Merge branch 'master' into fix-5227

core-java-modules/core-java-10/pom.xml

@@ -39,7 +39,6 @@
     <properties>
         <maven.compiler.source.version>10</maven.compiler.source.version>
         <maven.compiler.target.version>10</maven.compiler.target.version>
-        <commons-collections4.version>4.1</commons-collections4.version>
     </properties>
 
 </project>

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

@@ -5,7 +5,8 @@ import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
-public class VersionUnitTest {
+// manual test as the runtime JDK version can be different depending on where the test is run
+public class VersionManualTest {
 
     @Test
     public void givenJava_whenUsingRuntime_thenGetVersion() {

core-java-modules/core-java-8/pom.xml

@@ -43,9 +43,4 @@
         </resources>
     </build>
 
-    <properties>
-        <!-- util -->
-        <commons-collections4.version>4.1</commons-collections4.version>
-    </properties>
-
 </project>

core-java-modules/core-java-9-jigsaw/src/test/java/com/baeldung/java9/modules/ModuleAPIUnitTest.java

@@ -16,6 +16,7 @@ import java.util.stream.Collectors;
 
 import org.junit.Before;
 import org.junit.Test;
+import org.junit.Ignore;
 
 public class ModuleAPIUnitTest {
 
@@ -110,6 +111,7 @@ public class ModuleAPIUnitTest {
     }
 
     @Test
+    @Ignore // fixing in http://team.baeldung.com/browse/JAVA-8679
     public void givenModules_whenAccessingModuleDescriptorProvides_thenProvidesAreReturned() {
         Set<Provides> javaBaseProvides = javaBaseModule.getDescriptor().provides();
         Set<Provides> javaSqlProvides = javaSqlModule.getDescriptor().provides();

core-java-modules/core-java-9/pom.xml

@@ -76,7 +76,6 @@
         <maven.compiler.source>1.9</maven.compiler.source>
         <maven.compiler.target>1.9</maven.compiler.target>
         <guava.version>25.1-jre</guava.version>
-        <commons-collections4.version>4.1</commons-collections4.version>
     </properties>
 
 </project>

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

@@ -44,7 +44,6 @@
 
     <properties>
         <eclipse.collections.version>7.1.0</eclipse.collections.version>
-        <commons-collections4.version>4.1</commons-collections4.version>
         <commons-exec.version>1.3</commons-exec.version>
     </properties>
 

core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/DynamicTypeValue.java

@@ -0,0 +1,5 @@
+package com.baeldung.collections.mulipletypesinmap;
+
+public interface DynamicTypeValue {
+    String valueDescription();
+}

core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/InstantTypeValue.java

@@ -0,0 +1,24 @@
+package com.baeldung.collections.mulipletypesinmap;
+
+import java.time.Instant;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+
+public class InstantTypeValue implements DynamicTypeValue {
+    private static DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
+        .withZone(ZoneId.systemDefault());
+    private Instant value;
+
+    public InstantTypeValue(Instant value) {
+        this.value = value;
+    }
+
+    @Override
+    public String valueDescription() {
+        if (value == null) {
+            return "The value is null.";
+        }
+        return String.format("The value is an instant: %s", FORMATTER.format(value));
+    }
+
+}

core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/IntArrayTypeValue.java

@@ -0,0 +1,20 @@
+package com.baeldung.collections.mulipletypesinmap;
+
+import java.util.Arrays;
+
+public class IntArrayTypeValue implements DynamicTypeValue {
+    private int[] value;
+
+    public IntArrayTypeValue(int[] value) {
+        this.value = value;
+    }
+
+    @Override
+    public String valueDescription() {
+        if (value == null) {
+            return "The value is null.";
+        }
+        return String.format("The value is an array of %d integers: %s", value.length, Arrays.toString(value));
+    }
+
+}

core-java-modules/core-java-collections-4/src/main/java/com/baeldung/collections/mulipletypesinmap/IntegerTypeValue.java

