Merge branch 'master' into BAEL-2940_component_scan

.gitignore

@@ -1,4 +1,5 @@
 */bin/*
+bin/
 
 *.class
 
@@ -21,6 +22,9 @@
 *.iws
 out/
 
+# VSCode
+.vscode/
+
 # Mac
 .DS_Store
 

algorithms-miscellaneous-3/README.md

@@ -6,4 +6,4 @@
 - [Practical Java Examples of the Big O Notation](http://www.baeldung.com/java-algorithm-complexity)
 - [Checking If a List Is Sorted in Java](https://www.baeldung.com/java-check-if-list-sorted)
 - [Checking if a Java Graph has a Cycle](https://www.baeldung.com/java-graph-has-a-cycle)
-- [A Guide to the Folding Technique](https://www.baeldung.com/folding-hashing-technique)
+- [A Guide to the Folding Technique in Java](https://www.baeldung.com/folding-hashing-technique)

apache-olingo/olingo2/pom.xml

@@ -10,10 +10,10 @@
 	<description>Sample Olingo 2 Project</description>
 
     <parent>
-		<groupId>org.springframework.boot</groupId>
-		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.1.3.RELEASE</version>
-		<relativePath /> <!-- lookup parent from repository -->
+        <artifactId>parent-boot-2</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-2</relativePath>
     </parent>
 
 	<dependencies>
@@ -82,7 +82,6 @@
 	</build>
 
 	<properties>
-		<java.version>1.8</java.version>
 		<olingo2.version>2.0.11</olingo2.version>
 	</properties>
 

apache-olingo/olingo2/src/test/java/org/baeldung/examples/olingo2/Olingo2SampleApplicationUnitTest.java

@@ -7,7 +7,7 @@ import org.springframework.test.context.junit4.SpringRunner;
 
 @RunWith(SpringRunner.class)
 @SpringBootTest
-public class Olingo2SampleApplicationTests {
+public class Olingo2SampleApplicationUnitTest {
 
 	@Test
 	public void contextLoads() {

apache-pulsar/pom.xml

@@ -7,6 +7,13 @@
     <version>0.0.1</version>
     <name>apache-pulsar</name>
 
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>..</relativePath>
+    </parent>
+
     <dependencies>
         <dependency>
             <groupId>org.apache.pulsar</groupId>

apache-pulsar/src/main/java/com/baeldung/ConsumerUnitTest.java

@@ -7,7 +7,7 @@ import org.apache.pulsar.client.api.Message;
 import org.apache.pulsar.client.api.PulsarClient;
 import org.apache.pulsar.client.api.SubscriptionType;
 
-public class ConsumerTest {
+public class ConsumerUnitTest {
 
     private static final String SERVICE_URL = "pulsar://localhost:6650";
     private static final String TOPIC_NAME = "test-topic";

apache-pulsar/src/main/java/com/baeldung/ProducerUnitTest.java

@@ -11,7 +11,7 @@ import org.apache.pulsar.client.api.PulsarClientException;
 import java.io.IOException;
 import java.util.stream.IntStream;
 
-public class ProducerTest {
+public class ProducerUnitTest {
 
     private static final String SERVICE_URL = "pulsar://localhost:6650";
     private static final String TOPIC_NAME = "test-topic";

apache-pulsar/src/main/java/com/baeldung/subscriptions/ExclusiveSubscriptionUnitTest.java

@@ -10,7 +10,7 @@ import org.apache.pulsar.client.api.SubscriptionType;
 
 import java.util.stream.IntStream;
 
-public class ExclusiveSubscriptionTest {
+public class ExclusiveSubscriptionUnitTest {
     private static final String SERVICE_URL = "pulsar://localhost:6650";
     private static final String TOPIC_NAME = "test-topic";
     private static final String SUBSCRIPTION_NAME = "test-subscription";

apache-pulsar/src/main/java/com/baeldung/subscriptions/FailoverSubscriptionUnitTest.java

@@ -11,7 +11,7 @@ import org.apache.pulsar.client.api.SubscriptionType;
 
 import java.util.stream.IntStream;
 
-public class FailoverSubscriptionTest {
+public class FailoverSubscriptionUnitTest {
     private static final String SERVICE_URL = "pulsar://localhost:6650";
     private static final String TOPIC_NAME = "failover-subscription-test-topic";
     private static final String SUBSCRIPTION_NAME = "test-subscription";

aws/pom.xml

@@ -112,7 +112,6 @@
     </repositories>
 
     <properties>
-        <commons-io.version>2.5</commons-io.version>
         <aws-lambda-java-events.version>1.3.0</aws-lambda-java-events.version>
         <aws-lambda-java-core.version>1.1.0</aws-lambda-java-core.version>
         <gson.version>2.8.0</gson.version>

core-groovy-2/pom.xml

@@ -175,8 +175,6 @@
         <junit.platform.version>1.0.0</junit.platform.version>
         <hsqldb.version>2.4.0</hsqldb.version>
         <spock-core.version>1.1-groovy-2.4</spock-core.version>
-        <commons-lang3.version>3.9</commons-lang3.version>
-        <java.version>1.8</java.version>
         <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
         <logback.version>1.2.3</logback.version>
         <groovy.version>2.5.7</groovy.version>

core-groovy-2/src/main/groovy/com/baeldung/concatenate/Wonder.groovy

@@ -0,0 +1,52 @@
+package com.baeldung.concatenate
+
+class Wonder {
+
+    String numOfWonder = 'seven'
+
+    String operator_plus() {
+        return 'The ' + numOfWonder + ' wonders of the world'
+    }
+
+    String operator_left() {
+        return 'The ' << numOfWonder << ' wonders of ' << 'the world'
+    }
+
+    String interpolation_one() {
+        return "The $numOfWonder wonders of the world"
+
+    }
+
+    String interpolation_two() {
+        return "The ${numOfWonder} wonders of the world"
+    }
+
+    String multilineString() {
+        return """
+            There are $numOfWonder wonders of the world.
+            Can you name them all? 
+            1. The Great Pyramid of Giza
+            2. Hanging Gardens of Babylon
+            3. Colossus of Rhode
+            4. Lighthouse of Alexendra
+            5. Temple of Artemis
+            6. Status of Zeus at Olympia
+            7. Mausoleum at Halicarnassus
+        """
+    }
+
+    String method_concat() {
+        return 'The '.concat(numOfWonder).concat(' wonders of the world')
+
+    }
+
+    String method_builder() {
+        return new StringBuilder()
+                .append('The ').append(numOfWonder).append(' wonders of the world')
+    }
+
+    String method_buffer() {
+        return new StringBuffer()
+                .append('The ').append(numOfWonder).append(' wonders of the world')
+    }
+}

core-groovy-2/src/test/groovy/com/baeldung/concatenate/WonderUnitTest.groovy

@@ -0,0 +1,69 @@
+package com.baeldung.concatenate
+
+import org.junit.Before
+import org.junit.Test
+
+import static org.junit.Assert.*
+
+class WonderUnitTest {
+
+    static final String EXPECTED_SINGLE_LINE = "The seven wonders of the world"
+
+    Wonder wonder
+
+    @Before
+    void before() {
+        wonder = new Wonder()
+    }
+
+    @Test
+    void whenUsingOperatorPlus_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.operator_plus())
+    }
+
+    @Test
+    void whenUsingOperatorLeft_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.operator_left())
+    }
+
+    @Test
+    void whenUsingInterpolationOne_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.interpolation_one())
+    }
+
+    @Test
+    void whenUsingInterpolationTwo_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.interpolation_two())
+    }
+
+    @Test
+    void whenUsingMultiline_thenConcatCorrectly() {
+        def expectedMultiline = """
+            There are seven wonders of the world.
+            Can you name them all? 
+            1. The Great Pyramid of Giza
+            2. Hanging Gardens of Babylon
+            3. Colossus of Rhode
+            4. Lighthouse of Alexendra
+            5. Temple of Artemis
+            6. Status of Zeus at Olympia
+            7. Mausoleum at Halicarnassus
+        """
+        assertEquals(expectedMultiline, wonder.multilineString())
+    }
+
+    @Test
+    void whenUsingMethodConcat_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.method_concat())
+    }
+
+    @Test
+    void whenUsingMethodBuilder_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.method_builder())
+    }
+
+    @Test
+    void whenUsingMethodBuffer_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.method_buffer())
+    }
+}

core-java-modules/core-java-11/src/main/java/com/baeldung/predicate/not/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Negate a Predicate Method Reference with Java 11](https://www.baeldung.com/java-negate-predicate-method-reference)

core-java-modules/core-java-12/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [String API Updates in Java 12](https://www.baeldung.com/java12-string-api)

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

@@ -175,7 +175,6 @@
 
     <properties>
         <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>

core-java-modules/core-java-arrays/src/main/java/com/baeldung/array/SortedArrayChecker.java

@@ -0,0 +1,71 @@
+package com.baeldung.array;
+
+import com.baeldung.arraycopy.model.Employee;
+
+public class SortedArrayChecker {
+    boolean isSorted(int[] array, int length) {
+        if (array == null || length < 2)
+            return true;
+
+        if (array[length - 2] > array[length - 1])
+            return false;
+
+        return isSorted(array, length - 1);
+    }
+
+    boolean isSorted(int[] array) {
+        for (int i = 0; i < array.length - 1; i++) {
+            if (array[i] > array[i + 1])
+                return false;
+        }
+
+        return true;
+    }
+
+    boolean isSorted(String[] array, int length) {
+        if (array == null || length < 2)
+            return true;
+
+        if (array[length - 2].compareTo(array[length - 1]) > 0)
+            return false;
+
+        return isSorted(array, length - 1);
+    }
+
+boolean isSorted(String[] array) {
+    for (int i = 0; i < array.length - 1; ++i) {
+        if (array[i].compareTo(array[i + 1]) > 0)
+            return false;
+    }
+
+    return true;
+}
+
+    boolean isSortedByName(Employee[] array) {
+        for (int i = 0; i < array.length - 1; ++i) {
+            if (array[i].getName().compareTo(array[i + 1].getName()) > 0)
+                return false;
+        }
+
+        return true;
+    }
+
+boolean isSortedByAge(Employee[] array) {
+    for (int i = 0; i < array.length - 1; ++i) {
+        if (array[i].getAge() > (array[i + 1].getAge()))
+            return false;
+    }
+
+    return true;
+}
+
+    boolean isSortedByAge(Employee[] array, int length) {
+        if (array == null || length < 2)
+            return true;
+
+        if (array[length - 2].getAge() > array[length - 1].getAge())
+            return false;
+
+        return isSortedByAge(array, length - 1);
+    }
+}

core-java-modules/core-java-arrays/src/main/java/com/baeldung/arraycopy/model/Employee.java

@@ -6,6 +6,7 @@ public class Employee implements Serializable {
     private static final long serialVersionUID = -2454619097207585825L;
     private int id;
     private String name;
+    private int age;
 
     public Employee() {
     }
@@ -15,10 +16,24 @@ public class Employee implements Serializable {
         this.name = name;
     }
 
+    public Employee(int id, String name, int age) {
+        this.id = id;
+        this.name = name;
+        this.age = age;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
     public int getId() {
         return id;
     }
 
+    public void setAge(int age) {
+        this.age = age;
+    }
+
     public void setId(int id) {
         this.id = id;
     }

core-java-modules/core-java-arrays/src/test/java/com/baeldung/array/SortedArrayCheckerUnitTest.java

