Merge remote-tracking branch 'eugenp/master'

.travis.yml

@@ -4,7 +4,7 @@ before_install:
   - echo "MAVEN_OPTS='-Xmx2048M -Xss128M -XX:+CMSClassUnloadingEnabled -XX:+UseG1GC -XX:-UseGCOverheadLimit'" > ~/.mavenrc
 
 install: skip
-script: travis_wait 60 mvn -q install -Pdefault-first,default-second
+script: travis_wait 60 mvn -q install -Pdefault-first,default-second -Dgib.enabled=true
 
 sudo: required
 

algorithms-miscellaneous-2/README.md

@@ -17,3 +17,4 @@
 - [Round Up to the Nearest Hundred](https://www.baeldung.com/java-round-up-nearest-hundred)
 - [Calculate Percentage in Java](https://www.baeldung.com/java-calculate-percentage)
 - [Converting Between Byte Arrays and Hexadecimal Strings in Java](https://www.baeldung.com/java-byte-arrays-hex-strings)
+- [Convert Latitude and Longitude to a 2D Point in Java](https://www.baeldung.com/java-convert-latitude-longitude)

cdi/pom.xml

@@ -5,7 +5,7 @@
     <groupId>com.baeldung</groupId>
     <artifactId>cdi</artifactId>
     <version>1.0-SNAPSHOT</version>
-
+    
     <parent>
         <groupId>com.baeldung</groupId>
         <artifactId>parent-spring-4</artifactId>
@@ -14,6 +14,16 @@
     </parent>
 
     <dependencies>
+        <dependency>
+            <groupId>javax.enterprise</groupId>
+            <artifactId>cdi-api</artifactId>
+            <version>${cdi-api.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.jboss.weld.se</groupId>
+            <artifactId>weld-se-core</artifactId>
+            <version>${weld-se-core.version}</version>
+        </dependency>  
         <dependency>
             <groupId>org.hamcrest</groupId>
             <artifactId>hamcrest-core</artifactId>
@@ -42,11 +52,6 @@
             <artifactId>aspectjweaver</artifactId>
             <version>${aspectjweaver.version}</version>
         </dependency>
-        <dependency>
-            <groupId>org.jboss.weld.se</groupId>
-            <artifactId>weld-se-core</artifactId>
-            <version>${weld-se-core.version}</version>
-        </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-test</artifactId>
@@ -54,13 +59,13 @@
             <scope>test</scope>
         </dependency>
     </dependencies>
-
     <properties>
-        <aspectjweaver.version>1.8.9</aspectjweaver.version>
-        <weld-se-core.version>2.4.1.Final</weld-se-core.version>
+        <cdi-api.version>2.0.SP1</cdi-api.version>
+        <weld-se-core.version>3.0.5.Final</weld-se-core.version>
+        <aspectjweaver.version>1.9.2</aspectjweaver.version>
         <hamcrest-core.version>1.3</hamcrest-core.version>
         <assertj-core.version>3.10.0</assertj-core.version>
         <junit.version>4.12</junit.version>
+        <spring.version>5.1.2.RELEASE</spring.version>
     </properties>
-
 </project>

cdi/src/main/java/com/baeldung/cdi2observers/application/BootstrappingApplication.java

@@ -0,0 +1,15 @@
+package com.baeldung.cdi.cdi2observers.application;
+
+import com.baeldung.cdi.cdi2observers.events.ExampleEvent;
+import javax.enterprise.inject.se.SeContainer;
+import javax.enterprise.inject.se.SeContainerInitializer;
+
+public class BootstrappingApplication {
+    
+    public static void main(String... args) {
+        SeContainerInitializer containerInitializer = SeContainerInitializer.newInstance();
+        try (SeContainer container = containerInitializer.initialize()) {
+            container.getBeanManager().fireEvent(new ExampleEvent("Welcome to Baeldung!"));
+        }
+    }
+}

cdi/src/main/java/com/baeldung/cdi2observers/events/ExampleEvent.java

@@ -0,0 +1,14 @@
+package com.baeldung.cdi.cdi2observers.events;
+
+public class ExampleEvent {
+    
+   private final String eventMessage;
+
+    public ExampleEvent(String eventMessage) {
+        this.eventMessage = eventMessage;
+    }
+    
+    public String getEventMessage() {
+        return eventMessage;
+    }
+}

