Merge remote-tracking branch 'upstream/master' into feature/BAEL-6695-BooleanValidation

algorithms-modules/algorithms-miscellaneous-7/src/main/java/com/baeldung/algorithms/rotatearray/RotateArray.java

@@ -0,0 +1,102 @@
+package com.baeldung.algorithms.rotatearray;
+
+/**
+ *  To speed up the rotation, we narrow k rotations to the remainder of k divided by the array length, or k module the array length.
+ *  Therefore, a large rotation number will be translated into the relative smallest rotation.
+ *  All solutions replace the original array, although they might use an extra array to compute the rotation.
+ */
+public class RotateArray {
+
+    private RotateArray() {
+        throw new IllegalStateException("Rotate array algorithm utility methods class");
+    }
+
+    /**
+     *
+     * @param arr array to apply rotation to
+     * @param k number of rotations
+     */
+    public static void bruteForce(int[] arr, int k) {
+        checkInvalidInput(arr, k);
+
+        k %= arr.length;
+        int temp;
+        int previous;
+        for (int i = 0; i < k; i++) {
+            previous = arr[arr.length - 1];
+            for (int j = 0; j < arr.length; j++) {
+                temp = arr[j];
+                arr[j] = previous;
+                previous = temp;
+            }
+        }
+    }
+
+    /**
+     *
+     * @param arr array to apply rotation to
+     * @param k number of rotations
+     */
+    public static void withExtraArray(int[] arr, int k) {
+        checkInvalidInput(arr, k);
+
+        int[] extraArray = new int[arr.length];
+        for (int i = 0; i < arr.length; i++) {
+            extraArray[(i + k) % arr.length] = arr[i];
+        }
+        System.arraycopy(extraArray, 0, arr, 0, arr.length);
+    }
+
+    /**
+     *
+     * @param arr array to apply rotation to
+     * @param k number of rotations
+     */
+    public static void cyclicReplacement(int[] arr, int k) {
+        checkInvalidInput(arr, k);
+
+        k = k % arr.length;
+        int count = 0;
+        for (int start = 0; count < arr.length; start++) {
+            int current = start;
+            int prev = arr[start];
+            do {
+                int next = (current + k) % arr.length;
+                int temp = arr[next];
+                arr[next] = prev;
+                prev = temp;
+                current = next;
+                count++;
+            } while (start != current);
+        }
+    }
+
+    /**
+     *
+     * @param arr array to apply rotation to
+     * @param k number of rotations
+     */
+    public static void reverse(int[] arr, int k) {
+        checkInvalidInput(arr, k);
+
+        k %= arr.length;
+        reverse(arr, 0, arr.length - 1);
+        reverse(arr, 0, k - 1);
+        reverse(arr, k, arr.length - 1);
+    }
+
+    private static void reverse(int[] nums, int start, int end) {
+        while (start < end) {
+            int temp = nums[start];
+            nums[start] = nums[end];
+            nums[end] = temp;
+            start++;
+            end--;
+        }
+    }
+
+    private static void checkInvalidInput(int[] arr, int rotation) {
+        if (rotation < 1 || arr == null)
+            throw new IllegalArgumentException("Rotation must be greater than zero or array must be not null");
+    }
+}

algorithms-modules/algorithms-miscellaneous-7/src/test/java/com/baeldung/algorithms/rotatearray/RotateArrayUnitTest.java

@@ -0,0 +1,124 @@
+package com.baeldung.algorithms.rotatearray;
+
+import static com.baeldung.algorithms.rotatearray.RotateArray.bruteForce;
+import static com.baeldung.algorithms.rotatearray.RotateArray.cyclicReplacement;
+import static com.baeldung.algorithms.rotatearray.RotateArray.reverse;
+import static com.baeldung.algorithms.rotatearray.RotateArray.withExtraArray;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class RotateArrayUnitTest {
+
+    private final int[] arr = { 1, 2, 3, 4, 5, 6 };
+    private final int rotationLtArrayLength = 1;
+    private final int rotationGtArrayLength = arr.length + 2;
+    private final int[] ltArrayLengthRotation = { 6, 1, 2, 3, 4, 5 };
+    private final int[] gtArrayLengthRotation = { 5, 6, 1, 2, 3, 4 };
+
+    @Test
+    void givenInputArray_whenNoRotationOrEmptyArray_thenThrowIllegalArgumentException() {
+        final int noRotation = 0;
+        final int someRotation = arr.length - 1;
+
+        assertThrows(IllegalArgumentException.class, () -> bruteForce(arr, noRotation));
+        assertThrows(IllegalArgumentException.class, () -> withExtraArray(arr, noRotation));
+        assertThrows(IllegalArgumentException.class, () -> cyclicReplacement(arr, noRotation));
+        assertThrows(IllegalArgumentException.class, () -> reverse(arr, noRotation));
+
+        assertThrows(IllegalArgumentException.class, () -> bruteForce(null, someRotation));
+        assertThrows(IllegalArgumentException.class, () -> withExtraArray(null, someRotation));
+        assertThrows(IllegalArgumentException.class, () -> cyclicReplacement(null, someRotation));
+        assertThrows(IllegalArgumentException.class, () -> reverse(null, someRotation));
+    }
+
+    @Test
+    void givenInputArray_whenUseBruteForceRotationLtArrayLength_thenRotateArrayOk() {
+
+        bruteForce(arr, rotationLtArrayLength);
+        assertArrayEquals(ltArrayLengthRotation, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseBruteForceRotationGtArrayLength_thenRotateArrayOk() {
+
+        bruteForce(arr, rotationGtArrayLength);
+        assertArrayEquals(gtArrayLengthRotation, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseBruteForceRotationEqArrayLength_thenDoNothing() {
+        int[] expected = arr.clone();
+
+        bruteForce(arr, arr.length);
+        assertArrayEquals(expected, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseExtraArrayRotationLtArrayLength_thenRotateArrayOk() {
+
+        withExtraArray(arr, rotationLtArrayLength);
+        assertArrayEquals(ltArrayLengthRotation, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseExtraArrayRotationGtArrayLength_thenRotateArrayOk() {
+
+        withExtraArray(arr, rotationGtArrayLength);
+        assertArrayEquals(gtArrayLengthRotation, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseExtraArrayWithRotationEqArrayLength_thenDoNothing() {
+        int[] clone = arr.clone();
+
+        withExtraArray(arr, arr.length);
+        assertArrayEquals(clone, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseCyclicReplacementRotationLtArrayLength_thenRotateArrayOk() {
+
+        cyclicReplacement(arr, rotationLtArrayLength);
+        assertArrayEquals(ltArrayLengthRotation, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseCyclicReplacementRotationGtArrayLength_thenRotateArrayOk() {
+
+        cyclicReplacement(arr, rotationGtArrayLength);
+        assertArrayEquals(gtArrayLengthRotation, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseCyclicReplacementRotationEqArrayLength_thenDoNothing() {
+        int[] clone = arr.clone();
+
+        cyclicReplacement(arr, arr.length);
+        assertArrayEquals(clone, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseReverseRotationLtArrayLength_thenRotateArrayOk() {
+
+        reverse(arr, rotationLtArrayLength);
+        assertArrayEquals(ltArrayLengthRotation, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseReverseRotationGtArrayLength_thenRotateArrayOk() {
+
+        reverse(arr, rotationGtArrayLength);
+        assertArrayEquals(gtArrayLengthRotation, arr);
+    }
+
+    @Test
+    void givenInputArray_whenUseReverseRotationEqArrayLength_thenDoNothing() {
+
+        int[] clone = arr.clone();
+
+        reverse(arr, arr.length);
+        assertArrayEquals(clone, arr);
+    }
+}

aws-modules/aws-dynamodb/.gitignore

@@ -0,0 +1,2 @@
+/target/
+.idea/

aws-modules/aws-dynamodb/README.md

@@ -0,0 +1,7 @@
+## AWS DYNAMODB
+
+This module contains articles about AWS DynamoDB
+
+### Relevant articles
+- [Integration Testing with a Local DynamoDB Instance](https://www.baeldung.com/dynamodb-local-integration-tests)
+

aws-modules/aws-dynamodb/pom.xml

@@ -0,0 +1,87 @@
+<?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>aws-dynamodb</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>aws-dynamodb</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>aws-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.amazonaws</groupId>
+            <artifactId>aws-java-sdk</artifactId>
+            <version>${aws-java-sdk.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.amazonaws</groupId>
+            <artifactId>DynamoDBLocal</artifactId>
+            <version>${dynamodblocal.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons-io.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>${gson.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>${maven-shade-plugin.version}</version>
+                <configuration>
+                    <createDependencyReducedPom>false</createDependencyReducedPom>
+                </configuration>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-dependency-plugin</artifactId>
+                <version>${maven-plugins-version}</version>
+                <executions>
+                    <execution>
+                        <id>copy</id>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>copy-dependencies</goal>
+                        </goals>
+                        <configuration>
+                            <includeScope></includeScope>
+                            <includeTypes>so,dll,dylib</includeTypes>
+                            <outputDirectory>native-libs</outputDirectory>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <gson.version>2.8.0</gson.version>
+        <dynamodblocal.version>1.21.1</dynamodblocal.version>
+        <maven-plugins-version>3.1.1</maven-plugins-version>
+    </properties>
+
+</project>

aws-modules/aws-dynamodb/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

aws-modules/aws-dynamodb/src/test/java/com/baeldung/dynamodb/ProductInfoRepositoryIntegrationTest.java

@@ -49,10 +49,10 @@ public class ProductInfoRepositoryIntegrationTest {
     @BeforeClass
     public static void setupClass() {
         Properties testProperties = loadFromFileInClasspath("test.properties")
-                .filter(properties -> !isEmpty(properties.getProperty(AWS_ACCESSKEY)))
+            .filter(properties -> !isEmpty(properties.getProperty(AWS_ACCESSKEY)))
-                .filter(properties -> !isEmpty(properties.getProperty(AWS_SECRETKEY)))
+            .filter(properties -> !isEmpty(properties.getProperty(AWS_SECRETKEY)))
-                .filter(properties -> !isEmpty(properties.getProperty(DYNAMODB_ENDPOINT)))
+            .filter(properties -> !isEmpty(properties.getProperty(DYNAMODB_ENDPOINT)))
-                .orElseThrow(() -> new RuntimeException("Unable to get all of the required test property values"));
+            .orElseThrow(() -> new RuntimeException("Unable to get all of the required test property values"));
 
         String amazonAWSAccessKey = testProperties.getProperty(AWS_ACCESSKEY);
         String amazonAWSSecretKey = testProperties.getProperty(AWS_SECRETKEY);

aws-modules/aws-miscellaneous/pom.xml

@@ -16,31 +16,9 @@
 
     <dependencies>
         <dependency>
-            <groupId>com.amazonaws</groupId>
+            <groupId>software.amazon.awssdk</groupId>
-            <artifactId>aws-java-sdk</artifactId>
+            <artifactId>aws-sdk-java</artifactId>
-            <version>${aws-java-sdk.version}</version>
+            <version>${aws-java-sdk-v2.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>com.amazonaws</groupId>
-            <artifactId>aws-lambda-java-core</artifactId>
-            <version>${aws-lambda-java-core.version}</version>
-            <exclusions>
-                <exclusion>
-                    <artifactId>commons-logging</artifactId>
-                    <groupId>commons-logging</groupId>
-                </exclusion>
-            </exclusions>
-        </dependency>
-        <dependency>
-            <groupId>com.amazonaws</groupId>
-            <artifactId>aws-lambda-java-events</artifactId>
-            <version>${aws-lambda-java-events.version}</version>
-            <exclusions>
-                <exclusion>
-                    <artifactId>commons-logging</artifactId>
-                    <groupId>commons-logging</groupId>
-                </exclusion>
-            </exclusions>
         </dependency>
         <dependency>
             <groupId>commons-io</groupId>
@@ -52,12 +30,6 @@
             <artifactId>gson</artifactId>
             <version>${gson.version}</version>
         </dependency>
-        <dependency>
-            <groupId>com.amazonaws</groupId>
-            <artifactId>DynamoDBLocal</artifactId>
-            <version>${dynamodblocal.version}</version>
-            <scope>test</scope>
-        </dependency>
     </dependencies>
 
     <build>
@@ -101,8 +73,6 @@
     </build>
 
     <properties>
-        <aws-lambda-java-events.version>1.3.0</aws-lambda-java-events.version>
-        <aws-lambda-java-core.version>1.1.0</aws-lambda-java-core.version>
         <gson.version>2.8.0</gson.version>
         <dynamodblocal.version>1.21.1</dynamodblocal.version>
         <commons-codec-version>1.10.L001</commons-codec-version>

aws-modules/aws-miscellaneous/src/main/java/com/baeldung/ec2/EC2Application.java

@@ -2,136 +2,148 @@ package com.baeldung.ec2;
 
 import java.util.Arrays;
 
-import com.amazonaws.auth.AWSCredentials;
+import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
-import com.amazonaws.auth.AWSStaticCredentialsProvider;
+import software.amazon.awssdk.regions.Region;
-import com.amazonaws.auth.BasicAWSCredentials;
+import software.amazon.awssdk.services.ec2.Ec2Client;
-import com.amazonaws.regions.Regions;
+import software.amazon.awssdk.services.ec2.model.AuthorizeSecurityGroupIngressRequest;
-import com.amazonaws.services.ec2.AmazonEC2;
+import software.amazon.awssdk.services.ec2.model.CreateKeyPairRequest;
-import com.amazonaws.services.ec2.AmazonEC2ClientBuilder;
+import software.amazon.awssdk.services.ec2.model.CreateKeyPairResponse;
-import com.amazonaws.services.ec2.model.AuthorizeSecurityGroupIngressRequest;
+import software.amazon.awssdk.services.ec2.model.CreateSecurityGroupRequest;
-import com.amazonaws.services.ec2.model.CreateKeyPairRequest;
+import software.amazon.awssdk.services.ec2.model.DescribeInstancesRequest;
-import com.amazonaws.services.ec2.model.CreateKeyPairResult;
+import software.amazon.awssdk.services.ec2.model.DescribeInstancesResponse;
-import com.amazonaws.services.ec2.model.CreateSecurityGroupRequest;
+import software.amazon.awssdk.services.ec2.model.DescribeKeyPairsRequest;
-import com.amazonaws.services.ec2.model.DescribeInstancesRequest;
+import software.amazon.awssdk.services.ec2.model.DescribeKeyPairsResponse;
-import com.amazonaws.services.ec2.model.DescribeInstancesResult;
+import software.amazon.awssdk.services.ec2.model.IpPermission;
-import com.amazonaws.services.ec2.model.DescribeKeyPairsRequest;
+import software.amazon.awssdk.services.ec2.model.IpRange;
-import com.amazonaws.services.ec2.model.DescribeKeyPairsResult;
+import software.amazon.awssdk.services.ec2.model.MonitorInstancesRequest;
-import com.amazonaws.services.ec2.model.IpPermission;
+import software.amazon.awssdk.services.ec2.model.RebootInstancesRequest;
-import com.amazonaws.services.ec2.model.IpRange;
+import software.amazon.awssdk.services.ec2.model.RunInstancesRequest;
-import com.amazonaws.services.ec2.model.MonitorInstancesRequest;
+import software.amazon.awssdk.services.ec2.model.RunInstancesResponse;
-import com.amazonaws.services.ec2.model.RebootInstancesRequest;
+import software.amazon.awssdk.services.ec2.model.StartInstancesRequest;
-import com.amazonaws.services.ec2.model.RunInstancesRequest;
+import software.amazon.awssdk.services.ec2.model.StartInstancesResponse;
-import com.amazonaws.services.ec2.model.StartInstancesRequest;
+import software.amazon.awssdk.services.ec2.model.StopInstancesRequest;
-import com.amazonaws.services.ec2.model.StopInstancesRequest;
+import software.amazon.awssdk.services.ec2.model.UnmonitorInstancesRequest;
-import com.amazonaws.services.ec2.model.UnmonitorInstancesRequest;
 
 public class EC2Application {
 
-    private static final AWSCredentials credentials;
-
-    static {
-        // put your accesskey and secretkey here
-        credentials = new BasicAWSCredentials(
-            "<AWS accesskey>", 
-            "<AWS secretkey>"
-        );
-    }
-
     public static void main(String[] args) {
        
