Merge remote-tracking branch 'eugenp/master'

akka-http/pom.xml

@@ -0,0 +1,48 @@
+<?xml version="1.0"?>
+<project
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+	xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+
+	<modelVersion>4.0.0</modelVersion>
+	<artifactId>akka-http</artifactId>
+	<name>akka-http</name>
+
+	<parent>
+		<artifactId>parent-modules</artifactId>
+		<groupId>com.baeldung</groupId>
+		<version>1.0.0-SNAPSHOT</version>
+	</parent>
+
+	<dependencies>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-http_2.12</artifactId>
+			<version>${akka.http.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-stream_2.12</artifactId>
+			<version>2.5.11</version>
+		</dependency>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-http-jackson_2.12</artifactId>
+			<version>${akka.http.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-http-testkit_2.12</artifactId>
+			<version>${akka.http.version}</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+		<java.version>1.8</java.version>
+		<akka.http.version>10.0.11</akka.http.version>
+		<akka.stream.version>2.5.11</akka.stream.version>
+	</properties>
+</project>

akka-http/src/main/java/com/baeldung/akkahttp/User.java

@@ -0,0 +1,26 @@
+package com.baeldung.akkahttp;
+
+public class User {
+
+    private final Long id;
+
+    private final String name;
+
+    public User() {
+        this.name = "";
+        this.id = null;
+    }
+
+    public User(Long id, String name) {
+        this.name = name;
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public Long getId() {
+        return id;
+    }
+}

akka-http/src/main/java/com/baeldung/akkahttp/UserActor.java

@@ -0,0 +1,41 @@
+package com.baeldung.akkahttp;
+
+import akka.actor.AbstractActor;
+import akka.actor.Props;
+import akka.japi.pf.FI;
+import com.baeldung.akkahttp.UserMessages.ActionPerformed;
+import com.baeldung.akkahttp.UserMessages.CreateUserMessage;
+import com.baeldung.akkahttp.UserMessages.GetUserMessage;
+
+
+class UserActor extends AbstractActor {
+
+  private UserService userService = new UserService();
+
+  static Props props() {
+    return Props.create(UserActor.class);
+  }
+
+  @Override
+  public Receive createReceive() {
+    return receiveBuilder()
+            .match(CreateUserMessage.class, handleCreateUser())
+            .match(GetUserMessage.class, handleGetUser())
+            .build();
+  }
+
+  private FI.UnitApply<CreateUserMessage> handleCreateUser() {
+    return createUserMessageMessage -> {
+      userService.createUser(createUserMessageMessage.getUser());
+      sender().tell(new ActionPerformed(String.format("User %s created.", createUserMessageMessage.getUser()
+              .getName())), getSelf());
+    };
+  }
+
+  private FI.UnitApply<GetUserMessage> handleGetUser() {
+    return getUserMessageMessage -> {
+      sender().tell(userService.getUser(getUserMessageMessage.getUserId()), getSelf());
+    };
+  }
+
+}

akka-http/src/main/java/com/baeldung/akkahttp/UserMessages.java

@@ -0,0 +1,49 @@
+package com.baeldung.akkahttp;
+
+import java.io.Serializable;
+
+public interface UserMessages {
+
+  class ActionPerformed implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    private final String description;
+
+    public ActionPerformed(String description) {
+      this.description = description;
+    }
+
+    public String getDescription() {
+      return description;
+    }
+  }
+
+  class CreateUserMessage implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+    private final User user;
+
+    public CreateUserMessage(User user) {
+      this.user = user;
+    }
+
+    public User getUser() {
+      return user;
+    }
+  }
+
+  class GetUserMessage implements Serializable {
+    private static final long serialVersionUID = 1L;
+    private final Long userId;
+
+    public GetUserMessage(Long userId) {
+      this.userId = userId;
+    }
+
+    public Long getUserId() {
+      return userId;
+    }
+  }
+
+}

akka-http/src/main/java/com/baeldung/akkahttp/UserServer.java

@@ -0,0 +1,70 @@
+package com.baeldung.akkahttp;
+
+import java.util.Optional;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.TimeUnit;
+
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.http.javadsl.marshallers.jackson.Jackson;
+import akka.http.javadsl.model.StatusCodes;
+import akka.http.javadsl.server.HttpApp;
+import akka.http.javadsl.server.Route;
+import akka.pattern.PatternsCS;
+import akka.util.Timeout;
+import com.baeldung.akkahttp.UserMessages.ActionPerformed;
+import com.baeldung.akkahttp.UserMessages.CreateUserMessage;
+import com.baeldung.akkahttp.UserMessages.GetUserMessage;
+import scala.concurrent.duration.Duration;
+import static akka.http.javadsl.server.PathMatchers.*;
+
+class UserServer extends HttpApp {
+
+  private final ActorRef userActor;
+
+  Timeout timeout = new Timeout(Duration.create(5, TimeUnit.SECONDS));
+
+  UserServer(ActorRef userActor) {
+    this.userActor = userActor;
+  }
+
+  @Override
+  public Route routes() {
+    return path("users", this::postUser)
+            .orElse(path(segment("users").slash(longSegment()), id ->
+                    route(getUser(id))));
+  }
+
+  private Route getUser(Long id) {
+    return get(() -> {
+      CompletionStage<Optional<User>> user = PatternsCS.ask(userActor, new GetUserMessage(id), timeout)
+              .thenApply(obj -> (Optional<User>) obj);
+
+      return onSuccess(() -> user, performed -> {
+        if (performed.isPresent())
+          return complete(StatusCodes.OK, performed.get(), Jackson.marshaller());
+        else
+          return complete(StatusCodes.NOT_FOUND);
+      });
+    });
+  }
+
+  private Route postUser() {
+    return route(post(() -> entity(Jackson.unmarshaller(User.class), user -> {
+      CompletionStage<ActionPerformed> userCreated = PatternsCS.ask(userActor, new CreateUserMessage(user), timeout)
+              .thenApply(obj -> (ActionPerformed) obj);
+
+      return onSuccess(() -> userCreated, performed -> {
+        return complete(StatusCodes.CREATED, performed, Jackson.marshaller());
+      });
+    })));
+  }
+
+  public static void main(String[] args) throws Exception {
+    ActorSystem system = ActorSystem.create("userServer");
+    ActorRef userActor = system.actorOf(UserActor.props(), "userActor");
+    UserServer server = new UserServer(userActor);
+    server.startServer("localhost", 8080, system);
+  }
+
+}

