Merge branch 'master' into master

bootique/config.yml

@@ -0,0 +1,11 @@
+log:
+  level: warn
+  appenders:
+    - type: file
+      logFormat: '%c{20}: %m%n'
+      file: /home/logger.log
+
+jetty:
+  context: /hello
+  connector:
+    port: 10001

bootique/dependency-reduced-pom.xml

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <parent>
+    <artifactId>bootique-parent</artifactId>
+    <groupId>io.bootique.parent</groupId>
+    <version>0.12</version>
+  </parent>
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.baeldung.bootique</groupId>
+  <artifactId>bootique</artifactId>
+  <name>bootique</name>
+  <version>1.0-SNAPSHOT</version>
+  <url>http://maven.apache.org</url>
+  <build>
+    <plugins>
+      <plugin>
+        <artifactId>maven-shade-plugin</artifactId>
+      </plugin>
+    </plugins>
+  </build>
+  <dependencies>
+    <dependency>
+      <groupId>io.bootique</groupId>
+      <artifactId>bootique-test</artifactId>
+      <version>0.23</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>3.8.1</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+  <dependencyManagement>
+    <dependencies>
+      <dependency>
+        <groupId>io.bootique.bom</groupId>
+        <artifactId>bootique-bom</artifactId>
+        <version>0.23</version>
+        <type>pom</type>
+        <scope>import</scope>
+      </dependency>
+    </dependencies>
+  </dependencyManagement>
+  <properties>
+    <main.class>com.baeldung.bootique.App</main.class>
+  </properties>
+</project>
+

bootique/pom.xml

@@ -0,0 +1,66 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.baeldung.bootique</groupId>
+	<artifactId>bootique</artifactId>
+	<packaging>jar</packaging>
+	<version>1.0-SNAPSHOT</version>
+	<name>bootique</name>
+	<url>http://maven.apache.org</url>
+
+	<properties>
+		<main.class>com.baeldung.bootique.App</main.class>
+	</properties>
+
+	<parent>
+		<groupId>io.bootique.parent</groupId>
+		<artifactId>bootique-parent</artifactId>
+		<version>0.12</version>
+	</parent>
+
+	<dependencyManagement>
+		<dependencies>
+			<dependency>
+				<groupId>io.bootique.bom</groupId>
+				<artifactId>bootique-bom</artifactId>
+				<version>0.23</version>
+				<type>pom</type>
+				<scope>import</scope>
+			</dependency>
+		</dependencies>
+	</dependencyManagement>
+
+	<dependencies>
+		<dependency>
+			<groupId>io.bootique.jersey</groupId>
+			<artifactId>bootique-jersey</artifactId>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>io.bootique.logback</groupId>
+			<artifactId>bootique-logback</artifactId>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>io.bootique</groupId>
+			<artifactId>bootique-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>4.12</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-shade-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

bootique/src/main/java/com/baeldung/bootique/App.java

@@ -0,0 +1,41 @@
+package com.baeldung.bootique;
+
+import com.baeldung.bootique.module.ModuleBinder;
+import com.baeldung.bootique.router.IndexController;
+import com.baeldung.bootique.router.SaveController;
+import com.google.inject.Module;
+import io.bootique.Bootique;
+import io.bootique.jersey.JerseyModule;
+import io.bootique.log.BootLogger;
+
+import java.util.function.Supplier;
+
+public class App {
+
+    public static void main(String[] args) {
+        Module module = binder -> JerseyModule.extend(binder).addResource(IndexController.class)
+          .addResource(SaveController.class);
+        Bootique.app(args).module(module).module(ModuleBinder.class).bootLogger(new BootLogger() {
+            @Override
+            public void trace(Supplier<String> arg0) {
+                // ...
+            }
+
+            @Override
+            public void stdout(String arg0) {
+                // ...
+            }
+
+            @Override
+            public void stderr(String arg0, Throwable arg1) {
+                // ...
+            }
+
+            @Override
+            public void stderr(String arg0) {
+                // ...
+            }
+        }).autoLoadModules().exec();
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/module/ModuleBinder.java

@@ -0,0 +1,15 @@
+package com.baeldung.bootique.module;
+
+import com.baeldung.bootique.service.HelloService;
+import com.baeldung.bootique.service.impl.HelloServiceImpl;
+import com.google.inject.Binder;
+import com.google.inject.Module;
+
+public class ModuleBinder implements Module {
+
+    @Override
+    public void configure(Binder binder) {
+        binder.bind(HelloService.class).to(HelloServiceImpl.class);
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/module/ModuleProvider.java

@@ -0,0 +1,13 @@
+package com.baeldung.bootique.module;
+
+import com.google.inject.Module;
+import io.bootique.BQModuleProvider;
+
+public class ModuleProvider implements BQModuleProvider {
+
+    @Override
+    public Module module() {
+        return new ModuleBinder();
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/router/IndexController.java

@@ -0,0 +1,14 @@
+package com.baeldung.bootique.router;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+
+@Path("/")
+public class IndexController {
+
+    @GET
+    public String index() {
+        return "Hello, baeldung!";
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/router/SaveController.java

@@ -0,0 +1,20 @@
+package com.baeldung.bootique.router;
+
+import com.baeldung.bootique.service.HelloService;
+import com.google.inject.Inject;
+
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+
+@Path("/save")
+public class SaveController {
+
+    @Inject
+    HelloService helloService;
+
+    @POST
+    public String save() {
+        return "Data Saved!";
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/service/HelloService.java

@@ -0,0 +1,7 @@
+package com.baeldung.bootique.service;
+
+public interface HelloService {
+
+	boolean save();
+
+}

bootique/src/main/java/com/baeldung/bootique/service/impl/HelloServiceImpl.java

@@ -0,0 +1,12 @@
+package com.baeldung.bootique.service.impl;
+
+import com.baeldung.bootique.service.HelloService;
+
+public class HelloServiceImpl implements HelloService {
+
+	@Override
+	public boolean save() {
+		return true;
+	}
+
+}

bootique/src/main/resources/META-INF/services/io.bootique.BQModuleProvider

@@ -0,0 +1 @@
+com.baeldung.bootique.module.ModuleProvider

bootique/src/test/java/com/baeldung/bootique/AppTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.bootique;
+
+import com.baeldung.bootique.service.HelloService;
+import io.bootique.BQRuntime;
+import io.bootique.test.junit.BQDaemonTestFactory;
+import io.bootique.test.junit.BQTestFactory;
+import org.junit.Rule;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class AppTest {
+
+    @Rule
+    public BQTestFactory bqTestFactory = new BQTestFactory();
+
+    @Rule
+    public BQDaemonTestFactory bqDaemonTestFactory = new BQDaemonTestFactory();
+
+    @Test
+    public void givenService_expectBoolen() {
+        BQRuntime runtime = bqTestFactory.app("--server").autoLoadModules().createRuntime();
+        HelloService service = runtime.getInstance(HelloService.class);
+        assertEquals(true, service.save());
+    }
+
+}

core-java/hashcode/pom.xml

@@ -1,39 +0,0 @@
-<?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.hashcode</groupId>
-    <artifactId>hashcode</artifactId>
-    <version>1.0</version>
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <configuration>
-                    <source>1.8</source>
-                    <target>1.8</target>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
-    <dependencies>
-        <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <version>4.12</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-api</artifactId>
-            <version>1.7.25</version>
-        </dependency>
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-simple</artifactId>
-            <version>1.7.25</version>
-        </dependency>
-    </dependencies>
-</project>

core-java/hashcode/src/test/java/com/baeldung/application/ApplicationTest.java

@@ -1,30 +0,0 @@
-package com.baeldung.application;
-
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-import java.io.ByteArrayOutputStream;
-import java.io.PrintStream;
-import static org.junit.Assert.assertEquals;
-
-public class ApplicationTest {
-
-    private ByteArrayOutputStream outContent;
-
-    @Before
-    public void setUpPrintStreamInstance() throws Exception {
-        this.outContent = new ByteArrayOutputStream();
-        System.setOut(new PrintStream(outContent));
-    }
-
-    @After
-    public void tearDownByteArrayOutputStream() throws Exception {
-        outContent = null;
-    }
-
-    @Test
-    public void main_NoInputState_TextPrintedToConsole() throws Exception {
-        Application.main(new String[]{});
-        assertEquals("User found in the collection", outContent.toString());
-    }
-}

core-java/pom.xml

@@ -80,7 +80,11 @@
         </dependency>
 
         <!-- logging -->
-
+       <dependency>
+            <groupId>log4j</groupId>
+            <artifactId>log4j</artifactId>
+            <version>1.2.17</version>
+        </dependency>
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-api</artifactId>
@@ -391,7 +395,7 @@
         <logback.version>1.1.7</logback.version>
 
         <!-- util -->
-        <guava.version>21.0</guava.version>
+        <guava.version>22.0</guava.version>
         <commons-lang3.version>3.5</commons-lang3.version>
         <bouncycastle.version>1.55</bouncycastle.version>
         <commons-codec.version>1.10</commons-codec.version>

core-java/src/main/java/com/baeldung/concurrent/cyclicbarrier/CyclicBarrierDemo.java

@@ -15,14 +15,12 @@ public class CyclicBarrierDemo {
     private int NUM_PARTIAL_RESULTS;
     private int NUM_WORKERS;
 
-
     private void runSimulation(int numWorkers, int numberOfPartialResults) {
         NUM_PARTIAL_RESULTS = numberOfPartialResults;
         NUM_WORKERS = numWorkers;
 
         cyclicBarrier = new CyclicBarrier(NUM_WORKERS, new AggregatorThread());
-        System.out.println("Spawning " + NUM_WORKERS + " worker threads to compute "
+        System.out.println("Spawning " + NUM_WORKERS + " worker threads to compute " + NUM_PARTIAL_RESULTS + " partial results each");
-                + NUM_PARTIAL_RESULTS + " partial results each");
         for (int i = 0; i < NUM_WORKERS; i++) {
             Thread worker = new Thread(new NumberCruncherThread());
             worker.setName("Thread " + i);
@@ -38,8 +36,7 @@ public class CyclicBarrierDemo {
             List<Integer> partialResult = new ArrayList<>();
             for (int i = 0; i < NUM_PARTIAL_RESULTS; i++) {
                 Integer num = random.nextInt(10);
-                System.out.println(thisThreadName
+                System.out.println(thisThreadName + ": Crunching some numbers! Final result - " + num);
-                        + ": Crunching some numbers! Final result - " + num);
                 partialResult.add(num);
             }
             partialResults.add(partialResult);
@@ -57,13 +54,12 @@ public class CyclicBarrierDemo {
         @Override
         public void run() {
             String thisThreadName = Thread.currentThread().getName();
-            System.out.println(thisThreadName + ": Computing final sum of " + NUM_WORKERS
+            System.out.println(thisThreadName + ": Computing final sum of " + NUM_WORKERS + " workers, having " + NUM_PARTIAL_RESULTS + " results each.");
-                    + " workers, having " + NUM_PARTIAL_RESULTS + " results each.");
             int sum = 0;
             for (List<Integer> threadResult : partialResults) {
                 System.out.print("Adding ");
                 for (Integer partialResult : threadResult) {
-                    System.out.print(partialResult+" ");
+                    System.out.print(partialResult + " ");
                     sum += partialResult;
                 }
                 System.out.println();

core-java/src/main/java/com/baeldung/concurrent/diningphilosophers/Philosopher.java