cdi/src/main/java/com/baeldung/cdi2observers/events/ExampleEventSource.java

@@ -0,0 +1,14 @@
+package com.baeldung.cdi.cdi2observers.events;
+
+import javax.enterprise.event.Event;
+import javax.inject.Inject;
+
+public class ExampleEventSource {
+    
+    @Inject
+    Event<ExampleEvent> exampleEvent;
+    
+    public void fireEvent() {
+        exampleEvent.fireAsync(new ExampleEvent("Welcome to Baeldung!"));
+    }   
+}

cdi/src/main/java/com/baeldung/cdi2observers/observers/AnotherExampleEventObserver.java

@@ -0,0 +1,12 @@
+package com.baeldung.cdi.cdi2observers.observers;
+
+import com.baeldung.cdi.cdi2observers.events.ExampleEvent;
+import javax.annotation.Priority;
+import javax.enterprise.event.Observes;
+
+public class AnotherExampleEventObserver {
+    
+    public String onEvent(@Observes @Priority(2) ExampleEvent event) {
+        return event.getEventMessage();
+    }   
+}

cdi/src/main/java/com/baeldung/cdi2observers/observers/ExampleEventObserver.java

@@ -0,0 +1,13 @@
+package com.baeldung.cdi.cdi2observers.observers;
+
+import com.baeldung.cdi.cdi2observers.events.ExampleEvent;
+import com.baeldung.cdi.cdi2observers.services.TextService;
+import javax.annotation.Priority;
+import javax.enterprise.event.Observes;
+
+public class ExampleEventObserver {
+    
+    public String onEvent(@Observes @Priority(1) ExampleEvent event, TextService textService) {
+        return textService.parseText(event.getEventMessage());
+    } 
+}

cdi/src/main/java/com/baeldung/cdi2observers/services/TextService.java

@@ -0,0 +1,8 @@
+package com.baeldung.cdi.cdi2observers.services;
+
+public class TextService {
+
+    public String parseText(String text) {
+        return text.toUpperCase();
+    }
+}

cdi/src/test/java/com/baeldung/test/cdi2observers/tests/TextServiceUnitTest.java

@@ -0,0 +1,14 @@
+package com.baeldung.cdi.cdi2observers.tests;
+
+import com.baeldung.cdi.cdi2observers.services.TextService;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
+
+public class TextServiceUnitTest {
+
+    @Test
+    public void givenTextServiceInstance_whenCalledparseText_thenCorrect() {
+        TextService textService = new TextService();
+        assertThat(textService.parseText("Baeldung")).isEqualTo("BAELDUNG");
+    }
+}

core-java-10/README.md

@@ -4,3 +4,4 @@
 - [Java 10 LocalVariable Type-Inference](http://www.baeldung.com/java-10-local-variable-type-inference)
 - [Guide to Java 10](http://www.baeldung.com/java-10-overview)
 - [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)

core-java-8/README.md

@@ -33,3 +33,4 @@
 - [An Overview of Regular Expressions Performance in Java](https://www.baeldung.com/java-regex-performance)
 - [Java Primitives versus Objects](https://www.baeldung.com/java-primitives-vs-objects)
 - [How to Use if/else Logic in Java 8 Streams](https://www.baeldung.com/java-8-streams-if-else-logic)
+- [How to Replace Many if Statements in Java](https://www.baeldung.com/java-replace-if-statements)

core-java-arrays/src/main/java/com/baeldung/array/operations/ArrayOperations.java

@@ -4,11 +4,13 @@ import java.lang.reflect.Array;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
+import java.util.LinkedList;
 import java.util.Random;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.function.IntPredicate;
 import java.util.function.Predicate;
+import java.util.stream.Stream;
 
 import org.apache.commons.lang3.ArrayUtils;
 
