Merge branch 'master' into JAVA-7244-Review_log_statements_for_projects

2021-12-09 10:22:41 +02:00
parent e3aebd9c10 1b2115b2ce
commit 4054e8f860
1079 changed files with 12491 additions and 4924 deletions
@@ -12,7 +12,6 @@
        <groupId>com.baeldung.core-java-modules</groupId>
        <artifactId>core-java-modules</artifactId>
        <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../</relativePath>
    </parent>

    <dependencies>
@@ -40,7 +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>
@@ -12,7 +12,7 @@
        <groupId>com.baeldung</groupId>
        <artifactId>parent-modules</artifactId>
        <version>1.0.0-SNAPSHOT</version>
-        <relativePath>../..</relativePath>
+        <relativePath>../../pom.xml</relativePath>
    </parent>

    <dependencies>
@@ -21,35 +21,11 @@
            <artifactId>guava</artifactId>
            <version>${guava.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.mock-server</groupId>
            <artifactId>mockserver-junit-jupiter</artifactId>
            <version>${mockserver.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-engine</artifactId>
-            <version>${junit-jupiter.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-params</artifactId>
-            <version>${junit-jupiter.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-api</artifactId>
-            <version>${junit-jupiter.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
@@ -60,18 +36,6 @@
            <artifactId>jakarta.xml.ws-api</artifactId>
            <version>${jakarta.ws-api.version}</version>
        </dependency>
-        <dependency>
-            <groupId>com.sun.xml.ws</groupId>
-            <artifactId>jaxws-rt</artifactId>
-            <version>${jaxws-rt.version}</version>
-            <scope>runtime</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.sun.xml.ws</groupId>
-            <artifactId>jaxws-ri</artifactId>
-            <version>${jaxws-ri.version}</version>
-            <type>pom</type>
-        </dependency>
    </dependencies>

    <build>
@@ -106,13 +70,9 @@
        <maven.compiler.source.version>11</maven.compiler.source.version>
        <maven.compiler.target.version>11</maven.compiler.target.version>
        <guava.version>29.0-jre</guava.version>
-        <assertj.version>3.17.2</assertj.version>
        <mockserver.version>5.11.1</mockserver.version>
-        <commons-lang3.version>3.12.0</commons-lang3.version>
-        <jakarta.ws-api.version>3.0.0</jakarta.ws-api.version>
-        <jaxws-rt.version>3.0.0</jaxws-rt.version>
-        <jaxws-ri.version>2.3.1</jaxws-ri.version>
-        <jaxws-maven-plugin.version>2.3.2</jaxws-maven-plugin.version>
+        <jakarta.ws-api.version>3.0.1</jakarta.ws-api.version>
+        <jaxws-maven-plugin.version>3.0.2</jaxws-maven-plugin.version>
    </properties>

 </project>
@@ -0,0 +1,41 @@
+package com.baeldung.httpsclientauthentication;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import javax.net.SocketFactory;
+import javax.net.ssl.SSLSocket;
+import javax.net.ssl.SSLSocketFactory;
+
+public class SSLScocketClient {
+
+    static void startClient(String host, int port) throws IOException {
+
+        SocketFactory factory = SSLSocketFactory.getDefault();
+
+        try (SSLSocket socket = (SSLSocket) factory.createSocket(host, port)) {
+            socket.setEnabledCipherSuites(new String[] { "TLS_AES_128_GCM_SHA256" });
+            socket.setEnabledProtocols(new String[] { "TLSv1.3" });
+            InputStream is = new BufferedInputStream(socket.getInputStream());
+            String message = "Hello World Message";
+            System.out.println("sending message: " + message);
+            OutputStream os = new BufferedOutputStream(socket.getOutputStream());
+            os.write(message.getBytes());
+            os.flush();
+            byte[] data = new byte[2048];
+            int len = is.read(data);
+            if (len <= 0) {
+                throw new IOException("no data received");
+            }
+            System.out.printf("client received %d bytes: %s%n", len, new String(data, 0, len));
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+
+        startClient("localhost", 8443);
+    }
+}
@@ -0,0 +1,46 @@
+package com.baeldung.httpsclientauthentication;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.Socket;
+
+import javax.net.ServerSocketFactory;
+import javax.net.ssl.SSLServerSocket;
+import javax.net.ssl.SSLServerSocketFactory;
+
+public class SSLSocketEchoServer {
+
+    static void startServer(int port) throws IOException {
+
+        ServerSocketFactory factory = SSLServerSocketFactory.getDefault();
+
+        try (SSLServerSocket listener = (SSLServerSocket) factory.createServerSocket(port)) {
+            listener.setNeedClientAuth(true);
+            listener.setEnabledCipherSuites(new String[] { "TLS_AES_128_GCM_SHA256" });
+            listener.setEnabledProtocols(new String[] { "TLSv1.3" });
+            System.out.println("listening for messages...");
+            try (Socket socket = listener.accept()) {
+                InputStream is = new BufferedInputStream(socket.getInputStream());
+                OutputStream os = new BufferedOutputStream(socket.getOutputStream());
+                byte[] data = new byte[2048];
+                int len = is.read(data);
+                if (len <= 0) {
+                    throw new IOException("no data received");
+                }
+                String message = new String(data, 0, len);
+                System.out.printf("server received %d bytes: %s%n", len, message);
+                String response = message + " processed by server";
+                os.write(response.getBytes(), 0, response.getBytes().length);
+                os.flush();
+            }
+            System.out.println("message processed, exiting");
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        startServer(8443);
+    }
+}
@@ -1,10 +1,10 @@

 package com.baeldung.soap.ws.client.generated;

-import javax.xml.bind.annotation.XmlAccessType;
-import javax.xml.bind.annotation.XmlAccessorType;
-import javax.xml.bind.annotation.XmlSchemaType;
-import javax.xml.bind.annotation.XmlType;
+import jakarta.xml.bind.annotation.XmlAccessType;
+import jakarta.xml.bind.annotation.XmlAccessorType;
+import jakarta.xml.bind.annotation.XmlSchemaType;
+import jakarta.xml.bind.annotation.XmlType;


 /**
@@ -1,19 +1,19 @@

 package com.baeldung.soap.ws.client.generated;

-import javax.jws.WebMethod;
-import javax.jws.WebParam;
-import javax.jws.WebResult;
-import javax.jws.WebService;
-import javax.jws.soap.SOAPBinding;
-import javax.xml.bind.annotation.XmlSeeAlso;
-import javax.xml.ws.Action;
+import jakarta.jws.WebMethod;
+import jakarta.jws.WebParam;
+import jakarta.jws.WebResult;
+import jakarta.jws.WebService;
+import jakarta.jws.soap.SOAPBinding;
+import jakarta.xml.bind.annotation.XmlSeeAlso;
+import jakarta.xml.ws.Action;


 /**
 * This class was generated by the JAX-WS RI.
- * JAX-WS RI 2.3.2
- * Generated source version: 2.2
+ * JAX-WS RI 3.0.2
+ * Generated source version: 3.0
 * 
 */
@WebService(name = "CountryService", targetNamespace = "http://server.ws.soap.baeldung.com/")
@@ -4,17 +4,17 @@ package com.baeldung.soap.ws.client.generated;
 import java.net.MalformedURLException;
 import java.net.URL;
 import javax.xml.namespace.QName;
-import javax.xml.ws.Service;
-import javax.xml.ws.WebEndpoint;
-import javax.xml.ws.WebServiceClient;
-import javax.xml.ws.WebServiceException;
-import javax.xml.ws.WebServiceFeature;
+import jakarta.xml.ws.Service;
+import jakarta.xml.ws.WebEndpoint;
+import jakarta.xml.ws.WebServiceClient;
+import jakarta.xml.ws.WebServiceException;
+import jakarta.xml.ws.WebServiceFeature;


 /**
 * This class was generated by the JAX-WS RI.
- * JAX-WS RI 2.3.2
- * Generated source version: 2.2
+ * JAX-WS RI 3.0.2
+ * Generated source version: 3.0
 * 
 */
@WebServiceClient(name = "CountryServiceImplService", targetNamespace = "http://server.ws.soap.baeldung.com/", wsdlLocation = "http://localhost:8888/ws/country?wsdl")
@@ -75,7 +75,7 @@ public class CountryServiceImplService
    /**
     * 
     * @param features
-     *     A list of {@link javax.xml.ws.WebServiceFeature} to configure on the proxy.  Supported features not in the <code>features</code> parameter will have their default values.
+     *     A list of {@link jakarta.xml.ws.WebServiceFeature} to configure on the proxy.  Supported features not in the <code>features</code> parameter will have their default values.
     * @return
     *     returns CountryService
     */
@@ -1,15 +1,14 @@

 package com.baeldung.soap.ws.client.generated;

-import javax.xml.bind.annotation.XmlEnum;
-import javax.xml.bind.annotation.XmlType;
+import jakarta.xml.bind.annotation.XmlEnum;
+import jakarta.xml.bind.annotation.XmlType;


 /**
 * <p>Java class for currency.
 * 
 * <p>The following schema fragment specifies the expected content contained within this class.
- * <p>
 * <pre>
 * &lt;simpleType name="currency"&gt;
 *   &lt;restriction base="{http://www.w3.org/2001/XMLSchema}string"&gt;
@@ -1,7 +1,7 @@

 package com.baeldung.soap.ws.client.generated;

-import javax.xml.bind.annotation.XmlRegistry;
+import jakarta.xml.bind.annotation.XmlRegistry;


 /**
@@ -1,2 +1,2 @@
-@javax.xml.bind.annotation.XmlSchema(namespace = "http://server.ws.soap.baeldung.com/")
+@jakarta.xml.bind.annotation.XmlSchema(namespace = "http://server.ws.soap.baeldung.com/")
 package com.baeldung.soap.ws.client.generated;
@@ -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() {
@@ -13,7 +13,8 @@
        <groupId>com.baeldung</groupId>
        <artifactId>parent-modules</artifactId>
        <version>1.0.0-SNAPSHOT</version>
-        <relativePath>../..</relativePath>
+
+        <relativePath>../../pom.xml</relativePath>
    </parent>