@@ -15,7 +15,8 @@ public class Philosopher implements Runnable {
         Thread.sleep(((int) (Math.random() * 100)));
     }
 
-    @Override public void run() {
+    @Override
+    public void run() {
         try {
             while (true) {
                 doAction(System.nanoTime() + ": Thinking"); // thinking

core-java/src/main/java/com/baeldung/concurrent/executorservice/ExecutorServiceDemo.java

@@ -6,22 +6,22 @@ import java.util.concurrent.TimeUnit;
 
 public class ExecutorServiceDemo {
 
-	ExecutorService executor = Executors.newFixedThreadPool(10);
+    ExecutorService executor = Executors.newFixedThreadPool(10);
 
-	public void execute() {
+    public void execute() {
 
-		executor.submit(() -> {
+        executor.submit(() -> {
-			new Task();
+            new Task();
-		});
+        });
 
-		executor.shutdown();
+        executor.shutdown();
-		executor.shutdownNow();
+        executor.shutdownNow();
-		try {
+        try {
-			executor.awaitTermination(20l, TimeUnit.NANOSECONDS);
+            executor.awaitTermination(20l, TimeUnit.NANOSECONDS);
-		} catch (InterruptedException e) {
+        } catch (InterruptedException e) {
-			e.printStackTrace();
+            e.printStackTrace();
-		}
+        }
 
-	}
+    }
 
 }

core-java/src/main/java/com/baeldung/concurrent/future/FutureDemo.java

@@ -9,36 +9,36 @@ import java.util.concurrent.TimeoutException;
 
 public class FutureDemo {
 
-	public String invoke() {
+    public String invoke() {
 
-		String str = null;
+        String str = null;
 
-		ExecutorService executorService = Executors.newFixedThreadPool(10);
+        ExecutorService executorService = Executors.newFixedThreadPool(10);
 
-		Future<String> future = executorService.submit(() -> {
+        Future<String> future = executorService.submit(() -> {
-			// Task
+            // Task
-			Thread.sleep(10000l);
+            Thread.sleep(10000l);
-			return "Hellow world";
+            return "Hellow world";
-		});
+        });
 
-		future.cancel(false);
+        future.cancel(false);
 
-		try {
+        try {
-			future.get(20, TimeUnit.SECONDS);
+            future.get(20, TimeUnit.SECONDS);
-		} catch (InterruptedException | ExecutionException | TimeoutException e1) {
+        } catch (InterruptedException | ExecutionException | TimeoutException e1) {
-			e1.printStackTrace();
+            e1.printStackTrace();
-		}
+        }
 
-		if (future.isDone() && !future.isCancelled()) {
+        if (future.isDone() && !future.isCancelled()) {
-			try {
+            try {
-				str = future.get();
+                str = future.get();
-			} catch (InterruptedException | ExecutionException e) {
+            } catch (InterruptedException | ExecutionException e) {
-				e.printStackTrace();
+                e.printStackTrace();
-			}
+            }
-		}
+        }
 
-		return str;
+        return str;
 
-	}
+    }
 
 }

core-java/src/main/java/com/baeldung/concurrent/threadfactory/BaeldungThreadFactory.java

@@ -4,20 +4,20 @@ import java.util.concurrent.ThreadFactory;
 
 public class BaeldungThreadFactory implements ThreadFactory {
 
-	private int threadId;
+    private int threadId;
-	private String name;
+    private String name;
 
-	public BaeldungThreadFactory(String name) {
+    public BaeldungThreadFactory(String name) {
-		threadId = 1;
+        threadId = 1;
-		this.name = name;
+        this.name = name;
-	}
+    }
 
-	@Override
+    @Override
-	public Thread newThread(Runnable r) {
+    public Thread newThread(Runnable r) {
-		Thread t = new Thread(r, name + "-Thread_" + threadId);
+        Thread t = new Thread(r, name + "-Thread_" + threadId);
-		System.out.println("created new thread with id : " + threadId + " and name : " + t.getName());
+        System.out.println("created new thread with id : " + threadId + " and name : " + t.getName());
-		threadId++;
+        threadId++;
-		return t;
+        return t;
-	}
+    }
 
 }

core-java/src/main/java/com/baeldung/concurrent/threadfactory/Task.java

@@ -2,9 +2,9 @@ package com.baeldung.concurrent.threadfactory;
 
 public class Task implements Runnable {
 
-	@Override
+    @Override
-	public void run() {
+    public void run() {
-		// task details
+        // task details
-	}
+    }
-	
+
 }

core-java/src/main/java/com/baeldung/designpatterns/adapter/AdapterPatternDriver.java

@@ -0,0 +1,13 @@
+package com.baeldung.designpatterns.adapter;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class AdapterPatternDriver {
+    
+    public static void main(String args[]) {
+        LuxuryCarsSpeedAdapter luxuryCars = new LuxuryCarsSpeedAdapterImpl();
+        LOG.info("Bugatti Veyron Super Sport's top speed is " + luxuryCars.bugattiVeyronInKMPH() + " Kmph.");
+        LOG.info("McLaren F1 top speed is " + luxuryCars.mcLarenInKMPH() + " Kmph.");
+        LOG.info("Aston Martin One-77 top speed is " + luxuryCars.astonMartinInKMPH() + " Kmph.");
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/adapter/LuxuryCarsSpeed.java

@@ -0,0 +1,15 @@
+package com.baeldung.designpatterns.adapter;
+
+public class LuxuryCarsSpeed {
+    public double bugattiVeyronInMPH() {
+        return 268;
+    }
+    
+    public double mcLarenInMPH() {
+        return 241;
+    }
+    
+    public double astonMartinInMPH() {
+        return 220;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/adapter/LuxuryCarsSpeedAdapter.java

@@ -0,0 +1,7 @@
+package com.baeldung.designpatterns.adapter;
+
+public interface LuxuryCarsSpeedAdapter {
+    public double bugattiVeyronInKMPH();
+    public double mcLarenInKMPH();
+    public double astonMartinInKMPH();
+}

core-java/src/main/java/com/baeldung/designpatterns/adapter/LuxuryCarsSpeedAdapterImpl.java

@@ -0,0 +1,26 @@
+package com.baeldung.designpatterns.adapter;
+
+public class LuxuryCarsSpeedAdapterImpl extends LuxuryCarsSpeed implements LuxuryCarsSpeedAdapter {
+
+    @Override
+    public double bugattiVeyronInKMPH() {
+        double mph = super.bugattiVeyronInMPH();
+        return convertMPHtoKMPH(mph);
+    }
+
+    @Override
+    public double mcLarenInKMPH() {
+        double mph = super.mcLarenInMPH();
+        return convertMPHtoKMPH(mph);
+    }
+
+    @Override
+    public double astonMartinInKMPH() {
+        double mph = super.astonMartinInMPH();
+        return convertMPHtoKMPH(mph);
+    }
+
+    private double convertMPHtoKMPH(double mph) {
+        return mph * 1.60934;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Blue.java

@@ -0,0 +1,12 @@
+package com.baeldung.designpatterns.bridge;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class Blue implements Color {
+
+    @Override
+    public void fillColor() { 
+        LOG.info("Color : Blue");
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/BridgePatternDriver.java

@@ -0,0 +1,14 @@
+package com.baeldung.designpatterns.bridge;
+
+public class BridgePatternDriver {
+
+    public static void main(String[] args) {
+        //a square with red color
+        Shape square = new Square(new Red());
+        square.drawShape();
+        
+        //a triangle with blue color
+        Shape triangle = new Triangle(new Blue());
+        triangle.drawShape();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Color.java

@@ -0,0 +1,5 @@
+package com.baeldung.designpatterns.bridge;
+
+public interface Color {
+    public void fillColor();
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Red.java

@@ -0,0 +1,12 @@
+package com.baeldung.designpatterns.bridge;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class Red implements Color {
+
+    @Override
+    public void fillColor() {
+        LOG.info("Color : Red");
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Shape.java

@@ -0,0 +1,11 @@
+package com.baeldung.designpatterns.bridge;
+
+public abstract class Shape {
+    protected Color color;
+    
+    public Shape(Color color) {
+        this.color = color;
+    }
+    
+    abstract public void drawShape();
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Square.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.bridge;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class Square extends Shape {
+
+    public Square(Color color) {
+        super(color);
+    }
+
+    @Override
+    public void drawShape() {
+        LOG.info("Square drawn. ");
+        color.fillColor();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Triangle.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.bridge;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class Triangle extends Shape {
+
+    public Triangle(Color color) {
+        super(color);
+    }
+
+    @Override
+    public void drawShape() {
+        LOG.info("Triangle drawn. ");
+        color.fillColor();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/BubbleLights.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.decorator;
+
+public class BubbleLights extends TreeDecorator {
+
+    public BubbleLights(ChristmasTree tree) {
+        super(tree);
+    }
+    
+    public String decorate() {
+        return super.decorate() + decorateWithBubbleLights();
+    }
+    
+    private String decorateWithBubbleLights() {
+        return " with Bubble Lights";
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/ChristmasTree.java

@@ -0,0 +1,5 @@
+package com.baeldung.designpatterns.decorator;
+
+public interface ChristmasTree {
+    public String decorate();
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/ChristmasTreeImpl.java

@@ -0,0 +1,10 @@
+package com.baeldung.designpatterns.decorator;
+
+public class ChristmasTreeImpl implements ChristmasTree {
+
+    @Override
+    public String decorate() {
+        return "Christmas tree";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/DecoratorPatternDriver.java

@@ -0,0 +1,20 @@
+package com.baeldung.designpatterns.decorator;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class DecoratorPatternDriver {
+
+    public static void main(String[] args) {
+        //christmas tree with just one Garland
+        ChristmasTree tree1 = new Garland(new ChristmasTreeImpl());
+        LOG.info(tree1.decorate());
+        
+        //christmas tree with two Garlands and one Bubble lights
+        ChristmasTree tree2 = new BubbleLights(new Garland(
+          new Garland(new ChristmasTreeImpl()))
+        );
+        LOG.info(tree2.decorate());
+        
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/Garland.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.decorator;
+
+public class Garland extends TreeDecorator {
+
+    public Garland(ChristmasTree tree) {
+        super(tree);
+    }
+    
+    public String decorate() {
+        return super.decorate() + decorateWithGarland();
+    }
+
+    private String decorateWithGarland() {
+        return " with Garland";
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/TreeDecorator.java

@@ -0,0 +1,15 @@
+package com.baeldung.designpatterns.decorator;
+
+public abstract class TreeDecorator implements ChristmasTree {
+    private ChristmasTree tree;
+    
+    public TreeDecorator(ChristmasTree tree) {
+        this.tree = tree;
+    }
+    
+    @Override
+    public String decorate() {
+        return tree.decorate();
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/proxy/ExpensiveObject.java