         // Set up the client
-        AmazonEC2 ec2Client = AmazonEC2ClientBuilder.standard()
+        Ec2Client ec2Client = Ec2Client.builder()
-            .withCredentials(new AWSStaticCredentialsProvider(credentials))
+            .credentialsProvider(ProfileCredentialsProvider.create("default"))
-            .withRegion(Regions.US_EAST_1)
+            .region(Region.US_EAST_1)
             .build();
 
         // Create a security group
-        CreateSecurityGroupRequest createSecurityGroupRequest = new CreateSecurityGroupRequest().withGroupName("BaeldungSecurityGroup")
+        CreateSecurityGroupRequest createSecurityGroupRequest = CreateSecurityGroupRequest.builder()
-            .withDescription("Baeldung Security Group");
+            .groupName("BaeldungSecurityGroup")
+            .description("Baeldung Security Group")
+            .build();
+
         ec2Client.createSecurityGroup(createSecurityGroupRequest);
 
         // Allow HTTP and SSH traffic
-        IpRange ipRange1 = new IpRange().withCidrIp("0.0.0.0/0");
+        IpRange ipRange1 = IpRange.builder()
+            .cidrIp("0.0.0.0/0")
+            .build();
 
-        IpPermission ipPermission1 = new IpPermission().withIpv4Ranges(Arrays.asList(new IpRange[] { ipRange1 }))
+        IpPermission ipPermission1 = IpPermission.builder()
-            .withIpProtocol("tcp")
+            .ipRanges(Arrays.asList(ipRange1))
-            .withFromPort(80)
+            .ipProtocol("tcp")
-            .withToPort(80);
+            .fromPort(80)
+            .toPort(80)
+            .build();
 
-        IpPermission ipPermission2 = new IpPermission().withIpv4Ranges(Arrays.asList(new IpRange[] { ipRange1 }))
+        IpPermission ipPermission2 = IpPermission.builder()
-            .withIpProtocol("tcp")
+            .ipRanges(Arrays.asList(ipRange1))
-            .withFromPort(22)
+            .ipProtocol("tcp")
-            .withToPort(22);
+            .fromPort(22)
+            .toPort(22)
+            .build();
 
-        AuthorizeSecurityGroupIngressRequest authorizeSecurityGroupIngressRequest = new AuthorizeSecurityGroupIngressRequest()
+        AuthorizeSecurityGroupIngressRequest authorizeSecurityGroupIngressRequest = AuthorizeSecurityGroupIngressRequest
-            .withGroupName("BaeldungSecurityGroup")
+            .builder()
-            .withIpPermissions(ipPermission1, ipPermission2);
+            .groupName("BaeldungSecurityGroup")
+            .ipPermissions(ipPermission1, ipPermission2)
+            .build();
 
         ec2Client.authorizeSecurityGroupIngress(authorizeSecurityGroupIngressRequest);
 
         // Create KeyPair
-        CreateKeyPairRequest createKeyPairRequest = new CreateKeyPairRequest()
+        CreateKeyPairRequest createKeyPairRequest = CreateKeyPairRequest.builder()
-            .withKeyName("baeldung-key-pair");
+            .keyName("baeldung-key-pair")
-        CreateKeyPairResult createKeyPairResult = ec2Client.createKeyPair(createKeyPairRequest);
+            .build();
-        String privateKey = createKeyPairResult
+
-            .getKeyPair()
+        CreateKeyPairResponse createKeyPairResponse = ec2Client.createKeyPair(createKeyPairRequest);
-            .getKeyMaterial(); // make sure you keep it, the private key, Amazon doesn't store the private key
+        String privateKey = createKeyPairResponse.keyMaterial();
+        // make sure you keep it, the private key, Amazon doesn't store the private key
 
         // See what key-pairs you've got
-        DescribeKeyPairsRequest describeKeyPairsRequest = new DescribeKeyPairsRequest();
+        DescribeKeyPairsRequest describeKeyPairsRequest = DescribeKeyPairsRequest.builder()
-        DescribeKeyPairsResult describeKeyPairsResult = ec2Client.describeKeyPairs(describeKeyPairsRequest);
+            .build();
+        DescribeKeyPairsResponse describeKeyPairsResponse = ec2Client.describeKeyPairs(describeKeyPairsRequest);
 
         // Launch an Amazon Instance
-        RunInstancesRequest runInstancesRequest = new RunInstancesRequest().withImageId("ami-97785bed") // https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AMIs.html | https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/usingsharedamis-finding.html
+        RunInstancesRequest runInstancesRequest = RunInstancesRequest.builder()
-            .withInstanceType("t2.micro") // https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html
+            .imageId("ami-97785bed")
-            .withMinCount(1)
+            .instanceType("t2.micro") // https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html
-            .withMaxCount(1)
+            .minCount(1)
-            .withKeyName("baeldung-key-pair") // optional - if not present, can't connect to instance
+            .maxCount(1)
-            .withSecurityGroups("BaeldungSecurityGroup");
+            .keyName("baeldung-key-pair") // optional - if not present, can't connect to instance
+            .securityGroups("BaeldungSecurityGroup")
+            .build();
 
-        String yourInstanceId = ec2Client.runInstances(runInstancesRequest).getReservation().getInstances().get(0).getInstanceId();
+        RunInstancesResponse runInstancesResponse = ec2Client.runInstances(runInstancesRequest);
+        String yourInstanceId = runInstancesResponse.instances().get(0).instanceId();
 
         // Start an Instance
-        StartInstancesRequest startInstancesRequest = new StartInstancesRequest()
+        StartInstancesRequest startInstancesRequest = StartInstancesRequest.builder()
-            .withInstanceIds(yourInstanceId);
+            .instanceIds(yourInstanceId)
+            .build();
+
+        StartInstancesResponse startInstancesResponse = ec2Client.startInstances(startInstancesRequest);
 
-        ec2Client.startInstances(startInstancesRequest);
 
         // Monitor Instances
-        MonitorInstancesRequest monitorInstancesRequest = new MonitorInstancesRequest()
+        MonitorInstancesRequest monitorInstancesRequest = MonitorInstancesRequest.builder()
-            .withInstanceIds(yourInstanceId);
+            .instanceIds(yourInstanceId)
+            .build();
+
 
         ec2Client.monitorInstances(monitorInstancesRequest);
 
-        UnmonitorInstancesRequest unmonitorInstancesRequest = new UnmonitorInstancesRequest()
+        UnmonitorInstancesRequest unmonitorInstancesRequest = UnmonitorInstancesRequest.builder()
-            .withInstanceIds(yourInstanceId);
+            .instanceIds(yourInstanceId)
+            .build();
 
         ec2Client.unmonitorInstances(unmonitorInstancesRequest);
 
         // Reboot an Instance
-
+        RebootInstancesRequest rebootInstancesRequest = RebootInstancesRequest.builder()
-        RebootInstancesRequest rebootInstancesRequest = new RebootInstancesRequest()
+            .instanceIds(yourInstanceId)
-            .withInstanceIds(yourInstanceId);
+            .build();
 
         ec2Client.rebootInstances(rebootInstancesRequest);
 
         // Stop an Instance
-        StopInstancesRequest stopInstancesRequest = new StopInstancesRequest()
+        StopInstancesRequest stopInstancesRequest = StopInstancesRequest.builder()
-            .withInstanceIds(yourInstanceId);
+            .instanceIds(yourInstanceId)
+            .build();
+
 
         ec2Client.stopInstances(stopInstancesRequest)
-            .getStoppingInstances()
+            .stoppingInstances()
             .get(0)
-            .getPreviousState()
+            .previousState()
-            .getName();
+            .name();
 
         // Describe an Instance
-        DescribeInstancesRequest describeInstancesRequest = new DescribeInstancesRequest();
+        DescribeInstancesRequest describeInstancesRequest = DescribeInstancesRequest.builder().build();
-        DescribeInstancesResult response = ec2Client.describeInstances(describeInstancesRequest);
+        DescribeInstancesResponse response = ec2Client.describeInstances(describeInstancesRequest);
-        System.out.println(response.getReservations()
+        System.out.println(response.reservations()
             .get(0)
-            .getInstances()
+            .instances()
             .get(0)
-            .getKernelId());
+            .kernelId());
     }
 }

aws-modules/aws-miscellaneous/src/main/java/com/baeldung/rds/AWSRDSService.java

@@ -1,13 +1,5 @@
 package com.baeldung.rds;
 
-import com.amazonaws.auth.AWSCredentialsProvider;
-import com.amazonaws.auth.AWSStaticCredentialsProvider;
-import com.amazonaws.auth.BasicAWSCredentials;
-import com.amazonaws.regions.Regions;
-import com.amazonaws.services.rds.AmazonRDS;
-import com.amazonaws.services.rds.AmazonRDSClientBuilder;
-import com.amazonaws.services.rds.model.*;
-
 import java.io.IOException;
 import java.io.InputStream;
 import java.sql.*;
@@ -16,12 +8,22 @@ import java.util.Properties;
 import java.util.UUID;
 import java.util.logging.Logger;
 
+import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
+import software.amazon.awssdk.regions.Region;
+import software.amazon.awssdk.services.rds.RdsClient;
+import software.amazon.awssdk.services.rds.model.CreateDbInstanceRequest;
+import software.amazon.awssdk.services.rds.model.CreateDbInstanceResponse;
+import software.amazon.awssdk.services.rds.model.DBInstance;
+import software.amazon.awssdk.services.rds.model.DeleteDbInstanceRequest;
+import software.amazon.awssdk.services.rds.model.DeleteDbInstanceResponse;
+import software.amazon.awssdk.services.rds.model.DescribeDbInstancesResponse;
+import software.amazon.awssdk.services.rds.model.Endpoint;
+
 public class AWSRDSService {
 
 
     final static Logger logger = Logger.getLogger(AWSRDSService.class.getName());
-    private AWSCredentialsProvider credentials;
+    private RdsClient rdsClient;
-    private AmazonRDS amazonRDS;
     private String db_username;
     private String db_password;
     private String db_database;
@@ -34,22 +36,17 @@ public class AWSRDSService {
     * **/
     public AWSRDSService() throws IOException {
         //Init RDS client with credentials and region.
-        credentials = new
-                AWSStaticCredentialsProvider(new
-                BasicAWSCredentials("<ACCESS_KEY>",
-                "<SECRET_KEY>"));
-        amazonRDS = AmazonRDSClientBuilder.standard().withCredentials(credentials)
-                .withRegion(Regions.AP_SOUTHEAST_2).build();
         Properties prop = new Properties();
         InputStream input = AWSRDSService.class.getClassLoader().getResourceAsStream("db.properties");
         prop.load(input);
         db_username = prop.getProperty("db_username");
         db_password = prop.getProperty("db_password");
         db_database = prop.getProperty("db_database");
-    }
 
-    public AWSRDSService(AmazonRDS amazonRDS){
+        rdsClient = RdsClient.builder()
-        this.amazonRDS = amazonRDS;
+            .region(Region.AP_SOUTHEAST_2)
+            .credentialsProvider(ProfileCredentialsProvider.create("default"))
+            .build();
     }
 
     /**
@@ -60,29 +57,29 @@ public class AWSRDSService {
     public String launchInstance() {
 
         String identifier = "";
-        CreateDBInstanceRequest request = new CreateDBInstanceRequest();
+        CreateDbInstanceRequest instanceRequest = CreateDbInstanceRequest.builder()
-        // RDS instance name
+            .dbInstanceIdentifier("Sydney")
-        request.setDBInstanceIdentifier("Sydney");
+            .engine("postgres")
-        request.setEngine("postgres");
+            .multiAZ(false)
-        request.setMultiAZ(false);
+            .masterUsername(db_username)
-        request.setMasterUsername(db_username);
+            .masterUserPassword(db_password)
-        request.setMasterUserPassword(db_password);
+            .dbName(db_database)
-        request.setDBName(db_database);
+            .storageType("gp2")
-        request.setStorageType("gp2");
+            .allocatedStorage(10)
-        request.setAllocatedStorage(10);
+            .build();
 
-        DBInstance instance = amazonRDS.createDBInstance(request);
+        CreateDbInstanceResponse createDbInstanceResponse = rdsClient.createDBInstance(instanceRequest);
 
         // Information about the new RDS instance
-        identifier = instance.getDBInstanceIdentifier();
+        identifier = createDbInstanceResponse.dbInstance().dbInstanceIdentifier();
-        String status = instance.getDBInstanceStatus();
+        String status = createDbInstanceResponse.dbInstance().dbInstanceStatus();
-        Endpoint endpoint = instance.getEndpoint();
+        Endpoint endpoint = createDbInstanceResponse.dbInstance().endpoint();
-        String endpoint_url = "Endpoint URL not available yet.";
+        String endpointUrl = "Endpoint URL not available yet.";
         if (endpoint != null) {
-            endpoint_url = endpoint.toString();
+            endpointUrl = endpoint.toString();
         }
         logger.info(identifier + "\t" + status);
-        logger.info(endpoint_url);
+        logger.info(endpointUrl);
 
         return identifier;
 
@@ -90,44 +87,44 @@ public class AWSRDSService {
 
     // Describe DB instances
     public void listInstances() {
-        DescribeDBInstancesResult result = amazonRDS.describeDBInstances();
+        DescribeDbInstancesResponse response = rdsClient.describeDBInstances();
-        List<DBInstance> instances = result.getDBInstances();
+        List<DBInstance> instances = response.dbInstances();
         for (DBInstance instance : instances) {
             // Information about each RDS instance
-            String identifier = instance.getDBInstanceIdentifier();
+            String identifier = instance.dbInstanceIdentifier();
-            String engine = instance.getEngine();
+            String engine = instance.engine();
-            String status = instance.getDBInstanceStatus();
+            String status = instance.dbInstanceStatus();
-            Endpoint endpoint = instance.getEndpoint();
+            Endpoint endpoint = instance.endpoint();
-            String endpoint_url = "Endpoint URL not available yet.";
+            String endpointUrl = "Endpoint URL not available yet.";
             if (endpoint != null) {
-                endpoint_url = endpoint.toString();
+                endpointUrl = endpoint.toString();
             }
             logger.info(identifier + "\t" + engine + "\t" + status);
-            logger.info("\t" + endpoint_url);
+            logger.info("\t" + endpointUrl);
         }
-
     }
 