akka-http/src/main/java/com/baeldung/akkahttp/UserService.java

@@ -0,0 +1,35 @@
+package com.baeldung.akkahttp;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public class UserService {
+
+  private final static List<User> users = new ArrayList<>();
+
+  static {
+    users.add(new User(1l, "Alice"));
+    users.add(new User(2l, "Bob"));
+    users.add(new User(3l, "Chris"));
+    users.add(new User(4l, "Dick"));
+    users.add(new User(5l, "Eve"));
+    users.add(new User(6l, "Finn"));
+  }
+
+  public Optional<User> getUser(Long id) {
+    return users.stream()
+            .filter(user -> user.getId()
+                    .equals(id))
+            .findFirst();
+  }
+
+  public void createUser(User user) {
+    users.add(user);
+  }
+
+  public List<User> getUsers(){
+    return users;
+  }
+
+}

akka-http/src/test/java/com/baeldung/akkahttp/UserServerUnitTest.java

@@ -0,0 +1,50 @@
+package com.baeldung.akkahttp;
+
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.http.javadsl.model.ContentTypes;
+import akka.http.javadsl.model.HttpEntities;
+import akka.http.javadsl.model.HttpRequest;
+import akka.http.javadsl.testkit.JUnitRouteTest;
+import akka.http.javadsl.testkit.TestRoute;
+import org.junit.Test;
+
+public class UserServerUnitTest extends JUnitRouteTest {
+
+  ActorSystem system = ActorSystem.create("helloAkkaHttpServer");
+
+  ActorRef userActorRef = system.actorOf(UserActor.props(), "userActor");
+
+  TestRoute appRoute = testRoute(new UserServer(userActorRef).routes());
+
+  @Test
+  public void whenRequest_thenActorResponds() {
+
+    appRoute.run(HttpRequest.GET("/users/1"))
+            .assertEntity(alice())
+            .assertStatusCode(200);
+
+    appRoute.run(HttpRequest.GET("/users/42"))
+            .assertStatusCode(404);
+
+    appRoute.run(HttpRequest.DELETE("/users/1"))
+            .assertStatusCode(200);
+
+    appRoute.run(HttpRequest.DELETE("/users/42"))
+            .assertStatusCode(200);
+
+    appRoute.run(HttpRequest.POST("/users")
+            .withEntity(HttpEntities.create(ContentTypes.APPLICATION_JSON, zaphod())))
+            .assertStatusCode(201);
+
+  }
+
+  private String alice() {
+    return "{\"id\":1,\"name\":\"Alice\"}";
+  }
+
+  private String zaphod() {
+    return "{\"id\":42,\"name\":\"Zaphod\"}";
+  }
+
+}

algorithms-miscellaneous-1/README.md

@@ -10,4 +10,6 @@
 - [Multi-Swarm Optimization Algorithm in Java](http://www.baeldung.com/java-multi-swarm-algorithm)
 - [String Search Algorithms for Large Texts](http://www.baeldung.com/java-full-text-search-algorithms)
 - [Check If a String Contains All The Letters of The Alphabet](https://www.baeldung.com/java-string-contains-all-letters)
-- [Find the Middle Element of a Linked List](http://www.baeldung.com/java-linked-list-middle-element)
+- [Find the Middle Element of a Linked List](http://www.baeldung.com/java-linked-list-middle-element)
+- [Calculate Factorial in Java](https://www.baeldung.com/java-calculate-factorial)
+- [Find Substrings That Are Palindromes in Java](https://www.baeldung.com/java-palindrome-substrings)

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/string/SubstringPalindrome.java

@@ -1,4 +1,4 @@
-package com.baeldung.string;
+package com.baeldung.algorithms.string;
 
 import java.util.HashSet;
 import java.util.Set;

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/string/SubstringPalindromeUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.string;
+package com.baeldung.algorithms.string;
 
 import static org.junit.Assert.assertEquals;
 import java.util.HashSet;

apache-curator/pom.xml

@@ -59,7 +59,7 @@
     <properties>
         <curator.version>4.0.1</curator.version>
         <zookeeper.version>3.4.11</zookeeper.version>
-        <jackson-databind.version>2.9.4</jackson-databind.version>
+        <jackson-databind.version>2.9.7</jackson-databind.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
         <avaitility.version>1.7.0</avaitility.version>

core-java-11/README.md

@@ -0,0 +1,5 @@
+### Relevant articles
+
+- [Java 11 Single File Source Code](https://www.baeldung.com/java-single-file-source-code)
+- [Java 11 Local Variable Syntax for Lambda Parameters](https://www.baeldung.com/java-var-lambda-params)
+

core-java-11/src/main/java/com/baeldung/add

@@ -0,0 +1,12 @@
+#!/usr/local/bin/java --source 11
+
+import java.util.Arrays;
+
+public class Addition
+{
+    public static void main(String[] args) {
+        System.out.println(Arrays.stream(args)
+          .mapToInt(Integer::parseInt)
+          .sum());
+    }
+}