    <dependencies>
@@ -22,12 +23,6 @@
            <artifactId>guava</artifactId>
            <version>${guava.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.openjdk.jmh</groupId>
            <artifactId>jmh-core</artifactId>
@@ -104,7 +99,6 @@
        <maven.compiler.source.version>11</maven.compiler.source.version>
        <maven.compiler.target.version>11</maven.compiler.target.version>
        <guava.version>27.1-jre</guava.version>
-        <assertj.version>3.11.1</assertj.version>
        <uberjar.name>benchmarks</uberjar.name>
        <eclipse.collections.version>10.0.0</eclipse.collections.version>
        <shade.plugin.version>3.2.4</shade.plugin.version>
@@ -13,20 +13,13 @@
        <groupId>com.baeldung</groupId>
        <artifactId>parent-modules</artifactId>
        <version>1.0.0-SNAPSHOT</version>
-        <relativePath>../../</relativePath>
    </parent>

    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
-            <version>2.11.0</version>
+            <version>${commons-io.version}</version>
        </dependency>
    </dependencies>

@@ -54,7 +47,6 @@
    <properties>
        <maven.compiler.source.version>12</maven.compiler.source.version>
        <maven.compiler.target.version>12</maven.compiler.target.version>
-        <assertj.version>3.6.1</assertj.version>
    </properties>

 </project>
@@ -14,18 +14,8 @@
        <groupId>com.baeldung</groupId>
        <artifactId>parent-modules</artifactId>
        <version>1.0.0-SNAPSHOT</version>
-        <relativePath>../../</relativePath>
    </parent>

-    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
    <build>
        <plugins>
            <plugin>
@@ -53,7 +43,6 @@
    <properties>
        <maven.compiler.source.version>13</maven.compiler.source.version>
        <maven.compiler.target.version>13</maven.compiler.target.version>
-        <assertj.version>3.6.1</assertj.version>
        <surefire.plugin.version>3.0.0-M3</surefire.plugin.version>
    </properties>

@@ -12,30 +12,8 @@
        <groupId>com.baeldung</groupId>
        <artifactId>parent-modules</artifactId>
        <version>1.0.0-SNAPSHOT</version>
-        <relativePath>../../</relativePath>
    </parent>

-    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-engine</artifactId>
-            <version>${junit-jupiter.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-api</artifactId>
-            <version>${junit-jupiter.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
    <build>
        <plugins>
            <plugin>
@@ -62,7 +40,6 @@

    <properties>
        <maven.compiler.release>14</maven.compiler.release>
-        <assertj.version>3.6.1</assertj.version>
        <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
        <surefire.plugin.version>3.0.0-M3</surefire.plugin.version>
    </properties>
@@ -21,24 +21,6 @@
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-engine</artifactId>
-            <version>${junit-jupiter.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-api</artifactId>
-            <version>${junit-jupiter.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <build>
@@ -67,7 +49,6 @@

    <properties>
        <maven.compiler.release>15</maven.compiler.release>
-        <assertj.version>3.17.2</assertj.version>
        <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
        <surefire.plugin.version>3.0.0-M3</surefire.plugin.version>
    </properties>
@@ -17,29 +17,11 @@
    </parent>

    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
-            <version>3.12.0</version>
+            <version>${commons-lang3.version}</version>
        </dependency>
-		<dependency>
-			<groupId>org.junit.jupiter</groupId>
-			<artifactId>junit-jupiter-engine</artifactId>
-			<version>${junit-jupiter.version}</version>
-			<scope>test</scope>
-		</dependency>
-		<dependency>
-			<groupId>org.junit.jupiter</groupId>
-			<artifactId>junit-jupiter-api</artifactId>
-			<version>${junit-jupiter.version}</version>
-			<scope>test</scope>
-		</dependency>
    </dependencies>

    <build>
@@ -50,37 +32,35 @@
                <version>${maven-compiler-plugin.version}</version>
                <configuration>
                    <release>${maven.compiler.release}</release>
-					<compilerArgs>--enable-preview</compilerArgs>
+                    <compilerArgs>--enable-preview</compilerArgs>
                    <source>${maven.compiler.source.version}</source>
                    <target>${maven.compiler.target.version}</target>
                </configuration>
            </plugin>
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-surefire-plugin</artifactId>
-				<version>${surefire.plugin.version}</version>
-				<configuration>
-					<argLine>--enable-preview</argLine>
-					<forkCount>1</forkCount>
-				</configuration>
-				<dependencies>
-					<dependency>
-						<groupId>org.apache.maven.surefire</groupId>
-						<artifactId>surefire-api</artifactId>
-						<version>${surefire.plugin.version}</version>
-					</dependency>
-				</dependencies>
-			</plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>${surefire.plugin.version}</version>
+                <configuration>
+                    <argLine>--enable-preview</argLine>
+                    <forkCount>1</forkCount>
+                </configuration>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.apache.maven.surefire</groupId>
+                        <artifactId>surefire-api</artifactId>
+                        <version>${surefire.plugin.version}</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
        </plugins>
    </build>

    <properties>
        <maven.compiler.source.version>16</maven.compiler.source.version>
        <maven.compiler.target.version>16</maven.compiler.target.version>
-		<maven.compiler.release>16</maven.compiler.release>
-		<maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
-		<surefire.plugin.version>3.0.0-M5</surefire.plugin.version>
-		<assertj.version>3.17.2</assertj.version>
+        <maven.compiler.release>16</maven.compiler.release>
+        <surefire.plugin.version>3.0.0-M5</surefire.plugin.version>
    </properties>

 </project>
@@ -1,3 +1,5 @@
 ### Relevant articles:

 - [Pattern Matching for Switch](https://www.baeldung.com/java-switch-pattern-matching)
+- [Introduction to HexFormat in Java 17](https://www.baeldung.com/java-hexformat)
+- [New Features in Java 17](https://www.baeldung.com/java-17-new-features)
@@ -16,27 +16,6 @@
        <relativePath>../../</relativePath>
    </parent>

-    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-		<dependency>
-			<groupId>org.junit.jupiter</groupId>
-			<artifactId>junit-jupiter-engine</artifactId>
-			<version>${junit-jupiter.version}</version>
-			<scope>test</scope>
-		</dependency>
-		<dependency>
-			<groupId>org.junit.jupiter</groupId>
-			<artifactId>junit-jupiter-api</artifactId>
-			<version>${junit-jupiter.version}</version>
-			<scope>test</scope>
-		</dependency>
-    </dependencies>
-
    <build>
        <plugins>
            <plugin>
@@ -50,32 +29,31 @@
                    <target>${maven.compiler.target.version}</target>
                </configuration>
            </plugin>
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-surefire-plugin</artifactId>
-				<version>${surefire.plugin.version}</version>
-				<configuration>
-					<argLine>--enable-preview</argLine>
-					<forkCount>1</forkCount>
-				</configuration>
-				<dependencies>
-					<dependency>
-						<groupId>org.apache.maven.surefire</groupId>
-						<artifactId>surefire-api</artifactId>
-						<version>${surefire.plugin.version}</version>
-					</dependency>
-				</dependencies>
-			</plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>${surefire.plugin.version}</version>
+                <configuration>
+                    <argLine>--enable-preview</argLine>
+                    <argLine>--enable-native-access=core.java</argLine>
+                    <forkCount>1</forkCount>
+                </configuration>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.apache.maven.surefire</groupId>
+                        <artifactId>surefire-api</artifactId>
+                        <version>${surefire.plugin.version}</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
        </plugins>
    </build>

    <properties>
        <maven.compiler.source.version>17</maven.compiler.source.version>
        <maven.compiler.target.version>17</maven.compiler.target.version>
-		<maven.compiler.release>17</maven.compiler.release>
-		<maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
-		<surefire.plugin.version>3.0.0-M5</surefire.plugin.version>
-		<assertj.version>3.17.2</assertj.version>
+        <maven.compiler.release>17</maven.compiler.release>
+        <surefire.plugin.version>3.0.0-M5</surefire.plugin.version>
    </properties>

