTo("25 Jan 2015, 06:30:00");
+        assertThat(result).isEqualTo("25-Jan-2015 06:30:00");
    }
 }
@@ -3,6 +3,7 @@ package com.baeldung.datetime;
 import static org.assertj.core.api.Assertions.assertThat;

 import java.time.LocalDateTime;
+import java.time.ZoneId;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.GregorianCalendar;
@@ -24,10 +25,11 @@ public class UseToInstantUnitTest {

    @Test
    public void givenADate_whenConvertingToLocalDate_thenAsExpected() {
-        Date givenDate = new Date(1465817690000L);
+        LocalDateTime currentDateTime = LocalDateTime.now();
+        Date givenDate = Date.from(currentDateTime.atZone(ZoneId.systemDefault()).toInstant());

        LocalDateTime localDateTime = subject.convertDateToLocalDate(givenDate);

-        assertThat(localDateTime).isEqualTo("2016-06-13T13:34:50");
+        assertThat(localDateTime).isEqualTo(currentDateTime);
    }
 }
@@ -54,7 +54,7 @@ public class UseZonedDateTimeUnitTest {
    @Test
    public void givenAStringWithTimeZone_whenParsing_thenEqualsExpected() {
        ZonedDateTime resultFromString = zonedDateTime.getZonedDateTimeUsingParseMethod("2015-05-03T10:15:30+01:00[Europe/Paris]");
-        ZonedDateTime resultFromLocalDateTime = ZonedDateTime.of(2015, 5, 3, 11, 15, 30, 0, ZoneId.of("Europe/Paris"));
+        ZonedDateTime resultFromLocalDateTime = ZonedDateTime.of(2015, 5, 3, 10, 15, 30, 0, ZoneId.of("Europe/Paris"));

        assertThat(resultFromString.getZone()).isEqualTo(ZoneId.of("Europe/Paris"));
        assertThat(resultFromLocalDateTime.getZone()).isEqualTo(ZoneId.of("Europe/Paris"));
@@ -3,7 +3,9 @@
 This module contains articles about advanced operations on arrays in Java. They assume some background knowledge with arrays in Java.

 ### Relevant Articles: 
+
 - [How to Copy an Array in Java](https://www.baeldung.com/java-array-copy)
 - [Arrays.deepEquals](https://www.baeldung.com/java-arrays-deepequals)
 - [Find Sum and Average in a Java Array](https://www.baeldung.com/java-array-sum-average)
 - [Intersection Between two Integer Arrays](https://www.baeldung.com/java-array-intersection)
+- [Comparing Arrays in Java](https://www.baeldung.com/java-comparing-arrays)
@@ -12,3 +12,4 @@
 - [Fail-Safe Iterator vs Fail-Fast Iterator](https://www.baeldung.com/java-fail-safe-vs-fail-fast-iterator)
 - [Quick Guide to the Java Stack](https://www.baeldung.com/java-stack)
 - [Convert an Array of Primitives to a List](https://www.baeldung.com/java-primitive-array-to-list)
+- [A Guide to BitSet in Java](https://www.baeldung.com/java-bitset)
@@ -10,4 +10,5 @@ This module contains articles about the Java List collection
 - [Performance Comparison of Primitive Lists in Java](https://www.baeldung.com/java-list-primitive-performance)
 - [Filtering a Java Collection by a List](https://www.baeldung.com/java-filter-collection-by-list)
 - [How to Count Duplicate Elements in Arraylist](https://www.baeldung.com/java-count-duplicate-elements-arraylist)
+- [Finding the Differences Between Two Lists in Java](https://www.baeldung.com/java-lists-difference)
 - [[<-- Prev]](/core-java-modules/core-java-collections-list-2)
@@ -21,20 +21,15 @@
            <version>${eclipse-collections.version}</version>
        </dependency>
        <dependency>
-            <groupId>net.sf.trove4j</groupId>
-            <artifactId>trove4j</artifactId>
-            <version>${trove4j.version}</version>
+            <groupId>com.carrotsearch</groupId>
+            <artifactId>hppc</artifactId>
+            <version>${hppc.version}</version>
        </dependency>
        <dependency>
            <groupId>it.unimi.dsi</groupId>
            <artifactId>fastutil</artifactId>
            <version>${fastutil.version}</version>
        </dependency>
-        <dependency>
-            <groupId>colt</groupId>
-            <artifactId>colt</artifactId>
-            <version>${colt.version}</version>
-        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
@@ -69,9 +64,8 @@
        <commons-collections4.version>4.1</commons-collections4.version>
        <avaitility.version>1.7.0</avaitility.version>
        <eclipse-collections.version>8.2.0</eclipse-collections.version>
-        <trove4j.version>3.0.2</trove4j.version>
+        <hppc.version>0.7.2</hppc.version>
        <fastutil.version>8.1.0</fastutil.version>
-        <colt.version>1.2.0</colt.version>
        <assertj.version>3.11.1</assertj.version>
    </properties>