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

@@ -0,0 +1,43 @@
+package com.baeldung;
+
+import static org.hamcrest.CoreMatchers.is;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class NewStringAPIUnitTest {
+
+    @Test
+    public void whenRepeatStringTwice_thenGetStringTwice() {
+        String output = "La ".repeat(2) + "Land";
+
+        is(output).equals("La La Land");
+    }
+
+    @Test
+    public void whenStripString_thenReturnStringWithoutWhitespaces() {
+        is("\n\t  hello   \u2005".strip()).equals("hello");
+    }
+
+    @Test
+    public void whenTrimAdvanceString_thenReturnStringWithWhitespaces() {
+        is("\n\t  hello   \u2005".trim()).equals("hello   \u2005");
+    }
+
+    @Test
+    public void whenBlankString_thenReturnTrue() {
+        assertTrue("\n\t\u2005  ".isBlank());
+    }
+
+    @Test
+    public void whenMultilineString_thenReturnNonEmptyLineCount() {
+        String multilineStr = "This is\n \n a multiline\n string.";
+
+        long lineCount = multilineStr.lines()
+          .filter(String::isBlank)
+          .count();
+
+        is(lineCount).equals(3L);
+    }
+}

core-java-11/src/test/java/com/baeldung/optional/OptionalUnitTest.java

@@ -0,0 +1,23 @@
+package com.baeldung.optional;
+
+import org.junit.Test;
+
+import java.util.Optional;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Unit tests for {@link Optional} in Java 11.
+ */
+public class OptionalUnitTest {
+
+    @Test
+    public void givenAnEmptyOptional_isEmpty_thenBehavesAsExpected() {
+        Optional<String> opt = Optional.of("Baeldung");
+        assertFalse(opt.isEmpty());
+
+        opt = Optional.ofNullable(null);
+        assertTrue(opt.isEmpty());
+    }
+}

core-java-8/README.md

@@ -15,7 +15,6 @@
 - [Guide to Java 8 Comparator.comparing()](http://www.baeldung.com/java-8-comparator-comparing)
 - [Guide To Java 8 Optional](http://www.baeldung.com/java-optional)
 - [Guide to the Java 8 forEach](http://www.baeldung.com/foreach-java)
-- [Java Base64 Encoding and Decoding](http://www.baeldung.com/java-base64-encode-and-decode)
 - [The Difference Between map() and flatMap()](http://www.baeldung.com/java-difference-map-and-flatmap)
 - [Static and Default Methods in Interfaces in Java](http://www.baeldung.com/java-static-default-methods)
 - [Efficient Word Frequency Calculator in Java](http://www.baeldung.com/java-word-frequency)

core-java-8/src/main/java/com/baeldung/interfaces/Electronic.java

@@ -0,0 +1,22 @@
+package com.baeldung.interfaces;
+
+public interface Electronic {
+    //Constant variable
+    public static final String LED = "LED";
+
+    //Abstract method
+    public int getElectricityUse();
+
+    // Static method
+    public static boolean isEnergyEfficient(String electtronicType) {
+        if (electtronicType.equals(LED)) {
+            return true;
+        }
+        return false;
+    }
+
+    //Default method
+    public default void printDescription() {
+        System.out.println("Electronic Description");
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/Employee.java

@@ -0,0 +1,15 @@
+package com.baeldung.interfaces;
+
+public class Employee {
+
+    private double salary;
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public void setSalary(double salary) {
+        this.salary = salary;
+    }
+
+}

core-java-8/src/main/java/com/baeldung/interfaces/EmployeeSalaryComparator.java

@@ -0,0 +1,18 @@
+package com.baeldung.interfaces;
+
+import java.util.Comparator;
+
+public class EmployeeSalaryComparator implements Comparator<Employee> {
+
+    @Override
+    public int compare(Employee employeeA, Employee employeeB) {
+
+        if(employeeA.getSalary() < employeeB.getSalary()){
+            return -1;
+        }else if(employeeA.getSalary() > employeeB.getSalary()){
+            return 1;
+        }else{
+            return 0;
+        }
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/HasColor.java

@@ -0,0 +1,5 @@
+package com.baeldung.interfaces;
+
+public interface HasColor {
+    public String getColor();
+}

core-java-8/src/main/java/com/baeldung/interfaces/Motorcycle.java

@@ -0,0 +1,10 @@
+package com.baeldung.interfaces;
+
+import com.baeldung.interfaces.multiinheritance.Transform;
+
+public class Motorcycle implements Transform {
+    @Override
+    public void transform() {
+        // Implementation
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/Truck.java

@@ -0,0 +1,8 @@
+package com.baeldung.interfaces;
+
+public class Truck extends Vehicle {
+    @Override
+    public void transform() {
+        // implementation
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/Vehicle.java

@@ -0,0 +1,6 @@
+package com.baeldung.interfaces;
+
+import com.baeldung.interfaces.multiinheritance.Transform;
+
+public abstract class Vehicle implements Transform {
+}

core-java-8/src/main/java/com/baeldung/interfaces/multiinheritance/Car.java

@@ -0,0 +1,13 @@
+package com.baeldung.interfaces.multiinheritance;
+
+public class Car implements Fly, Transform {
+    @Override
+    public void fly() {
+        System.out.println("I can Fly!!");
+    }
+
+    @Override
+    public void transform() {
+        System.out.println("I can Transform!!");
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/multiinheritance/Fly.java

@@ -0,0 +1,5 @@
+package com.baeldung.interfaces.multiinheritance;
+
+public abstract interface Fly{
+    void fly();
+}

core-java-8/src/main/java/com/baeldung/interfaces/multiinheritance/Transform.java

@@ -0,0 +1,10 @@
+package com.baeldung.interfaces.multiinheritance;
+
+public interface Transform {
+
+    void transform();
+
+    default void printSpecs(){
+        System.out.println("Transform Specification");
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/multiinheritance/Vehicle.java

@@ -0,0 +1,13 @@
+package com.baeldung.interfaces.multiinheritance;
+
+public class Vehicle implements Fly, Transform {
+    @Override
+    public void fly() {
+        System.out.println("I can Fly!!");
+    }
+
+    @Override
+    public void transform() {
+        System.out.println("I can Transform!!");
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/polymorphysim/Circle.java

@@ -0,0 +1,25 @@
+package com.baeldung.interfaces.polymorphysim;
+
+public class Circle implements Shape {
+
+    private double radius;
+
+    public Circle(double radius){
+        this.radius = radius;
+    }
+
+    @Override
+    public String name() {
+        return "Circle";
+    }
+
+    @Override
+    public double area() {
+        return Math.PI * (radius * radius);
+    }
+
+    @Override
+    public String getColor() {
+        return "green";
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/polymorphysim/DisplayShape.java

