Merge remote-tracking branch 'upstream/master' into BAEL-2781-classgraph

.gitignore

@@ -19,6 +19,7 @@
 .idea/
 *.iml
 *.iws
+out/
 
 # Mac
 .DS_Store
@@ -27,6 +28,9 @@
 log/
 target/
 
+# Gradle
+.gradle/
+
 spring-openid/src/main/resources/application.properties
 .recommenders/
 /spring-hibernate4/nbproject/

akka-streams/pom.xml

@@ -14,18 +14,19 @@
     <dependencies>
         <dependency>
             <groupId>com.typesafe.akka</groupId>
-            <artifactId>akka-stream_2.11</artifactId>
+            <artifactId>akka-stream_${scala.version}</artifactId>
             <version>${akkastreams.version}</version>
         </dependency>
         <dependency>
             <groupId>com.typesafe.akka</groupId>
-            <artifactId>akka-stream-testkit_2.11</artifactId>
+            <artifactId>akka-stream-testkit_${scala.version}</artifactId>
             <version>${akkastreams.version}</version>
         </dependency>
     </dependencies>
 
     <properties>
         <akkastreams.version>2.5.2</akkastreams.version>
+        <scala.version>2.11</scala.version>
     </properties>
 
 </project>

algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/reversingtree/TreeNode.java

@@ -1,42 +1,42 @@
-package com.baeldung.algorithms.reversingtree;
-
-public class TreeNode {
-
-    private int value;
-    private TreeNode rightChild;
-    private TreeNode leftChild;
-
-    public int getValue() {
-        return value;
-    }
-
-    public void setValue(int value) {
-        this.value = value;
-    }
-
-    public TreeNode getRightChild() {
-        return rightChild;
-    }
-
-    public void setRightChild(TreeNode rightChild) {
-        this.rightChild = rightChild;
-    }
-
-    public TreeNode getLeftChild() {
-        return leftChild;
-    }
-
-    public void setLeftChild(TreeNode leftChild) {
-        this.leftChild = leftChild;
-    }
-
-    public TreeNode(int value, TreeNode rightChild, TreeNode leftChild) {
-        this.value = value;
-        this.rightChild = rightChild;
-        this.leftChild = leftChild;
-    }
-
-    public TreeNode(int value) {
-        this.value = value;
-    }
-}
+package com.baeldung.algorithms.reversingtree;
+
+public class TreeNode {
+
+    private int value;
+    private TreeNode rightChild;
+    private TreeNode leftChild;
+
+    public int getValue() {
+        return value;
+    }
+
+    public void setValue(int value) {
+        this.value = value;
+    }
+
+    public TreeNode getRightChild() {
+        return rightChild;
+    }
+
+    public void setRightChild(TreeNode rightChild) {
+        this.rightChild = rightChild;
+    }
+
+    public TreeNode getLeftChild() {
+        return leftChild;
+    }
+
+    public void setLeftChild(TreeNode leftChild) {
+        this.leftChild = leftChild;
+    }
+
+    public TreeNode(int value, TreeNode leftChild, TreeNode rightChild) {
+        this.value = value;
+        this.rightChild = rightChild;
+        this.leftChild = leftChild;
+    }
+
+    public TreeNode(int value) {
+        this.value = value;
+    }
+}

algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/reversingtree/TreeReverser.java

@@ -1,68 +1,53 @@
-package com.baeldung.algorithms.reversingtree;
-
-import java.util.LinkedList;
-
-public class TreeReverser {
-
-    public TreeNode createBinaryTree() {
-
-        TreeNode leaf1 = new TreeNode(3);
-        TreeNode leaf2 = new TreeNode(1);
-        TreeNode leaf3 = new TreeNode(9);
-        TreeNode leaf4 = new TreeNode(6);
-
-        TreeNode nodeLeft = new TreeNode(2, leaf1, leaf2);
-        TreeNode nodeRight = new TreeNode(7, leaf3, leaf4);
-
-        TreeNode root = new TreeNode(4, nodeRight, nodeLeft);
-
-        return root;
-    }
-
-    public void reverseRecursive(TreeNode treeNode) {
-        if (treeNode == null) {
-            return;
-        }
-
-        TreeNode temp = treeNode.getLeftChild();
-        treeNode.setLeftChild(treeNode.getRightChild());
-        treeNode.setRightChild(temp);
-
-        reverseRecursive(treeNode.getLeftChild());
-        reverseRecursive(treeNode.getRightChild());
-    }
-
-    public void reverseIterative(TreeNode treeNode) {
-        LinkedList<TreeNode> queue = new LinkedList<TreeNode>();
-
-        if (treeNode != null) {
-            queue.add(treeNode);
-        }
-
-        while (!queue.isEmpty()) {
-
-            TreeNode node = queue.poll();
-            if (node.getLeftChild() != null)
-                queue.add(node.getLeftChild());
-            if (node.getRightChild() != null)
-                queue.add(node.getRightChild());
-
-            TreeNode temp = node.getLeftChild();
-            node.setLeftChild(node.getRightChild());
-            node.setRightChild(temp);
-        }
-    }
-
-    public String toString(TreeNode root) {
-        if (root == null) {
-            return "";
-        }
-
-        StringBuffer buffer = new StringBuffer(String.valueOf(root.getValue())).append(" ");
-
-        buffer.append(toString(root.getLeftChild()));
-        buffer.append(toString(root.getRightChild()));
-
-        return buffer.toString();
-    }
-}
+package com.baeldung.algorithms.reversingtree;
+
+import java.util.LinkedList;
+
+public class TreeReverser {
+
+    public void reverseRecursive(TreeNode treeNode) {
+        if (treeNode == null) {
+            return;
+        }
+
+        TreeNode temp = treeNode.getLeftChild();
+        treeNode.setLeftChild(treeNode.getRightChild());
+        treeNode.setRightChild(temp);
+
+        reverseRecursive(treeNode.getLeftChild());
+        reverseRecursive(treeNode.getRightChild());
+    }
+
+    public void reverseIterative(TreeNode treeNode) {
+        LinkedList<TreeNode> queue = new LinkedList<TreeNode>();
+
+        if (treeNode != null) {
+            queue.add(treeNode);
+        }
+
+        while (!queue.isEmpty()) {
+
+            TreeNode node = queue.poll();
+            if (node.getLeftChild() != null)
+                queue.add(node.getLeftChild());
+            if (node.getRightChild() != null)
+                queue.add(node.getRightChild());
+
+            TreeNode temp = node.getLeftChild();
+            node.setLeftChild(node.getRightChild());
+            node.setRightChild(temp);
+        }
+    }
+
+    public String toString(TreeNode root) {
+        if (root == null) {
+            return "";
+        }
+
+        StringBuffer buffer = new StringBuffer(String.valueOf(root.getValue())).append(" ");
+
+        buffer.append(toString(root.getLeftChild()));
+        buffer.append(toString(root.getRightChild()));
+
+        return buffer.toString();
+    }
+}

algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/reversingtree/TreeReverserUnitTest.java

@@ -1,33 +1,47 @@
-package com.baeldung.algorithms.reversingtree;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-import org.junit.jupiter.api.Test;
-
-public class TreeReverserUnitTest {
-
-    @Test
-    public void givenTreeWhenReversingRecursivelyThenReversed() {
-        TreeReverser reverser = new TreeReverser();
-
-        TreeNode treeNode = reverser.createBinaryTree();
-
-        reverser.reverseRecursive(treeNode);
-
-        assertEquals("4 7 9 6 2 3 1", reverser.toString(treeNode)
-            .trim());
-    }
-
-    @Test
-    public void givenTreeWhenReversingIterativelyThenReversed() {
-        TreeReverser reverser = new TreeReverser();
-
-        TreeNode treeNode = reverser.createBinaryTree();
-
-        reverser.reverseIterative(treeNode);
-
-        assertEquals("4 7 9 6 2 3 1", reverser.toString(treeNode)
-            .trim());
-    }
-
-}
+package com.baeldung.algorithms.reversingtree;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class TreeReverserUnitTest {
+
+    @Test
+    public void givenTreeWhenReversingRecursivelyThenReversed() {
+        TreeReverser reverser = new TreeReverser();
+
+        TreeNode treeNode = createBinaryTree();
+
+        reverser.reverseRecursive(treeNode);
+
+        assertEquals("4 7 9 6 2 3 1", reverser.toString(treeNode)
+            .trim());
+    }
+
+    @Test
+    public void givenTreeWhenReversingIterativelyThenReversed() {
+        TreeReverser reverser = new TreeReverser();
+
+        TreeNode treeNode = createBinaryTree();
+
+        reverser.reverseIterative(treeNode);
+
+        assertEquals("4 7 9 6 2 3 1", reverser.toString(treeNode)
+            .trim());
+    }
+
+    private TreeNode createBinaryTree() {
+
+        TreeNode leaf1 = new TreeNode(1);
+        TreeNode leaf2 = new TreeNode(3);
+        TreeNode leaf3 = new TreeNode(6);
+        TreeNode leaf4 = new TreeNode(9);
+
+        TreeNode nodeRight = new TreeNode(7, leaf3, leaf4);
+        TreeNode nodeLeft = new TreeNode(2, leaf1, leaf2);
+
+        TreeNode root = new TreeNode(4, nodeLeft, nodeRight);
+
+        return root;
+    }
+}

antlr/pom.xml

@@ -10,6 +10,14 @@
         <version>1.0.0-SNAPSHOT</version>
     </parent>
 
+    <dependencies>
+        <dependency>
+            <groupId>org.antlr</groupId>
+            <artifactId>antlr4-runtime</artifactId>
+            <version>${antlr.version}</version>
+        </dependency>
+    </dependencies>
+
     <build>
         <plugins>
             <plugin>
@@ -44,13 +52,7 @@
             </plugin>
         </plugins>
     </build>
-    <dependencies>
-        <dependency>
-            <groupId>org.antlr</groupId>
-            <artifactId>antlr4-runtime</artifactId>
-            <version>${antlr.version}</version>
-        </dependency>
-    </dependencies>
+    	
     <properties>
         <antlr.version>4.7.1</antlr.version>
         <mojo.version>3.0.0</mojo.version>

apache-cxf/sse-jaxrs/sse-jaxrs-client/pom.xml

@@ -12,9 +12,18 @@
         <version>0.0.1-SNAPSHOT</version>
     </parent>
 
-    <properties>
-        <cxf-version>3.2.0</cxf-version>
-    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.cxf</groupId>
+            <artifactId>cxf-rt-rs-client</artifactId>
+            <version>${cxf-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.cxf</groupId>
+            <artifactId>cxf-rt-rs-sse</artifactId>
+            <version>${cxf-version}</version>
+        </dependency>
+    </dependencies>
 