@@ -0,0 +1,17 @@
+package com.baeldung.collections.mulipletypesinmap;
+
+public class IntegerTypeValue implements DynamicTypeValue {
+    private Integer value;
+
+    public IntegerTypeValue(Integer value) {
+        this.value = value;
+    }
+
+    @Override
+    public String valueDescription() {
+        if(value == null){
+            return "The value is null.";
+        }
+        return String.format("The value is a %s integer: %d", value > 0 ? "positive" : "negative", value);
+    }
+}

core-java-modules/core-java-collections-4/src/test/java/com/baeldung/multipletypesinmap/MultipleTypesInMapUnitTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.multipletypesinmap;
+
+import com.baeldung.collections.mulipletypesinmap.DynamicTypeValue;
+import com.baeldung.collections.mulipletypesinmap.InstantTypeValue;
+import com.baeldung.collections.mulipletypesinmap.IntArrayTypeValue;
+import com.baeldung.collections.mulipletypesinmap.IntegerTypeValue;
+import org.junit.jupiter.api.Test;
+
+import java.time.Instant;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class MultipleTypesInMapUnitTest {
+    private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
+        .withZone(ZoneId.systemDefault());
+
+    private static final Integer intValue = 777;
+    private static final int[] intArray = new int[]{2, 3, 5, 7, 11, 13};
+    private static final Instant instant = Instant.now();
+
+    private static final String KEY_INT = "E1 (Integer)";
+    private static final String KEY_INT_ARRAY = "E2 (IntArray)";
+    private static final String KEY_INSTANT = "E3 (Instant)";
+
+    @Test
+    void givenThreeTypes_whenUsingRawMap_thenPrintDescription() {
+        Map<String, Object> rawMap = new HashMap<>();
+        rawMap.put(KEY_INT, intValue);
+        rawMap.put(KEY_INT_ARRAY, intArray);
+        rawMap.put(KEY_INSTANT, instant);
+
+        rawMap.forEach((k, v) -> {
+            if (v instanceof Integer) {
+                Integer theV = (Integer) v;
+                String desc = String.format("The value is a %s integer: %d", theV > 0 ? "positive" : "negative", theV);
+                System.out.println(k + " -> " + desc);
+                assertThat(k).isEqualTo(KEY_INT);
+                assertThat(desc).isEqualTo("The value is a positive integer: 777");
+            } else if (v instanceof int[]) {
+                int[] theV = (int[]) v;
+                String desc = String.format("The value is an array of %d integers: %s", theV.length, Arrays.toString(theV));
+                System.out.println(k + " -> " + desc);
+                assertThat(k).isEqualTo(KEY_INT_ARRAY);
+                assertThat(desc).isEqualTo("The value is an array of 6 integers: [2, 3, 5, 7, 11, 13]");
+            } else if (v instanceof Instant) {
+                Instant theV = (Instant) v;
+                String desc = String.format("The value is an instant: %s", FORMATTER.format(theV));
+                System.out.println(k + " -> " + desc);
+                assertThat(k).isEqualTo(KEY_INSTANT);
+                assertThat(desc).matches("^The value is an instant: \\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}");
+            } else {
+                throw new IllegalStateException("Unknown Type found.");
+            }
+        });
+    }
+
+    @Test
+    void givenThreeTypes_whenUsingAnInterface_thenPrintDescription() {
+        Map<String, DynamicTypeValue> theMap = new HashMap<>();
+        theMap.put(KEY_INT, new IntegerTypeValue(intValue));
+        theMap.put(KEY_INT_ARRAY, new IntArrayTypeValue(intArray));
+        theMap.put(KEY_INSTANT, new InstantTypeValue(instant));
+
+        theMap.forEach((k, v) -> System.out.println(k + " -> " + v.valueDescription()));
+
+        assertThat(theMap.get(KEY_INT).valueDescription()).isEqualTo("The value is a positive integer: 777");
+        assertThat(theMap.get(KEY_INT_ARRAY).valueDescription()).isEqualTo("The value is an array of 6 integers: [2, 3, 5, 7, 11, 13]");
+        assertThat(theMap.get(KEY_INSTANT).valueDescription()).matches("^The value is an instant: \\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}");
+    }
+}

core-java-modules/core-java-collections-array-list/pom.xml

@@ -22,8 +22,4 @@
         </dependency>
     </dependencies>
 
-    <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
-    </properties>
-
 </project>

core-java-modules/core-java-collections-list-2/pom.xml

@@ -28,8 +28,4 @@
         </dependency>
     </dependencies>
 
-    <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
-    </properties>
-
 </project>

core-java-modules/core-java-collections-list-3/pom.xml

@@ -54,7 +54,6 @@
     </dependencies>
 
     <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
         <trove4j.version>3.0.2</trove4j.version>
         <fastutil.version>8.1.0</fastutil.version>
         <colt.version>1.2.0</colt.version>

core-java-modules/core-java-collections-list/pom.xml

@@ -27,8 +27,4 @@
         </dependency>
     </dependencies>
 
-    <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
-    </properties>
-
 </project>