@@ -0,0 +1,26 @@
+package com.baeldung.interfaces.polymorphysim;
+
+import java.util.ArrayList;
+
+public class DisplayShape {
+
+    private ArrayList<Shape> shapes;
+
+    public ArrayList<Shape> getShapes() {
+        return shapes;
+    }
+
+    public DisplayShape() {
+        shapes = new ArrayList<>();
+    }
+
+    public void add(Shape shape) {
+        shapes.add(shape);
+    }
+
+    public void display() {
+        for (Shape shape : shapes) {
+            System.out.println(shape.name() + " area: " + shape.area());
+        }
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/polymorphysim/FunctionalMain.java

@@ -0,0 +1,23 @@
+package com.baeldung.interfaces.polymorphysim;
+
+import java.util.function.Predicate;
+
+public class FunctionalMain {
+
+public static void main(String[] args) {
+    Shape circleShape = new Circle(2);
+    Shape squareShape = new Square(2);
+
+    DisplayShape DisplayShape = new DisplayShape();
+    DisplayShape.add(circleShape);
+    DisplayShape.add(squareShape);
+
+    Predicate<Shape> checkArea = (shape) -> shape.area() < 5;
+
+    for (Shape shape : DisplayShape.getShapes()) {
+        if (checkArea.test(shape)) {
+            System.out.println(shape.name() + " " + shape.area());
+        }
+    }
+}
+}

core-java-8/src/main/java/com/baeldung/interfaces/polymorphysim/MainPolymorphic.java

@@ -0,0 +1,15 @@
+package com.baeldung.interfaces.polymorphysim;
+
+public class MainPolymorphic {
+    public static void main(String[] args){
+
+        Shape circleShape = new Circle(2);
+        Shape squareShape = new Square(2);
+
+        DisplayShape displayShape = new DisplayShape();
+        displayShape.add(circleShape);
+        displayShape.add(squareShape);
+
+        displayShape.display();
+    }
+}

core-java-8/src/main/java/com/baeldung/interfaces/polymorphysim/Shape.java

@@ -0,0 +1,9 @@
+package com.baeldung.interfaces.polymorphysim;
+
+import com.baeldung.interfaces.HasColor;
+
+public interface Shape extends HasColor {
+
+    public abstract String name();
+    public abstract double area();
+}

core-java-8/src/main/java/com/baeldung/interfaces/polymorphysim/Square.java

@@ -0,0 +1,25 @@
+package com.baeldung.interfaces.polymorphysim;
+
+public class Square implements Shape {
+
+    private double width;
+
+    public Square(double width) {
+        this.width = width;
+    }
+
+    @Override
+    public String name() {
+        return "Square";
+    }
+
+    @Override
+    public double area() {
+        return width * width;
+    }
+
+    @Override
+    public String getColor() {
+        return "red";
+    }
+}

core-java-8/src/test/java/com/baeldung/interfaces/PolymorphysimUnitTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.interfaces;
+
+import com.baeldung.interfaces.polymorphysim.Circle;
+import com.baeldung.interfaces.polymorphysim.Shape;
+import com.baeldung.interfaces.polymorphysim.Square;
+import org.assertj.core.api.Assertions;
+import org.junit.Test;
+
+public class PolymorphysimUnitTest {
+
+    @Test
+    public void whenInterfacePointsToCircle_CircleAreaMethodisBeingCalled(){
+        double expectedArea = 12.566370614359172;
+        Shape circle = new Circle(2);
+        double actualArea = circle.area();
+        Assertions.assertThat(actualArea).isEqualTo(expectedArea);
+    }
+
+    @Test
+    public void whenInterfacePointsToSquare_SquareAreaMethodisBeingCalled(){
+        double expectedArea = 4;
+        Shape square = new Square(2);
+        double actualArea = square.area();
+        Assertions.assertThat(actualArea).isEqualTo(expectedArea);
+    }
+}

core-java-9/README.md

@@ -9,7 +9,6 @@
 - [Java 9 Convenience Factory Methods for Collections](http://www.baeldung.com/java-9-collections-factory-methods) 
 - [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)
-- [Spring Security – Redirect to the Previous URL After Login](http://www.baeldung.com/spring-security-redirect-login)
 - [Java 9 Process API Improvements](http://www.baeldung.com/java-9-process-api)
 - [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)

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

@@ -7,6 +7,14 @@ public class Employee implements Serializable {
     private int id;
     private String name;
 
+    public Employee() {
+    }
+
+    public Employee(int id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
     public int getId() {
         return id;
     }

