Merge branch 'master' into JAVA-5223

2021-05-17 22:37:02 +05:30
parent d9db0949cb bdd7733443
commit 8cc6444700
130 changed files with 4012 additions and 106 deletions
@@ -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>
@@ -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);
+    }
+}
+
@@ -45,4 +45,4 @@
        <providermodule.version>1.0</providermodule.version>
    </properties>

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