     <build>
         <plugins>
@@ -45,17 +54,8 @@
         </plugins>
     </build>
 
-    <dependencies>
-        <dependency>
-            <groupId>org.apache.cxf</groupId>
-            <artifactId>cxf-rt-rs-client</artifactId>
-            <version>${cxf-version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.cxf</groupId>
-            <artifactId>cxf-rt-rs-sse</artifactId>
-            <version>${cxf-version}</version>
-        </dependency>
-    </dependencies>
+    <properties>
+        <cxf-version>3.2.0</cxf-version>
+    </properties>
 
 </project>

apache-cxf/sse-jaxrs/sse-jaxrs-server/pom.xml

@@ -13,11 +13,28 @@
         <version>0.0.1-SNAPSHOT</version>
     </parent>
 
-    <properties>
-        <liberty-maven-plugin.version>2.4.2</liberty-maven-plugin.version>
-        <failOnMissingWebXml>false</failOnMissingWebXml>
-        <openliberty-version>18.0.0.2</openliberty-version>
-    </properties>
+    <dependencies>
+
+        <dependency>
+            <groupId>javax.ws.rs</groupId>
+            <artifactId>javax.ws.rs-api</artifactId>
+            <version>2.1</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>javax.enterprise</groupId>
+            <artifactId>cdi-api</artifactId>
+            <version>2.0</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>javax.json.bind</groupId>
+            <artifactId>javax.json.bind-api</artifactId>
+            <version>1.0</version>
+            <scope>provided</scope>
+        </dependency>
+
+    </dependencies>
 
     <build>
         <finalName>${project.artifactId}</finalName>
@@ -59,27 +76,10 @@
         </plugins>
     </build>
 
-    <dependencies>
-
-        <dependency>
-            <groupId>javax.ws.rs</groupId>
-            <artifactId>javax.ws.rs-api</artifactId>
-            <version>2.1</version>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>javax.enterprise</groupId>
-            <artifactId>cdi-api</artifactId>
-            <version>2.0</version>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>javax.json.bind</groupId>
-            <artifactId>javax.json.bind-api</artifactId>
-            <version>1.0</version>
-            <scope>provided</scope>
-        </dependency>
-
-    </dependencies>
+    <properties>
+        <liberty-maven-plugin.version>2.4.2</liberty-maven-plugin.version>
+        <failOnMissingWebXml>false</failOnMissingWebXml>
+        <openliberty-version>18.0.0.2</openliberty-version>
+    </properties>
 
 </project>

apache-meecrowave/pom.xml

@@ -6,6 +6,12 @@
     <version>0.0.1</version>
     <name>apache-meecrowave</name>
     <description>A sample REST API application with Meecrowave</description>
+    
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
 
     <dependencies>
         <!-- https://mvnrepository.com/artifact/org.apache.meecrowave/meecrowave-core -->

apache-meecrowave/src/test/java/com/baeldung/meecrowave/ArticleEndpointsUnitTest.java

@@ -17,7 +17,7 @@ import okhttp3.Request;
 import okhttp3.Response;
 
 @RunWith(MonoMeecrowave.Runner.class)
-public class ArticleEndpointsTest {
+public class ArticleEndpointsUnitTest {
     
     @ConfigurationInject
     private Meecrowave.Builder config;

azure/README.md

@@ -1,4 +1,4 @@
 ### Relevant Articles:
 
-- [Deploy Spring Boot App to Azure](http://www.baeldung.com/spring-boot-azure)
+- [Deploy a Spring Boot App to Azure](http://www.baeldung.com/spring-boot-azure)
 

blade/README.md

@@ -1,5 +1,5 @@
 ### Relevant Articles: 
 
-- [Blade - A Complete GuideBook](http://www.baeldung.com/blade) 
+- [Blade – A Complete Guidebook](http://www.baeldung.com/blade) 
 
-Run Integration Tests with `mvn integration-test`
+Run Integration Tests with `mvn integration-test`

cloud-foundry-uaa/README.md

@@ -0,0 +1,3 @@
+### Revelant Articles
+
+- [A Quick Guide To Using Cloud Foundry UAA](https://www.baeldung.com/cloud-foundry-uaa)

cloud-foundry-uaa/cf-uaa-oauth2-client/pom.xml

@@ -2,24 +2,20 @@
 <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>
-    <parent>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.1.3.RELEASE</version>
-        <relativePath/> <!-- lookup parent from repository -->
-    </parent>
     <groupId>com.example</groupId>
     <artifactId>cf-uaa-oauth2-client</artifactId>
     <version>0.0.1-SNAPSHOT</version>
     <name>uaa-client-webapp</name>
     <description>Demo project for Spring Boot</description>
 
-    <properties>
-        <java.version>1.8</java.version>
-    </properties>
+    <parent>
+        <artifactId>parent-boot-2</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-2</relativePath>
+    </parent>
 
     <dependencies>
-
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
@@ -28,7 +24,6 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-oauth2-client</artifactId>
         </dependency>
-
     </dependencies>
 
     <build>
@@ -40,4 +35,7 @@
         </plugins>
     </build>
 
+    <properties>
+        <java.version>1.8</java.version>
+    </properties>
 </project>

cloud-foundry-uaa/cf-uaa-oauth2-resource-server/pom.xml

@@ -2,24 +2,20 @@
 <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>
-    <parent>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.1.3.RELEASE</version>
-        <relativePath/> <!-- lookup parent from repository -->
-    </parent>
     <groupId>com.baeldung.cfuaa</groupId>
     <artifactId>cf-uaa-oauth2-resource-server</artifactId>
     <version>0.0.1-SNAPSHOT</version>
     <name>cf-uaa-oauth2-resource-server</name>
     <description>Demo project for Spring Boot</description>
 
-    <properties>
-        <java.version>1.8</java.version>
-    </properties>
-
+    <parent>
+        <artifactId>parent-boot-2</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-2</relativePath>
+    </parent>
+	
     <dependencies>
-
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-oauth2-resource-server</artifactId>
@@ -28,7 +24,6 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
-
     </dependencies>
 
     <build>
@@ -40,4 +35,8 @@
         </plugins>
     </build>
 
+    <properties>
+        <java.version>1.8</java.version>
+    </properties>
+
 </project>

core-groovy-2/README.md

@@ -0,0 +1,7 @@
+# Groovy
+
+## Relevant articles:
+
+- [String Matching in Groovy](http://www.baeldung.com/)
+- [Groovy def Keyword]
+

core-groovy-2/pom.xml

@@ -0,0 +1,131 @@
+<?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>
+    <artifactId>core-groovy-2</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <name>core-groovy-2</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.codehaus.groovy</groupId>
+            <artifactId>groovy</artifactId>
+            <version>${groovy.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.codehaus.groovy</groupId>
+            <artifactId>groovy-all</artifactId>
+            <version>${groovy-all.version}</version>
+            <type>pom</type>
+        </dependency>
+        <dependency>
+            <groupId>org.codehaus.groovy</groupId>
+            <artifactId>groovy-dateutil</artifactId>
+            <version>${groovy.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.codehaus.groovy</groupId>
+            <artifactId>groovy-sql</artifactId>
+            <version>${groovy-sql.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit.platform.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.hsqldb</groupId>
+            <artifactId>hsqldb</artifactId>
+            <version>${hsqldb.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.spockframework</groupId>
+            <artifactId>spock-core</artifactId>
+            <version>${spock-core.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.gmavenplus</groupId>
+                <artifactId>gmavenplus-plugin</artifactId>
+                <version>${gmavenplus-plugin.version}</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>addSources</goal>
+                            <goal>addTestSources</goal>
+                            <goal>compile</goal>
+                            <goal>compileTests</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <artifactId>maven-failsafe-plugin</artifactId>
+                <version>${maven-failsafe-plugin.version}</version>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.junit.platform</groupId>
+                        <artifactId>junit-platform-surefire-provider</artifactId>
+                        <version>${junit.platform.version}</version>
+                    </dependency>
+                </dependencies>
+                <executions>
+                    <execution>
+                        <id>junit5</id>
+                        <goals>
+                            <goal>integration-test</goal>
+                            <goal>verify</goal>
+                        </goals>
+                        <configuration>
+                            <includes>
+                                <include>**/*Test5.java</include>
+                            </includes>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>2.20.1</version>
+                <configuration>
+                <useFile>false</useFile>
+                <includes>
+                    <include>**/*Test.java</include>
+                    <include>**/*Spec.java</include>
+                </includes>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <repositories>
+        <repository>
+            <id>central</id>
+            <url>http://jcenter.bintray.com</url>
+        </repository>
+    </repositories>
+
+    <properties>
+        <junit.platform.version>1.0.0</junit.platform.version>
+        <groovy.version>2.5.6</groovy.version>
+        <groovy-all.version>2.5.6</groovy-all.version>
+        <groovy-sql.version>2.5.6</groovy-sql.version>
+        <hsqldb.version>2.4.0</hsqldb.version>
+        <spock-core.version>1.1-groovy-2.4</spock-core.version>
+        <gmavenplus-plugin.version>1.6</gmavenplus-plugin.version>
+    </properties>
+</project>
+

core-groovy-2/src/test/groovy/com/baeldung/defkeyword/DefUnitTest.groovy

@@ -0,0 +1,79 @@
+package com.baeldung.defkeyword
+
+import org.codehaus.groovy.runtime.NullObject
+import org.codehaus.groovy.runtime.typehandling.GroovyCastException
+
+import groovy.transform.TypeChecked
+import groovy.transform.TypeCheckingMode
+
+@TypeChecked
+class DefUnitTest extends GroovyTestCase {
+    
+    def id
+    def firstName = "Samwell"
+    def listOfCountries = ['USA', 'UK', 'FRANCE', 'INDIA']
+    
+    @TypeChecked(TypeCheckingMode.SKIP)
+    def multiply(x, y) {
+        return x*y
+    }
+        
+    @TypeChecked(TypeCheckingMode.SKIP)
+    void testDefVariableDeclaration() {
+        
+        def list
+        assert list.getClass() == org.codehaus.groovy.runtime.NullObject
+        assert list.is(null)
+        
+        list = [1,2,4]
+        assert list instanceof ArrayList
+    }
+    
+    @TypeChecked(TypeCheckingMode.SKIP)
+    void testTypeVariables() {   
+        int rate = 200
+        try {
+            rate = [12] //GroovyCastException
+            rate = "nill" //GroovyCastException
+        } catch(GroovyCastException) {
+            println "Cannot assign anything other than integer"
+        }
+    }
+     
+    @TypeChecked(TypeCheckingMode.SKIP)
+    void testDefVariableMultipleAssignment() {
+        def rate
+        assert rate == null
+        assert rate.getClass() == org.codehaus.groovy.runtime.NullObject
+        
+        rate = 12
+        assert rate instanceof Integer
+        
+        rate = "Not Available"
+        assert rate instanceof String
+        
+        rate = [1, 4]
+        assert rate instanceof List
+        
+        assert divide(12, 3) instanceof BigDecimal
+        assert divide(1, 0) instanceof String
+
+    }
+    
+    def divide(int x, int y) {
+        if(y==0) {
+            return "Should not divide by 0"
+        } else {
+            return x/y
+        }
+    }
+    
+    def greetMsg() {
+        println "Hello! I am Groovy"
+    }
+    
+    void testDefVsType() {
+        def int count
+        assert count instanceof Integer
+    }
+}

