Merge branch 'master' into JAVA-5223

core-java-modules/core-java-11-2/pom.xml

@@ -50,6 +50,11 @@
             <version>${junit.jupiter.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -73,6 +78,7 @@
         <junit.jupiter.version>5.7.0</junit.jupiter.version>
         <assertj.version>3.17.2</assertj.version>
         <mockserver.version>5.11.1</mockserver.version>
+        <commons-lang3.version>3.12.0</commons-lang3.version>
     </properties>
 
 </project>

core-java-modules/core-java-11-2/src/test/java/com/baeldung/version/VersionUnitTest.java

@@ -0,0 +1,48 @@
+package com.baeldung.version;
+
+import org.apache.commons.lang3.SystemUtils;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+public class VersionUnitTest {
+
+    @Test
+    public void givenJava_whenUsingRuntime_thenGetVersion() {
+        String expectedVersion = "11";
+        Runtime.Version runtimeVersion = Runtime.version();
+        String version = String.valueOf(runtimeVersion.version().get(0));
+        Assertions.assertThat(version).isEqualTo(expectedVersion);
+    }
+
+    @Test
+    @Disabled("Only valid for Java 8 and lower")
+    public void givenJava_whenUsingCommonsLang_thenGetVersion() {
+        int expectedVersion = 8;
+        String[] versionElements = SystemUtils.JAVA_SPECIFICATION_VERSION.split("\\.");
+        int discard = Integer.parseInt(versionElements[0]);
+        int version;
+        if (discard == 1) {
+            version = Integer.parseInt(versionElements[1]);
+        } else {
+            version = discard;
+        }
+        Assertions.assertThat(version).isEqualTo(expectedVersion);
+    }
+
+    @Test
+    @Disabled("Only valid for Java 8 and lower")
+    public void givenJava_whenUsingSystemProp_thenGetVersion() {
+        int expectedVersion = 8;
+        String[] versionElements = System.getProperty("java.version").split("\\.");
+        int discard = Integer.parseInt(versionElements[0]);
+        int version;
+        if (discard == 1) {
+            version = Integer.parseInt(versionElements[1]);
+        } else {
+            version = discard;
+        }
+        Assertions.assertThat(version).isEqualTo(expectedVersion);
+    }
+}
+

core-java-modules/core-java-jpms/decoupling-pattern2/consumermodule2/pom.xml

@@ -45,4 +45,4 @@
         <providermodule.version>1.0</providermodule.version>
     </properties>
 
-</project>
+</project>

core-java-modules/core-java-lang-4/src/main/java/com/baeldung/hash/Player.java

@@ -0,0 +1,91 @@
+package com.baeldung.hash;
+
+import java.util.Objects;
+
+public class Player {
+    private String firstName;
+    private String lastName;
+    private String position;
+
+    public Player() {
+
+    }
+
+    public Player(String firstName, String lastName, String position) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.position = position;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public String getPosition() {
+        return position;
+    }
+
+    public void setPosition(String position) {
+        this.position = position;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(firstName, lastName, position);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (obj == null) {
+            return false;
+        }
+
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+
+        Player other = (Player) obj;
+
+        if (firstName == null) {
+            if (other.firstName != null) {
+                return false;
+            }
+        } else if (!firstName.equals(other.firstName)) {
+            return false;
+        }
+
+        if (lastName == null) {
+            if (other.lastName != null) {
+                return false;
+            }
+        } else if (!lastName.equals(other.lastName)) {
+            return false;
+        }
+
+        if (position == null) {
+            if (other.position != null) {
+                return false;
+            }
+        } else if (!position.equals(other.position)) {
+            return false;
+        }
+        return true;
+    }
+
+}

core-java-modules/core-java-lang-4/src/test/java/com/baeldung/hash/HashCodeUnitTest.java

@@ -0,0 +1,67 @@
+package com.baeldung.hash;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+
+import java.util.Objects;
+
+import org.junit.Test;
+
+public class HashCodeUnitTest {
+
+    @Test
+    public void whenCallingObjectsHashCodeOnIndenticalObjects_thenSameHashCodeReturned() {
+        String stringOne = "test";
+        String stringTwo = "test";
+        int hashCode1 = Objects.hashCode(stringOne);
+        int hashCode2 = Objects.hashCode(stringTwo);
+
+        assertEquals(hashCode1, hashCode2);
+    }
+
+    @Test
+    public void whenCallingObjectsHashCodeOnNullObject_thenZeroReturned() {
+        String nullString = null;
+        int hashCode = Objects.hashCode(nullString);
+        assertEquals(0, hashCode);
+    }
+
+    @Test
+    public void whenCallingObjectHashCodeOnIndenticalObjects_thenSameHashCodeReturned() {
+        Double valueOne = Double.valueOf(1.0012);
+        Double valueTwo = Double.valueOf(1.0012);
+
+        int hashCode1 = valueOne.hashCode();
+        int hashCode2 = valueTwo.hashCode();
+
+        assertEquals(hashCode1, hashCode2);
+    }
+
+    @Test(expected = NullPointerException.class)
+    public void whenCallingObjectHashCodeOnNullObject_theNullPointerExceptionThrown() {
+        Double value = null;
+        value.hashCode();
+    }
+
+    @Test
+    public void whenCallingObjectsHashOnStrings_thenSameHashCodeReturned() {
+        String strOne = "one";
+        String strTwo = "two";
+        String strOne2 = "one";
+        String strTwo2 = "two";
+
+        int hashCode1 = Objects.hash(strOne, strTwo);
+        int hashCode2 = Objects.hash(strOne2, strTwo2);
+
+        assertEquals(hashCode1, hashCode2);
+    }
+
+    @Test
+    public void whenCallingObjectsHashOnSingleString_thenDifferentHashcodeFromObjectsHashCodeCallReturned() {
+        String testString = "test string";
+        int hashCode1 = Objects.hash(testString);
+        int hashCode2 = Objects.hashCode(testString);
+
+        assertNotEquals(hashCode1, hashCode2);
+    }
+}

core-java-modules/core-java-lang-4/src/test/java/com/baeldung/hash/PlayerUnitTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.hash;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+
+import org.junit.Test;
+
+public class PlayerUnitTest {
+
+    @Test
+    public void whenCallingHashCodeOnIdenticalValue_thenSameHashCodeReturned() {
+        Player player = new Player("Eduardo", "Rodriguez", "Pitcher");
+        Player indenticalPlayer = new Player("Eduardo", "Rodriguez", "Pitcher");
+
+        int hashCode1 = player.hashCode();
+        int hashCode2 = player.hashCode();
+        int hashCode3 = indenticalPlayer.hashCode();
+
+        assertEquals(hashCode1, hashCode2);
+        assertEquals(hashCode1, hashCode3);
+    }
+
+    @Test
+    public void whenCallingHashCodeAndArraysHashCode_thenSameHashCodeReturned() {
+        Player player = new Player("Bobby", "Dalbec", "First Base");
+        int hashcode1 = player.hashCode();
+        String[] playerInfo = { "Bobby", "Dalbec", "First Base" };
+        int hashcode2 = Arrays.hashCode(playerInfo);
+
+        assertEquals(hashcode1, hashcode2);
+    }
+}

core-java-modules/core-java-lang-oop-patterns/src/main/java/com/baeldung/interfacevsabstractclass/Car.java

@@ -0,0 +1,42 @@
+package com.baeldung.interfacevsabstractclass;
+
+public class Car extends Vehicle {
+
+    public Car(String vechicleName) {
+        super(vechicleName);
+    }
+
+    public Car(String vechicleName, String vehicleModel) {
+        super(vechicleName, vehicleModel);
+    }
+
+    public Car(String vechicleName, String vehicleModel, Long makeYear) {
+        super(vechicleName, vehicleModel, makeYear);
+    }
+
+    @Override
+    protected void start() {
+        // code implementation details on starting a car.
+    }
+
+    @Override
+    protected void stop() {
+        // code implementation details on stopping a car.
+    }
+
+    @Override
+    protected void drive() {
+        // code implementation details on start driving a car.
+    }
+
+    @Override
+    protected void changeGear() {
+        // code implementation details on changing the car gear.
+    }
+
+    @Override
+    protected void reverse() {
+        // code implementation details on reverse driving a car.
+    }
+
+}

core-java-modules/core-java-lang-oop-patterns/src/main/java/com/baeldung/interfacevsabstractclass/ImageSender.java

@@ -0,0 +1,12 @@
+package com.baeldung.interfacevsabstractclass;
+
+import java.io.File;
+
+public class ImageSender implements Sender {
+
+    @Override
+    public void send(File fileToBeSent) {
+        // image sending implementation code.
+    }
+
+}

core-java-modules/core-java-lang-oop-patterns/src/main/java/com/baeldung/interfacevsabstractclass/Sender.java

@@ -0,0 +1,8 @@
+package com.baeldung.interfacevsabstractclass;
+
+import java.io.File;
+
+public interface Sender {
+
+    void send(File fileToBeSent);
+}

core-java-modules/core-java-lang-oop-patterns/src/main/java/com/baeldung/interfacevsabstractclass/Vehicle.java

@@ -0,0 +1,57 @@
+package com.baeldung.interfacevsabstractclass;
+
+public abstract class Vehicle {
+
+    private String vehicleName;
+    private String vehicleModel;
+    private Long makeYear;
+
+    public Vehicle(String vehicleName) {
+        this.vehicleName = vehicleName;
+    }
+
+    public Vehicle(String vehicleName, String vehicleModel) {
+        this(vehicleName);
+        this.vehicleModel = vehicleModel;
+    }
+
+    public Vehicle(String vechicleName, String vehicleModel, Long makeYear) {
+        this(vechicleName, vehicleModel);
+        this.makeYear = makeYear;
+    }
+
+    public String getVehicleName() {
+        return vehicleName;
+    }
+
+    public void setVehicleName(String vehicleName) {
+        this.vehicleName = vehicleName;
+    }
+
+    public String getVehicleModel() {
+        return vehicleModel;
+    }
+
+    public void setVehicleModel(String vehicleModel) {
+        this.vehicleModel = vehicleModel;
+    }
+
+    public Long getMakeYear() {
+        return makeYear;
+    }
+
+    public void setMakeYear(Long makeYear) {
+        this.makeYear = makeYear;
+    }
+
+    protected abstract void start();
+
+    protected abstract void stop();
+
+    protected abstract void drive();
+
+    protected abstract void changeGear();
+
+    protected abstract void reverse();
+
+}

core-java-modules/core-java-lang-oop-patterns/src/main/java/com/baeldung/interfacevsabstractclass/VideoSender.java

@@ -0,0 +1,12 @@
+package com.baeldung.interfacevsabstractclass;
+
+import java.io.File;
+
+public class VideoSender implements Sender {
+
+    @Override
+    public void send(File fileToBeSent) {
+        // video sending implementation code
+    }
+
+}

core-java-modules/core-java-lang-oop-patterns/src/test/java/com/baeldung/interfacevsabstractclass/SenderUnitTest.java

@@ -0,0 +1,23 @@
+package com.baeldung.interfacevsabstractclass;
+
+import static org.junit.jupiter.api.Assertions.*;
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.interfacevsabstractclass.ImageSender;
+import com.baeldung.interfacevsabstractclass.Sender;
+
+import java.io.File;
+
+class SenderUnitTest {
+
+    public final static String IMAGE_FILE_PATH = "/sample_image_file_path/photo.jpg";
+
+    @Test
+    void givenImageUploaded_whenButtonClicked_thenSendImage() {
+        File imageFile = new File(IMAGE_FILE_PATH);
+
+        Sender sender = new ImageSender();
+        sender.send(imageFile);
+    }
+
+}

core-java-modules/core-java-lang-oop-patterns/src/test/java/com/baeldung/interfacevsabstractclass/VehicleUnitTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.interfacevsabstractclass;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.interfacevsabstractclass.Car;
+import com.baeldung.interfacevsabstractclass.Vehicle;
+
+class VehicleUnitTest {
+
+    @Test
+    void givenVehicle_whenNeedToDrive_thenStart() {
+        Vehicle car = new Car("BMW");
+
+        car.start();
+        car.drive();
+        car.changeGear();
+        car.stop();
+    }
+
+}

core-java-modules/core-java-networking-2/src/test/java/com/baeldung/download/FileDownloadIntegrationTest.java

@@ -17,9 +17,9 @@ import static org.junit.Assert.assertTrue;
 
 public class FileDownloadIntegrationTest {
     
-    static String FILE_URL = "http://ovh.net/files/1Mio.dat";
+    static String FILE_URL = "https://s3.amazonaws.com/baeldung.com/Do+JSON+with+Jackson+by+Baeldung.pdf";
     static String FILE_NAME = "file.dat";
-    static String FILE_MD5_HASH = "6cb91af4ed4c60c11613b75cd1fc6116";
+    static String FILE_MD5_HASH = "c959feb066b37f5c4f0e0f45bbbb4f86";
     