@@ -194,4 +196,16 @@ public class ArrayOperations {
     public static <T> T getRandomFromObjectArray(T[] array) {
         return array[new Random().nextInt(array.length)];
     }
+
+    public static Integer[] intersectionSimple(final Integer[] a, final Integer[] b){
+        return Stream.of(a).filter(Arrays.asList(b)::contains).toArray(Integer[]::new);
+    }
+
+    public static Integer[] intersectionSet(final Integer[] a, final Integer[] b){
+        return Stream.of(a).filter(Arrays.asList(b)::contains).distinct().toArray(Integer[]::new);
+    }
+
+    public static Integer[] intersectionMultiSet(final Integer[] a, final Integer[] b){
+        return Stream.of(a).filter(new LinkedList<>(Arrays.asList(b))::remove).toArray(Integer[]::new);
+    }
 }

core-java-arrays/src/test/java/com/baeldung/array/operations/IntersectionUnitTest.java

@@ -0,0 +1,66 @@
+package com.baeldung.array.operations;
+
+import org.junit.jupiter.api.Test;
+
+import static com.baeldung.array.operations.ArrayOperations.intersectionMultiSet;
+import static com.baeldung.array.operations.ArrayOperations.intersectionSet;
+import static com.baeldung.array.operations.ArrayOperations.intersectionSimple;
+import static org.assertj.core.api.Assertions.assertThat;
+
+class IntersectionUnitTest {
+    private static final Integer[] a = { 1, 3, 2 };
+    private static final Integer[] b = { 4, 3, 2, 4, 2, 3, 4, 4, 3 };
+    private static final Integer[] c = { 1, 3, 2, 3, 3, 2 };
+
+    @Test
+    void whenIntersectionSimpleIsUsed_thenCommonEntriesAreInTheResult() {
+        assertThat(intersectionSimple(a, b)).isEqualTo(new Integer[] { 3, 2 });
+        assertThat(intersectionSimple(b, a)).isEqualTo(new Integer[] { 3, 2, 2, 3, 3 });
+    }
+
+    @Test
+    void whenIntersectionSimpleIsUsedWithAnArrayAndItself_thenTheResultIsTheIdentity() {
+        assertThat(intersectionSimple(b, b)).isEqualTo(b);
+        assertThat(intersectionSimple(a, a)).isEqualTo(a);
+    }
+
+    @Test
+    void whenIntersectionSetIsUsed_thenCommonEntriesAreInTheResult() {
+        assertThat(intersectionSet(b, a)).isEqualTo(new Integer[] { 3, 2 });
+    }
+
+    @Test
+    void whenIntersectionSetIsUsed_thenTheNumberOfEntriesDoesNotChangeWithTheParameterOrder() {
+        assertThat(intersectionSet(a, b)).isEqualTo(new Integer[] { 3, 2 });
+        assertThat(intersectionSet(b, a)).isEqualTo(new Integer[] { 3, 2 });
+    }
+
+    @Test
+    void whenIntersectionSetIsUsedWithAnArrayAndWithItself_andTheInputHasNoDuplicateEntries_ThenTheResultIsTheIdentity() {
+        assertThat(intersectionSet(a, a)).isEqualTo(a);
+    }
+
+    @Test
+    void whenIntersectionSetIsUsedWithAnArrayAndWithItself_andTheInputHasDuplicateEntries_ThenTheResultIsNotTheIdentity() {
+        assertThat(intersectionSet(b, b)).isNotEqualTo(b);
+    }
+
+    @Test
+    void whenMultiSetIsUsed_thenCommonEntriesAreInTheResult() {
+        assertThat(intersectionMultiSet(b, a)).isEqualTo(new Integer[] { 3, 2 });
+    }
+
+    @Test
+    void whenIntersectionMultiSetIsUsed_thenTheNumberOfEntriesDoesNotChangeWithTheParameterOrder() {
+        assertThat(intersectionMultiSet(a, b)).isEqualTo(new Integer[] { 3, 2 });
+        assertThat(intersectionMultiSet(b, a)).isEqualTo(new Integer[] { 3, 2 });
+        assertThat(intersectionMultiSet(b, c)).isEqualTo(new Integer[] { 3, 2, 2, 3, 3 });
+        assertThat(intersectionMultiSet(c, b)).isEqualTo(new Integer[] { 3, 2, 3, 3, 2 });
+    }
+
+    @Test
+    void whenIntersectionMultiSetIsUsedWithAnArrayAndWithItself_ThenTheResultIsTheIdentity() {
+        assertThat(intersectionMultiSet(b, b)).isEqualTo(b);
+        assertThat(intersectionMultiSet(a, a)).isEqualTo(a);
+    }
+}