core-groovy-2/src/test/groovy/com/baeldung/strings/StringMatchingSpec.groovy

@@ -0,0 +1,44 @@
+package com.baeldung.strings
+
+import spock.lang.Specification
+
+import java.util.regex.Pattern
+
+class StringMatchingSpec extends Specification {
+
+    def "pattern operator example"() {
+        given: "a pattern"
+        def p = ~'foo'
+
+        expect:
+        p instanceof Pattern
+
+        and: "you can use slash strings to avoid escaping of blackslash"
+        def digitPattern = ~/\d*/
+        digitPattern.matcher('4711').matches()
+    }
+
+    def "match operator example"() {
+        expect:
+        'foobar' ==~ /.*oba.*/
+
+        and: "matching is strict"
+        !('foobar' ==~ /foo/)
+    }
+
+    def "find operator example"() {
+        when: "using the find operator"
+        def matcher = 'foo and bar, baz and buz' =~ /(\w+) and (\w+)/
+
+        then: "will find groups"
+        matcher.size() == 2
+
+        and: "can access groups using array"
+        matcher[0][0] == 'foo and bar'
+        matcher[1][2] == 'buz'
+
+        and: "you can use it as a predicate"
+        'foobarbaz' =~ /bar/
+    }
+
+}

core-groovy/README.md

@@ -8,6 +8,8 @@
 - [Types of Strings in Groovy](https://www.baeldung.com/groovy-strings)
 - [A Quick Guide to Iterating a Map in Groovy](https://www.baeldung.com/groovy-map-iterating)
 - [An Introduction to Traits in Groovy](https://www.baeldung.com/groovy-traits)
+- [Closures in Groovy](https://www.baeldung.com/groovy-closures)
+- [Finding Elements in Collections in Groovy](https://www.baeldung.com/groovy-collections-find-elements)
 - [Lists in Groovy](https://www.baeldung.com/groovy-lists)
 - [Converting a String to a Date in Groovy](https://www.baeldung.com/groovy-string-to-date)
-- [Guide to I/O in Groovy](https://www.baeldung.com/groovy-io)
+- [Guide to I/O in Groovy](https://www.baeldung.com/groovy-io)

core-groovy/src/test/groovy/com/baeldung/strings/StringMatchingSpec.groovy

@@ -0,0 +1,44 @@
+package com.baeldung.strings
+
+import spock.lang.Specification
+
+import java.util.regex.Pattern
+
+class StringMatchingSpec extends Specification {
+
+    def "pattern operator example"() {
+        given: "a pattern"
+        def p = ~'foo'
+
+        expect:
+        p instanceof Pattern
+
+        and: "you can use slash strings to avoid escaping of blackslash"
+        def digitPattern = ~/\d*/
+        digitPattern.matcher('4711').matches()
+    }
+
+    def "match operator example"() {
+        expect:
+        'foobar' ==~ /.*oba.*/
+
+        and: "matching is strict"
+        !('foobar' ==~ /foo/)
+    }
+
+    def "find operator example"() {
+        when: "using the find operator"
+        def matcher = 'foo and bar, baz and buz' =~ /(\w+) and (\w+)/
+
+        then: "will find groups"
+        matcher.size() == 2
+
+        and: "can access groups using array"
+        matcher[0][0] == 'foo and bar'
+        matcher[1][2] == 'buz'
+
+        and: "you can use it as a predicate"
+        'foobarbaz' =~ /bar/
+    }
+
+}

core-java-11/README.md

@@ -6,3 +6,4 @@
 - [Java 11 Nest Based Access Control](https://www.baeldung.com/java-nest-based-access-control)
 - [Exploring the New HTTP Client in Java 9 and 11](https://www.baeldung.com/java-9-http-client)
 - [An Introduction to Epsilon GC: A No-Op Experimental Garbage Collector](https://www.baeldung.com/jvm-epsilon-gc-garbage-collector)
+- [Guide to jlink](https://www.baeldung.com/jlink)

core-java-11/pom.xml

@@ -14,6 +14,14 @@
         <version>1.0.0-SNAPSHOT</version>
     </parent>
 
+    <dependencies>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
+    </dependencies>
+
     <build>
         <plugins>
             <plugin>
@@ -31,6 +39,7 @@
     <properties>
         <maven.compiler.source.version>11</maven.compiler.source.version>
         <maven.compiler.target.version>11</maven.compiler.target.version>
+        <guava.version>27.1-jre</guava.version>
     </properties>
 
 </project>

core-java-11/src/test/java/com/baeldung/EmptyStringToEmptyOptionalUnitTest.java

@@ -0,0 +1,32 @@
+package com.baeldung;
+
+import com.google.common.base.Strings;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Optional;
+import java.util.function.Predicate;
+
+public class EmptyStringToEmptyOptionalUnitTest {
+
+    @Test
+    public void givenEmptyString_whenFilteringOnOptional_thenEmptyOptionalIsReturned() {
+        String str = "";
+        Optional<String> opt = Optional.ofNullable(str).filter(s -> !s.isEmpty());
+        Assert.assertFalse(opt.isPresent());
+    }
+
+    @Test
+    public void givenEmptyString_whenFilteringOnOptionalInJava11_thenEmptyOptionalIsReturned() {
+        String str = "";
+        Optional<String> opt = Optional.ofNullable(str).filter(Predicate.not(String::isEmpty));
+        Assert.assertFalse(opt.isPresent());
+    }
+
+    @Test
+    public void givenEmptyString_whenPassingResultOfEmptyToNullToOfNullable_thenEmptyOptionalIsReturned() {
+        String str = "";
+        Optional<String> opt = Optional.ofNullable(Strings.emptyToNull(str));
+        Assert.assertFalse(opt.isPresent());
+    }
+}

core-java-12/pom.xml

@@ -34,6 +34,7 @@
                 <configuration>
                     <source>${maven.compiler.source.version}</source>
                     <target>${maven.compiler.target.version}</target>
+                    <compilerArgs>--enable-preview</compilerArgs>
                 </configuration>
             </plugin>
         </plugins>

core-java-12/src/test/java/com/baeldung/switchExpression/SwitchUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.switchExpression;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class SwitchUnitTest {
+
+    @Test
+    public void switchJava12(){
+
+        var month = Month.AUG;
+
+        var value = switch(month){
+            case JAN,JUN, JUL -> 3;
+            case FEB,SEP, OCT, NOV, DEC -> 1;
+            case MAR,MAY, APR, AUG -> 2;
+        };
+
+        Assert.assertEquals(value, 2);
+    }
+
+    @Test
+    public void switchLocalVariable(){
+        var month = Month.AUG;
+        int i = switch (month){
+            case JAN,JUN, JUL -> 3;
+            case FEB,SEP, OCT, NOV, DEC -> 1;
+            case MAR,MAY, APR, AUG -> {
+                int j = month.toString().length() * 4;
+                break j;
+            }
+        };
+        Assert.assertEquals(12, i);
+    }
+
+    enum Month {JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC}
+}

core-java-8-2/README.md

@@ -0,0 +1,6 @@
+=========
+
+## Core Java 8 Cookbooks and Examples (part 2)
+
+### Relevant Articles: 
+- [Anonymous Classes in Java](http://www.baeldung.com/)

core-java-8-2/pom.xml

@@ -0,0 +1,43 @@
+<?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</groupId>
+    <artifactId>core-java-8-2</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-8-2</name>
+    <packaging>jar</packaging>
+
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-java</relativePath>
+    </parent>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${maven.compiler.source}</source>
+                    <target>${maven.compiler.target}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+
+    </build>
+</project>

core-java-8/README.md

@@ -3,7 +3,7 @@
 ## Core Java 8 Cookbooks and Examples
 
 ### Relevant Articles: 
-- [Java 8 Collectors](http://www.baeldung.com/java-8-collectors)
+- [Guide to Java 8’s Collectors](http://www.baeldung.com/java-8-collectors)
 - [Functional Interfaces in Java 8](http://www.baeldung.com/java-8-functional-interfaces)
 - [Java 8 – Powerful Comparison with Lambdas](http://www.baeldung.com/java-8-sort-lambda)
 - [New Features in Java 8](http://www.baeldung.com/java-8-new-features)

core-java-8/src/main/java/com/baeldung/Adder.java

@@ -1,12 +0,0 @@
-package com.baeldung;
-
-import java.util.function.Consumer;
-import java.util.function.Function;
-
-public interface Adder {
-
-    String addWithFunction(Function<String, String> f);
-
-    void addWithConsumer(Consumer<Integer> f);
-
-}

core-java-8/src/main/java/com/baeldung/AdderImpl.java

@@ -1,18 +0,0 @@
-package com.baeldung;
-
-
-import java.util.function.Consumer;
-import java.util.function.Function;
-
-public class AdderImpl implements Adder {
-
-    @Override
-    public String addWithFunction(final Function<String, String> f) {
-        return f.apply("Something ");
-    }
-
-    @Override
-    public void addWithConsumer(final Consumer<Integer> f) {
-    }
-
-}

core-java-8/src/main/java/com/baeldung/java8/lambda/tips/Bar.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.java8.lambda.tips;
 
 
 @FunctionalInterface

core-java-8/src/main/java/com/baeldung/java8/lambda/tips/Baz.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.java8.lambda.tips;
 
 
 @FunctionalInterface

core-java-8/src/main/java/com/baeldung/java8/lambda/tips/Foo.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.java8.lambda.tips;
 
 
 @FunctionalInterface

core-java-8/src/main/java/com/baeldung/java8/lambda/tips/FooExtended.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.java8.lambda.tips;
 