@@ -0,0 +1,5 @@
+package com.baeldung.designpatterns.proxy;
+
+public interface ExpensiveObject {
+    public void process();
+}

core-java/src/main/java/com/baeldung/designpatterns/proxy/ExpensiveObjectImpl.java

@@ -0,0 +1,20 @@
+package com.baeldung.designpatterns.proxy;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;;
+
+public class ExpensiveObjectImpl implements ExpensiveObject {
+
+    public ExpensiveObjectImpl() {
+        heavyInitialConfiguration();
+    }
+    
+    @Override
+    public void process() {
+        LOG.info("processing complete.");
+    }
+    
+    private void heavyInitialConfiguration() {
+        LOG.info("Loading initial configuration...");
+    }
+    
+}

core-java/src/main/java/com/baeldung/designpatterns/proxy/ExpensiveObjectProxy.java

@@ -0,0 +1,13 @@
+package com.baeldung.designpatterns.proxy;
+
+public class ExpensiveObjectProxy implements ExpensiveObject{
+    private static ExpensiveObject object;
+
+    @Override
+    public void process() {
+        if(object == null) {
+            object = new ExpensiveObjectImpl();
+        }
+        object.process();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/proxy/ProxyPatternDriver.java

@@ -0,0 +1,9 @@
+package com.baeldung.designpatterns.proxy;
+
+public class ProxyPatternDriver {
+    public static void main(String[] args) {
+        ExpensiveObject object = new ExpensiveObjectProxy();
+        object.process();
+        object.process();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/singleton/ClassSingleton.java

@@ -0,0 +1,28 @@
+package com.baeldung.designpatterns.singleton;
+
+public class ClassSingleton {
+
+    private static ClassSingleton INSTANCE;
+    private String info = "Initial class info";
+    
+    private ClassSingleton(){        
+    }
+    
+    public static ClassSingleton getInstance(){
+        if(INSTANCE == null){
+            INSTANCE = new ClassSingleton();
+        }
+        
+        return INSTANCE;
+    }
+    
+    // getters and setters
+    
+    public String getInfo() {
+        return info;
+    }
+    
+    public void setInfo(String info) {
+        this.info = info;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/singleton/EnumSingleton.java

@@ -0,0 +1,26 @@
+package com.baeldung.designpatterns.singleton;
+
+public enum EnumSingleton {
+    
+    INSTANCE("Initial enum info"); //Name of the single instance
+    
+    private String info;
+    
+    private EnumSingleton(String info) {
+        this.info = info;
+    }
+    
+    public EnumSingleton getInstance(){
+        return INSTANCE;
+    }
+    
+    //getters and setters
+
+    public String getInfo() {
+        return info;
+    }
+
+    public void setInfo(String info) {
+        this.info = info;
+    }    
+}

core-java/src/main/java/com/baeldung/designpatterns/singleton/Sandbox.java

@@ -0,0 +1,32 @@
+package com.baeldung.designpatterns.singleton;
+
+public class Sandbox {
+
+    public static void main(String[] args) {
+        
+        //Class singleton
+        
+        ClassSingleton classSingleton1 = ClassSingleton.getInstance();
+        //OurSingleton object1 = new OurSingleton(); // The constructor OurSingleton() is not visible
+        
+        System.out.println(classSingleton1.getInfo()); //Initial class info
+        
+        ClassSingleton classSingleton2 = ClassSingleton.getInstance();
+        classSingleton2.setInfo("New class info");
+        
+        System.out.println(classSingleton1.getInfo()); //New class info
+        System.out.println(classSingleton2.getInfo()); //New class info
+        
+        //Enum singleton
+        
+        EnumSingleton enumSingleton1 = EnumSingleton.INSTANCE.getInstance();
+        
+        System.out.println(enumSingleton1.getInfo()); //Initial enum info
+        
+        EnumSingleton enumSingleton2 = EnumSingleton.INSTANCE.getInstance();
+        enumSingleton2.setInfo("New enum info");
+        
+        System.out.println(enumSingleton1.getInfo()); //New enum info
+        System.out.println(enumSingleton2.getInfo()); //New enum info
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/util/LogerUtil.java

@@ -0,0 +1,35 @@
+package com.baeldung.designpatterns.util;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Properties;
+
+import org.apache.log4j.Logger;
+import org.apache.log4j.PropertyConfigurator;
+
+public class LogerUtil {
+
+    public final static Logger LOG = Logger.getLogger("GLOBAL");
+    
+    static {
+    	configuration();
+    }
+    
+    private static void configuration() {
+    	Properties props = new Properties();
+    	try {
+			props.load(
+			  new BufferedReader(
+			    new InputStreamReader(
+			      LogerUtil.class.getResourceAsStream("/log4jstructuraldp.properties")
+			    )
+			  )
+			);
+		} catch (IOException e) {
+			System.out.println("log4jstructuraldp.properties file not configured properly");
+			System.exit(0);
+		}
+    	PropertyConfigurator.configure(props);
+    }
+}

core-java/src/main/java/com/baeldung/filesystem/jndi/LookupFSJNDI.java

@@ -14,26 +14,25 @@ public class LookupFSJNDI {
         super();
         init();
     }
-    
+
     private void init() throws NamingException {
         Hashtable<String, String> env = new Hashtable<String, String>();
-        
+
-        env.put (Context.INITIAL_CONTEXT_FACTORY,
+        env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.fscontext.RefFSContextFactory");
-          "com.sun.jndi.fscontext.RefFSContextFactory");
         // URI to namespace (actual directory)
         env.put(Context.PROVIDER_URL, "file:./src/test/resources");
-        
+
         ctx = new InitialContext(env);
     }
 
     public InitialContext getCtx() {
         return ctx;
     }
-    
+
     public File getFile(String fileName) {
         File file;
         try {
-            file = (File)getCtx().lookup(fileName);
+            file = (File) getCtx().lookup(fileName);
         } catch (NamingException e) {
             file = null;
         }

core-java/src/main/java/com/baeldung/hashcode/entities/User.java

@@ -1,4 +1,4 @@
-package com.baeldung.entities;
+package com.baeldung.hashcode.entities;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -18,13 +18,16 @@ public class User {
 
     @Override
     public boolean equals(Object o) {
-        if (this == o) return true;
+        if (this == o)
-        if (o == null) return false;
+            return true;
-        if (this.getClass() != o.getClass()) return false;
+        if (o == null)
+            return false;
+        if (this.getClass() != o.getClass())
+            return false;
         User user = (User) o;
         return id != user.id && (!name.equals(user.name) && !email.equals(user.email));
     }
-    	
+
     @Override
     public int hashCode() {
         int hash = 7;

core-java/src/main/java/com/baeldung/jmx/JMXTutorialMainlauncher.java

@@ -10,7 +10,6 @@ public class JMXTutorialMainlauncher {
 
     private static final Logger LOG = LoggerFactory.getLogger(JMXTutorialMainlauncher.class);
 
-
     public static void main(String[] args) {
         // TODO Auto-generated method stub
 

core-java/src/main/java/com/baeldung/socket/EchoClient.java

@@ -8,9 +8,8 @@ import java.net.*;
 
 public class EchoClient {
 
-
     private static final Logger LOG = LoggerFactory.getLogger(EchoClient.class);
-    
+
     private Socket clientSocket;
     private PrintWriter out;
     private BufferedReader in;

core-java/src/main/java/com/baeldung/stream/InfiniteStreams.java

@@ -1,6 +1,5 @@
 package com.baeldung.stream;
 
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 

core-java/src/main/java/com/baeldung/string/StringHelper.java

@@ -12,15 +12,10 @@ class StringHelper {
     }
 
     static String removeLastCharOptional(String s) {
-        return Optional.ofNullable(s)
+        return Optional.ofNullable(s).filter(str -> str.length() != 0).map(str -> str.substring(0, str.length() - 1)).orElse(s);
-            .filter(str -> str.length() != 0)
-            .map(str -> str.substring(0, str.length() - 1))
-            .orElse(s);
     }
 
     static String removeLastCharRegexOptional(String s) {
-        return Optional.ofNullable(s)
+        return Optional.ofNullable(s).map(str -> str.replaceAll(".$", "")).orElse(s);
-            .map(str -> str.replaceAll(".$", ""))
-            .orElse(s);
     }
 }

core-java/src/main/java/com/baeldung/stringtokenizer/MyTokenizer.java

@@ -25,11 +25,7 @@ public class MyTokenizer {
     }
 
     public List<String> getTokensWithCollection(String str) {
-        return Collections
+        return Collections.list(new StringTokenizer(str, ",")).stream().map(token -> (String) token).collect(Collectors.toList());
-          .list(new StringTokenizer(str, ","))
-          .stream()
-          .map(token -> (String) token)
-          .collect(Collectors.toList());
     }
 
     public List<String> getTokensFromFile(String path, String delim) {

core-java/src/main/java/com/baeldung/temporaladjuster/CustomTemporalAdjuster.java

@@ -11,12 +11,12 @@ public class CustomTemporalAdjuster implements TemporalAdjuster {
     @Override
     public Temporal adjustInto(Temporal temporal) {
         switch (DayOfWeek.of(temporal.get(ChronoField.DAY_OF_WEEK))) {
-            case FRIDAY:
+        case FRIDAY:
-                return temporal.plus(3, ChronoUnit.DAYS);
+            return temporal.plus(3, ChronoUnit.DAYS);
-            case SATURDAY:
+        case SATURDAY:
-                return temporal.plus(2, ChronoUnit.DAYS);
+            return temporal.plus(2, ChronoUnit.DAYS);
-            default:
+        default:
-                return temporal.plus(1, ChronoUnit.DAYS);
+            return temporal.plus(1, ChronoUnit.DAYS);
         }
     }
 }

core-java/src/main/java/com/baeldung/transferqueue/Consumer.java

@@ -9,7 +9,6 @@ import java.util.concurrent.atomic.AtomicInteger;
 public class Consumer implements Runnable {
     private static final Logger LOG = LoggerFactory.getLogger(Consumer.class);
 
-    
     private final TransferQueue<String> transferQueue;
     private final String name;
     private final int numberOfMessagesToConsume;

core-java/src/main/resources/log4jstructuraldp.properties

@@ -0,0 +1,9 @@
+
+# Root logger 
+log4j.rootLogger=INFO, file, stdout
+
+# Write to console
+log4j.appender.stdout=org.apache.log4j.ConsoleAppender
+log4j.appender.stdout.Target=System.out
+log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
+log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

core-java/src/test/java/com/baeldung/concurrent/accumulator/LongAccumulatorUnitTest.java

@@ -15,28 +15,24 @@ public class LongAccumulatorUnitTest {
 
     @Test
     public void givenLongAccumulator_whenApplyActionOnItFromMultipleThrads_thenShouldProduceProperResult() throws InterruptedException {
-        //given
+        // given
         ExecutorService executorService = Executors.newFixedThreadPool(8);
         LongBinaryOperator sum = Long::sum;
         LongAccumulator accumulator = new LongAccumulator(sum, 0L);
         int numberOfThreads = 4;
         int numberOfIncrements = 100;
 