core-java-collections/README.md

@@ -50,3 +50,4 @@
 - [Check If Two Lists are Equal in Java](http://www.baeldung.com/java-test-a-list-for-ordinality-and-equality)
 - [Java List Initialization in One Line](https://www.baeldung.com/java-init-list-one-line)
 - [ClassCastException: Arrays$ArrayList cannot be cast to ArrayList](https://www.baeldung.com/java-classcastexception-arrays-arraylist)
+- [A Guide to EnumMap](https://www.baeldung.com/java-enum-map)

core-java-io/README.md

@@ -34,3 +34,4 @@
 - [Read a File into an ArrayList](https://www.baeldung.com/java-file-to-arraylist)
 - [Guide to Java OutputStream](https://www.baeldung.com/java-outputstream)
 - [Reading a CSV File into an Array](https://www.baeldung.com/java-csv-file-array)
+- [Guide to BufferedReader](https://www.baeldung.com/java-buffered-reader)

core-java-lang/README.md

@@ -56,4 +56,5 @@
 - [How to Separate Double into Integer and Decimal Parts](https://www.baeldung.com/java-separate-double-into-integer-decimal-parts)
 - [“Sneaky Throws” in Java](http://www.baeldung.com/java-sneaky-throws)
 - [Inheritance and Composition (Is-a vs Has-a relationship) in Java](http://www.baeldung.com/java-inheritance-composition)
+- [A Guide to Constructors in Java](https://www.baeldung.com/java-constructors)
 

core-java/README.md

@@ -85,3 +85,6 @@
 - [A Guide to SimpleDateFormat](https://www.baeldung.com/java-simple-date-format)
 - [SSL Handshake Failures](https://www.baeldung.com/java-ssl-handshake-failures)
 - [Implementing a Binary Tree in Java](https://www.baeldung.com/java-binary-tree)
+- [Changing the Order in a Sum Operation Can Produce Different Results?](https://www.baeldung.com/java-floating-point-sum-order)
+- [Java – Try with Resources](https://www.baeldung.com/java-try-with-resources)
+- [Abstract Classes in Java](https://www.baeldung.com/java-abstract-class)

core-java/src/main/java/com/baeldung/className/RetrievingClassName.java

@@ -0,0 +1,9 @@
+package com.baeldung.className;
+
+public class RetrievingClassName {
+
+    public class InnerClass {
+
+    }
+
+}