core-java-arrays/src/test/java/com/baeldung/sort/ArraySortUnitTest.java

@@ -0,0 +1,90 @@
+package com.baeldung.sort;
+
+import com.baeldung.arraycopy.model.Employee;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.stream.IntStream;
+
+import static org.junit.Assert.assertArrayEquals;
+
+public class ArraySortUnitTest {
+    private Employee[] employees;
+    private int[] numbers;
+    private String[] strings;
+
+    private Employee john = new Employee(6, "John");
+    private Employee mary = new Employee(3, "Mary");
+    private Employee david = new Employee(4, "David");
+
+    @Before
+    public void setup() {
+        createEmployeesArray();
+        createNumbersArray();
+        createStringArray();
+    }
+
+    private void createEmployeesArray() {
+        employees = new Employee[]{john, mary, david};
+    }
+
+    private void createNumbersArray() {
+        numbers = new int[]{-8, 7, 5, 9, 10, -2, 3};
+    }
+
+    private void createStringArray() {
+        strings = new String[]{"learning", "java", "with", "baeldung"};
+    }
+
+    @Test
+    public void givenIntArray_whenSortingAscending_thenCorrectlySorted() {
+        Arrays.sort(numbers);
+
+        assertArrayEquals(new int[]{-8, -2, 3, 5, 7, 9, 10}, numbers);
+    }
+
+    @Test
+    public void givenIntArray_whenSortingDescending_thenCorrectlySorted() {
+        numbers = IntStream.of(numbers).boxed().sorted(Comparator.reverseOrder()).mapToInt(i -> i).toArray();
+
+        assertArrayEquals(new int[]{10, 9, 7, 5, 3, -2, -8}, numbers);
+    }
+
+    @Test
+    public void givenStringArray_whenSortingAscending_thenCorrectlySorted() {
+        Arrays.sort(strings);
+
+        assertArrayEquals(new String[]{"baeldung", "java", "learning", "with"}, strings);
+    }
+
+    @Test
+    public void givenStringArray_whenSortingDescending_thenCorrectlySorted() {
+        Arrays.sort(strings, Comparator.reverseOrder());
+
+        assertArrayEquals(new String[]{"with", "learning", "java", "baeldung"}, strings);
+    }
+
+    @Test
+    public void givenObjectArray_whenSortingAscending_thenCorrectlySorted() {
+        Arrays.sort(employees, Comparator.comparing(Employee::getName));
+
+        assertArrayEquals(new Employee[]{david, john, mary}, employees);
+    }
+
+    @Test
+    public void givenObjectArray_whenSortingDescending_thenCorrectlySorted() {
+        Arrays.sort(employees, Comparator.comparing(Employee::getName).reversed());
+
+        assertArrayEquals(new Employee[]{mary, john, david}, employees);
+    }
+
+    @Test
+    public void givenObjectArray_whenSortingMultipleAttributesAscending_thenCorrectlySorted() {
+        Arrays.sort(employees, Comparator.comparing(Employee::getName).thenComparing(Employee::getId));
+
+        assertArrayEquals(new Employee[]{david, john, mary}, employees);
+    }
+
+}

core-java-collections-list/README.md

@@ -0,0 +1,28 @@
+=========
+
+## Core Java Collections List Cookbooks and Examples
+
+### Relevant Articles: 
+- [Immutable ArrayList in Java](http://www.baeldung.com/java-immutable-list)
+- [Guide to the Java ArrayList](http://www.baeldung.com/java-arraylist)
+- [Random List Element](http://www.baeldung.com/java-random-list-element)
+- [Removing all nulls from a List in Java](http://www.baeldung.com/java-remove-nulls-from-list)
+- [Removing all duplicates from a List in Java](http://www.baeldung.com/java-remove-duplicates-from-list)
+- [How to TDD a List Implementation in Java](http://www.baeldung.com/java-test-driven-list)
+- [Iterating Backward Through a List](http://www.baeldung.com/java-list-iterate-backwards)
+- [Add Multiple Items to an Java ArrayList](http://www.baeldung.com/java-add-items-array-list)
+- [Remove the First Element from a List](http://www.baeldung.com/java-remove-first-element-from-list)
+- [How to Find an Element in a List with Java](http://www.baeldung.com/find-list-element-java)
+- [Copy a List to Another List in Java](http://www.baeldung.com/java-copy-list-to-another)
+- [Finding Max/Min of a List or Collection](http://www.baeldung.com/java-collection-min-max)
+- [Collections.emptyList() vs. New List Instance](https://www.baeldung.com/java-collections-emptylist-new-list)
+- [Remove All Occurrences of a Specific Value from a List](https://www.baeldung.com/java-remove-value-from-list)
+- [Converting a Collection to ArrayList in Java](https://www.baeldung.com/java-convert-collection-arraylist)
+- [Check If Two Lists are Equal in Java](http://www.baeldung.com/java-test-a-list-for-ordinality-and-equality)
+- [Java 8 Streams: Find Items From One List Based On Values From Another List](https://www.baeldung.com/java-streams-find-list-items)
+- [A Guide to the Java LinkedList](http://www.baeldung.com/java-linkedlist)
+- [Java List UnsupportedOperationException](http://www.baeldung.com/java-list-unsupported-operation-exception)
+- [Java List Initialization in One Line](https://www.baeldung.com/java-init-list-one-line)
+- [Ways to Iterate Over a List in Java](https://www.baeldung.com/java-iterate-list)
+- [ClassCastException: Arrays$ArrayList cannot be cast to ArrayList](https://www.baeldung.com/java-classcastexception-arrays-arraylist)
+- [Flattening Nested Collections in Java](http://www.baeldung.com/java-flatten-nested-collections)

core-java-collections-list/pom.xml

@@ -0,0 +1,48 @@
+<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-list</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <name>core-java-collections-list</name>
+
+    <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.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <commons-collections4.version>4.1</commons-collections4.version>
+        <commons-lang3.version>3.8.1</commons-lang3.version>
+        <avaitility.version>1.7.0</avaitility.version>
+        <assertj.version>3.11.1</assertj.version>
+        <lombok.version>1.16.12</lombok.version>
+    </properties>
+</project>

core-java-collections-list/src/main/java/com/baeldung/list/multidimensional/ArrayListOfArrayList.java

@@ -0,0 +1,37 @@
+package com.baeldung.list.multidimensional;
+
+import java.util.ArrayList;
+
+public class ArrayListOfArrayList {
+
+    public static void main(String args[]) {
+
+        int vertex = 5;
+        ArrayList<ArrayList<Integer>> graph = new ArrayList<>(vertex);
+
+        //Initializing each element of ArrayList with ArrayList
+        for(int i=0; i< vertex; i++) {
+            graph.add(new ArrayList<Integer>());
+        }
+
+        //We can add any number of columns to each row
+        graph.get(0).add(1);
+        graph.get(0).add(5);
+        graph.get(1).add(0);
+        graph.get(1).add(2);
+        graph.get(2).add(1);
+        graph.get(2).add(3);
+        graph.get(3).add(2);
+        graph.get(3).add(4);
+        graph.get(4).add(3);
+        graph.get(4).add(5);
+
+        //Printing all the edges
+        for(int i=0; i<vertex; i++) {
+            for(int j=0; j<graph.get(i).size(); j++) {
+                System.out.println("Edge between vertex "+i+"and "+graph.get(i).get(j));
+            }
+        }
+    }
+
+}

core-java-collections-list/src/main/java/com/baeldung/list/multidimensional/ThreeDimensionalArrayList.java