-        //when
+        // when
-        Runnable accumulateAction = () -> IntStream
+        Runnable accumulateAction = () -> IntStream.rangeClosed(0, numberOfIncrements).forEach(accumulator::accumulate);
-          .rangeClosed(0, numberOfIncrements)
-          .forEach(accumulator::accumulate);
 
         for (int i = 0; i < numberOfThreads; i++) {
             executorService.execute(accumulateAction);
         }
 
-
+        // then
-        //then
         executorService.awaitTermination(500, TimeUnit.MILLISECONDS);
         executorService.shutdown();
         assertEquals(accumulator.get(), 20200);
 
-
     }
 }

core-java/src/test/java/com/baeldung/designpatterns/AdapterPatternIntegrationTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.designpatterns;
+
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import com.baeldung.designpatterns.adapter.LuxuryCarsSpeedAdapter;
+import com.baeldung.designpatterns.adapter.LuxuryCarsSpeedAdapterImpl;
+
+public class AdapterPatternIntegrationTest {
+    @Test
+    public void givenLuxuryCarsAdapter_WhenConvertingMPHToKMPH_thenSuccessfullyConverted() {
+        LuxuryCarsSpeedAdapter luxuryCars = new LuxuryCarsSpeedAdapterImpl();
+        assertEquals(luxuryCars.bugattiVeyronInKMPH(), 431.30312, 0.00001);
+        assertEquals(luxuryCars.mcLarenInKMPH(), 387.85094, 0.00001);
+        assertEquals(luxuryCars.astonMartinInKMPH(), 354.0548, 0.00001);
+    }
+}
+

core-java/src/test/java/com/baeldung/designpatterns/BridgePatternIntegrationTest.java

@@ -0,0 +1,52 @@
+package com.baeldung.designpatterns;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.List;
+
+import org.apache.log4j.spi.LoggingEvent;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.designpatterns.bridge.Blue;
+import com.baeldung.designpatterns.bridge.Red;
+import com.baeldung.designpatterns.bridge.Shape;
+import com.baeldung.designpatterns.bridge.Square;
+import com.baeldung.designpatterns.bridge.Triangle;
+
+public class BridgePatternIntegrationTest {
+    public static TestAppenderDP appender;
+    
+    @Before
+    public void setUp() {
+        appender = new TestAppenderDP();
+        LOG.addAppender(appender);
+    }
+    
+    @Test
+    public void whenBridgePatternInvoked_thenConfigSuccess() {
+        //a square with red color
+        Shape square = new Square(new Red());
+        square.drawShape();
+        
+        //a triangle with blue color
+        Shape triangle = new Triangle(new Blue());
+        triangle.drawShape();
+
+        final List<LoggingEvent> log = appender.getLog();
+        
+        assertThat((String) log.get(0).getMessage(), is("Square drawn. "));
+        assertThat((String) log.get(1).getMessage(), is("Color : Red"));
+        assertThat((String) log.get(2).getMessage(), is("Triangle drawn. "));
+        assertThat((String) log.get(3).getMessage(), is("Color : Blue"));
+    }
+    
+    @After
+    public void tearDown() {
+        LOG.removeAppender(appender);
+    }
+}
+

core-java/src/test/java/com/baeldung/designpatterns/DecoratorPatternIntegrationTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.designpatterns;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import com.baeldung.designpatterns.decorator.BubbleLights;
+import com.baeldung.designpatterns.decorator.ChristmasTree;
+import com.baeldung.designpatterns.decorator.ChristmasTreeImpl;
+import com.baeldung.designpatterns.decorator.Garland;
+
+public class DecoratorPatternIntegrationTest {
+    private ChristmasTree tree;
+    
+    @Test
+    public void givenDecoratorPattern_WhenDecoratorsInjectedAtRuntime_thenConfigSuccess() {
+        //christmas tree with just one Garland
+        tree = new Garland(new ChristmasTreeImpl());
+        assertEquals(tree.decorate(), "Christmas tree with Garland");
+        
+        //christmas tree with two Garlands and one Bubble lights
+        tree = new BubbleLights(new Garland(
+          new Garland(new ChristmasTreeImpl()))
+        );
+        assertEquals(tree.decorate(), "Christmas tree with Garland with Garland with Bubble Lights");
+    }
+}
+

core-java/src/test/java/com/baeldung/designpatterns/ProxyPatternIntegrationTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.designpatterns;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.List;
+
+import org.apache.log4j.spi.LoggingEvent;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.designpatterns.proxy.ExpensiveObject;
+import com.baeldung.designpatterns.proxy.ExpensiveObjectProxy;
+
+public class ProxyPatternIntegrationTest {
+    public static TestAppenderDP appender;
+    
+    @Before
+    public void setUp() {
+        appender = new TestAppenderDP();
+        LOG.addAppender(appender);
+    }
+    
+    @Test
+    public void givenExpensiveObjectProxy_WhenObjectInitialized_thenInitializedOnlyOnce() {
+        ExpensiveObject object = new ExpensiveObjectProxy();
+        object.process();
+        object.process();
+
+        final List<LoggingEvent> log = appender.getLog();
+        
+        assertThat((String) log.get(0).getMessage(), is("Loading initial configuration..."));
+        assertThat((String) log.get(1).getMessage(), is("processing complete."));
+        assertThat((String) log.get(2).getMessage(), is("processing complete."));
+    }
+    
+    @After
+    public void tearDown() {
+        LOG.removeAppender(appender);
+    }
+}
+

core-java/src/test/java/com/baeldung/designpatterns/TestAppenderDP.java

@@ -0,0 +1,29 @@
+package com.baeldung.designpatterns;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.log4j.AppenderSkeleton;
+import org.apache.log4j.spi.LoggingEvent;
+
+public class TestAppenderDP extends AppenderSkeleton {
+    private final List<LoggingEvent> log = new ArrayList<LoggingEvent>();
+
+    @Override
+    public boolean requiresLayout() {
+        return false;
+    }
+
+    @Override
+    protected void append(final LoggingEvent loggingEvent) {
+        log.add(loggingEvent);
+    }
+
+    @Override
+    public void close() {
+    }
+
+    public List<LoggingEvent> getLog() {
+        return new ArrayList<LoggingEvent>(log);
+    }
+}

core-java/src/test/java/com/baeldung/hashcode/application/ApplicationTest.java

@@ -1,12 +1,17 @@
-package com.baeldung.application;
+package com.baeldung.hashcode.application;
+
+import com.baeldung.hashcode.entities.User;
+import org.junit.Test;
 
-import com.baeldung.entities.User;
 import java.util.HashMap;
 import java.util.Map;
 
-public class Application {
+import static org.junit.Assert.assertTrue;
 
-    public static void main(String[] args) {
+public class ApplicationTest {
+
+    @Test
+    public void main_NoInputState_TextPrintedToConsole() throws Exception {
         Map<User, User> users = new HashMap<>();
         User user1 = new User(1L, "John", "john@domain.com");
         User user2 = new User(2L, "Jennifer", "jennifer@domain.com");
@@ -16,8 +21,6 @@ public class Application {
         users.put(user2, user2);
         users.put(user3, user3);
 
-        if (users.containsKey(user1)) {
+        assertTrue(users.containsKey(user1));
-            System.out.print("User found in the collection");
-        }
     }
-}
+}

core-java/src/test/java/com/baeldung/hashcode/entities/UserTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.entities;
+package com.baeldung.hashcode.entities;
 
 import org.junit.After;
 import org.junit.Assert;
@@ -23,7 +23,7 @@ public class UserTest {
     }
 
     @Test
-    public void equals_EqualUserInstance_TrueAssertion(){
+    public void equals_EqualUserInstance_TrueAssertion() {
         Assert.assertTrue(user.equals(comparisonUser));
     }
 

core-java/src/test/java/com/baeldung/java8/lambda/exceptions/LambdaExceptionWrappersUnitTest.java

@@ -15,7 +15,6 @@ public class LambdaExceptionWrappersUnitTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(LambdaExceptionWrappersUnitTest.class);
 
-
     private List<Integer> integers;
 
     @Before

core-java/src/test/java/com/baeldung/list/listoflist/ListOfListsUnitTest.java

@@ -29,12 +29,9 @@ public class ListOfListsUnitTest {
 
     @Test
     public void givenListOfLists_thenCheckNames() {
-        assertEquals("Pen 1", ((Pen) listOfLists.get(0)
+        assertEquals("Pen 1", ((Pen) listOfLists.get(0).get(0)).getName());
-          .get(0)).getName());
+        assertEquals("Pencil 1", ((Pencil) listOfLists.get(1).get(0)).getName());
-        assertEquals("Pencil 1", ((Pencil) listOfLists.get(1)
+        assertEquals("Rubber 1", ((Rubber) listOfLists.get(2).get(0)).getName());
-          .get(0)).getName());
-        assertEquals("Rubber 1", ((Rubber) listOfLists.get(2)
-          .get(0)).getName());
     }
 
     @SuppressWarnings("unchecked")
@@ -43,11 +40,9 @@ public class ListOfListsUnitTest {
 
         ((ArrayList<Pencil>) listOfLists.get(1)).remove(0);
         listOfLists.remove(1);
-        assertEquals("Rubber 1", ((Rubber) listOfLists.get(1)
+        assertEquals("Rubber 1", ((Rubber) listOfLists.get(1).get(0)).getName());
-          .get(0)).getName());
         listOfLists.remove(0);
-        assertEquals("Rubber 1", ((Rubber) listOfLists.get(0)
+        assertEquals("Rubber 1", ((Rubber) listOfLists.get(0).get(0)).getName());
-          .get(0)).getName());
     }
 
     @Test
@@ -67,11 +62,8 @@ public class ListOfListsUnitTest {
         list.add(pencils);
         list.add(rubbers);
 