core-java/src/test/java/com/baeldung/className/RetrievingClassNameUnitTest.java

@@ -0,0 +1,156 @@
+package com.baeldung.className;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+public class RetrievingClassNameUnitTest {
+
+    // Retrieving Simple Name
+    @Test
+    public void givenRetrievingClassName_whenGetSimpleName_thenRetrievingClassName() {
+        assertEquals("RetrievingClassName", RetrievingClassName.class.getSimpleName());
+    }
+
+    @Test
+    public void givenPrimitiveInt_whenGetSimpleName_thenInt() {
+        assertEquals("int", int.class.getSimpleName());
+    }
+
+    @Test
+    public void givenRetrievingClassNameArray_whenGetSimpleName_thenRetrievingClassNameWithBrackets() {
+        assertEquals("RetrievingClassName[]", RetrievingClassName[].class.getSimpleName());
+        assertEquals("RetrievingClassName[][]", RetrievingClassName[][].class.getSimpleName());
+    }
+
+    @Test
+    public void givenAnonymousClass_whenGetSimpleName_thenEmptyString() {
+        assertEquals("", new RetrievingClassName() {}.getClass().getSimpleName());
+    }
+
+    // Retrieving Other Names
+    // - Primitive Types
+    @Test
+    public void givenPrimitiveInt_whenGetName_thenInt() {
+        assertEquals("int", int.class.getName());
+    }
+
+    @Test
+    public void givenPrimitiveInt_whenGetTypeName_thenInt() {
+        assertEquals("int", int.class.getTypeName());
+    }
+
+    @Test
+    public void givenPrimitiveInt_whenGetCanonicalName_thenInt() {
+        assertEquals("int", int.class.getCanonicalName());
+    }
+
+    // - Object Types
+    @Test
+    public void givenRetrievingClassName_whenGetName_thenCanonicalName() {
+        assertEquals("com.baeldung.className.RetrievingClassName", RetrievingClassName.class.getName());
+    }
+
+    @Test
+    public void givenRetrievingClassName_whenGetTypeName_thenCanonicalName() {
+        assertEquals("com.baeldung.className.RetrievingClassName", RetrievingClassName.class.getTypeName());
+    }
+
+    @Test
+    public void givenRetrievingClassName_whenGetCanonicalName_thenCanonicalName() {
+        assertEquals("com.baeldung.className.RetrievingClassName", RetrievingClassName.class.getCanonicalName());
+    }
+
+    // - Inner Classes
+    @Test
+    public void givenRetrievingClassNameInnerClass_whenGetName_thenCanonicalNameWithDollarSeparator() {
+        assertEquals("com.baeldung.className.RetrievingClassName$InnerClass", RetrievingClassName.InnerClass.class.getName());
+    }
+
+    @Test
+    public void givenRetrievingClassNameInnerClass_whenGetTypeName_thenCanonicalNameWithDollarSeparator() {
+        assertEquals("com.baeldung.className.RetrievingClassName$InnerClass", RetrievingClassName.InnerClass.class.getTypeName());
+    }
+
+    @Test
+    public void givenRetrievingClassNameInnerClass_whenGetCanonicalName_thenCanonicalName() {
+        assertEquals("com.baeldung.className.RetrievingClassName.InnerClass", RetrievingClassName.InnerClass.class.getCanonicalName());
+    }
+
+    // - Anonymous Classes
+    @Test
+    public void givenAnonymousClass_whenGetName_thenCallingClassCanonicalNameWithDollarSeparatorAndCountNumber() {
+        // These are the second and third appearences of an anonymous class in RetrievingClassNameUnitTest, hence $2 and $3 expectations
+        assertEquals("com.baeldung.className.RetrievingClassNameUnitTest$2", new RetrievingClassName() {}.getClass().getName());
+        assertEquals("com.baeldung.className.RetrievingClassNameUnitTest$3", new RetrievingClassName() {}.getClass().getName());
+    }
+
+    @Test
+    public void givenAnonymousClass_whenGetTypeName_thenCallingClassCanonicalNameWithDollarSeparatorAndCountNumber() {