 </project>
@@ -0,0 +1,20 @@
+package com.baeldung.features;
+
+import java.util.random.RandomGeneratorFactory;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+public class JEP356 {
+
+    public Stream<String> getAllAlgorithms() {
+        return RandomGeneratorFactory.all().map(RandomGeneratorFactory::name);
+    }
+
+    public IntStream getPseudoInts(String algorithm, int streamSize) {
+        // returns an IntStream with size @streamSize of random numbers generated using the @algorithm
+        // where the lower bound is 0 and the upper is 100 (exclusive)
+        return RandomGeneratorFactory.of(algorithm)
+                .create()
+                .ints(streamSize, 0,100);
+    }
+}
@@ -0,0 +1,28 @@
+package com.baeldung.features;
+
+import com.baeldung.features.JEP409.Circle;
+import com.baeldung.features.JEP409.Shape;
+import com.baeldung.features.JEP409.Triangle;
+
+public class JEP406 {
+
+    static record Human (String name, int age, String profession) {}
+
+    public String checkObject(Object obj) {
+        return switch (obj) {
+            case Human h -> "Name: %s, age: %s and profession: %s".formatted(h.name(), h.age(), h.profession());
+            case Circle c -> "This is a circle";
+            case Shape s -> "It is just a shape";
+            case null -> "It is null";
+            default -> "It is an object";
+        };
+    }
+
+    public String checkShape(Shape shape) {
+        return switch (shape) {
+            case Triangle t && (t.getNumberOfSides() != 3) -> "This is a weird triangle";
+            case Circle c && (c.getNumberOfSides() != 0) -> "This is a weird circle";
+            default -> "Just a normal shape";
+        };
+    }
+}
@@ -0,0 +1,38 @@
+package com.baeldung.features;
+
+public class JEP409 {
+
+    sealed interface Shape permits Rectangle, Circle, Square, Triangle {
+        int getNumberOfSides();
+    }
+
+    static final class Rectangle implements Shape {
+        @Override
+        public int getNumberOfSides() {
+            return 4;
+        }
+    }
+
+    static final class Circle implements Shape {
+        @Override
+        public int getNumberOfSides() {
+            return 0;
+        }
+    }
+
+    static final class Square implements Shape {
+        @Override
+        public int getNumberOfSides() {
+            return 4;
+        }
+    }
+
+    static non-sealed class Triangle implements Shape {
+
+        @Override
+        public int getNumberOfSides() {
+            return 3;
+        }
+    }
+
+}
@@ -0,0 +1,56 @@
+package com.baeldung.features;
+
+import jdk.incubator.foreign.CLinker;
+import jdk.incubator.foreign.FunctionDescriptor;
+import jdk.incubator.foreign.MemoryAddress;
+import jdk.incubator.foreign.SymbolLookup;
+
+import java.io.IOException;
+import java.lang.invoke.MethodType;
+
+import static jdk.incubator.foreign.ResourceScope.newImplicitScope;
+
+public class JEP412 {
+
+    private static final SymbolLookup libLookup;
+
+    static {
+        var resource = JEP412.class.getResource("/compile_c.sh");
+        try {
+            var process = new ProcessBuilder("sh", resource.getPath()).start();
+            while (process.isAlive()) {}
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        }
+
+        var path = JEP412.class.getResource("/print_name.so").getPath();
+        System.load(path);
+        libLookup = SymbolLookup.loaderLookup();
+    }
+
+    public String getPrintNameFormat(String name){
+
+        var printMethod = libLookup.lookup("printName");
+
+        if (printMethod.isPresent()) {
+            var methodReference = CLinker.getInstance()
+                .downcallHandle(
+                    printMethod.get(),
+                    MethodType.methodType(MemoryAddress.class, MemoryAddress.class),
+                    FunctionDescriptor.of(CLinker.C_POINTER, CLinker.C_POINTER)
+                );
+
+            try {
+                var nativeString = CLinker.toCString(name, newImplicitScope());
+                var invokeReturn = methodReference.invoke(nativeString.address());
+                var memoryAddress = (MemoryAddress) invokeReturn;
+                return CLinker.toJavaString(memoryAddress);
+            } catch (Throwable throwable) {
+                throw new RuntimeException(throwable);
+            }
+        }
+        throw new RuntimeException("printName function not found.");
+    }
+}
+
+
@@ -0,0 +1,27 @@
+package com.baeldung.features;
+
+import jdk.incubator.vector.FloatVector;
+import jdk.incubator.vector.VectorSpecies;
+
+public class JEP414 {
+
+    private static final VectorSpecies<Float> SPECIES = FloatVector.SPECIES_PREFERRED;
+
+
+    public void newVectorComputation(float[] a, float[] b, float[] c) {
+        for (var i = 0; i < a.length; i += SPECIES.length()) {
+            var m = SPECIES.indexInRange(i, a.length);
+            var va = FloatVector.fromArray(SPECIES, a, i, m);
+            var vb = FloatVector.fromArray(SPECIES, b, i, m);
+            var vc = va.mul(vb);
+            vc.intoArray(c, i, m);
+        }
+    }
+
+    public void commonVectorComputation(float[] a, float[] b, float[] c) {
+        for (var i = 0; i < a.length; i ++) {
+            c[i] = a[i] * b[i];
+        }
+    }
+
+}
@@ -0,0 +1,4 @@
+module core.java {
+    requires jdk.incubator.vector;
+    requires jdk.incubator.foreign;
+}
@@ -0,0 +1,9 @@
+#!/bin/bash
+
+SCRIPTPATH="$( cd -- "$(dirname "$0")" >/dev/null 2>&1 ; pwd -P )"
+
+gcc -c -fPIC $SCRIPTPATH/print_name.c
+gcc -shared -rdynamic -o print_name.so print_name.o
+
+mv print_name.so $SCRIPTPATH/
+mv print_name.o $SCRIPTPATH/
@@ -0,0 +1,8 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+char* printName(char *name) {
+    char* newString = (char*)malloc((15 + sizeof(name))*sizeof(char));
+    sprintf(newString, "Your name is %s", name);
+    return newString;
+}
@@ -0,0 +1,19 @@
+package com.baeldung.features;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class JEP356UnitTest {
+
+    @Test
+    void getPseudoInts_whenUsingAlgorithmXoroshiro128PlusPlus_shouldReturnStreamOfRandomInteger() {
+        var algorithm = "Xoshiro256PlusPlus";
+        var streamSize = 100;
+
+        JEP356 jep356 = new JEP356();
+
+        jep356.getPseudoInts(algorithm, streamSize)
+            .forEach(value -> assertThat(value).isLessThanOrEqualTo(99));
+    }
+}
@@ -0,0 +1,33 @@
+package com.baeldung.features;
+
+import com.baeldung.features.JEP406.Human;
+import com.baeldung.features.JEP409.Square;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class JEP406UnitTest {
+
+    @Test
+    void checkObject_shouldMatchWithHuman() {
+        var jep406 = new JEP406();
+
+        var human = new Human("John", 31, "Developer");
+
+        var checkResult = jep406.checkObject(human);
+
+        assertEquals("Name: John, age: 31 and profession: Developer", checkResult);
+    }
+
+    @Test
+    void checkShape_shouldMatchWithShape() {
+        var jep406 = new JEP406();
+
+        var square = new Square();
+
+        var checkResult = jep406.checkShape(square);
+
+        assertEquals("Just a normal shape", checkResult);
+    }
+
+}
@@ -0,0 +1,39 @@
+package com.baeldung.features;
+
+import com.baeldung.features.JEP409.*;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+
+class JEP409UnitTest {
+
+    static class WeirdTriangle extends Triangle {
+        @Override public int getNumberOfSides() {
+            return 40;
+        }
+    }
+
+    @Test
+    void testSealedClass_shouldInvokeRightClass() {
+
+        Shape shape = spy(new WeirdTriangle());
+
+        int numberOfSides = getNumberOfSides(shape);
+
+        assertEquals(40, numberOfSides);
+        verify(shape).getNumberOfSides();
+    }
+
+    int getNumberOfSides(Shape shape) {
+        return switch (shape) {
+            case WeirdTriangle t -> t.getNumberOfSides();
+            case Circle c -> c.getNumberOfSides();
+            case Triangle t -> t.getNumberOfSides();
+            case Rectangle r -> r.getNumberOfSides();
+            case Square s -> s.getNumberOfSides();
+        };
+    }
+}
@@ -0,0 +1,17 @@
+package com.baeldung.features;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class JEP412UnitTest {
+
+    @Test
+    void getPrintNameFormat_whenPassingAName_shouldReceiveItFormatted() {
+        var jep412 = new JEP412();
+
+        var formattedName = jep412.getPrintNameFormat("John");
+
+        assertEquals("Your name is John", formattedName);
+    }
+}
@@ -0,0 +1,38 @@
+package com.baeldung.features;
+
+import org.junit.jupiter.api.Test;
+
+import static java.util.stream.Collectors.toList;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class JEP414UnitTest {
+
+    @Test
+    void vectorComputation_shouldMultiplyVectors() {
+        var jep414 = new JEP414();
+
+        float[] a = initArray(100);
+        float[] b = initArray(100);
+        float[] c = new float[100];
+        float[] d = new float[100];
+
+        jep414.newVectorComputation(a, b, c);
+        jep414.commonVectorComputation(a, b, d);
+
+        for (int i = 0; i < a.length; i++) {
+            assertEquals(c[i], d[i]);
+        }
+    }
+
+    private float[] initArray(int size) {
+        final var jep356 = new JEP356();
+        final var values = new float[size];
+        final var pseudoInts = jep356.getPseudoInts("Xoshiro256PlusPlus", size).mapToObj(Float::valueOf).collect(toList());
+
+        for (int i = 0; i < pseudoInts.size(); i++) {
+            values[i] = pseudoInts.get(i);
+        }
+
+        return values;
+    }
+}
@@ -0,0 +1,23 @@
+package com.baeldung.hexformat;
+
+import java.util.HexFormat;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ByteHexadecimalConversionUnitTest {
+
+    private HexFormat hexFormat = HexFormat.of();
+
+    @Test
+    void givenInitialisedHexFormat_whenHexStringIsPassed_thenByteArrayRepresentationIsReturned() {
+        byte[] hexBytes = hexFormat.parseHex("ABCDEF0123456789");
+        assertArrayEquals(new byte[] { -85, -51, -17, 1, 35, 69, 103, -119 }, hexBytes);
+    }
+
+    @Test
+    void givenInitialisedHexFormat_whenByteArrayIsPassed_thenHexStringRepresentationIsReturned() {
+        String bytesAsString = hexFormat.formatHex(new byte[] { -85, -51, -17, 1, 35, 69, 103, -119});
+        assertEquals("abcdef0123456789", bytesAsString);
+    }
+}
@@ -0,0 +1,22 @@
+package com.baeldung.hexformat;
+
+import java.util.HexFormat;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class PrimitiveTypeHexadecimalConversionUnitTest {
+
+    private HexFormat hexFormat = HexFormat.of();
+
+    @Test
+    void givenInitialisedHexFormat_whenPrimitiveByteIsPassed_thenHexStringRepresentationIsReturned() {
+        String fromByte = hexFormat.toHexDigits((byte)64);
+        assertEquals("40", fromByte);
+    }
+
+    @Test
+    void givenInitialisedHexFormat_whenPrimitiveLongIsPassed_thenHexStringRepresentationIsReturned() {
+        String fromLong = hexFormat.toHexDigits(1234_5678_9012_3456L);
+        assertEquals("000462d53c8abac0", fromLong);
+    }
+}
@@ -0,0 +1,15 @@
+package com.baeldung.hexformat;
+
+import java.util.HexFormat;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class StringFormattingUnitTest {
+
+    private HexFormat hexFormat = HexFormat.of().withPrefix("[").withSuffix("]").withDelimiter(", ");
+
+    @Test
+    public void givenInitialisedHexFormatWithFormattedStringOptions_whenByteArrayIsPassed_thenHexStringRepresentationFormattedCorrectlyIsReturned() {
+        assertEquals("[48], [0c], [11]", hexFormat.formatHex(new byte[] {72, 12, 17}));
+    }
+}
@@ -0,0 +1,40 @@
+package com.baeldung.hexformat;
+
+import java.util.HexFormat;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class UppercaseLowercaseOutputUnitTest {
+
+    @Test
+    public void givenInitialisedHexFormat_whenByteArrayIsPassed_thenLowerCaseHexStringRepresentationIsReturned() {
+        HexFormat hexFormat = HexFormat.of();
+        String bytesAsString = hexFormat.formatHex(new byte[] { -85, -51, -17, 1, 35, 69, 103, -119});
+        assertTrue(isLowerCase(bytesAsString));
+    }
+
+    @Test
+    public void givenInitialisedHexFormatWithUpperCaseOption_whenByteArrayIsPassed_thenLowerCaseHexStringRepresentationIsReturned() {
+        HexFormat hexFormat = HexFormat.of().withUpperCase();
+        String bytesAsString = hexFormat.formatHex(new byte[] { -85, -51, -17, 1, 35, 69, 103, -119});
+        assertTrue(isUpperCase(bytesAsString));
+    }
+
+    private boolean isLowerCase(String str) {
+        char[] charArray = str.toCharArray();
+        for (int i=0; i < charArray.length; i++) {
+            if (Character.isUpperCase(charArray[i]))
+                return false;
+        }
+        return true;
+    }
+
+    private boolean isUpperCase(String str) {
+        char[] charArray = str.toCharArray();
+        for (int i=0; i < charArray.length; i++) {
+            if (Character.isLowerCase(charArray[i]))
+                return false;
+        }
+        return true;
+    }
+}
@@ -20,17 +20,10 @@
            <artifactId>icu4j</artifactId>
            <version>${icu.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <properties>
        <icu.version>64.2</icu.version>
-        <assertj.version>3.12.2</assertj.version>
    </properties>