-        assertEquals("Pen 1", ((Pen) list.get(0)
+        assertEquals("Pen 1", ((Pen) list.get(0).get(0)).getName());
-          .get(0)).getName());
+        assertEquals("Pencil 1", ((Pencil) list.get(1).get(0)).getName());
-        assertEquals("Pencil 1", ((Pencil) list.get(1)
+        assertEquals("Rubber 1", ((Rubber) list.get(2).get(0)).getName());
-          .get(0)).getName());
-        assertEquals("Rubber 1", ((Rubber) list.get(2)
-          .get(0)).getName());
     }
 }

core-java/src/test/java/com/baeldung/money/JavaMoneyUnitManualTest.java

@@ -1,190 +1,190 @@
-package com.baeldung.money;
+package com.baeldung.money;
-
+
-import org.javamoney.moneta.FastMoney;
+import org.javamoney.moneta.FastMoney;
-import org.javamoney.moneta.Money;
+import org.javamoney.moneta.Money;
-import org.javamoney.moneta.format.CurrencyStyle;
+import org.javamoney.moneta.format.CurrencyStyle;
-import org.junit.Ignore;
+import org.junit.Ignore;
-import org.junit.Test;
+import org.junit.Test;
-
+
-import javax.money.CurrencyUnit;
+import javax.money.CurrencyUnit;
-import javax.money.Monetary;
+import javax.money.Monetary;
-import javax.money.MonetaryAmount;
+import javax.money.MonetaryAmount;
-import javax.money.UnknownCurrencyException;
+import javax.money.UnknownCurrencyException;
-import javax.money.convert.CurrencyConversion;
+import javax.money.convert.CurrencyConversion;
-import javax.money.convert.MonetaryConversions;
+import javax.money.convert.MonetaryConversions;
-import javax.money.format.AmountFormatQueryBuilder;
+import javax.money.format.AmountFormatQueryBuilder;
-import javax.money.format.MonetaryAmountFormat;
+import javax.money.format.MonetaryAmountFormat;
-import javax.money.format.MonetaryFormats;
+import javax.money.format.MonetaryFormats;
-import java.util.Arrays;
+import java.util.Arrays;
-import java.util.List;
+import java.util.List;
-import java.util.Locale;
+import java.util.Locale;
-
+
-import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.fail;
-
+
-public class JavaMoneyUnitTest {
+public class JavaMoneyUnitManualTest {
-
+
-    @Test
+    @Test
-    public void givenCurrencyCode_whenString_thanExist() {
+    public void givenCurrencyCode_whenString_thanExist() {
-        CurrencyUnit usd = Monetary.getCurrency("USD");
+        CurrencyUnit usd = Monetary.getCurrency("USD");
-
+
-        assertNotNull(usd);
+        assertNotNull(usd);
-        assertEquals(usd.getCurrencyCode(), "USD");
+        assertEquals(usd.getCurrencyCode(), "USD");
-        assertEquals(usd.getNumericCode(), 840);
+        assertEquals(usd.getNumericCode(), 840);
-        assertEquals(usd.getDefaultFractionDigits(), 2);
+        assertEquals(usd.getDefaultFractionDigits(), 2);
-    }
+    }
-
+
-    @Test(expected = UnknownCurrencyException.class)
+    @Test(expected = UnknownCurrencyException.class)
-    public void givenCurrencyCode_whenNoExist_thanThrowsError() {
+    public void givenCurrencyCode_whenNoExist_thanThrowsError() {
-        Monetary.getCurrency("AAA");
+        Monetary.getCurrency("AAA");
-    }
+    }
-
+
-    @Test
+    @Test
-    public void givenAmounts_whenStringified_thanEquals() {
+    public void givenAmounts_whenStringified_thanEquals() {
-        CurrencyUnit usd = Monetary.getCurrency("USD");
+        CurrencyUnit usd = Monetary.getCurrency("USD");
-        MonetaryAmount fstAmtUSD = Monetary
+        MonetaryAmount fstAmtUSD = Monetary
-          .getDefaultAmountFactory()
+          .getDefaultAmountFactory()
-          .setCurrency(usd)
+          .setCurrency(usd)
-          .setNumber(200)
+          .setNumber(200)
-          .create();
+          .create();
-        Money moneyof = Money.of(12, usd);
+        Money moneyof = Money.of(12, usd);
-        FastMoney fastmoneyof = FastMoney.of(2, usd);
+        FastMoney fastmoneyof = FastMoney.of(2, usd);
-
+
-        assertEquals("USD", usd.toString());
+        assertEquals("USD", usd.toString());
-        assertEquals("USD 200", fstAmtUSD.toString());
+        assertEquals("USD 200", fstAmtUSD.toString());
-        assertEquals("USD 12", moneyof.toString());
+        assertEquals("USD 12", moneyof.toString());
-        assertEquals("USD 2.00000", fastmoneyof.toString());
+        assertEquals("USD 2.00000", fastmoneyof.toString());
-    }
+    }
-
+
-    @Test
+    @Test
-    public void givenCurrencies_whenCompared_thanNotequal() {
+    public void givenCurrencies_whenCompared_thanNotequal() {
-        MonetaryAmount oneDolar = Monetary
+        MonetaryAmount oneDolar = Monetary
-          .getDefaultAmountFactory()
+          .getDefaultAmountFactory()
-          .setCurrency("USD")
+          .setCurrency("USD")
-          .setNumber(1)
+          .setNumber(1)
-          .create();
+          .create();
-        Money oneEuro = Money.of(1, "EUR");
+        Money oneEuro = Money.of(1, "EUR");
-
+
-        assertFalse(oneEuro.equals(FastMoney.of(1, "EUR")));
+        assertFalse(oneEuro.equals(FastMoney.of(1, "EUR")));
-        assertTrue(oneDolar.equals(Money.of(1, "USD")));
+        assertTrue(oneDolar.equals(Money.of(1, "USD")));
-    }
+    }
-
+
-    @Test(expected = ArithmeticException.class)
+    @Test(expected = ArithmeticException.class)
-    public void givenAmount_whenDivided_thanThrowsException() {
+    public void givenAmount_whenDivided_thanThrowsException() {
-        MonetaryAmount oneDolar = Monetary
+        MonetaryAmount oneDolar = Monetary
-          .getDefaultAmountFactory()
+          .getDefaultAmountFactory()
-          .setCurrency("USD")
+          .setCurrency("USD")
-          .setNumber(1)
+          .setNumber(1)
-          .create();
+          .create();
-        oneDolar.divide(3);
+        oneDolar.divide(3);
-        fail(); // if no exception
+        fail(); // if no exception
-    }
+    }
-
+
-    @Test
+    @Test
-    public void givenAmounts_whenSummed_thanCorrect() {
+    public void givenAmounts_whenSummed_thanCorrect() {
-        List<MonetaryAmount> monetaryAmounts = Arrays.asList(Money.of(100, "CHF"), Money.of(10.20, "CHF"), Money.of(1.15, "CHF"));
+        List<MonetaryAmount> monetaryAmounts = Arrays.asList(Money.of(100, "CHF"), Money.of(10.20, "CHF"), Money.of(1.15, "CHF"));
-
+
-        Money sumAmtCHF = (Money) monetaryAmounts
+        Money sumAmtCHF = (Money) monetaryAmounts
-          .stream()
+          .stream()
-          .reduce(Money.of(0, "CHF"), MonetaryAmount::add);
+          .reduce(Money.of(0, "CHF"), MonetaryAmount::add);
-
+
-        assertEquals("CHF 111.35", sumAmtCHF.toString());
+        assertEquals("CHF 111.35", sumAmtCHF.toString());
-    }
+    }
-
+
-    @Test
+    @Test
-    public void givenArithmetic_whenStringified_thanEqualsAmount() {
+    public void givenArithmetic_whenStringified_thanEqualsAmount() {
-        CurrencyUnit usd = Monetary.getCurrency("USD");
+        CurrencyUnit usd = Monetary.getCurrency("USD");
-
+
-        Money moneyof = Money.of(12, usd);
+        Money moneyof = Money.of(12, usd);
-        MonetaryAmount fstAmtUSD = Monetary
+        MonetaryAmount fstAmtUSD = Monetary
-          .getDefaultAmountFactory()
+          .getDefaultAmountFactory()
-          .setCurrency(usd)
+          .setCurrency(usd)
-          .setNumber(200.50)
+          .setNumber(200.50)
-          .create();
+          .create();
-        MonetaryAmount oneDolar = Monetary
+        MonetaryAmount oneDolar = Monetary
-          .getDefaultAmountFactory()
+          .getDefaultAmountFactory()
-          .setCurrency("USD")
+          .setCurrency("USD")
-          .setNumber(1)
+          .setNumber(1)
-          .create();
+          .create();
-        Money subtractedAmount = Money
+        Money subtractedAmount = Money
-          .of(1, "USD")
+          .of(1, "USD")
-          .subtract(fstAmtUSD);
+          .subtract(fstAmtUSD);
-        MonetaryAmount multiplyAmount = oneDolar.multiply(0.25);
+        MonetaryAmount multiplyAmount = oneDolar.multiply(0.25);
-        MonetaryAmount divideAmount = oneDolar.divide(0.25);
+        MonetaryAmount divideAmount = oneDolar.divide(0.25);
-
+
-        assertEquals("USD", usd.toString());
+        assertEquals("USD", usd.toString());
-        assertEquals("USD 1", oneDolar.toString());
+        assertEquals("USD 1", oneDolar.toString());
-        assertEquals("USD 200.5", fstAmtUSD.toString());
+        assertEquals("USD 200.5", fstAmtUSD.toString());
-        assertEquals("USD 12", moneyof.toString());
+        assertEquals("USD 12", moneyof.toString());
-        assertEquals("USD -199.5", subtractedAmount.toString());
+        assertEquals("USD -199.5", subtractedAmount.toString());
-        assertEquals("USD 0.25", multiplyAmount.toString());
+        assertEquals("USD 0.25", multiplyAmount.toString());
-        assertEquals("USD 4", divideAmount.toString());
+        assertEquals("USD 4", divideAmount.toString());
-    }
+    }
-
+
-    @Test
+    @Test
-    public void givenAmount_whenRounded_thanEquals() {
+    public void givenAmount_whenRounded_thanEquals() {
-        MonetaryAmount fstAmtEUR = Monetary
+        MonetaryAmount fstAmtEUR = Monetary
-          .getDefaultAmountFactory()
+          .getDefaultAmountFactory()
-          .setCurrency("EUR")
+          .setCurrency("EUR")
-          .setNumber(1.30473908)
+          .setNumber(1.30473908)
-          .create();
+          .create();
-        MonetaryAmount roundEUR = fstAmtEUR.with(Monetary.getDefaultRounding());
+        MonetaryAmount roundEUR = fstAmtEUR.with(Monetary.getDefaultRounding());
-        assertEquals("EUR 1.30473908", fstAmtEUR.toString());
+        assertEquals("EUR 1.30473908", fstAmtEUR.toString());
-        assertEquals("EUR 1.3", roundEUR.toString());
+        assertEquals("EUR 1.3", roundEUR.toString());
-    }
+    }
-
+
-    @Test
+    @Test
-    @Ignore("Currency providers are not always available")
+    @Ignore("Currency providers are not always available")
-    public void givenAmount_whenConversion_thenNotNull() {
+    public void givenAmount_whenConversion_thenNotNull() {
-        MonetaryAmount oneDollar = Monetary
+        MonetaryAmount oneDollar = Monetary
-          .getDefaultAmountFactory()
+          .getDefaultAmountFactory()
-          .setCurrency("USD")
+          .setCurrency("USD")
-          .setNumber(1)
+          .setNumber(1)
-          .create();
+          .create();
-
+
-        CurrencyConversion conversionEUR = MonetaryConversions.getConversion("EUR");
+        CurrencyConversion conversionEUR = MonetaryConversions.getConversion("EUR");
-
+
-        MonetaryAmount convertedAmountUSDtoEUR = oneDollar.with(conversionEUR);
+        MonetaryAmount convertedAmountUSDtoEUR = oneDollar.with(conversionEUR);
-
+
-        assertEquals("USD 1", oneDollar.toString());
+        assertEquals("USD 1", oneDollar.toString());
-        assertNotNull(convertedAmountUSDtoEUR);
+        assertNotNull(convertedAmountUSDtoEUR);
-    }
+    }
-
+
-    @Test
+    @Test
-    public void givenLocale_whenFormatted_thanEquals() {
+    public void givenLocale_whenFormatted_thanEquals() {
-        MonetaryAmount oneDollar = Monetary
+        MonetaryAmount oneDollar = Monetary
-          .getDefaultAmountFactory()
+          .getDefaultAmountFactory()
-          .setCurrency("USD")
+          .setCurrency("USD")
-          .setNumber(1)
+          .setNumber(1)
-          .create();
+          .create();
-        MonetaryAmountFormat formatUSD = MonetaryFormats.getAmountFormat(Locale.US);
+        MonetaryAmountFormat formatUSD = MonetaryFormats.getAmountFormat(Locale.US);
-        String usFormatted = formatUSD.format(oneDollar);
+        String usFormatted = formatUSD.format(oneDollar);
-
+
-        assertEquals("USD 1", oneDollar.toString());
+        assertEquals("USD 1", oneDollar.toString());
-        assertNotNull(formatUSD);
+        assertNotNull(formatUSD);
-        assertEquals("USD1.00", usFormatted);
+        assertEquals("USD1.00", usFormatted);
-    }
+    }
-
+
-    @Test
+    @Test
-    public void givenAmount_whenCustomFormat_thanEquals() {
+    public void givenAmount_whenCustomFormat_thanEquals() {
-        MonetaryAmount oneDollar = Monetary
+        MonetaryAmount oneDollar = Monetary
-          .getDefaultAmountFactory()
+          .getDefaultAmountFactory()
-          .setCurrency("USD")
+          .setCurrency("USD")
-          .setNumber(1)
+          .setNumber(1)
-          .create();
+          .create();
-
+
-        MonetaryAmountFormat customFormat = MonetaryFormats.getAmountFormat(AmountFormatQueryBuilder
+        MonetaryAmountFormat customFormat = MonetaryFormats.getAmountFormat(AmountFormatQueryBuilder
-          .of(Locale.US)
+          .of(Locale.US)
-          .set(CurrencyStyle.NAME)
+          .set(CurrencyStyle.NAME)
-          .set("pattern", "00000.00 ¤")
+          .set("pattern", "00000.00 <EFBFBD>")
-          .build());
+          .build());
-        String customFormatted = customFormat.format(oneDollar);
+        String customFormatted = customFormat.format(oneDollar);
-
+
-        assertNotNull(customFormat);
+        assertNotNull(customFormat);
-        assertEquals("USD 1", oneDollar.toString());
+        assertEquals("USD 1", oneDollar.toString());
-        assertEquals("00001.00 US Dollar", customFormatted);
+        assertEquals("00001.00 US Dollar", customFormatted);
-    }
+    }
-}
+}