core-java-modules/core-java-collections-maps-2/pom.xml

@@ -55,7 +55,6 @@
 
     <properties>
         <streamex.version>0.6.5</streamex.version>
-        <commons-collections4.version>4.1</commons-collections4.version>
         <avaitility.version>1.7.0</avaitility.version>
         <eclipse-collections.version>8.2.0</eclipse-collections.version>
         <hppc.version>0.7.2</hppc.version>

core-java-modules/core-java-collections-maps-4/pom.xml

@@ -28,12 +28,6 @@
 			<version>${junit.version}</version>
 			<scope>test</scope>
 		</dependency>
-		<dependency>
-			<groupId>org.hamcrest</groupId>
-			<artifactId>hamcrest-all</artifactId>
-			<version>${hamcrest-all.version}</version>
-			<scope>test</scope>
-		</dependency>
 	</dependencies>
 
 	<build>

core-java-modules/core-java-collections-maps/pom.xml

@@ -22,8 +22,4 @@
         </dependency>
     </dependencies>
 
-    <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
-    </properties>
-
 </project>

core-java-modules/core-java-collections-set/pom.xml

@@ -49,7 +49,6 @@
     <properties>
         <maven.compiler.source>11</maven.compiler.source>
         <maven.compiler.target>11</maven.compiler.target>
-        <commons-collections4.version>4.3</commons-collections4.version>
         <gson.version>2.8.5</gson.version>
     </properties>
 

core-java-modules/core-java-concurrency-advanced/pom.xml

@@ -56,7 +56,6 @@
     <properties>
         <guava.version>21.0</guava.version>
         <commons-math3.version>3.6.1</commons-math3.version>
-        <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>
         <avaitility.version>1.7.0</avaitility.version>
     </properties>

core-java-modules/core-java-exceptions-3/src/test/java/com/baeldung/exceptions/illegalmonitorstate/IllegalMonitorStateExceptionUnitTest.java

@@ -1,11 +1,12 @@
 package com.baeldung.exceptions.illegalmonitorstate;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 import org.junit.jupiter.api.Test;
 
-import java.time.Duration;
-
-import static org.junit.jupiter.api.Assertions.*;
-
 public class IllegalMonitorStateExceptionUnitTest {
 
     @Test
@@ -20,11 +21,11 @@ public class IllegalMonitorStateExceptionUnitTest {
         Thread senderThread = new Thread(sender, "sender-thread");
         senderThread.start();
 
-        senderThread.join(1000);
-        receiverThread.join(1000);
+        // we need to wait for the sender and receiver threads to finish
+        senderThread.join(10_000);
+        receiverThread.join(10_000);
 
-        // we need to wait for enough time so that sender has had a chance to send the data
-        assertTimeout(Duration.ofSeconds(10), () -> assertEquals("test", receiver.getMessage()));
+        assertEquals("test", receiver.getMessage());
         assertFalse(sender.hasIllegalMonitorStateExceptionOccurred());
         assertFalse(receiver.hasIllegalMonitorStateExceptionOccurred());
     }

core-java-modules/core-java-io-conversions/src/test/java/com/baeldung/readertox/JavaReaderToXUnitTest.java

@@ -1,7 +1,7 @@
 package com.baeldung.readertox;
 
 import static org.hamcrest.CoreMatchers.equalTo;
-import static org.junit.Assert.assertThat;
+import static org.hamcrest.MatcherAssert.assertThat;
 
 import java.io.ByteArrayInputStream;
 import java.io.File;
@@ -17,6 +17,7 @@ import java.nio.charset.StandardCharsets;
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.io.input.CharSequenceReader;
+import org.apache.commons.io.input.ReaderInputStream;
 import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -181,7 +182,7 @@ public class JavaReaderToXUnitTest {
     }
 
     @Test
-    public void givenUsingCommonsIO_whenConvertingReaderIntoInputStream() throws IOException {
+    public void givenUsingCommonsIOUtils_whenConvertingReaderIntoInputStream() throws IOException {
         final Reader initialReader = new StringReader("With Commons IO");
 
         final InputStream targetStream = IOUtils.toInputStream(IOUtils.toString(initialReader));
@@ -191,7 +192,7 @@ public class JavaReaderToXUnitTest {
     }
 
     @Test
-    public void givenUsingCommonsIO_whenConvertingReaderIntoInputStream_thenCorrect() throws IOException {
+    public void givenUsingCommonsIOUtils_whenConvertingReaderIntoInputStream_thenCorrect() throws IOException {
         String initialString = "With Commons IO";
         final Reader initialReader = new StringReader(initialString);
 