 
 @FunctionalInterface

core-java-8/src/main/java/com/baeldung/java8/lambda/tips/Processor.java

@@ -0,0 +1,12 @@
+package com.baeldung.java8.lambda.tips;
+
+import java.util.concurrent.Callable;
+import java.util.function.Supplier;
+
+public interface Processor {
+
+    String processWithCallable(Callable<String> c) throws Exception;
+
+    String processWithSupplier(Supplier<String> s);
+
+}

core-java-8/src/main/java/com/baeldung/java8/lambda/tips/ProcessorImpl.java

@@ -0,0 +1,20 @@
+package com.baeldung.java8.lambda.tips;
+
+
+import java.util.concurrent.Callable;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+public class ProcessorImpl implements Processor {
+
+    @Override
+    public String processWithCallable(Callable<String> c) throws Exception {
+        return c.call();
+    }
+
+    @Override
+    public String processWithSupplier(Supplier<String> s) {
+        return s.get();
+    }
+}

core-java-8/src/main/java/com/baeldung/java8/lambda/tips/UseFoo.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.java8.lambda.tips;
 
 
 import java.util.function.Function;

core-java-8/src/test/java/com/baeldung/java8/lambda/tips/Java8FunctionalInteracesLambdasUnitTest.java

@@ -1,8 +1,8 @@
-package com.baeldung.java8;
+package com.baeldung.java8.lambda.tips;
 
-import com.baeldung.Foo;
-import com.baeldung.FooExtended;
-import com.baeldung.UseFoo;
+import com.baeldung.java8.lambda.tips.Foo;
+import com.baeldung.java8.lambda.tips.FooExtended;
+import com.baeldung.java8.lambda.tips.UseFoo;
 import org.junit.Before;
 import org.junit.Test;
 

core-java-8/src/test/java/com/baeldung/reduceIfelse/CalculatorUnitTest.java

@@ -29,4 +29,11 @@ public class CalculatorUnitTest {
         int result = calculator.calculate(new AddCommand(3, 7));
         assertEquals(10, result);
     }
+
+    @Test
+    public void whenCalculateUsingFactory_thenReturnCorrectResult() {
+        Calculator calculator = new Calculator();
+        int result = calculator.calculateUsingFactory(3, 4, "add");
+        assertEquals(7, result);
+    }
 }

core-java-9/README.md

@@ -5,26 +5,21 @@
 [Java 9 New Features](http://www.baeldung.com/new-java-9)
 
 ### Relevant Articles:
-- [Java 9 Stream API Improvements](http://www.baeldung.com/java-9-stream-api)
-- [Java 9 Convenience Factory Methods for Collections](http://www.baeldung.com/java-9-collections-factory-methods) 
+
+- [Java 9 New Features](https://www.baeldung.com/new-java-9)
 - [New Stream Collectors in Java 9](http://www.baeldung.com/java9-stream-collectors)
-- [Java 9 CompletableFuture API Improvements](http://www.baeldung.com/java-9-completablefuture)
-- [Introduction to Java 9 StackWalking API](http://www.baeldung.com/java-9-stackwalking-api)
 - [Introduction to Project Jigsaw](http://www.baeldung.com/project-jigsaw-java-modularity)
-- [Java 9 Optional API Additions](http://www.baeldung.com/java-9-optional)
-- [Java 9 Reactive Streams](http://www.baeldung.com/java-9-reactive-streams)
-- [Java 9 java.util.Objects Additions](http://www.baeldung.com/java-9-objects-new)
-- [Java 9 Variable Handles Demistyfied](http://www.baeldung.com/java-variable-handles)
+- [Java 9 Variable Handles Demystified](http://www.baeldung.com/java-variable-handles)
 - [Exploring the New HTTP Client in Java 9 and 11](http://www.baeldung.com/java-9-http-client)
 - [Method Handles in Java](http://www.baeldung.com/java-method-handles)
 - [Introduction to Chronicle Queue](http://www.baeldung.com/java-chronicle-queue)
-- [A Guide to Java 9 Modularity](http://www.baeldung.com/java-9-modularity)
 - [Optional orElse Optional](http://www.baeldung.com/java-optional-or-else-optional)
-- [Java 9 java.lang.Module API](http://www.baeldung.com/java-9-module-api)
 - [Iterate Through a Range of Dates in Java](https://www.baeldung.com/java-iterate-date-range)
 - [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)
-- [Java 9 Platform Logging API](https://www.baeldung.com/java-9-logging-api)
 - [Immutable Set in Java](https://www.baeldung.com/java-immutable-set)
 - [Multi-Release Jar Files](https://www.baeldung.com/java-multi-release-jar)
 - [Ahead of Time Compilation (AoT)](https://www.baeldung.com/ahead-of-time-compilation)
+- [Java 9 Process API Improvements](https://www.baeldung.com/java-9-process-api)
+- [Guide to java.lang.Process API](https://www.baeldung.com/java-process-api)
+
 

core-java-collections-map/README.md

@@ -0,0 +1,6 @@
+=========
+
+## Core Java Collections 2
+
+### Relevant Articles: 
+- Java - Copying a HashMap

core-java-collections-map/pom.xml

@@ -0,0 +1,78 @@
+<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>core-java-collections-map</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-collections-map</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>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.eclipse.collections</groupId>
+            <artifactId>eclipse-collections</artifactId>
+            <version>${eclipse.collections.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit.platform.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${openjdk.jmh.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${openjdk.jmh.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-exec</artifactId>
+            <version>${commons-exec.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <openjdk.jmh.version>1.19</openjdk.jmh.version>
+        <junit.platform.version>1.2.0</junit.platform.version>
+        <commons-lang3.version>3.8.1</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>
+        <assertj.version>3.11.1</assertj.version>
+        <eclipse.collections.version>7.1.0</eclipse.collections.version>
+		<commons-exec.version>1.3</commons-exec.version>
+    </properties>
+</project>

core-java-collections-map/src/main/java/com/baeldung/copyinghashmap/CopyHashMap.java

@@ -0,0 +1,55 @@
+package com.baeldung.copyinghashmap;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import org.apache.commons.lang3.SerializationUtils;
+
+public class CopyHashMap {
+    
+    public static <String, Employee> HashMap<String, Employee> copyUsingConstructor(HashMap<String, Employee> originalMap) {
+        return new HashMap<String, Employee>(originalMap);
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> copyUsingClone(HashMap<String, Employee> originalMap) {
+        return (HashMap<String, Employee>) originalMap.clone();
+    }
+
+    public static <String, Employee> HashMap<String, Employee> copyUsingPut(HashMap<String, Employee> originalMap) {
+        HashMap<String, Employee> shallowCopy = new HashMap<String, Employee>();
+        Set<Entry<String, Employee>> entries = originalMap.entrySet();
+        for(Map.Entry<String, Employee> mapEntry: entries) {
+            shallowCopy.put(mapEntry.getKey(), mapEntry.getValue());
+        }
+        
+        return shallowCopy;
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> copyUsingPutAll(HashMap<String, Employee> originalMap) {
+        HashMap<String, Employee> shallowCopy = new HashMap<String, Employee>();
+        shallowCopy.putAll(originalMap);
+        
+        return shallowCopy;
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> copyUsingJava8Stream(HashMap<String, Employee> originalMap) {
+        Set<Entry<String, Employee>> entries = originalMap.entrySet();
+        HashMap<String, Employee> shallowCopy = (HashMap<String, Employee>) entries
+            .stream()
+            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+        
+        return shallowCopy;
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> shallowCopy(HashMap<String, Employee> originalMap) {
+        return (HashMap<String, Employee>) originalMap.clone();
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> deepCopy(HashMap<String, Employee> originalMap) {
+        return SerializationUtils.clone(originalMap);
+    }
+    
+}

core-java-collections-map/src/test/java/com/baeldung/copyinghashmap/CopyHashMapUnitTest.java

@@ -0,0 +1,77 @@
+package com.baeldung.copyinghashmap;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Test;
+
+import com.google.common.collect.ImmutableMap;
+
+public class CopyHashMapUnitTest {
+    
+    @Test
+    public void givenHashMap_whenShallowCopy_thenCopyisNotSameAsOriginal() {
+        
+        HashMap<String, Employee> map = new HashMap<>();
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        map.put("emp1",emp1);
+        map.put("emp2",emp2);
+    
+        HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
+        
+        assertThat(shallowCopy).isNotSameAs(map);
+        
+    }
+    
+    @Test
+    public void givenHashMap_whenShallowCopyModifyingOriginalObject_thenCopyShouldChange() {
+        
+        HashMap<String, Employee> map = new HashMap<>();
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        map.put("emp1",emp1);
+        map.put("emp2",emp2);
+        
+        HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
+        
+        emp1.setName("Johny");
+        
+        assertThat(shallowCopy.get("emp1")).isEqualTo(map.get("emp1"));
+        
+    }
+    
+    @Test
+    public void givenHashMap_whenDeepCopyModifyingOriginalObject_thenCopyShouldNotChange() {
+        
+        HashMap<String, Employee> map = new HashMap<>();
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        map.put("emp1",emp1);
+        map.put("emp2",emp2);
+        HashMap<String, Employee> deepCopy = CopyHashMap.deepCopy(map);
+        
+        emp1.setName("Johny");
+        
+        assertThat(deepCopy.get("emp1")).isNotEqualTo(map.get("emp1"));
+        
+    }
+    
+    @Test
+    public void givenImmutableMap_whenCopyUsingGuava_thenCopyShouldNotChange() {
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        
+        Map<String, Employee> map = ImmutableMap.<String, Employee> builder()
+            .put("emp1",emp1)
+            .put("emp2",emp2)
+            .build();
+        Map<String, Employee> shallowCopy = ImmutableMap.copyOf(map);
+        
+        assertThat(shallowCopy).isSameAs(map);
+        
+    }
+
+}

core-java-collections-map/src/test/java/com/baeldung/copyinghashmap/Employee.java