 </project>
@@ -25,12 +25,6 @@
            <artifactId>joda-time</artifactId>
            <version>${joda-time.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
@@ -63,8 +57,6 @@
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <joda-time.version>2.10</joda-time.version>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
    </properties>

 </project>
@@ -25,12 +25,6 @@
            <artifactId>joda-time</artifactId>
            <version>${joda-time.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
@@ -64,8 +58,6 @@
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <joda-time.version>2.10</joda-time.version>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
    </properties>

 </project>
@@ -31,13 +31,6 @@
            <version>${lombok.version}</version>
            <scope>provided</scope>
        </dependency>
-        <!-- test scoped -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <build>
@@ -50,11 +43,4 @@
        </resources>
    </build>

-    <properties>
-        <!-- util -->
-        <commons-collections4.version>4.1</commons-collections4.version>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
-    </properties>
-
 </project>
@@ -21,12 +21,6 @@
            <version>${awaitility.version}</version>
            <scope>test</scope>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
@@ -68,8 +62,6 @@
    </pluginRepositories>

    <properties>
-        <!-- testing -->
-        <assertj.version>3.10.0</assertj.version>
        <awaitility.version>1.7.0</awaitility.version>
        <maven.compiler.source>1.9</maven.compiler.source>
        <maven.compiler.target>1.9</maven.compiler.target>
@@ -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();
@@ -20,12 +20,6 @@
            <artifactId>rxjava</artifactId>
            <version>${rxjava.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.junit.platform</groupId>
            <artifactId>junit-platform-runner</artifactId>
@@ -156,8 +150,6 @@

    <properties>
        <rxjava.version>3.0.0</rxjava.version>
-        <!-- testing -->
-        <assertj.version>3.10.0</assertj.version>
        <awaitility.version>4.0.2</awaitility.version>
        <maven.compiler.source>1.9</maven.compiler.source>
        <maven.compiler.target>1.9</maven.compiler.target>
@@ -21,12 +21,6 @@
            <version>${awaitility.version}</version>
            <scope>test</scope>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
@@ -78,14 +72,10 @@
    </pluginRepositories>

    <properties>
-        <!-- testing -->
-        <assertj.version>3.10.0</assertj.version>
        <awaitility.version>1.7.0</awaitility.version>
        <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>
-        <commons-collections3.version>3.2.2</commons-collections3.version>
    </properties>

 </project>
@@ -1,7 +1,7 @@
 <?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">
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <artifactId>core-java-annotations</artifactId>
    <version>0.1.0-SNAPSHOT</version>
@@ -14,19 +14,6 @@
        <version>0.0.1-SNAPSHOT</version>
    </parent>

-    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj-core.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
-    <properties>
-        <assertj-core.version>3.10.0</assertj-core.version>
-    </properties>
-
    <build>
        <finalName>core-java-annotations</finalName>
        <resources>
@@ -37,4 +24,4 @@
        </resources>
    </build>

-</project>
+</project>
@@ -24,12 +24,6 @@
            <artifactId>jmh-generator-annprocess</artifactId>
            <version>${jmh-generator.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>3.19.0</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

 </project>
@@ -19,32 +19,18 @@
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
        </dependency>
-
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj-core.version}</version>
-            <scope>test</scope>
-        </dependency>
-
        <dependency>
            <groupId>org.openjdk.jmh</groupId>
            <artifactId>jmh-core</artifactId>
-            <version>${jmh.version}</version>
+            <version>${jmh-core.version}</version>
        </dependency>
-
        <dependency>
            <groupId>org.openjdk.jmh</groupId>
            <artifactId>jmh-generator-annprocess</artifactId>
-            <version>${jmh.version}</version>
+            <version>${jmh-generator.version}</version>
        </dependency>
    </dependencies>

-    <properties>
-        <assertj-core.version>3.10.0</assertj-core.version>
-        <jmh.version>1.33</jmh.version>
-    </properties>
-
    <build>
        <plugins>
            <plugin>
@@ -30,12 +30,6 @@
            <artifactId>jmh-generator-annprocess</artifactId>
            <version>${jmh-generator.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj-core.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <build>
@@ -67,7 +61,6 @@

    <properties>
        <shade.plugin.version>3.2.0</shade.plugin.version>
-        <assertj-core.version>3.10.0</assertj-core.version>
    </properties>

 </project>
@@ -36,13 +36,6 @@
            <artifactId>jmh-generator-annprocess</artifactId>
            <version>${jmh-generator.version}</version>
        </dependency>
-        <!-- Testing -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj-core.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <build>
@@ -75,7 +68,6 @@
    <properties>
        <shade.plugin.version>3.2.0</shade.plugin.version>
        <guava.version>28.2-jre</guava.version>
-        <assertj-core.version>3.10.0</assertj-core.version>
    </properties>

 </project>
@@ -15,12 +15,6 @@
    </parent>

    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.openjdk.jmh</groupId>
            <artifactId>jmh-core</artifactId>
@@ -33,8 +27,4 @@
        </dependency>
    </dependencies>

-    <properties>
-        <assertj.version>3.11.1</assertj.version>
-    </properties>
-
 </project>
@@ -34,12 +34,6 @@
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.junit.platform</groupId>
            <artifactId>junit-platform-runner</artifactId>
@@ -50,8 +44,6 @@

    <properties>
        <eclipse.collections.version>7.1.0</eclipse.collections.version>
-        <commons-collections4.version>4.1</commons-collections4.version>
-        <assertj.version>3.11.1</assertj.version>
        <commons-exec.version>1.3</commons-exec.version>
    </properties>

@@ -11,7 +11,7 @@
 - [Performance of contains() in a HashSet vs ArrayList](https://www.baeldung.com/java-hashset-arraylist-contains-performance)
 - [Fail-Safe Iterator vs Fail-Fast Iterator](https://www.baeldung.com/java-fail-safe-vs-fail-fast-iterator)
 - [Quick Guide to the Java Stack](https://www.baeldung.com/java-stack)
- [Convert an Array of Primitives to a List](https://www.baeldung.com/java-primitive-array-to-list)
 - [A Guide to BitSet in Java](https://www.baeldung.com/java-bitset)
 - [Get the First Key and Value From a HashMap](https://www.baeldung.com/java-hashmap-get-first-entry)
 - [Performance of removeAll() in a HashSet](https://www.baeldung.com/java-hashset-removeall-performance)
+- More articles: [[<-- prev]](/core-java-modules/core-java-collections-2) [[next -->]](/core-java-modules/core-java-collections-4)
@@ -25,12 +25,6 @@
            <artifactId>jmh-core</artifactId>
            <version>${jmh-core.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
@@ -39,7 +33,6 @@
    </dependencies>

    <properties>
-        <assertj.version>3.11.1</assertj.version>
        <jol-core.version>0.10</jol-core.version>
    </properties>

@@ -1,4 +1,4 @@
-package com.baeldung.stack;
+package com.baeldung.collections.stack;

 import org.junit.Test;

@@ -14,17 +14,4 @@
        <version>0.0.1-SNAPSHOT</version>
    </parent>

-    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
-    <properties>
-        <assertj.version>3.19.0</assertj.version>
-    </properties>
-
 </project>
@@ -0,0 +1,5 @@
+package com.baeldung.collections.mulipletypesinmap;
+
+public interface DynamicTypeValue {
+    String valueDescription();
+}
@@ -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));
+    }
+
+}
@@ -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));
+    }
+
+}
@@ -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);
+    }
+}
@@ -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}");
+    }
+}
@@ -20,17 +20,6 @@
            <artifactId>commons-collections4</artifactId>
            <version>${commons-collections4.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

-    <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
-        <assertj.version>3.11.1</assertj.version>
-    </properties>
-
 </project>
@@ -20,12 +20,6 @@
            <artifactId>commons-collections4</artifactId>
            <version>${commons-collections4.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
@@ -34,9 +28,4 @@
        </dependency>
    </dependencies>

-    <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
-        <assertj.version>3.11.1</assertj.version>
-    </properties>
-
 </project>
@@ -26,12 +26,6 @@
            <version>${guava.version}</version>
            <scope>compile</scope>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>net.sf.trove4j</groupId>
            <artifactId>trove4j</artifactId>
@@ -60,8 +54,6 @@
    </dependencies>

    <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
-        <assertj.version>3.11.1</assertj.version>
        <trove4j.version>3.0.2</trove4j.version>
        <fastutil.version>8.1.0</fastutil.version>
        <colt.version>1.2.0</colt.version>
@@ -25,17 +25,6 @@
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

-    <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
-        <assertj.version>3.11.1</assertj.version>
-    </properties>
-
 </project>
@@ -51,22 +51,14 @@
            <version>${avaitility.version}</version>
            <scope>test</scope>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <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>
        <fastutil.version>8.1.0</fastutil.version>
-        <assertj.version>3.11.1</assertj.version>
    </properties>

 </project>
@@ -4,3 +4,5 @@ This module contains articles about Map data structures in Java.