     //Delete RDS instance
     public void terminateInstance(String identifier) {
 
-        DeleteDBInstanceRequest request = new DeleteDBInstanceRequest();
+        DeleteDbInstanceRequest request = DeleteDbInstanceRequest.builder()
-        request.setDBInstanceIdentifier(identifier);
+            .dbInstanceIdentifier(identifier)
-        request.setSkipFinalSnapshot(true);
+            .skipFinalSnapshot(true)
+            .build();
 
         // Delete the RDS instance
-        DBInstance instance = amazonRDS.deleteDBInstance(request);
+        DeleteDbInstanceResponse response = rdsClient.deleteDBInstance(request);
 
         // Information about the RDS instance being deleted
-        String status = instance.getDBInstanceStatus();
+        String status = response.dbInstance().dbInstanceStatus();
-        Endpoint endpoint = instance.getEndpoint();
+        Endpoint endpoint = response.dbInstance().endpoint();
-        String endpoint_url = "Endpoint URL not available yet.";
+        String endpointUrl = "Endpoint URL not available yet.";
         if (endpoint != null) {
-            endpoint_url = endpoint.toString();
+            endpointUrl = endpoint.toString();
         }
 
         logger.info(identifier + "\t" + status);
-        logger.info(endpoint_url);
+        logger.info(endpointUrl);
 
     }
 

aws-modules/aws-miscellaneous/src/main/java/com/baeldung/sqs/SQSApplication.java

@@ -5,140 +5,190 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
-import com.amazonaws.auth.AWSCredentials;
+import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
-import com.amazonaws.auth.AWSStaticCredentialsProvider;
+import software.amazon.awssdk.regions.Region;
-import com.amazonaws.auth.BasicAWSCredentials;
+import software.amazon.awssdk.services.sqs.SqsClient;
-import com.amazonaws.regions.Regions;
+import software.amazon.awssdk.services.sqs.model.CreateQueueRequest;
-import com.amazonaws.services.sqs.AmazonSQSClientBuilder;
+import software.amazon.awssdk.services.sqs.model.DeleteMessageRequest;
-import com.amazonaws.services.sqs.model.CreateQueueRequest;
+import software.amazon.awssdk.services.sqs.model.GetQueueAttributesRequest;
-import com.amazonaws.services.sqs.model.DeleteMessageRequest;
+import software.amazon.awssdk.services.sqs.model.GetQueueAttributesResponse;
-import com.amazonaws.services.sqs.model.GetQueueAttributesRequest;
+import software.amazon.awssdk.services.sqs.model.GetQueueUrlRequest;
-import com.amazonaws.services.sqs.model.GetQueueAttributesResult;
+import software.amazon.awssdk.services.sqs.model.GetQueueUrlResponse;
-import com.amazonaws.services.sqs.model.MessageAttributeValue;
+import software.amazon.awssdk.services.sqs.model.Message;
-import com.amazonaws.services.sqs.model.ReceiveMessageRequest;
+import software.amazon.awssdk.services.sqs.model.MessageAttributeValue;
-import com.amazonaws.services.sqs.model.SendMessageBatchRequest;
+import software.amazon.awssdk.services.sqs.model.QueueAttributeName;
-import com.amazonaws.services.sqs.model.SendMessageRequest;
+import software.amazon.awssdk.services.sqs.model.ReceiveMessageRequest;
-import com.amazonaws.services.sqs.model.SetQueueAttributesRequest;
+import software.amazon.awssdk.services.sqs.model.SendMessageBatchRequest;
-import com.amazonaws.services.sqs.model.SendMessageBatchRequestEntry;
+import software.amazon.awssdk.services.sqs.model.SendMessageBatchRequestEntry;
-import com.amazonaws.services.sqs.model.Message;
+import software.amazon.awssdk.services.sqs.model.SendMessageRequest;
-import com.amazonaws.services.sqs.AmazonSQS;
+import software.amazon.awssdk.services.sqs.model.SetQueueAttributesRequest;
 
 public class SQSApplication {
 
-    private static final AWSCredentials credentials;
+    private static final String STANDARD_QUEUE_NAME = "baeldung-queue";
-
+    private static final String FIFO_QUEUE_NAME = "baeldung-queue.fifo";
-    static {
+    private static final String DEAD_LETTER_QUEUE_NAME = "baeldung-dead-letter-queue";
-        // put your accesskey and secretkey here
-        credentials = new BasicAWSCredentials(
-            "<AWS accesskey>", 
-            "<AWS secretkey>"
-        );
-    }
 
     public static void main(String[] args) {
 
         // Set up the client
-        AmazonSQS sqs = AmazonSQSClientBuilder.standard()
+        SqsClient sqsClient = SqsClient.builder()
-            .withCredentials(new AWSStaticCredentialsProvider(credentials))
+            .region(Region.US_EAST_1)
-            .withRegion(Regions.US_EAST_1)
+            .credentialsProvider(ProfileCredentialsProvider.create())
             .build();
 
         // Create a standard queue
+        CreateQueueRequest createStandardQueueRequest = CreateQueueRequest.builder()
+            .queueName(STANDARD_QUEUE_NAME)
+            .build();
 
-        CreateQueueRequest createStandardQueueRequest = new CreateQueueRequest("baeldung-queue");
+        sqsClient.createQueue(createStandardQueueRequest);
-        String standardQueueUrl = sqs.createQueue(createStandardQueueRequest)
+
-            .getQueueUrl();
+        System.out.println("\nGet queue url");
+
+        GetQueueUrlResponse getQueueUrlResponse = sqsClient.getQueueUrl(GetQueueUrlRequest.builder()
+            .queueName(STANDARD_QUEUE_NAME)
+            .build());
+        String standardQueueUrl = getQueueUrlResponse.queueUrl();
 
         System.out.println(standardQueueUrl);
 
         // Create a fifo queue
+        Map<QueueAttributeName, String> queueAttributes = new HashMap<>();
+        queueAttributes.put(QueueAttributeName.FIFO_QUEUE, "true");
+        queueAttributes.put(QueueAttributeName.CONTENT_BASED_DEDUPLICATION, "true");
 
-        Map<String, String> queueAttributes = new HashMap<String, String>();
+        CreateQueueRequest createFifoQueueRequest = CreateQueueRequest.builder()
-        queueAttributes.put("FifoQueue", "true");
+            .queueName(FIFO_QUEUE_NAME)
-        queueAttributes.put("ContentBasedDeduplication", "true");
+            .attributes(queueAttributes)
+            .build();
 
-        CreateQueueRequest createFifoQueueRequest = new CreateQueueRequest("baeldung-queue.fifo").withAttributes(queueAttributes);
+        sqsClient.createQueue(createFifoQueueRequest);
-        String fifoQueueUrl = sqs.createQueue(createFifoQueueRequest)
+
-            .getQueueUrl();
+        GetQueueUrlResponse getFifoQueueUrlResponse = sqsClient.getQueueUrl(GetQueueUrlRequest.builder()
+            .queueName(FIFO_QUEUE_NAME)
+            .build());
+
+        String fifoQueueUrl = getFifoQueueUrlResponse.queueUrl();
 
         System.out.println(fifoQueueUrl);
 
         // Set up a dead letter queue
+        CreateQueueRequest createDeadLetterQueueRequest = CreateQueueRequest.builder()
+            .queueName(DEAD_LETTER_QUEUE_NAME)
+            .build();
 
-        String deadLetterQueueUrl = sqs.createQueue("baeldung-dead-letter-queue")
+        String deadLetterQueueUrl = sqsClient.createQueue(createDeadLetterQueueRequest)
-            .getQueueUrl();
+            .queueUrl();
 
-        GetQueueAttributesResult deadLetterQueueAttributes = sqs.getQueueAttributes(new GetQueueAttributesRequest(deadLetterQueueUrl).withAttributeNames("QueueArn"));
+        GetQueueAttributesRequest getQueueAttributesRequest = GetQueueAttributesRequest.builder()
+            .queueUrl(deadLetterQueueUrl)
+            .attributeNames(QueueAttributeName.QUEUE_ARN)
+            .build();
 
-        String deadLetterQueueARN = deadLetterQueueAttributes.getAttributes()
+        GetQueueAttributesResponse deadLetterQueueAttributes = sqsClient.getQueueAttributes(getQueueAttributesRequest);
+
+        String deadLetterQueueARN = deadLetterQueueAttributes.attributes()
             .get("QueueArn");
 
-        SetQueueAttributesRequest queueAttributesRequest = new SetQueueAttributesRequest().withQueueUrl(standardQueueUrl)
+        Map<QueueAttributeName, String> attributes = new HashMap<>();
-            .addAttributesEntry("RedrivePolicy", "{\"maxReceiveCount\":\"2\", " + "\"deadLetterTargetArn\":\"" + deadLetterQueueARN + "\"}");
+        attributes.put(QueueAttributeName.REDRIVE_POLICY, "{\"maxReceiveCount\":\"5\", \"deadLetterTargetArn\":\"" + deadLetterQueueARN + "\"}");
 
-        sqs.setQueueAttributes(queueAttributesRequest);
+        SetQueueAttributesRequest queueAttributesRequest = SetQueueAttributesRequest.builder()
+            .queueUrl(standardQueueUrl)
+            .attributes(attributes)
+            .build();
+
+        sqsClient.setQueueAttributes(queueAttributesRequest);
 
         // Send a message to a standard queue
 
         Map<String, MessageAttributeValue> messageAttributes = new HashMap<>();
+        MessageAttributeValue messageAttributeValue = MessageAttributeValue.builder()
+            .stringValue("This is an attribute")
+            .dataType("String")
+            .build();
 
-        messageAttributes.put("AttributeOne", new MessageAttributeValue().withStringValue("This is an attribute")
+        messageAttributes.put("AttributeOne", messageAttributeValue);
-            .withDataType("String"));
 
-        SendMessageRequest sendMessageStandardQueue = new SendMessageRequest().withQueueUrl(standardQueueUrl)
+        SendMessageRequest sendMessageStandardQueue = SendMessageRequest.builder()
-            .withMessageBody("A simple message.")
+            .queueUrl(standardQueueUrl)
-            .withDelaySeconds(30) // Message will arrive in the queue after 30 seconds. We can use this only in standard queues
+            .messageBody("A simple message.")
-            .withMessageAttributes(messageAttributes);
+            .delaySeconds(30) // Message will arrive in the queue after 30 seconds. We can use this only in standard queues
+            .messageAttributes(messageAttributes)
+            .build();
 
-        sqs.sendMessage(sendMessageStandardQueue);
+        sqsClient.sendMessage(sendMessageStandardQueue);
 
         // Send a message to a fifo queue
 
-        SendMessageRequest sendMessageFifoQueue = new SendMessageRequest().withQueueUrl(fifoQueueUrl)
+        SendMessageRequest sendMessageFifoQueue = SendMessageRequest.builder()
-            .withMessageBody("FIFO Queue")
+            .queueUrl(fifoQueueUrl)
-            .withMessageGroupId("baeldung-group-1")
+            .messageBody("FIFO Queue")
-            .withMessageAttributes(messageAttributes);
+            .messageGroupId("baeldung-group-1")
+            .messageAttributes(messageAttributes)
+            .build();
 
-        sqs.sendMessage(sendMessageFifoQueue);
+        sqsClient.sendMessage(sendMessageFifoQueue);
 
         // Send multiple messages
 
         List<SendMessageBatchRequestEntry> messageEntries = new ArrayList<>();
-        messageEntries.add(new SendMessageBatchRequestEntry().withId("id-1")
+        SendMessageBatchRequestEntry messageBatchRequestEntry1 = SendMessageBatchRequestEntry.builder()
-            .withMessageBody("batch-1")
+            .id("id-1")
-            .withMessageGroupId("baeldung-group-1"));
+            .messageBody("batch-1")
-        messageEntries.add(new SendMessageBatchRequestEntry().withId("id-2")
+            .messageGroupId("baeldung-group-1")
-            .withMessageBody("batch-2")
+            .build();
-            .withMessageGroupId("baeldung-group-1"));
 
-        SendMessageBatchRequest sendMessageBatchRequest = new SendMessageBatchRequest(fifoQueueUrl, messageEntries);
+        SendMessageBatchRequestEntry messageBatchRequestEntry2 = SendMessageBatchRequestEntry.builder()
-        sqs.sendMessageBatch(sendMessageBatchRequest);
+            .id("id-2")
+            .messageBody("batch-2")
+            .messageGroupId("baeldung-group-1")
+            .build();
+
+        messageEntries.add(messageBatchRequestEntry1);
+        messageEntries.add(messageBatchRequestEntry2);
+
+        SendMessageBatchRequest sendMessageBatchRequest = SendMessageBatchRequest.builder()
+            .queueUrl(fifoQueueUrl)
+            .entries(messageEntries)
+            .build();
+
+        sqsClient.sendMessageBatch(sendMessageBatchRequest);
 
         // Read a message from a queue
 
-        ReceiveMessageRequest receiveMessageRequest = new ReceiveMessageRequest(fifoQueueUrl).withWaitTimeSeconds(10) // Long polling;
+        ReceiveMessageRequest receiveMessageRequest = ReceiveMessageRequest.builder()
-            .withMaxNumberOfMessages(1); // Max is 10
+            .waitTimeSeconds(10)
+            .maxNumberOfMessages(10)
+            .build();
 
-        List<Message> sqsMessages = sqs.receiveMessage(receiveMessageRequest)
+        List<Message> sqsMessages = sqsClient.receiveMessage(receiveMessageRequest)
-            .getMessages();
+            .messages();
 
         sqsMessages.get(0)
-            .getAttributes();
+            .attributes();
         sqsMessages.get(0)
-            .getBody();
+            .body();
 
         // Delete a message from a queue
+        DeleteMessageRequest deleteMessageRequest = DeleteMessageRequest.builder()
+            .queueUrl(fifoQueueUrl)
+            .receiptHandle(sqsMessages.get(0)
+                .receiptHandle())
+            .build();
 
-        sqs.deleteMessage(new DeleteMessageRequest().withQueueUrl(fifoQueueUrl)
+        sqsClient.deleteMessage(deleteMessageRequest);
-            .withReceiptHandle(sqsMessages.get(0)
-                .getReceiptHandle()));
 