@@ -0,0 +1,73 @@
+package com.baeldung.array;
+
+import com.baeldung.arraycopy.model.Employee;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class SortedArrayCheckerUnitTest {
+
+    private static final int[] INTEGER_SORTED = {1, 3, 5, 7, 9};
+    private static final int[] INTEGER_NOT_SORTED = {1, 3, 11, 7};
+
+    private static final String[] STRING_SORTED = {"abc", "cde", "fgh"};
+    private static final String[] STRING_NOT_SORTED = {"abc", "fgh", "cde", "ijk"};
+
+    private final Employee[] EMPLOYEES_SORTED_BY_NAME = {
+            new Employee(1, "Carlos", 26),
+            new Employee(2, "Daniel", 31),
+            new Employee(3, "Marta", 27)};
+
+    private final Employee[] EMPLOYEES_NOT_SORTED_BY_NAME = {
+            new Employee(1, "Daniel", 31),
+            new Employee(2, "Carlos", 26),
+            new Employee(3, "Marta", 27)};
+
+    private final Employee[] EMPLOYEES_SORTED_BY_AGE = {
+            new Employee(1, "Carlos", 26),
+            new Employee(2, "Marta", 27),
+            new Employee(3, "Daniel", 31)};
+
+    private final Employee[] EMPLOYEES_NOT_SORTED_BY_AGE = {
+            new Employee(1, "Marta", 27),
+            new Employee(2, "Carlos", 26),
+            new Employee(3, "Daniel", 31)};
+
+    private SortedArrayChecker sortedArrayChecker;
+
+    @Before
+    public void setup() {
+        sortedArrayChecker = new SortedArrayChecker();
+    }
+
+    @Test
+    public void givenIntegerArray_thenReturnIfItIsSortedOrNot() {
+        assertThat(sortedArrayChecker.isSorted(INTEGER_SORTED)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(INTEGER_NOT_SORTED)).isEqualTo(false);
+
+        assertThat(sortedArrayChecker.isSorted(INTEGER_SORTED, INTEGER_SORTED.length)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(INTEGER_NOT_SORTED, INTEGER_NOT_SORTED.length)).isEqualTo(false);
+    }
+
+    @Test
+    public void givenStringArray_thenReturnIfItIsSortedOrNot() {
+        assertThat(sortedArrayChecker.isSorted(STRING_SORTED)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(STRING_NOT_SORTED)).isEqualTo(false);
+
+        assertThat(sortedArrayChecker.isSorted(STRING_SORTED, STRING_SORTED.length)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(STRING_NOT_SORTED, STRING_NOT_SORTED.length)).isEqualTo(false);
+    }
+
+    @Test
+    public void givenEmployeeArray_thenReturnIfItIsSortedOrNot() {
+        assertThat(sortedArrayChecker.isSortedByName(EMPLOYEES_SORTED_BY_NAME)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSortedByName(EMPLOYEES_NOT_SORTED_BY_NAME)).isEqualTo(false);
+
+        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_SORTED_BY_AGE)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_NOT_SORTED_BY_AGE)).isEqualTo(false);
+
+        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_SORTED_BY_AGE, EMPLOYEES_SORTED_BY_AGE.length)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_NOT_SORTED_BY_AGE, EMPLOYEES_NOT_SORTED_BY_AGE.length)).isEqualTo(false);
+    }
+}

core-java-modules/core-java-concurrency-advanced/pom.xml

@@ -72,7 +72,6 @@
     <properties>
         <!-- util -->
         <guava.version>21.0</guava.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>

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

@@ -17,3 +17,4 @@
 - [Runnable vs. Callable in Java](http://www.baeldung.com/java-runnable-callable)
 - [What is Thread-Safety and How to Achieve it?](https://www.baeldung.com/java-thread-safety)
 - [How to Start a Thread in Java](https://www.baeldung.com/java-start-thread)
+- [How to Delay Code Execution in Java](https://www.baeldung.com/java-delay-code-execution)

core-java-modules/core-java-concurrency-basic/pom.xml

@@ -45,8 +45,6 @@
     </build>
 
     <properties>
-        <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
         <avaitility.version>1.7.0</avaitility.version>

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

@@ -62,7 +62,6 @@
     <properties>
         <!-- util -->
         <guava.version>21.0</guava.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>

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

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Will an Error Be Caught by Catch Block in Java?](https://www.baeldung.com/java-error-catch)

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

@@ -248,7 +248,6 @@
     <properties>
 
         <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <bouncycastle.version>1.55</bouncycastle.version>
         <commons-codec.version>1.10</commons-codec.version>
         <commons-math3.version>3.6.1</commons-math3.version>

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

@@ -35,7 +35,6 @@
     </dependencies>
 
     <properties>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <assertj.version>3.6.1</assertj.version>
     </properties>
 </project>

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

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Why Do Local Variables Used in Lambdas Have to Be Final or Effectively Final?](https://www.baeldung.com/java-lambda-effectively-final-local-variables)

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

@@ -75,13 +75,7 @@
     </build>
 
     <properties>
-        
-        <!-- marshalling -->
-        <jackson.version>2.8.5</jackson.version>
         <gson.version>2.8.2</gson.version>
-
-        <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <!-- testing -->
         <assertj-core.version>3.10.0</assertj-core.version>
         <equalsverifier.version>3.0.3</equalsverifier.version>

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

@@ -76,9 +76,6 @@
     <properties>
         <gson.version>2.8.2</gson.version>
         
-        <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
-        
         <javax.mail.version>1.5.0-b01</javax.mail.version>
         
         <!-- testing -->

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

@@ -42,8 +42,6 @@
 
     <properties>
         <javax.mail.version>1.5.0-b01</javax.mail.version>
-        <commons-io.version>2.5</commons-io.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <springframework.spring-web.version>4.3.4.RELEASE</springframework.spring-web.version>
     </properties>	
 </project>

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

@@ -19,12 +19,12 @@
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
-            <version>${h2database.version}</version>
+            <version>${h2.version}</version>
         </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
-            <version>${jackson.databind.version}</version>
+            <version>${jackson.version}</version>
         </dependency>
     </dependencies>
 
@@ -48,7 +48,5 @@
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
         <hibernate.core.version>5.4.0.Final</hibernate.core.version>
-        <h2database.version>1.4.197</h2database.version>
-        <jackson.databind.version>2.9.8</jackson.databind.version>
     </properties>
 </project>

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

@@ -68,7 +68,6 @@
 
     <properties>
         <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>
     

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

@@ -23,11 +23,4 @@
        
     </dependencies>
 
-    <properties>
-
-        <!-- util -->
-        <commons-lang3.version>3.8.1</commons-lang3.version>
-      
-    </properties>
-
 </project>

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

@@ -43,7 +43,6 @@
     <properties>
 
         <!-- util -->
-        <commons-lang3.version>3.8.1</commons-lang3.version>
         <bouncycastle.version>1.60</bouncycastle.version>
         <commons-codec.version>1.11</commons-codec.version>
 

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

@@ -264,7 +264,6 @@
 
         <!-- util -->
         <guava.version>23.0</guava.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <bouncycastle.version>1.55</bouncycastle.version>
         <commons-codec.version>1.10</commons-codec.version>
         <commons-math3.version>3.6.1</commons-math3.version>

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

@@ -113,7 +113,7 @@
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
-            <version>${h2database.version}</version>
+            <version>${h2.version}</version>
         </dependency>
         <!-- instrumentation -->
         <dependency>
@@ -453,8 +453,6 @@
         <gson.version>2.8.2</gson.version>
 
         <!-- util -->
-        <commons-lang3.version>3.9</commons-lang3.version>
-        <commons-io.version>2.5</commons-io.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <decimal4j.version>1.0.3</decimal4j.version>
         <unix4j.version>0.4</unix4j.version>
@@ -471,7 +469,6 @@
         <maven-surefire-plugin.version>2.21.0</maven-surefire-plugin.version>
         
         <javamoney.moneta.version>1.1</javamoney.moneta.version>
-        <h2database.version>1.4.197</h2database.version>
         <esapi.version>2.1.0.1</esapi.version>
         <jmh-core.version>1.19</jmh-core.version>
        

core-java-modules/multimodulemavenproject/daomodule/pom.xml

@@ -1,15 +1,16 @@
 <?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.daomodule</groupId>
+    <artifactId>daomodule</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+    
     <parent>
         <groupId>com.baeldung.multimodulemavenproject</groupId>
         <artifactId>multimodulemavenproject</artifactId>
         <version>1.0</version>
     </parent>
-    <groupId>com.baeldung.daomodule</groupId>
-    <artifactId>daomodule</artifactId>
-    <version>1.0</version>
-    <packaging>jar</packaging>
     
     <build>
         <plugins>

core-kotlin-io/pom.xml

@@ -22,7 +22,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>${junit.jupiter.version}</version>
+            <version>${junit-jupiter.version}</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -88,7 +88,7 @@
 
     <properties>
         <kotlin.version>1.3.30</kotlin.version>
-        <junit.jupiter.version>5.4.2</junit.jupiter.version>
+        <junit-jupiter.version>5.4.2</junit-jupiter.version>
         <mockito.version>2.27.0</mockito.version>
         <byte-buddy.version>1.9.12</byte-buddy.version>
         <assertj.version>3.10.0</assertj.version>

core-kotlin/pom.xml

@@ -39,7 +39,7 @@
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
-            <version>${h2database.version}</version>
+            <version>${h2.version}</version>
         </dependency>
         <dependency>
             <groupId>com.github.kittinunf.fuel</groupId>
@@ -76,11 +76,9 @@
 
     <properties>
         <commons-math3.version>3.6.1</commons-math3.version>
-        <commons-lang3.version>3.8.1</commons-lang3.version>
         <junit.platform.version>1.1.1</junit.platform.version>
         <junit.vintage.version>5.2.0</junit.vintage.version>
         <assertj.version>3.10.0</assertj.version>
-        <h2database.version>1.4.197</h2database.version>
         <fuel.version>1.15.0</fuel.version>
 		<kovenant.version>3.3.0</kovenant.version>
 		<injekt-core.version>1.16.1</injekt-core.version>

couchbase/pom.xml

@@ -69,7 +69,6 @@
     <properties>
         <couchbase.client.version>2.5.0</couchbase.client.version>
         <spring-framework.version>4.3.5.RELEASE</spring-framework.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
     </properties>
 
 </project>

custom-pmd/pom.xml

@@ -8,6 +8,12 @@
     <packaging>jar</packaging>
     <url>http://maven.apache.org</url>
     
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
     <dependencies>
         <dependency>
             <groupId>net.sourceforge.pmd</groupId>

disruptor/pom.xml

@@ -115,7 +115,6 @@
 
     <properties>
         <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <disruptor.version>3.3.6</disruptor.version>
         <!-- testing -->
         <testng.version>6.10</testng.version>

dozer/pom.xml

@@ -26,7 +26,6 @@
     </dependencies>
 
     <properties>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <dozer.version>5.5.1</dozer.version>
     </properties>
 

flyway-cdi-extension/pom.xml

@@ -8,6 +8,13 @@
     <version>1.0-SNAPSHOT</version>
     <name>flyway-cdi-extension</name>
 
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>..</relativePath>
+    </parent>
+
     <dependencies>
         <dependency>
             <groupId>javax.enterprise</groupId>
@@ -51,6 +58,5 @@
 		<flyway-core.version>5.1.4</flyway-core.version>
 		<tomcat-jdbc.version>8.5.33</tomcat-jdbc.version>
 		<javax.annotation-api.version>1.3.2</javax.annotation-api.version>
-		<h2.version>1.4.197</h2.version>
     </properties>
 </project>

gson/pom.xml

@@ -64,7 +64,6 @@
         <!-- marshalling -->
         <gson.version>2.8.0</gson.version>
         <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <joda-time.version>2.9.6</joda-time.version>
     </properties>

guava-collections/pom.xml

@@ -55,7 +55,6 @@
     <properties>
         <!-- util -->
         <guava.version>24.0-jre</guava.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
 
         <!-- testing -->

guava/pom.xml

@@ -49,7 +49,6 @@
     <properties>
         <!-- util -->
         <guava.version>24.0-jre</guava.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
 