+        // These are the fourth and fifth appearences of an anonymous class in RetrievingClassNameUnitTest, hence $4 and $5 expectations
+        assertEquals("com.baeldung.className.RetrievingClassNameUnitTest$4", new RetrievingClassName() {}.getClass().getTypeName());
+        assertEquals("com.baeldung.className.RetrievingClassNameUnitTest$5", new RetrievingClassName() {}.getClass().getTypeName());
+    }
+
+    @Test
+    public void givenAnonymousClass_whenGetCanonicalName_thenNull() {
+        assertNull(new RetrievingClassName() {}.getClass().getCanonicalName());
+    }
+
+    // - Arrays
+    @Test
+    public void givenPrimitiveIntArray_whenGetName_thenOpeningBracketsAndPrimitiveIntLetter() {
+        assertEquals("[I", int[].class.getName());
+        assertEquals("[[I", int[][].class.getName());
+    }
+
+    @Test
+    public void givenRetrievingClassNameArray_whenGetName_thenOpeningBracketsLetterLAndRetrievingClassNameGetName() {
+        assertEquals("[Lcom.baeldung.className.RetrievingClassName;", RetrievingClassName[].class.getName());
+        assertEquals("[[Lcom.baeldung.className.RetrievingClassName;", RetrievingClassName[][].class.getName());
+    }
+
+    @Test
+    public void givenRetrievingClassNameInnerClassArray_whenGetName_thenOpeningBracketsLetterLAndRetrievingClassNameInnerClassGetName() {
+        assertEquals("[Lcom.baeldung.className.RetrievingClassName$InnerClass;", RetrievingClassName.InnerClass[].class.getName());
+        assertEquals("[[Lcom.baeldung.className.RetrievingClassName$InnerClass;", RetrievingClassName.InnerClass[][].class.getName());
+    }
+
+    @Test
+    public void givenPrimitiveIntArray_whenGetTypeName_thenPrimitiveIntGetTypeNameWithBrackets() {
+        assertEquals("int[]", int[].class.getTypeName());
+        assertEquals("int[][]", int[][].class.getTypeName());
+    }
+
+    @Test
+    public void givenRetrievingClassNameArray_whenGetTypeName_thenRetrievingClassNameGetTypeNameWithBrackets() {
+        assertEquals("com.baeldung.className.RetrievingClassName[]", RetrievingClassName[].class.getTypeName());
+        assertEquals("com.baeldung.className.RetrievingClassName[][]", RetrievingClassName[][].class.getTypeName());
+    }
+
+    @Test
+    public void givenRetrievingClassNameInnerClassArray_whenGetTypeName_thenRetrievingClassNameInnerClassGetTypeNameWithBrackets() {
+        assertEquals("com.baeldung.className.RetrievingClassName$InnerClass[]", RetrievingClassName.InnerClass[].class.getTypeName());
+        assertEquals("com.baeldung.className.RetrievingClassName$InnerClass[][]", RetrievingClassName.InnerClass[][].class.getTypeName());
+    }
+
+    @Test
+    public void givenPrimitiveIntArray_whenGetCanonicalName_thenPrimitiveIntGetCanonicalNameWithBrackets() {
+        assertEquals("int[]", int[].class.getCanonicalName());
+        assertEquals("int[][]", int[][].class.getCanonicalName());
+    }
+
+    @Test
+    public void givenRetrievingClassNameArray_whenGetCanonicalName_thenRetrievingClassNameGetCanonicalNameWithBrackets() {
+        assertEquals("com.baeldung.className.RetrievingClassName[]", RetrievingClassName[].class.getCanonicalName());
+        assertEquals("com.baeldung.className.RetrievingClassName[][]", RetrievingClassName[][].class.getCanonicalName());
+    }
+
+    @Test
+    public void givenRetrievingClassNameInnerClassArray_whenGetCanonicalName_thenRetrievingClassNameInnerClassGetCanonicalNameWithBrackets() {
+        assertEquals("com.baeldung.className.RetrievingClassName.InnerClass[]", RetrievingClassName.InnerClass[].class.getCanonicalName());
+        assertEquals("com.baeldung.className.RetrievingClassName.InnerClass[][]", RetrievingClassName.InnerClass[][].class.getCanonicalName());
+    }
+
+}