         // Monitoring
-        GetQueueAttributesRequest getQueueAttributesRequest = new GetQueueAttributesRequest(standardQueueUrl).withAttributeNames("All");
+        GetQueueAttributesRequest getQueueAttributesRequestForMonitoring = GetQueueAttributesRequest.builder()
-        GetQueueAttributesResult getQueueAttributesResult = sqs.getQueueAttributes(getQueueAttributesRequest);
+            .queueUrl(standardQueueUrl)
-        System.out.println(String.format("The number of messages on the queue: %s", getQueueAttributesResult.getAttributes()
+            .build();
+
+        GetQueueAttributesResponse attributesResponse = sqsClient.getQueueAttributes(getQueueAttributesRequestForMonitoring);
+        System.out.println(String.format("The number of messages on the queue: %s", attributesResponse.attributes()
             .get("ApproximateNumberOfMessages")));
-        System.out.println(String.format("The number of messages in flight: %s", getQueueAttributesResult.getAttributes()
+        System.out.println(String.format("The number of messages in flight: %s", attributesResponse.attributes()
             .get("ApproximateNumberOfMessagesNotVisible")));
 
     }

aws-modules/pom.xml

@@ -5,6 +5,14 @@
     <modelVersion>4.0.0</modelVersion>
     <artifactId>aws-modules</artifactId>
     <name>aws-modules</name>
+    <dependencies>
+        <dependency>
+            <groupId>com.amazonaws</groupId>
+            <artifactId>aws-java-sdk-dynamodb</artifactId>
+            <version>1.12.523</version>
+            <scope>compile</scope>
+        </dependency>
+    </dependencies>
     <packaging>pom</packaging>
 
     <parent>
@@ -15,6 +23,7 @@
 
     <modules>
         <module>aws-app-sync</module>
+        <module>aws-dynamodb</module>
         <module>aws-lambda-modules</module>
         <module>aws-miscellaneous</module>
         <module>aws-reactive</module>
@@ -24,6 +33,7 @@
 
     <properties>
         <aws-java-sdk.version>1.12.331</aws-java-sdk.version>
+        <aws-java-sdk-v2.version>2.20.147</aws-java-sdk-v2.version>
         <maven-shade-plugin.version>3.0.0</maven-shade-plugin.version>
     </properties>
 

core-java-modules/core-java-11-2/README.md

@@ -5,7 +5,6 @@ This module contains articles about Java 11 core features
 ### Relevant articles
 - [Guide To Java 8 Optional](https://www.baeldung.com/java-optional)
 - [Guide to Java Reflection](http://www.baeldung.com/java-reflection)
-- [Guide to Java 8’s Collectors](https://www.baeldung.com/java-8-collectors)
 - [New Features in Java 11](https://www.baeldung.com/java-11-new-features)
 - [Getting the Java Version at Runtime](https://www.baeldung.com/get-java-version-runtime)
 - [Invoking a SOAP Web Service in Java](https://www.baeldung.com/java-soap-web-service)

core-java-modules/core-java-16/README.md

@@ -4,5 +4,4 @@
 - [Guide to mapMulti in Stream API](https://www.baeldung.com/java-mapmulti)
 - [Collecting Stream Elements into a List in Java](https://www.baeldung.com/java-stream-to-list-collecting)
 - [New Features in Java 16](https://www.baeldung.com/java-16-new-features)
-- [Guide to Java 8 groupingBy Collector](https://www.baeldung.com/java-groupingby-collector)
 - [Value-Based Classes in Java](https://www.baeldung.com/java-value-based-classes)

core-java-modules/core-java-16/src/main/java/com/baeldung/value_based_class/Point.java

@@ -30,6 +30,11 @@ public final class Point {
         return new Point(x, y, z);
     }
 
+    @Override
+    public String toString() {
+        return "Point{" + "x=" + x + ", y=" + y + ", z=" + z + '}';
+    }
+
     @Override
     public boolean equals(Object other) {
         if (other == null || getClass() != other.getClass())

core-java-modules/core-java-16/src/test/java/com/baeldung/value_based_class/ValueBasedClassUnitTest.java

@@ -1,14 +1,17 @@
 package com.baeldung.value_based_class;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import org.junit.Assert;
 import org.junit.Test;
 
 public class ValueBasedClassUnitTest {
     @Test
     public void givenAutoboxedAndPrimitive_whenCompared_thenReturnEquals() {
-        int primitive_a = 125;
+        List<Integer> list = new ArrayList<>();
-        Integer obj_a = 125; // this is autoboxed
+        list.add(1); // this is autoboxed
-        Assert.assertSame(primitive_a, obj_a);
+        Assert.assertEquals(list.get(0), Integer.valueOf(1));
     }
 
     @Test

core-java-modules/core-java-17/src/test/java/com/baeldung/recordproperties/ReadRecordPropertiesByReflectionUnitTest.java

@@ -0,0 +1,89 @@
+package com.baeldung.recordproperties;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.RecordComponent;
+import java.util.ArrayList;
+
+import org.junit.jupiter.api.Test;
+
+record Player(String name, int age, Long score) {
+}
+
+public class ReadRecordPropertiesByReflectionUnitTest {
+    private static final Player ERIC = new Player("Eric", 28, 4242L);
+
+    @Test
+    void whenUsingRecordComponent_thenGetExpectedResult() {
+        var fields = new ArrayList<Field>();
+        RecordComponent[] components = Player.class.getRecordComponents();
+        for (var comp : components) {
+            try {
+                Field field = ERIC.getClass()
+                  .getDeclaredField(comp.getName());
+                field.setAccessible(true);
+                fields.add(field);
+            } catch (NoSuchFieldException e) {
+                // for simplicity, error handling is skipped
+            }
+        }
+
+        assertEquals(3, fields.size());
+
+        var nameField = fields.get(0);
+        var ageField = fields.get(1);
+        var scoreField = fields.get(2);
+        try {
+            assertEquals("name", nameField.getName());
+            assertEquals(String.class, nameField.getType());
+            assertEquals("Eric", nameField.get(ERIC));
+
+            assertEquals("age", ageField.getName());
+            assertEquals(int.class, ageField.getType());
+            assertEquals(28, ageField.get(ERIC));
+
+            assertEquals("score", scoreField.getName());
+            assertEquals(Long.class, scoreField.getType());
+            assertEquals(4242L, scoreField.get(ERIC));
+        } catch (IllegalAccessException exception) {
+            // for simplicity, error handling is skipped
+        }
+
+    }
+
+    @Test
+    void whenUsingClassGetDeclaredField_thenGetExpectedResult() {
+        // record has no public fields
+        assertEquals(0, Player.class.getFields().length);
+
+        var fields = new ArrayList<Field>();
+        for (var field : Player.class.getDeclaredFields()) {
+            field.setAccessible(true);
+            fields.add(field);
+        }
+
+        assertEquals(3, fields.size());
+        var nameField = fields.get(0);
+        var ageField = fields.get(1);
+        var scoreField = fields.get(2);
+
+        try {
+            assertEquals("name", nameField.getName());
+            assertEquals(String.class, nameField.getType());
+            assertEquals("Eric", nameField.get(ERIC));
+
+            assertEquals("age", ageField.getName());
+            assertEquals(int.class, ageField.getType());
+            assertEquals(28, ageField.get(ERIC));
+
+            assertEquals("score", scoreField.getName());
+            assertEquals(Long.class, scoreField.getType());
+            assertEquals(4242L, scoreField.get(ERIC));
+        } catch (IllegalAccessException ex) {
+            // for simplicity, error handling is skipped
+        }
+
+    }
+
+}

core-java-modules/core-java-18/pom.xml

@@ -0,0 +1,55 @@
+<?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-18</artifactId>
+    <name>core-java-18</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <release>${maven.compiler.release}</release>
+                    <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>${surefire.plugin.version}</version>
+                <configuration>
+                    <forkCount>1</forkCount>
+                </configuration>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.apache.maven.surefire</groupId>
+                        <artifactId>surefire-api</artifactId>
+                        <version>${surefire.plugin.version}</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <maven.compiler.source.version>18</maven.compiler.source.version>
+        <maven.compiler.target.version>18</maven.compiler.target.version>
+        <maven.compiler.release>18</maven.compiler.release>
+        <surefire.plugin.version>3.0.0-M5</surefire.plugin.version>
+    </properties>
+
+</project>

core-java-modules/core-java-18/src/main/java/com/baeldung/finalization_closeable_cleaner/FinalizationExamples.java

@@ -0,0 +1,27 @@
+package com.baeldung.finalization_closeable_cleaner;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+
+public class FinalizationExamples {
+    FileInputStream fis = null;
+
+    public void readFileOperationWithFinalization() throws IOException {
+        try {
+            fis = new FileInputStream("input.txt");
+            // perform operation on the file
+            System.out.println(fis.readAllBytes().length);
+
+        } finally {
+            if (fis != null)
+                fis.close();
+        }
+    }
+
+    public void readFileOperationWithTryWith() throws IOException {
+        try (FileInputStream fis = new FileInputStream("input.txt")) {
+            // perform operations
+            System.out.println(fis.readAllBytes().length);
+        }
+    }
+}

core-java-modules/core-java-18/src/main/java/com/baeldung/finalization_closeable_cleaner/MyCleanerResourceClass.java

@@ -0,0 +1,48 @@
+package com.baeldung.finalization_closeable_cleaner;
+
+import java.lang.ref.Cleaner;
+
+public class MyCleanerResourceClass implements AutoCloseable {
+    private static Resource resource;
+
+    private static final Cleaner cleaner = Cleaner.create();
+    private final Cleaner.Cleanable cleanable;
+
+    public MyCleanerResourceClass() {
+        resource = new Resource();
+        this.cleanable = cleaner.register(this, new CleaningState());
+    }
+
+    public void useResource() {
+        // using the resource here
+        resource.use();
+    }
+
+    @Override
+    public void close() {
+        // perform actions to close all underlying resources
+        this.cleanable.clean();
+    }
+
+    static class CleaningState implements Runnable {
+        CleaningState() {
+            // constructor
+        }
+
+        @Override
+        public void run() {
+            // some cleanup action
+            System.out.println("Cleanup done");
+        }
+    }
+
+    static class Resource {
+        void use() {
+            System.out.println("Using the resource");
+        }
+
+        void close() {
+            System.out.println("Cleanup done");
+        }
+    }
+}

core-java-modules/core-java-18/src/main/java/com/baeldung/finalization_closeable_cleaner/MyCloseableResourceClass.java

@@ -0,0 +1,25 @@
+package com.baeldung.finalization_closeable_cleaner;
+
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+
+public class MyCloseableResourceClass implements AutoCloseable {
+
+    private final FileInputStream fis;
+
+    public MyCloseableResourceClass() throws FileNotFoundException {
+        this.fis = new FileInputStream("src/main/resources/file.txt");
+
+    }
+
+    public int getByteLength() throws IOException {
+        System.out.println("Some operation");
+        return this.fis.readAllBytes().length;
+    }
+    @Override
+    public void close() throws IOException {
+        System.out.println("Finalized object");
+        this.fis.close();
+    }
+}

core-java-modules/core-java-18/src/main/java/com/baeldung/finalization_closeable_cleaner/MyFinalizableResourceClass.java

@@ -0,0 +1,24 @@
+package com.baeldung.finalization_closeable_cleaner;
+
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+
+public class MyFinalizableResourceClass {
+    private FileInputStream fis;
+
+    public MyFinalizableResourceClass() throws FileNotFoundException {
+        this.fis = new FileInputStream("src/main/resources/file.txt");
+    }
+
+    public int getByteLength() throws IOException {
+        System.out.println("Some operation");
+        return this.fis.readAllBytes().length;
+    }
+
+    @Override
+    protected void finalize() throws Throwable {
+        System.out.println("Finalized object");
+        this.fis.close();
+    }
+}

core-java-modules/core-java-18/src/main/resources/file.txt

@@ -0,0 +1 @@
+This is a test file.

core-java-modules/core-java-18/src/test/java/com/baeldung/finalization_closeable_cleaner/FinalizationCloseableCleanerUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.finalization_closeable_cleaner;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+import java.io.IOException;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class FinalizationCloseableCleanerUnitTest {
+
+    @Test
+    public void givenMyFinalizationResource_whenUsingFinalize_thenShouldClean() {
+        assertDoesNotThrow(() -> {
+            MyFinalizableResourceClass mfr = new MyFinalizableResourceClass();
+            mfr.getByteLength();
+        });
+    }
+    @Test
+    public void givenMyCleanerResource_whenUsingCleanerAPI_thenShouldClean() {
+        assertDoesNotThrow(() -> {
+            try (MyCleanerResourceClass myCleanerResourceClass = new MyCleanerResourceClass()) {
+                myCleanerResourceClass.useResource();
+            }
+        });
+    }
+
+    @Test
+    public void givenCloseableResource_whenUsingTryWith_thenShouldClose() throws IOException {
+        int length = 0;
+        try (MyCloseableResourceClass mcr = new MyCloseableResourceClass()) {
+            length = mcr.getByteLength();
+        }
+        Assert.assertEquals(20, length);
+    }
+}

core-java-modules/core-java-arrays-convert/README.md

@@ -10,3 +10,4 @@ This module contains articles about arrays conversion in Java
 - [Convert Java Array to Iterable](https://www.baeldung.com/java-array-convert-to-iterable)
 - [Converting an int[] to HashSet in Java](https://www.baeldung.com/java-converting-int-array-to-hashset)
 - [Convert an ArrayList of String to a String Array in Java](https://www.baeldung.com/java-convert-string-arraylist-array)
+- [Convert Char Array to Int Array in Java](https://www.baeldung.com/java-convert-char-int-array)

core-java-modules/core-java-arrays-convert/src/main/java/com/baeldung/array/conversions/CharArrayToIntArrayUtils.java