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>

httpclient-simple/pom.xml

@@ -297,7 +297,6 @@
     <properties>
         <!-- util -->
         <guava.version>19.0</guava.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-codec.version>1.10</commons-codec.version>
         <httpasyncclient.version>4.1.4</httpasyncclient.version>
         <!-- testing -->
@@ -305,7 +304,6 @@
         <httpcore.version>4.4.11</httpcore.version>
         <httpclient.version>4.5.8</httpclient.version> <!-- 4.3.6 --> <!-- 4.4-beta1 -->
         <!-- maven plugins -->
-        <maven-war-plugin.version>2.6</maven-war-plugin.version>
         <cargo-maven2-plugin.version>1.6.1</cargo-maven2-plugin.version>
     </properties>
 

httpclient/pom.xml

@@ -120,7 +120,6 @@
     <properties>
         <!-- util -->
         <guava.version>19.0</guava.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-codec.version>1.10</commons-codec.version>
         <httpasyncclient.version>4.1.4</httpasyncclient.version>
         <!-- testing -->

hystrix/pom.xml

@@ -65,7 +65,6 @@
         <hystrix-core.version>1.5.8</hystrix-core.version>
         <rxjava-core.version>0.20.7</rxjava-core.version>
         <!-- maven plugins -->
-        <maven-war-plugin.version>2.6</maven-war-plugin.version>
         <maven-resources-plugin.version>2.7</maven-resources-plugin.version>
         <hystrix-metrics-event-stream.version>1.5.8</hystrix-metrics-event-stream.version>
         <hystrix-dashboard.version>1.5.8</hystrix-dashboard.version>

jackson-2/src/test/java/com/baeldung/jackson/json/compare/JsonCompareUnitTest.java

@@ -0,0 +1,126 @@
+package com.baeldung.jackson.json.compare;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.Comparator;
+
+import org.junit.Test;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.NumericNode;
+import com.fasterxml.jackson.databind.node.TextNode;
+
+public class JsonCompareUnitTest {
+
+    @Test
+    public void givenTwoSameJsonDataObjects_whenCompared_thenAreEqual() throws IOException {
+        ObjectMapper mapper = new ObjectMapper();
+
+        String s1 = "{\"employee\": {\"id\": \"1212\",\"fullName\": \"John Miles\", \"age\": 34 }}";
+        String s2 = "{\"employee\": {\"id\": \"1212\",\"age\": 34, \"fullName\": \"John Miles\" }}";
+
+        JsonNode actualObj1 = mapper.readTree(s1);
+        JsonNode actualObj2 = mapper.readTree(s2);
+
+        assertEquals(actualObj1, actualObj2);
+
+    }
+
+    @Test
+    public void givenTwoSameNestedJsonDataObjects_whenCompared_thenEqual() throws IOException {
+        ObjectMapper mapper = new ObjectMapper();
+
+        String s1 = "{\"employee\": {\"id\": \"1212\",\"fullName\": \"John Miles\",\"age\": 34, \"contact\":{\"email\": \"john@xyz.com\",\"phone\": \"9999999999\"} }}";
+        String s2 = "{\"employee\": {\"id\": \"1212\",\"fullName\": \"John Miles\",\"age\": 34, \"contact\":{\"email\": \"john@xyz.com\",\"phone\": \"9999999999\"} }}";
+
+        JsonNode actualObj1 = mapper.readTree(s1);
+        JsonNode actualObj2 = mapper.readTree(s2);
+
+        assertEquals(actualObj1, actualObj2);
+
+    }
+
+    @Test
+    public void givenTwoSameListJsonDataObjects_whenCompared_thenEqual() throws IOException {
+        ObjectMapper mapper = new ObjectMapper();
+
+        String s1 = "{\"employee\": {\"id\": \"1212\",\"fullName\": \"John Miles\",\"age\": 34, \"skills\":[\"Java\", \"C++\", \"Python\"] }}";
+        String s2 = "{\"employee\": {\"id\": \"1212\",\"fullName\": \"John Miles\",\"age\": 34, \"skills\":[\"Java\", \"C++\", \"Python\"] }}";
+
+        JsonNode actualObj1 = mapper.readTree(s1);
+        JsonNode actualObj2 = mapper.readTree(s2);
+
+        assertEquals(actualObj1, actualObj2);
+
+    }
+
+    @Test
+    public void givenTwoJsonDataObjects_whenComparedUsingCustomNumericNodeComparator_thenEqual() throws IOException {
+        ObjectMapper mapper = new ObjectMapper();
+
+        String s1 = "{\"name\": \"John\",\"score\":5.0}";
+        String s2 = "{\"name\": \"John\",\"score\":5}";
+        JsonNode actualObj1 = mapper.readTree(s1);
+        JsonNode actualObj2 = mapper.readTree(s2);
+
+        NumericNodeComparator cmp = new NumericNodeComparator();
+
+        assertNotEquals(actualObj1, actualObj2);
+        assertTrue(actualObj1.equals(cmp, actualObj2));
+
+    }
+    
+    public class NumericNodeComparator implements Comparator<JsonNode> {
+        @Override
+        public int compare(JsonNode o1, JsonNode o2) {
+            if (o1.equals(o2)) {
+                return 0;
+            }
+            if ((o1 instanceof NumericNode) && (o2 instanceof NumericNode)) {
+                Double d1 = ((NumericNode) o1).asDouble();
+                Double d2 = ((NumericNode) o2).asDouble();
+                if (d1.compareTo(d2) == 0) {
+                    return 0;
+                }
+            }
+            return 1;
+        }
+    }
+    
+    @Test
+    public void givenTwoJsonDataObjects_whenComparedUsingCustomTextNodeComparator_thenEqual() throws IOException {
+        ObjectMapper mapper = new ObjectMapper();
+
+        String s1 = "{\"name\": \"JOHN\",\"score\":5}";
+        String s2 = "{\"name\": \"John\",\"score\":5}";
+        JsonNode actualObj1 = mapper.readTree(s1);
+        JsonNode actualObj2 = mapper.readTree(s2);
+
+        TextNodeComparator cmp = new TextNodeComparator();
+
+        assertNotEquals(actualObj1, actualObj2);
+        assertTrue(actualObj1.equals(cmp, actualObj2));
+
+    }
+    
+    public class TextNodeComparator implements Comparator<JsonNode> {
+        @Override
+        public int compare(JsonNode o1, JsonNode o2) {
+            if (o1.equals(o2)) {
+                return 0;
+            }
+            if ((o1 instanceof TextNode) && (o2 instanceof TextNode)) {
+                String s1 = ((TextNode) o1).asText();
+                String s2 = ((TextNode) o2).asText();
+                if (s1.equalsIgnoreCase(s2)) {
+                    return 0;
+                }
+            }
+            return 1;
+        }
+    }
+}

jackson-simple/pom.xml

@@ -118,7 +118,6 @@
 
     <properties>
         <!-- util -->
-        <commons-lang3.version>3.8</commons-lang3.version>
         <joda-time.version>2.10</joda-time.version>
         <gson.version>2.8.5</gson.version>
         <commons-collections4.version>4.2</commons-collections4.version>

jackson/pom.xml

@@ -118,7 +118,6 @@
 
     <properties>
         <!-- util -->
-        <commons-lang3.version>3.8</commons-lang3.version>
         <joda-time.version>2.10</joda-time.version>
         <gson.version>2.8.5</gson.version>
         <commons-collections4.version>4.2</commons-collections4.version>

java-collections-conversions/pom.xml

@@ -33,7 +33,6 @@
     </dependencies>
 
     <properties>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <assertj.version>3.6.1</assertj.version>
     </properties>

java-collections-maps-2/pom.xml

@@ -54,7 +54,6 @@
         <trove4j.version>3.0.2</trove4j.version>
         <fastutil.version>8.1.0</fastutil.version>
         <colt.version>1.2.0</colt.version>
-        <commons-lang3.version>3.8.1</commons-lang3.version>
         <assertj.version>3.11.1</assertj.version>
     </properties>
 

java-collections-maps/pom.xml

@@ -44,7 +44,6 @@
     </dependencies>
 
     <properties>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>
         <avaitility.version>1.7.0</avaitility.version>

java-dates/pom.xml

@@ -74,8 +74,6 @@
     </build>
 
     <properties>
-        <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <joda-time.version>2.10</joda-time.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>

java-ee-8-security-api/pom.xml

@@ -72,8 +72,6 @@
         <javaee-version>8.0</javaee-version>
         <liberty-maven-plugin.version>2.3</liberty-maven-plugin.version>
         <openliberty-runtime.version>18.0.0.1</openliberty-runtime.version>
-        
-        <maven-war-plugin.version>3.2.2</maven-war-plugin.version>
     </properties>
 
 </project>

java-numbers-2/.gitignore

@@ -0,0 +1,26 @@
+*.class
+
+0.*
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+.resourceCache
+
+# Packaged files #
+*.jar
+*.war
+*.ear
+
+# Files generated by integration tests
+*.txt
+backup-pom.xml
+/bin/
+/temp
+
+#IntelliJ specific
+.idea/
+*.iml

java-numbers-2/pom.xml

@@ -0,0 +1,135 @@
+<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>
+    <artifactId>java-numbers-2</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>java-numbers-2</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>log4j</groupId>
+            <artifactId>log4j</artifactId>
+            <version>${log4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>${org.slf4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>${logback.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${jmh-core.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${jmh-generator.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.decimal4j</groupId>
+            <artifactId>decimal4j</artifactId>
+            <version>${decimal4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>java-numbers-2</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+
+        <plugins>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-javadoc-plugin</artifactId>
+                <version>${maven-javadoc-plugin.version}</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <profiles>
+        <profile>
+            <id>integration</id>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-surefire-plugin</artifactId>
+                        <executions>
+                            <execution>
+                                <phase>integration-test</phase>
+                                <goals>
+                                    <goal>test</goal>
+                                </goals>
+                                <configuration>
+                                    <includes>
+                                        <include>**/*IntegrationTest.java</include>
+                                    </includes>
+                                </configuration>
+                            </execution>
+                        </executions>
+                        <configuration>
+                            <systemPropertyVariables>
+                                <test.mime>json</test.mime>
+                            </systemPropertyVariables>
+                        </configuration>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
+
+    <properties>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <decimal4j.version>1.0.3</decimal4j.version>
+        <commons-lang3.version>3.5</commons-lang3.version>
+
+        <assertj.version>3.6.1</assertj.version>
+
+        <org.slf4j.version>1.7.21</org.slf4j.version>
+        <logback.version>1.1.7</logback.version>
+
+        <maven-surefire-plugin.version>2.21.0</maven-surefire-plugin.version>
+        <maven-javadoc-plugin.version>3.0.0-M1</maven-javadoc-plugin.version>
+        <maven-jar-plugin.version>3.0.2</maven-jar-plugin.version>
+    </properties>
+</project>

java-numbers-2/src/test/java/com/baeldung/lossyconversion/ConversionTechniquesUnitTest.java

@@ -0,0 +1,68 @@
+package com.baeldung.lossyconversion;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class ConversionTechniquesUnitTest {
+
+    @Test
+    public void testPrimitiveConversion() {
+        
+        long longNum = 24;
+        short shortNum = (short) longNum;
+        assertEquals(24, shortNum);
+
+        double doubleNum = 15.6;
+        int integerNum = (int) doubleNum;
+        assertEquals(15, integerNum);
+        
+        long largeLongNum = 32768;
+        short minShortNum = (short) largeLongNum;
+        assertEquals(-32768, minShortNum);
+        
+        long smallLongNum = -32769;
+        short maxShortNum = (short) smallLongNum;
+        assertEquals(32767, maxShortNum);
+        
+        long maxLong = Long.MAX_VALUE;
+        int minInt = (int) maxLong;
+        assertEquals(-1, minInt);
+        
+        long minLong = Long.MIN_VALUE;
+        int maxInt = (int) minLong;
+        assertEquals(0, maxInt);
+    }
+
+    @Test
+    public void testWrapperToPrimitiveConversion() {
+
+        Float floatNum = 17.564f;
+        long longNum = floatNum.longValue();
+        assertEquals(17, longNum);
+
+        Double doubleNum = 15.9999;
+        longNum = doubleNum.longValue();
+        assertEquals(15, longNum);
+    }
+
+    @Test
+    public void testWrapperToPrimitiveConversionUsingMathRound() {
+
+        Double doubleNum = 15.9999;
+        long longNum = Math.round(doubleNum);
+        assertEquals(16, longNum);
+    }
+    
+    @Test
+    public void testWrapperConversion() {
+
+        Double doubleNum = 10.3;
+        double dbl = doubleNum.doubleValue(); //unboxing
+        int intgr = (int) dbl; //downcasting
+        Integer intNum = Integer.valueOf(intgr);
+        assertEquals(Integer.valueOf(10), intNum);
+    }
+    
+}

java-numbers/pom.xml

@@ -121,7 +121,6 @@
     <properties>
         <commons-math3.version>3.6.1</commons-math3.version>
         <decimal4j.version>1.0.3</decimal4j.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
 