     @Test
     public void givenJavaIO_whenDownloadingFile_thenDownloadShouldBeCorrect() throws NoSuchAlgorithmException, IOException {

core-java-modules/core-java-streams-3/pom.xml

@@ -27,6 +27,17 @@
             <version>${lombok.version}</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${jmh.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${jmh.version}</version>
+            <scope>test</scope>
+        </dependency>
         <!-- test scoped -->
         <dependency>
             <groupId>org.assertj</groupId>
@@ -44,11 +55,30 @@
                 <filtering>true</filtering>
             </resource>
         </resources>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                    <annotationProcessorPaths>
+                        <path>
+                            <groupId>org.openjdk.jmh</groupId>
+                            <artifactId>jmh-generator-annprocess</artifactId>
+                            <version>${jmh.version}</version>
+                        </path>
+                    </annotationProcessorPaths>
+                </configuration>
+            </plugin>
+        </plugins>
     </build>
 
     <properties>
+        <lombok.version>1.18.20</lombok.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
+        <jmh.version>1.29</jmh.version>
     </properties>
 
 </project>

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/BenchmarkRunner.java

@@ -0,0 +1,9 @@
+package com.baeldung.streams.parallel;
+
+public class BenchmarkRunner {
+
+    public static void main(String[] args) throws Exception {
+        org.openjdk.jmh.Main.main(args);
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/DifferentSourceSplitting.java

@@ -0,0 +1,54 @@
+package com.baeldung.streams.parallel;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.IntStream;
+
+public class DifferentSourceSplitting {
+
+    private static final List<Integer> arrayListOfNumbers = new ArrayList<>();
+    private static final List<Integer> linkedListOfNumbers = new LinkedList<>();
+
+    static {
+        IntStream.rangeClosed(1, 1_000_000).forEach(i -> {
+            arrayListOfNumbers.add(i);
+            linkedListOfNumbers.add(i);
+        });
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void differentSourceArrayListSequential() {
+        arrayListOfNumbers.stream().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void differentSourceArrayListParallel() {
+        arrayListOfNumbers.parallelStream().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void differentSourceLinkedListSequential() {
+        linkedListOfNumbers.stream().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void differentSourceLinkedListParallel() {
+        linkedListOfNumbers.parallelStream().reduce(0, Integer::sum);
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/MemoryLocalityCosts.java

@@ -0,0 +1,52 @@
+package com.baeldung.streams.parallel;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+
+import java.util.Arrays;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.IntStream;
+
+public class MemoryLocalityCosts {
+
+    private static final int[] intArray = new int[1_000_000];
+    private static final Integer[] integerArray = new Integer[1_000_000];
+
+    static {
+        IntStream.rangeClosed(1, 1_000_000).forEach(i -> {
+            intArray[i-1] = i;
+            integerArray[i-1] = i;
+        });
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void localityIntArraySequential() {
+        Arrays.stream(intArray).reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void localityIntArrayParallel() {
+        Arrays.stream(intArray).parallel().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void localityIntegerArraySequential() {
+        Arrays.stream(integerArray).reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void localityIntegerArrayParallel() {
+        Arrays.stream(integerArray).parallel().reduce(0, Integer::sum);
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/MergingCosts.java

@@ -0,0 +1,52 @@
+package com.baeldung.streams.parallel;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class MergingCosts {
+
+    private static final List<Integer> arrayListOfNumbers = new ArrayList<>();
+
+    static {
+        IntStream.rangeClosed(1, 1_000_000).forEach(i -> {
+            arrayListOfNumbers.add(i);
+        });
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void mergingCostsSumSequential() {
+        arrayListOfNumbers.stream().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void mergingCostsSumParallel() {
+        arrayListOfNumbers.stream().parallel().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void mergingCostsGroupingSequential() {
+        arrayListOfNumbers.stream().collect(Collectors.toSet());
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void mergingCostsGroupingParallel() {
+        arrayListOfNumbers.stream().parallel().collect(Collectors.toSet());
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/ParallelStream.java

@@ -0,0 +1,15 @@
+package com.baeldung.streams.parallel;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class ParallelStream {
+
+    public static void main(String[] args) {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        listOfNumbers.parallelStream().forEach(number ->
+          System.out.println(number + " " + Thread.currentThread().getName())
+        );
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/SequentialStream.java

@@ -0,0 +1,15 @@
+package com.baeldung.streams.parallel;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class SequentialStream {
+
+    public static void main(String[] args) {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        listOfNumbers.stream().forEach(number ->
+          System.out.println(number + " " + Thread.currentThread().getName())
+        );
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/SplittingCosts.java

@@ -0,0 +1,27 @@
+package com.baeldung.streams.parallel;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+
+import java.util.concurrent.TimeUnit;
+import java.util.stream.IntStream;
+
+public class SplittingCosts {
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void sourceSplittingIntStreamSequential() {
+        IntStream.rangeClosed(1, 100).reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void sourceSplittingIntStreamParallel() {
+        IntStream.rangeClosed(1, 100).parallel().reduce(0, Integer::sum);
+    }
+
+}

core-java-modules/core-java-streams-3/src/test/java/com/baeldung/streams/parallel/ForkJoinUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.streams.parallel;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ForkJoinPool;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ForkJoinUnitTest {
+
+    @Test
+    void givenSequentialStreamOfNumbers_whenReducingSumWithIdentityFive_thenResultIsCorrect() {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        int sum = listOfNumbers.stream().reduce(5, Integer::sum);
+        assertThat(sum).isEqualTo(15);
+    }
+
+    @Test
+    void givenParallelStreamOfNumbers_whenReducingSumWithIdentityFive_thenResultIsNotCorrect() {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        int sum = listOfNumbers.parallelStream().reduce(5, Integer::sum);
+        assertThat(sum).isNotEqualTo(15);
+    }
+
+    @Test
+    void givenParallelStreamOfNumbers_whenReducingSumWithIdentityZero_thenResultIsCorrect() {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        int sum = listOfNumbers.parallelStream().reduce(0, Integer::sum) + 5;
+        assertThat(sum).isEqualTo(15);
+    }
+
+    @Test
+    public void givenParallelStreamOfNumbers_whenUsingCustomThreadPool_thenResultIsCorrect()
+      throws InterruptedException, ExecutionException {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        ForkJoinPool customThreadPool = new ForkJoinPool(4);
+        int sum = customThreadPool.submit(
+          () -> listOfNumbers.parallelStream().reduce(0, Integer::sum)).get();
+        customThreadPool.shutdown();
+        assertThat(sum).isEqualTo(10);
+    }
+
+}

core-java-modules/core-java-string-operations-3/src/test/java/com/baeldung/splitkeepdelimiters/SplitAndKeepDelimitersUnitTest.java

@@ -0,0 +1,59 @@
+package com.baeldung.splitkeepdelimiters;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.regex.Pattern;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.jupiter.api.Test;
+
+import com.google.common.base.Splitter;
+
+public class SplitAndKeepDelimitersUnitTest {
+
+    private final String positivelookAheadRegex = "((?=@))";
+    private final String positivelookBehindRegex = "((?<=@))";
+    private final String positivelookAroundRegex = "((?=@)|(?<=@))";
+    private final String positiveLookAroundMultiDelimiterRegex = "((?=:|#|@)|(?<=:|#|@))";
+
+    private String text = "Hello@World@This@Is@A@Java@Program";
+    private String textMixed = "@HelloWorld@This:Is@A#Java#Program";
+    private String textMixed2 = "pg@no;10@hello;world@this;is@a#10words;Java#Program";
+
+    @Test
+    public void givenString_splitAndKeepDelimiters_using_javaLangString() {
+
+        assertThat(text.split(positivelookAheadRegex)).containsExactly("Hello", "@World", "@This", "@Is", "@A", "@Java", "@Program");
+
+        assertThat(text.split(positivelookBehindRegex)).containsExactly("Hello@", "World@", "This@", "Is@", "A@", "Java@", "Program");
+
+        assertThat(text.split(positivelookAroundRegex)).containsExactly("Hello", "@", "World", "@", "This", "@", "Is", "@", "A", "@", "Java", "@", "Program");
+
+        assertThat(textMixed.split(positiveLookAroundMultiDelimiterRegex)).containsExactly("@", "HelloWorld", "@", "This", ":", "Is", "@", "A", "#", "Java", "#", "Program");
+
+    }
+
+    @Test
+    public void givenString_splitAndKeepDelimiters_using_ApacheCommonsLang3StringUtils() {
+
+        assertThat(StringUtils.splitByCharacterType(textMixed2)).containsExactly("pg", "@", "no", ";", "10", "@", "hello", ";", "world", "@", "this", ";", "is", "@", "a", "#", "10", "words", ";", "J", "ava", "#", "P", "rogram");
+
+    }
+
+    @Test
+    public void givenString_splitAndKeepDelimiters_using_GuavaSplitter() {
+
+        assertThat(Splitter.onPattern(positivelookAroundRegex)
+            .splitToList(text)).containsExactly("Hello", "@", "World", "@", "This", "@", "Is", "@", "A", "@", "Java", "@", "Program");
+
+        assertThat(Splitter.on(Pattern.compile(positivelookAroundRegex))
+            .splitToList(text)).containsExactly("Hello", "@", "World", "@", "This", "@", "Is", "@", "A", "@", "Java", "@", "Program");
+
+        assertThat(Splitter.onPattern(positiveLookAroundMultiDelimiterRegex)
+            .splitToList(textMixed)).containsExactly("@", "HelloWorld", "@", "This", ":", "Is", "@", "A", "#", "Java", "#", "Program");
+
+        assertThat(Splitter.on(Pattern.compile(positiveLookAroundMultiDelimiterRegex))
+            .splitToList(textMixed)).containsExactly("@", "HelloWorld", "@", "This", ":", "Is", "@", "A", "#", "Java", "#", "Program");
+
+    }
+}

javaxval/src/test/java/com/baeldung/javaxval/bigdecimal/InvoiceUnitTest.java

@@ -1,18 +1,17 @@
 package com.baeldung.javaxval.bigdecimal;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
-import java.math.BigDecimal;
-import java.util.Set;
-
-import javax.validation.ConstraintViolation;
-import javax.validation.Validation;
-import javax.validation.Validator;
-
 import com.baeldung.javaxval.LocaleAwareUnitTest;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
+import javax.validation.ConstraintViolation;
+import javax.validation.Validation;
+import javax.validation.Validator;
+import java.math.BigDecimal;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
 public class InvoiceUnitTest extends LocaleAwareUnitTest {
 
     private static Validator validator;
@@ -24,41 +23,67 @@ public class InvoiceUnitTest extends LocaleAwareUnitTest {
     }
 
     @Test
-    public void whenPriceIntegerDigitLessThanThreeWithDecimalValue_thenShouldGiveConstraintViolations() {
-        Invoice invoice = new Invoice(new BigDecimal(10.21), "Book purchased");
+    public void whenLessThanThreeIntegerDigits_thenShouldNotGiveConstraintViolations() {
+        Invoice invoice = new Invoice(new BigDecimal("10.21"), "Book purchased");
         Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
-        assertThat(violations.size()).isEqualTo(1);
-        violations.forEach(action -> assertThat(action.getMessage()).isEqualTo("numeric value out of bounds (<3 digits>.<2 digits> expected)"));
+        assertThat(violations).isEmpty();
     }
 
     @Test
-    public void whenPriceIntegerDigitLessThanThreeWithIntegerValue_thenShouldNotGiveConstraintViolations() {
-        Invoice invoice = new Invoice(new BigDecimal(10), "Book purchased");
+    public void whenThreeIntegerDigits_thenShouldNotGiveConstraintViolations() {
+        Invoice invoice = new Invoice(new BigDecimal("102.21"), "Book purchased");
         Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
-        assertThat(violations.size()).isEqualTo(0);
+        assertThat(violations).isEmpty();
     }
 