@@ -0,0 +1,67 @@
+package com.baeldung.array.conversions;
+
+import java.util.Arrays;
+
+public class CharArrayToIntArrayUtils {
+
+    static int[] usingGetNumericValueMethod(char[] chars) {
+        if (chars == null) {
+            return null;
+        }
+
+        int[] ints = new int[chars.length];
+        for (int i = 0; i < chars.length; i++) {
+            ints[i] = Character.getNumericValue(chars[i]);
+        }
+
+        return ints;
+    }
+
+    static int[] usingDigitMethod(char[] chars) {
+        if (chars == null) {
+            return null;
+        }
+
+        int[] ints = new int[chars.length];
+        for (int i = 0; i < chars.length; i++) {
+            ints[i] = Character.digit(chars[i], 10);
+        }
+
+        return ints;
+    }
+
+    static int[] usingStreamApiMethod(char[] chars) {
+        if (chars == null) {
+            return null;
+        }
+
+        return new String(chars).chars()
+          .map(c -> c - 48)
+          .toArray();
+    }
+
+    static int[] usingParseIntMethod(char[] chars) {
+        if (chars == null) {
+            return null;
+        }
+
+        int[] ints = new int[chars.length];
+        for (int i = 0; i < chars.length; i++) {
+            ints[i] = Integer.parseInt(String.valueOf(chars[i]));
+        }
+
+        return ints;
+    }
+
+    static int[] usingArraysSetAllMethod(char[] chars) {
+        if (chars == null) {
+            return null;
+        }
+
+        int[] ints = new int[chars.length];
+        Arrays.setAll(ints, i -> Character.getNumericValue(chars[i]));
+
+        return ints;
+    }
+
+}

core-java-modules/core-java-arrays-convert/src/test/java/com/baeldung/array/conversions/CharArrayToIntArrayUtilsUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.array.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+class CharArrayToIntArrayUtilsUnitTest {
+
+    @Test
+    void givenCharArray_whenUsingGetNumericValueMethod_shouldGetIntArray() {
+        int[] expected = { 2, 3, 4, 5 };
+        char[] chars = { '2', '3', '4', '5' };
+        int[] result = CharArrayToIntArrayUtils.usingGetNumericValueMethod(chars);
+
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void givenCharArray_whenUsingDigitMethod_shouldGetIntArray() {
+        int[] expected = { 1, 2, 3, 6 };
+        char[] chars = { '1', '2', '3', '6' };
+        int[] result = CharArrayToIntArrayUtils.usingDigitMethod(chars);
+
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void givenCharArray_whenUsingStreamApi_shouldGetIntArray() {
+        int[] expected = { 9, 8, 7, 6 };
+        char[] chars = { '9', '8', '7', '6' };
+        int[] result = CharArrayToIntArrayUtils.usingStreamApiMethod(chars);
+
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void givenCharArray_whenUsingParseIntMethod_shouldGetIntArray() {
+        int[] expected = { 9, 8, 7, 6 };
+        char[] chars = { '9', '8', '7', '6' };
+        int[] result = CharArrayToIntArrayUtils.usingParseIntMethod(chars);
+
+        assertArrayEquals(expected, result);
+    }
+
+    @Test
+    void givenCharArray_whenUsingArraysSetAllMethod_shouldGetIntArray() {
+        int[] expected = { 4, 9, 2, 3 };
+        char[] chars = { '4', '9', '2', '3' };
+        int[] result = CharArrayToIntArrayUtils.usingArraysSetAllMethod(chars);
+
+        assertArrayEquals(expected, result);
+    }
+
+}

core-java-modules/core-java-httpclient/src/main/java/com/baeldung/httpclient/HttpClientPost.java

@@ -123,6 +123,7 @@ public class HttpClientPost {
 
         HttpRequest request = HttpRequest.newBuilder()
           .uri(URI.create(serviceUrl))
+          .header("Content-Type", "application/x-www-form-urlencoded")
           .POST(HttpRequest.BodyPublishers.ofString(getFormDataAsString(formData)))
           .build();
 

core-java-modules/core-java-io-5/src/test/java/com/baeldung/rmlinebreaks/RemoveLinebreaksUnitTest.java

@@ -0,0 +1,72 @@
+package com.baeldung.rmlinebreaks;
+
+import org.junit.jupiter.api.Test;
+
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+public class RemoveLinebreaksUnitTest {
+
+    private Path file1Path() throws Exception {
+        return Paths.get(this.getClass().getClassLoader().getResource("multiple-line-1.txt").toURI());
+    }
+
+    private Path file2Path() throws Exception {
+        return Paths.get(this.getClass().getClassLoader().getResource("multiple-line-2.txt").toURI());
+    }
+
+    @Test
+    void whenRemovingLineSeparatorFromFile1_thenGetTheExpectedResult() throws Exception {
+        String content = Files.readString(file1Path(), StandardCharsets.UTF_8);
+
+        String result = content.replace(System.getProperty("line.separator"), "");
+        assertEquals("A, B, C, D, E, F", result);
+    }
+
+    @Test
+    void whenRemovingLineSeparatorFromFile2_thenNotGetTheExpectedResult() throws Exception {
+        String content = Files.readString(file2Path(), StandardCharsets.UTF_8);
+
+        String result = content.replace(System.getProperty("line.separator"), "");
+        assertNotEquals("A, B, C, D, E, F", result); // <-- NOT equals assertion!
+    }
+
+    @Test
+    void whenRemovingAllLinebreaks_thenGetTheExpectedResult() throws Exception {
+        String content1 = Files.readString(file1Path(), StandardCharsets.UTF_8);
+
+        // file contains CRLF
+        String content2 = Files.readString(file2Path(), StandardCharsets.UTF_8);
+
+        String result1 = content1.replace("\r", "").replace("\n", "");
+        String result2 = content2.replace("\r", "").replace("\n", "");
+
+        assertEquals("A, B, C, D, E, F", result1);
+        assertEquals("A, B, C, D, E, F", result2);
+
+        String resultReplaceAll = content2.replaceAll("[\\n\\r]", "");
+        assertEquals("A, B, C, D, E, F", resultReplaceAll);
+
+    }
+
+    @Test
+    void whenUsingReadAllLinesAndJoin_thenGetExpectedResult() throws Exception {
+        List<String> lines1 = Files.readAllLines(file1Path(), StandardCharsets.UTF_8);
+
+        // file contains CRLF
+        List<String> lines2 = Files.readAllLines(file2Path(), StandardCharsets.UTF_8);
+
+        String result1 = String.join("", lines1);
+        String result2 = String.join("", lines2);
+
+        assertEquals("A, B, C, D, E, F", result1);
+        assertEquals("A, B, C, D, E, F", result2);
+    }
+
+}

core-java-modules/core-java-io-5/src/test/resources/multiple-line-1.txt

@@ -0,0 +1,6 @@
+A,
+ B,
+ C,
+ D,
+ E,
+ F

core-java-modules/core-java-io-5/src/test/resources/multiple-line-2.txt

@@ -0,0 +1,4 @@
+A,
 B,
+ C,
+ D,
 E,
+ F

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/encapsulation/Book.java

@@ -0,0 +1,7 @@
+package com.baeldung.encapsulation;
+
+public class Book {
+    public String author;
+    public int isbn;
+
+}

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/encapsulation/BookDetails.java

@@ -0,0 +1,8 @@
+package com.baeldung.encapsulation;
+
+public class BookDetails {
+
+    public String bookDetails(Book book) {
+        return "author name: " + book.author + " ISBN: " + book.isbn;
+    }
+}

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/encapsulation/BookEncapsulation.java

@@ -0,0 +1,17 @@
+package com.baeldung.encapsulation;
+
+public class BookEncapsulation {
+    public String author;
+    public int isbn;
+    public int id = 1;
+
+    public BookEncapsulation(String author, int isbn) {
+        this.author = author;
+        this.isbn = isbn;
+    }
+
+    public String getBookDetails() {
+        return "author id: " + id + " author name: " + author + " ISBN: " + isbn;
+    }
+
+}

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/encapsulation/BookInformationHiding.java

@@ -0,0 +1,36 @@
+package com.baeldung.encapsulation;
+
+public class BookInformationHiding {
+    private String author;
+    private int isbn;
+    private int id = 1;
+
+    public BookInformationHiding(String author, int isbn) {
+        setAuthor(author);
+        setIsbn(isbn);
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public void setAuthor(String author) {
+        this.author = author;
+    }
+
+    public int getIsbn() {
+        return isbn;
+    }
+
+    public void setIsbn(int isbn) {
+        if (isbn < 0) {
+            throw new IllegalArgumentException("ISBN can't be negative");
+        }
+        this.isbn = isbn;
+    }
+
+    public String getBookDetails() {
+        return "author id: " + id + " author name: " + author + " ISBN: " + isbn;
+    }
+
+}

core-java-modules/core-java-lang-oop-others/src/test/java/com/baeldung/encapsulation/EncapsulationAndInformationHidingUnitTest.java

@@ -0,0 +1,35 @@
+package com.baeldung.encapsulation;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class EncapsulationAndInformationHidingUnitTest {
+
+    @Test
+    public void givenUnencapsulatedClass_whenImplementationClassIsSeparate_thenReturnResult() {
+        Book myBook = new Book();
+        myBook.author = "J.K Rowlings";
+        myBook.isbn = 67890;
+        BookDetails details = new BookDetails();
+        String result = details.bookDetails(myBook);
+        assertEquals("author name: " + myBook.author + " ISBN: " + myBook.isbn, result);
+
+    }
+
+    @Test
+    public void givenEncapsulatedClass_whenDataIsNotHidden_thenReturnResult() {
+        BookEncapsulation myBook = new BookEncapsulation("J.K Rowlings", 67890);
+        String result = myBook.getBookDetails();
+        assertEquals("author id: " + 1 + " author name: " + myBook.author + " ISBN: " + myBook.isbn, result);
+    }
+
+    @Test
+    public void givenEncapsulatedClass_whenDataIsHidden_thenReturnResult() {
+        BookInformationHiding myBook = new BookInformationHiding("J.K Rowlings", 67890);
+        String result = myBook.getBookDetails();
+        assertEquals("author id: " + 1 + " author name: " + myBook.getAuthor() + " ISBN: " + myBook.getIsbn(), result);
+    }
+
+}

core-java-modules/core-java-networking/src/test/java/com/baeldung/networking/url/UrlUnitTest.java

@@ -2,10 +2,15 @@ package com.baeldung.networking.url;
 
 import static java.util.stream.Collectors.toList;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 
+import java.io.IOException;
 import java.net.MalformedURLException;
+import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.Map;
 
 import org.apache.http.client.utils.URIBuilder;
@@ -149,4 +154,24 @@ public class UrlUnitTest {
         assertEquals("http://baeldung.com:9090/articles?topic=java&version=8", url.toString());
     }
 
+    @Test
+    public void givenURI_whenConvertingToURL_thenCorrect() throws IOException, URISyntaxException {
+        String aURIString = "http://courses.baeldung.com";
+        URI uri = new URI(aURIString);
+        URL url = uri.toURL();
+        assertNotNull(url);
+        assertEquals(aURIString, url.toString());
+    }
+
+    @Test
+    public void givenPath_whenConvertingToURIAndThenURL_thenCorrect() throws IOException, URISyntaxException {
+        String finalPath = "file:/D:/baeldung/java-url";
+        Path path = Paths.get("/baeldung/java-url");
+        URI uri = path.toUri();
+        URL url = uri.toURL();
+        assertNotNull(url);
+        // Adapt the finalPath value to match your own path
+        // assertEquals(finalPath, url.toString());
+    }
+
 }

core-java-modules/core-java-numbers-3/src/test/java/com/baeldung/integerToBinary/IntegerToBinaryUnitTest.java

@@ -1,6 +1,8 @@
 package com.baeldung.integerToBinary;
 
+import org.apache.commons.lang3.StringUtils;
 import org.junit.Test;
+
 import static org.junit.Assert.assertEquals;
 
 public class IntegerToBinaryUnitTest {
@@ -24,4 +26,18 @@ public class IntegerToBinaryUnitTest {
         String binaryString = Integer.toString(n, 2);
         assertEquals("111", binaryString);
     }
-}
+
+    @Test
+    public void givenAnInteger_whenFormatAndReplaceCalled_thenZeroPaddedBinaryString() {
+        int n = 7;
+        String binaryString = String.format("%8s", Integer.toBinaryString(n)).replace(" ", "0");
+        assertEquals("00000111", binaryString);
+    }
+
+    @Test
+    public void givenAnInteger_whenUsingApacheStringUtils_thenZeroPaddedBinaryString() {
+        int n = 7;
+        String binaryString = StringUtils.leftPad(Integer.toBinaryString(n), 8, "0");
+        assertEquals("00000111", binaryString);
+    }
+}

core-java-modules/core-java-numbers-6/README.md

@@ -5,4 +5,5 @@
 - [Does Java Read Integers in Little Endian or Big Endian?](https://www.baeldung.com/java-integers-little-big-endian)
 - [How to Split an Integer Number Into Digits in Java](https://www.baeldung.com/java-integer-individual-digits)
 - [Java Double vs. BigDecimal](https://www.baeldung.com/java-double-vs-bigdecimal)
+- [Finding the Square Root of a BigInteger in Java](https://www.baeldung.com/java-find-square-root-biginteger)
 - More articles: [[<-- prev]](../core-java-numbers-5)

core-java-modules/core-java-numbers-6/src/test/java/com/baeldung/javadoublevsbigdecimal/BigDecimalConversionUnitTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.javadoublevsbigdecimal;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+import org.junit.jupiter.api.Test;
+
+public class BigDecimalConversionUnitTest {
+
+    @Test
+    void whenConvertingDoubleToBigDecimal_thenConversionIsCorrect() {
+        double doubleValue = 123.456;
+        BigDecimal bigDecimalValue = BigDecimal.valueOf(doubleValue);
+        BigDecimal expected = new BigDecimal("123.456").setScale(3, RoundingMode.HALF_UP);
+        assertEquals(expected, bigDecimalValue.setScale(3, RoundingMode.HALF_UP));
+    }
+
+    @Test
+    void givenDecimalPlacesGreaterThan15_whenConvertingBigDecimalToDouble_thenPrecisionIsLost() {
+        BigDecimal bigDecimalValue = new BigDecimal("789.1234567890123456");
+        double doubleValue = bigDecimalValue.doubleValue();
+        BigDecimal convertedBackToBigDecimal = BigDecimal.valueOf(doubleValue);
+        assertNotEquals(bigDecimalValue, convertedBackToBigDecimal);
+    }
+}

core-java-modules/core-java-numbers-6/src/test/java/com/baeldung/javadoublevsbigdecimal/BigDecimalUnitTest.java

@@ -0,0 +1,42 @@
+package com.baeldung.javadoublevsbigdecimal;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+import org.junit.jupiter.api.Test;
+
+public class BigDecimalUnitTest {
+
+    private BigDecimal bigDecimal1 = new BigDecimal("124567890.0987654321");
+    private BigDecimal bigDecimal2 = new BigDecimal("987654321.123456789");
+
+    @Test
+    public void givenTwoBigDecimals_whenAdd_thenCorrect() {
+        BigDecimal expected = new BigDecimal("1112222211.2222222211");
+        BigDecimal actual = bigDecimal1.add(bigDecimal2);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void givenTwoBigDecimals_whenMultiply_thenCorrect() {
+        BigDecimal expected = new BigDecimal("123030014929277547.5030955772112635269");
+        BigDecimal actual = bigDecimal1.multiply(bigDecimal2);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void givenTwoBigDecimals_whenSubtract_thenCorrect() {
+        BigDecimal expected = new BigDecimal("-863086431.0246913569");
+        BigDecimal actual = bigDecimal1.subtract(bigDecimal2);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void givenTwoBigDecimals_whenDivide_thenCorrect() {
+        BigDecimal expected = new BigDecimal("0.13");
+        BigDecimal actual = bigDecimal1.divide(bigDecimal2, 2, RoundingMode.HALF_UP);
+        assertEquals(expected, actual);
+    }
+}

core-java-modules/core-java-numbers-6/src/test/java/com/baeldung/javadoublevsbigdecimal/JavaDoubleUnitTest.java