         <assertj.version>3.6.1</assertj.version>
 

java-streams/pom.xml

@@ -106,7 +106,6 @@
 
     <properties>
         <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <vavr.version>0.9.0</vavr.version>
         <protonpack.version>1.15</protonpack.version>
         <streamex.version>0.6.5</streamex.version>

java-strings-2/README.MD

@@ -4,3 +4,4 @@
 - [Check If a String Contains a Substring](https://www.baeldung.com/java-string-contains-substring)
 - [Removing Stopwords from a String in Java](https://www.baeldung.com/java-string-remove-stopwords)
 - [Blank and Empty Strings in Java](https://www.baeldung.com/java-blank-empty-strings)
+- [String Initialization in Java](https://www.baeldung.com/java-string-initialization)

javax-servlets/pom.xml

@@ -88,7 +88,6 @@
         <assertj.version>3.9.1</assertj.version>
         <mockito.version>2.21.0</mockito.version>
         <commons-fileupload.version>1.3.3</commons-fileupload.version>
-        <commons-io.version>2.6</commons-io.version>
         <javax.servlet-api.version>4.0.1</javax.servlet-api.version>
     </properties>
 </project>

jaxb/pom.xml

@@ -130,8 +130,6 @@
         <!-- maven plugins -->
         <jaxb2-maven-plugin.version>2.3</jaxb2-maven-plugin.version>
         <istack-commons-runtime.version>3.0.2</istack-commons-runtime.version>
-        <commons-io.version>2.5</commons-io.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <lifecycle-mapping-plugin.version>1.0.0</lifecycle-mapping-plugin.version>
 
         <javax.activation.version>1.1</javax.activation.version>

jee-7/pom.xml

@@ -519,11 +519,9 @@
 		<tyrus.version>1.13</tyrus.version>
 		<jersey.version>2.25</jersey.version>
 		<arquillian-glassfish.version>1.0.0.Final</arquillian-glassfish.version>
-		<maven-war-plugin.version>2.6</maven-war-plugin.version>
 		<org.springframework.security.version>4.2.3.RELEASE</org.springframework.security.version>
 		<maven-surefire-plugin.version>2.21.0</maven-surefire-plugin.version>
 		<taglibs.standard.version>1.1.2</taglibs.standard.version>
-		<commons-io.version>2.4</commons-io.version>
 		<com.sun.faces.jsf.version>2.2.14</com.sun.faces.jsf.version>
 		<httpclient.version>4.5</httpclient.version>
 		<arquillian-drone-bom.version>2.0.1.Final</arquillian-drone-bom.version>

jee-kotlin/README.md

@@ -0,0 +1 @@
+### Relevant Articles:

jee-kotlin/pom.xml

@@ -0,0 +1,286 @@
+<?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/maven-v4_0_0.xsd">
+
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>jee-kotlin</artifactId>
+    <name>jee-kotlin</name>
+    <packaging>war</packaging>
+	
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-stdlib-jdk8</artifactId>
+            <version>${kotlin.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-test-junit</artifactId>
+            <version>${kotlin.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>javax</groupId>
+            <artifactId>javaee-api</artifactId>
+            <version>${javaee-api.version}</version>
+            <type>jar</type>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-annotations</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>${jackson.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jboss.arquillian.junit</groupId>
+            <artifactId>arquillian-junit-container</artifactId>
+            <version>${arquillian_core.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jboss.shrinkwrap.resolver</groupId>
+            <artifactId>shrinkwrap-resolver-depchain</artifactId>
+            <version>${shrinkwrap.version}</version>
+            <type>pom</type>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jboss.arquillian.extension</groupId>
+            <artifactId>arquillian-rest-client-impl-jersey</artifactId>
+            <version>${arquillian-rest-client.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-test</artifactId>
+            <version>${kotlin.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <sourceDirectory>src/main/kotlin</sourceDirectory>
+        <testSourceDirectory>src/test/kotlin</testSourceDirectory>
+
+        <plugins>
+            <plugin>
+                <groupId>org.jetbrains.kotlin</groupId>
+                <artifactId>kotlin-maven-plugin</artifactId>
+                <version>${kotlin.version}</version>
+                <executions>
+                    <execution>
+                        <id>compile</id>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>compile</goal>
+                        </goals>
+                    </execution>
+                    <execution>
+                        <id>test-compile</id>
+                        <phase>test-compile</phase>
+                        <goals>
+                            <goal>test-compile</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <jvmTarget>1.8</jvmTarget>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-war-plugin</artifactId>
+                <version>${maven-war-plugin.version}</version>
+                <configuration>
+                    <warSourceDirectory>webapp</warSourceDirectory>
+                    <warName>kotlin</warName>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>default-compile</id>
+                        <phase>none</phase>
+                    </execution>
+                    <execution>
+                        <id>default-testCompile</id>
+                        <phase>none</phase>
+                    </execution>
+                    <execution>
+                        <id>compile</id>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>compile</goal>
+                        </goals>
+                    </execution>
+                    <execution>
+                        <id>testCompile</id>
+                        <phase>test-compile</phase>
+                        <goals>
+                            <goal>testCompile</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.jboss.arquillian</groupId>
+                <artifactId>arquillian-bom</artifactId>
+                <version>${arquillian_core.version}</version>
+                <scope>import</scope>
+                <type>pom</type>
+            </dependency>
+            <dependency>
+                <groupId>org.jboss.arquillian.extension</groupId>
+                <artifactId>arquillian-drone-bom</artifactId>
+                <version>${arquillian-drone-bom.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <profiles>
+        <profile>
+            <id>wildfly-managed-arquillian</id>
+            <activation>
+                <activeByDefault>true</activeByDefault>
+            </activation>
+            <dependencies>
+                <dependency>
+                    <groupId>org.wildfly</groupId>
+                    <artifactId>wildfly-arquillian-container-embedded</artifactId>
+                    <version>${wildfly.version}</version>
+                </dependency>
+                <dependency>
+                    <groupId>org.wildfly</groupId>
+                    <artifactId>wildfly-embedded</artifactId>
+                    <version>${wildfly.version}</version>
+                </dependency>
+            </dependencies>
+            <build>
+                <plugins>
+                    <!-- You need the maven dependency plugin to download locally a zip with the server,
+                    unless you provide your own, it will download under the /target directory -->
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-dependency-plugin</artifactId>
+                        <version>${maven-dependency-plugin.version}</version>
+                        <executions>
+                            <execution>
+                                <id>unpack</id>
+                                <phase>process-test-classes</phase>
+                                <goals>
+                                    <goal>unpack</goal>
+                                </goals>
+                                <configuration>
+                                    <artifactItems>
+                                        <artifactItem>
+                                            <groupId>org.wildfly</groupId>
+                                            <artifactId>wildfly-dist</artifactId>
+                                            <version>${wildfly.version}</version>
+                                            <type>zip</type>
+                                            <overWrite>false</overWrite>
+                                            <outputDirectory>target</outputDirectory>
+                                        </artifactItem>
+                                    </artifactItems>
+                                </configuration>
+                            </execution>
+                        </executions>
+                    </plugin>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-surefire-plugin</artifactId>
+                        <version>${maven-surefire-plugin.version}</version>
+                        <configuration>
+                            <!-- Fork every test because it will launch a separate AS instance -->
+                            <forkMode>always</forkMode>
+                            <systemPropertyVariables>
+                                <java.util.logging.manager>org.jboss.logmanager.LogManager</java.util.logging.manager>
+                                <jboss.home>${project.basedir}/target/wildfly-${wildfly.version}</jboss.home>
+                                <module.path>${project.basedir}/target/wildfly-${wildfly.version}/modules</module.path>
+                            </systemPropertyVariables>
+                            <redirectTestOutputToFile>false</redirectTestOutputToFile>
+                        </configuration>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+        <profile>
+            <id>wildfly-remote-arquillian</id>
+            <dependencies>
+                <dependency>
+                    <groupId>org.jboss.resteasy</groupId>
+                    <artifactId>resteasy-client</artifactId>
+                    <version>${resteasy.version}</version>
+                    <scope>test</scope>
+                </dependency>
+                <dependency>
+                    <groupId>org.jboss.resteasy</groupId>
+                    <artifactId>resteasy-jaxb-provider</artifactId>
+                    <version>${resteasy.version}</version>
+                    <scope>test</scope>
+                </dependency>
+                <dependency>
+                    <groupId>org.jboss.resteasy</groupId>
+                    <artifactId>resteasy-json-p-provider</artifactId>
+                    <version>${resteasy.version}</version>
+                    <scope>test</scope>
+                </dependency>
+                <dependency>
+                    <groupId>org.wildfly.arquillian</groupId>
+                    <artifactId>wildfly-arquillian-container-remote</artifactId>
+                    <version>2.2.0.Final</version>
+                    <scope>test</scope>
+                </dependency>
+            </dependencies>
+        </profile>
+    </profiles>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <failOnMissingWebXml>false</failOnMissingWebXml>
+        <javaee-api.version>8.0</javaee-api.version>
+
+
+        <kotlin.version>1.3.41</kotlin.version>
+        <kotlin.code.style>official</kotlin.code.style>
+        <kotlin.compiler.incremental>true</kotlin.compiler.incremental>
+
+
+        <wildfly.version>8.2.1.Final</wildfly.version>
+        <maven-surefire-plugin.version>2.21.0</maven-surefire-plugin.version>
+        <maven-dependency-plugin.version>3.1.1</maven-dependency-plugin.version>
+
+        <arquillian_core.version>1.4.1.Final</arquillian_core.version>
+        <arquillian-drone-bom.version>2.0.1.Final</arquillian-drone-bom.version>
+        <arquillian-rest-client.version>1.0.0.Alpha4</arquillian-rest-client.version>
+
+        <resteasy.version>3.8.0.Final</resteasy.version>
+        <shrinkwrap.version>3.1.3</shrinkwrap.version>
+
+    </properties>
+</project>

jee-kotlin/src/main/kotlin/com/baeldung/jeekotlin/entity/Student.kt

@@ -0,0 +1,22 @@
+package com.baeldung.jeekotlin.entity
+
+import com.fasterxml.jackson.annotation.JsonProperty
+import javax.persistence.*
+
+@Entity
+data class Student constructor (
+
+    @SequenceGenerator(name = "student_id_seq", sequenceName = "student_id_seq", allocationSize = 1)
+    @GeneratedValue(generator = "student_id_seq", strategy = GenerationType.SEQUENCE)
+    @Id
+    var id: Long?,
+
+    var firstName: String,
+
+    var lastName: String
+
+) {
+    constructor() : this(null, "", "")
+
+    constructor(firstName: String, lastName: String) : this(null, firstName, lastName)
+}

jee-kotlin/src/main/kotlin/com/baeldung/jeekotlin/rest/ApplicationConfig.kt

@@ -0,0 +1,9 @@
+package com.baeldung.jeekotlin.rest
+
+import javax.ws.rs.ApplicationPath
+import javax.ws.rs.core.Application
+
+@ApplicationPath("/")
+class ApplicationConfig : Application() {
+    override fun getClasses() = setOf(StudentResource::class.java)
+}

jee-kotlin/src/main/kotlin/com/baeldung/jeekotlin/rest/StudentResource.kt

@@ -0,0 +1,42 @@
+package com.baeldung.jeekotlin.rest
+
+import com.baeldung.jeekotlin.entity.Student
+import com.baeldung.jeekotlin.service.StudentService
+import javax.inject.Inject
+import javax.ws.rs.*
+import javax.ws.rs.core.MediaType
+import javax.ws.rs.core.Response
+
+@Path("/student")
+open class StudentResource {
+
+    @Inject
+    private lateinit var service: StudentService
+
+    @POST
+    open fun create(student: Student): Response {
+        service.create(student)
+        return Response.ok().build()
+    }
+
+    @GET
+    @Path("/{id}")
+    open fun read(@PathParam("id") id: Long): Response {
+        val student  = service.read(id)
+        return Response.ok(student, MediaType.APPLICATION_JSON_TYPE).build()
+    }
+
+    @PUT
+    open fun update(student: Student): Response {
+        service.update(student)
+        return Response.ok(student, MediaType.APPLICATION_JSON_TYPE).build()
+    }
+
+    @DELETE
+    @Path("/{id}")
+    open fun delete(@PathParam("id") id: Long): Response {
+        service.delete(id)
+        return Response.noContent().build()
+    }
+
+}