     @Test
-    public void whenPriceIntegerDigitGreaterThanThree_thenShouldGiveConstraintViolations() {
-        Invoice invoice = new Invoice(new BigDecimal(1021.21), "Book purchased");
+    public void whenMoreThanThreeIntegerDigits_thenShouldGiveConstraintViolations() {
+        Invoice invoice = new Invoice(new BigDecimal("1021.21"), "Book purchased");
         Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
-        assertThat(violations.size()).isEqualTo(1);
-        violations.forEach(action -> assertThat(action.getMessage()).isEqualTo("numeric value out of bounds (<3 digits>.<2 digits> expected)"));
+        assertThat(violations).hasSize(1);
+        assertThat(violations)
+            .extracting("message")
+            .containsOnly("numeric value out of bounds (<3 digits>.<2 digits> expected)");
+    }
+
+    @Test
+    public void whenLessThanTwoFractionDigits_thenShouldNotGiveConstraintViolations() {
+        Invoice invoice = new Invoice(new BigDecimal("99.9"), "Book purchased");
+        Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
+        assertThat(violations).isEmpty();
+    }
+
+    @Test
+    public void whenTwoFractionDigits_thenShouldNotGiveConstraintViolations() {
+        Invoice invoice = new Invoice(new BigDecimal("99.99"), "Book purchased");
+        Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
+        assertThat(violations).isEmpty();
+    }
+
+    @Test
+    public void whenMoreThanTwoFractionDigits_thenShouldGiveConstraintViolations() {
+        Invoice invoice = new Invoice(new BigDecimal("99.999"), "Book purchased");
+        Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
+        assertThat(violations).hasSize(1);
+        assertThat(violations)
+            .extracting("message")
+            .containsOnly("numeric value out of bounds (<3 digits>.<2 digits> expected)");
     }
 
     @Test
     public void whenPriceIsZero_thenShouldGiveConstraintViolations() {
-        Invoice invoice = new Invoice(new BigDecimal(000.00), "Book purchased");
+        Invoice invoice = new Invoice(new BigDecimal("0.00"), "Book purchased");
         Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
-        assertThat(violations.size()).isEqualTo(1);
-        violations.forEach(action -> assertThat(action.getMessage()).isEqualTo("must be greater than 0.0"));
+        assertThat(violations).hasSize(1);
+        assertThat(violations)
+            .extracting("message")
+            .containsOnly("must be greater than 0.0");
     }
 
     @Test
     public void whenPriceIsGreaterThanZero_thenShouldNotGiveConstraintViolations() {
-        Invoice invoice = new Invoice(new BigDecimal(100.50), "Book purchased");
+        Invoice invoice = new Invoice(new BigDecimal("100.50"), "Book purchased");
         Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
-        assertThat(violations.size()).isEqualTo(0);
+        assertThat(violations).isEmpty();
     }
-
 }

kubernetes/k8s-intro/README.md

@@ -16,3 +16,4 @@ If you get a valid response, then you're good to go.
 
 - [Paging and Async Calls with the Kubernetes API](https://www.baeldung.com/java-kubernetes-paging-async)
 - [Using Watch with the Kubernetes API](https://www.baeldung.com/java-kubernetes-watch)
+- [Using Namespaces and Selectors With the Kubernetes Java API](https://www.baeldung.com/java-kubernetes-namespaces-selectors)

kubernetes/k8s-intro/src/k8s/create-http-server.yml

@@ -0,0 +1,58 @@
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: ns1
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: ns2
+---
+  apiVersion: apps/v1
+  kind: Deployment
+  metadata:
+    name: httpd
+    namespace: ns1
+    labels:
+      app: httpd
+      version: "1"
+  spec:
+    replicas: 3
+    selector:
+      matchLabels:
+        app: httpd
+    template:
+      metadata:
+        labels:
+          app: httpd
+      spec:
+        containers:
+        - name: main
+          image: httpd:alpine
+          ports:
+          - containerPort: 80
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: httpd
+  namespace: ns2
+  labels:
+    app: httpd
+    version: "2"
+    foo: bar
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: httpd
+  template:
+    metadata:
+      labels:
+        app: httpd
+    spec:
+      containers:
+      - name: main
+        image: httpd:alpine
+        ports:
+        - containerPort: 80

kubernetes/k8s-intro/src/main/java/com/baeldung/kubernetes/intro/ListPodsWithFieldSelectors.java

@@ -0,0 +1,68 @@
+/**
+ * 
+ */
+package com.baeldung.kubernetes.intro;
+
+
+import java.util.concurrent.TimeUnit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import io.kubernetes.client.openapi.ApiClient;
+import io.kubernetes.client.openapi.apis.CoreV1Api;
+import io.kubernetes.client.openapi.models.V1NodeList;
+import io.kubernetes.client.openapi.models.V1PodList;
+import io.kubernetes.client.util.Config;
+import okhttp3.OkHttpClient;
+import okhttp3.logging.HttpLoggingInterceptor;
+
+/**
+ * @author Philippe
+ *
+ */
+public class ListPodsWithFieldSelectors {
+    
+    private static final Logger log = LoggerFactory.getLogger(ListPodsWithFieldSelectors.class);
+
+    /**
+     * @param args
+     */
+    public static void main(String[] args) throws Exception {
+        
+        ApiClient client  = Config.defaultClient();
+        HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor(message -> log.info(message));
+        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
+        OkHttpClient newClient = client.getHttpClient()
+          .newBuilder()
+          .addInterceptor(interceptor)
+          .readTimeout(0, TimeUnit.SECONDS)
+          .build();
+        
+        client.setHttpClient(newClient);
+        CoreV1Api api = new CoreV1Api(client);
+        
+        String fs = createSelector(args);
+        V1PodList items = api.listPodForAllNamespaces(null, null, fs, null, null, null, null, null, 10, false);
+        items.getItems()
+          .stream()
+          .map((pod) -> pod.getMetadata().getName() )
+          .forEach((name) -> System.out.println("name=" + name));
+        
+    }
+
+    private static String createSelector(String[] args) {
+
+        StringBuilder b = new StringBuilder();
+        for( int i =  0 ; i < args.length; i++ ) {
+            if( b.length() > 0 ) {
+                b.append(',');
+            }
+            
+            b.append(args[i]);
+        }
+        
+        return b.toString();
+    }
+
+}

kubernetes/k8s-intro/src/main/java/com/baeldung/kubernetes/intro/ListPodsWithLabelSelectors.java

@@ -0,0 +1,68 @@
+/**
+ * 
+ */
+package com.baeldung.kubernetes.intro;
+
+
+import java.util.concurrent.TimeUnit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import io.kubernetes.client.openapi.ApiClient;
+import io.kubernetes.client.openapi.apis.CoreV1Api;
+import io.kubernetes.client.openapi.models.V1NodeList;
+import io.kubernetes.client.openapi.models.V1PodList;
+import io.kubernetes.client.util.Config;
+import okhttp3.OkHttpClient;
+import okhttp3.logging.HttpLoggingInterceptor;
+
+/**
+ * @author Philippe
+ *
+ */
+public class ListPodsWithLabelSelectors {
+    
+    private static final Logger log = LoggerFactory.getLogger(ListPodsWithLabelSelectors.class);
+
+    /**
+     * @param args
+     */
+    public static void main(String[] args) throws Exception {
+        
+        ApiClient client  = Config.defaultClient();
+        HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor(message -> log.info(message));
+        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
+        OkHttpClient newClient = client.getHttpClient()
+          .newBuilder()
+          .addInterceptor(interceptor)
+          .readTimeout(0, TimeUnit.SECONDS)
+          .build();
+        
+        client.setHttpClient(newClient);
+        CoreV1Api api = new CoreV1Api(client);
+
+        String selector = createSelector(args);
+        V1PodList items = api.listPodForAllNamespaces(null, null, null, selector, null, null, null, null, 10, false);
+        items.getItems()
+          .stream()
+          .map((pod) -> pod.getMetadata().getName() )
+          .forEach((name) -> System.out.println("name=" + name));
+        
+    }
+    
+    private static String createSelector(String[] args) {
+
+        StringBuilder b = new StringBuilder();
+        for( int i =  0 ; i < args.length; i++ ) {
+            if( b.length() > 0 ) {
+                b.append(',');
+            }
+            
+            b.append(args[i]);
+        }
+        
+        return b.toString();
+    }
+    
+}

kubernetes/k8s-intro/src/main/java/com/baeldung/kubernetes/intro/ListPodsWithNamespaces.java

@@ -0,0 +1,52 @@
+/**
+ * 
+ */
+package com.baeldung.kubernetes.intro;
+
+
+import java.util.concurrent.TimeUnit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import io.kubernetes.client.openapi.ApiClient;
+import io.kubernetes.client.openapi.apis.CoreV1Api;
+import io.kubernetes.client.openapi.models.V1NodeList;
+import io.kubernetes.client.openapi.models.V1PodList;
+import io.kubernetes.client.util.Config;
+import okhttp3.OkHttpClient;
+import okhttp3.logging.HttpLoggingInterceptor;
+
+/**
+ * @author Philippe
+ *
+ */
+public class ListPodsWithNamespaces {
+    
+    private static final Logger log = LoggerFactory.getLogger(ListPodsWithNamespaces.class);
+
+    /**
+     * @param args
+     */
+    public static void main(String[] args) throws Exception {
+        
+        ApiClient client  = Config.defaultClient();
+        HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor(message -> log.info(message));
+        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
+        OkHttpClient newClient = client.getHttpClient()
+          .newBuilder()
+          .addInterceptor(interceptor)
+          .readTimeout(0, TimeUnit.SECONDS)
+          .build();
+        
+        client.setHttpClient(newClient);
+        CoreV1Api api = new CoreV1Api(client);
+        String namespace = "ns1";
+        V1PodList items = api.listNamespacedPod(namespace,null, null, null, null, null, null, null, null, 10, false);
+        items.getItems()
+          .stream()
+          .map((pod) -> pod.getMetadata().getName() )
+          .forEach((name) -> System.out.println("name=" + name));
+        
+    }
+}

kubernetes/k8s-intro/src/test/java/com/baeldung/kubernetes/intro/ListPodsWithFieldSelectorsLiveTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.kubernetes.intro;
+
+import org.junit.jupiter.api.Test;
+
+class ListPodsWithFieldSelectorsLiveTest {
+    @Test
+    void givenEqualitySelector_whenListPodsWithFieldSelectors_thenSuccess()  throws Exception {
+        ListPodsWithFieldSelectors.main(new String[] {
+            "metadata.namespace=ns1"
+        });
+    }
+
+    @Test
+    void givenInequalitySelector_whenListPodsWithFieldSelectors_thenSuccess()  throws Exception {
+        ListPodsWithFieldSelectors.main(new String[] {
+            "metadata.namespace!=ns1"
+        });
+    }
+    
+    @Test
+    void givenChainedSelector_whenListPodsWithFieldSelectors_thenSuccess()  throws Exception {
+        ListPodsWithFieldSelectors.main(new String[] {
+            "metadata.namespace=ns1",
+            "status.phase=Running"
+        });
+    }
+}

kubernetes/k8s-intro/src/test/java/com/baeldung/kubernetes/intro/ListPodsWithLabelSelectorsLiveTest.java

@@ -0,0 +1,55 @@
+package com.baeldung.kubernetes.intro;
+
+import org.junit.jupiter.api.Test;
+
+class ListPodsWithLabelSelectorsLiveTest {
+    @Test
+    void givenEqualitySelector_whenListPodsWithLabelSelectors_thenSuccess()  throws Exception {
+        ListPodsWithLabelSelectors.main(new String[] {
+          "app=httpd"
+        });
+    }
+    
+    @Test
+    void givenInqualitySelector_whenListPodsWithLabelSelectors_thenSuccess()  throws Exception {
+        ListPodsWithLabelSelectors.main(new String[] {
+          "app!=httpd"
+        });
+    }
+
+    @Test
+    void givenInSetSelector_whenListPodsWithLabelSelectors_thenSuccess()  throws Exception {
+        ListPodsWithLabelSelectors.main(new String[] {
+          "app in (httpd,test)"
+        });
+    }
+
+    @Test
+    void givenNotInSetSelector_whenListPodsWithLabelSelectors_thenSuccess()  throws Exception {
+        ListPodsWithLabelSelectors.main(new String[] {
+          "app notin (httpd)"
+        });
+    }
+
+    @Test
+    void givenLabelPresentSelector_whenListPodsWithLabelSelectors_thenSuccess()  throws Exception {
+        ListPodsWithLabelSelectors.main(new String[] {
+          "app"
+        });
+    }
+    
+    @Test
+    void givenLabelNotPresentSelector_whenListPodsWithLabelSelectors_thenSuccess()  throws Exception {
+        ListPodsWithLabelSelectors.main(new String[] {
+          "!app"
+        });
+    }
+    
+    @Test
+    void givenChainedSelector_whenListPodsWithLabelSelectors_thenSuccess()  throws Exception {
+        ListPodsWithLabelSelectors.main(new String[] {
+          "app=httpd",
+          "!foo"
+        });
+    }
+}

libraries-http-2/README.md

@@ -8,5 +8,6 @@ This module contains articles about HTTP libraries.
 - [Decode an OkHttp JSON Response](https://www.baeldung.com/okhttp-json-response)
 - [Retrofit 2 – Dynamic URL](https://www.baeldung.com/retrofit-dynamic-url)
 - [Adding Interceptors in OkHTTP](https://www.baeldung.com/java-okhttp-interceptors)
+- [A Guide to Events in OkHTTP](https://www.baeldung.com/java-okhttp-events)
 - More articles [[<-- prev]](/libraries-http)
 