 ### Relevant Articles: 
 - [Using a Custom Class as a Key in a Java HashMap](https://www.baeldung.com/java-custom-class-map-key)
+- [Nested HashMaps Examples in Java](https://www.baeldung.com/java-nested-hashmaps)
+- [Java HashMap With Different Value Types](https://www.baeldung.com/java-hashmap-different-value-types)
@@ -1,34 +1,49 @@
 <?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>core-java-collections-maps-4</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
-    <name>core-java-collections-maps-4</name>
-    <packaging>jar</packaging>
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<artifactId>core-java-collections-maps-4</artifactId>
+	<version>0.1.0-SNAPSHOT</version>
+	<name>core-java-collections-maps-4</name>
+	<packaging>jar</packaging>

-    <parent>
-        <groupId>com.baeldung.core-java-modules</groupId>
-        <artifactId>core-java-modules</artifactId>
-        <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../pom.xml</relativePath>
-    </parent>
+	<parent>
+		<groupId>com.baeldung.core-java-modules</groupId>
+		<artifactId>core-java-modules</artifactId>
+		<version>0.0.1-SNAPSHOT</version>
+		<relativePath>../pom.xml</relativePath>
+	</parent>
+	
+	<properties>
+	    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.source>1.8</maven.compiler.source>
+		<maven.compiler.target>1.8</maven.compiler.target>
+	</properties>

-    <build>
-        <pluginManagement>
-            <plugins>
-                <plugin>
-                    <groupId>org.apache.maven.plugins</groupId>
-                    <artifactId>maven-surefire-plugin</artifactId>
-                    <version>3.0.0-M5</version>
-                    <configuration>
-                        <!-- those tests are not made for CI purposes, but for manual testing -->
-                        <groups>!performance</groups>
-                    </configuration>
-                </plugin>
-            </plugins>
-        </pluginManagement>
-    </build>
+	<dependencies>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>${junit.version}</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>