@@ -204,6 +205,30 @@ public class JavaReaderToXUnitTest {
         targetStream.close();
     }
 
+    @Test
+    public void givenUsingCommonsIOReaderInputStream_whenConvertingReaderIntoInputStream() throws IOException {
+        final Reader initialReader = new StringReader("With Commons IO");
+
+        final InputStream targetStream = new ReaderInputStream(initialReader);
+
+        initialReader.close();
+        targetStream.close();
+    }
+
+    @Test
+    public void givenUsingCommonsIOReaderInputStream_whenConvertingReaderIntoInputStream_thenCorrect() throws IOException {
+        String initialString = "With Commons IO";
+        final Reader initialReader = new StringReader(initialString);
+
+        final InputStream targetStream = new ReaderInputStream(initialReader);
+
+        final String finalString = IOUtils.toString(targetStream);
+        assertThat(finalString, equalTo(initialString));
+
+        initialReader.close();
+        targetStream.close();
+    }
+
     // tests - Reader to InputStream with encoding
 
     @Test
@@ -233,7 +258,7 @@ public class JavaReaderToXUnitTest {
     }
 
     @Test
-    public void givenUsingCommonsIO_whenConvertingReaderIntoInputStreamWithEncoding() throws IOException {
+    public void givenUsingCommonsIOUtils_whenConvertingReaderIntoInputStreamWithEncoding() throws IOException {
         final Reader initialReader = new StringReader("With Commons IO");
 
         final InputStream targetStream = IOUtils.toInputStream(IOUtils.toString(initialReader), Charsets.UTF_8);
@@ -243,7 +268,7 @@ public class JavaReaderToXUnitTest {
     }
 
     @Test
-    public void givenUsingCommonsIO_whenConvertingReaderIntoInputStreamWithEncoding_thenCorrect() throws IOException {
+    public void givenUsingCommonsIOUtils_whenConvertingReaderIntoInputStreamWithEncoding_thenCorrect() throws IOException {
         String initialString = "With Commons IO";
         final Reader initialReader = new StringReader(initialString);
         final InputStream targetStream = IOUtils.toInputStream(IOUtils.toString(initialReader), Charsets.UTF_8);
@@ -255,4 +280,27 @@ public class JavaReaderToXUnitTest {
         targetStream.close();
     }
 
+    @Test
+    public void givenUsingCommonsIOReaderInputStream_whenConvertingReaderIntoInputStreamWithEncoding() throws IOException {
+        final Reader initialReader = new StringReader("With Commons IO");
+
+        final InputStream targetStream = new ReaderInputStream(initialReader, Charsets.UTF_8);
+
+        initialReader.close();
+        targetStream.close();
+    }
+
+    @Test
+    public void givenUsingCommonsIOReaderInputStream_whenConvertingReaderIntoInputStreamWithEncoding_thenCorrect() throws IOException {
+        String initialString = "With Commons IO";
+        final Reader initialReader = new StringReader(initialString);
+
+        final InputStream targetStream = new ReaderInputStream(initialReader, Charsets.UTF_8);
+
+        String finalString = IOUtils.toString(targetStream, Charsets.UTF_8);
+        assertThat(finalString, equalTo(initialString));
+
+        initialReader.close();
+        targetStream.close();
+    }
 }

core-java-modules/core-java-lang-oop-modifiers/pom.xml

@@ -22,4 +22,7 @@
         </dependency>
     </dependencies>
 
+    <properties>
+        <h2.version>1.4.197</h2.version> <!-- needs to be specified as it fails with parent's 1.4.200 -->
+    </properties>
 </project>

core-java-modules/core-java-networking-3/README.md

@@ -9,4 +9,5 @@ This module contains articles about networking in Java
 - [Connection Timeout vs. Read Timeout for Java Sockets](https://www.baeldung.com/java-socket-connection-read-timeout)
 - [Find Whether an IP Address Is in the Specified Range or Not in Java](https://www.baeldung.com/java-check-ip-address-range)
 - [Find the IP Address of a Client Connected to a Server](https://www.baeldung.com/java-client-get-ip-address)
+- [Unix Domain Socket in Java 16](https://www.baeldung.com/java-unix-domain-socket)
 - [[<-- Prev]](/core-java-modules/core-java-networking-2)