@@ -0,0 +1,28 @@
+package com.baeldung.copyinghashmap;
+
+import java.io.Serializable;
+
+public class Employee implements Serializable{
+    
+    private String name;
+    
+    public Employee(String name) {
+        super();
+        this.name = name;
+    }
+    public String getName() {
+        return name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+    
+    @Override
+    public String toString() {
+        return this.name;
+    }
+ 
+}
+
+

core-java-collections/README.md

@@ -3,7 +3,7 @@
 ## Core Java Collections Cookbooks and Examples
 
 ### Relevant Articles: 
-- [Java - Combine Multiple Collections](http://www.baeldung.com/java-combine-multiple-collections)
+- [Java – Combine Multiple Collections](http://www.baeldung.com/java-combine-multiple-collections)
 - [HashSet and TreeSet Comparison](http://www.baeldung.com/java-hashset-vs-treeset)
 - [Collect a Java Stream to an Immutable Collection](http://www.baeldung.com/java-stream-immutable-collection)
 - [Introduction to the Java ArrayDeque](http://www.baeldung.com/java-array-deque)

core-java-concurrency-advanced/README.md

@@ -12,7 +12,7 @@
 - [Guide to the Java Phaser](http://www.baeldung.com/java-phaser)
 - [An Introduction to Atomic Variables in Java](http://www.baeldung.com/java-atomic-variables)
 - [CyclicBarrier in Java](http://www.baeldung.com/java-cyclic-barrier)
-- [Guide to Volatile Keyword in Java](http://www.baeldung.com/java-volatile)
+- [Guide to the Volatile Keyword in Java](http://www.baeldung.com/java-volatile)
 - [Semaphores in Java](http://www.baeldung.com/java-semaphore)
 - [Daemon Threads in Java](http://www.baeldung.com/java-daemon-thread)
 - [Priority-based Job Scheduling in Java](http://www.baeldung.com/java-priority-job-schedule)
@@ -20,6 +20,6 @@
 - [Print Even and Odd Numbers Using 2 Threads](https://www.baeldung.com/java-even-odd-numbers-with-2-threads)
 - [Java CyclicBarrier vs CountDownLatch](https://www.baeldung.com/java-cyclicbarrier-countdownlatch)
 - [Guide to the Fork/Join Framework in Java](http://www.baeldung.com/java-fork-join)
-- [A Guide to ThreadLocalRandom in Java](http://www.baeldung.com/java-thread-local-random)
+- [Guide to ThreadLocalRandom in Java](http://www.baeldung.com/java-thread-local-random)
 - [The Thread.join() Method in Java](http://www.baeldung.com/java-thread-join)
 - [Passing Parameters to Java Threads](https://www.baeldung.com/java-thread-parameters)

core-java-concurrency-basic/README.md

@@ -7,13 +7,13 @@
 - [A Guide to the Java ExecutorService](http://www.baeldung.com/java-executor-service-tutorial)
 - [Guide to java.util.concurrent.Future](http://www.baeldung.com/java-future)
 - [Difference Between Wait and Sleep in Java](http://www.baeldung.com/java-wait-and-sleep)
-- [Guide to Synchronized Keyword in Java](http://www.baeldung.com/java-synchronized)
+- [Guide to the Synchronized Keyword in Java](http://www.baeldung.com/java-synchronized)
 - [Overview of the java.util.concurrent](http://www.baeldung.com/java-util-concurrent)
 - [Implementing a Runnable vs Extending a Thread](http://www.baeldung.com/java-runnable-vs-extending-thread)
 - [How to Kill a Java Thread](http://www.baeldung.com/java-thread-stop)
-- [ExecutorService - Waiting for Threads to Finish](http://www.baeldung.com/java-executor-wait-for-threads)
+- [ExecutorService – Waiting for Threads to Finish](http://www.baeldung.com/java-executor-wait-for-threads)
 - [wait and notify() Methods in Java](http://www.baeldung.com/java-wait-notify)
 - [Life Cycle of a Thread in Java](http://www.baeldung.com/java-thread-lifecycle)
 - [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)
+- [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)

core-java-io/README.md

@@ -6,7 +6,7 @@
 - [How to Read a Large File Efficiently with Java](http://www.baeldung.com/java-read-lines-large-file)
 - [Java InputStream to String](http://www.baeldung.com/convert-input-stream-to-string)
 - [Java – Write to File](http://www.baeldung.com/java-write-to-file)
-- [Java - Convert File to InputStream](http://www.baeldung.com/convert-file-to-input-stream)
+- [Java – Convert File to InputStream](http://www.baeldung.com/convert-file-to-input-stream)
 - [Java Scanner](http://www.baeldung.com/java-scanner)
 - [Java – Byte Array to Writer](http://www.baeldung.com/java-convert-byte-array-to-writer)
 - [Java – Directory Size](http://www.baeldung.com/java-folder-size)
@@ -14,7 +14,7 @@
 - [File Size in Java](http://www.baeldung.com/java-file-size)
 - [Comparing getPath(), getAbsolutePath(), and getCanonicalPath() in Java](http://www.baeldung.com/java-path)
 - [Using Java MappedByteBuffer](http://www.baeldung.com/java-mapped-byte-buffer)
-- [Copy a File with Java](http://www.baeldung.com/java-copy-file)
+- [How to Copy a File with Java](http://www.baeldung.com/java-copy-file)
 - [Java – Append Data to a File](http://www.baeldung.com/java-append-to-file)
 - [FileNotFoundException in Java](http://www.baeldung.com/java-filenotfound-exception)
 - [How to Read a File in Java](http://www.baeldung.com/reading-file-in-java)

core-java-io/src/test/java/com/baeldung/filechannel/FileChannelUnitTest.java

@@ -0,0 +1,165 @@
+package com.baeldung.filechannel;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.io.ByteArrayOutputStream;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.nio.MappedByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
+import java.nio.charset.StandardCharsets;
+
+import org.junit.Test;
+
+public class FileChannelUnitTest {
+
+    @Test
+    public void givenFile_whenReadWithFileChannelUsingRandomAccessFile_thenCorrect() throws IOException {
+
+        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
+            FileChannel channel = reader.getChannel(); 
+            ByteArrayOutputStream out = new ByteArrayOutputStream();) {
+
+            int bufferSize = 1024;
+            if (bufferSize > channel.size()) {
+                bufferSize = (int) channel.size();
+            }
+            ByteBuffer buff = ByteBuffer.allocate(bufferSize);
+
+            while (channel.read(buff) > 0) {
+                out.write(buff.array(), 0, buff.position());
+                buff.clear();
+            }
+
+            String fileContent = new String(out.toByteArray(), StandardCharsets.UTF_8);
+
+            assertEquals("Hello world", fileContent);
+        }
+    }
+
+    @Test
+    public void givenFile_whenReadWithFileChannelUsingFileInputStream_thenCorrect() throws IOException {
+
+        try (ByteArrayOutputStream out = new ByteArrayOutputStream(); 
+            FileInputStream fin = new FileInputStream("src/test/resources/test_read.in"); 
+            FileChannel channel = fin.getChannel();) {
+
+            int bufferSize = 1024;
+            if (bufferSize > channel.size()) {
+                bufferSize = (int) channel.size();
+            }
+            ByteBuffer buff = ByteBuffer.allocate(bufferSize);
+
+            while (channel.read(buff) > 0) {
+                out.write(buff.array(), 0, buff.position());
+                buff.clear();
+            }
+            String fileContent = new String(out.toByteArray(), StandardCharsets.UTF_8);
+
+            assertEquals("Hello world", fileContent);
+        }
+    }
+
+    @Test
+    public void givenFile_whenReadAFileSectionIntoMemoryWithFileChannel_thenCorrect() throws IOException {
+
+        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
+            FileChannel channel = reader.getChannel(); 
+            ByteArrayOutputStream out = new ByteArrayOutputStream();) {
+
+            MappedByteBuffer buff = channel.map(FileChannel.MapMode.READ_ONLY, 6, 5);
+
+            if (buff.hasRemaining()) {
+                byte[] data = new byte[buff.remaining()];
+                buff.get(data);
+                assertEquals("world", new String(data, StandardCharsets.UTF_8));
+            }
+        }
+    }
+
+    @Test
+    public void whenWriteWithFileChannelUsingRandomAccessFile_thenCorrect() throws IOException {
+        String file = "src/test/resources/test_write_using_filechannel.txt";
+        try (RandomAccessFile writer = new RandomAccessFile(file, "rw"); 
+            FileChannel channel = writer.getChannel();) {
+            ByteBuffer buff = ByteBuffer.wrap("Hello world".getBytes(StandardCharsets.UTF_8));
+
+            channel.write(buff);
+
+            // now we verify whether the file was written correctly
+            RandomAccessFile reader = new RandomAccessFile(file, "r");
+            assertEquals("Hello world", reader.readLine());
+            reader.close();
+        }
+    }
+
+    @Test
+    public void givenFile_whenWriteAFileUsingLockAFileSectionWithFileChannel_thenCorrect() throws IOException {
+        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "rw"); 
+            FileChannel channel = reader.getChannel(); 
+            FileLock fileLock = channel.tryLock(6, 5, Boolean.FALSE);) {
+
+            assertNotNull(fileLock);
+        }
+    }
+
+    @Test
+    public void givenFile_whenReadWithFileChannelGetPosition_thenCorrect() throws IOException {
+
+        try (ByteArrayOutputStream out = new ByteArrayOutputStream(); 
+            RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
+            FileChannel channel = reader.getChannel();) {
+
+            int bufferSize = 1024;
+            if (bufferSize > channel.size()) {
+                bufferSize = (int) channel.size();
+            }
+            ByteBuffer buff = ByteBuffer.allocate(bufferSize);
+
+            while (channel.read(buff) > 0) {
+                out.write(buff.array(), 0, buff.position());
+                buff.clear();
+            }
+
+            // the original file is 11 bytes long, so that's where the position pointer should be
+            assertEquals(11, channel.position());
+
+            channel.position(4);
+            assertEquals(4, channel.position());
+        }
+    }
+
+    @Test
+    public void whenGetFileSize_thenCorrect() throws IOException {
+
+        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
+            FileChannel channel = reader.getChannel();) {
+
+            // the original file is 11 bytes long, so that's where the position pointer should be
+            assertEquals(11, channel.size());
+        }
+    }
+
+    @Test
+    public void whenTruncateFile_thenCorrect() throws IOException {
+        String input = "this is a test input";
+
+        FileOutputStream fout = new FileOutputStream("src/test/resources/test_truncate.txt");
+        FileChannel channel = fout.getChannel();
+
+        ByteBuffer buff = ByteBuffer.wrap(input.getBytes());
+        channel.write(buff);
+        buff.flip();
+
+        channel = channel.truncate(5);
+        assertEquals(5, channel.size());
+
+        fout.close();
+        channel.close();
+    }
+}

core-java-io/src/test/resources/test_truncate.txt

@@ -0,0 +1 @@
+this 

core-java-io/src/test/resources/test_write_using_filechannel.txt

@@ -0,0 +1 @@
+Hello world

core-java-jvm/README.md

@@ -3,4 +3,4 @@
 ## Core Java JVM Cookbooks and Examples
 
 ### Relevant Articles: 
-- [Method Inlining in the JVM](http://www.baeldung.com/method-inlining-in-the-jvm/)
+- [Method Inlining in the JVM](https://www.baeldung.com/jvm-method-inlining)

core-java-lambdas/pom.xml

@@ -0,0 +1,19 @@
+<?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>
+  <artifactId>core-java-lambdas</artifactId>
+  <version>0.1.0-SNAPSHOT</version>
+  <name>core-java</name>
+  <packaging>jar</packaging>
+
+  <parent>
+    <groupId>com.baeldung</groupId>
+    <artifactId>parent-java</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <relativePath>../parent-java</relativePath>
+  </parent>
+
+
+</project>