libraries-http-2/src/main/java/com/baeldung/okhttp/events/EventTimer.java

@@ -0,0 +1,156 @@
+package com.baeldung.okhttp.events;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.Proxy;
+import java.util.List;
+
+import okhttp3.Call;
+import okhttp3.Connection;
+import okhttp3.EventListener;
+import okhttp3.Handshake;
+import okhttp3.HttpUrl;
+import okhttp3.Protocol;
+import okhttp3.Request;
+import okhttp3.Response;
+
+public class EventTimer extends EventListener {
+
+    private long start;
+
+    private void logTimedEvent(String name) {
+        long now = System.nanoTime();
+        if (name.equals("callStart")) {
+            start = now;
+        }
+        long elapsedNanos = now - start;
+        System.out.printf("%.3f %s%n", elapsedNanos / 1000000000d, name);
+    }
+
+    @Override
+    public void callStart(Call call) {
+        logTimedEvent("callStart");
+    }
+
+    @Override
+    public void proxySelectStart(Call call, HttpUrl url) {
+        logTimedEvent("proxySelectStart");
+    }
+
+    @Override
+    public void proxySelectEnd(Call call, HttpUrl url, List<Proxy> proxies) {
+        logTimedEvent("proxySelectEnd");
+    }
+
+    @Override
+    public void dnsStart(Call call, String domainName) {
+        logTimedEvent("dnsStart");
+    }
+
+    @Override
+    public void dnsEnd(Call call, String domainName, List<InetAddress> inetAddressList) {
+        logTimedEvent("dnsEnd");
+    }
+
+    @Override
+    public void connectStart(Call call, InetSocketAddress inetSocketAddress, Proxy proxy) {
+        logTimedEvent("connectStart");
+    }
+
+    @Override
+    public void secureConnectStart(Call call) {
+        logTimedEvent("secureConnectStart");
+    }
+
+    @Override
+    public void secureConnectEnd(Call call, Handshake handshake) {
+        logTimedEvent("secureConnectEnd");
+    }
+
+    @Override
+    public void connectEnd(Call call, InetSocketAddress inetSocketAddress, Proxy proxy, Protocol protocol) {
+        logTimedEvent("connectEnd");
+    }
+
+    @Override
+    public void connectFailed(Call call, InetSocketAddress inetSocketAddress, Proxy proxy, Protocol protocol, IOException ioe) {
+        logTimedEvent("connectFailed");
+    }
+
+    @Override
+    public void connectionAcquired(Call call, Connection connection) {
+        logTimedEvent("connectionAcquired");
+    }
+
+    @Override
+    public void connectionReleased(Call call, Connection connection) {
+        logTimedEvent("connectionReleased");
+    }
+
+    @Override
+    public void requestHeadersStart(Call call) {
+        logTimedEvent("requestHeadersStart");
+    }
+
+    @Override
+    public void requestHeadersEnd(Call call, Request request) {
+        logTimedEvent("requestHeadersEnd");
+    }
+
+    @Override
+    public void requestBodyStart(Call call) {
+        logTimedEvent("requestBodyStart");
+    }
+
+    @Override
+    public void requestBodyEnd(Call call, long byteCount) {
+        logTimedEvent("requestBodyEnd");
+    }
+
+    @Override
+    public void requestFailed(Call call, IOException ioe) {
+        logTimedEvent("requestFailed");
+    }
+
+    @Override
+    public void responseHeadersStart(Call call) {
+        logTimedEvent("responseHeadersStart");
+    }
+
+    @Override
+    public void responseHeadersEnd(Call call, Response response) {
+        logTimedEvent("responseHeadersEnd");
+    }
+
+    @Override
+    public void responseBodyStart(Call call) {
+        logTimedEvent("responseBodyStart");
+    }
+
+    @Override
+    public void responseBodyEnd(Call call, long byteCount) {
+        logTimedEvent("responseBodyEnd");
+    }
+
+    @Override
+    public void responseFailed(Call call, IOException ioe) {
+        logTimedEvent("responseFailed");
+    }
+
+    @Override
+    public void callEnd(Call call) {
+        logTimedEvent("callEnd");
+    }
+
+    @Override
+    public void callFailed(Call call, IOException ioe) {
+        logTimedEvent("callFailed");
+    }
+
+    @Override
+    public void canceled(Call call) {
+        logTimedEvent("canceled");
+    }
+
+}

libraries-http-2/src/main/java/com/baeldung/okhttp/events/SimpleLogEventsListener.java

@@ -0,0 +1,37 @@
+package com.baeldung.okhttp.events;
+
+import java.time.LocalDateTime;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import okhttp3.Call;
+import okhttp3.EventListener;
+import okhttp3.Request;
+import okhttp3.Response;
+
+public class SimpleLogEventsListener extends EventListener {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(SimpleLogEventsListener.class);
+
+    @Override
+    public void callStart(Call call) {
+        LOGGER.info("callStart at {}", LocalDateTime.now());
+    }
+
+    @Override
+    public void requestHeadersEnd(Call call, Request request) {
+        LOGGER.info("requestHeadersEnd at {} with headers {}", LocalDateTime.now(), request.headers());
+    }
+
+    @Override
+    public void responseHeadersEnd(Call call, Response response) {
+        LOGGER.info("responseHeadersEnd at {} with headers {}", LocalDateTime.now(), response.headers());
+    }
+
+    @Override
+    public void callEnd(Call call) {
+        LOGGER.info("callEnd at {}", LocalDateTime.now());
+    }
+
+}

libraries-http-2/src/test/java/com/baeldung/okhttp/events/EventTimerLiveTest.java

@@ -0,0 +1,31 @@
+package com.baeldung.okhttp.events;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.Response;
+
+public class EventTimerLiveTest {
+
+    @Test
+    public void givenSimpleEventTimer_whenRequestSent_thenCallsLogged() throws IOException {
+        
+        OkHttpClient client = new OkHttpClient.Builder()
+            .eventListener(new EventTimer())
+            .build();
+
+        Request request = new Request.Builder()
+            .url("https://www.baeldung.com/")
+            .build();
+
+        try (Response response = client.newCall(request).execute()) {
+            assertEquals("Response code should be: ", 200, response.code());
+        }
+    }
+
+}

libraries-http-2/src/test/java/com/baeldung/okhttp/events/LogEventsListenerIntegrationTest.java

@@ -0,0 +1,53 @@
+package com.baeldung.okhttp.events;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import java.net.SocketTimeoutException;
+
+import org.junit.Rule;
+import org.junit.Test;
+
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.Response;
+import okhttp3.mockwebserver.MockResponse;
+import okhttp3.mockwebserver.MockWebServer;
+
+public class LogEventsListenerIntegrationTest {
+    
+    @Rule
+    public MockWebServer server = new MockWebServer();
+
+    @Test
+    public void givenSimpleEventLogger_whenRequestSent_thenCallsLogged() throws IOException {
+        server.enqueue(new MockResponse().setBody("Hello Baeldung Readers!"));
+        
+        OkHttpClient client = new OkHttpClient.Builder()
+            .eventListener(new SimpleLogEventsListener())
+            .build();
+
+        Request request = new Request.Builder()
+            .url(server.url("/"))
+            .build();
+
+        try (Response response = client.newCall(request).execute()) {
+            assertEquals("Response code should be: ", 200, response.code());
+            assertEquals("Body should be: ", "Hello Baeldung Readers!", response.body().string());
+        }
+    }
+    
+    @Test (expected = SocketTimeoutException.class)
+    public void givenConnectionError_whenRequestSent_thenFailedCallsLogged() throws IOException {
+        OkHttpClient client = new OkHttpClient.Builder()
+            .eventListener(new EventTimer())
+            .build();
+
+        Request request = new Request.Builder()
+            .url(server.url("/"))
+            .build();
+
+        client.newCall(request).execute();
+    }
+
+}

maven-modules/maven-copy-files/copy-rename-maven-plugin/pom.xml

@@ -0,0 +1,92 @@
+<?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>
+        <artifactId>maven-copy-files</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <groupId>org.baeldung</groupId>
+    <artifactId>copy-rename-maven-plugin</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <name>copy-rename-maven-plugin</name>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.7</maven.compiler.source>
+        <maven.compiler.target>1.7</maven.compiler.target>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.11</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>com.coderplus.maven.plugins</groupId>
+                <artifactId>copy-rename-maven-plugin</artifactId>
+                <version>1.0</version>
+                <executions>
+                    <execution>
+                        <id>copy-file</id>
+                        <phase>generate-sources</phase>
+                        <goals>
+                            <goal>copy</goal>
+                        </goals>
+                        <configuration>
+                            <sourceFile>source-files/foo.txt</sourceFile>
+                            <destinationFile>target/destination-folder/foo.txt</destinationFile>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+        <pluginManagement>
+            <!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
+            <plugins>
+                <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
+                <plugin>
+                    <artifactId>maven-clean-plugin</artifactId>
+                    <version>3.1.0</version>
+                </plugin>
+                <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
+                <plugin>
+                    <artifactId>maven-resources-plugin</artifactId>
+                    <version>3.0.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>3.8.0</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-surefire-plugin</artifactId>
+                    <version>2.22.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-jar-plugin</artifactId>
+                    <version>3.0.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-install-plugin</artifactId>
+                    <version>2.5.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-deploy-plugin</artifactId>
+                    <version>2.8.2</version>
+                </plugin>
+                <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
+                <plugin>
+                    <artifactId>maven-site-plugin</artifactId>
+                    <version>3.7.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-project-info-reports-plugin</artifactId>
+                    <version>3.0.0</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+</project>

maven-modules/maven-copy-files/copy-rename-maven-plugin/source-files/foo.txt

@@ -0,0 +1 @@
+Copy File Example

maven-modules/maven-copy-files/copy-rename-maven-plugin/src/test/java/org/baeldung/CopyFileUnitTest.java

@@ -0,0 +1,16 @@
+package org.baeldung;
+
+import org.junit.Test;
+
+import java.io.File;
+
+import static org.junit.Assert.assertEquals;
+
+public class CopyFileUnitTest {
+
+    @Test
+    public void whenCopyingAFileFromSourceToDestination_thenFileShouldBeInDestination() {
+        File destinationFile = new File("target/destination-folder/foo.txt");
+        assertEquals(true, destinationFile.exists());
+    }
+}

maven-modules/maven-copy-files/maven-antrun-plugin/pom.xml

@@ -0,0 +1,94 @@
+<?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>
+        <artifactId>maven-copy-files</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <groupId>org.baeldung</groupId>
+    <artifactId>maven-antrun-plugin</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <name>maven-antrun-plugin</name>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.7</maven.compiler.source>
+        <maven.compiler.target>1.7</maven.compiler.target>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.11</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <artifactId>maven-antrun-plugin</artifactId>
+                <version>3.0.0</version>
+                <executions>
+                    <execution>
+                        <phase>generate-sources</phase>
+                        <configuration>
+                            <target>
+                                <mkdir dir="${basedir}/target/destination-folder" />
+                                <copy todir="${basedir}/target/destination-folder">
+                                    <fileset dir="${basedir}/source-files" includes="foo.txt" />
+                                </copy>
+                            </target>
+                        </configuration>
+                        <goals>
+                            <goal>run</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+        <pluginManagement>
+            <!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
+            <plugins>
+                <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
+                <plugin>
+                    <artifactId>maven-clean-plugin</artifactId>
+                    <version>3.1.0</version>
+                </plugin>
+                <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
+                <plugin>
+                    <artifactId>maven-resources-plugin</artifactId>
+                    <version>3.0.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>3.8.0</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-surefire-plugin</artifactId>
+                    <version>2.22.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-jar-plugin</artifactId>
+                    <version>3.0.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-install-plugin</artifactId>
+                    <version>2.5.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-deploy-plugin</artifactId>
+                    <version>2.8.2</version>
+                </plugin>
+                <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
+                <plugin>
+                    <artifactId>maven-site-plugin</artifactId>
+                    <version>3.7.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-project-info-reports-plugin</artifactId>
+                    <version>3.0.0</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+</project>

maven-modules/maven-copy-files/maven-antrun-plugin/source-files/foo.txt

@@ -0,0 +1 @@
+Copy File Example

maven-modules/maven-copy-files/maven-antrun-plugin/src/test/java/org/baeldung/CopyFileUnitTest.java