java-dates/README.md

@@ -24,3 +24,4 @@
 - [Add Hours To a Date In Java](http://www.baeldung.com/java-add-hours-date)
 - [Guide to DateTimeFormatter](https://www.baeldung.com/java-datetimeformatter)
 - [Format ZonedDateTime to String](https://www.baeldung.com/java-format-zoned-datetime-string)
+- [Convert Between java.time.Instant and java.sql.Timestamp](Convert Between java.time.Instant and java.sql.Timestamp)

java-strings/src/main/java/com/baeldung/string/checkinputs/CheckIntegerInput.java

@@ -0,0 +1,19 @@
+package com.baeldung.string.checkinputs;
+
+import java.util.Scanner;
+
+public class CheckIntegerInput {
+
+    public static void main(String[] args) {
+
+        try (Scanner scanner = new Scanner(System.in)) {
+            System.out.println("Enter an integer : ");
+            
+            if (scanner.hasNextInt()) {
+                System.out.println("You entered : " + scanner.nextInt());
+            } else {
+                System.out.println("The input is not an integer");
+            }
+        }
+    }
+}

java-strings/src/main/java/com/baeldung/stringduplicates/RemoveDuplicateFromString.java

@@ -44,16 +44,16 @@ public class RemoveDuplicateFromString {
     }
 
     String removeDuplicatesUsingSorting(String str) {
-
-        char[] chars = str.toCharArray();
-
-        Arrays.sort(chars);
-
         StringBuilder sb = new StringBuilder();
-        sb.append(chars[0]);
-        for (int i = 1; i < chars.length; i++) {
-            if (chars[i] != chars[i - 1]) {
-                sb.append(chars[i]);
+        if(!str.isEmpty()) {
+            char[] chars = str.toCharArray();
+            Arrays.sort(chars);
+
+            sb.append(chars[0]);
+            for (int i = 1; i < chars.length; i++) {
+                if (chars[i] != chars[i - 1]) {
+                    sb.append(chars[i]);
+                }
             }
         }
 
@@ -90,6 +90,13 @@ public class RemoveDuplicateFromString {
         return sb.toString();
     }
 
+
+    String removeDuplicatesUsingDistinct(String str) {
+        StringBuilder sb = new StringBuilder();
+        str.chars().distinct().forEach(c -> sb.append((char) c));
+        return sb.toString();
+    }
+
 }
 
 

java-strings/src/test/java/com/baeldung/string/StringReplaceAndRemoveUnitTest.java

@@ -0,0 +1,83 @@
+package com.baeldung.string;
+
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.Test;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class StringReplaceAndRemoveUnitTest {
+
+
+    @Test
+    public void givenTestStrings_whenReplace_thenProcessedString() {
+
+        String master = "Hello World Baeldung!";
+        String target = "Baeldung";
+        String replacement = "Java";
+        String processed = master.replace(target, replacement);
+        assertTrue(processed.contains(replacement));
+        assertFalse(processed.contains(target));
+
+    }
+
+    @Test
+    public void givenTestStrings_whenReplaceAll_thenProcessedString() {
+
+        String master2 = "Welcome to Baeldung, Hello World Baeldung";
+        String regexTarget= "(Baeldung)$";
+        String replacement = "Java";
+        String processed2 = master2.replaceAll(regexTarget, replacement);
+        assertTrue(processed2.endsWith("Java"));
+
+    }
+
+    @Test
+    public void givenTestStrings_whenStringBuilderMethods_thenProcessedString() {
+
+        String master = "Hello World Baeldung!";
+        String target = "Baeldung";
+        String replacement = "Java";
+
+        int startIndex = master.indexOf(target);
+        int stopIndex = startIndex + target.length();
+
+        StringBuilder builder = new StringBuilder(master);
+
+
+        builder.delete(startIndex, stopIndex);
+        assertFalse(builder.toString().contains(target));
+
+
+        builder.replace(startIndex, stopIndex, replacement);
+        assertTrue(builder.toString().contains(replacement));
+
+
+    }
+
+
+    @Test
+    public void givenTestStrings_whenStringUtilsMethods_thenProcessedStrings() {
+
+        String master = "Hello World Baeldung!";
+        String target = "Baeldung";
+        String replacement = "Java";
+
+        String processed = StringUtils.replace(master, target, replacement);
+        assertTrue(processed.contains(replacement));
+
+        String master2 = "Hello World Baeldung!";
+        String target2 = "baeldung";
+        String processed2 = StringUtils.replaceIgnoreCase(master2, target2, replacement);
+        assertFalse(processed2.contains(target));
+
+    }
+
+
+
+
+
+
+
+}

java-strings/src/test/java/com/baeldung/stringduplicates/RemoveDuplicateFromStringUnitTest.java

@@ -8,6 +8,8 @@ public class RemoveDuplicateFromStringUnitTest {
 
     private final static String STR1 = "racecar";
     private final static String STR2 = "J2ee programming";
+    private final static String STR_EMPTY = "";
+
     private RemoveDuplicateFromString removeDuplicateFromString;
 