@@ -0,0 +1,15 @@
+package com.baeldung.javadoublevsbigdecimal;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class JavaDoubleUnitTest {
+
+    @Test
+    public void givenDoubleLiteral_whenAssigningToDoubleVariable_thenValueIsNotExactlyEqual() {
+        double doubleValue = 0.1;
+        double epsilon = 0.0000000000000001;
+        assertEquals(0.1, doubleValue, epsilon);
+    }
+}

core-java-modules/core-java-numbers-conversions/src/test/java/com/baeldung/floatdoubleconversions/FloatDoubleConversionsTest.java

@@ -9,25 +9,21 @@ public class FloatDoubleConversionsTest {
     public void whenDoubleType_thenFloatTypeSuccess(){
         double interestRatesYearly = 13.333333333333334;
         float interest = (float) interestRatesYearly;
-        System.out.println(interest);  //13.333333
+        Assert.assertEquals(13.333333f, interest, 0.000004f);
-        Assert.assertTrue(Float.class.isInstance(interest));//true
 
         Double monthlyRates = 2.111111111111112;
         float rates = monthlyRates.floatValue();
-        System.out.println(rates);  //2.1111112
+        Assert.assertEquals(2.1111112f, rates, 0.00000013);
-        Assert.assertTrue(Float.class.isInstance(rates));//true
     }
     @Test
     public void whenFloatType_thenDoubleTypeSuccess(){
         float gradeAverage =2.05f;
         double average = gradeAverage;
-        System.out.println(average);  //2.049999952316284
+        Assert.assertEquals(2.05, average, 0.06);
-        Assert.assertTrue(Double.class.isInstance(average));//true
 
         Float monthlyRates = 2.1111112f;
         Double rates = monthlyRates.doubleValue();
-        System.out.println(rates);  //2.1111112
+        Assert.assertEquals(2.11111112, rates, 0.0000002);//true
-        Assert.assertTrue(Double.class.isInstance(rates));//true
     }
 
 }

core-java-modules/core-java-numbers-conversions/src/test/java/com/baeldung/floattobigdecimal/FloatToBigDecimalUnitTest.java

@@ -0,0 +1,49 @@
+package com.baeldung.floattobigdecimal;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import java.math.BigDecimal;
+
+import org.junit.jupiter.api.Test;
+
+class FloatToBigDecimalUnitTest {
+
+    @Test
+    public void whenFloatComparedWithDifferentValues_thenCouldMatch() {
+        assertNotEquals(1.1f, 1.09f);
+        assertEquals(1.1f, 1.09999999f);
+    }
+
+    @Test
+    public void whenCreatedFromFloat_thenMatchesInternallyStoredValue() {
+        float floatToConvert = 1.10000002384185791015625f;
+        BigDecimal bdFromFloat = new BigDecimal(floatToConvert);
+        assertEquals("1.10000002384185791015625", bdFromFloat.toString());
+    }
+
+    @Test
+    public void whenCreatedFromString_thenPreservesTheOriginal() {
+        BigDecimal bdFromString = new BigDecimal("1.1");
+        assertEquals("1.1", bdFromString.toString());
+    }
+
+    @Test
+    public void whenCreatedFromFloatConvertedToString_thenFloatInternalValueGetsTruncated() {
+        String floatValue = Float.toString(1.10000002384185791015625f);
+        BigDecimal bdFromString = new BigDecimal(floatValue);
+        assertEquals("1.1", floatValue);
+        assertEquals("1.1", bdFromString.toString());
+    }
+
+    @Test
+    public void whenCreatedByValueOf_thenFloatValueGetsTruncated() {
+        assertEquals("1.100000023841858", BigDecimal.valueOf(1.10000002384185791015625f).toString());
+    }
+
+    @Test
+    public void whenDoubleConvertsFloatToString_thenFloatValueGetsTruncated() {
+        assertEquals("1.100000023841858", Double.toString(1.10000002384185791015625f));
+    }
+
+}

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

@@ -0,0 +1,2 @@
+### Relevant Articles:
+- [Is Java Reflection Bad Practice?](https://www.baeldung.com/java-reflection-bad-practice)

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

@@ -0,0 +1,78 @@
+<?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-reflection-3</artifactId>
+    <name>core-java-reflection-3</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-test</artifactId>
+            <version>${spring.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.reflections</groupId>
+            <artifactId>reflections</artifactId>
+            <version>${reflections.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-reflection-3</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${source.version}</source>
+                    <target>${target.version}</target>
+                    <compilerArgument>-parameters</compilerArgument>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.jacoco</groupId>
+                <artifactId>jacoco-maven-plugin</artifactId>
+                <version>0.8.8</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>prepare-agent</goal>
+                        </goals>
+                    </execution>
+                    <execution>
+                        <id>report</id>
+                        <phase>prepare-package</phase>
+                        <goals>
+                            <goal>report</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <reflections.version>0.9.12</reflections.version>
+        <source.version>1.8</source.version>
+        <target.version>1.8</target.version>
+        <spring.version>5.3.4</spring.version>
+    </properties>
+
+</project>

core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/encapsulation/MyClass.java

@@ -0,0 +1,11 @@
+package com.baeldung.reflection.disadvantages.encapsulation;
+
+public class MyClass {
+
+    private String veryPrivateField;
+
+    public MyClass() {
+
+        this.veryPrivateField = "Secret Information";
+    }
+}

core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/performance/BenchmarkRunner.java

@@ -0,0 +1,7 @@
+package com.baeldung.reflection.disadvantages.performance;
+
+public class BenchmarkRunner {
+    public static void main(String[] args) throws Exception {
+        org.openjdk.jmh.Main.main(args);
+    }
+}

core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/performance/InitializationBenchmark.java

@@ -0,0 +1,29 @@
+package com.baeldung.reflection.disadvantages.performance;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.concurrent.TimeUnit;
+
+public class InitializationBenchmark {
+
+    @Benchmark
+    @Fork(value = 1, warmups = 1)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    @BenchmarkMode(Mode.AverageTime)
+    public void directInit() {
+
+        Person person = new Person("John", "Doe", 50);
+    }
+
+    @Benchmark
+    @Fork(value = 1, warmups = 1)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    @BenchmarkMode(Mode.AverageTime)
+    public void reflectiveInit() throws NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException {
+
+        Constructor<Person> constructor = Person.class.getDeclaredConstructor(String.class, String.class, Integer.class);
+        Person person = constructor.newInstance("John", "Doe", 50);
+    }
+}

core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/performance/MethodInvocationBenchmark.java

@@ -0,0 +1,48 @@
+package com.baeldung.reflection.disadvantages.performance;
+
+import org.openjdk.jmh.annotations.*;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.concurrent.TimeUnit;
+
+public class MethodInvocationBenchmark {
+
+    @Benchmark
+    @Fork(value = 1, warmups = 1)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    @BenchmarkMode(Mode.AverageTime)
+    public void directCall() {
+
+        directCall(new Person("John", "Doe", 50));
+    }
+
+    @Benchmark
+    @Fork(value = 1, warmups = 1)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    @BenchmarkMode(Mode.AverageTime)
+    public void reflectiveCall() throws InvocationTargetException, NoSuchMethodException, IllegalAccessException {
+
+        reflectiveCall(new Person("John", "Doe", 50));
+    }
+
+
+    private void directCall(Person person) {
+
+        person.getFirstName();
+        person.getLastName();
+        person.getAge();
+    }
+
+    private void reflectiveCall(Person person) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
+
+        Method getFirstNameMethod = Person.class.getMethod("getFirstName");
+        getFirstNameMethod.invoke(person);
+
+        Method getLastNameMethod = Person.class.getMethod("getLastName");
+        getLastNameMethod.invoke(person);
+
+        Method getAgeMethod = Person.class.getMethod("getAge");
+        getAgeMethod.invoke(person);
+    }
+}

core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/performance/Person.java

@@ -0,0 +1,38 @@
+package com.baeldung.reflection.disadvantages.performance;
+
+public class Person {
+
+    private String firstName;
+    private String lastName;
+    private Integer age;
+
+    public Person(String firstName, String lastName, Integer age) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.age = age;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public Integer getAge() {
+        return age;
+    }
+
+    public void setAge(Integer age) {
+        this.age = age;
+    }
+}

core-java-modules/core-java-reflection-3/src/test/java/com/baeldung/reflection/disadvantages/encapsulation/ReflectionEncapsulationUnitTest.java

@@ -0,0 +1,21 @@
+package com.baeldung.reflection.disadvantages.encapsulation;
+
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Field;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ReflectionEncapsulationUnitTest {
+
+    @Test
+    public void givenPrivateField_whenUsingReflection_thenIsAccessible() throws IllegalAccessException, NoSuchFieldException {
+        MyClass myClassInstance = new MyClass();
+
+        Field privateField = MyClass.class.getDeclaredField("veryPrivateField");
+        privateField.setAccessible(true);
+
+        String accessedField = privateField.get(myClassInstance).toString();
+        assertEquals(accessedField, "Secret Information");
+    }
+}

core-java-modules/core-java-security/src/main/java/com/baeldung/ssl/SecureConnection.java

@@ -7,7 +7,7 @@ import javax.net.ssl.SSLSocket;
 import javax.net.ssl.SSLSocketFactory;
 
 public class SecureConnection {
-    
+
     public static void main(String[] args) {
         if (args.length != 2) {
             System.out.println("Use: SecureConnection host port");
@@ -20,20 +20,20 @@ public class SecureConnection {
             SSLSocket sslsocket = (SSLSocket) sslsocketfactory.createSocket(host, port);
             InputStream in = sslsocket.getInputStream();
             OutputStream out = sslsocket.getOutputStream();
-            
+
             out.write(1);
-            
+
             while (in.available() > 0) {
                 System.out.print(in.read());
             }
-            
+
             System.out.println("Secured connection performed successfully");
-            
+
         } catch (Exception exception) {
             exception.printStackTrace();
         }
     }
-    
+
     /**
      * Get the host from arguments
      * @param args the arguments
@@ -42,7 +42,7 @@ public class SecureConnection {
     private static String getHost(String[] args) {
         return args[0];
     }
-    
+
     /**
      * Get the port from arguments
      * @param args the arguments

core-java-modules/core-java-security/src/main/java/com/baeldung/ssl/example/SimpleClient.java

@@ -15,10 +15,8 @@ public class SimpleClient {
         SocketFactory factory = SSLSocketFactory.getDefault();
 
         try (Socket connection = factory.createSocket(host, port)) {
-            ((SSLSocket) connection).setEnabledCipherSuites(
+            ((SSLSocket) connection).setEnabledCipherSuites(new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256" });
-              new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256"});
+            ((SSLSocket) connection).setEnabledProtocols(new String[] { "TLSv1.2" });
-            ((SSLSocket) connection).setEnabledProtocols(
-              new String[] { "TLSv1.2"});
             SSLParameters sslParams = new SSLParameters();
             sslParams.setEndpointIdentificationAlgorithm("HTTPS");
             ((SSLSocket) connection).setSSLParameters(sslParams);
@@ -28,6 +26,7 @@ public class SimpleClient {
     }
 
     public static void main(String[] args) throws IOException {
+        System.setProperty("javax.net.debug", "ssl:handshake");
         System.out.println(startClient("localhost", 8443));
     }
 }

core-java-modules/core-java-security/src/main/java/com/baeldung/ssl/example/SimpleServer.java

@@ -14,11 +14,10 @@ public class SimpleServer {
         ServerSocketFactory factory = SSLServerSocketFactory.getDefault();
 
         try (ServerSocket listener = factory.createServerSocket(port)) {
+            System.setProperty("javax.net.debug", "ssl:handshake");
             ((SSLServerSocket) listener).setNeedClientAuth(true);
-            ((SSLServerSocket) listener).setEnabledCipherSuites(
+            ((SSLServerSocket) listener).setEnabledCipherSuites(new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256" });
-              new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256"});
+            ((SSLServerSocket) listener).setEnabledProtocols(new String[] { "TLSv1.2" });
-            ((SSLServerSocket) listener).setEnabledProtocols(
-              new String[] { "TLSv1.2"});
             while (true) {
                 try (Socket socket = listener.accept()) {
                     PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
@@ -29,6 +28,7 @@ public class SimpleServer {
     }
 
     public static void main(String[] args) throws IOException {
+        System.setProperty("javax.net.debug", "ssl:handshake");
         startServer(8443);
     }
 }

core-java-modules/core-java-streams-2/README.md

@@ -4,12 +4,9 @@ This module contains articles about the Stream API in Java.
 
 ### Relevant Articles:
 - [The Java 8 Stream API Tutorial](https://www.baeldung.com/java-8-streams)
-- [Introduction to Java 8 Streams](https://www.baeldung.com/java-8-streams-introduction)
 - [Java 8 Stream findFirst() vs. findAny()](https://www.baeldung.com/java-stream-findfirst-vs-findany)
-- [Guide to Stream.reduce()](https://www.baeldung.com/java-stream-reduce)
 - [Java IntStream Conversions](https://www.baeldung.com/java-intstream-convert)
 - [Java 8 Streams peek() API](https://www.baeldung.com/java-streams-peek-api)
-- [Working With Maps Using Streams](https://www.baeldung.com/java-maps-streams)
 - [Collect a Java Stream to an Immutable Collection](https://www.baeldung.com/java-stream-immutable-collection)
 - [How to Add a Single Element to a Stream](https://www.baeldung.com/java-stream-append-prepend)
 - [Operating on and Removing an Item from Stream](https://www.baeldung.com/java-use-remove-item-stream)

core-java-modules/core-java-streams-2/src/test/java/com/baeldung/streams/Java8StreamApiUnitTest.java

@@ -1,6 +1,7 @@
 package com.baeldung.streams;
 
 import org.junit.Before;
+import org.junit.Ignore;
 import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -37,6 +38,7 @@ public class Java8StreamApiUnitTest {
         assertEquals(list.size() - 1, size);
     }
 
+    @Ignore
     @Test
     public void checkOrder_whenChangeQuantityOfMethodCalls_thenCorrect() {
 

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

@@ -2,8 +2,7 @@
 
 This module contains articles about the Stream API in Java.
 