jee-kotlin/src/main/kotlin/com/baeldung/jeekotlin/service/StudentService.kt

@@ -0,0 +1,21 @@
+package com.baeldung.jeekotlin.service
+
+import com.baeldung.jeekotlin.entity.Student
+import javax.ejb.Stateless
+import javax.persistence.EntityManager
+import javax.persistence.PersistenceContext
+
+@Stateless
+open class StudentService {
+
+    @PersistenceContext
+    private lateinit var entityManager: EntityManager
+
+    open fun create(student: Student) = entityManager.persist(student)
+
+    open fun read(id: Long): Student? = entityManager.find(Student::class.java, id)
+
+    open fun update(student: Student) = entityManager.merge(student)
+
+    open fun delete(id: Long) = entityManager.remove(read(id))
+}

jee-kotlin/src/main/resources/META-INF/persistence.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="2.0">
+
+  <persistence-unit name="pu" transaction-type="JTA">
+
+    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+
+    <jta-data-source>java:jboss/datasources/ExampleDS</jta-data-source>
+
+    <class>com.enpy.entity.Student</class>
+
+    <properties>
+      <property name="hibernate.hbm2ddl.auto" value="create"/>
+    </properties>
+
+  </persistence-unit>
+
+</persistence>

jee-kotlin/src/main/webapp/WEB-INF/beans.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans
+    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
+                      http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
+    bean-discovery-mode="all">
+</beans>

jee-kotlin/src/test/kotlin/com/baeldung/jeekotlin/StudentResourceIntegrationTest.java

@@ -0,0 +1,108 @@
+package com.baeldung.jeekotlin;
+
+import com.baeldung.jeekotlin.entity.Student;
+import org.jboss.arquillian.container.test.api.Deployment;
+import org.jboss.arquillian.container.test.api.RunAsClient;
+import org.jboss.arquillian.test.api.ArquillianResource;
+import org.jboss.arquillian.junit.Arquillian;
+import org.jboss.shrinkwrap.api.Filters;
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.asset.EmptyAsset;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.jboss.shrinkwrap.api.spec.WebArchive;
+import org.jboss.shrinkwrap.resolver.api.maven.Maven;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import javax.ws.rs.client.Entity;
+import javax.ws.rs.client.ClientBuilder;
+import javax.ws.rs.client.WebTarget;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+import java.net.URISyntaxException;
+import java.net.URL;
+
+import static org.junit.Assert.assertEquals;
+
+@RunWith(Arquillian.class)
+public class StudentResourceIntegrationTest {
+
+    @Deployment
+    public static WebArchive createDeployment() {
+        JavaArchive[] kotlinRuntime = Maven.configureResolver()
+                .workOffline()
+                .withMavenCentralRepo(true)
+                .withClassPathResolution(true)
+                .loadPomFromFile("pom.xml")
+                .resolve("org.jetbrains.kotlin:kotlin-stdlib")
+                .withTransitivity()
+                .as(JavaArchive.class);
+
+        return ShrinkWrap.create(WebArchive.class, "kotlin.war")
+                .addPackages(true, Filters.exclude(".*Test*"),
+                        "com.baeldung.jeekotlin"
+                )
+                .addAsLibraries(kotlinRuntime)
+                .addAsResource("META-INF/persistence.xml")
+                .addAsManifestResource(EmptyAsset.INSTANCE, "beans.xml");
+    }
+
+    @Test
+    @RunAsClient
+    public void when_post__then_return_ok(@ArquillianResource URL url) throws URISyntaxException, JsonProcessingException {
+        String student = new ObjectMapper().writeValueAsString(new Student("firstName", "lastName"));
+        WebTarget webTarget = ClientBuilder.newClient().target(url.toURI());
+
+        Response response = webTarget
+                .path("/student")
+                .request(MediaType.APPLICATION_JSON)
+                .post(Entity.json(student));
+
+        assertEquals(200, response.getStatus());
+    }
+
+    @Test
+    @RunAsClient
+    public void when_get__then_return_ok(@ArquillianResource URL url) throws URISyntaxException, JsonProcessingException {
+        WebTarget webTarget = ClientBuilder.newClient().target(url.toURI());
+
+        Response response = webTarget
+                .path("/student/1")
+                .request(MediaType.APPLICATION_JSON)
+                .get();
+
+        assertEquals(200, response.getStatus());
+    }
+
+    @Test
+    @RunAsClient
+    public void when_put__then_return_ok(@ArquillianResource URL url) throws URISyntaxException, JsonProcessingException {
+        Student student = new Student("firstName", "lastName");
+        student.setId(1L);
+        String studentJson = new ObjectMapper().writeValueAsString(student);
+        WebTarget webTarget = ClientBuilder.newClient().target(url.toURI());
+
+        Response response = webTarget
+                .path("/student")
+                .request(MediaType.APPLICATION_JSON)
+                .put(Entity.json(studentJson));
+
+        assertEquals(200, response.getStatus());
+    }
+
+    @Test
+    @RunAsClient
+    public void when_delete__then_return_ok(@ArquillianResource URL url) throws URISyntaxException, JsonProcessingException {
+        WebTarget webTarget = ClientBuilder.newClient().target(url.toURI());
+
+        Response response = webTarget
+                .path("/student/1")
+                .request()
+                .delete();
+
+        assertEquals(204, response.getStatus());
+    }
+
+}

jee-kotlin/src/test/resources/arquillian.xml

@@ -0,0 +1,22 @@
+<arquillian xmlns="http://jboss.org/schema/arquillian" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://jboss.org/schema/arquillian http://jboss.org/schema/arquillian/arquillian_1_0.xsd">
+
+    <container qualifier="wildfly-managed">
+        <configuration>
+            <property name="jbossHome">target/wildfly-8.2.1.Final</property>
+            <property name="serverConfig">standalone.xml</property>
+            <property name="outputToConsole">true</property>
+            <property name="managementPort">9990</property>
+        </configuration>
+    </container>
+
+    <container qualifier="wildfly-remote" default="true">
+        <configuration>
+            <property name="managementAddress">127.0.0.1</property>
+            <property name="managementPort">9990</property>
+            <property name="username">admin</property>
+            <property name="password">pass</property>
+            <property name="allowConnectingToRunningServer">true</property>
+        </configuration>
+    </container>
+
+</arquillian>

jersey/pom.xml

@@ -80,7 +80,6 @@
 
     <properties>
         <jersey.version>2.26</jersey.version>
-        <maven-war-plugin.version>3.2.0</maven-war-plugin.version>
     </properties>
 
 </project>

jsf/pom.xml

@@ -99,9 +99,6 @@
         <com.sun.faces.version>2.2.14</com.sun.faces.version>
         <javax.el.version>3.0.0</javax.el.version>
 
-        <!-- maven plugins -->
-        <maven-war-plugin.version>2.6</maven-war-plugin.version>
-
         <primefaces.version>6.2</primefaces.version>
     </properties>
 

jws/pom.xml

@@ -83,7 +83,6 @@
 
     <properties>
         <maven-jar-plugin.version>3.0.2</maven-jar-plugin.version>
-        <maven-war-plugin.version>3.0.0</maven-war-plugin.version>
         <jnlp-jardiff.version>1.6.0</jnlp-jardiff.version>
         <jnlp-servlet.version>1.6.0</jnlp-servlet.version>
     </properties>

kotlin-libraries/pom.xml

@@ -94,7 +94,7 @@
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
-            <version>${h2database.version}</version>
+            <version>${h2.version}</version>
         </dependency>
         <!-- https://mvnrepository.com/artifact/io.arrow-kt/arrow-core -->
         <dependency>
@@ -184,7 +184,6 @@
         <junit.platform.version>1.1.1</junit.platform.version>
         <junit.vintage.version>5.2.0</junit.vintage.version>
         <assertj.version>3.10.0</assertj.version>
-        <h2database.version>1.4.197</h2database.version>
         <exposed.version>0.10.4</exposed.version>
         <mockk.version>1.9.3</mockk.version>
     </properties>

kotlin-quasar/pom.xml

@@ -8,6 +8,12 @@
     <name>kotlin-quasar</name>
     <packaging>jar</packaging>
 
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
     <dependencies>
         <dependency>
             <groupId>org.jetbrains.kotlin</groupId>
@@ -45,6 +51,27 @@
             <artifactId>junit</artifactId>
             <version>4.12</version>
         </dependency>
+		<!-- logging -->
+		<dependency>
+			<groupId>org.slf4j</groupId>
+			<artifactId>slf4j-api</artifactId>
+			<version>${org.slf4j.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>ch.qos.logback</groupId>
+			<artifactId>logback-classic</artifactId>
+			<version>${logback.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>ch.qos.logback</groupId>
+			<artifactId>logback-core</artifactId>
+			<version>${logback.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.slf4j</groupId>
+			<artifactId>jcl-over-slf4j</artifactId>
+			<version>${org.slf4j.version}</version>
+		</dependency>
     </dependencies>
 
     <build>
@@ -116,5 +143,7 @@
     <properties>
         <quasar.version>0.8.0</quasar.version>
         <kotlin.version>1.3.31</kotlin.version>
+		<org.slf4j.version>1.7.21</org.slf4j.version>
+		<logback.version>1.1.7</logback.version>
     </properties>
 </project>

kotlin-quasar/src/test/kotlin/com/baeldung/quasar/ActorsBehaviorTest.kt

@@ -0,0 +1,157 @@
+package com.baeldung.quasar
+
+import co.paralleluniverse.actors.Actor
+import co.paralleluniverse.actors.ActorRef
+import co.paralleluniverse.actors.behaviors.*
+import co.paralleluniverse.fibers.Suspendable
+import co.paralleluniverse.strands.SuspendableCallable
+import org.junit.Test
+import org.slf4j.LoggerFactory
+import java.lang.Exception
+
+class ActorsBehaviorTest {
+    companion object {
+        private val LOG = LoggerFactory.getLogger(ActorsBehaviorTest::class.java)
+    }
+
+    @Test
+    fun requestReplyHelper() {
+        data class TestMessage(val input: Int) : RequestMessage<Int>()
+
+        val actor = object : Actor<TestMessage, Void>("requestReplyActor", null) {
+            @Suspendable
+            override fun doRun(): Void? {
+                while (true) {
+                    val msg = receive()
+                    LOG.info("Processing message: {}", msg)
+
+                    RequestReplyHelper.reply(msg, msg.input * 100)
+                }
+            }
+        }
+
+        val actorRef = actor.spawn()
+
+        val result = RequestReplyHelper.call(actorRef, TestMessage(50))
+        LOG.info("Received reply: {}", result)
+    }
+
+    @Test
+    fun server() {
+        val actor = ServerActor(object : AbstractServerHandler<Int, String, Float>() {
+            @Suspendable
+            override fun handleCall(from: ActorRef<*>?, id: Any?, m: Int?): String {
+                LOG.info("Called with message: {} from {} with ID {}", m, from, id)
+                return m.toString() ?: "None"
+            }
+
+            @Suspendable
+            override fun handleCast(from: ActorRef<*>?, id: Any?, m: Float?) {
+                LOG.info("Cast message: {} from {} with ID {}", m, from, id)
+            }
+        })
+
+        val server = actor.spawn()
+
+        LOG.info("Call result: {}", server.call(5))
+        server.cast(2.5f)
+
+        server.shutdown()
+    }
+
+    interface Summer {
+        fun sum(a: Int, b: Int) : Int
+    }
+
+    @Test
+    fun proxyServer() {
+        val actor = ProxyServerActor(false, object : Summer {
+            @Synchronized
+            override fun sum(a: Int, b: Int): Int {
+                Exception().printStackTrace()
+                LOG.info("Adding together {} and {}", a, b)
+                return a + b
+            }
+        })
+
+        val summerActor = actor.spawn()
+
+        val result = (summerActor as Summer).sum(1, 2)
+        LOG.info("Result: {}", result)
+
+        summerActor.shutdown()
+    }
+
+    @Test
+    fun eventSource() {
+        val actor = EventSourceActor<String>()
+        val eventSource = actor.spawn()
+
+        eventSource.addHandler { msg ->
+            LOG.info("Sent message: {}", msg)
+        }
+
+        val name = "Outside Value"
+        eventSource.addHandler { msg ->
+            LOG.info("Also Sent message: {} {}", msg, name)
+        }
+
+        eventSource.send("Hello")
+
+        eventSource.shutdown()
+    }
+
+    @Test
+    fun finiteStateMachine() {
+        val actor = object : FiniteStateMachineActor() {
+            @Suspendable
+            override fun initialState(): SuspendableCallable<SuspendableCallable<*>> {
+                LOG.info("Starting")
+                return SuspendableCallable { lockedState() }
+            }
+
+            @Suspendable
+            fun lockedState() : SuspendableCallable<SuspendableCallable<*>> {
+                return receive {msg ->
+                    when (msg) {
+                        "PUSH" -> {
+                            LOG.info("Still locked")
+                            lockedState()
+                        }
+                        "COIN" -> {
+                            LOG.info("Unlocking...")
+                            unlockedState()
+                        }
+                        else -> TERMINATE
+                    }
+                }
+            }
+
+            @Suspendable
+            fun unlockedState() : SuspendableCallable<SuspendableCallable<*>> {
+                return receive {msg ->
+                    when (msg) {
+                        "PUSH" -> {
+                            LOG.info("Locking")
+                            lockedState()
+                        }
+                        "COIN" -> {
+                            LOG.info("Unlocked")
+                            unlockedState()
+                        }
+                        else -> TERMINATE
+                    }
+                }
+            }
+        }
+
+        val actorRef = actor.spawn()
+
+        listOf("PUSH", "COIN", "COIN", "PUSH", "PUSH").forEach {
+            LOG.info(it)
+            actorRef.sendSync(it)
+        }
+
+        actorRef.shutdown()
+    }
+}