@@ -1,29 +1,68 @@
 package com.baeldung.map.primitives;

-import cern.colt.map.AbstractIntDoubleMap;
-import cern.colt.map.OpenIntDoubleHashMap;
-import gnu.trove.map.TDoubleIntMap;
-import gnu.trove.map.hash.TDoubleIntHashMap;
+import com.carrotsearch.hppc.IntLongHashMap;
+import com.carrotsearch.hppc.IntLongScatterMap;
+import com.carrotsearch.hppc.IntObjectHashMap;
+import com.carrotsearch.hppc.IntObjectMap;
+import com.carrotsearch.hppc.IntObjectScatterMap;
+
 import it.unimi.dsi.fastutil.ints.Int2BooleanMap;
+import it.unimi.dsi.fastutil.ints.Int2BooleanMaps;
 import it.unimi.dsi.fastutil.ints.Int2BooleanOpenHashMap;
 import it.unimi.dsi.fastutil.ints.Int2BooleanSortedMap;
 import it.unimi.dsi.fastutil.ints.Int2BooleanSortedMaps;
+import it.unimi.dsi.fastutil.objects.ObjectIterator;
+
 import org.eclipse.collections.api.map.primitive.ImmutableIntIntMap;
 import org.eclipse.collections.api.map.primitive.MutableIntIntMap;
 import org.eclipse.collections.api.map.primitive.MutableObjectDoubleMap;
 import org.eclipse.collections.impl.factory.primitive.IntIntMaps;
 import org.eclipse.collections.impl.factory.primitive.ObjectDoubleMaps;

+import static java.lang.String.format;
+
+import java.math.BigDecimal;
+
 public class PrimitiveMaps {

    public static void main(String[] args) {

+        hppcMap();
        eclipseCollectionsMap();
-        troveMap();
-        coltMap();
        fastutilMap();
    }

+    private static void hppcMap() {
+        //Regular maps
+        IntLongHashMap intLongHashMap = new IntLongHashMap();
+        intLongHashMap.put(25,1L);
+        intLongHashMap.put(150,Long.MAX_VALUE);
+        intLongHashMap.put(1,0L);
+        
+        intLongHashMap.get(150);
+
+        IntObjectMap<BigDecimal> intObjectMap = new IntObjectHashMap<BigDecimal>();
+        intObjectMap.put(1, BigDecimal.valueOf(1));
+        intObjectMap.put(2, BigDecimal.valueOf(2500));
+
+        BigDecimal value = intObjectMap.get(2);
+
+        //Scatter maps
+        IntLongScatterMap intLongScatterMap = new IntLongScatterMap();
+        intLongScatterMap.put(1, 1L);
+        intLongScatterMap.put(2, -2L);
+        intLongScatterMap.put(1000,0L);    
+
+        intLongScatterMap.get(1000);
+
+        IntObjectScatterMap<BigDecimal> intObjectScatterMap = new IntObjectScatterMap<BigDecimal>();
+        intObjectScatterMap.put(1, BigDecimal.valueOf(1));
+        intObjectScatterMap.put(2, BigDecimal.valueOf(2500));
+
+        value = intObjectScatterMap.get(2);
+    }
+
+
    private static void fastutilMap() {
        Int2BooleanMap int2BooleanMap = new Int2BooleanOpenHashMap();
        int2BooleanMap.put(1, true);
@@ -32,13 +71,19 @@ public class PrimitiveMaps {

        boolean value = int2BooleanMap.get(1);