-### Relevant Articles: 
+### Relevant Articles:
-- [The Difference Between map() and flatMap()](https://www.baeldung.com/java-difference-map-and-flatmap)
 - [How to Use if/else Logic in Java 8 Streams](https://www.baeldung.com/java-8-streams-if-else-logic)
 - [The Difference Between Collection.stream().forEach() and Collection.forEach()](https://www.baeldung.com/java-collection-stream-foreach)
 - [Primitive Type Streams in Java 8](https://www.baeldung.com/java-8-primitive-streams)
@@ -12,5 +11,4 @@ This module contains articles about the Stream API in Java.
 - [Should We Close a Java Stream?](https://www.baeldung.com/java-stream-close)
 - [Returning Stream vs. Collection](https://www.baeldung.com/java-return-stream-collection)
 - [Convert a Java Enumeration Into a Stream](https://www.baeldung.com/java-enumeration-to-stream)
-- [When to Use a Parallel Stream in Java](https://www.baeldung.com/java-when-to-use-parallel-stream)
 - More articles: [[<-- prev>]](/../core-java-streams-2)

core-java-modules/core-java-streams-5/README.md

@@ -3,3 +3,4 @@
 - [Working With Empty Stream in Java](https://www.baeldung.com/java-empty-stream)
 - [Aggregate Runtime Exceptions in Java Streams](https://www.baeldung.com/java-streams-aggregate-exceptions)
 - [Streams vs. Loops in Java](https://www.baeldung.com/java-streams-vs-loops)
+- [Partition a Stream in Java](https://www.baeldung.com/java-partition-stream)

core-java-modules/core-java-streams-5/src/main/java/com/baeldung/skippingelements/SkippingCollector.java

@@ -0,0 +1,32 @@
+package com.baeldung.skippingelements;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.BinaryOperator;
+import java.util.stream.Collector;
+
+class SkippingCollector {
+    private static final BinaryOperator<SkippingCollector> IGNORE_COMBINE = (a, b) -> a;
+    private final int skip;
+    private final List<String> list = new ArrayList<>();
+    private int currentIndex = 0;
+    private SkippingCollector(int skip) {
+        this.skip = skip;
+    }
+
+    private void accept(String item) {
+        final int index = ++currentIndex % skip;
+        if (index == 0)
+            list.add(item);
+    }
+    private List<String> getResult() {
+        return list;
+    }
+
+    public static Collector<String, SkippingCollector, List<String>> collector(int skip) {
+        return Collector.of(() -> new SkippingCollector(skip),
+            SkippingCollector::accept,
+            IGNORE_COMBINE,
+            SkippingCollector::getResult);
+    }
+}

core-java-modules/core-java-streams-5/src/main/java/com/baeldung/skippingelements/SkippingElements.java

@@ -0,0 +1,65 @@
+package com.baeldung.skippingelements;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+public class SkippingElements {
+
+    private SkippingElements() {
+    }
+
+    public static List<String> skipNthElementInListWithFilter(List<String> sourceList, int n) {
+return IntStream.range(0, sourceList.size())
+    .filter(s -> (s + 1) % n == 0)
+    .mapToObj(sourceList::get)
+    .collect(Collectors.toList());
+    }
+
+    public static List<String> skipNthElementInListWithIterate(List<String> sourceList, int n) {
+int limit = sourceList.size() / n;
+return IntStream.iterate(n - 1, i -> (i + n))
+    .limit(limit)
+    .mapToObj(sourceList::get)
+    .collect(Collectors.toList());
+    }
+
+    public static List<String> skipNthElementInListWithSublist(List<String> sourceList, int n) {
+int limit = sourceList.size() / n;
+return Stream.iterate(sourceList, s -> s.subList(n, s.size()))
+    .limit(limit)
+    .map(s -> s.get(n - 1))
+    .collect(Collectors.toList());
+    }
+
+    public static List<String> skipNthElementInListWithFor(List<String> sourceList, int n) {
+List<String> result = new ArrayList<>();
+for (int i = n - 1; i < sourceList.size(); i += n) {
+    result.add(sourceList.get(i));
+}
+return result;
+    }
+
+    public static List<String> skipNthElementInListWithIterator(Stream<String> sourceStream, int n) {
+List<String> result = new ArrayList<>();
+final Iterator<String> iterator = sourceStream.iterator();
+int count = 0;
+while (iterator.hasNext()) {
+    if (count % n == n - 1) {
+        result.add(iterator.next());
+    } else {
+        iterator.next();
+    }
+    ++count;
+}
+return result;
+    }
+
+public static List<String> skipNthElementInStreamWithCollector(Stream<String> sourceStream, int n) {
+    return sourceStream.collect(SkippingCollector.collector(n));
+}
+
+}

core-java-modules/core-java-streams-5/src/test/java/com/baeldung/skippingelements/SkippingElementsUnitTest.java

@@ -0,0 +1,114 @@
+package com.baeldung.skippingelements;
+
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class SkippingElementsUnitTest {
+
+    private static Stream<Arguments> testSource() {
+        return Stream.of(
+            Arguments.of(
+                List.of("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen",
+                    "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen", "Twenty", "Twenty One", "Twenty Two",
+                    "Twenty Three", "Twenty Four", "Twenty Five", "Twenty Six", "Twenty Seven", "Twenty Eight", "Twenty Nine", "Thirty",
+                    "Thirty One", "Thirty Two", "Thirty Three"),
+                List.of("Three", "Six", "Nine", "Twelve", "Fifteen", "Eighteen", "Twenty One", "Twenty Four", "Twenty Seven", "Thirty", "Thirty Three"),
+                3),
+            Arguments.of(
+                List.of("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen",
+                    "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen", "Twenty", "Twenty One", "Twenty Two",
+                    "Twenty Three", "Twenty Four", "Twenty Five", "Twenty Six", "Twenty Seven", "Twenty Eight", "Twenty Nine", "Thirty",
+                    "Thirty One", "Thirty Two", "Thirty Three"),
+                List.of("Five", "Ten", "Fifteen", "Twenty", "Twenty Five", "Thirty"),
+                5),
+            Arguments.of(
+                List.of("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen",
+                    "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen", "Twenty", "Twenty One", "Twenty Two",
+                    "Twenty Three", "Twenty Four", "Twenty Five", "Twenty Six", "Twenty Seven", "Twenty Eight", "Twenty Nine", "Thirty",
+                    "Thirty One", "Thirty Two", "Thirty Three"),
+                List.of("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen",
+                    "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen", "Twenty", "Twenty One", "Twenty Two",
+                    "Twenty Three", "Twenty Four", "Twenty Five", "Twenty Six", "Twenty Seven", "Twenty Eight", "Twenty Nine", "Thirty",
+                    "Thirty One", "Thirty Two", "Thirty Three"),
+                1),
+            Arguments.of(
+                List.of("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"),
+                List.of("Wednesday", "Saturday"),
+                3),
+            Arguments.of(
+                List.of("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"),
+                List.of("Friday"),
+                5),
+            Arguments.of(
+                List.of("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"),
+                List.of("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"),
+                1),
+            Arguments.of(
+                List.of("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November",
+                    "December"),
+                List.of("March", "June", "September", "December"),
+                3),
+            Arguments.of(
+                List.of("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November",
+                    "December"),
+                List.of("May", "October"),
+                5),
+            Arguments.of(
+                List.of("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November",
+                    "December"),
+                List.of("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November",
+                    "December"),
+                1)
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("testSource")
+    void givenListSkipNthElementInListWithFilterTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
+        final List<String> actual = SkippingElements.skipNthElementInListWithFilter(input, n);
+        assertEquals(expected, actual);
+    }
+
+    @ParameterizedTest
+    @MethodSource("testSource")
+    void givenListSkipNthElementInListWithIterateTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
+        final List<String> actual = SkippingElements.skipNthElementInListWithIterate(input, n);
+        assertEquals(expected, actual);
+    }
+
+    @ParameterizedTest
+    @MethodSource("testSource")
+    void givenListSkipNthElementInListWithSublistTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
+        final List<String> actual = SkippingElements.skipNthElementInListWithSublist(input, n);
+        assertEquals(expected, actual);
+    }
+
+    @ParameterizedTest
+    @MethodSource("testSource")
+    void givenListSkipNthElementInListWithForTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
+        final List<String> actual = SkippingElements.skipNthElementInListWithFor(input, n);
+        assertEquals(expected, actual);
+    }
+
+    @ParameterizedTest
+    @MethodSource("testSource")
+    void givenListSkipNthElementInStreamWithIteratorTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
+        final Stream<String> inputStream = input.stream();
+        final List<String> actual = SkippingElements.skipNthElementInListWithIterator(inputStream, n);
+        assertEquals(expected, actual);
+    }
+
+    @ParameterizedTest
+    @MethodSource("testSource")
+    void givenListSkipNthElementInStreamWithCollectorShouldFilterNthElement(List<String> input, List<String> expected, int n) {
+        final Stream<String> inputStream = input.stream();
+        final List<String> actual = SkippingElements.skipNthElementInStreamWithCollector(inputStream, n);
+        assertEquals(expected, actual);
+    }
+}

core-java-modules/core-java-streams-simple/README.md

@@ -0,0 +1,14 @@
+## Java Streams Ebook
+
+This module contains articles about Streams that are part of the Java Streams Ebook.
+
+### Relevant Articles
+
+- [Introduction to Java 8 Streams](https://www.baeldung.com/java-8-streams-introduction)
+- [Guide to Java 8’s Collectors](https://www.baeldung.com/java-8-collectors)
+- [Java Stream Filter with Lambda Expression](https://www.baeldung.com/java-stream-filter-lambda)
+- [Working With Maps Using Streams](https://www.baeldung.com/java-maps-streams)
+- [The Difference Between map() and flatMap()](https://www.baeldung.com/java-difference-map-and-flatmap)
+- [When to Use a Parallel Stream in Java](https://www.baeldung.com/java-when-to-use-parallel-stream)
+- [Guide to Java 8 groupingBy Collector](https://www.baeldung.com/java-groupingby-collector)
+- [Guide to Stream.reduce()](https://www.baeldung.com/java-stream-reduce)

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

@@ -0,0 +1,52 @@
+<?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-streams-simple</artifactId>
+    <name>core-java-streams-simple</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.pivovarit</groupId>
+            <artifactId>throwing-function</artifactId>
+            <version>${throwing-function.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-streams-simple</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <throwing-function.version>1.5.1</throwing-function.version>
+        <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>
+    </properties>
+
+</project>

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/filter/Customer.java

@@ -0,0 +1,56 @@
+package com.baeldung.streams.filter;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+import javax.net.ssl.HttpsURLConnection;
+
+public class Customer {
+    private String name;
+    private int points;
+    private String profilePhotoUrl;
+
+    public Customer(String name, int points) {
+        this(name, points, "");
+    }
+
+    public Customer(String name, int points, String profilePhotoUrl) {
+        this.name = name;
+        this.points = points;
+        this.profilePhotoUrl = profilePhotoUrl;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getPoints() {
+        return points;
+    }
+
+    public boolean hasOver(int points) {
+        return this.points > points;
+    }
+
+    public boolean hasOverHundredPoints() {
+        return this.points > 100;
+    }
+
+    public boolean hasValidProfilePhoto() throws IOException {
+        URL url = new URL(this.profilePhotoUrl);
+        HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
+        return connection.getResponseCode() == HttpURLConnection.HTTP_OK;
+    }
+
+    public boolean hasValidProfilePhotoWithoutCheckedException() {
+        try {
+            URL url = new URL(this.profilePhotoUrl);
+            HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
+            return connection.getResponseCode() == HttpURLConnection.HTTP_OK;
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+}

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/groupingby/BlogPost.java

@@ -1,4 +1,4 @@
-package com.baeldung.java_16_features.groupingby;
+package com.baeldung.streams.groupingby;
 
 import java.util.IntSummaryStatistics;
 

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/groupingby/BlogPostType.java

@@ -1,4 +1,4 @@
-package com.baeldung.java_16_features.groupingby;
+package com.baeldung.streams.groupingby;
 
 public enum BlogPostType {
     NEWS, REVIEW, GUIDE

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/groupingby/Tuple.java

@@ -1,4 +1,4 @@
-package com.baeldung.java_16_features.groupingby;
+package com.baeldung.streams.groupingby;
 
 import java.util.Objects;
 

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/application/Application.java

@@ -1,8 +1,7 @@
-package com.baeldung.reduce.application;
+package com.baeldung.streams.reduce.application;
+
+import com.baeldung.streams.reduce.entities.User;
 
-import com.baeldung.reduce.entities.User;
-import com.baeldung.reduce.utilities.NumberUtils;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/benchmarks/JMHStreamReduceBenchMark.java

@@ -1,6 +1,6 @@
-package com.baeldung.reduce.benchmarks;
+package com.baeldung.streams.reduce.benchmarks;
 
-import com.baeldung.reduce.entities.User;
+import com.baeldung.streams.reduce.entities.User;
 import java.util.ArrayList;
 import java.util.List;
 import org.openjdk.jmh.annotations.Benchmark;

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/entities/Rating.java

@@ -1,4 +1,4 @@
-package com.baeldung.reduce.entities;
+package com.baeldung.streams.reduce.entities;
 
 import java.util.ArrayList;
 import java.util.List;

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/entities/Review.java

@@ -1,4 +1,4 @@
-package com.baeldung.reduce.entities;
+package com.baeldung.streams.reduce.entities;
 
 public class Review {
 

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/entities/User.java

@@ -1,4 +1,4 @@
-package com.baeldung.reduce.entities;
+package com.baeldung.streams.reduce.entities;
 
 public class User {
 

core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/utilities/NumberUtils.java

@@ -1,4 +1,4 @@
-package com.baeldung.reduce.utilities;
+package com.baeldung.streams.reduce.utilities;
 
 import java.util.List;
 import java.util.function.BiFunction;

core-java-modules/core-java-streams-simple/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/collectors/Java8CollectorsUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.collectors;
+package com.baeldung.streams.collectors;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;

core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/filter/StreamFilterUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.stream.filter;
+package com.baeldung.streams.filter;
 
 import org.junit.jupiter.api.Test;
 import com.pivovarit.function.ThrowingPredicate;
@@ -14,10 +14,10 @@ import java.util.stream.Stream;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
 
-public class StreamFilterUnitTest {
+class StreamFilterUnitTest {
 
     @Test
-    public void givenListOfCustomers_whenFilterByPoints_thenGetTwo() {
+    void givenListOfCustomers_whenFilterByPoints_thenGetTwo() {
         Customer john = new Customer("John P.", 15);
         Customer sarah = new Customer("Sarah M.", 200);
         Customer charles = new Customer("Charles B.", 150);
@@ -53,7 +53,7 @@ public class StreamFilterUnitTest {
     }
 
     @Test
-    public void givenListOfCustomers_whenFilterByMethodReference_thenGetTwo() {
+    void givenListOfCustomers_whenFilterByMethodReference_thenGetTwo() {
         Customer john = new Customer("John P.", 15);
         Customer sarah = new Customer("Sarah M.", 200);
         Customer charles = new Customer("Charles B.", 150);
@@ -70,7 +70,7 @@ public class StreamFilterUnitTest {
     }
 
     @Test
-    public void givenListOfCustomersWithOptional_whenFilterBy100Points_thenGetTwo() {
+    void givenListOfCustomersWithOptional_whenFilterBy100Points_thenGetTwo() {
         Optional<Customer> john = Optional.of(new Customer("John P.", 15));
         Optional<Customer> sarah = Optional.of(new Customer("Sarah M.", 200));
         Optional<Customer> mary = Optional.of(new Customer("Mary T.", 300));
@@ -89,7 +89,7 @@ public class StreamFilterUnitTest {
     }
 
     @Test
-    public void givenListOfCustomers_whenFilterWithCustomHandling_thenThrowException() {
+    void givenListOfCustomers_whenFilterWithCustomHandling_thenThrowException() {
         Customer john = new Customer("John P.", 15, "https://images.unsplash.com/photo-1543320485-d0d5a49c2b2e");
         Customer sarah = new Customer("Sarah M.", 200);
         Customer charles = new Customer("Charles B.", 150);
@@ -103,7 +103,7 @@ public class StreamFilterUnitTest {
     }
 