core-java-lambdas/src/main/java/com/baeldung/lambdas/LambdaVariables.java

@@ -0,0 +1,88 @@
+package com.baeldung.lambdas;
+
+import java.util.Random;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.function.Supplier;
+import java.util.stream.IntStream;
+
+/**
+ * Class with examples about working with capturing lambdas.
+ */
+public class LambdaVariables {
+
+    private volatile boolean run = true;
+    private int start = 0;
+
+    private ExecutorService executor = Executors.newFixedThreadPool(3);
+
+    public static void main(String[] args) {
+        new LambdaVariables().localVariableMultithreading();
+    }
+
+    Supplier<Integer> incrementer(int start) {
+        return () -> start; // can't modify start parameter inside the lambda
+    }
+
+    Supplier<Integer> incrementer() {
+        return () -> start++;
+    }
+
+    public void localVariableMultithreading() {
+        boolean run = true;
+        executor.execute(() -> {
+            while (run) {
+                // do operation
+            }
+        });
+        // commented because it doesn't compile, it's just an example of non-final local variables in lambdas
+        // run = false;
+    }
+
+    public void instanceVariableMultithreading() {
+        executor.execute(() -> {
+            while (run) {
+                // do operation
+            }
+        });
+
+        run = false;
+    }
+
+    /**
+     * WARNING: always avoid this workaround!!
+     */
+    public void workaroundSingleThread() {
+        int[] holder = new int[] { 2 };
+        IntStream sums = IntStream
+          .of(1, 2, 3)
+          .map(val -> val + holder[0]);
+
+        holder[0] = 0;
+
+        System.out.println(sums.sum());
+    }
+
+    /**
+     * WARNING: always avoid this workaround!!
+     */
+    public void workaroundMultithreading() {
+        int[] holder = new int[] { 2 };
+        Runnable runnable = () -> System.out.println(IntStream
+          .of(1, 2, 3)
+          .map(val -> val + holder[0])
+          .sum());
+
+        new Thread(runnable).start();
+
+        // simulating some processing
+        try {
+            Thread.sleep(new Random().nextInt(3) * 1000L);
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
+
+        holder[0] = 0;
+    }
+
+}

core-java-lang-oop-2/.gitignore

@@ -0,0 +1,4 @@
+target/
+.idea/
+bin/
+*.iml

core-java-lang-oop-2/README.md

@@ -0,0 +1,6 @@
+=========
+
+## Core Java Lang OOP 2 Cookbooks and Examples
+
+### Relevant Articles: 
+- [Generic Constructors in Java](https://www.baeldung.com/java-generic-constructors)

core-java-lang-oop-2/pom.xml

@@ -0,0 +1,27 @@
+<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</groupId>
+    <artifactId>core-java-lang-oop-2</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-lang-oop-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>
+
+    <build>
+        <finalName>core-java-lang-oop-2</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+</project>

core-java-lang-oop-2/src/main/java/com/baeldung/anonymous/Book.java

@@ -0,0 +1,15 @@
+package com.baeldung.anonymous;
+
+public class Book {
+
+    final String title;
+    
+    public Book(String title) {
+        this.title = title;
+    }
+    
+    public String description() {
+        return "Title: " + title;
+    }
+
+}

core-java-lang-oop-2/src/main/java/com/baeldung/anonymous/Main.java

@@ -0,0 +1,64 @@
+package com.baeldung.anonymous;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Code snippet that illustrates the usage of anonymous classes.
+ * 
+ * Note that use of Runnable instances in this example does not demonstrate their
+ * common use.
+ * 
+ * @author A. Shcherbakov
+ *
+ */
+public class Main {
+
+    public static void main(String[] args) {
+        final List<Runnable> actions = new ArrayList<Runnable>(2);
+
+        Runnable action = new Runnable() {
+            @Override
+            public void run() {
+                System.out.println("Hello from runnable.");
+            }
+
+        };
+        actions.add(action);
+
+        Book book = new Book("Design Patterns") {
+            @Override
+            public String description() {
+                return "Famous GoF book.";
+            }
+        };
+
+        System.out.println(String.format("Title: %s, description: %s", book.title, book.description()));
+
+        actions.add(new Runnable() {
+            @Override
+            public void run() {
+                System.out.println("Hello from runnable #2.");
+
+            }
+        });
+
+        int count = 1;
+
+        Runnable action2 = new Runnable() {
+            static final int x = 0;
+            // static int y = 0;
+
+            @Override
+            public void run() {
+                System.out.println(String.format("Runnable with captured variables: count = %s, x = %s", count, x));
+            }
+        };
+        actions.add(action2);
+
+        for (Runnable a : actions) {
+            a.run();
+        }
+    }
+
+}

core-java-lang-oop-2/src/main/java/com/baeldung/generics/Entry.java

@@ -0,0 +1,38 @@
+package com.baeldung.generics;
+
+import java.io.Serializable;
+
+public class Entry {
+    private String data;
+    private int rank;
+
+    // non-generic constructor
+    public Entry(String data, int rank) {
+        this.data = data;
+        this.rank = rank;
+    }
+
+    // generic constructor
+    public <E extends Rankable & Serializable> Entry(E element) {
+        this.data = element.toString();
+        this.rank = element.getRank();
+    }
+
+    // getters and setters
+    public String getData() {
+        return data;
+    }
+
+    public void setData(String data) {
+        this.data = data;
+    }
+
+    public int getRank() {
+        return rank;
+    }
+
+    public void setRank(int rank) {
+        this.rank = rank;
+    }
+
+}

core-java-lang-oop-2/src/main/java/com/baeldung/generics/GenericEntry.java

@@ -0,0 +1,53 @@
+package com.baeldung.generics;
+
+import java.io.Serializable;
+import java.util.Optional;
+
+public class GenericEntry<T> {
+    private T data;
+    private int rank;
+
+    // non-generic constructor
+    public GenericEntry(int rank) {
+        this.rank = rank;
+    }
+
+    // generic constructor
+    public GenericEntry(T data, int rank) {
+        this.data = data;
+        this.rank = rank;
+    }
+
+    // generic constructor with different type
+    public <E extends Rankable & Serializable> GenericEntry(E element) {
+        this.data = (T) element;
+        this.rank = element.getRank();
+    }
+
+    // generic constructor with different type and wild card
+    public GenericEntry(Optional<? extends Rankable> optional) {
+        if (optional.isPresent()) {
+            this.data = (T) optional.get();
+            this.rank = optional.get()
+                .getRank();
+        }
+    }
+
+    // getters and setters
+    public T getData() {
+        return data;
+    }
+
+    public void setData(T data) {
+        this.data = data;
+    }
+
+    public int getRank() {
+        return rank;
+    }
+
+    public void setRank(int rank) {
+        this.rank = rank;
+    }
+
+}

core-java-lang-oop-2/src/main/java/com/baeldung/generics/MapEntry.java

@@ -0,0 +1,34 @@
+package com.baeldung.generics;
+
+public class MapEntry<K, V> {
+    private K key;
+    private V value;
+
+    public MapEntry() {
+        super();
+    }
+
+    // generic constructor with two parameters
+    public MapEntry(K key, V value) {
+        this.key = key;
+        this.value = value;
+    }
+
+    // getters and setters
+    public K getKey() {
+        return key;
+    }
+
+    public void setKey(K key) {
+        this.key = key;
+    }
+
+    public V getValue() {
+        return value;
+    }
+
+    public void setValue(V value) {
+        this.value = value;
+    }
+
+}

core-java-lang-oop-2/src/main/java/com/baeldung/generics/Product.java

@@ -0,0 +1,50 @@
+package com.baeldung.generics;
+
+import java.io.Serializable;
+
+public class Product implements Rankable, Serializable {
+    private String name;
+    private double price;
+    private int sales;
+
+    public Product(String name, double price) {
+        this.name = name;
+        this.price = price;
+    }
+
+    @Override
+    public int getRank() {
+        return sales;
+    }
+
+    @Override
+    public String toString() {
+        return "Product [name=" + name + ", price=" + price + ", sales=" + sales + "]";
+    }
+
+    // getters and setters
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public void setPrice(double price) {
+        this.price = price;
+    }
+
+    public int getSales() {
+        return sales;
+    }
+
+    public void setSales(int sales) {
+        this.sales = sales;
+    }
+
+}

core-java-lang-oop-2/src/main/java/com/baeldung/generics/Rankable.java

@@ -0,0 +1,5 @@
+package com.baeldung.generics;
+
+public interface Rankable {
+    public int getRank();
+}

core-java-lang-oop-2/src/main/java/com/baeldung/supertypecompilerexception/MyClass.java

@@ -0,0 +1,16 @@
+package com.baeldung.supertypecompilerexception;
+
+public class MyClass {
+
+    private int myField1 = 10;
+    private int myField2;
+
+    public MyClass() {
+        //uncomment this to see the supertype compiler error:
+        //this(myField1);
+    }
+
+    public MyClass(int i) {
+        myField2 = i;
+    }
+}

core-java-lang-oop-2/src/main/java/com/baeldung/supertypecompilerexception/MyClassSolution1.java

@@ -0,0 +1,15 @@
+package com.baeldung.supertypecompilerexception;
+
+public class MyClassSolution1 {
+
+    private int myField1 = 10;
+    private int myField2;
+
+    public MyClassSolution1() {
+        myField2 = myField1;
+    }
+
+    public MyClassSolution1(int i) {
+        myField2 = i;
+    }
+}

core-java-lang-oop-2/src/main/java/com/baeldung/supertypecompilerexception/MyClassSolution2.java

@@ -0,0 +1,19 @@
+package com.baeldung.supertypecompilerexception;
+
+public class MyClassSolution2 {
+
+    private int myField1 = 10;
+    private int myField2;
+
+    public MyClassSolution2() {
+        setupMyFields(myField1);
+    }
+
+    public MyClassSolution2(int i) {
+        setupMyFields(i);
+    }
+
+    private void setupMyFields(int i) {
+        myField2 = i;
+    }
+}

core-java-lang-oop-2/src/main/java/com/baeldung/supertypecompilerexception/MyClassSolution3.java

@@ -0,0 +1,15 @@
+package com.baeldung.supertypecompilerexception;
+
+public class MyClassSolution3 {
+
+    private static final int SOME_CONSTANT = 10;
+    private int myField2;
+
+    public MyClassSolution3() {
+        this(SOME_CONSTANT);
+    }
+
+    public MyClassSolution3(int i) {
+        myField2 = i;
+    }
+}

core-java-lang-oop-2/src/main/java/com/baeldung/supertypecompilerexception/MyException.java

@@ -0,0 +1,14 @@
+package com.baeldung.supertypecompilerexception;
+
+public class MyException extends RuntimeException {
+    private int errorCode = 0;
+
+    public MyException(String message) {
+        //uncomment this to see the supertype compiler error:
+        //super(message + getErrorCode());
+    }
+
+    public int getErrorCode() {
+        return errorCode;
+    }
+}

core-java-lang-oop-2/src/test/java/com/baeldung/generics/GenericConstructorUnitTest.java