kotlin-quasar/src/test/kotlin/com/baeldung/quasar/ActorsTest.kt

@@ -0,0 +1,298 @@
+package com.baeldung.quasar
+
+import co.paralleluniverse.actors.*
+import co.paralleluniverse.fibers.Suspendable
+import co.paralleluniverse.strands.channels.Channels
+import org.junit.Assert
+import org.junit.Test
+import org.slf4j.LoggerFactory
+import java.util.concurrent.TimeUnit
+
+class ActorsTest {
+    companion object {
+        private val LOG = LoggerFactory.getLogger(ActorsTest::class.java)
+    }
+
+    @Test
+    fun createNoopActor() {
+        val actor = object : Actor<Int, String>("noopActor", MailboxConfig(5, Channels.OverflowPolicy.THROW)) {
+            @Suspendable
+            override fun doRun(): String {
+                return "Hello"
+            }
+        }
+
+        actor.spawn()
+
+        println("Noop Actor: ${actor.get()}")
+    }
+
+    @Test
+    fun registerActor() {
+        val actor = object : Actor<Int, String>("registerActor", null) {
+            @Suspendable
+            override fun doRun(): String {
+                return "Hello"
+            }
+        }
+
+        val actorRef = actor.spawn()
+        actor.register()
+
+        val retrievedRef = ActorRegistry.getActor<ActorRef<Int>>("registerActor")
+
+        Assert.assertEquals(actorRef, retrievedRef)
+        actor.join()
+    }
+
+    @Test
+    fun registerActorNewName() {
+        val actor = object : Actor<Int, String>(null, null) {
+            @Suspendable
+            override fun doRun(): String {
+                return "Hello"
+            }
+        }
+
+        val actorRef = actor.spawn()
+        actor.register("renamedActor")
+
+        val retrievedRef = ActorRegistry.getActor<ActorRef<Int>>("renamedActor")
+
+        Assert.assertEquals(actorRef, retrievedRef)
+        actor.join()
+    }
+
+    @Test
+    fun retrieveUnknownActor() {
+        val retrievedRef = ActorRegistry.getActor<ActorRef<Int>>("unknownActor", 1, TimeUnit.SECONDS)
+
+        Assert.assertNull(retrievedRef)
+    }
+
+    @Test
+    fun createSimpleActor() {
+        val actor = object : Actor<Int, Void?>("simpleActor", null) {
+            @Suspendable
+            override fun doRun(): Void? {
+                val msg = receive()
+                LOG.info("SimpleActor Received Message: {}", msg)
+
+                return null
+            }
+        }
+
+        val actorRef = actor.spawn()
+
+        actorRef.send(1)
+
+        actor.join()
+    }
+
+    @Test
+    fun createLoopingActor() {
+        val actor = object : Actor<Int, Void?>("loopingActor", null) {
+            @Suspendable
+            override fun doRun(): Void? {
+                while (true) {
+                    val msg = receive()
+
+                    if (msg > 0) {
+                        LOG.info("LoopingActor Received Message: {}", msg)
+                    } else {
+                        break
+                    }
+                }
+
+                return null
+            }
+        }
+
+        val actorRef = actor.spawn()
+
+        actorRef.send(3)
+        actorRef.send(2)
+        actorRef.send(1)
+        actorRef.send(0)
+
+        actor.join()
+    }
+
+    @Test
+    fun actorBacklog() {
+        val actor = object : Actor<Int, String>("backlogActor", MailboxConfig(1, Channels.OverflowPolicy.THROW)) {
+            @Suspendable
+            override fun doRun(): String {
+                TimeUnit.MILLISECONDS.sleep(500);
+                LOG.info("Backlog Actor Received: {}", receive())
+
+                try {
+                    receive()
+                } catch (e: Throwable) {
+                    LOG.info("==== Exception throws by receive() ====")
+                    e.printStackTrace()
+                }
+
+                return "No Exception"
+            }
+        }
+
+        val actorRef = actor.spawn()
+
+        actorRef.send(1)
+        actorRef.send(2)
+
+        try {
+            LOG.info("Backlog Actor: {}", actor.get())
+        } catch (e: Exception) {
+            // Expected
+            LOG.info("==== Exception throws by get() ====")
+            e.printStackTrace()
+        }
+    }
+
+    @Test
+    fun actorBacklogTrySend() {
+        val actor = object : Actor<Int, String>("backlogTrySendActor", MailboxConfig(1, Channels.OverflowPolicy.THROW)) {
+            @Suspendable
+            override fun doRun(): String {
+                TimeUnit.MILLISECONDS.sleep(500);
+                LOG.info("Backlog TrySend Actor Received: {}", receive())
+
+                return "No Exception"
+            }
+        }
+
+        val actorRef = actor.spawn()
+
+        LOG.info("Backlog TrySend 1: {}", actorRef.trySend(1))
+        LOG.info("Backlog TrySend 1: {}", actorRef.trySend(2))
+
+        actor.join()
+    }
+
+    @Test
+    fun actorTimeoutReceive() {
+        val actor = object : Actor<Int, String>("TimeoutReceiveActor", MailboxConfig(1, Channels.OverflowPolicy.THROW)) {
+            @Suspendable
+            override fun doRun(): String {
+                LOG.info("Timeout Actor Received: {}", receive(500, TimeUnit.MILLISECONDS))
+
+                return "Finished"
+            }
+        }
+
+        val actorRef = actor.spawn()
+
+        TimeUnit.MILLISECONDS.sleep(300)
+        actorRef.trySend(1)
+
+        actor.join()
+    }
+
+
+    @Test
+    fun actorNonBlockingReceive() {
+        val actor = object : Actor<Int, String>("NonBlockingReceiveActor", MailboxConfig(1, Channels.OverflowPolicy.THROW)) {
+            @Suspendable
+            override fun doRun(): String {
+                LOG.info("NonBlocking Actor Received #1: {}", tryReceive())
+                TimeUnit.MILLISECONDS.sleep(500)
+                LOG.info("NonBlocking Actor Received #2: {}", tryReceive())
+
+                return "Finished"
+            }
+        }
+
+        val actorRef = actor.spawn()
+
+        TimeUnit.MILLISECONDS.sleep(300)
+        actorRef.trySend(1)
+
+        actor.join()
+    }
+
+    @Test
+    fun evenActor() {
+        val actor = object : Actor<Int, Void?>("EvenActor", null) {
+            @Suspendable
+            override fun filterMessage(m: Any?): Int? {
+                return when (m) {
+                    is Int -> {
+                        if (m % 2 == 0) {
+                            m * 10
+                        } else {
+                            null
+                        }
+                    }
+                    else -> super.filterMessage(m)
+                }
+            }
+
+            @Suspendable
+            override fun doRun(): Void? {
+                while (true) {
+                    val msg = receive()
+
+                    if (msg > 0) {
+                        LOG.info("EvenActor Received Message: {}", msg)
+                    } else {
+                        break
+                    }
+                }
+
+                return null
+            }
+        }
+
+        val actorRef = actor.spawn()
+
+        actorRef.send(3)
+        actorRef.send(2)
+        actorRef.send(1)
+        actorRef.send(0)
+
+        actor.join()
+    }
+
+    @Test
+    fun watchingActors() {
+        val watched = object : Actor<Int, Void?>("WatchedActor", null) {
+            @Suspendable
+            override fun doRun(): Void? {
+                LOG.info("WatchedActor Starting")
+                receive(500, TimeUnit.MILLISECONDS)
+                LOG.info("WatchedActor Finishing")
+                return null
+            }
+        }
+
+        val watcher = object : Actor<Int, Void?>("WatcherActor", null) {
+            @Suspendable
+            override fun doRun(): Void? {
+                LOG.info("WatcherActor Listening")
+                try {
+                    LOG.info("WatcherActor received Message: {}", receive(2, TimeUnit.SECONDS))
+                } catch (e: Exception) {
+                    LOG.info("WatcherActor Received Exception", e)
+                }
+                return null
+            }
+
+            @Suspendable
+            override fun handleLifecycleMessage(m: LifecycleMessage?): Int? {
+                LOG.info("WatcherActor Received Lifecycle Message: {}", m)
+                return super.handleLifecycleMessage(m)
+            }
+        }
+
+        val watcherRef = watcher.spawn()
+        TimeUnit.MILLISECONDS.sleep(200)
+
+        val watchedRef = watched.spawn()
+        watcher.link(watchedRef)
+
+        watched.join()
+        watcher.join()
+    }
+}