core-java/src/test/java/com/baeldung/stream/StreamToImmutableTest.java

@@ -0,0 +1,65 @@
+package com.baeldung.stream;
+
+import static java.util.stream.Collectors.collectingAndThen;
+import static java.util.stream.Collectors.toList;
+import static java.util.stream.Collectors.toSet;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.stream.IntStream;
+
+import org.junit.Test;
+
+import com.baeldung.stream.mycollectors.MyImmutableListCollector;
+import com.google.common.collect.ImmutableList;
+
+public class StreamToImmutableTest {
+
+    @Test
+    public void whenUsingCollectingToImmutableSet_thenSuccess() {
+        List<String> givenList = Arrays.asList("a", "b", "c");
+        List<String> result = givenList.stream()
+            .collect(collectingAndThen(toSet(), ImmutableList::copyOf));
+
+        System.out.println(result.getClass());
+    }
+
+    @Test
+    public void whenUsingCollectingToUnmodifiableList_thenSuccess() {
+        List<String> givenList = new ArrayList<>(Arrays.asList("a", "b", "c"));
+        List<String> result = givenList.stream()
+            .collect(collectingAndThen(toList(), Collections::unmodifiableList));
+
+        System.out.println(result.getClass());
+    }
+
+    @Test
+    public void whenCollectToImmutableList_thenSuccess() {
+        List<Integer> list = IntStream.range(0, 9)
+            .boxed()
+            .collect(ImmutableList.toImmutableList());
+
+        System.out.println(list.getClass());
+    }
+
+    @Test
+    public void whenCollectToMyImmutableListCollector_thenSuccess() {
+        List<String> givenList = Arrays.asList("a", "b", "c", "d");
+        List<String> result = givenList.stream()
+            .collect(MyImmutableListCollector.toImmutableList());
+
+        System.out.println(result.getClass());
+    }
+
+    @Test
+    public void whenPassingSupplier_thenSuccess() {
+        List<String> givenList = Arrays.asList("a", "b", "c", "d");
+        List<String> result = givenList.stream()
+            .collect(MyImmutableListCollector.toImmutableList(LinkedList::new));
+
+        System.out.println(result.getClass());
+    }
+}

core-java/src/test/java/com/baeldung/stream/mycollectors/MyImmutableListCollector.java

@@ -0,0 +1,22 @@
+package com.baeldung.stream.mycollectors;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.Supplier;
+import java.util.stream.Collector;
+
+public class MyImmutableListCollector {
+
+    public static <T, A extends List<T>> Collector<T, A, List<T>> toImmutableList(Supplier<A> supplier) {
+        return Collector.of(supplier, List::add, (left, right) -> {
+            left.addAll(right);
+            return left;
+        }, Collections::unmodifiableList);
+    }
+
+    public static <T> Collector<T, List<T>, List<T>> toImmutableList() {
+        return toImmutableList(ArrayList::new);
+    }
+
+}

core-java/src/test/java/com/baeldung/threadpool/CoreThreadPoolIntegrationTest.java

@@ -13,7 +13,6 @@ public class CoreThreadPoolIntegrationTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(CoreThreadPoolIntegrationTest.class);
 
-
     @Test(timeout = 1000)
     public void whenCallingExecuteWithRunnable_thenRunnableIsExecuted() throws InterruptedException {
 

feign/README.md

@@ -4,5 +4,5 @@ This is the implementation of a [spring-hypermedia-api][1] client using Feign.
 
 [1]: https://github.com/eugenp/spring-hypermedia-api
 
-###Relevant Articles:
+### Relevant Articles:
 - [Intro to Feign](http://www.baeldung.com/intro-to-feign)

grpc/pom.xml

@@ -0,0 +1,74 @@
+<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>grpc</groupId>
+    <artifactId>grpc-demo</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>grpc-demo</name>
+    <url>http://maven.apache.org</url>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <io.grpc.version>1.5.0</io.grpc.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-netty</artifactId>
+            <version>${io.grpc.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-protobuf</artifactId>
+            <version>${io.grpc.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-stub</artifactId>
+            <version>${io.grpc.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <extensions>
+            <extension>
+                <groupId>kr.motd.maven</groupId>
+                <artifactId>os-maven-plugin</artifactId>
+                <version>1.5.0.Final</version>
+            </extension>
+        </extensions>
+        <plugins>
+            <plugin>
+                <groupId>org.xolstice.maven.plugins</groupId>
+                <artifactId>protobuf-maven-plugin</artifactId>
+                <version>0.5.0</version>
+                <configuration>
+                    <protocArtifact>
+                        com.google.protobuf:protoc:3.3.0:exe:${os.detected.classifier}
+                    </protocArtifact>
+                    <pluginId>grpc-java</pluginId>
+                    <pluginArtifact>
+                        io.grpc:protoc-gen-grpc-java:1.4.0:exe:${os.detected.classifier}
+                    </pluginArtifact>
+                </configuration>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>compile</goal>
+                            <goal>compile-custom</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

grpc/src/main/java/org/baeldung/grpc/client/GrpcClient.java

@@ -0,0 +1,28 @@
+package org.baeldung.grpc.client;
+
+import org.baeldung.grpc.HelloRequest;
+import org.baeldung.grpc.HelloResponse;
+import org.baeldung.grpc.HelloServiceGrpc;
+
+import io.grpc.ManagedChannel;
+import io.grpc.ManagedChannelBuilder;
+
+public class GrpcClient {
+    public static void main(String[] args) throws InterruptedException {
+        ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 8080)
+            .usePlaintext(true)
+            .build();
+
+        HelloServiceGrpc.HelloServiceBlockingStub stub 
+          = HelloServiceGrpc.newBlockingStub(channel);
+
+        HelloResponse helloResponse = stub.hello(HelloRequest.newBuilder()
+            .setFirstName("Baeldung")
+            .setLastName("gRPC")
+            .build());
+
+        System.out.println("Response received from server:\n" + helloResponse);
+
+        channel.shutdown();
+    }
+}

grpc/src/main/java/org/baeldung/grpc/server/GrpcServer.java

@@ -0,0 +1,18 @@
+package org.baeldung.grpc.server;
+
+import java.io.IOException;
+
+import io.grpc.Server;
+import io.grpc.ServerBuilder;
+
+public class GrpcServer {
+    public static void main(String[] args) throws IOException, InterruptedException {
+        Server server = ServerBuilder.forPort(8080)
+          .addService(new HelloServiceImpl()).build();
+
+        System.out.println("Starting server...");
+        server.start();
+        System.out.println("Server started!");
+        server.awaitTermination();
+    }
+}

grpc/src/main/java/org/baeldung/grpc/server/HelloServiceImpl.java

@@ -0,0 +1,29 @@
+package org.baeldung.grpc.server;
+
+import org.baeldung.grpc.HelloRequest;
+import org.baeldung.grpc.HelloResponse;
+import org.baeldung.grpc.HelloServiceGrpc.HelloServiceImplBase;
+
+import io.grpc.stub.StreamObserver;
+
+public class HelloServiceImpl extends HelloServiceImplBase {
+
+    @Override
+    public void hello(
+      HelloRequest request, StreamObserver<HelloResponse> responseObserver) {
+        System.out.println("Request received from client:\n" + request);
+
+        String greeting = new StringBuilder().append("Hello, ")
+            .append(request.getFirstName())
+            .append(" ")
+            .append(request.getLastName())
+            .toString();
+
+        HelloResponse response = HelloResponse.newBuilder()
+            .setGreeting(greeting)
+            .build();
+
+        responseObserver.onNext(response);
+        responseObserver.onCompleted();
+    }
+}

grpc/src/main/proto/HelloService.proto

@@ -0,0 +1,16 @@
+syntax = "proto3";
+option java_multiple_files = true;
+package org.baeldung.grpc;
+
+message HelloRequest {
+    string firstName = 1;
+    string lastName = 2;
+}
+
+message HelloResponse {
+    string greeting = 1;
+}
+
+service HelloService {
+    rpc hello(HelloRequest) returns (HelloResponse);
+}

jee7/.gitignore

@@ -0,0 +1,5 @@
+
+/classes/
+/.idea/
+/target/
+/jee7.iml

jee7/pom.xml

@@ -6,8 +6,10 @@
 	<groupId>com.baeldung</groupId>
 	<artifactId>jee7</artifactId>
 	<version>1.0-SNAPSHOT</version>
+	<packaging>war</packaging>
 	<description>JavaEE 7 Arquillian Archetype Sample</description>
 