@@ -0,0 +1,45 @@
+package com.baeldung.list.multidimensional;
+
+import java.util.ArrayList;
+
+public class ThreeDimensionalArrayList {
+
+    public static void main(String args[]) {
+        
+        int x_axis_length = 2;
+        int y_axis_length = 2;
+        int z_axis_length = 2;
+        ArrayList< ArrayList< ArrayList<String> > > space = new ArrayList<>(x_axis_length);
+
+        //Initializing each element of ArrayList with ArrayList< ArrayList<String> >
+        for(int i=0; i< x_axis_length; i++) {
+            space.add(new ArrayList< ArrayList<String> >(y_axis_length));
+            for(int j =0; j< y_axis_length; j++) {
+                space.get(i).add(new ArrayList<String>(z_axis_length));
+            }
+        }
+
+        //Set Red color for points (0,0,0) and (0,0,1)
+        space.get(0).get(0).add("Red");
+        space.get(0).get(0).add("Red");
+        //Set Blue color for points (0,1,0) and (0,1,1)
+        space.get(0).get(1).add("Blue");
+        space.get(0).get(1).add("Blue");
+        //Set Green color for points (1,0,0) and (1,0,1)
+        space.get(1).get(0).add("Green");
+        space.get(1).get(0).add("Green");
+        //Set Yellow color for points (1,1,0) and (1,1,1)
+        space.get(1).get(1).add("Yellow");
+        space.get(1).get(1).add("Yellow");
+
+        //Printing colors for all the points
+        for(int i=0; i<x_axis_length; i++) {
+            for(int j=0; j<y_axis_length; j++) {
+                for(int k=0; k<z_axis_length; k++) {
+                    System.out.println("Color of point ("+i+","+j+","+k+") is :"+space.get(i).get(j).get(k));
+                }
+            }
+        }
+    }
+
+}

core-java-collections-list/src/test/java/org/baeldung/RandomListElementUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package org.baeldung;
 
 import com.google.common.collect.Lists;
 import org.junit.Test;

core-java-collections-list/src/test/java/org/baeldung/java/lists/ListJUnitTest.java

@@ -0,0 +1,47 @@
+package org.baeldung.java.lists;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Set;
+import java.util.HashSet;
+
+import java.util.stream.Collectors;
+
+public class ListJUnitTest {
+
+    private final List<String> list1 = Arrays.asList("1", "2", "3", "4");
+    private final List<String> list2 = Arrays.asList("1", "2", "3", "4");
+    private final List<String> list3 = Arrays.asList("1", "2", "4", "3");
+
+    @Test
+    public void whenTestingForEquality_ShouldBeEqual() throws Exception {
+        Assert.assertEquals(list1, list2);
+        Assert.assertNotSame(list1, list2);
+        Assert.assertNotEquals(list1, list3);
+    }
+
+    @Test
+    public void whenIntersection_ShouldReturnCommonElements() throws Exception {
+        List<String> list = Arrays.asList("red", "blue", "blue", "green", "red");
+        List<String> otherList = Arrays.asList("red", "green", "green", "yellow");
+
+        Set<String> commonElements = new HashSet(Arrays.asList("red", "green"));
+
+        Set<String> result = list.stream()
+          .distinct()
+          .filter(otherList::contains)
+          .collect(Collectors.toSet());
+
+        Assert.assertEquals(commonElements, result);
+
+        Set<String> inverseResult = otherList.stream()
+          .distinct()
+          .filter(list::contains)
+          .collect(Collectors.toSet());
+
+        Assert.assertEquals(commonElements, inverseResult);
+    }
+}