     @Test
-    public void givenListOfCustomers_whenFilterWithThrowingFunction_thenThrowException() {
+    void givenListOfCustomers_whenFilterWithThrowingFunction_thenThrowException() {
         Customer john = new Customer("John P.", 15, "https://images.unsplash.com/photo-1543320485-d0d5a49c2b2e");
         Customer sarah = new Customer("Sarah M.", 200);
         Customer charles = new Customer("Charles B.", 150);

core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/flatmap/map/Java8MapAndFlatMapUnitTest.java

@@ -1,6 +1,7 @@
 package com.baeldung.streams.flatmap.map;
 
-import org.junit.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.junit.jupiter.api.Test;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -10,12 +11,12 @@ import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import static java.util.Arrays.asList;
-import static org.junit.Assert.assertEquals;
 
-public class Java8MapAndFlatMapUnitTest {
+
+class Java8MapAndFlatMapUnitTest {
 
     @Test
-    public void givenStream_whenCalledMap_thenProduceList() {
+    void givenStream_whenCalledMap_thenProduceList() {
         List<String> myList = Stream.of("a", "b")
             .map(String::toUpperCase)
             .collect(Collectors.toList());
@@ -23,7 +24,7 @@ public class Java8MapAndFlatMapUnitTest {
     }
 
     @Test
-    public void givenStream_whenCalledFlatMap_thenProduceFlattenedList() throws Exception {
+    void givenStream_whenCalledFlatMap_thenProduceFlattenedList() {
         List<List<String>> list = Arrays.asList(Arrays.asList("a"), Arrays.asList("b"));
         System.out.println(list);
 
@@ -33,13 +34,13 @@ public class Java8MapAndFlatMapUnitTest {
     }
 
     @Test
-    public void givenOptional_whenCalledMap_thenProduceOptional() {
+    void givenOptional_whenCalledMap_thenProduceOptional() {
         Optional<String> s = Optional.of("test");
         assertEquals(Optional.of("TEST"), s.map(String::toUpperCase));
     }
 
     @Test
-    public void givenOptional_whenCalledFlatMap_thenProduceFlattenedOptional() {
+    void givenOptional_whenCalledFlatMap_thenProduceFlattenedOptional() {
         assertEquals(Optional.of(Optional.of("STRING")), Optional.of("string")
             .map(s -> Optional.of("STRING")));
 

core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/groupingby/JavaGroupingByCollectorUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.java_16_features.groupingby;
+package com.baeldung.streams.groupingby;
 
 import static java.util.Comparator.comparingInt;
 import static java.util.stream.Collectors.averagingInt;
@@ -33,13 +33,13 @@ import org.apache.commons.lang3.tuple.ImmutablePair;
 import org.apache.commons.lang3.tuple.Pair;
 import org.junit.jupiter.api.Test;
 
-public class JavaGroupingByCollectorUnitTest {
+class JavaGroupingByCollectorUnitTest {
 
     private static final List<BlogPost> posts = Arrays.asList(new BlogPost("News item 1", "Author 1", BlogPostType.NEWS, 15), new BlogPost("Tech review 1", "Author 2", BlogPostType.REVIEW, 5),
         new BlogPost("Programming guide", "Author 1", BlogPostType.GUIDE, 20), new BlogPost("News item 2", "Author 2", BlogPostType.NEWS, 35), new BlogPost("Tech review 2", "Author 1", BlogPostType.REVIEW, 15));
 
     @Test
-    public void givenAListOfPosts_whenGroupedByType_thenGetAMapBetweenTypeAndPosts() {
+    void givenAListOfPosts_whenGroupedByType_thenGetAMapBetweenTypeAndPosts() {
         Map<BlogPostType, List<BlogPost>> postsPerType = posts.stream()
             .collect(groupingBy(BlogPost::getType));
 
@@ -52,7 +52,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByTypeAndTheirTitlesAreJoinedInAString_thenGetAMapBetweenTypeAndCsvTitles() {
+    void givenAListOfPosts_whenGroupedByTypeAndTheirTitlesAreJoinedInAString_thenGetAMapBetweenTypeAndCsvTitles() {
         Map<BlogPostType, String> postsPerType = posts.stream()
             .collect(groupingBy(BlogPost::getType, mapping(BlogPost::getTitle, joining(", ", "Post titles: [", "]"))));
 
@@ -62,7 +62,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByTypeAndSumTheLikes_thenGetAMapBetweenTypeAndPostLikes() {
+    void givenAListOfPosts_whenGroupedByTypeAndSumTheLikes_thenGetAMapBetweenTypeAndPostLikes() {
         Map<BlogPostType, Integer> likesPerType = posts.stream()
             .collect(groupingBy(BlogPost::getType, summingInt(BlogPost::getLikes)));
 
@@ -75,7 +75,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByTypeInAnEnumMap_thenGetAnEnumMapBetweenTypeAndPosts() {
+    void givenAListOfPosts_whenGroupedByTypeInAnEnumMap_thenGetAnEnumMapBetweenTypeAndPosts() {
         EnumMap<BlogPostType, List<BlogPost>> postsPerType = posts.stream()
             .collect(groupingBy(BlogPost::getType, () -> new EnumMap<>(BlogPostType.class), toList()));
 
@@ -88,7 +88,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByTypeInSets_thenGetAMapBetweenTypesAndSetsOfPosts() {
+    void givenAListOfPosts_whenGroupedByTypeInSets_thenGetAMapBetweenTypesAndSetsOfPosts() {
         Map<BlogPostType, Set<BlogPost>> postsPerType = posts.stream()
             .collect(groupingBy(BlogPost::getType, toSet()));
 
@@ -101,7 +101,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByTypeConcurrently_thenGetAMapBetweenTypeAndPosts() {
+    void givenAListOfPosts_whenGroupedByTypeConcurrently_thenGetAMapBetweenTypeAndPosts() {
         ConcurrentMap<BlogPostType, List<BlogPost>> postsPerType = posts.parallelStream()
             .collect(groupingByConcurrent(BlogPost::getType));
 
@@ -114,7 +114,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByTypeAndAveragingLikes_thenGetAMapBetweenTypeAndAverageNumberOfLikes() {
+    void givenAListOfPosts_whenGroupedByTypeAndAveragingLikes_thenGetAMapBetweenTypeAndAverageNumberOfLikes() {
         Map<BlogPostType, Double> averageLikesPerType = posts.stream()
             .collect(groupingBy(BlogPost::getType, averagingInt(BlogPost::getLikes)));
 
@@ -127,7 +127,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByTypeAndCounted_thenGetAMapBetweenTypeAndNumberOfPosts() {
+    void givenAListOfPosts_whenGroupedByTypeAndCounted_thenGetAMapBetweenTypeAndNumberOfPosts() {
         Map<BlogPostType, Long> numberOfPostsPerType = posts.stream()
             .collect(groupingBy(BlogPost::getType, counting()));
 
@@ -140,7 +140,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByTypeAndMaxingLikes_thenGetAMapBetweenTypeAndMaximumNumberOfLikes() {
+    void givenAListOfPosts_whenGroupedByTypeAndMaxingLikes_thenGetAMapBetweenTypeAndMaximumNumberOfLikes() {
         Map<BlogPostType, Optional<BlogPost>> maxLikesPerPostType = posts.stream()
             .collect(groupingBy(BlogPost::getType, maxBy(comparingInt(BlogPost::getLikes))));
 
@@ -164,7 +164,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByAuthorAndThenByType_thenGetAMapBetweenAuthorAndMapsBetweenTypeAndBlogPosts() {
+    void givenAListOfPosts_whenGroupedByAuthorAndThenByType_thenGetAMapBetweenAuthorAndMapsBetweenTypeAndBlogPosts() {
         Map<String, Map<BlogPostType, List<BlogPost>>> map = posts.stream()
             .collect(groupingBy(BlogPost::getAuthor, groupingBy(BlogPost::getType)));
 
@@ -189,7 +189,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByTypeAndSummarizingLikes_thenGetAMapBetweenTypeAndSummary() {
+    void givenAListOfPosts_whenGroupedByTypeAndSummarizingLikes_thenGetAMapBetweenTypeAndSummary() {
         Map<BlogPostType, IntSummaryStatistics> likeStatisticsPerType = posts.stream()
             .collect(groupingBy(BlogPost::getType, summarizingInt(BlogPost::getLikes)));
 
@@ -203,7 +203,7 @@ public class JavaGroupingByCollectorUnitTest {
     }
 
     @Test
-    public void givenAListOfPosts_whenGroupedByComplexMapPairKeyType_thenGetAMapBetweenPairAndList() {
+    void givenAListOfPosts_whenGroupedByComplexMapPairKeyType_thenGetAMapBetweenPairAndList() {
 
         Map<Pair<BlogPostType, String>, List<BlogPost>> postsPerTypeAndAuthor = posts.stream()
             .collect(groupingBy(post -> new ImmutablePair<>(post.getType(), post.getAuthor())));

core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/map/StreamMapUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.streams;
+package com.baeldung.streams.map;
 
 import org.junit.Before;
 import org.junit.Test;

core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/reduce/StreamReduceUnitTest.java

@@ -1,79 +1,80 @@
-package com.baeldung.reduce;
+package com.baeldung.streams.reduce;
 
-import com.baeldung.reduce.entities.User;
+import static org.assertj.core.api.Assertions.assertThat;
-import com.baeldung.reduce.utilities.NumberUtils;
+
-import org.junit.Test;
+import com.baeldung.streams.reduce.entities.User;
+import com.baeldung.streams.reduce.utilities.NumberUtils;
+
+import org.junit.jupiter.api.Test;
 
 import java.util.Arrays;
 import java.util.List;
 
-import static org.assertj.core.api.Assertions.assertThat;
+class StreamReduceUnitTest {
-
-public class StreamReduceUnitTest {
 
     @Test
-    public void givenIntegerList_whenReduceWithSumAccumulatorLambda_thenCorrect() {
+    void givenIntegerList_whenReduceWithSumAccumulatorLambda_thenCorrect() {
         List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
         int result = numbers.stream().reduce(0, (subtotal, element) -> subtotal + element);
         assertThat(result).isEqualTo(21);
     }
 
     @Test
-    public void givenIntegerList_whenReduceWithSumAccumulatorMethodReference_thenCorrect() {
+    void givenIntegerList_whenReduceWithSumAccumulatorMethodReference_thenCorrect() {
         List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
         int result = numbers.stream().reduce(0, Integer::sum);
         assertThat(result).isEqualTo(21);
     }
 
     @Test
-    public void givenStringList_whenReduceWithConcatenatorAccumulatorLambda_thenCorrect() {
+    void givenStringList_whenReduceWithConcatenatorAccumulatorLambda_thenCorrect() {
         List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
         String result = letters.stream().reduce("", (partialString, element) -> partialString + element);
         assertThat(result).isEqualTo("abcde");
     }
 
     @Test
-    public void givenStringList_whenReduceWithConcatenatorAccumulatorMethodReference_thenCorrect() {
+    void givenStringList_whenReduceWithConcatenatorAccumulatorMethodReference_thenCorrect() {
         List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
         String result = letters.stream().reduce("", String::concat);
         assertThat(result).isEqualTo("abcde");
     }
 
     @Test
-    public void givenStringList_whenReduceWithUppercaseConcatenatorAccumulator_thenCorrect() {
+    void givenStringList_whenReduceWithUppercaseConcatenatorAccumulator_thenCorrect() {
         List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
         String result = letters.stream().reduce("", (partialString, element) -> partialString.toUpperCase() + element.toUpperCase());
         assertThat(result).isEqualTo("ABCDE");
     }
 
     @Test
-    public void givenUserList_whenReduceWithAgeAccumulatorAndSumCombiner_thenCorrect() {
+    void givenUserList_whenReduceWithAgeAccumulatorAndSumCombiner_thenCorrect() {
         List<User> users = Arrays.asList(new User("John", 30), new User("Julie", 35));
         int result = users.stream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
         assertThat(result).isEqualTo(65);
     }
 
     @Test
-    public void givenStringList_whenReduceWithParallelStream_thenCorrect() {
+    void givenStringList_whenReduceWithParallelStream_thenCorrect() {
         List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
         String result = letters.parallelStream().reduce("", String::concat);
         assertThat(result).isEqualTo("abcde");
     }
 
     @Test
-    public void givenNumberUtilsClass_whenCalledDivideListElements_thenCorrect() {
+    void givenNumberUtilsClass_whenCalledDivideListElements_thenCorrect() {
         List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
         assertThat(NumberUtils.divideListElements(numbers, 1)).isEqualTo(21);
     }
 
     @Test
-    public void givenNumberUtilsClass_whenCalledDivideListElementsWithExtractedTryCatchBlock_thenCorrect() {
+    void givenNumberUtilsClass_whenCalledDivideListElementsWithExtractedTryCatchBlock_thenCorrect() {
         List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
         assertThat(NumberUtils.divideListElementsWithExtractedTryCatchBlock(numbers, 1)).isEqualTo(21);
     }
 
     @Test
-    public void givenStream_whneCalleddivideListElementsWithApplyFunctionMethod_thenCorrect() {
+    void givenStream_whneCalleddivideListElementsWithApplyFunctionMethod_thenCorrect() {
         List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
         assertThat(NumberUtils.divideListElementsWithApplyFunctionMethod(numbers, 1)).isEqualTo(21);
     }

core-java-modules/core-java-streams/README.md

@@ -9,7 +9,6 @@ This module contains articles about the Stream API in Java.
 - [Iterable to Stream in Java](https://www.baeldung.com/java-iterable-to-stream)
 - [How to Iterate Over a Stream With Indices](https://www.baeldung.com/java-stream-indices)
 - [Stream Ordering in Java](https://www.baeldung.com/java-stream-ordering)
-- [Java Stream Filter with Lambda Expression](https://www.baeldung.com/java-stream-filter-lambda)
 - [Counting Matches on a Stream Filter](https://www.baeldung.com/java-stream-filter-count)
 - [Summing Numbers with Java Streams](https://www.baeldung.com/java-stream-sum)
 - [How to Find All Getters Returning Null](https://www.baeldung.com/java-getters-returning-null)

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

@@ -29,11 +29,6 @@
             <artifactId>streamex</artifactId>
             <version>${streamex.version}</version>
         </dependency>
-        <dependency>
-            <groupId>com.pivovarit</groupId>
-            <artifactId>throwing-function</artifactId>
-            <version>${throwing-function.version}</version>
-        </dependency>
     </dependencies>
 
     <build>
@@ -62,8 +57,6 @@
         <vavr.version>0.10.4</vavr.version>
         <protonpack.version>1.16</protonpack.version>
         <streamex.version>0.8.1</streamex.version>
-        <throwing-function.version>1.5.1</throwing-function.version>
-
         <maven.compiler.source>17</maven.compiler.source>
         <maven.compiler.target>17</maven.compiler.target>
     </properties>