-        Int2BooleanSortedMap int2BooleanSorted = Int2BooleanSortedMaps.EMPTY_MAP;
-    }
+        //Lambda style iteration
+        Int2BooleanMaps.fastForEach(int2BooleanMap, entry -> {
+            System.out.println(String.format("Key: %d, Value: %b",entry.getIntKey(),entry.getBooleanValue()));
+        });
+
+        //Iterator based loop
+        ObjectIterator<Int2BooleanMap.Entry> iterator = Int2BooleanMaps.fastIterator(int2BooleanMap);
+        while(iterator.hasNext()) {
+            Int2BooleanMap.Entry entry = iterator.next();
+            System.out.println(String.format("Key: %d, Value: %b",entry.getIntKey(),entry.getBooleanValue()));
+
+        }

-    private static void coltMap() {
-        AbstractIntDoubleMap map = new OpenIntDoubleHashMap();
-        map.put(1, 4.5);
-        double value = map.get(1);
    }

    private static void eclipseCollectionsMap() {
@@ -53,17 +98,5 @@ public class PrimitiveMaps {
        dObject.addToValue("stability", 0.8);
    }

-    private static void troveMap() {
-        double[] doubles = new double[] {1.2, 4.5, 0.3};
-        int[] ints = new int[] {1, 4, 0};

-        TDoubleIntMap doubleIntMap = new TDoubleIntHashMap(doubles, ints);
-
-        doubleIntMap.put(1.2, 22);
-        doubleIntMap.put(4.5, 16);
-
-        doubleIntMap.adjustValue(1.2, 1);
-        doubleIntMap.adjustValue(4.5, 4);
-        doubleIntMap.adjustValue(0.3, 7);
-    }
 }
@@ -1,5 +1,8 @@
 #Core Java Console

-[Read and Write User Input in Java](http://www.baeldung.com/java-console-input-output)
-[Formatting with printf() in Java](https://www.baeldung.com/java-printstream-printf)
-[ASCII Art in Java](http://www.baeldung.com/ascii-art-in-java)
+### Relevant Articles:
+
+- [Read and Write User Input in Java](http://www.baeldung.com/java-console-input-output)
+- [Formatting with printf() in Java](https://www.baeldung.com/java-printstream-printf)
+- [ASCII Art in Java](http://www.baeldung.com/ascii-art-in-java)
+- [System.console() vs. System.out](https://www.baeldung.com/java-system-console-vs-system-out)
@@ -0,0 +1,3 @@
+### Relevant Articles:
+
+- [NoSuchMethodError in Java](https://www.baeldung.com/java-nosuchmethod-error)
@@ -0,0 +1,33 @@
+<?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">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.exceptions</groupId>
+    <artifactId>core-java-exceptions-3</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-exceptions-3</name>
+    <packaging>jar</packaging>
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../</relativePath>
+    </parent>
+
+    <dependencies>
+        <!-- test scoped -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj-core.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <!-- testing -->
+        <assertj-core.version>3.10.0</assertj-core.version>
+    </properties>
+</project>
@@ -0,0 +1,11 @@
+package com.baeldung.exceptions.nosuchmethoderror;
+
+public class MainMenu {
+    public static void main(String[] args) {
+        System.out.println("Today's Specials: " + getSpecials());
+    }
+
+    public static String getSpecials() {
+        return SpecialToday.getDesert();
+    }
+}
@@ -0,0 +1,8 @@
+package com.baeldung.exceptions.nosuchmethoderror;
+public class SpecialToday {
+    private static String desert = "Chocolate Cake";
+
+    public static String getDesert() {
+        return desert;
+    }
+}
@@ -0,0 +1,17 @@
+package com.baeldung.nullmethodparameter;
+
+public class NullParameterExample {
+    public void processSomethingNotNull(Object myParameter) {
+        if (myParameter == null) {
+            throw new IllegalArgumentException("Parameter 'myParameter' cannot be null");
+        }
+        //Do something with the parameter
+    }
+    
+    public void processSomethingElseNotNull(Object myParameter) {
+        if (myParameter == null) {
+            throw new NullPointerException("Parameter 'myParameter' cannot be null");
+        }
+        //Do something with the parameter
+    }
+}
@@ -0,0 +1,13 @@
+package com.baeldung.exceptions.nosuchmethoderror;
+
+import static org.junit.Assert.assertNotNull;
+
+import org.junit.jupiter.api.Test;
+
+class MainMenuUnitTest {
+
+    @Test
+    void whenGetSpecials_thenNotNull() {
+        assertNotNull(MainMenu.getSpecials());
+    }
+}
@@ -0,0 +1,17 @@
+package com.baeldung.nullmethodparameter;
+
+import org.junit.Test;
+
+public class NullParameterExampleUnitTest {
+    @Test(expected = IllegalArgumentException.class)
+    public void givenNullParameter_whenProcessSomethingNotNull_thenIllegalArgumentException() {
+        NullParameterExample example = new NullParameterExample();
+        example.processSomethingNotNull(null);
+    }
+    
+    @Test(expected = NullPointerException.class)
+    public void givenNullParameter_whenProcessSomethingElseNotNull_thenNullPointerException() {
+        NullParameterExample example = new NullParameterExample();
+        example.processSomethingElseNotNull(null);
+    }
+}
@@ -6,4 +6,7 @@ This module contains articles about core Java input and output (IO)