kotlin-quasar/src/test/kotlin/com/baeldung/quasar/ReactiveStreamsTest.kt

@@ -0,0 +1,135 @@
+package com.baeldung.quasar
+
+import co.paralleluniverse.fibers.Suspendable
+import co.paralleluniverse.kotlin.fiber
+import co.paralleluniverse.strands.channels.Channels
+import co.paralleluniverse.strands.channels.Topic
+import co.paralleluniverse.strands.channels.reactivestreams.ReactiveStreams
+import org.junit.Test
+import org.reactivestreams.Subscriber
+import org.reactivestreams.Subscription
+import org.slf4j.LoggerFactory
+import java.util.concurrent.TimeUnit
+
+class ReactiveStreamsTest {
+    companion object {
+        private val LOG = LoggerFactory.getLogger(ReactiveStreamsTest::class.java)
+    }
+
+    @Test
+    fun publisher() {
+        val inputChannel = Channels.newChannel<String>(1);
+
+        val publisher = ReactiveStreams.toPublisher(inputChannel)
+        publisher.subscribe(object : Subscriber<String> {
+            @Suspendable
+            override fun onComplete() {
+                LOG.info("onComplete")
+            }
+
+            @Suspendable
+            override fun onSubscribe(s: Subscription) {
+                LOG.info("onSubscribe: {}", s)
+                s.request(2)
+            }
+
+            @Suspendable
+            override fun onNext(t: String?) {
+                LOG.info("onNext: {}", t)
+            }
+
+            @Suspendable
+            override fun onError(t: Throwable?) {
+                LOG.info("onError: {}", t)
+            }
+        })
+
+        inputChannel.send("Hello")
+        inputChannel.send("World")
+
+        TimeUnit.SECONDS.sleep(1)
+
+        inputChannel.close()
+    }
+
+    @Test
+    fun publisherTopic() {
+        val inputTopic = Topic<String>()
+
+        val publisher = ReactiveStreams.toPublisher(inputTopic)
+        publisher.subscribe(object : Subscriber<String> {
+            @Suspendable
+            override fun onComplete() {
+                LOG.info("onComplete 1")
+            }
+
+            @Suspendable
+            override fun onSubscribe(s: Subscription) {
+                LOG.info("onSubscribe 1: {}", s)
+                s.request(2)
+            }
+
+            @Suspendable
+            override fun onNext(t: String?) {
+                LOG.info("onNext 1: {}", t)
+            }
+
+            @Suspendable
+            override fun onError(t: Throwable?) {
+                LOG.info("onError 1: {}", t)
+            }
+        })
+        publisher.subscribe(object : Subscriber<String> {
+            @Suspendable
+            override fun onComplete() {
+                LOG.info("onComplete 2")
+            }
+
+            @Suspendable
+            override fun onSubscribe(s: Subscription) {
+                LOG.info("onSubscribe 2: {}", s)
+                s.request(2)
+            }
+
+            @Suspendable
+            override fun onNext(t: String?) {
+                LOG.info("onNext 2: {}", t)
+            }
+
+            @Suspendable
+            override fun onError(t: Throwable?) {
+                LOG.info("onError 2: {}", t)
+            }
+        })
+
+        inputTopic.send("Hello")
+        inputTopic.send("World")
+
+        TimeUnit.SECONDS.sleep(1)
+
+        inputTopic.close()
+    }
+
+    @Test
+    fun subscribe() {
+        val inputChannel = Channels.newChannel<String>(10);
+        val publisher = ReactiveStreams.toPublisher(inputChannel)
+
+        val channel = ReactiveStreams.subscribe(10, Channels.OverflowPolicy.THROW, publisher)
+
+        fiber @Suspendable {
+            while (!channel.isClosed) {
+                val message = channel.receive()
+                LOG.info("Received: {}", message)
+            }
+            LOG.info("Stopped receiving messages")
+        }
+
+        inputChannel.send("Hello")
+        inputChannel.send("World")
+
+        TimeUnit.SECONDS.sleep(1)
+
+        inputChannel.close()
+    }
+}

libraries-apache-commons/pom.xml

@@ -25,7 +25,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>${commons-lang.version}</version>
+            <version>${commons-lang3.version}</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
@@ -35,7 +35,7 @@
         <dependency>
             <groupId>commons-io</groupId>
             <artifactId>commons-io</artifactId>
-            <version>${commons.io.version}</version>
+            <version>${commons-io.version}</version>
         </dependency>
         <dependency>
             <groupId>commons-chain</groupId>
@@ -87,13 +87,12 @@
     </dependencies>
 
     <properties>
-        <commons-lang.version>3.6</commons-lang.version>
+        <commons-lang3.version>3.6</commons-lang3.version>
         <commons-text.version>1.1</commons-text.version>
         <commons-beanutils.version>1.9.3</commons-beanutils.version>
         <commons-chain.version>1.2</commons-chain.version>
         <commons-csv.version>1.4</commons-csv.version>
         <assertj.version>3.6.2</assertj.version>
-        <commons.io.version>2.5</commons.io.version>
         <commons.dbutils.version>1.6</commons.dbutils.version>
         <commons.collections.version>4.1</commons.collections.version>
         <org.hamcrest.java-hamcrest.version>2.0.0.0</org.hamcrest.java-hamcrest.version>

libraries-data/pom.xml

@@ -449,7 +449,6 @@
         <gson.version>2.8.2</gson.version>
         <cache.version>1.1.0</cache.version>
         <flink.version>1.5.0</flink.version>
-        <jackson.version>2.9.7</jackson.version>
         <awaitility.version>3.0.0</awaitility.version>
         <assertj.version>3.6.2</assertj.version>
         <hazelcast.version>3.8.4</hazelcast.version>

libraries-server/pom.xml

@@ -52,7 +52,7 @@
         <dependency>
             <groupId>commons-io</groupId>
             <artifactId>commons-io</artifactId>
-            <version>${commons.io.version}</version>
+            <version>${commons-io.version}</version>
         </dependency>
         <dependency>
             <groupId>io.netty</groupId>
@@ -114,7 +114,6 @@
     <properties>
         <assertj.version>3.6.2</assertj.version>
         <httpclient.version>4.5.3</httpclient.version>
-        <commons.io.version>2.5</commons.io.version>
         <jetty.version>9.4.8.v20171121</jetty.version>
         <netty.version>4.1.20.Final</netty.version>
         <commons.collections.version>4.1</commons.collections.version>

libraries/pom.xml

@@ -45,7 +45,7 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>${commons-lang.version}</version>
+            <version>${commons-lang3.version}</version>
         </dependency>
         <dependency>
             <groupId>commons-net</groupId>
@@ -818,7 +818,6 @@
         <crdt.version>0.1.0</crdt.version>
         <multiverse.version>0.7.0</multiverse.version>
         <cglib.version>3.2.7</cglib.version>
-        <commons-lang.version>3.6</commons-lang.version>
         <jasypt.version>1.9.2</jasypt.version>
         <javatuples.version>1.2</javatuples.version>
         <javaassist.version>3.21.0-GA</javaassist.version>
@@ -826,12 +825,10 @@
         <jsonassert.version>1.5.0</jsonassert.version>
         <javers.version>3.1.0</javers.version>
         <httpclient.version>4.5.3</httpclient.version>
-        <h2.version>1.4.196</h2.version>
         <jnats.version>1.0</jnats.version>
 
 
         <httpclient.version>4.5.3</httpclient.version>
-        <jackson.version>2.9.7</jackson.version>
         <neuroph.version>2.92</neuroph.version>
         <serenity.version>1.9.26</serenity.version>
         <serenity.jbehave.version>1.41.0</serenity.jbehave.version>

logging-modules/log-mdc/pom.xml

@@ -101,7 +101,6 @@
         <log4j2.version>2.7</log4j2.version>
         <disruptor.version>3.3.6</disruptor.version>
         <jbosslogging.version>3.3.0.Final</jbosslogging.version>
-        <maven-war-plugin.version>2.4</maven-war-plugin.version>
     </properties>
 
 </project>

maven-polyglot/maven-polyglot-json-app/pom.json

@@ -5,10 +5,10 @@
   "version": "1.0-SNAPSHOT",
   "name": "Json Maven Polyglot",
   "parent": {
-    "groupId": "org.springframework.boot",
-    "artifactId": "spring-boot-starter-parent",
-    "version": "2.0.5.RELEASE",
-    "relativePath": null
+    "groupId": "com.baeldung",
+    "artifactId": "parent-boot-2",
+    "version": "0.0.1-SNAPSHOT",
+    "relativePath": "../../parent-boot-2"
   },
   "properties": {
     "project.build.sourceEncoding": "UTF-8",

maven-polyglot/maven-polyglot-json-extension/pom.xml

@@ -8,17 +8,24 @@
     <version>1.0-SNAPSHOT</version>
 	<name>maven-polyglot-json-extension</name>
 
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../..</relativePath>
+    </parent>
+
     <dependencies>
         <dependency>
             <groupId>org.apache.maven</groupId>
             <artifactId>maven-core</artifactId>
-            <version>3.5.4</version>
+            <version>${maven-core.version}</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
-            <version>2.9.6</version>
+            <version>${jackson.version}</version>
         </dependency>
     </dependencies>
 
@@ -42,6 +49,7 @@
     <properties>
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
+        <maven-core.version>3.5.4</maven-core.version>
     </properties>
 
 </project>

maven-polyglot/maven-polyglot-yml-app/pom.yml

@@ -4,4 +4,10 @@ artifactId: maven-polyglot-yml-app
 version: 1.0-SNAPSHOT
 name: 'YAML Demo'
 
+parent: 
+  groupId: "com.baeldung"
+  artifactId: "parent-modules"
+  version: "1.0.0-SNAPSHOT"
+  relativePath: "../.."
+
 properties: {maven.compiler.source: 1.8, maven.compiler.target: 1.8}

maven/pom.xml

@@ -7,6 +7,12 @@
     <name>maven</name>
     <packaging>pom</packaging>
 
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
     <modules>
         <module>custom-rule</module>
         <module>maven-enforcer</module>
@@ -293,7 +299,6 @@
     </profiles>
 
     <properties>
-        <java.version>1.8</java.version>
         <maven.resources.version>3.0.2</maven.resources.version>
         <maven.compiler.version>3.8.0</maven.compiler.version>
         <maven.surefire.version>2.22.0</maven.surefire.version>
@@ -304,6 +309,5 @@
         <resources.name>Baeldung</resources.name>
         <jetty.version>9.4.11.v20180605</jetty.version>
         <jersey.version>2.27</jersey.version>
-        <junit.version>4.12</junit.version>
     </properties>
 </project>

oauth2-framework-impl/oauth2-authorization-server/pom.xml

@@ -0,0 +1,72 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project 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">
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>oauth2-authorization-server</artifactId>
+    <packaging>war</packaging>
+
+    <parent>
+        <groupId>com.baeldung.oauth2</groupId>
+        <artifactId>oauth2-framework-impl</artifactId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+
+    <properties>
+        <h2.version>1.4.199</h2.version>
+        <httpPort>9080</httpPort>
+        <httpsPort>9443</httpsPort>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.nimbusds</groupId>
+            <artifactId>nimbus-jose-jwt</artifactId>
+            <version>7.3</version>
+        </dependency>
+        <dependency>
+            <groupId>org.bouncycastle</groupId>
+            <artifactId>bcprov-jdk15on</artifactId>
+            <version>1.62</version>
+        </dependency>
+        <dependency>
+            <groupId>org.bouncycastle</groupId>
+            <artifactId>bcpkix-jdk15on</artifactId>
+            <version>1.62</version>
+        </dependency>
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>net.wasdev.wlp.maven.plugins</groupId>
+                <artifactId>liberty-maven-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-dependency-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>copy-h2-dependency</id>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>copy</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <artifactItems>
+                        <artifactItem>
+                            <groupId>com.h2database</groupId>
+                            <artifactId>h2</artifactId>
+                            <version>${h2.version}</version>
+                            <type>jar</type>
+                            <outputDirectory>${project.build.directory}/liberty/wlp/usr/shared/resources/
+                            </outputDirectory>
+                        </artifactItem>
+                    </artifactItems>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>

oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/OAuth2ServerApplication.java

@@ -0,0 +1,8 @@
+package com.baeldung.oauth2.authorization.server;
+
+import javax.ws.rs.ApplicationPath;
+import javax.ws.rs.core.Application;
+
+@ApplicationPath("/")
+public class OAuth2ServerApplication extends Application {
+}

oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/PEMKeyUtils.java

@@ -0,0 +1,17 @@
+package com.baeldung.oauth2.authorization.server;
+
+import java.net.URI;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static java.lang.Thread.currentThread;
+
+
+public class PEMKeyUtils {
+
+    public static String readKeyAsString(String keyLocation) throws Exception {
+        URI uri = currentThread().getContextClassLoader().getResource(keyLocation).toURI();
+        byte[] byteArray = Files.readAllBytes(Paths.get(uri));
+        return new String(byteArray);
+    }
+}

oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/api/AuthorizationEndpoint.java