@@ -0,0 +1,76 @@
+package com.baeldung.generics;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+import java.io.Serializable;
+import java.util.Optional;
+
+import org.junit.Test;
+
+public class GenericConstructorUnitTest {
+
+    @Test
+    public void givenNonGenericConstructor_whenCreateNonGenericEntry_thenOK() {
+        Entry entry = new Entry("sample", 1);
+
+        assertEquals("sample", entry.getData());
+        assertEquals(1, entry.getRank());
+    }
+
+    @Test
+    public void givenGenericConstructor_whenCreateNonGenericEntry_thenOK() {
+        Product product = new Product("milk", 2.5);
+        product.setSales(30);
+        Entry entry = new Entry(product);
+
+        assertEquals(product.toString(), entry.getData());
+        assertEquals(30, entry.getRank());
+    }
+
+    @Test
+    public void givenNonGenericConstructor_whenCreateGenericEntry_thenOK() {
+        GenericEntry<String> entry = new GenericEntry<String>(1);
+
+        assertNull(entry.getData());
+        assertEquals(1, entry.getRank());
+    }
+
+    @Test
+    public void givenGenericConstructor_whenCreateGenericEntry_thenOK() {
+        GenericEntry<String> entry = new GenericEntry<String>("sample", 1);
+
+        assertEquals("sample", entry.getData());
+        assertEquals(1, entry.getRank());
+    }
+
+    @Test
+    public void givenGenericConstructorWithDifferentType_whenCreateGenericEntry_thenOK() {
+        Product product = new Product("milk", 2.5);
+        product.setSales(30);
+        GenericEntry<Serializable> entry = new GenericEntry<Serializable>(product);
+
+        assertEquals(product, entry.getData());
+        assertEquals(30, entry.getRank());
+    }
+
+    @Test
+    public void givenGenericConstructorWithWildCard_whenCreateGenericEntry_thenOK() {
+        Product product = new Product("milk", 2.5);
+        product.setSales(30);
+        Optional<Product> optional = Optional.of(product);
+        GenericEntry<Serializable> entry = new GenericEntry<Serializable>(optional);
+
+        assertEquals(product, entry.getData());
+        assertEquals(30, entry.getRank());
+    }
+
+    @Test
+    public void givenGenericConstructor_whenCreateGenericEntryWithTwoTypes_thenOK() {
+        MapEntry<String, Integer> entry = new MapEntry<String, Integer>("sample", 1);
+
+        assertEquals("sample", entry.getKey());
+        assertEquals(1, entry.getValue()
+            .intValue());
+    }
+}

core-java-lang-oop/README.md

@@ -10,7 +10,7 @@
 - [How to Make a Deep Copy of an Object in Java](http://www.baeldung.com/java-deep-copy)
 - [Guide to Inheritance in Java](http://www.baeldung.com/java-inheritance)
 - [Object Type Casting in Java](http://www.baeldung.com/java-type-casting)
-- [The "final" Keyword in Java](http://www.baeldung.com/java-final)
+- [The “final” Keyword in Java](http://www.baeldung.com/java-final)
 - [Type Erasure in Java Explained](http://www.baeldung.com/java-type-erasure)
 - [Pass-By-Value as a Parameter Passing Mechanism in Java](http://www.baeldung.com/java-pass-by-value-or-pass-by-reference)
 - [Variable and Method Hiding in Java](http://www.baeldung.com/java-variable-method-hiding)

core-java-lang/README.md

@@ -12,7 +12,7 @@
 - [Dynamic Proxies in Java](http://www.baeldung.com/java-dynamic-proxies)
 - [Java Double Brace Initialization](http://www.baeldung.com/java-double-brace-initialization)
 - [Guide to the Diamond Operator in Java](http://www.baeldung.com/java-diamond-operator)
-- [Quick Example - Comparator vs Comparable in Java](http://www.baeldung.com/java-comparator-comparable)
+- [Comparator and Comparable in Java](http://www.baeldung.com/java-comparator-comparable)
 - [The Java continue and break Keywords](http://www.baeldung.com/java-continue-and-break)
 - [Nested Classes in Java](http://www.baeldung.com/java-nested-classes)
 - [A Guide to Inner Interfaces in Java](http://www.baeldung.com/java-inner-interfaces)

core-java-networking/README.md

@@ -14,4 +14,5 @@
 - [A Guide to Java Sockets](http://www.baeldung.com/a-guide-to-java-sockets)
 - [Guide to Java URL Encoding/Decoding](http://www.baeldung.com/java-url-encoding-decoding)
 - [Do a Simple HTTP Request in Java](http://www.baeldung.com/java-http-request)
-- [Difference between URL and URI](http://www.baeldung.com/java-url-vs-uri)
+- [Difference between URL and URI](http://www.baeldung.com/java-url-vs-uri)
+- [Read an InputStream using the Java Server Socket](https://www.baeldung.com/java-inputstream-server-socket)

core-java-networking/src/main/java/com/baeldung/networking/cookies/ProxyAcceptCookiePolicy.java

@@ -17,8 +17,8 @@ public class ProxyAcceptCookiePolicy implements CookiePolicy {
             host = uri.getHost();
         }
 
-        if (!HttpCookie.domainMatches(acceptedProxy, host)) {
-            return false;
+        if (HttpCookie.domainMatches(acceptedProxy, host)) {
+            return true;
         }
 
         return CookiePolicy.ACCEPT_ORIGINAL_SERVER.shouldAccept(uri, cookie);

core-java/README.md

@@ -29,7 +29,7 @@
 - [What is the serialVersionUID?](http://www.baeldung.com/java-serial-version-uid)
 - [A Guide to the ResourceBundle](http://www.baeldung.com/java-resourcebundle)
 - [Class Loaders in Java](http://www.baeldung.com/java-classloaders)
-- [Guide to Java Clock Class](http://www.baeldung.com/java-clock)
+- [Guide to the Java Clock Class](http://www.baeldung.com/java-clock)
 - [Importance of Main Manifest Attribute in a Self-Executing JAR](http://www.baeldung.com/java-jar-executable-manifest-main-class)
 - [Java Global Exception Handler](http://www.baeldung.com/java-global-exception-handler)
 - [How to Get the Size of an Object in Java](http://www.baeldung.com/java-size-of-object)

core-kotlin-2/README.md

@@ -2,5 +2,8 @@
 
 - [Void Type in Kotlin](https://www.baeldung.com/kotlin-void-type)
 - [How to use Kotlin Range Expressions](https://www.baeldung.com/kotlin-ranges)
+- [Creating a Kotlin Range Iterator on a Custom Object](https://www.baeldung.com/kotlin-custom-range-iterator)
+- [Kotlin Scope Functions](https://www.baeldung.com/kotlin-scope-functions)
+- [Kotlin Annotations](https://www.baeldung.com/kotlin-annotations)
 - [Split a List into Parts in Kotlin](https://www.baeldung.com/kotlin-split-list-into-parts)
-- [String Comparison in Kotlin](https://www.baeldung.com/kotlin-string-comparison)
+- [String Comparison in Kotlin](https://www.baeldung.com/kotlin-string-comparison)

core-kotlin-2/build.gradle

@@ -5,7 +5,7 @@ version '1.0-SNAPSHOT'
 
 
 buildscript {
-    ext.kotlin_version = '1.2.41'
+    ext.kotlin_version = '1.3.30'
 
     repositories {
         mavenCentral()
@@ -26,8 +26,6 @@ sourceCompatibility = 1.8
 compileKotlin { kotlinOptions.jvmTarget = "1.8" }
 compileTestKotlin { kotlinOptions.jvmTarget = "1.8" }
 
-kotlin { experimental { coroutines "enable" } }
-
 repositories {
     mavenCentral()
     jcenter()
@@ -39,10 +37,22 @@ sourceSets {
             srcDirs 'com/baeldung/ktor'
         }
     }
+}
 
+test {
+    useJUnitPlatform()
+    testLogging {
+        events "passed", "skipped", "failed"
+    }
 }
 
 dependencies {
-    compile "ch.qos.logback:logback-classic:1.2.1"
-    testCompile group: 'junit', name: 'junit', version: '4.12'
-}
+    implementation "ch.qos.logback:logback-classic:1.2.1"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:${kotlin_version}"
+    testImplementation 'org.junit.jupiter:junit-jupiter:5.4.2'
+    testImplementation 'junit:junit:4.12'
+    testImplementation 'org.assertj:assertj-core:3.12.2'
+    testImplementation 'org.mockito:mockito-core:2.27.0'
+    testImplementation "org.jetbrains.kotlin:kotlin-test:${kotlin_version}"
+    testImplementation "org.jetbrains.kotlin:kotlin-test-junit5:${kotlin_version}"
+}

core-kotlin-2/gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.4-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-bin.zip

core-kotlin-2/gradlew

@@ -1,5 +1,21 @@
 #!/usr/bin/env sh
 
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
 ##############################################################################
 ##
 ##  Gradle start up script for UN*X
@@ -28,7 +44,7 @@ APP_NAME="Gradle"
 APP_BASE_NAME=`basename "$0"`
 
 # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS=""
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD="maximum"

core-kotlin-2/gradlew.bat

@@ -1,3 +1,19 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      http://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
 @if "%DEBUG%" == "" @echo off
 @rem ##########################################################################
 @rem
@@ -14,7 +30,7 @@ set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome

core-kotlin-2/pom.xml

@@ -20,9 +20,21 @@
             <version>${kotlin.version}</version>
         </dependency>
         <dependency>
-            <groupId>org.junit.platform</groupId>
-            <artifactId>junit-platform-runner</artifactId>
-            <version>${junit.platform.version}</version>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${junit.jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>${mockito.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>net.bytebuddy</groupId>
+            <artifactId>byte-buddy</artifactId>
+            <version>${byte-buddy.version}</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -37,6 +49,12 @@
             <version>${kotlin.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-test-junit5</artifactId>
+            <version>${kotlin.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -69,10 +87,11 @@
     </build>
 
     <properties>
-        <kotlin.version>1.2.71</kotlin.version>
-        <junit.platform.version>1.1.1</junit.platform.version>
-        <junit.vintage.version>5.2.0</junit.vintage.version>
+        <kotlin.version>1.3.30</kotlin.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>
     </properties>
 