@@ -0,0 +1,16 @@
+package org.baeldung;
+
+import org.junit.Test;
+
+import java.io.File;
+
+import static org.junit.Assert.assertEquals;
+
+public class CopyFileUnitTest {
+
+    @Test
+    public void whenCopyingAFileFromSourceToDestination_thenFileShouldBeInDestination() {
+        File destinationFile = new File("target/destination-folder/foo.txt");
+        assertEquals(true, destinationFile.exists());
+    }
+}

maven-modules/maven-copy-files/maven-resources-plugin/pom.xml

@@ -0,0 +1,92 @@
+<?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>
+        <artifactId>maven-copy-files</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <groupId>org.baeldung</groupId>
+    <artifactId>maven-resources-plugin</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <name>maven-resoures-plugin</name>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.7</maven.compiler.source>
+        <maven.compiler.target>1.7</maven.compiler.target>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.11</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <pluginManagement>
+            <!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
+            <plugins>
+                <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
+                <plugin>
+                    <artifactId>maven-clean-plugin</artifactId>
+                    <version>3.1.0</version>
+                </plugin>
+                <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
+                <plugin>
+                    <artifactId>maven-resources-plugin</artifactId>
+                    <version>3.0.2</version>
+                    <executions>
+                        <execution>
+                            <id>copy-resource-one</id>
+                            <phase>generate-sources</phase>
+                            <goals>
+                                <goal>copy-resources</goal>
+                            </goals>
+                            <configuration>
+                                <outputDirectory>${basedir}/target/destination-folder</outputDirectory>
+                                <resources>
+                                    <resource>
+                                        <directory>source-files</directory>
+                                        <includes>
+                                            <include>foo.txt</include>
+                                        </includes>
+                                    </resource>
+                                </resources>
+                            </configuration>
+                        </execution>
+                    </executions>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>3.8.0</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-surefire-plugin</artifactId>
+                    <version>2.22.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-jar-plugin</artifactId>
+                    <version>3.0.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-install-plugin</artifactId>
+                    <version>2.5.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-deploy-plugin</artifactId>
+                    <version>2.8.2</version>
+                </plugin>
+                <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
+                <plugin>
+                    <artifactId>maven-site-plugin</artifactId>
+                    <version>3.7.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-project-info-reports-plugin</artifactId>
+                    <version>3.0.0</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+</project>

maven-modules/maven-copy-files/maven-resources-plugin/source-files/foo.txt

@@ -0,0 +1 @@
+Copy File Example

maven-modules/maven-copy-files/maven-resources-plugin/src/test/java/org/baeldung/CopyFileUnitTest.java

@@ -0,0 +1,16 @@
+package org.baeldung;
+
+import org.junit.Test;
+
+import java.io.File;
+
+import static org.junit.Assert.assertEquals;
+
+public class CopyFileUnitTest {
+
+    @Test
+    public void whenCopyingAFileFromSourceToDestination_thenFileShouldBeInDestination() {
+        File destinationFile = new File("target/destination-folder/foo.txt");
+        assertEquals(true, destinationFile.exists());
+    }
+}

maven-modules/maven-copy-files/pom.xml

@@ -0,0 +1,80 @@
+<?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>
+        <artifactId>maven-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+    <groupId>com.baeldung</groupId>
+    <artifactId>maven-copy-files</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>pom</packaging>
+    <name>maven-copy-files</name>
+    <!-- FIXME change it to the project's website -->
+    <url>http://www.example.com</url>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.7</maven.compiler.source>
+        <maven.compiler.target>1.7</maven.compiler.target>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.11</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <pluginManagement>
+            <!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
+            <plugins>
+                <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
+                <plugin>
+                    <artifactId>maven-clean-plugin</artifactId>
+                    <version>3.1.0</version>
+                </plugin>
+                <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
+                <plugin>
+                    <artifactId>maven-resources-plugin</artifactId>
+                    <version>3.0.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>3.8.0</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-surefire-plugin</artifactId>
+                    <version>2.22.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-jar-plugin</artifactId>
+                    <version>3.0.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-install-plugin</artifactId>
+                    <version>2.5.2</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-deploy-plugin</artifactId>
+                    <version>2.8.2</version>
+                </plugin>
+                <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
+                <plugin>
+                    <artifactId>maven-site-plugin</artifactId>
+                    <version>3.7.1</version>
+                </plugin>
+                <plugin>
+                    <artifactId>maven-project-info-reports-plugin</artifactId>
+                    <version>3.0.0</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+    <modules>
+        <module>maven-resources-plugin</module>
+        <module>maven-antrun-plugin</module>
+        <module>copy-rename-maven-plugin</module>
+    </modules>
+</project>

maven-modules/maven-printing-plugins/.gitignore

@@ -0,0 +1 @@
+logs/

maven-modules/maven-printing-plugins/pom.xml

@@ -0,0 +1,85 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>maven-printing-plugins</artifactId>
+    <name>maven-printing-plugins</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../..</relativePath>
+    </parent>
+
+    <build>
+        <plugins>
+            <plugin>
+                <artifactId>maven-antrun-plugin</artifactId>
+                <version>3.0.0</version>
+                <executions>
+                    <execution>
+                        <id>antrun-plugin</id>
+                        <phase>validate</phase>
+                        <goals>
+                            <goal>run</goal>
+                        </goals>
+                        <configuration>
+                            <target>
+                                <echo message="Hello, world"/>
+                                <echo message="Embed a line break: ${line.separator}"/>
+                                <echo message="Build dir: ${project.build.directory}" level="info"/>
+                                <echo file="${basedir}/logs/log-ant-run.txt" append="true"
+                                      message="Save to file!"/>
+                            </target>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>com.github.ekryd.echo-maven-plugin</groupId>
+                <artifactId>echo-maven-plugin</artifactId>
+                <version>1.3.2</version>
+                <executions>
+                    <execution>
+                        <id>echo-maven-plugin-1</id>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>echo</goal>
+                        </goals>
+                        <configuration>
+                            <message>Hello, world</message>
+                            <message>Embed a line break: ${line.separator}</message>
+                            <message>ArtifactId is ${project.artifactId}</message>
+                            <level>INFO</level>
+                            <toFile>/logs/log-echo.txt</toFile>
+                            <append>true</append>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.codehaus.gmaven</groupId>
+                <artifactId>groovy-maven-plugin</artifactId>
+                <version>2.1.1</version>
+                <executions>
+                    <execution>
+                        <phase>validate</phase>
+                        <goals>
+                            <goal>execute</goal>
+                        </goals>
+                        <configuration>
+                            <source>
+                                log.info('Test message: {}', 'Hello, World!')
+                                log.info('Embed a line break {}', System.lineSeparator())
+                                log.info('ArtifactId is:  ${project.artifactId}')
+                                log.warn('Message only in debug mode')
+                            </source>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

maven-modules/pom.xml

@@ -16,6 +16,7 @@
 
     <modules>
         <!-- <module>compiler-plugin-java-9</module> --> <!-- We haven't upgraded to java 9. -->
+	<module>maven-copy-files</module>
         <module>maven-custom-plugin</module>
         <module>maven-exec-plugin</module>
         <module>maven-integration-test</module>
@@ -30,6 +31,7 @@
         <module>version-collision</module>
         <module>version-overriding-plugins</module>
         <module>versions-maven-plugin</module>
+        <module>maven-printing-plugins</module>
     </modules>
 
-</project>
+</project>

netflix-modules/mantis/pom.xml

@@ -19,7 +19,6 @@
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter</artifactId>
-            <version>2.1.3.RELEASE</version>
         </dependency>
         <dependency>
             <groupId>io.mantisrx</groupId>
@@ -35,36 +34,31 @@
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
-            <version>2.10.2</version>
         </dependency>
         <dependency>
             <groupId>net.andreinc.mockneat</groupId>
             <artifactId>mockneat</artifactId>
-            <version>0.3.8</version>
+            <version>0.4.2</version>
         </dependency>
         <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
-            <version>1.18.12</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-webflux</artifactId>
-            <version>5.0.9.RELEASE</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>io.projectreactor.netty</groupId>
             <artifactId>reactor-netty</artifactId>
-            <version>0.9.12.RELEASE</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
-
     <repositories>
         <repository>
-            <id>SpringLibReleaseRepo</id>
-            <url>https://repo.spring.io/libs-release/</url>
+        	<id>jcenter</id>
+            <url>https://jcenter.bintray.com/</url>
         </repository>
     </repositories>
 

parent-boot-1/pom.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
+<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-boot-2/pom.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
+<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-java/pom.xml

@@ -1,8 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project
-        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-        xmlns="http://maven.apache.org/POM/4.0.0"
-        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="http://maven.apache.org/POM/4.0.0"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <artifactId>parent-java</artifactId>
     <version>0.0.1-SNAPSHOT</version>

parent-spring-4/pom.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
+<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-spring-5/pom.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
+<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>

patterns/design-patterns-behavioral/pom.xml

@@ -26,6 +26,11 @@
             <version>${lombok.version}</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.code.findbugs</groupId>
+            <artifactId>annotations</artifactId>
+            <version>${findbugs.annotations.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
@@ -41,6 +46,7 @@
 
     <properties>
         <intellij.annotations.version>16.0.2</intellij.annotations.version>
+        <findbugs.annotations.version>3.0.1</findbugs.annotations.version>
         <assertj-core.version>3.9.1</assertj-core.version>
     </properties>
 

patterns/design-patterns-behavioral/src/main/java/com/baeldung/nulls/FindBugsAnnotations.java

@@ -1,12 +1,12 @@
 package com.baeldung.nulls;
 
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
+import edu.umd.cs.findbugs.annotations.NonNull;
+import edu.umd.cs.findbugs.annotations.Nullable;
 
 public class FindBugsAnnotations {
 
-    public void accept(@NotNull Object param) {
+    public void accept(@NonNull Object param) {
         System.out.println(param.toString());
     }
 
@@ -14,7 +14,7 @@ public class FindBugsAnnotations {
         System.out.println("Printing " + param);
     }
 
-    @NotNull
+    @NonNull
     public Object process() throws Exception {
         Object result = doSomething();
         if (result == null) {

persistence-modules/hibernate-mapping/README.md

@@ -13,3 +13,4 @@ This module contains articles about Object-relational Mapping (ORM) with Hiberna
 - [Hibernate – Mapping Date and Time](https://www.baeldung.com/hibernate-date-time)
 - [Mapping LOB Data in Hibernate](https://www.baeldung.com/hibernate-lob)
 - [FetchMode in Hibernate](https://www.baeldung.com/hibernate-fetchmode)
+- [Mapping PostgreSQL Array With Hibernate](https://www.baeldung.com/java-hibernate-map-postgresql-array)

persistence-modules/hibernate-mapping/pom.xml

@@ -13,11 +13,22 @@
     </parent>
 
     <dependencies>
+        <dependency>
+            <groupId>org.postgresql</groupId>
+            <artifactId>postgresql</artifactId>
+            <version>${postgresql.version}</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.hibernate</groupId>
             <artifactId>hibernate-core</artifactId>
             <version>${hibernate.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.vladmihalcea</groupId>
+            <artifactId>hibernate-types-52</artifactId>
+            <version>${hibernate-types.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
@@ -64,7 +75,9 @@
     </dependencies>
 
     <properties>
+        <postgresql.version>42.2.20</postgresql.version>
         <hibernate.version>5.4.12.Final</hibernate.version>
+        <hibernate-types.version>2.10.4</hibernate-types.version>
         <assertj-core.version>3.8.0</assertj-core.version>
         <hibernate-validator.version>6.0.16.Final</hibernate-validator.version>
         <org.glassfish.javax.el.version>3.0.1-b11</org.glassfish.javax.el.version>

persistence-modules/hibernate-mapping/src/main/java/com/baeldung/hibernate/arraymapping/CustomIntegerArrayType.java

@@ -0,0 +1,85 @@
+package com.baeldung.hibernate.arraymapping;
+
+import java.io.Serializable;
+import java.sql.Array;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Types;
+import java.util.Arrays;
+
+import org.hibernate.HibernateException;
+import org.hibernate.engine.spi.SharedSessionContractImplementor;
+import org.hibernate.usertype.UserType;
+
+public class CustomIntegerArrayType implements UserType {
+
+    @Override
+    public int[] sqlTypes() {
+        return new int[]{Types.ARRAY};
+    }
+
+    @Override
+    public Class returnedClass() {
+        return Integer[].class;
+    }
+
+    @Override
+    public boolean equals(Object x, Object y) throws HibernateException {
+        if (x instanceof Integer[] && y instanceof Integer[]) {
+            return Arrays.deepEquals((Integer[])x, (Integer[])y);
+        } else {
+            return false;
+        }
+    }
+
+    @Override
+    public int hashCode(Object x) throws HibernateException {
+        return Arrays.hashCode((Integer[])x);
+    }
+
+    @Override
+    public Object nullSafeGet(ResultSet rs, String[] names, SharedSessionContractImplementor session, Object owner)
+      throws HibernateException, SQLException {
+        Array array = rs.getArray(names[0]);
+        return array != null ? array.getArray() : null;
+    }
+
+    @Override
+    public void nullSafeSet(PreparedStatement st, Object value, int index, SharedSessionContractImplementor session)
+      throws HibernateException, SQLException {
+        if (value != null && st != null) {
+            Array array = session.connection().createArrayOf("int", (Integer[])value);
+            st.setArray(index, array);
+        } else {
+            st.setNull(index, sqlTypes()[0]);
+        }
+    }
+
+    @Override
+    public Object deepCopy(Object value) throws HibernateException {
+        Integer[] a = (Integer[])value;
+        return Arrays.copyOf(a, a.length);
+    }
+
+    @Override
+    public boolean isMutable() {
+        return false;
+    }
+
+    @Override
+    public Serializable disassemble(Object value) throws HibernateException {
+        return (Serializable) value;
+    }
+
+    @Override
+    public Object assemble(Serializable cached, Object owner) throws HibernateException {
+        return cached;
+    }
+
+    @Override
+    public Object replace(Object original, Object target, Object owner) throws HibernateException {
+        return original;
+    }
+
+}

persistence-modules/hibernate-mapping/src/main/java/com/baeldung/hibernate/arraymapping/CustomStringArrayType.java