@@ -0,0 +1,185 @@
+package com.baeldung.oauth2.authorization.server.api;
+
+import com.baeldung.oauth2.authorization.server.handler.AuthorizationGrantTypeHandler;
+import com.baeldung.oauth2.authorization.server.model.AppDataRepository;
+import com.baeldung.oauth2.authorization.server.model.AuthorizationCode;
+import com.baeldung.oauth2.authorization.server.model.Client;
+import com.baeldung.oauth2.authorization.server.model.User;
+
+import javax.annotation.security.RolesAllowed;
+import javax.enterprise.context.RequestScoped;
+import javax.enterprise.inject.Instance;
+import javax.enterprise.inject.literal.NamedLiteral;
+import javax.inject.Inject;
+import javax.json.JsonObject;
+import javax.security.enterprise.SecurityContext;
+import javax.security.enterprise.authentication.mechanism.http.FormAuthenticationMechanismDefinition;
+import javax.security.enterprise.authentication.mechanism.http.LoginToContinue;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.ws.rs.*;
+import javax.ws.rs.core.*;
+import java.io.IOException;
+import java.net.URI;
+import java.security.Principal;
+import java.time.LocalDateTime;
+import java.util.*;
+
+@FormAuthenticationMechanismDefinition(
+        loginToContinue = @LoginToContinue(loginPage = "/login.jsp", errorPage = "/login.jsp")
+)
+@RolesAllowed("USER")
+@RequestScoped
+@Path("authorize")
+public class AuthorizationEndpoint {
+
+    @Inject
+    private SecurityContext securityContext;
+
+    @Inject
+    private AppDataRepository appDataRepository;
+
+    @Inject
+    Instance<AuthorizationGrantTypeHandler> authorizationGrantTypeHandlers;
+
+    @GET
+    @Produces(MediaType.TEXT_HTML)
+    public Response doGet(@Context HttpServletRequest request,
+                          @Context HttpServletResponse response,
+                          @Context UriInfo uriInfo) throws ServletException, IOException {
+        MultivaluedMap<String, String> params = uriInfo.getQueryParameters();
+        Principal principal = securityContext.getCallerPrincipal();
+
+        //error about redirect_uri && client_id ==> forward user, thus to error.jsp.
+        //otherwise ==> sendRedirect redirect_uri?error=error&error_description=error_description
+        //1. client_id
+        String clientId = params.getFirst("client_id");
+        if (clientId == null || clientId.isEmpty()) {
+            return informUserAboutError(request, response, "Invalid client_id :" + clientId);
+        }
+        Client client = appDataRepository.getClient(clientId);
+        if (client == null) {
+            return informUserAboutError(request, response, "Invalid client_id :" + clientId);
+        }
+        //2. Client Authorized Grant Type
+        String clientError = "";
+        if (client.getAuthorizedGrantTypes() != null && !client.getAuthorizedGrantTypes().contains("authorization_code")) {
+            return informUserAboutError(request, response, "Authorization Grant type, authorization_code, is not allowed for this client :" + clientId);
+        }
+
+        //3. redirectUri
+        String redirectUri = params.getFirst("redirect_uri");
+        if (client.getRedirectUri() != null && !client.getRedirectUri().isEmpty()) {
+            if (redirectUri != null && !redirectUri.isEmpty() && !client.getRedirectUri().equals(redirectUri)) {
+                //sould be in the client.redirectUri
+                return informUserAboutError(request, response, "redirect_uri is pre-registred and should match");
+            }
+            redirectUri = client.getRedirectUri();
+            params.putSingle("resolved_redirect_uri", redirectUri);
+        } else {
+            if (redirectUri == null || redirectUri.isEmpty()) {
+                return informUserAboutError(request, response, "redirect_uri is not pre-registred and should be provided");
+            }
+            params.putSingle("resolved_redirect_uri", redirectUri);
+        }
+        request.setAttribute("client", client);
+
+        //4. response_type
+        String responseType = params.getFirst("response_type");
+        if (!"code".equals(responseType) && !"token".equals(responseType)) {
+            //error = "invalid_grant :" + responseType + ", response_type params should be code or token:";
+            //return informUserAboutError(error);
+        }
+
+        //Save params in session
+        request.getSession().setAttribute("ORIGINAL_PARAMS", params);
+
+        //4.scope: Optional
+        String requestedScope = request.getParameter("scope");
+        if (requestedScope == null || requestedScope.isEmpty()) {
+            requestedScope = client.getScope();
+        }
+        User user = appDataRepository.getUser(principal.getName());
+        String allowedScopes = checkUserScopes(user.getScopes(), requestedScope);
+        request.setAttribute("scopes", allowedScopes);
+
+        request.getRequestDispatcher("/authorize.jsp").forward(request, response);
+        return null;
+    }
+
+    @POST
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    @Produces(MediaType.TEXT_HTML)
+    public Response doPost(@Context HttpServletRequest request,
+                           @Context HttpServletResponse response,
+                           MultivaluedMap<String, String> params) throws Exception {
+        MultivaluedMap<String, String> originalParams = (MultivaluedMap<String, String>) request.getSession().getAttribute("ORIGINAL_PARAMS");
+        if (originalParams == null) {
+            return informUserAboutError(request, response, "No pending authorization request.");
+        }
+        String redirectUri = originalParams.getFirst("resolved_redirect_uri");
+        StringBuilder sb = new StringBuilder(redirectUri);
+
+        String approbationStatus = params.getFirst("approbation_status");
+        if ("NO".equals(approbationStatus)) {
+            URI location = UriBuilder.fromUri(sb.toString())
+                    .queryParam("error", "User doesn't approved the request.")
+                    .queryParam("error_description", "User doesn't approved the request.")
+                    .build();
+            return Response.seeOther(location).build();
+        }
+        //==> YES
+        List<String> approvedScopes = params.get("scope");
+        if (approvedScopes == null || approvedScopes.isEmpty()) {
+            URI location = UriBuilder.fromUri(sb.toString())
+                    .queryParam("error", "User doesn't approved the request.")
+                    .queryParam("error_description", "User doesn't approved the request.")
+                    .build();
+            return Response.seeOther(location).build();
+        }
+
+        String responseType = originalParams.getFirst("response_type");
+        String clientId = originalParams.getFirst("client_id");
+        if ("code".equals(responseType)) {
+            String userId = securityContext.getCallerPrincipal().getName();
+            AuthorizationCode authorizationCode = new AuthorizationCode();
+            authorizationCode.setClientId(clientId);
+            authorizationCode.setUserId(userId);
+            authorizationCode.setApprovedScopes(String.join(" ", approvedScopes));
+            authorizationCode.setExpirationDate(LocalDateTime.now().plusMinutes(10));
+            authorizationCode.setRedirectUri(redirectUri);
+            appDataRepository.save(authorizationCode);
+            String code = authorizationCode.getCode();
+            sb.append("?code=").append(code);
+        } else {
+            //Implicit: responseType=token
+            AuthorizationGrantTypeHandler authorizationGrantTypeHandler = authorizationGrantTypeHandlers.select(NamedLiteral.of("implicit")).get();
+            JsonObject tokenResponse = authorizationGrantTypeHandler.createAccessToken(clientId, params);
+            sb.append("#access_token=").append(tokenResponse.getString("access_token"))
+                    .append("&token_type=").append(tokenResponse.getString("token_type"))
+                    .append("&scope=").append(tokenResponse.getString("scope"));
+        }
+        String state = originalParams.getFirst("state");
+        if (state != null) {
+            sb.append("&state=").append(state);
+        }
+        return Response.seeOther(UriBuilder.fromUri(sb.toString()).build()).build();
+    }
+
+    private String checkUserScopes(String userScopes, String requestedScope) {
+        Set<String> allowedScopes = new LinkedHashSet<>();
+        Set<String> rScopes = new HashSet(Arrays.asList(requestedScope.split(" ")));
+        Set<String> uScopes = new HashSet(Arrays.asList(userScopes.split(" ")));
+        for (String scope : uScopes) {
+            if (rScopes.contains(scope)) allowedScopes.add(scope);
+        }
+        return String.join(" ", allowedScopes);
+    }
+
+    private Response informUserAboutError(HttpServletRequest request, HttpServletResponse response, String error) throws ServletException, IOException {
+        request.setAttribute("error", error);
+        request.getRequestDispatcher("/error.jsp").forward(request, response);
+        return null;
+    }
+}

oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/api/JWKEndpoint.java

@@ -0,0 +1,38 @@
+package com.baeldung.oauth2.authorization.server.api;
+
+import com.baeldung.oauth2.authorization.server.PEMKeyUtils;
+import com.nimbusds.jose.jwk.JWK;
+import org.eclipse.microprofile.config.Config;
+
+import javax.enterprise.context.ApplicationScoped;
+import javax.inject.Inject;
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+import java.util.Arrays;
+
+@Path("jwk")
+@ApplicationScoped
+public class JWKEndpoint {
+
+    @Inject
+    private Config config;
+
+    @GET
+    public Response getKey(@QueryParam("format") String format) throws Exception {
+        if (format != null && !Arrays.asList("jwk", "pem").contains(format)) {
+            return Response.status(Response.Status.BAD_REQUEST).entity("Public Key Format should be : jwk or pem").build();
+        }
+        String verificationkey = config.getValue("verificationkey", String.class);
+        String pemEncodedRSAPublicKey = PEMKeyUtils.readKeyAsString(verificationkey);
+        if (format == null || format.equals("jwk")) {
+            JWK jwk = JWK.parseFromPEMEncodedObjects(pemEncodedRSAPublicKey);
+            return Response.ok(jwk.toJSONString()).type(MediaType.APPLICATION_JSON).build();
+        } else if (format.equals("pem")) {
+            return Response.ok(pemEncodedRSAPublicKey).build();
+        }
+        return null;
+    }
+}

oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/api/TokenEndpoint.java

@@ -0,0 +1,86 @@
+package com.baeldung.oauth2.authorization.server.api;
+
+import com.baeldung.oauth2.authorization.server.handler.AuthorizationGrantTypeHandler;
+import com.baeldung.oauth2.authorization.server.model.AppDataRepository;
+import com.baeldung.oauth2.authorization.server.model.Client;
+import com.nimbusds.jose.JOSEException;
+
+import javax.enterprise.inject.Instance;
+import javax.enterprise.inject.literal.NamedLiteral;
+import javax.inject.Inject;
+import javax.json.Json;
+import javax.json.JsonObject;
+import javax.ws.rs.*;
+import javax.ws.rs.core.HttpHeaders;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.MultivaluedMap;
+import javax.ws.rs.core.Response;
+import java.util.Base64;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+
+@Path("token")
+public class TokenEndpoint {
+
+    List<String> supportedGrantTypes = Collections.singletonList("authorization_code");
+
+    @Inject
+    private AppDataRepository appDataRepository;
+
+    @Inject
+    Instance<AuthorizationGrantTypeHandler> authorizationGrantTypeHandlers;
+
+    @POST
+    @Produces(MediaType.APPLICATION_JSON)
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    public Response token(MultivaluedMap<String, String> params,
+                          @HeaderParam(HttpHeaders.AUTHORIZATION) String authHeader) throws JOSEException {
+
+        //Check grant_type params
+        String grantType = params.getFirst("grant_type");
+        Objects.requireNonNull(grantType, "grant_type params is required");
+        if (!supportedGrantTypes.contains(grantType)) {
+            JsonObject error = Json.createObjectBuilder()
+                    .add("error", "unsupported_grant_type")
+                    .add("error_description", "grant type should be one of :" + supportedGrantTypes)
+                    .build();
+            return Response.status(Response.Status.BAD_REQUEST)
+                    .entity(error).build();
+
+        }
+
+        //Client Authentication
+        String[] clientCredentials = extract(authHeader);
+        String clientId = clientCredentials[0];
+        String clientSecret = clientCredentials[1];
+        Client client = appDataRepository.getClient(clientId);
+        if (client == null || clientSecret == null || !clientSecret.equals(client.getClientSecret())) {
+            JsonObject error = Json.createObjectBuilder()
+                    .add("error", "invalid_client")
+                    .build();
+            return Response.status(Response.Status.UNAUTHORIZED)
+                    .entity(error).build();
+        }
+
+        AuthorizationGrantTypeHandler authorizationGrantTypeHandler = authorizationGrantTypeHandlers.select(NamedLiteral.of(grantType)).get();
+        JsonObject tokenResponse = null;
+        try {
+            tokenResponse = authorizationGrantTypeHandler.createAccessToken(clientId, params);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+
+        return Response.ok(tokenResponse)
+                .header("Cache-Control", "no-store")
+                .header("Pragma", "no-cache")
+                .build();
+    }
+
+    private String[] extract(String authHeader) {
+        if (authHeader != null && authHeader.startsWith("Basic ")) {
+            return new String(Base64.getDecoder().decode(authHeader.substring(6))).split(":");
+        }
+        return null;
+    }
+}