-</project>
+</project>

core-kotlin-2/src/test/kotlin/com/baeldung/console/ConsoleIOUnitTest.kt

@@ -0,0 +1,79 @@
+package com.baeldung.console
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.Test
+import org.mockito.Mockito.`when`
+import org.mockito.Mockito.mock
+import java.io.BufferedReader
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.Console
+import java.io.InputStreamReader
+import java.io.PrintStream
+import java.util.*
+
+
+class ConsoleIOUnitTest {
+
+    @Test
+    fun givenText_whenPrint_thenPrintText() {
+        val expectedTest = "Hello from Kotlin"
+        val out = ByteArrayOutputStream()
+        System.setOut(PrintStream(out))
+
+        print(expectedTest)
+        out.flush()
+        val printedText = String(out.toByteArray())
+
+        assertThat(printedText).isEqualTo(expectedTest)
+    }
+
+    @Test
+    fun givenInput_whenRead_thenReadText() {
+        val expectedTest = "Hello from Kotlin"
+        val input = ByteArrayInputStream(expectedTest.toByteArray())
+        System.setIn(input)
+
+        val readText = readLine()
+
+        assertThat(readText).isEqualTo(expectedTest)
+    }
+
+    @Test
+    fun givenInput_whenReadWithScanner_thenReadText() {
+        val expectedTest = "Hello from Kotlin"
+        val scanner = Scanner(ByteArrayInputStream(expectedTest.toByteArray()))
+
+        val readText = scanner.nextLine()
+
+        assertThat(readText).isEqualTo(expectedTest)
+    }
+
+    @Test
+    fun givenInput_whenReadWithBufferedReader_thenReadText() {
+        val expectedTest = "Hello from Kotlin"
+        val reader = BufferedReader(InputStreamReader(ByteArrayInputStream(expectedTest.toByteArray())))
+
+        val readText = reader.readLine()
+
+        assertThat(readText).isEqualTo(expectedTest)
+    }
+
+    @Test
+    fun givenInput_whenReadWithConsole_thenReadText() {
+        val expectedTest = "Hello from Kotlin"
+        val console = mock(Console::class.java)
+        `when`(console.readLine()).thenReturn(expectedTest)
+
+        val readText = console.readLine()
+
+        assertThat(readText).isEqualTo(expectedTest)
+    }
+
+    @AfterEach
+    fun resetIO() {
+        System.setOut(System.out)
+        System.setIn(System.`in`)
+    }
+}

core-kotlin-2/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker

@@ -0,0 +1 @@
+mock-maker-inline

core-kotlin-io/.gitignore

@@ -0,0 +1,11 @@
+/bin/
+
+#ignore gradle
+.gradle/
+
+
+#ignore build and generated files
+build/
+node/
+target/
+out/

core-kotlin-io/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [InputStream to String in Kotlin](https://www.baeldung.com/kotlin-inputstream-to-string)

core-kotlin-io/pom.xml

@@ -0,0 +1,78 @@
+<?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>
+    <artifactId>core-kotlin-io</artifactId>
+    <name>core-kotlin-io</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-kotlin</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../parent-kotlin</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-stdlib-jdk8</artifactId>
+            <version>${kotlin.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit.platform.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-test</artifactId>
+            <version>${kotlin.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <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>
+        </plugins>
+    </build>
+
+    <properties>
+        <kotlin.version>1.2.71</kotlin.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>
+    </properties>
+
+</project>

core-kotlin-io/src/main/kotlin/com/baeldung/inputstream/InputStreamExtension.kt

@@ -0,0 +1,18 @@
+package com.baeldung.inputstream
+
+import java.io.InputStream
+
+fun InputStream.readUpToChar(stopChar: Char): String {
+    val stringBuilder = StringBuilder()
+    var currentChar = this.read().toChar()
+    while (currentChar != stopChar) {
+        stringBuilder.append(currentChar)
+        currentChar = this.read().toChar()
+        if (this.available() <= 0) {
+            stringBuilder.append(currentChar)
+            break
+        }
+    }
+    return stringBuilder.toString()
+}
+

core-kotlin-io/src/test/kotlin/com/baeldung/inputstream/InputStreamToStringTest.kt

@@ -0,0 +1,72 @@
+package com.baeldung.inputstream
+
+import kotlinx.io.core.use
+import org.junit.Test
+import java.io.BufferedReader
+import java.io.File
+import kotlin.test.assertEquals
+
+class InputStreamToStringTest {
+    private val fileName = "src/test/resources/inputstream2string.txt"
+    private val endOfLine = System.lineSeparator()
+    private val fileFullContent = "Computer programming can be a hassle$endOfLine" +
+            "It's like trying to take a defended castle"
+
+    @Test
+    fun whenReadFileWithBufferedReader_thenFullFileContentIsReadAsString() {
+        val file = File(fileName)
+        val inputStream = file.inputStream()
+        val content = inputStream.bufferedReader().use(BufferedReader::readText)
+        assertEquals(fileFullContent, content)
+    }
+    @Test
+    fun whenReadFileWithBufferedReaderReadText_thenFullFileContentIsReadAsString() {
+        val file = File(fileName)
+        val inputStream = file.inputStream()
+        val reader = BufferedReader(inputStream.reader())
+        var content: String
+        try {
+            content = reader.readText()
+        } finally {
+            reader.close()
+        }
+        assertEquals(fileFullContent, content)
+    }
+    @Test
+    fun whenReadFileWithBufferedReaderManually_thenFullFileContentIsReadAsString() {
+        val file = File(fileName)
+        val inputStream = file.inputStream()
+        val reader = BufferedReader(inputStream.reader())
+        val content = StringBuilder()
+        try {
+            var line = reader.readLine()
+            while (line != null) {
+                content.append(line)
+                line = reader.readLine()
+            }
+        } finally {
+            reader.close()
+        }
+        assertEquals(fileFullContent.replace(endOfLine, ""), content.toString())
+
+    }
+
+    @Test
+    fun whenReadFileUpToStopChar_thenPartBeforeStopCharIsReadAsString() {
+        val file = File(fileName)
+        val inputStream = file.inputStream()
+        val content = inputStream.use { it.readUpToChar(' ') }
+        assertEquals("Computer", content)
+    }
+
+    @Test
+    fun whenReadFileWithoutContainingStopChar_thenFullFileContentIsReadAsString() {
+        val file = File(fileName)
+        val inputStream = file.inputStream()
+        val content = inputStream.use { it.readUpToChar('-') }
+        assertEquals(fileFullContent, content)
+    }
+
+
+}
+

core-kotlin-io/src/test/resources/inputstream2string.txt

@@ -0,0 +1,2 @@
+Computer programming can be a hassle
+It's like trying to take a defended castle

core-kotlin/README.md

@@ -1,7 +1,7 @@
 ## Relevant articles:
 
 - [Introduction to the Kotlin Language](http://www.baeldung.com/kotlin)
-- [A guide to the “when{}” block in Kotlin](http://www.baeldung.com/kotlin-when)
+- [Guide to the “when{}” Block in Kotlin](http://www.baeldung.com/kotlin-when)
 - [Comprehensive Guide to Null Safety in Kotlin](http://www.baeldung.com/kotlin-null-safety)
 - [Kotlin Java Interoperability](http://www.baeldung.com/kotlin-java-interoperability)
 - [Difference Between “==” and “===” operators in Kotlin](http://www.baeldung.com/kotlin-equality-operators)

core-kotlin/src/main/kotlin/com/baeldung/kotlin/StringUtil.kt

@@ -0,0 +1,9 @@
+@file:JvmName("Strings")
+package com.baeldung.kotlin
+
+fun String.escapeForXml() : String {
+    return this
+            .replace("&", "&")
+            .replace("<", "&lt;")
+            .replace(">", "&gt;")
+}

core-kotlin/src/test/java/com/baeldung/kotlin/StringUtilUnitTest.java

@@ -0,0 +1,30 @@
+package com.baeldung.kotlin;
+
+import kotlin.text.StringsKt;
+import org.junit.Assert;
+import org.junit.Test;
+
+import static com.baeldung.kotlin.Strings.*;
+
+
+public class StringUtilUnitTest {
+
+    @Test
+    public void shouldEscapeXmlTagsInString() {
+        String xml = "<a>hi</a>";
+
+        String escapedXml = escapeForXml(xml);
+
+        Assert.assertEquals("&lt;a&gt;hi&lt;/a&gt;", escapedXml);
+    }
+
+    @Test
+    public void callingBuiltInKotlinExtensionMethod() {
+        String name = "john";
+
+        String capitalizedName = StringsKt.capitalize(name);
+
+        Assert.assertEquals("John", capitalizedName);
+    }
+
+}

core-kotlin/src/test/kotlin/com/baeldung/kotlin/ExtensionMethods.kt

@@ -6,13 +6,6 @@ import org.junit.Test
 class ExtensionMethods {
     @Test
     fun simpleExtensionMethod() {
-        fun String.escapeForXml() : String {
-            return this
-                    .replace("&", "&")
-                    .replace("<", "&lt;")
-                    .replace(">", "&gt;")
-        }
-
         Assert.assertEquals("Nothing", "Nothing".escapeForXml())
         Assert.assertEquals("&lt;Tag&gt;", "<Tag>".escapeForXml())
         Assert.assertEquals("a&amp;b", "a&b".escapeForXml())

couchbase/README.md

@@ -3,7 +3,7 @@
 ### Relevant Articles:
 - [Introduction to Couchbase SDK for Java](http://www.baeldung.com/java-couchbase-sdk)
 - [Using Couchbase in a Spring Application](http://www.baeldung.com/couchbase-sdk-spring)
-- [Asynchronous Batch Opereations in Couchbase](http://www.baeldung.com/async-batch-operations-in-couchbase)
+- [Asynchronous Batch Operations in Couchbase](http://www.baeldung.com/async-batch-operations-in-couchbase)
 - [Querying Couchbase with MapReduce Views](http://www.baeldung.com/couchbase-query-mapreduce-view)
 - [Querying Couchbase with N1QL](http://www.baeldung.com/n1ql-couchbase)
 

gson/README.md

@@ -11,6 +11,6 @@
 - [Convert JSON to a Map Using Gson](https://www.baeldung.com/gson-json-to-map)
 - [Working with Primitive Values in Gson](https://www.baeldung.com/java-gson-primitives)
 - [Convert String to JsonObject with Gson](https://www.baeldung.com/gson-string-to-jsonobject)
-- [Mapping Multiple JSON Fields to One Java Field](https://www.baeldung.com/json-multiple-fields-single-java-field)
+- [Mapping Multiple JSON Fields to a Single Java Field](https://www.baeldung.com/json-multiple-fields-single-java-field)
 - [Serializing and Deserializing a List with Gson](https://www.baeldung.com/gson-list)
 

guava-collections-set/.gitignore

@@ -0,0 +1,13 @@
+*.class
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear

guava-collections-set/pom.xml

@@ -0,0 +1,37 @@
+<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</groupId>
+    <artifactId>guava-collections-set</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>guava-collections-set</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <!-- test scoped -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>guava-collections-set</finalName>
+    </build>
+
+    <properties>
+        <!-- util -->
+        <guava.version>27.1-jre</guava.version>
+        <!-- testing -->
+        <assertj.version>3.6.1</assertj.version>
+    </properties>
+
+</project>