+
 	<parent>
 		<groupId>com.baeldung</groupId>
 		<artifactId>parent-modules</artifactId>
@@ -174,6 +176,7 @@
 				<artifactId>maven-war-plugin</artifactId>
 				<version>${maven-war-plugin.version}</version>
 				<configuration>
+					<warSourceDirectory>webapp</warSourceDirectory>
 					<failOnMissingWebXml>false</failOnMissingWebXml>
 				</configuration>
 			</plugin>

jee7/src/main/webapp/WEB-INF/spring/security.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<b:beans xmlns="http://www.springframework.org/schema/security"
+         xmlns:b="http://www.springframework.org/schema/beans"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
+		 http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security.xsd">
+
+    <authentication-manager>
+        <authentication-provider>
+            <user-service>
+                <user name="user" password="user123" authorities="ROLE_USER" />
+            </user-service>
+        </authentication-provider>
+    </authentication-manager>
+
+    <http auto-config='true' use-expressions="true">
+        <form-login default-target-url="/secure.jsp" />
+        <intercept-url pattern="/" access="isAnonymous()" />
+        <intercept-url pattern="/index.jsp" access="isAnonymous()" />
+        <intercept-url pattern="/secure.jsp" access="hasRole('ROLE_USER')" />
+    </http>
+
+</b:beans>

jee7/src/main/webapp/WEB-INF/web.xml

@@ -32,6 +32,33 @@
   <!-- If you go to http://host/project/ (with no file name), it will
        try index.jsf first, welcome.jsf next, and so forth.
    -->
+
+
+  <!-- UNCOMMENT THE FOLLOWING SECTION FOR SPRING SECURITY XML CONFIGURATION-->
+
+  <!--<context-param>-->
+    <!--<param-name>contextConfigLocation</param-name>-->
+    <!--<param-value>-->
+      <!--/WEB-INF/spring/*.xml-->
+    <!--</param-value>-->
+  <!--</context-param>-->
+
+  <!--<filter>-->
+    <!--<filter-name>springSecurityFilterChain</filter-name>-->
+    <!--<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>-->
+  <!--</filter>-->
+
+  <!--<filter-mapping>-->
+    <!--<filter-name>springSecurityFilterChain</filter-name>-->
+    <!--<url-pattern>/*</url-pattern>-->
+  <!--</filter-mapping>-->
+
+  <!--<listener>-->
+    <!--<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>-->
+  <!--</listener>-->
+
+  <!-- END SPRING SECURITY XML CONFIGURATION-->
+
   <welcome-file-list>
     <welcome-file>index.jsf</welcome-file>
     <welcome-file>welcome.jsf</welcome-file>

jee7/src/main/webapp/index.jsp

@@ -0,0 +1,11 @@
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<html>
+  <head>
+    <title>Index Page</title>
+  </head>
+  <body>
+  Non-secured Index Page
+  <br>
+  <a href="/login">Login</a>
+  </body>
+</html>

jee7/src/main/webapp/secure.jsp

@@ -0,0 +1,24 @@
+<%@ page language="java" contentType="text/html; charset=UTF-8"
+         pageEncoding="UTF-8"%>
+<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
+<%@ taglib uri="http://www.springframework.org/security/tags" prefix="sec" %>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+    <title>Home Page</title>
+</head>
+<body>
+<h3>Home Page</h3>
+
+<p>
+    Hello <b><c:out value="${pageContext.request.remoteUser}"/></b><br>
+    Roles: <b><sec:authentication property="principal.authorities" /></b>
+</p>
+
+<form action="logout" method="post">
+    <input type="submit" value="Logout" />
+    <input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}"/>
+</form>
+</body>
+</html>

jooq/README.md

@@ -1,3 +0,0 @@
-### Relevant articles
-
-- [Introduction to jOOL](http://www.baeldung.com/jool)

jooq/pom.xml

@@ -1,25 +0,0 @@
-<?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">
-    <parent>
-        <artifactId>parent-modules</artifactId>
-        <groupId>com.baeldung</groupId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-    <modelVersion>4.0.0</modelVersion>
-
-    <artifactId>jooq</artifactId>
-
-    <dependencies>
-        <dependency>
-            <groupId>org.jooq</groupId>
-            <artifactId>jool</artifactId>
-            <version>${jool.version}</version>
-        </dependency>
-    </dependencies>
-
-    <properties>
-        <jool.version>0.9.12</jool.version>
-    </properties>
-
-</project>

kotlin/src/main/kotlin/com/baeldung/kotlin/Sealed.kt

@@ -0,0 +1,19 @@
+package com.baeldung.kotlin
+
+sealed class Result<out S, out F> {
+    abstract fun <R> map(func: (S) -> R) : Result<R, F>
+    abstract fun <R> mapFailure(func: (F) -> R) : Result<S, R>
+    abstract fun get() : S?
+}
+
+data class Success<out S, out F>(val success: S) : Result<S, F>() {
+    override fun <R> map(func: (S) -> R) : Result<R, F> = Success(func(success))
+    override fun <R> mapFailure(func: (F) -> R): Result<S, R> = Success(success)
+    override fun get(): S? = success
+}
+
+data class Failure<out S, out F>(val failure: F) : Result<S, F>() {
+    override fun <R> map(func: (S) -> R) : Result<R, F> = Failure(failure)
+    override fun <R> mapFailure(func: (F) -> R): Result<S, R> = Failure(func(failure))
+    override fun get(): S? = null
+}

kotlin/src/main/kotlin/com/baeldung/kotlin/delegates/Database.kt

@@ -0,0 +1,35 @@
+package com.baeldung.kotlin.delegates
+
+val data = arrayOf<MutableMap<String, Any?>>(
+        mutableMapOf(
+                "id" to 1,
+                "name" to "George",
+                "age" to 4
+        ),
+        mutableMapOf(
+                "id" to 2,
+                "name" to "Charlotte",
+                "age" to 2
+        )
+)
+
+class NoRecordFoundException(id: Int) : Exception("No record found for id $id") {
+    init {
+        println("No record found for ID $id")
+    }
+}
+
+fun queryForValue(field: String, id: Int): Any {
+    println("Loading record $id from the fake database")
+    val value = data.firstOrNull { it["id"] == id }
+            ?.get(field) ?: throw NoRecordFoundException(id)
+    println("Loaded value $value for field $field of record $id")
+    return value
+}
+
+fun update(field: String, id: Int, value: Any?) {
+    println("Updating field $field of record $id to value $value in the fake database")
+    data.firstOrNull { it["id"] == id }
+            ?.put(field, value)
+            ?: throw NoRecordFoundException(id)
+}

kotlin/src/main/kotlin/com/baeldung/kotlin/delegates/DatabaseDelegate.kt

@@ -0,0 +1,13 @@
+package com.baeldung.kotlin.delegates
+
+import kotlin.properties.ReadWriteProperty
+import kotlin.reflect.KProperty
+
+class DatabaseDelegate<in R, T>(private val field: String, private val id: Int) : ReadWriteProperty<R, T> {
+    override fun getValue(thisRef: R, property: KProperty<*>): T =
+            queryForValue(field, id) as T
+
+    override fun setValue(thisRef: R, property: KProperty<*>, value: T) {
+        update(field, id, value)
+    }
+}

kotlin/src/main/kotlin/com/baeldung/kotlin/delegates/User.kt

@@ -0,0 +1,6 @@
+package com.baeldung.kotlin.delegates
+
+class User(val id: Int) {
+    var name: String by DatabaseDelegate("name", id)
+    var age: Int by DatabaseDelegate("age", id)
+}

kotlin/src/test/kotlin/com/baeldung/kotlin/SealedTest.kt

@@ -0,0 +1,84 @@
+package com.baeldung.kotlin
+
+import org.junit.Assert
+import org.junit.Test
+
+class SealedTest {
+    fun divide(a: Int, b: Int) : Result<Float, String> = when (b) {
+        0 -> Failure("Division by zero")
+        else -> Success(a.toFloat() / b)
+    }
+
+    @Test
+    fun testSuccess() {
+        val result = divide(10, 5)
+        Assert.assertEquals(Success<Float, String>(2.0f), result)
+    }
+
+    @Test
+    fun testError() {
+        val result = divide(10, 0)
+        Assert.assertEquals(Failure<Float, String>("Division by zero"), result)
+    }
+
+    @Test
+    fun testMatchOnSuccess() {
+        val result = divide(10, 5)
+        when (result) {
+            is Success -> {
+                // Expected
+            }
+            is Failure -> Assert.fail("Expected Success")
+        }
+    }
+
+    @Test
+    fun testMatchOnError() {
+        val result = divide(10, 0)
+        when (result) {
+            is Failure -> {
+                // Expected
+            }
+        }
+    }
+
+    @Test
+    fun testGetSuccess() {
+        val result = divide(10, 5)
+        Assert.assertEquals(2.0f, result.get())
+    }
+
+    @Test
+    fun testGetError() {
+        val result = divide(10, 0)
+        Assert.assertNull(result.get())
+    }
+
+    @Test
+    fun testMapOnSuccess() {
+        val result = divide(10, 5)
+                .map { "Result: $it" }
+        Assert.assertEquals(Success<String, String>("Result: 2.0"), result)
+    }
+
+    @Test
+    fun testMapOnError() {
+        val result = divide(10, 0)
+                .map { "Result: $it" }
+        Assert.assertEquals(Failure<Float, String>("Division by zero"), result)
+    }
+
+    @Test
+    fun testMapFailureOnSuccess() {
+        val result = divide(10, 5)
+                .mapFailure { "Failure: $it" }
+        Assert.assertEquals(Success<Float, String>(2.0f), result)
+    }
+
+    @Test
+    fun testMapFailureOnError() {
+        val result = divide(10, 0)
+                .mapFailure { "Failure: $it" }
+        Assert.assertEquals(Failure<Float, String>("Failure: Division by zero"), result)
+    }
+}

kotlin/src/test/kotlin/com/baeldung/kotlin/delegates/DatabaseDelegatesTest.kt

@@ -0,0 +1,26 @@
+package com.baeldung.kotlin.delegates
+
+import org.junit.Test
+import kotlin.test.assertEquals
+
+class DatabaseDelegatesTest {
+    @Test
+    fun testGetKnownFields() {
+        val user = User(1)
+        assertEquals("George", user.name)
+        assertEquals(4, user.age)
+    }
+
+    @Test
+    fun testSetKnownFields() {
+        val user = User(2)
+        user.age = 3
+        assertEquals(3, user.age)
+    }
+
+    @Test(expected = NoRecordFoundException::class)
+    fun testGetKnownField() {
+        val user = User(3)
+        user.name
+    }
+}

libraries-data/pom.xml

@@ -0,0 +1,22 @@
+<?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>
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    <artifactId>libraries-data</artifactId>
+    <name>libraries-data</name>
+    <packaging>jar</packaging>
+    <dependencies>
+        <dependency>
+            <groupId>com.esotericsoftware</groupId>
+            <artifactId>kryo</artifactId>
+            <version>${kryo.version}</version>
+        </dependency>
+    </dependencies>
+    <properties>
+        <kryo.version>4.0.1</kryo.version>
+    </properties>
+</project>

libraries-data/src/main/java/com/baeldung/kryo/ComplexClass.java

@@ -0,0 +1,16 @@
+package com.baeldung.kryo;
+
+import java.io.Serializable;
+
+public class ComplexClass implements Serializable{
+    private static final long serialVersionUID = 123456L;
+    private String name = "Bael";
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