 - [Java – Create a File](https://www.baeldung.com/java-how-to-create-a-file)
 - [Check If a Directory Is Empty in Java](https://www.baeldung.com/java-check-empty-directory)
+- [Check If a File or Directory Exists in Java](https://www.baeldung.com/java-file-directory-exists)
+- [Copy a Directory in Java](https://www.baeldung.com/java-copy-directory)
+- [Java Files Open Options](https://www.baeldung.com/java-file-options)
 - [[<-- Prev]](/core-java-modules/core-java-io-2)
@@ -0,0 +1,82 @@
+package com.baeldung.linenumber;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.IOUtils;
+import org.junit.Test;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.List;
+import java.util.Scanner;
+import java.util.stream.Stream;
+
+import static org.junit.Assert.assertEquals;
+
+public class LineAtGivenNumberUnitTest {
+
+    private static final String FILE_PATH = "src/test/resources/linesInput.txt";
+
+    @Test
+    public void givenFile_whenUsingBufferedReader_thenExtractedLineIsCorrect() throws IOException {
+        try (BufferedReader br = Files.newBufferedReader(Paths.get(FILE_PATH))) {
+            for (int i = 0; i < 3; i++) {
+                br.readLine();
+            }
+
+            String extractedLine = br.readLine();
+            assertEquals("Line 4", extractedLine);
+        }
+    }
+
+    @Test
+    public void givenFile_whenUsingScanner_thenExtractedLineIsCorrect() throws IOException {
+        try (Scanner scanner = new Scanner(new File(FILE_PATH))) {
+            for (int i = 0; i < 3; i++) {
+                scanner.nextLine();
+            }
+
+            String extractedLine = scanner.nextLine();
+            assertEquals("Line 4", extractedLine);
+        }
+    }
+
+    @Test
+    public void givenSmallFile_whenUsingFilesAPI_thenExtractedLineIsCorrect() throws IOException {
+        String extractedLine = Files.readAllLines(Paths.get(FILE_PATH)).get(4);
+
+        assertEquals("Line 5", extractedLine);
+    }
+
+    @Test
+    public void givenLargeFile_whenUsingFilesAPI_thenExtractedLineIsCorrect() throws IOException {
+        try (Stream<String> lines = Files.lines(Paths.get(FILE_PATH))) {
+            String extractedLine = lines.skip(4).findFirst().get();
+
+            assertEquals("Line 5", extractedLine);
+        }
+    }
+
+    @Test
+    public void givenFile_whenUsingFileUtils_thenExtractedLineIsCorrect() throws IOException {
+        ClassLoader classLoader = getClass().getClassLoader();
+        File file = new File(classLoader.getResource("linesInput.txt").getFile());
+
+        List<String> lines = FileUtils.readLines(file, "UTF-8");
+
+        String extractedLine = lines.get(0);
+        assertEquals("Line 1", extractedLine);
+    }
+
+    @Test
+    public void givenFile_whenUsingIOUtils_thenExtractedLineIsCorrect() throws IOException {
+        String fileContent = IOUtils.toString(new FileInputStream(FILE_PATH), StandardCharsets.UTF_8);
+