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

@@ -64,6 +64,16 @@
                 </plugin>
             </plugins>
         </pluginManagement>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>16</source>
+                    <target>16</target>
+                </configuration>
+            </plugin>
+        </plugins>
     </build>
 
     <properties>

core-java-modules/core-java-networking-3/src/main/java/com/baeldung/socket/UnixDomainSocketClient.java

@@ -0,0 +1,49 @@
+package com.baeldung.socket;
+
+import java.io.IOException;
+import java.net.StandardProtocolFamily;
+import java.net.UnixDomainSocketAddress;
+import java.nio.ByteBuffer;
+import java.nio.channels.SocketChannel;
+import java.nio.file.Path;
+
+class UnixDomainSocketClient {
+
+    public static void main(String[] args) throws Exception {
+        new UnixDomainSocketClient().runClient();
+    }
+
+    void runClient() throws IOException {
+        Path socketPath = Path.of(System.getProperty("user.home"))
+          .resolve("baeldung.socket");
+        UnixDomainSocketAddress socketAddress = getAddress(socketPath);
+
+        SocketChannel channel = openSocketChannel(socketAddress);
+
+        String message = "Hello from Baeldung Unix domain socket article";
+        writeMessage(channel, message);
+    }
+
+    UnixDomainSocketAddress getAddress(Path socketPath) {
+        return UnixDomainSocketAddress.of(socketPath);
+    }
+
+    SocketChannel openSocketChannel(UnixDomainSocketAddress socketAddress) throws IOException {
+        SocketChannel channel = SocketChannel
+          .open(StandardProtocolFamily.UNIX);
+        channel.connect(socketAddress);
+        return channel;
+    }
+
+    void writeMessage(SocketChannel socketChannel, String message) throws IOException {
+        ByteBuffer buffer = ByteBuffer.allocate(1024);
+        buffer.clear();
+        buffer.put(message.getBytes());
+        buffer.flip();
+
+        while (buffer.hasRemaining()) {
+            socketChannel.write(buffer);
+        }
+    }
+
+}

core-java-modules/core-java-networking-3/src/main/java/com/baeldung/socket/UnixDomainSocketServer.java

@@ -0,0 +1,57 @@
+package com.baeldung.socket;
+
+import java.io.IOException;
+import java.net.StandardProtocolFamily;
+import java.net.UnixDomainSocketAddress;
+import java.nio.ByteBuffer;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Optional;
+
+class UnixDomainSocketServer {
+
+    public static void main(String[] args) throws IOException, InterruptedException {
+        new UnixDomainSocketServer().runServer();
+    }
+
+    void runServer() throws IOException, InterruptedException {
+        Path socketPath = Path.of(System.getProperty("user.home"))
+          .resolve("baeldung.socket");
+        Files.deleteIfExists(socketPath);
+        UnixDomainSocketAddress socketAddress = getAddress(socketPath);
+
+        ServerSocketChannel serverChannel = createServerSocketChannel(socketAddress);
+
+        SocketChannel channel = serverChannel.accept();
+
+        while (true) {
+            readSocketMessage(channel)
+              .ifPresent(message -> System.out.printf("[Client message] %s%n", message));
+            Thread.sleep(100);
+        }
+    }
+
+    UnixDomainSocketAddress getAddress(Path socketPath) {
+        return UnixDomainSocketAddress.of(socketPath);
+    }
+
+    ServerSocketChannel createServerSocketChannel(UnixDomainSocketAddress socketAddress) throws IOException {
+        ServerSocketChannel serverChannel = ServerSocketChannel.open(StandardProtocolFamily.UNIX);
+        serverChannel.bind(socketAddress);
+        return serverChannel;
+    }
+
+    Optional<String> readSocketMessage(SocketChannel channel) throws IOException {
+        ByteBuffer buffer = ByteBuffer.allocate(1024);
+        int bytesRead = channel.read(buffer);
+        if (bytesRead < 0) return Optional.empty();
+        byte[] bytes = new byte[bytesRead];
+        buffer.flip();
+        buffer.get(bytes);
+        String message = new String(bytes);
+        return Optional.of(message);
+    }
+
+}

core-java-modules/core-java-networking-3/src/test/java/com/baeldung/socket/FindFreePortManualTest.java

@@ -14,7 +14,8 @@ import java.net.ServerSocket;
 import static org.assertj.core.api.Assertions.*;
 import static org.assertj.core.api.Assertions.assertThat;
 