libraries-data/src/main/java/com/baeldung/kryo/Person.java

@@ -0,0 +1,54 @@
+package com.baeldung.kryo;
+
+import com.esotericsoftware.kryo.DefaultSerializer;
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.KryoSerializable;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+import java.util.Date;
+
+@DefaultSerializer(PersonSerializer.class)
+public class Person implements KryoSerializable {
+    private String name = "John Doe";
+    private int age = 18;
+    private Date birthDate = new Date(933191282821L);
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public Date getBirthDate() {
+        return birthDate;
+    }
+
+    public void setBirthDate(Date birthDate) {
+        this.birthDate = birthDate;
+    }
+
+    @Override
+    public void write(Kryo kryo, Output output) {
+        output.writeString(name);
+        output.writeLong(birthDate.getTime());
+        output.writeInt(age);
+    }
+
+    @Override
+    public void read(Kryo kryo, Input input) {
+        name = input.readString();
+        birthDate = new Date(input.readLong());
+        age = input.readInt();
+    }
+
+}

libraries-data/src/main/java/com/baeldung/kryo/PersonSerializer.java

@@ -0,0 +1,33 @@
+package com.baeldung.kryo;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.Serializer;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+import java.util.Date;
+
+public class PersonSerializer extends Serializer<Person> {
+
+    @Override
+    public void write(Kryo kryo, Output output, Person object) {
+        output.writeString(object.getName());
+        output.writeLong(object.getBirthDate()
+            .getTime());
+    }
+
+    @Override
+    public Person read(Kryo kryo, Input input, Class<Person> type) {
+        Person person = new Person();
+        person.setName(input.readString());
+        long birthDate = input.readLong();
+        person.setBirthDate(new Date(birthDate));
+        person.setAge(calculateAge(birthDate));
+        return person;
+    }
+
+    private int calculateAge(long birthDate) {
+        // Some custom logic
+        return 18;
+    }
+
+}

libraries-data/src/test/java/com/baeldung/kryo/KryoUnitTest.java

@@ -0,0 +1,125 @@
+package com.baeldung.kryo;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.util.Date;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+import com.esotericsoftware.kryo.serializers.JavaSerializer;
+
+public class KryoUnitTest {
+
+    private Kryo kryo;
+    private Output output;
+    private Input input;
+
+    @Before
+    public void init() {
+        kryo = new Kryo();
+        try {
+            output = new Output(new FileOutputStream("file.dat"));
+            input = new Input(new FileInputStream("file.dat"));
+        } catch (FileNotFoundException ex) {
+            Logger.getLogger(KryoUnitTest.class.getName())
+                .log(Level.SEVERE, null, ex);
+        }
+    }
+
+    @Test
+    public void givenObject_whenSerializing_thenReadCorrectly() {
+        Object someObject = "Some string";
+
+        kryo.writeClassAndObject(output, someObject);
+        output.close();
+
+        Object theObject = kryo.readClassAndObject(input);
+        input.close();
+
+        assertEquals(theObject, "Some string");
+    }
+
+    @Test
+    public void givenObjects_whenSerializing_thenReadCorrectly() {
+        String someString = "Multiple Objects";
+        Date someDate = new Date(915170400000L);
+
+        kryo.writeObject(output, someString);
+        kryo.writeObject(output, someDate);
+        output.close();
+
+        String readString = kryo.readObject(input, String.class);
+        Date readDate = kryo.readObject(input, Date.class);
+        input.close();
+
+        assertEquals(readString, "Multiple Objects");
+        assertEquals(readDate.getTime(), 915170400000L);
+    }
+
+    @Test
+    public void givenPerson_whenSerializing_thenReadCorrectly() {
+        Person person = new Person();
+
+        kryo.writeObject(output, person);
+        output.close();
+
+        Person readPerson = kryo.readObject(input, Person.class);
+        input.close();
+
+        assertEquals(readPerson.getName(), "John Doe");
+    }
+
+    @Test
+    public void givenPerson_whenUsingCustomSerializer_thenReadCorrectly() {
+        Person person = new Person();
+        person.setAge(0);
+        kryo.register(Person.class, new PersonSerializer());
+
+        kryo.writeObject(output, person);
+        output.close();
+
+        Person readPerson = kryo.readObject(input, Person.class);
+        input.close();
+
+        assertEquals(readPerson.getName(), "John Doe");
+        assertEquals(readPerson.getAge(), 18);
+    }
+    
+    @Test
+    public void givenPerson_whenCustomSerialization_thenReadCorrectly() {
+        Person person = new Person();
+
+        kryo.writeObject(output, person);
+        output.close();
+
+        Person readPerson = kryo.readObject(input, Person.class);
+        input.close();
+
+        assertEquals(readPerson.getName(), "John Doe");
+        assertEquals(readPerson.getAge(), 18);
+    }
+
+    @Test
+    public void givenJavaSerializable_whenSerializing_thenReadCorrectly() {
+        ComplexClass complexClass = new ComplexClass();
+        kryo.register(ComplexClass.class, new JavaSerializer());
+
+        kryo.writeObject(output, complexClass);
+        output.close();
+
+        ComplexClass readComplexObject = kryo.readObject(input, ComplexClass.class);
+        input.close();
+
+        assertEquals(readComplexObject.getName(), "Bael");
+    }
+
+}

libraries/README.md

@@ -27,6 +27,8 @@
 - [Introduction to Awaitility](http://www.baeldung.com/awaitlity-testing)
 - [Guide to the HyperLogLog Algorithm](http://www.baeldung.com/java-hyperloglog)
 - [Introduction to Neuroph](http://www.baeldung.com/intro-to-neuroph)
+- [Guide to Apache Commons CircularFifoQueue](http://www.baeldung.com/commons-circular-fifo-queue)
+- [Quick Guide to RSS with Rome](http://www.baeldung.com/rome-rss)
 
 The libraries module contains examples related to small libraries that are relatively easy to use and does not require any separate module of its own.
 

libraries/pom.xml

@@ -20,7 +20,6 @@
 						<artifactId>maven-bundle-plugin</artifactId>
 						<version>3.3.0</version>
 						<type>maven-plugin</type>
-
 					</dependency>
 				</dependencies>
 				<extensions>true</extensions>
@@ -182,6 +181,16 @@
 			<artifactId>jetty-servlet</artifactId>
 			<version>${jetty.version}</version>
 		</dependency>
+		<dependency>
+			<groupId>rome</groupId>
+			<artifactId>rome</artifactId>
+			<version>${rome.version}</version>
+		</dependency>
+	    <dependency>
+	      <groupId>io.specto</groupId>
+	      <artifactId>hoverfly-java</artifactId>
+	      <version>0.8.0</version>
+	    </dependency>
 		<dependency>
 			<groupId>org.apache.httpcomponents</groupId>
 			<artifactId>httpclient</artifactId>
@@ -453,12 +462,11 @@
 			<artifactId>pcollections</artifactId>
 			<version>${pcollections.version}</version>
 		</dependency>
-		<dependency>
+    <dependency>
 			<groupId>org.eclipse.collections</groupId>
 			<artifactId>eclipse-collections</artifactId>
 			<version>${eclipse-collections.version}</version>
 		</dependency>
-
 	</dependencies>
 	<properties>
 		<multiverse.version>0.7.0</multiverse.version>
@@ -499,6 +507,7 @@
 		<hll.version>1.6.0</hll.version>
 		<bytebuddy.version>1.7.1</bytebuddy.version>
 		<pcollections.version>2.1.2</pcollections.version>
-		<eclipse-collections.version>8.2.0</eclipse-collections.version>
+		<rome.version>1.0</rome.version>
+    <eclipse-collections.version>8.2.0</eclipse-collections.version>
 	</properties>
-</project>
+</project>

libraries/src/main/java/com/baeldung/rome/RSSRomeExample.java

@@ -0,0 +1,76 @@
+package com.baeldung.rome;
+
+import com.sun.syndication.feed.synd.*;
+import com.sun.syndication.io.FeedException;
+import com.sun.syndication.io.SyndFeedInput;
+import com.sun.syndication.io.SyndFeedOutput;
+import com.sun.syndication.io.XmlReader;
+
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.Writer;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class RSSRomeExample {
+
+    public static void main(String[] args) throws IOException, FeedException {
+        SyndFeed feed = createFeed();
+        addEntryToFeed(feed);
+        publishFeed(feed);
+        readFeed();
+    }
+
+    private static SyndFeed createFeed() {
+        SyndFeed feed = new SyndFeedImpl();
+        feed.setFeedType("rss_1.0");
+        feed.setTitle("Test title");
+        feed.setLink("http://www.somelink.com");
+        feed.setDescription("Basic description");
+
+        return feed;
+    }
+
+    private static void addEntryToFeed(SyndFeed feed) {
+        SyndEntry entry = new SyndEntryImpl();
+        entry.setTitle("Entry title");
+        entry.setLink("http://www.somelink.com/entry1");
+
+        addDescriptionToEntry(entry);
+        addCategoryToEntry(entry);
+
+        feed.setEntries(Arrays.asList(entry));
+    }
+
+    private static void addDescriptionToEntry(SyndEntry entry) {
+        SyndContent description = new SyndContentImpl();
+        description.setType("text/html");
+        description.setValue("First entry");
+
+        entry.setDescription(description);
+    }
+
+    private static void addCategoryToEntry(SyndEntry entry) {
+        List<SyndCategory> categories = new ArrayList<>();
+        SyndCategory category = new SyndCategoryImpl();
+        category.setName("Sophisticated category");
+        categories.add(category);
+
+        entry.setCategories(categories);
+    }
+
+    private static void publishFeed(SyndFeed feed) throws IOException, FeedException {
+        Writer writer = new FileWriter("xyz.txt");
+        SyndFeedOutput syndFeedOutput = new SyndFeedOutput();
+        syndFeedOutput.output(feed, writer);
+        writer.close();
+    }
+
+    private static SyndFeed readFeed() throws IOException, FeedException {
+        URL feedSource = new URL("http://rssblog.whatisrss.com/feed/");
+        SyndFeedInput input = new SyndFeedInput();
+        return input.build(new XmlReader(feedSource));
+    }
+}

libraries/src/main/java/com/baeldung/streamutils/CopyStream.java

@@ -0,0 +1,22 @@
+package com.baeldung.streamutils;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.StringWriter;
+
+import org.apache.commons.io.IOUtils;
+import org.springframework.util.StreamUtils;
+
+public class CopyStream {
+	public static String getStringFromInputStream(InputStream input) throws IOException {
+		StringWriter writer = new StringWriter();
+		IOUtils.copy(input, writer, "UTF-8");
+		return writer.toString();
+	}
+
+	public InputStream getNonClosingInputStream() throws IOException {
+		InputStream in = new FileInputStream("src/test/resources/input.txt");
+		return StreamUtils.nonClosing(in);
+	}
+}

libraries/src/main/java/com/baeldung/streamutils/DrainStream.java

@@ -0,0 +1,11 @@
+package com.baeldung.streamutils;
+
+import java.io.InputStream;
+
+import org.springframework.util.StreamUtils;
+
+public class DrainStream {
+	public InputStream getInputStream() {
+		return StreamUtils.emptyInput();
+	}
+}