core-java-collections/README.md

@@ -3,36 +3,21 @@
 ## Core Java Collections Cookbooks and Examples
 
 ### Relevant Articles: 
-- [Immutable ArrayList in Java](http://www.baeldung.com/java-immutable-list)
-- [Guide to the Java ArrayList](http://www.baeldung.com/java-arraylist)
-- [Random List Element](http://www.baeldung.com/java-random-list-element)
 - [Java - Combine Multiple Collections](http://www.baeldung.com/java-combine-multiple-collections)
-- [Removing all nulls from a List in Java](http://www.baeldung.com/java-remove-nulls-from-list)
-- [Removing all duplicates from a List in Java](http://www.baeldung.com/java-remove-duplicates-from-list)
-- [Flattening Nested Collections in Java](http://www.baeldung.com/java-flatten-nested-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)
 - [A Guide to HashSet in Java](http://www.baeldung.com/java-hashset)
 - [A Guide to TreeSet in Java](http://www.baeldung.com/java-tree-set)
-- [How to TDD a List Implementation in Java](http://www.baeldung.com/java-test-driven-list)
 - [Getting the Size of an Iterable in Java](http://www.baeldung.com/java-iterable-size)
-- [Iterating Backward Through a List](http://www.baeldung.com/java-list-iterate-backwards)
 - [How to Filter a Collection in Java](http://www.baeldung.com/java-collection-filtering)
-- [Add Multiple Items to an Java ArrayList](http://www.baeldung.com/java-add-items-array-list)
-- [Remove the First Element from a List](http://www.baeldung.com/java-remove-first-element-from-list)
 - [Initializing HashSet at the Time of Construction](http://www.baeldung.com/java-initialize-hashset)
 - [Removing the First Element of an Array](https://www.baeldung.com/java-array-remove-first-element)
 - [Fail-Safe Iterator vs Fail-Fast Iterator](http://www.baeldung.com/java-fail-safe-vs-fail-fast-iterator)
 - [Shuffling Collections In Java](http://www.baeldung.com/java-shuffle-collection)
-- [How to Find an Element in a List with Java](http://www.baeldung.com/find-list-element-java)
 - [An Introduction to Java.util.Hashtable Class](http://www.baeldung.com/java-hash-table)
-- [Copy a List to Another List in Java](http://www.baeldung.com/java-copy-list-to-another)
-- [Finding Max/Min of a List or Collection](http://www.baeldung.com/java-collection-min-max)
 - [Java Null-Safe Streams from Collections](https://www.baeldung.com/java-null-safe-streams-from-collections)
-- [Remove All Occurrences of a Specific Value from a List](https://www.baeldung.com/java-remove-value-from-list)
 - [Thread Safe LIFO Data Structure Implementations](https://www.baeldung.com/java-lifo-thread-safe)
-- [Collections.emptyList() vs. New List Instance](https://www.baeldung.com/java-collections-emptylist-new-list)
 - [Differences Between Collection.clear() and Collection.removeAll()](https://www.baeldung.com/java-collection-clear-vs-removeall)
 - [Performance of contains() in a HashSet vs ArrayList](https://www.baeldung.com/java-hashset-arraylist-contains-performance)
 - [Time Complexity of Java Collections](https://www.baeldung.com/java-collections-complexity)
@@ -40,15 +25,7 @@
 - [An Introduction to Synchronized Java Collections](https://www.baeldung.com/java-synchronized-collections)
 - [Guide to EnumSet](https://www.baeldung.com/java-enumset)
 - [Removing Elements from Java Collections](https://www.baeldung.com/java-collection-remove-elements)
-- [Converting a Collection to ArrayList in Java](https://www.baeldung.com/java-convert-collection-arraylist)
-- [Java 8 Streams: Find Items From One List Based On Values From Another List](https://www.baeldung.com/java-streams-find-list-items)
 - [Combining Different Types of Collections in Java](https://www.baeldung.com/java-combine-collections)
 - [Sorting in Java](http://www.baeldung.com/java-sorting)
-- [A Guide to the Java LinkedList](http://www.baeldung.com/java-linkedlist)
-- [Java List UnsupportedOperationException](http://www.baeldung.com/java-list-unsupported-operation-exception)
 - [Join and Split Arrays and Collections in Java](http://www.baeldung.com/java-join-and-split)
-- [Check If Two Lists are Equal in Java](http://www.baeldung.com/java-test-a-list-for-ordinality-and-equality)
-- [Java List Initialization in One Line](https://www.baeldung.com/java-init-list-one-line)
-- [ClassCastException: Arrays$ArrayList cannot be cast to ArrayList](https://www.baeldung.com/java-classcastexception-arrays-arraylist)
-- [A Guide to EnumMap](https://www.baeldung.com/java-enum-map)
-- [Ways to Iterate Over a List in Java](https://www.baeldung.com/java-iterate-list)
+- [A Guide to EnumMap](https://www.baeldung.com/java-enum-map)

core-java-collections/src/test/java/com/baeldung/hashmapvshashtable/HashmapVsHashtableDifferenceUnitTest.java

@@ -0,0 +1,98 @@
+package com.baeldung.hashmapvshashtable;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Collections;
+import java.util.ConcurrentModificationException;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.Hashtable;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.junit.Test;
+
+import com.google.common.collect.Lists;
+
+public class HashmapVsHashtableDifferenceUnitTest {
+
+    // null values
+    @Test(expected = NullPointerException.class)
+    public void givenHashtable_whenAddNullKey_thenNullPointerExceptionThrown() {
+        Hashtable<String, String> table = new Hashtable<String, String>();        
+        table.put(null, "value");
+    }
+    
+    @Test(expected = NullPointerException.class)
+    public void givenHashtable_whenAddNullValue_thenNullPointerExceptionThrown() {
+        Hashtable<String, String> table = new Hashtable<String, String>();        
+        table.put("key", null);
+    }
+    
+    @Test
+    public void givenHashmap_whenAddNullKeyAndValue_thenObjectAdded() {
+        HashMap<String, String> map = new HashMap<String, String>();
+        map.put(null, "value");
+        map.put("key1", null);
+        map.put("key2", null);
+        
+        assertEquals(3, map.size());
+    }
+    
+    // fail-fast iterator
+    @Test(expected = ConcurrentModificationException.class)
+    public void givenHashmap_whenModifyUnderlyingCollection_thenConcurrentModificationExceptionThrown() {
+        HashMap<String, String> map = new HashMap<String, String>();
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        map.put("key3", "value3");
+        
+        Iterator<String> iterator = map.keySet().iterator();
+        while(iterator.hasNext()){ 
+            iterator.next();
+            map.put("key4", "value4");
+        }        
+    }
+
+    @Test
+    public void givenHashtable_whenModifyUnderlyingCollection_thenItHasNoEffectOnIteratedCollection() {
+        Hashtable<String, String> table = new Hashtable<String, String>();        
+        table.put("key1", "value1");
+        table.put("key2", "value2");
+        
+        List<String> keysSelected = Lists.newArrayList(); 
+        Enumeration<String> keys = table.keys();
+        while (keys.hasMoreElements()) {
+            String key = keys.nextElement();
+            keysSelected.add(key);
+            
+            if (key.equals("key1")) {
+                table.put("key3", "value3");
+            }
+        }
+        
+        assertEquals(2, keysSelected.size());
+    }
+    
+    // synchronized map
+    @Test
+    public void givenHashmap_thenCreateSynchronizedMap() {
+        HashMap<String, String> map = new HashMap<String, String>();
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        map.put("key3", "value3");
+        
+        Set<Entry<String, String>> set = map.entrySet();
+        synchronized (map) {
+            Iterator<Entry<String, String>> it = set.iterator();
+            while(it.hasNext()) {
+                Map.Entry<String, String> elem = (Map.Entry<String, String>)it.next();
+             }            
+        }
+        
+        Map<String, String> syncMap = Collections.synchronizedMap(map);
+    }
+}

core-java-collections/src/test/java/org/baeldung/java/lists/ListJUnitTest.java

@@ -1,21 +0,0 @@
-package org.baeldung.java.lists;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-import java.util.Arrays;
-import java.util.List;
-
-public class ListJUnitTest {
-
-    private final List<String> list1 = Arrays.asList("1", "2", "3", "4");
-    private final List<String> list2 = Arrays.asList("1", "2", "3", "4");
-    private final List<String> list3 = Arrays.asList("1", "2", "4", "3");
-
-    @Test
-    public void whenTestingForEquality_ShouldBeEqual() throws Exception {
-        Assert.assertEquals(list1, list2);
-        Assert.assertNotSame(list1, list2);
-        Assert.assertNotEquals(list1, list3);
-    }
-}