@@ -0,0 +1,85 @@
+package com.baeldung.hibernate.arraymapping;
+
+import java.io.Serializable;
+import java.sql.Array;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Types;
+import java.util.Arrays;
+
+import org.hibernate.HibernateException;
+import org.hibernate.engine.spi.SharedSessionContractImplementor;
+import org.hibernate.usertype.UserType;
+
+public class CustomStringArrayType implements UserType {
+
+    @Override
+    public int[] sqlTypes() {
+        return new int[]{Types.ARRAY};
+    }
+
+    @Override
+    public Class returnedClass() {
+        return String[].class;
+    }
+
+    @Override
+    public boolean equals(Object x, Object y) throws HibernateException {
+        if (x instanceof String[] && y instanceof String[]) {
+            return Arrays.deepEquals((String[])x, (String[])y);
+        } else {
+            return false;
+        }
+    }
+
+    @Override
+    public int hashCode(Object x) throws HibernateException {
+        return Arrays.hashCode((String[])x);
+    }
+
+    @Override
+    public Object nullSafeGet(ResultSet rs, String[] names, SharedSessionContractImplementor session, Object owner)
+      throws HibernateException, SQLException {
+        Array array = rs.getArray(names[0]);
+        return array != null ? array.getArray() : null;
+    }
+
+    @Override
+    public void nullSafeSet(PreparedStatement st, Object value, int index, SharedSessionContractImplementor session)
+      throws HibernateException, SQLException {
+        if (value != null && st != null) {
+            Array array = session.connection().createArrayOf("text", (String[])value);
+            st.setArray(index, array);
+        } else {
+            st.setNull(index, sqlTypes()[0]);
+        }
+    }
+
+    @Override
+    public Object deepCopy(Object value) throws HibernateException {
+        String[] a = (String[])value;
+        return Arrays.copyOf(a, a.length);
+    }
+
+    @Override
+    public boolean isMutable() {
+        return false;
+    }
+
+    @Override
+    public Serializable disassemble(Object value) throws HibernateException {
+        return (Serializable) value;
+    }
+
+    @Override
+    public Object assemble(Serializable cached, Object owner) throws HibernateException {
+        return cached;
+    }
+
+    @Override
+    public Object replace(Object original, Object target, Object owner) throws HibernateException {
+        return original;
+    }
+
+}

persistence-modules/hibernate-mapping/src/main/java/com/baeldung/hibernate/arraymapping/HibernateSessionUtil.java

@@ -0,0 +1,61 @@
+package com.baeldung.hibernate.arraymapping;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.net.URL;
+import java.util.Properties;
+
+import org.apache.commons.lang3.StringUtils;
+import org.hibernate.SessionFactory;
+import org.hibernate.boot.Metadata;
+import org.hibernate.boot.MetadataSources;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.service.ServiceRegistry;
+
+import com.baeldung.hibernate.arraymapping.User;
+
+public class HibernateSessionUtil {
+
+    private static SessionFactory sessionFactory;
+    private static String PROPERTY_FILE_NAME;
+
+    public static SessionFactory getSessionFactory() throws IOException {
+        return getSessionFactory(null);
+    }
+
+    public static SessionFactory getSessionFactory(String propertyFileName) throws IOException {
+        PROPERTY_FILE_NAME = propertyFileName;
+        if (sessionFactory == null) {
+            ServiceRegistry serviceRegistry = configureServiceRegistry();
+            sessionFactory = makeSessionFactory(serviceRegistry);
+        }
+        return sessionFactory;
+    }
+
+    private static SessionFactory makeSessionFactory(ServiceRegistry serviceRegistry) {
+        MetadataSources metadataSources = new MetadataSources(serviceRegistry);
+        metadataSources.addAnnotatedClass(User.class);
+
+        Metadata metadata = metadataSources.buildMetadata();
+        return metadata.getSessionFactoryBuilder()
+            .build();
+
+    }
+
+    private static ServiceRegistry configureServiceRegistry() throws IOException {
+        Properties properties = getProperties();
+        return new StandardServiceRegistryBuilder().applySettings(properties)
+            .build();
+    }
+
+    private static Properties getProperties() throws IOException {
+        Properties properties = new Properties();
+        URL propertiesURL = Thread.currentThread()
+            .getContextClassLoader()
+            .getResource(StringUtils.defaultString(PROPERTY_FILE_NAME, "hibernate_postgres.properties"));
+        try (FileInputStream inputStream = new FileInputStream(propertiesURL.getFile())) {
+            properties.load(inputStream);
+        }
+        return properties;
+    }
+}

persistence-modules/hibernate-mapping/src/main/java/com/baeldung/hibernate/arraymapping/User.java

@@ -0,0 +1,82 @@
+package com.baeldung.hibernate.arraymapping;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+
+import org.hibernate.annotations.Type;
+
+import com.vladmihalcea.hibernate.type.array.StringArrayType;
+
+import org.hibernate.annotations.*;
+
+@TypeDefs({
+    @TypeDef(
+        name = "string-array",
+        typeClass = StringArrayType.class
+        )
+})
+@Entity
+public class User {
+
+    @Id
+    private Long id;
+
+    private String name;
+
+    @Column(columnDefinition = "text[]")
+    @Type(type = "com.baeldung.hibernate.arraymapping.CustomStringArrayType")
+    private String[] roles;
+
+    @Column(columnDefinition = "int[]")
+    @Type(type = "com.baeldung.hibernate.arraymapping.CustomIntegerArrayType")
+    private Integer[] locations;
+
+    @Type(type = "string-array")
+    @Column(
+        name = "phone_numbers",
+        columnDefinition = "text[]"
+        )
+    private String[] phoneNumbers;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String[] getRoles() {
+        return roles;
+    }
+
+    public void setRoles(String[] roles) {
+        this.roles = roles;
+    }
+
+    public Integer[] getLocations() {
+        return locations;
+    }
+
+    public void setLocations(Integer[] locations) {
+        this.locations = locations;
+    }
+
+    public String[] getPhoneNumbers() {
+        return phoneNumbers;
+    }
+
+    public void setPhoneNumbers(String[] phoneNumbers) {
+        this.phoneNumbers = phoneNumbers;
+    }
+
+}

persistence-modules/hibernate-mapping/src/test/java/com/baeldung/hibernate/arraymapping/ArrayMappingIntegrationTest.java

@@ -0,0 +1,133 @@
+package com.baeldung.hibernate.arraymapping;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+
+import org.hibernate.HibernateException;
+import org.hibernate.Session;
+import org.hibernate.Transaction;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+
+public class ArrayMappingIntegrationTest {
+
+    private Session session;
+    private Transaction transaction;
+
+    @BeforeEach
+    public void setup() throws IOException {
+        try {
+            session = HibernateSessionUtil.getSessionFactory().openSession();
+            transaction = session.beginTransaction();
+
+            bootstrapData();
+
+        } catch (HibernateException | IOException e) {
+            System.out.println("Can't connect to a PostgreSQL DB");
+        }
+    }
+
+    @AfterEach
+    public void cleanup() {
+        if (null != session) { 
+            transaction.rollback();
+            session.close();
+        }
+    }
+
+    @Test
+    public void givenArrayMapping_whenQueried_thenReturnArraysFromDB() throws HibernateException, IOException {
+        if (null != session) {
+            User user = session.find(User.class, 1L);
+
+            assertEquals("john", user.getName());
+            assertEquals("superuser", user.getRoles()[0]);
+            assertEquals("admin", user.getRoles()[1]);
+            assertEquals(100, user.getLocations()[0]);
+            assertEquals(389, user.getLocations()[1]);
+            assertEquals("7000000000", user.getPhoneNumbers()[0]);
+            assertEquals("8000000000", user.getPhoneNumbers()[1]);
+        }
+    }
+
+    @Test
+    public void givenArrayMapping_whenArraysAreInserted_thenPersistInDB() throws HibernateException, IOException {
+        if (null != session) {
+            transaction = session.beginTransaction();
+
+            User user = new User();
+            user.setId(2L);
+            user.setName("smith");
+
+            String[] roles = {"admin", "employee"};
+            user.setRoles(roles);
+
+            Integer[] locations = {190, 578};
+            user.setLocations(locations);
+
+            session.persist(user);
+            session.flush();
+            session.clear();
+
+            transaction.commit();
+
+            User userDBObj = session.find(User.class, 2L);
+
+            assertEquals("smith", userDBObj.getName());
+            assertEquals("admin", userDBObj.getRoles()[0]);
+            assertEquals(578, userDBObj.getLocations()[1]);
+        }
+    }
+
+    @Test
+    public void givenArrayMapping_whenArrayIsUpdated_thenPersistInDB() throws HibernateException, IOException {
+        if (null != session) {
+            transaction = session.beginTransaction();
+
+            User user = session.find(User.class, 1L);
+
+            String[] updatedRoles = {"superuser", "superadmin"};
+            String[] updatedPhoneNumbers = {"9000000000"};
+
+            user.setRoles(updatedRoles);
+            user.setPhoneNumbers(updatedPhoneNumbers);
+
+            session.persist(user);
+            session.flush();
+            session.clear();
+
+            User userDBObj = session.find(User.class, 1L);
+
+            assertEquals("john", userDBObj.getName());
+            assertEquals("superadmin", userDBObj.getRoles()[1]);
+            assertEquals("9000000000", userDBObj.getPhoneNumbers()[0]);
+        }
+    }
+
+    public void bootstrapData() {
+        session.createQuery("delete from User").executeUpdate();
+
+        User user = new User();
+        user.setId(1L);
+        user.setName("john");
+
+        String[] roles = {"superuser", "admin"};
+        user.setRoles(roles);
+
+        Integer[] locations = {100, 389};
+        user.setLocations(locations);
+
+        String[] phoneNumbers = {"7000000000", "8000000000"};
+        user.setPhoneNumbers(phoneNumbers);
+
+        session.persist(user);
+        session.flush();
+        session.clear();
+
+        transaction.commit();
+    }
+
+}

persistence-modules/hibernate-mapping/src/test/resources/hibernate_postgres.properties

@@ -0,0 +1,14 @@
+hibernate.connection.driver_class=org.postgresql.Driver
+hibernate.connection.url=jdbc:postgresql://localhost:5432/postgres
+hibernate.connection.username=web
+hibernate.connection.autocommit=true
+jdbc.password=
+
+hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
+hibernate.show_sql=true
+hibernate.hbm2ddl.auto=none
+
+hibernate.c3p0.min_size=5
+hibernate.c3p0.max_size=20
+hibernate.c3p0.acquire_increment=5
+hibernate.c3p0.timeout=1800

persistence-modules/java-jpa-3/pom.xml

@@ -68,6 +68,12 @@
             <version>${assertj.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

persistence-modules/java-jpa-3/src/main/java/com/baeldung/jpa/IdGeneration/User.java

@@ -0,0 +1,41 @@
+package com.baeldung.jpa.IdGeneration;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class User {
+
+    @Id
+//    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private long id;
+    private String username;
+    private String password;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+}

persistence-modules/java-jpa-3/src/main/java/com/baeldung/jpa/IdGeneration/UserService.java