+        String extractedLine = fileContent.split(System.lineSeparator())[0];
+        assertEquals("Line 1", extractedLine);
+    }
+}
@@ -0,0 +1,5 @@
+Line 1
+Line 2
+Line 3
+Line 4
+Line 5
@@ -10,4 +10,5 @@ This module contains articles about working with the Java Virtual Machine (JVM).
 - [boolean and boolean[] Memory Layout in the JVM](https://www.baeldung.com/jvm-boolean-memory-layout)
 - [Where Is the Array Length Stored in JVM?](https://www.baeldung.com/java-jvm-array-length)
 - [Memory Address of Objects in Java](https://www.baeldung.com/java-object-memory-address)
+- [List All Classes Loaded in a Specific Class Loader](https://www.baeldung.com/java-list-classes-class-loader)
 - More articles: [[<-- prev]](/core-java-modules/core-java-jvm)
@@ -0,0 +1,19 @@
+package com.baeldung.loadedclasslisting;
+
+import java.util.Arrays;
+
+public class Launcher {
+
+    public static void main(String[] args) {
+        printClassesLoadedBy("BOOTSTRAP");
+        printClassesLoadedBy("SYSTEM");
+        printClassesLoadedBy("EXTENSION");
+    }
+
+    private static void printClassesLoadedBy(String classLoaderType) {
+        System.out.println(classLoaderType + " ClassLoader : ");
+        Class<?>[] classes = ListLoadedClassesAgent.listLoadedClasses(classLoaderType);
+        Arrays.asList(classes)
+            .forEach(clazz -> System.out.println(clazz.getCanonicalName()));
+    }
+}
@@ -0,0 +1,40 @@
+package com.baeldung.loadedclasslisting;
+
+import java.lang.instrument.Instrumentation;
+
+public class ListLoadedClassesAgent {
+
+    private static Instrumentation instrumentation;
+
+    public static void premain(String agentArgs, Instrumentation instrumentation) {
+        ListLoadedClassesAgent.instrumentation = instrumentation;
+    }
+
+    public static Class<?>[] listLoadedClasses(String classLoaderType) {
+        if (instrumentation == null) {
+            throw new IllegalStateException(
+              "ListLoadedClassesAgent is not initialized.");
+        }
+        return instrumentation.getInitiatedClasses(
+          getClassLoader(classLoaderType));
+    }
+
+    private static ClassLoader getClassLoader(String classLoaderType) {
+        ClassLoader classLoader = null;
+        switch (classLoaderType) {
+        case "SYSTEM":
+            classLoader = ClassLoader.getSystemClassLoader();
+            break;
+        case "EXTENSION":
+            classLoader = ClassLoader.getSystemClassLoader().getParent();
+            break;
+        // passing a null value to the Instrumentation : getInitiatedClasses method
+        // defaults to the bootstrap class loader
+        case "BOOTSTRAP":
+            break;
+        default:
+            break;
+        }
+        return classLoader;
+    }
+}
@@ -0,0 +1 @@
+Premain-Class: com.baeldung.loadedclasslisting.ListLoadedClassesAgent
--- a/Show More
+++ b/Show More
				`@@ -0,0 +1 @@`
				`Premain-Class: com.baeldung.loadedclasslisting.ListLoadedClassesAgent`