-</project>
+	<build>
+		<pluginManagement>
+			<plugins>
+				<plugin>
+					<groupId>org.apache.maven.plugins</groupId>
+					<artifactId>maven-surefire-plugin</artifactId>
+					<version>3.0.0-M5</version>
+					<configuration>
+						<!-- those tests are not made for CI purposes, but for manual testing -->
+						<groups>!performance</groups>
+					</configuration>
+				</plugin>
+			</plugins>
+		</pluginManagement>
+	</build>
+
+</project>
@@ -0,0 +1,32 @@
+package com.baeldung.nestedhashmaps;
+
+public class Address {
+
+    private Integer addressId;
+    private String addressLocation;
+
+    public Address() {
+    }
+
+    public Address(Integer addressId, String addressLocation) {
+        this.addressId = addressId;
+        this.addressLocation = addressLocation;
+    }
+
+    public Integer getAddressId() {
+        return addressId;
+    }
+
+    public void setAddressId(Integer addressId) {
+        this.addressId = addressId;
+    }
+
+    public String getAddressLocation() {
+        return addressLocation;
+    }
+
+    public void setAddressLocation(String addressLocation) {
+        this.addressLocation = addressLocation;
+    }
+
+}
@@ -0,0 +1,43 @@
+package com.baeldung.nestedhashmaps;
+
+public class Employee {
+
+    private Integer employeeId;
+    private Address address;
+    private String employeeName;
+
+    public Employee() {
+        super();
+    }
+
+    public Employee(Integer employeeId, Address address, String employeeName) {
+        this.employeeId = employeeId;
+        this.address = address;
+        this.employeeName = employeeName;
+    }
+
+    public Integer getEmployeeId() {
+        return employeeId;
+    }
+
+    public void setEmployeeId(Integer employeeId) {
+        this.employeeId = employeeId;
+    }
+
+    public Address getAddress() {
+        return address;
+    }
+
+    public void setAddress(Address address) {
+        this.address = address;
+    }
+
+    public String getEmployeeName() {
+        return employeeName;
+    }
+
+    public void setEmployeeName(String employeeName) {
+        this.employeeName = employeeName;
+    }
+
+}
@@ -0,0 +1,57 @@
+package com.baeldung.nestedhashmaps;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.stream.Collectors;
+
+public class MapsUtil {
+
+    MapsUtil() {
+        super();
+    }
+
+    public Map<Integer, String> buildInnerMap(List<String> batterList) {
+        Map<Integer, String> innerBatterMap = new HashMap<Integer, String>();
+
+        int index = 1;
+        for (String item : batterList) {
+            innerBatterMap.put(index, item);
+            index++;
+        }
+
+        return innerBatterMap;
+    }
+
+    public Map<Integer, Map<String, String>> createNestedMapfromStream(List<Employee> listEmployee) {
+        Map<Integer, Map<String, String>> employeeAddressMap = listEmployee.stream()
+                .collect(Collectors.groupingBy(e -> e.getAddress().getAddressId(),
+                        Collectors.toMap(f -> f.getAddress().getAddressLocation(), Employee::getEmployeeName)));
+        return employeeAddressMap;
+    }
+
+    public Map<Integer, Map<Integer, Address>> createNestedObjectMap(List<Employee> listEmployee) {
+        Map<Integer, Map<Integer, Address>> employeeMap = new HashMap<>();
+
+        employeeMap = listEmployee.stream().collect(Collectors.groupingBy((Employee emp) -> emp.getEmployeeId(),
+                Collectors.toMap((Employee emp) -> emp.getAddress().getAddressId(), fEmpObj -> fEmpObj.getAddress())));
+
+        return employeeMap;
+    }
+
+    public Map<String, String> flattenMap(Map<?, ?> source) {
+        Map<String, String> converted = new HashMap<>();
+
+        for (Entry<?, ?> entry : source.entrySet()) {
+            if (entry.getValue() instanceof Map) {
+                flattenMap((Map<String, Object>) entry.getValue())
+                        .forEach((key, value) -> converted.put(entry.getKey() + "." + key, value));
+            } else {
+                converted.put(entry.getKey().toString(), entry.getValue().toString());
+            }
+        }
+        return converted;
+    }
+
+}
@@ -0,0 +1,118 @@
+package com.baeldung.nestedhashmaps;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+
+import java.util.List;
+
+public class NestedHashMapExamplesClass {
+    public static void main(String[] args) {
+
+        MapsUtil mUtil = new MapsUtil();
+
+        List<String> batterList = new ArrayList<>();
+        Map<String, Map<Integer, String>> outerBakedGoodsMap = new HashMap<>();
+        Map<String, Map<Integer, String>> outerBakedGoodsMap2 = new HashMap<>();
+        Map<String, Map<Integer, String>> outerBakedGoodsMap3 = new HashMap<>();
+        Map<String, Map<Integer, String>> outerBakedGoodsMap4 = new HashMap<>();
+
+        batterList.add("Mulberry");
+        batterList.add("Cranberry");
+        batterList.add("Blackberry");
+        batterList.add("Mixed fruit");
+        batterList.add("Orange");
+
+        outerBakedGoodsMap.put("Cake", mUtil.buildInnerMap(batterList));
+
+        batterList.clear();
+        batterList.add("Candy");
+        batterList.add("Dark Chocolate");
+        batterList.add("Chocolate");
+        batterList.add("Jam filled");
+        batterList.add("Pineapple");
+
+        outerBakedGoodsMap.put("Donut", mUtil.buildInnerMap(batterList));
+
+        outerBakedGoodsMap2.put("Eclair", mUtil.buildInnerMap(batterList));
+        outerBakedGoodsMap2.put("Donut", mUtil.buildInnerMap(batterList));
+
+        outerBakedGoodsMap3.put("Cake", mUtil.buildInnerMap(batterList));
+        batterList.clear();
+        batterList.add("Banana");
+        batterList.add("Red Velvet");
+        batterList.add("Blackberry");
+        batterList.add("Passion fruit");
+        batterList.add("Kiwi");
+
+        outerBakedGoodsMap3.put("Donut", mUtil.buildInnerMap(batterList));
+
+        outerBakedGoodsMap4.putAll(outerBakedGoodsMap);
+
+        System.out.println(outerBakedGoodsMap.equals(outerBakedGoodsMap2));
+        System.out.println(outerBakedGoodsMap.equals(outerBakedGoodsMap3));
+        System.out.println(outerBakedGoodsMap.equals(outerBakedGoodsMap4));
+
+        outerBakedGoodsMap.get("Cake")
+            .put(6, "Cranberry");
+        System.out.println(outerBakedGoodsMap);
+
+        outerBakedGoodsMap.get("Cake")
+            .remove(5);
+        System.out.println(outerBakedGoodsMap);
+
+        outerBakedGoodsMap.put("Eclair", new HashMap<Integer, String>() {
+            {
+                put(1, "Dark Chocolate");
+            }
+        });
+
+        System.out.println(outerBakedGoodsMap);
+        outerBakedGoodsMap.remove("Eclair");
+        System.out.println(outerBakedGoodsMap);
+        System.out.println("Baked Goods Map Flattened: " + mUtil.flattenMap(outerBakedGoodsMap));
+
+        // Employees Map
+        List<Employee> listEmployee = new ArrayList<Employee>();
+
+        listEmployee.add(new Employee(1, new Address(124, "Timbuktoo"), "Thorin Oakenshield"));
+        listEmployee.add(new Employee(2, new Address(100, "Misty Lanes"), "Balin"));
+        listEmployee.add(new Employee(3, new Address(156, "Bramles Lane"), "Bofur"));
+        listEmployee.add(new Employee(4, new Address(200, "Bag End"), "Bilbo Baggins"));
+        listEmployee.add(new Employee(5, new Address(23, "Rivendell"), "Elrond"));
+
+        Map<Integer, Map<String, String>> employeeAddressMap = mUtil.createNestedMapfromStream(listEmployee);
+
+        Map<Integer, Map<Integer, Address>> employeeMap = mUtil.createNestedObjectMap(listEmployee);
+        Map<Integer, Map<Integer, Address>> employeeMap2 = mUtil.createNestedObjectMap(listEmployee);
+
+        listEmployee.clear();
+        listEmployee.add(new Employee(1, new Address(500, "Timbuktoo"), "Thorin Oakenshield"));
+        listEmployee.add(new Employee(2, new Address(600, "Misty Lanes"), "Balin"));
+        listEmployee.add(new Employee(3, new Address(700, "Bramles Lane"), "Bofur"));
+        listEmployee.add(new Employee(4, new Address(800, "Bag End"), "Bilbo Baggins"));
+        listEmployee.add(new Employee(5, new Address(900, "Rivendell"), "Elrond"));
+
+        Map<Integer, Map<String, String>> employeeAddressMap1 = mUtil.createNestedMapfromStream(listEmployee);
+
+        Map<Integer, Map<Integer, Address>> employeeMap1 = mUtil.createNestedObjectMap(listEmployee);
+
+        System.out.println(employeeMap.equals(employeeMap1));
+        System.out.println(employeeMap.equals(employeeMap2));
+
+        for (Map.Entry<String, Map<Integer, String>> outerBakedGoodsMapEntrySet : outerBakedGoodsMap.entrySet()) {
+            Map<Integer, String> valueMap = outerBakedGoodsMapEntrySet.getValue();
+            System.out.println(valueMap.entrySet());
+        }
+
+        for (Map.Entry<Integer, Map<String, String>> employeeEntrySet : employeeAddressMap.entrySet()) {
+            Map<String, String> valueMap = employeeEntrySet.getValue();
+            System.out.println(valueMap.entrySet());
+        }
+
+        System.out.println("Employee Address Map Flattened: " + mUtil.flattenMap(employeeAddressMap));
+
+        System.out.println(employeeAddressMap.equals(employeeAddressMap1));
+    }
+
+}
@@ -0,0 +1,243 @@
+package com.baeldung.nestedhashmaps;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNotSame;
+import static org.junit.Assert.assertThat;
+import org.hamcrest.collection.IsMapContaining;
+
+public class NestedHashMapExamplesClassUnitTest {
+    private MapsUtil mUtil = new MapsUtil();
+    private List<String> batterList = new ArrayList<>();
+    private List<Employee> listEmployee = new ArrayList<Employee>();
+    private Map<String, Map<Integer, String>> actualBakedGoodsMap = new HashMap<>();
+    private Map<Integer, Map<String, String>> actualEmployeeAddressMap = new HashMap<>();
+    private Map<Integer, Map<Integer, Address>> actualEmployeeMap = new HashMap<>();
+
+    @Test
+    public void whenCreateNestedHashMap_thenNestedMap() {
+        assertThat(mUtil.buildInnerMap(batterList), is(notNullValue()));
+        Assert.assertEquals(actualBakedGoodsMap.keySet().size(), 2);
+        Assert.assertThat(actualBakedGoodsMap, IsMapContaining.hasValue(equalTo(mUtil.buildInnerMap(batterList))));
+    }
+
+    private Map<Integer, Map<String, String>> setup() {
+        Map<Integer, Map<String, String>> expectedMap = new HashMap<>();
+        expectedMap.put(Integer.valueOf(100), new HashMap<String, String>() {
+            {
+                put("Misty Lanes", "Balin");
+            }
+        });
+        expectedMap.put(Integer.valueOf(200), new HashMap<String, String>() {
+            {
+                put("Bag End", "Bilbo Baggins");
+            }
+        });
+        expectedMap.put(Integer.valueOf(156), new HashMap<String, String>() {
+            {
+                put("Brambles Lane", "Bofur");
+            }
+        });
+        expectedMap.put(Integer.valueOf(124), new HashMap<String, String>() {
+            {
+                put("Timbuktoo", "Thorin Oakenshield");
+            }
+        });
+        expectedMap.put(Integer.valueOf(23), new HashMap<String, String>() {
+            {
+                put("Rivendell", "Elrond");
+            }
+        });
+
+        return expectedMap;
+    }
+
+    @Test
+    public void whenCreateNestedHashMapwithStreams_thenNestedMap() {
+
+        Map<Integer, Map<String, String>> expectedMap = setup();
+
+        assertThat(actualEmployeeAddressMap, equalTo(expectedMap));
+    }
+
+    @Test
+    public void whenCompareTwoHashMapswithDifferenctValues_usingEquals_thenFail() {
+        Map<String, Map<Integer, String>> outerBakedGoodsMap2 = new HashMap<>();
+        outerBakedGoodsMap2.put("Eclair", mUtil.buildInnerMap(batterList));
+        outerBakedGoodsMap2.put("Donut", mUtil.buildInnerMap(batterList));
+        assertNotEquals(outerBakedGoodsMap2, actualBakedGoodsMap);
+
+        Map<String, Map<Integer, String>> outerBakedGoodsMap3 = new HashMap<String, Map<Integer, String>>();
+        outerBakedGoodsMap3.put("Cake", mUtil.buildInnerMap(batterList));
+        batterList = new ArrayList<>();
+        batterList = Arrays.asList("Banana", "Red Velvet", "Blackberry", "Passion fruit", "Kiwi");
+
+        outerBakedGoodsMap3.put("Donut", mUtil.buildInnerMap(batterList));
+
+        assertNotEquals(outerBakedGoodsMap2, actualBakedGoodsMap);
+
+        listEmployee.clear();
+        listEmployee.add(new Employee(1, new Address(500, "Timbuktoo"), "Thorin Oakenshield"));
+        listEmployee.add(new Employee(2, new Address(600, "Misty Lanes"), "Balin"));
+        listEmployee.add(new Employee(3, new Address(700, "Bramles Lane"), "Bofur"));
+        listEmployee.add(new Employee(4, new Address(800, "Bag End"), "Bilbo Baggins"));
+        listEmployee.add(new Employee(5, new Address(900, "Rivendell"), "Elrond"));
+
+        Map<Integer, Map<String, String>> employeeAddressMap1 = mUtil.createNestedMapfromStream(listEmployee);
+
+        Map<Integer, Map<Integer, Address>> employeeMap1 = mUtil.createNestedObjectMap(listEmployee);
+
+        assertNotEquals(employeeAddressMap1, actualEmployeeAddressMap);
+
+        assertNotEquals(employeeMap1, actualEmployeeMap);
+    }
+
+    @Test
+    public void whencomparingDifferentObjectValuesUsingEquals_thenFail() {
+        listEmployee.clear();
+        listEmployee.add(new Employee(1, new Address(124, "Timbuktoo"), "Thorin Oakenshield"));
+        listEmployee.add(new Employee(2, new Address(100, "Misty Lanes"), "Balin"));
+        listEmployee.add(new Employee(3, new Address(156, "Brambles Lane"), "Bofur"));
+        listEmployee.add(new Employee(4, new Address(200, "Bag End"), "Bilbo Baggins"));
+        listEmployee.add(new Employee(5, new Address(23, "Rivendell"), "Elrond"));
+
+        Map<Integer, Map<Integer, Object>> employeeMap1 = listEmployee.stream().collect(Collectors.groupingBy(
+                (Employee emp) -> emp.getEmployeeId(),
+                Collectors.toMap((Employee emp) -> emp.getAddress().getAddressId(), fEmpObj -> fEmpObj.getAddress())));
+
+        assertNotSame(employeeMap1, actualEmployeeMap);
+        assertNotEquals(employeeMap1, actualEmployeeMap);
+
+        Map<Integer, Map<Integer, Address>> expectedMap = setupAddressObjectMap();
+        assertNotSame(expectedMap, actualEmployeeMap);
+        assertNotEquals(expectedMap, actualEmployeeMap);
+
+    }
+
+    @Test
+    public void whenCompareTwoHashMapsUsingEquals_thenSuccess() {
+        Map<String, Map<Integer, String>> outerBakedGoodsMap4 = new HashMap<>();
+        outerBakedGoodsMap4.putAll(actualBakedGoodsMap);
+
+        assertEquals(actualBakedGoodsMap, outerBakedGoodsMap4);
+
+        Map<Integer, Map<Integer, Address>> employeeMap1 = new HashMap<>();
+        employeeMap1.putAll(actualEmployeeMap);
+        assertEquals(actualEmployeeMap, employeeMap1);
+    }
+
+    @Test
+    public void whenAddElementinHashMaps_thenSuccess() {
+        assertEquals(actualBakedGoodsMap.get("Cake").size(), 5);
+        actualBakedGoodsMap.get("Cake").put(6, "Cranberry");
+        assertEquals(actualBakedGoodsMap.get("Cake").size(), 6);
+    }
+
+    @Test
+    public void whenDeleteElementinHashMaps_thenSuccess() {
+        assertNotEquals(actualBakedGoodsMap.get("Cake").get(5), null);
+        actualBakedGoodsMap.get("Cake").remove(5);
+        assertEquals(actualBakedGoodsMap.get("Cake").get(5), null);
+
+        actualBakedGoodsMap.put("Eclair", new HashMap<Integer, String>() {
+            {
+                put(1, "Dark Chocolate");
+            }
+        });
+
+        assertNotEquals(actualBakedGoodsMap.get("Eclair").get(1), null);
+        actualBakedGoodsMap.get("Eclair").remove(1);
+        assertEquals(actualBakedGoodsMap.get("Eclair").get(1), null);
+
+        actualBakedGoodsMap.put("Eclair", new HashMap<Integer, String>() {
+            {
+                put(1, "Dark Chocolate");
+            }
+        });
+
+        assertNotEquals(actualBakedGoodsMap.get("Eclair"), null);
+        actualBakedGoodsMap.remove("Eclair");
+        assertEquals(actualBakedGoodsMap.get("Eclair"), null);
+    }
+
+    @Test
+    public void whenFlattenMap_thenRemovesNesting() {
+
+        Map<String, String> flattenedBakedGoodsMap = mUtil.flattenMap(actualBakedGoodsMap);
+        assertThat(flattenedBakedGoodsMap, IsMapContaining.hasKey("Donut.2"));
+
+        Map<String, String> flattenedEmployeeAddressMap = mUtil.flattenMap(actualEmployeeAddressMap);
+        assertThat(flattenedEmployeeAddressMap, IsMapContaining.hasKey("200.Bag End"));
+    }
+
+    @Before
+    public void buildMaps() {
+
+        batterList = Arrays.asList("Mulberry", "Cranberry", "Blackberry", "Mixed fruit", "Orange");
+
+        actualBakedGoodsMap.put("Cake", mUtil.buildInnerMap(batterList));
+
+        batterList = new ArrayList<>();
+        batterList = Arrays.asList("Candy", "Dark Chocolate", "Chocolate", "Jam filled", "Pineapple");
+
+        actualBakedGoodsMap.put("Donut", mUtil.buildInnerMap(batterList));
+
+        listEmployee.add(new Employee(1, new Address(124, "Timbuktoo"), "Thorin Oakenshield"));
+        listEmployee.add(new Employee(2, new Address(100, "Misty Lanes"), "Balin"));
+        listEmployee.add(new Employee(3, new Address(156, "Brambles Lane"), "Bofur"));
+        listEmployee.add(new Employee(4, new Address(200, "Bag End"), "Bilbo Baggins"));
+        listEmployee.add(new Employee(5, new Address(23, "Rivendell"), "Elrond"));
+
+        actualEmployeeAddressMap = mUtil.createNestedMapfromStream(listEmployee);
+
+        actualEmployeeMap = mUtil.createNestedObjectMap(listEmployee);
+
+    }
+
+    private Map<Integer, Map<Integer, Address>> setupAddressObjectMap() {
+
+        Map<Integer, Map<Integer, Address>> expectedMap = new HashMap<>();
+
+        expectedMap.put(1, new HashMap<Integer, Address>() {
+            {
+                put(124, new Address(124, "Timbuktoo"));
+            }
+        });
+        expectedMap.put(2, new HashMap<Integer, Address>() {
+            {
+                put(100, new Address(100, "Misty Lanes"));
+            }
+        });
+        expectedMap.put(3, new HashMap<Integer, Address>() {
+            {
+                put(156, new Address(156, "Brambles Lane"));
+            }
+        });
+        expectedMap.put(4, new HashMap<Integer, Address>() {
+            {
+                put(200, new Address(200, "Bag End"));
+            }
+        });
+        expectedMap.put(5, new HashMap<Integer, Address>() {
+            {
+                put(23, new Address(23, "Rivendell"));
+            }
+        });
+        return expectedMap;
+    }
+
+}
@@ -20,17 +20,6 @@
            <artifactId>commons-collections4</artifactId>
            <version>${commons-collections4.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