@@ -0,0 +1,19 @@
+package com.baeldung.jpa.IdGeneration;
+
+import javax.persistence.EntityManager;
+import javax.transaction.Transactional;
+
+public class UserService {
+
+    EntityManager entityManager;
+
+    public UserService(EntityManager entityManager) {
+        this.entityManager = entityManager;
+    }
+
+    @Transactional
+    public long saveUser(User user){
+        entityManager.persist(user);
+        return user.getId();
+    }
+}

persistence-modules/java-jpa-3/src/main/resources/META-INF/persistence.xml

@@ -97,4 +97,20 @@
             <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false"/>
         </properties>
     </persistence-unit>
+
+    <persistence-unit name="jpa-h2-id-generation">
+        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+        <class>com.baeldung.jpa.IdGeneration.User</class>
+        <exclude-unlisted-classes>true</exclude-unlisted-classes>
+        <properties>
+            <property name="javax.persistence.jdbc.driver" value="org.h2.Driver"/>
+            <property name="javax.persistence.jdbc.url" value="jdbc:h2:mem:idGen"/>
+            <property name="javax.persistence.jdbc.user" value="sa"/>
+            <property name="javax.persistence.jdbc.password" value=""/>
+            <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>
+            <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
+            <property name="hibernate.format_sql" value="true"/>
+            <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false"/>
+        </properties>
+    </persistence-unit>
 </persistence>

persistence-modules/java-jpa-3/src/test/java/com/baeldung/jpa/IdGeneration/IdGenerationIntegrationTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.jpa.IdGeneration;
+
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+import java.util.UUID;
+
+public class IdGenerationIntegrationTest {
+
+    private static EntityManager entityManager;
+    private static UserService service;
+
+    @BeforeClass
+    public static void setup() {
+        EntityManagerFactory factory = Persistence.createEntityManagerFactory("jpa-h2-id-generation");
+        entityManager = factory.createEntityManager();
+        service = new UserService(entityManager);
+    }
+
+    @Test
+    public void whenNewUserIsPersisted_thenEntityHasNoId() {
+        User user = new User();
+        user.setUsername("test");
+        user.setPassword(UUID.randomUUID().toString());
+
+        long index = service.saveUser(user);
+        Assert.assertEquals(0L, index);
+    }
+
+    @Test
+    public void whenTransactionIsControlled_thenEntityHasId() {
+        User user = new User();
+        user.setUsername("test");
+        user.setPassword(UUID.randomUUID().toString());
+
+        entityManager.getTransaction().begin();
+        long index = service.saveUser(user);
+        entityManager.getTransaction().commit();
+
+        Assert.assertEquals(2L, index);
+    }
+
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Address.java

@@ -0,0 +1,25 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.Embeddable;
+
+@Embeddable
+public class Address {
+    private String name;
+    private String city;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getCity() {
+        return city;
+    }
+
+    public void setCity(String city) {
+        this.city = city;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Brand.java

@@ -0,0 +1,29 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.Embeddable;
+import javax.persistence.Embedded;
+import java.time.LocalDate;
+
+@Embeddable
+public class Brand {
+    private String name;
+    private LocalDate foundationDate;
+    @Embedded
+    private Address address;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public LocalDate getFoundationDate() {
+        return foundationDate;
+    }
+
+    public void setFoundationDate(LocalDate foundationDate) {
+        this.foundationDate = foundationDate;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Car.java

@@ -0,0 +1,54 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.AttributeOverride;
+import javax.persistence.AttributeOverrides;
+import javax.persistence.Column;
+import javax.persistence.ElementCollection;
+import javax.persistence.Embedded;
+import javax.persistence.Entity;
+import java.util.Map;
+
+@Entity
+@AttributeOverride(name = "identifier", column = @Column(name = "VIN"))
+public class Car extends Vehicle {
+
+    private String model;
+    private String name;
+    @Embedded
+    @AttributeOverrides({
+      @AttributeOverride(name = "name", column = @Column(name = "BRAND_NAME", length = 5)),
+      @AttributeOverride(name = "address.name", column = @Column(name = "ADDRESS_NAME"))
+    })
+    private Brand brand;
+    @ElementCollection
+    @AttributeOverrides({
+      @AttributeOverride(name = "key.name", column = @Column(name = "OWNER_NAME")),
+      @AttributeOverride(name = "key.surname", column = @Column(name = "OWNER_SURNAME")),
+      @AttributeOverride(name = "value.name", column = @Column(name = "ADDRESS_NAME")),
+    })
+    Map<Owner, Address> owners;
+
+    public String getModel() {
+        return model;
+    }
+
+    public void setModel(String model) {
+        this.model = model;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Brand getBrand() {
+        return brand;
+    }
+
+    public void setBrand(Brand brand) {
+        this.brand = brand;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Owner.java

@@ -0,0 +1,25 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.Embeddable;
+
+@Embeddable
+public class Owner {
+    private String name;
+    private String surname;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Vehicle.java

@@ -0,0 +1,38 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.MappedSuperclass;
+
+@MappedSuperclass
+public class Vehicle {
+    @Id
+    @GeneratedValue
+    private Integer id;
+    private String identifier;
+    private Integer numberOfWheels;
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public String getIdentifier() {
+        return identifier;
+    }
+
+    public void setIdentifier(String identifier) {
+        this.identifier = identifier;
+    }
+
+    public Integer getNumberOfWheels() {
+        return numberOfWheels;
+    }
+
+    public void setNumberOfWheels(Integer numberOfWheels) {
+        this.numberOfWheels = numberOfWheels;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/repository/CarRepository.java

@@ -0,0 +1,7 @@
+package com.baeldung.attribute.override.repository;
+
+import com.baeldung.attribute.override.entity.Car;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface CarRepository extends JpaRepository<Car, Integer> {
+}

persistence-modules/spring-data-jpa-annotations/src/test/java/com/baeldung/attribute/override/AttributeOverrideIntegrationTest.java

@@ -0,0 +1,56 @@
+package com.baeldung.attribute.override;
+
+import com.baeldung.Application;
+import com.baeldung.attribute.override.entity.Address;
+import com.baeldung.attribute.override.entity.Brand;
+import com.baeldung.attribute.override.entity.Car;
+import com.baeldung.attribute.override.repository.CarRepository;
+import org.assertj.core.api.Assertions;
+import org.jetbrains.annotations.NotNull;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.LocalDate;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = { Application.class })
+public class AttributeOverrideIntegrationTest {
+
+    private static final LocalDate FORD_FOUNDATION_DATE = LocalDate.parse("1903-06-16");
+    @Autowired
+    CarRepository carRepository;
+
+    @Test
+    @Transactional
+    public void whenInsertingCar_thenEmbeddedAndMappedFieldsArePopulated() {
+
+        Car fordMustang = createMustang();
+
+        carRepository.save(fordMustang);
+        Car actualCar = carRepository.getOne(fordMustang.getId());
+
+        Assertions.assertThat(actualCar).isEqualTo(fordMustang);
+    }
+
+    @NotNull
+    private Car createMustang() {
+        Address address = new Address();
+        address.setName("Ford United States");
+        address.setCity("Dearborn");
+
+        Brand ford = new Brand();
+        ford.setName("Ford");
+        ford.setFoundationDate(FORD_FOUNDATION_DATE);
+
+        Car fordMustang = new Car();
+        fordMustang.setIdentifier("WP1AB29P88LA47599");
+        fordMustang.setModel("Ford");
+        fordMustang.setName("My car");
+        fordMustang.setBrand(ford);
+        return fordMustang;
+    }
+}

persistence-modules/spring-data-jpa-crud/src/main/java/com/baeldung/softdelete/Product.java

@@ -0,0 +1,68 @@
+package com.baeldung.softdelete;
+
+
+import java.io.Serializable;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+import org.hibernate.annotations.Filter;
+import org.hibernate.annotations.FilterDef;
+import org.hibernate.annotations.ParamDef;
+import org.hibernate.annotations.SQLDelete;
+
+@Entity
+@Table(name = "tbl_products")
+@SQLDelete(sql = "UPDATE tbl_products SET deleted = true WHERE id=?")
+@FilterDef(name = "deletedProductFilter", parameters = @ParamDef(name = "isDeleted", type = "boolean"))
+@Filter(name = "deletedProductFilter", condition = "deleted = :isDeleted")
+public class Product implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String name;
+
+    private double price;
+
+    private boolean deleted = Boolean.FALSE;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+
+    public void setPrice(double price) {
+        this.price = price;
+    }
+
+    public boolean isDeleted() {
+        return deleted;
+    }
+
+    public void setDeleted(boolean deleted) {
+        this.deleted = deleted;
+    }
+
+}

persistence-modules/spring-data-jpa-crud/src/main/java/com/baeldung/softdelete/ProductController.java

@@ -0,0 +1,34 @@
+package com.baeldung.softdelete;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/api/products")
+public class ProductController {
+
+    @Autowired
+    private ProductService productService;
+
+    @PostMapping
+    public Product createOne(@RequestBody Product product) {
+        return productService.create(product);
+    }
+
+    @DeleteMapping("/{id}")
+    public void removeOne(@PathVariable("id") Long id) {
+        productService.remove(id);
+    }
+
+    @GetMapping
+    public Iterable<Product> findAll(@RequestParam(value = "isDeleted", required = false, defaultValue = "false") boolean isDeleted) {
+        return productService.findAll(isDeleted);
+    }
+}

persistence-modules/spring-data-jpa-crud/src/main/java/com/baeldung/softdelete/ProductRepository.java

@@ -0,0 +1,7 @@
+package com.baeldung.softdelete;
+
+import org.springframework.data.repository.CrudRepository;
+
+public interface ProductRepository extends CrudRepository<Product, Long>{
+
+}

persistence-modules/spring-data-jpa-crud/src/main/java/com/baeldung/softdelete/ProductService.java

@@ -0,0 +1,35 @@
+package com.baeldung.softdelete;
+
+import javax.persistence.EntityManager;
+
+import org.hibernate.Filter;
+import org.hibernate.Session;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+@Service
+public class ProductService {
+
+    @Autowired
+    private ProductRepository productRepository;
+
+    @Autowired
+    private EntityManager entityManager;
+
+    public Product create(Product product) {
+        return productRepository.save(product);
+    }
+
+    public void remove(Long id){
+        productRepository.deleteById(id);
+    }
+
+    public Iterable<Product> findAll(boolean isDeleted){
+        Session session = entityManager.unwrap(Session.class);
+        Filter filter = session.enableFilter("deletedProductFilter");
+        filter.setParameter("isDeleted", isDeleted);
+        Iterable<Product> products =  productRepository.findAll();
+        session.disableFilter("deletedProductFilter");
+        return products;
+    }
+}

persistence-modules/spring-data-jpa-crud/src/main/resources/application.properties

@@ -5,10 +5,5 @@ spring.jpa.properties.hibernate.order_inserts=true
 spring.jpa.properties.hibernate.order_updates=true
 spring.jpa.properties.hibernate.generate_statistics=true
 
-# JPA-Schema-Generation
-# Use below configuration to generate database schema create commands based on the entity models
-# and export them into the create.sql file
-#spring.jpa.properties.javax.persistence.schema-generation.scripts.action=create
-#spring.jpa.properties.javax.persistence.schema-generation.scripts.create-target=create.sql
-#spring.jpa.properties.javax.persistence.schema-generation.scripts.create-source=metadata
-#spring.jpa.properties.hibernate.format_sql=true
+spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
+

pom.xml

@@ -623,6 +623,7 @@
                 <module>spring-boot-rest-2</module>
 
                 <module>spring-caching</module>
+                <module>spring-caching-2</module>
 
                 <module>spring-cloud</module>
                 <module>spring-cloud-bus</module>
@@ -1079,6 +1080,7 @@
                 <module>spring-boot-rest-2</module>
 
                 <module>spring-caching</module>
+                <module>spring-caching-2</module>
 
                 <module>spring-cloud</module>
                 <module>spring-cloud-bus</module>
@@ -1274,6 +1276,7 @@
             </build>
 