-public class FindFreePortUnitTest {
+// fixing in JAVA-8748
+public class FindFreePortManualTest {
 
     private static int FREE_PORT_NUMBER;
     private static int[] FREE_PORT_RANGE;

core-java-modules/core-java-networking-3/src/test/java/com/baeldung/socket/UnixDomainSocketClientUnitTest.java

@@ -0,0 +1,82 @@
+package com.baeldung.socket;
+
+import org.junit.Test;
+import org.mockito.Mockito;
+import org.mockito.stubbing.Answer;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.StandardProtocolFamily;
+import java.net.UnixDomainSocketAddress;
+import java.nio.ByteBuffer;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+import java.nio.file.Path;
+import java.util.UUID;
+
+import static java.nio.file.Files.deleteIfExists;
+import static org.assertj.core.util.Files.newTemporaryFile;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class UnixDomainSocketClientUnitTest {
+
+    @Test
+    public void givenSocketPath_shouldCreateUnixDomainSocketAddress() {
+        // given
+        File tempFile = newTemporaryFile();
+        Path socketPath = tempFile.toPath();
+
+        // when
+        UnixDomainSocketAddress address = new UnixDomainSocketClient().getAddress(socketPath);
+
+        // then
+        assertEquals(address.getPath(), socketPath);
+
+        // cleanup
+        tempFile.delete();
+    }
+
+    @Test
+    public void givenUnixDomainSocketAddress_shouldOpenSocketChannel() throws IOException {
+        // given
+        File tempFile = newTemporaryFile();
+        Path socketPath = tempFile.toPath();
+        deleteIfExists(socketPath);
+        UnixDomainSocketAddress address = UnixDomainSocketAddress.of(socketPath);
+
+        // bind address as a unix domain socket
+        ServerSocketChannel serverChannel = ServerSocketChannel.open(StandardProtocolFamily.UNIX);
+        serverChannel.bind(address);
+
+        // when
+        SocketChannel socketChannel = new UnixDomainSocketClient().openSocketChannel(address);
+
+        // then
+        assertTrue(socketChannel.isOpen());
+        assertEquals(socketChannel.getRemoteAddress(), address);
+
+        // cleanup
+        tempFile.delete();
+    }
+
+    @Test
+    public void givenSocketChannelAndMessage_shouldWriteMessage() throws IOException {
+        // given
+        SocketChannel socketChannel = Mockito.mock(SocketChannel.class);
+        String message = UUID.randomUUID().toString();
+        Mockito.when(socketChannel.write(Mockito.any(ByteBuffer.class)))
+          .thenAnswer(
+            (Answer<Integer>) invocationOnMock -> {
+              ((ByteBuffer) invocationOnMock.getArguments()[0]).position(message.getBytes().length);
+              return -1;
+            }
+          );
+
+        // when
+        new UnixDomainSocketClient().writeMessage(socketChannel, message);
+
+        // then
+        Mockito.verify(socketChannel, Mockito.times(1)).write(Mockito.any(ByteBuffer.class));
+    }
+}

core-java-modules/core-java-networking-3/src/test/java/com/baeldung/socket/UnixDomainSocketServerUnitTest.java

@@ -0,0 +1,50 @@
+package com.baeldung.socket;
+
+import org.junit.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.UnixDomainSocketAddress;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.file.Path;
+
+import static java.nio.file.Files.deleteIfExists;
+import static org.assertj.core.util.Files.newTemporaryFile;
+import static org.junit.Assert.assertEquals;
+
+public class UnixDomainSocketServerUnitTest {
+
+    @Test
+    public void givenSocketPath_shouldCreateUnixDomainSocketAddress() {
+        // given
+        File tempFile = newTemporaryFile();
+        Path socketPath = tempFile.toPath();
+
+        // when
+        UnixDomainSocketAddress address = new UnixDomainSocketServer().getAddress(socketPath);
+
+        // then
+        assertEquals(address.getPath(), socketPath);
+
+        // cleanup
+        tempFile.delete();
+    }
+
+    @Test
+    public void givenUnixDomainSocketAddress_shouldCreateServerSocketChannel() throws IOException {
+        // given
+        File tempFile = newTemporaryFile();
+        Path socketPath = tempFile.toPath();
+        deleteIfExists(socketPath);
+        UnixDomainSocketAddress address = UnixDomainSocketAddress.of(socketPath);
+
+        // when
+        ServerSocketChannel serverSocketChannel = new UnixDomainSocketServer().createServerSocketChannel(address);
+
+        // then
+        assertEquals(serverSocketChannel.getLocalAddress(), address);
+
+        // cleanup
+        tempFile.delete();
+    }
+}