-    <properties>
-        <commons-collections4.version>4.1</commons-collections4.version>
-        <assertj.version>3.6.1</assertj.version>
-    </properties>
-
 </project>
@@ -12,7 +12,6 @@
        <groupId>com.baeldung.core-java-modules</groupId>
        <artifactId>core-java-modules</artifactId>
        <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../</relativePath>
    </parent>

    <dependencies>
@@ -50,7 +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>

@@ -12,4 +12,5 @@ This module contains articles about Java collections
 - [Defining a Char Stack in Java](https://www.baeldung.com/java-char-stack)
 - [Guide to the Java Queue Interface](https://www.baeldung.com/java-queue)
 - [An Introduction to Synchronized Java Collections](https://www.baeldung.com/java-synchronized-collections)
- [[More -->]](/core-java-modules/core-java-collections-2)
+- [Convert an Array of Primitives to a List](https://www.baeldung.com/java-primitive-array-to-list)
+- More articles: [[next -->]](/core-java-modules/core-java-collections-2)
@@ -15,12 +15,6 @@
    </parent>

    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.openjdk.jmh</groupId>
            <artifactId>jmh-core</artifactId>
@@ -31,10 +25,11 @@
            <artifactId>jmh-generator-annprocess</artifactId>
            <version>${jmh-generator.version}</version>
        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
    </dependencies>

-    <properties>
-        <assertj.version>3.11.1</assertj.version>
-    </properties>
-
 </project>
@@ -1,13 +1,15 @@
-package com.baeldung.collections.iterators;
+package com.baeldung.collections.convertarrayprimitives;

-import java.util.List;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
-import com.google.common.primitives.Ints;
+
 import org.apache.commons.lang3.ArrayUtils;

+import com.google.common.primitives.Ints;
+
 public class ConvertPrimitivesArrayToList {

    public static void failConvert() {
@@ -1,14 +1,11 @@
-package com.baeldung.collections.iterators;
-
-import java.util.List;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.stream.Collectors;
-import com.google.common.primitives.Ints;
-import org.junit.Test;
+package com.baeldung.collections.convertarrayprimitives;

 import static org.junit.Assert.assertEquals;

+import java.util.Arrays;
+
+import org.junit.Test;
+
 public class ConvertPrimitivesArrayToListUnitTest {

    @Test
@@ -15,11 +15,6 @@
    </parent>

    <dependencies>
-        <dependency>
-            <groupId>org.junit.vintage</groupId>
-            <artifactId>junit-vintage-engine</artifactId>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>com.googlecode.thread-weaver</groupId>
            <artifactId>threadweaver</artifactId>
@@ -31,6 +26,12 @@
            <artifactId>tempus-fugit</artifactId>
            <version>${tempus-fugit.version}</version>
            <scope>test</scope>
+            <exclusions>
+                <exclusion>
+                    <groupId>junit</groupId>
+                    <artifactId>junit</artifactId>
+                </exclusion>
+            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.googlecode.multithreadedtc</groupId>
@@ -30,12 +30,6 @@
            <artifactId>jmh-generator-annprocess</artifactId>
            <version>${jmh-generator.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <build>
@@ -48,8 +42,4 @@
        </resources>
    </build>

-    <properties>
-        <assertj.version>3.6.1</assertj.version>
-    </properties>
-
 </project>
@@ -15,12 +15,6 @@
    </parent>

    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>com.jcabi</groupId>
            <artifactId>jcabi-aspects</artifactId>
@@ -94,7 +88,6 @@
    </build>

    <properties>
-        <assertj.version>3.14.0</assertj.version>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <jcabi-aspects.version>0.22.6</jcabi-aspects.version>
@@ -3,17 +3,18 @@ package com.baeldung.abaproblem;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;

+import static com.google.common.util.concurrent.Uninterruptibles.sleepUninterruptibly;
+
 public class Account {

-    private AtomicInteger balance;
-    private AtomicInteger transactionCount;
-    private ThreadLocal<Integer> currentThreadCASFailureCount;
+    private final AtomicInteger balance;
+    private final AtomicInteger transactionCount;
+    private final ThreadLocal<Integer> currentThreadCASFailureCount;

    public Account() {
        this.balance = new AtomicInteger(0);
        this.transactionCount = new AtomicInteger(0);
-        this.currentThreadCASFailureCount = new ThreadLocal<>();
-        this.currentThreadCASFailureCount.set(0);
+        this.currentThreadCASFailureCount = ThreadLocal.withInitial(() -> 0);
    }

    public int getBalance() {
@@ -43,11 +44,7 @@ public class Account {

    private void maybeWait() {
        if ("thread1".equals(Thread.currentThread().getName())) {
-            try {
-                TimeUnit.SECONDS.sleep(2);
-            } catch (InterruptedException e) {
-                Thread.currentThread().interrupt();
-            }
+            sleepUninterruptibly(2, TimeUnit.SECONDS);
        }
    }

@@ -1,8 +1,13 @@
 package com.baeldung.abaproblem;

+import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;

+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -30,45 +35,39 @@ public class AccountUnitTest {
        assertTrue(account.deposit(moneyToDeposit));

        assertEquals(moneyToDeposit, account.getBalance());
+        assertEquals(1, account.getTransactionCount());
    }

    @Test
-    public void withdrawTest() throws InterruptedException {
+    public void withdrawTest() {
        final int defaultBalance = 50;
        final int moneyToWithdraw = 20;

        account.deposit(defaultBalance);

        assertTrue(account.withdraw(moneyToWithdraw));
-
        assertEquals(defaultBalance - moneyToWithdraw, account.getBalance());
    }

    @Test
-    public void abaProblemTest() throws InterruptedException {
+    public void abaProblemTest() throws Exception {
        final int defaultBalance = 50;

        final int amountToWithdrawByThread1 = 20;
        final int amountToWithdrawByThread2 = 10;
        final int amountToDepositByThread2 = 10;

-        assertEquals(0, account.getTransactionCount());
-        assertEquals(0, account.getCurrentThreadCASFailureCount());
        account.deposit(defaultBalance);
-        assertEquals(1, account.getTransactionCount());
-
-        Thread thread1 = new Thread(() -> {

+        Runnable thread1 = () -> {
            // this will take longer due to the name of the thread
            assertTrue(account.withdraw(amountToWithdrawByThread1));

            // thread 1 fails to capture ABA problem
            assertNotEquals(1, account.getCurrentThreadCASFailureCount());
+        };

-        }, "thread1");
-
-        Thread thread2 = new Thread(() -> {
-
+        Runnable thread2 = () -> {
            assertTrue(account.deposit(amountToDepositByThread2));
            assertEquals(defaultBalance + amountToDepositByThread2, account.getBalance());

@@ -79,12 +78,13 @@ public class AccountUnitTest {
            assertEquals(defaultBalance, account.getBalance());

            assertEquals(0, account.getCurrentThreadCASFailureCount());
-        }, "thread2");
+        };

-        thread1.start();
-        thread2.start();
-        thread1.join();
-        thread2.join();
+        Future<?> future1 = getSingleThreadExecutorService("thread1").submit(thread1);
+        Future<?> future2 = getSingleThreadExecutorService("thread2").submit(thread2);
+
+        future1.get();
+        future2.get();