             <modules>
+                 <module>spring-boot-modules/spring-boot-cassandre</module>
                  <module>core-java-modules/core-java-9</module>
                  <module>core-java-modules/core-java-9-improvements</module>
                  <module>core-java-modules/core-java-9-jigsaw</module>

reactor-core/README.md

@@ -8,3 +8,4 @@ This module contains articles about Reactor Core.
 - [Combining Publishers in Project Reactor](https://www.baeldung.com/reactor-combine-streams)
 - [Programmatically Creating Sequences with Project Reactor](https://www.baeldung.com/flux-sequences-reactor)
 - [How to Extract a Mono’s Content in Java](https://www.baeldung.com/java-string-from-mono)
+- [How to Convert Mono<List<T\>> Into Flux<T\>](https://www.baeldung.com/java-mono-list-to-flux)

reactor-core/src/test/java/com/baeldung/mono/MonoUnitTest.java

@@ -1,10 +1,14 @@
 package com.baeldung.mono;
 
 import org.junit.Test;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
 
 import java.time.Duration;
 import java.time.temporal.ChronoUnit;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Optional;
 
 import static org.junit.Assert.assertEquals;
@@ -40,4 +44,40 @@ public class MonoUnitTest {
         // blocking
         return Mono.just("Hello world!");
     }
+
+    @Test
+    public void whenMonoProducesListOfElements_thenConvertToFluxofElements() {
+
+        Mono<List<String>> monoList = monoOfList();
+
+        StepVerifier.create(monoTofluxUsingFlatMapIterable(monoList))
+                .expectNext("one", "two", "three", "four")
+                .verifyComplete();
+
+        StepVerifier.create(monoTofluxUsingFlatMapMany(monoList))
+                .expectNext("one", "two", "three", "four")
+                .verifyComplete();
+    }
+
+    private <T> Flux<T> monoTofluxUsingFlatMapIterable(Mono<List<T>> monoList) {
+        return monoList
+                .flatMapIterable(list -> list)
+                .log();
+    }
+
+    private <T> Flux<T> monoTofluxUsingFlatMapMany(Mono<List<T>> monoList) {
+        return monoList
+                .flatMapMany(Flux::fromIterable)
+                .log();
+    }
+
+    private Mono<List<String>> monoOfList() {
+        List<String> list = new ArrayList<>();
+        list.add("one");
+        list.add("two");
+        list.add("three");
+        list.add("four");
+
+        return Mono.just(list);
+    }
 }

spring-boot-modules/spring-boot-cassandre/README.md

@@ -0,0 +1,11 @@
+# Cassandre trading bot example
+
+This project is an example of a trading bot developed with Cassandre
+
+## Running the examples
+
+* `mvn test` - Run strategy backtesting
+* `mvn spring-boot:run` - Run the bot
+
+## Relevant Articles
+- [Build a Trading Bot with Cassandre Spring Boot Starter](https://www.baeldung.com/build-a-trading-bot-with-cassandre-spring-boot-starter/)

spring-boot-modules/spring-boot-cassandre/pom.xml

@@ -0,0 +1,68 @@
+<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.4.5</version>
+		<relativePath /> <!-- lookup parent from repository -->
+	</parent>
+	<groupId>com.example</groupId>
+	<artifactId>demo</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>Cassandre trading bot tutorial</name>
+	<description>Cassandre trading bot tutorial</description>
+	<properties>
+		<java.version>11</java.version>
+	</properties>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter</artifactId>
+		</dependency>
+
+		<!-- Cassandre dependencies -->
+		<dependency>
+			<groupId>tech.cassandre.trading.bot</groupId>
+			<artifactId>cassandre-trading-bot-spring-boot-starter</artifactId>
+			<version>4.2.1</version>
+		</dependency>
+		<dependency>
+			<groupId>org.knowm.xchange</groupId>
+			<artifactId>xchange-kucoin</artifactId>
+			<version>5.0.7</version>
+		</dependency>
+		<dependency>
+			<groupId>org.hsqldb</groupId>
+			<artifactId>hsqldb</artifactId>
+			<version>2.5.1</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<!-- Cassandre dependencies -->
+		<dependency>
+			<groupId>tech.cassandre.trading.bot</groupId>
+			<artifactId>cassandre-trading-bot-spring-boot-starter-test</artifactId>
+			<version>4.2.1</version>
+			<scope>test</scope>
+		</dependency>
+
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<version>2.4.5</version>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

spring-boot-modules/spring-boot-cassandre/src/main/java/com/example/demo/DemoApplication.java

@@ -0,0 +1,13 @@
+package com.example.demo;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class DemoApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(DemoApplication.class, args);
+    }
+
+}

spring-boot-modules/spring-boot-cassandre/src/main/java/com/example/demo/MyFirstStrategy.java

@@ -0,0 +1,66 @@
+package com.example.demo;
+
+import static tech.cassandre.trading.bot.dto.position.PositionStatusDTO.CLOSED;
+import static tech.cassandre.trading.bot.dto.position.PositionStatusDTO.OPENED;
+import static tech.cassandre.trading.bot.dto.util.CurrencyDTO.BTC;
+import static tech.cassandre.trading.bot.dto.util.CurrencyDTO.USDT;
+
+import java.math.BigDecimal;
+import java.util.Optional;
+import java.util.Set;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import tech.cassandre.trading.bot.dto.market.TickerDTO;
+import tech.cassandre.trading.bot.dto.position.PositionDTO;
+import tech.cassandre.trading.bot.dto.position.PositionRulesDTO;
+import tech.cassandre.trading.bot.dto.user.AccountDTO;
+import tech.cassandre.trading.bot.dto.util.CurrencyPairDTO;
+import tech.cassandre.trading.bot.strategy.BasicCassandreStrategy;
+import tech.cassandre.trading.bot.strategy.CassandreStrategy;
+
+@CassandreStrategy
+public class MyFirstStrategy extends BasicCassandreStrategy {
+
+    private final Logger logger = LoggerFactory.getLogger(MyFirstStrategy.class);
+
+    @Override
+    public Set<CurrencyPairDTO> getRequestedCurrencyPairs() {
+        return Set.of(new CurrencyPairDTO(BTC, USDT));
+    }
+
+    @Override
+    public Optional<AccountDTO> getTradeAccount(Set<AccountDTO> accounts) {
+        return accounts.stream()
+            .filter(a -> "trade".equals(a.getName()))
+            .findFirst();
+    }
+
+    @Override
+    public void onTickerUpdate(TickerDTO ticker) {
+        logger.info("Received a new ticker : {}", ticker);
+        
+        if (new BigDecimal("56000").compareTo(ticker.getLast()) == -1) {
+
+            if (canBuy(new CurrencyPairDTO(BTC, USDT), new BigDecimal("0.01"))) {
+                PositionRulesDTO rules = PositionRulesDTO.builder()
+                    .stopGainPercentage(4f)
+                    .stopLossPercentage(25f)
+                    .build();
+                createLongPosition(new CurrencyPairDTO(BTC, USDT), new BigDecimal("0.01"), rules);
+            }
+
+        }
+    }
+
+    @Override
+    public void onPositionStatusUpdate(PositionDTO position) {
+        if (position.getStatus() == OPENED) {
+            logger.info("> New position opened : {}", position.getPositionId());
+        }
+        if (position.getStatus() == CLOSED) {
+            logger.info("> Position closed : {}", position.getDescription());
+        }
+    }
+
+}

spring-boot-modules/spring-boot-cassandre/src/main/resources/application.properties

@@ -0,0 +1,22 @@
+#
+# Exchange configuration.
+cassandre.trading.bot.exchange.name=kucoin
+cassandre.trading.bot.exchange.username=kucoin.cassandre.test@gmail.com
+cassandre.trading.bot.exchange.passphrase=cassandre
+cassandre.trading.bot.exchange.key=6054ad25365ac6000689a998
+cassandre.trading.bot.exchange.secret=af080d55-afe3-47c9-8ec1-4b479fbcc5e7
+#
+# Modes
+cassandre.trading.bot.exchange.modes.sandbox=true
+cassandre.trading.bot.exchange.modes.dry=false
+#
+# Exchange API calls rates (ms or standard ISO 8601 duration like 'PT5S').
+cassandre.trading.bot.exchange.rates.account=2000
+cassandre.trading.bot.exchange.rates.ticker=2000
+cassandre.trading.bot.exchange.rates.trade=2000
+#
+# Database configuration.
+cassandre.trading.bot.database.datasource.driver-class-name=org.hsqldb.jdbc.JDBCDriver
+cassandre.trading.bot.database.datasource.url=jdbc:hsqldb:mem:cassandre
+cassandre.trading.bot.database.datasource.username=sa
+cassandre.trading.bot.database.datasource.password=

spring-boot-modules/spring-boot-cassandre/src/test/java/com/example/demo/DemoApplicationTests.java

@@ -0,0 +1,13 @@
+package com.example.demo;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class DemoApplicationTests {
+
+    @Test
+    void contextLoads() {
+    }
+
+}

spring-boot-modules/spring-boot-cassandre/src/test/java/com/example/demo/MyFirstStrategyUnitTest.java

@@ -0,0 +1,55 @@
+package com.example.demo;
+
+import static org.awaitility.Awaitility.await;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static tech.cassandre.trading.bot.dto.position.PositionStatusDTO.OPENED;
+import static tech.cassandre.trading.bot.dto.util.CurrencyDTO.USDT;
+
+import java.util.HashMap;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Import;
+
+import tech.cassandre.trading.bot.dto.util.CurrencyDTO;
+import tech.cassandre.trading.bot.dto.util.GainDTO;
+import tech.cassandre.trading.bot.test.mock.TickerFluxMock;
+
+@SpringBootTest
+@Import(TickerFluxMock.class)
+@DisplayName("Simple strategy test")
+public class MyFirstStrategyUnitTest {
+
+    private final Logger logger = LoggerFactory.getLogger(MyFirstStrategyUnitTest.class);
+
+    @Autowired
+    private MyFirstStrategy strategy;
+
+    @Autowired
+    private TickerFluxMock tickerFluxMock;
+
+    @Test
+    @DisplayName("Check gains")
+    public void whenTickersArrives_thenCheckGains() {
+        await().forever().until(() -> tickerFluxMock.isFluxDone());
+
+        final HashMap<CurrencyDTO, GainDTO> gains = strategy.getGains();
+
+        logger.info("Cumulated gains:");
+        gains.forEach((currency, gain) -> logger.info(currency + " : " + gain.getAmount()));
+
+        logger.info("Position still opened :");
+        strategy.getPositions()
+                .values()
+                .stream()
+                .filter(p -> p.getStatus().equals(OPENED))
+                .forEach(p -> logger.info(" - {} " + p.getDescription()));
+
+        assertTrue(gains.get(USDT).getPercentage() > 0);
+    }
+    
+}

spring-boot-modules/spring-boot-cassandre/src/test/resources/application.properties

@@ -0,0 +1,22 @@
+#
+# Exchange configuration.
+cassandre.trading.bot.exchange.name=kucoin
+cassandre.trading.bot.exchange.username=kucoin.cassandre.test@gmail.com
+cassandre.trading.bot.exchange.passphrase=cassandre
+cassandre.trading.bot.exchange.key=6054ad25365ac6000689a998
+cassandre.trading.bot.exchange.secret=af080d55-afe3-47c9-8ec1-4b479fbcc5e7
+#
+# Modes
+cassandre.trading.bot.exchange.modes.sandbox=true
+cassandre.trading.bot.exchange.modes.dry=true
+#
+# Exchange API calls rates (ms or standard ISO 8601 duration like 'PT5S').
+cassandre.trading.bot.exchange.rates.account=2000
+cassandre.trading.bot.exchange.rates.ticker=2000
+cassandre.trading.bot.exchange.rates.trade=2000
+#
+# Database configuration.
+cassandre.trading.bot.database.datasource.driver-class-name=org.hsqldb.jdbc.JDBCDriver
+cassandre.trading.bot.database.datasource.url=jdbc:hsqldb:mem:cassandre
+cassandre.trading.bot.database.datasource.username=sa
+cassandre.trading.bot.database.datasource.password=

spring-boot-modules/spring-boot-cassandre/src/test/resources/tickers-btc-usdt.tsv

@@ -0,0 +1,89 @@
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spring-boot-modules/spring-boot-cassandre/src/test/resources/user-trade.tsv

@@ -0,0 +1,3 @@
+BTC	1
+USDT	100000
+ETH	10

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/FilterInterceptorApp.java

@@ -0,0 +1,11 @@
+package com.baeldung.filtersinterceptors;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication(scanBasePackages = "com.baeldung.filtersinterceptors")
+public class FilterInterceptorApp {
+    public static void main(String[] args) {
+        SpringApplication.run(FilterInterceptorApp.class, args);
+    }
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/HelloConroller.java

@@ -0,0 +1,19 @@
+package com.baeldung.filtersinterceptors;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+
+@Controller
+public class HelloConroller {
+
+    private Logger logger = LoggerFactory.getLogger(HelloConroller.class);
+
+    @GetMapping("/hello")
+    public String hello() {
+        logger.info("Hello from the controller");
+        return "hello";
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/LogFilter.java

@@ -0,0 +1,26 @@
+package com.baeldung.filtersinterceptors;
+
+import java.io.IOException;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+@Component
+public class LogFilter implements Filter {
+
+    private Logger logger = LoggerFactory.getLogger(LogFilter.class);
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+        logger.info("Hello from: " + request.getLocalAddr());
+        chain.doFilter(request, response);
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/LogInterceptor.java

@@ -0,0 +1,32 @@
+package com.baeldung.filtersinterceptors;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.HandlerInterceptor;
+import org.springframework.web.servlet.ModelAndView;
+
+public class LogInterceptor implements HandlerInterceptor {
+
+    private Logger logger = LoggerFactory.getLogger(LogInterceptor.class);
+
+    @Override
+    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
+        logger.info("preHandle");
+        return true;
+    }
+
+    @Override
+    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
+        logger.info("postHandle");
+    }
+
+    @Override
+    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
+        logger.info("afterCompletion");
+    }
+
+}