core-java-concurrency-advanced/README.md

@@ -1,34 +1,24 @@
 =========
 
-## Core Java Concurrency Examples
+## Core Java Concurrency Advanced Examples
 
 ### Relevant Articles: 
-- [Guide To CompletableFuture](http://www.baeldung.com/java-completablefuture)
-- [A Guide to the Java ExecutorService](http://www.baeldung.com/java-executor-service-tutorial)
 - [Introduction to Thread Pools in Java](http://www.baeldung.com/thread-pool-java-and-guava)
-- [Guide to java.util.concurrent.Future](http://www.baeldung.com/java-future)
 - [Guide to CountDownLatch in Java](http://www.baeldung.com/java-countdown-latch)
 - [Guide to java.util.concurrent.Locks](http://www.baeldung.com/java-concurrent-locks)
 - [An Introduction to ThreadLocal in Java](http://www.baeldung.com/java-threadlocal)
-- [Difference Between Wait and Sleep in Java](http://www.baeldung.com/java-wait-and-sleep)
 - [LongAdder and LongAccumulator in Java](http://www.baeldung.com/java-longadder-and-longaccumulator)
 - [The Dining Philosophers Problem in Java](http://www.baeldung.com/java-dining-philoshophers)
 - [Guide to the Java Phaser](http://www.baeldung.com/java-phaser)
-- [Guide to Synchronized Keyword in Java](http://www.baeldung.com/java-synchronized)
 - [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)
-- [Overview of the java.util.concurrent](http://www.baeldung.com/java-util-concurrent)
 - [Semaphores in Java](http://www.baeldung.com/java-semaphore)
 - [Daemon Threads in Java](http://www.baeldung.com/java-daemon-thread)
-- [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)
-- [wait and notify() Methods in Java](http://www.baeldung.com/java-wait-notify)
 - [Priority-based Job Scheduling in Java](http://www.baeldung.com/java-priority-job-schedule)
-- [A Custom Spring SecurityConfigurer](http://www.baeldung.com/spring-security-custom-configurer)
-- [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)
 - [Brief Introduction to Java Thread.yield()](https://www.baeldung.com/java-thread-yield)
 - [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)
+- [The Thread.join() Method in Java](http://www.baeldung.com/java-thread-join)

core-java-concurrency-advanced/pom.xml

@@ -2,10 +2,10 @@
     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-concurrency</artifactId>
+    <artifactId>core-java-concurrency-advanced</artifactId>
     <version>0.1.0-SNAPSHOT</version>
     <packaging>jar</packaging>
-    <name>core-java-concurrency</name>
+    <name>core-java-concurrency-advanced</name>
 
     <parent>
         <groupId>com.baeldung</groupId>
@@ -47,10 +47,20 @@
             <version>${avaitility.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${jmh-core.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${jmh-generator-annprocess.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
-        <finalName>core-java-concurrency</finalName>
+        <finalName>core-java-concurrency-advanced</finalName>
         <resources>
             <resource>
                 <directory>src/main/resources</directory>
@@ -69,6 +79,8 @@
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
         <avaitility.version>1.7.0</avaitility.version>
+        <jmh-core.version>1.19</jmh-core.version>
+        <jmh-generator-annprocess.version>1.19</jmh-generator-annprocess.version>
     </properties>
 
 </project>

core-java-concurrency-advanced/src/main/java/com/baeldung/concurrent/atomic/SafeCounterWithLock.java

@@ -1,13 +1,13 @@
-package com.baeldung.concurrent.atomic;
-
-public class SafeCounterWithLock {
-    private volatile int counter;
-    
-    int getValue() {
-        return counter;
-    }
-    
-    synchronized void increment() {
-        counter++;
-    }
-}
+package com.baeldung.concurrent.atomic;
+
+public class SafeCounterWithLock {
+    private volatile int counter;
+    
+    int getValue() {
+        return counter;
+    }
+    
+    synchronized void increment() {
+        counter++;
+    }
+}

core-java-concurrency-advanced/src/main/java/com/baeldung/concurrent/atomic/SafeCounterWithoutLock.java

@@ -1,21 +1,21 @@
-package com.baeldung.concurrent.atomic;
-
-import java.util.concurrent.atomic.AtomicInteger;
-
-public class SafeCounterWithoutLock {
-    private final AtomicInteger counter = new AtomicInteger(0);
-    
-    int getValue() {
-        return counter.get();
-    }
-    
-    void increment() {
-        while(true) {
-            int existingValue = getValue();
-            int newValue = existingValue + 1;
-            if(counter.compareAndSet(existingValue, newValue)) {
-                return;
-            }
-        }
-    }
-}
+package com.baeldung.concurrent.atomic;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class SafeCounterWithoutLock {
+    private final AtomicInteger counter = new AtomicInteger(0);
+    
+    int getValue() {
+        return counter.get();
+    }
+    
+    void increment() {
+        while(true) {
+            int existingValue = getValue();
+            int newValue = existingValue + 1;
+            if(counter.compareAndSet(existingValue, newValue)) {
+                return;
+            }
+        }
+    }
+}

core-java-concurrency-advanced/src/main/java/com/baeldung/concurrent/atomic/UnsafeCounter.java

@@ -1,13 +1,13 @@
-package com.baeldung.concurrent.atomic;
-
-public class UnsafeCounter {
-    private int counter;
-    
-    int getValue() {
-        return counter;
-    }
-    
-    void increment() {
-        counter++;
-    }
-}
+package com.baeldung.concurrent.atomic;
+
+public class UnsafeCounter {
+    private int counter;
+    
+    int getValue() {
+        return counter;
+    }
+    
+    void increment() {
+        counter++;
+    }
+}