        // compareAndSet operation succeeds for thread 1
        assertEquals(defaultBalance - amountToWithdrawByThread1, account.getBalance());
@@ -95,4 +95,10 @@ public class AccountUnitTest {
        // thread 2 did two modifications as well
        assertEquals(4, account.getTransactionCount());
    }
+
+    private static ExecutorService getSingleThreadExecutorService(String threadName) {
+        return Executors.newSingleThreadExecutor(
+          new ThreadFactoryBuilder().setNameFormat(threadName).build()
+        );
+    }
 }
@@ -35,12 +35,6 @@
            <artifactId>commons-math3</artifactId>
            <version>${commons-math3.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>com.jayway.awaitility</groupId>
            <artifactId>awaitility</artifactId>
@@ -60,13 +54,9 @@
    </build>

    <properties>
-        <!-- util -->
        <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>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
        <avaitility.version>1.7.0</avaitility.version>
    </properties>

@@ -20,12 +20,6 @@
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>com.jayway.awaitility</groupId>
            <artifactId>awaitility</artifactId>
@@ -45,8 +39,6 @@
    </build>

    <properties>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
        <avaitility.version>1.7.0</avaitility.version>
    </properties>

@@ -29,18 +29,10 @@
            <artifactId>jmh-generator-annprocess</artifactId>
            <version>${jmh-generator.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <properties>
        <guava.version>28.2-jre</guava.version>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
    </properties>

 </project>
@@ -14,15 +14,6 @@
        <version>0.0.1-SNAPSHOT</version>
    </parent>

-    <dependencies>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
    <build>
        <finalName>core-java-concurrency-collections</finalName>
        <resources>
@@ -33,9 +24,4 @@
        </resources>
    </build>

-    <properties>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
-    </properties>
-
 </project>
@@ -12,7 +12,6 @@
        <groupId>com.baeldung.core-java-modules</groupId>
        <artifactId>core-java-modules</artifactId>
        <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../</relativePath>
    </parent>

    <dependencies>
@@ -26,16 +25,11 @@
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
+
        <dependency>
            <groupId>com.darwinsys</groupId>
            <artifactId>hirondelle-date4j</artifactId>
-            <version>RELEASE</version>
+            <version>${hirondelle-date4j.version}</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
@@ -63,8 +57,7 @@

    <properties>
        <joda-time.version>2.10</joda-time.version>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
+        <hirondelle-date4j.version>RELEASE</hirondelle-date4j.version>
        <maven.compiler.source>1.9</maven.compiler.source>
        <maven.compiler.target>1.9</maven.compiler.target>
    </properties>
@@ -30,18 +30,11 @@
            <artifactId>hirondelle-date4j</artifactId>
            <version>${hirondelle-date4j.version}</version>
        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <properties>
        <joda-time.version>2.10</joda-time.version>
        <hirondelle-date4j.version>1.5.1</hirondelle-date4j.version>
-        <assertj.version>3.14.0</assertj.version>
    </properties>

 </project>
@@ -31,13 +31,6 @@
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
-        <!-- test scoped -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
    </dependencies>

    <build>
@@ -63,8 +56,6 @@

    <properties>
        <joda-time.version>2.10</joda-time.version>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
        <maven.compiler.source>1.9</maven.compiler.source>
        <maven.compiler.target>1.9</maven.compiler.target>
    </properties>
@@ -12,7 +12,6 @@
        <groupId>com.baeldung.core-java-modules</groupId>
        <artifactId>core-java-modules</artifactId>
        <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../</relativePath>
    </parent>

    <dependencies>
@@ -32,13 +31,6 @@
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
-        <!-- test scoped -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
@@ -47,7 +39,7 @@
        <dependency>
            <groupId>com.darwinsys</groupId>
            <artifactId>hirondelle-date4j</artifactId>
-            <version>RELEASE</version>
+            <version>${hirondelle-date4j.version}</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
@@ -76,8 +68,7 @@
    <properties>
        <commons-validator.version>1.6</commons-validator.version>
        <joda-time.version>2.10.10</joda-time.version>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
+        <hirondelle-date4j.version>RELEASE</hirondelle-date4j.version>
        <maven.compiler.source>1.9</maven.compiler.source>
        <maven.compiler.target>1.9</maven.compiler.target>
    </properties>
@@ -15,24 +15,11 @@
    </parent>

    <dependencies>
-        <!-- test scoped -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj-core.version}</version>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
-            <version>${commons.lang3.version}</version>
+            <version>${commons-lang3.version}</version>
        </dependency>
    </dependencies>

-    <properties>
-        <commons.lang3.version>3.10</commons.lang3.version>
-        <!-- testing -->
-        <assertj-core.version>3.10.0</assertj-core.version>
-    </properties>
-
 </project>
@@ -19,21 +19,13 @@
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
-            <version>1.4.191</version>
-            <scope>test</scope>
-        </dependency>
-        <!-- test scoped -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj-core.version}</version>
+            <version>${h2.version}</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <properties>
-        <!-- testing -->
-        <assertj-core.version>3.10.0</assertj-core.version>
+        <h2.version>1.4.191</h2.version>
    </properties>

 </project>
@@ -4,7 +4,9 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 public class SynchronizedReceiver implements Runnable {
-    private static Logger log = LoggerFactory.getLogger(SynchronizedReceiver.class);
+
+    private static final Logger LOG = LoggerFactory.getLogger(SynchronizedReceiver.class);
+
    private final Data data;
    private String message;
    private boolean illegalMonitorStateExceptionOccurred;
@@ -20,10 +22,10 @@ public class SynchronizedReceiver implements Runnable {
                data.wait();
                this.message = data.receive();
            } catch (InterruptedException e) {
-                log.error("thread was interrupted", e);
+                LOG.error("thread was interrupted", e);
                Thread.currentThread().interrupt();
            } catch (IllegalMonitorStateException e) {
-                log.error("illegal monitor state exception occurred", e);
+                LOG.error("illegal monitor state exception occurred", e);
                illegalMonitorStateExceptionOccurred = true;
            }
        }
@@ -4,7 +4,9 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 public class SynchronizedSender implements Runnable {
-    private static Logger log = LoggerFactory.getLogger(SynchronizedSender.class);
+
+    private static final Logger LOG = LoggerFactory.getLogger(SynchronizedSender.class);
+
    private final Data data;
    private boolean illegalMonitorStateExceptionOccurred;

@@ -22,10 +24,10 @@ public class SynchronizedSender implements Runnable {

                data.notifyAll();
            } catch (InterruptedException e) {
-                log.error("thread was interrupted", e);
+                LOG.error("thread was interrupted", e);
                Thread.currentThread().interrupt();
            } catch (IllegalMonitorStateException e) {
-                log.error("illegal monitor state exception occurred", e);
+                LOG.error("illegal monitor state exception occurred", e);
                illegalMonitorStateExceptionOccurred = true;
            }
        }
@@ -4,7 +4,8 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 public class UnsynchronizedReceiver implements Runnable {
-    private static Logger log = LoggerFactory.getLogger(UnsynchronizedReceiver.class);
+    private static final Logger LOG = LoggerFactory.getLogger(UnsynchronizedReceiver.class);
+
    private final Data data;
    private String message;
    private boolean illegalMonitorStateExceptionOccurred;
@@ -19,10 +20,10 @@ public class UnsynchronizedReceiver implements Runnable {
            data.wait();
            this.message = data.receive();
        } catch (InterruptedException e) {
-            log.error("thread was interrupted", e);
+            LOG.error("thread was interrupted", e);
            Thread.currentThread().interrupt();
        } catch (IllegalMonitorStateException e) {
-            log.error("illegal monitor state exception occurred", e);
+            LOG.error("illegal monitor state exception occurred", e);
            illegalMonitorStateExceptionOccurred = true;
        }
    }
@@ -4,7 +4,8 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 public class UnsynchronizedSender implements Runnable {
-    private static Logger log = LoggerFactory.getLogger(UnsynchronizedSender.class);
+    private static final Logger LOG = LoggerFactory.getLogger(UnsynchronizedSender.class);
+
    private final Data data;
    private boolean illegalMonitorStateExceptionOccurred;

@@ -21,10 +22,10 @@ public class UnsynchronizedSender implements Runnable {

            data.notifyAll();
        } catch (InterruptedException e) {
-            log.error("thread was interrupted", e);
+            LOG.error("thread was interrupted", e);
            Thread.currentThread().interrupt();
        } catch (IllegalMonitorStateException e) {
-            log.error("illegal monitor state exception occurred", e);
+            LOG.error("illegal monitor state exception occurred", e);
            illegalMonitorStateExceptionOccurred = true;
        }
    }
@@ -1,8 +1,11 @@
 package com.baeldung.exceptions.illegalmonitorstate;

-import org.junit.jupiter.api.Test;
+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 static org.junit.jupiter.api.Assertions.*;
+import org.junit.jupiter.api.Test;

 public class IllegalMonitorStateExceptionUnitTest {

@@ -18,10 +21,9 @@ public class IllegalMonitorStateExceptionUnitTest {
        Thread senderThread = new Thread(sender, "sender-thread");
        senderThread.start();

-        senderThread.join(1000);
-        receiverThread.join(1000);
-        
-        Thread.sleep(2000);
+        // we need to wait for the sender and receiver threads to finish
+        senderThread.join(10_000);
+        receiverThread.join(10_000);

        assertEquals("test", receiver.getMessage());
        assertFalse(sender.hasIllegalMonitorStateExceptionOccurred());
@@ -30,22 +30,12 @@
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
-            <version>${commons.lang3.version}</version>
-        </dependency>
-        <!-- test scoped -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj-core.version}</version>
-            <scope>test</scope>
+            <version>${commons-lang3.version}</version>
        </dependency>
    </dependencies>

    <properties>
        <javax.mail.version>1.5.0-b01</javax.mail.version>
-        <commons.lang3.version>3.10</commons.lang3.version>
-        <!-- testing -->
-        <assertj-core.version>3.10.0</assertj-core.version>
    </properties>

 </project>
@@ -14,16 +14,6 @@
        <version>0.0.1-SNAPSHOT</version>
    </parent>

-    <dependencies>
-        <!-- test scoped -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
    <build>
        <finalName>core-java-function</finalName>
        <resources>
@@ -34,9 +24,4 @@
        </resources>
    </build>

-    <properties>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
-    </properties>
-
 </project>
--- a/Show More
+++ b/Show More