     @Before
@@ -20,6 +22,8 @@ public class RemoveDuplicateFromStringUnitTest {
     public void whenUsingCharArray_DuplicatesShouldBeRemovedWithoutKeepingStringOrder() {
         String str1 = removeDuplicateFromString.removeDuplicatesUsingCharArray(STR1);
         String str2 = removeDuplicateFromString.removeDuplicatesUsingCharArray(STR2);
+        String strEmpty = removeDuplicateFromString.removeDuplicatesUsingCharArray(STR_EMPTY);
+        Assert.assertEquals("", strEmpty);
         Assert.assertEquals("ecar", str1);
         Assert.assertEquals("J2e poraming", str2);
     }
@@ -28,6 +32,9 @@ public class RemoveDuplicateFromStringUnitTest {
     public void whenUsingLinkedHashSet_DuplicatesShouldBeRemovedAndItKeepStringOrder() {
         String str1 = removeDuplicateFromString.removeDuplicatesUsinglinkedHashSet(STR1);
         String str2 = removeDuplicateFromString.removeDuplicatesUsinglinkedHashSet(STR2);
+
+        String strEmpty = removeDuplicateFromString.removeDuplicatesUsinglinkedHashSet(STR_EMPTY);
+        Assert.assertEquals("", strEmpty);
         Assert.assertEquals("race", str1);
         Assert.assertEquals("J2e progamin", str2);
     }
@@ -36,6 +43,9 @@ public class RemoveDuplicateFromStringUnitTest {
     public void whenUsingSorting_DuplicatesShouldBeRemovedWithoutKeepingStringOrder() {
         String str1 = removeDuplicateFromString.removeDuplicatesUsingSorting(STR1);
         String str2 = removeDuplicateFromString.removeDuplicatesUsingSorting(STR2);
+
+        String strEmpty = removeDuplicateFromString.removeDuplicatesUsingSorting(STR_EMPTY);
+        Assert.assertEquals("", strEmpty);
         Assert.assertEquals("acer", str1);
         Assert.assertEquals(" 2Jaegimnopr", str2);
     }
@@ -44,6 +54,8 @@ public class RemoveDuplicateFromStringUnitTest {
     public void whenUsingHashSet_DuplicatesShouldBeRemovedWithoutKeepingStringOrder() {
         String str1 = removeDuplicateFromString.removeDuplicatesUsingHashSet(STR1);
         String str2 = removeDuplicateFromString.removeDuplicatesUsingHashSet(STR2);
+        String strEmpty = removeDuplicateFromString.removeDuplicatesUsingHashSet(STR_EMPTY);
+        Assert.assertEquals("", strEmpty);
         Assert.assertEquals("arce", str1);
         Assert.assertEquals(" pa2regiJmno", str2);
     }
@@ -52,7 +64,19 @@ public class RemoveDuplicateFromStringUnitTest {
     public void whenUsingIndexOf_DuplicatesShouldBeRemovedWithoutKeepingStringOrder() {
         String str1 = removeDuplicateFromString.removeDuplicatesUsingIndexOf(STR1);
         String str2 = removeDuplicateFromString.removeDuplicatesUsingIndexOf(STR2);
+        String strEmpty = removeDuplicateFromString.removeDuplicatesUsingIndexOf(STR_EMPTY);
+        Assert.assertEquals("", strEmpty);
         Assert.assertEquals("ecar", str1);
         Assert.assertEquals("J2e poraming", str2);
     }
+
+    @Test
+    public void whenUsingJava8_DuplicatesShouldBeRemovedAndItKeepStringOrder() {
+        String str1 = removeDuplicateFromString.removeDuplicatesUsingDistinct(STR1);
+        String str2 = removeDuplicateFromString.removeDuplicatesUsingDistinct(STR2);
+        String strEmpty = removeDuplicateFromString.removeDuplicatesUsingDistinct(STR_EMPTY);
+        Assert.assertEquals("", strEmpty);
+        Assert.assertEquals("race", str1);
+        Assert.assertEquals("J2e progamin", str2);
+    }
 }

jee-7/src/main/java/com/baeldung/batch/understanding/ChunkExceptionSkipReadListener.java

@@ -0,0 +1,11 @@
+package com.baeldung.batch.understanding;
+
+import javax.batch.api.chunk.listener.SkipReadListener;
+import javax.inject.Named;
+
+@Named
+public class ChunkExceptionSkipReadListener implements SkipReadListener {
+    @Override
+    public void onSkipReadItem(Exception e) throws Exception {
+    }
+}