Merge branch 'eugenp:master' into master

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);
+    }
+}

apache-kafka-2/README.md

@@ -13,3 +13,4 @@ You can build the project from the command line using: *mvn clean install*, or i
 - [Read Data From the Beginning Using Kafka Consumer API](https://www.baeldung.com/java-kafka-consumer-api-read)
 - [Get Partition Count for a Topic in Kafka](https://www.baeldung.com/java-kafka-partition-count-topic)
 - [bootstrap-server in Kafka Configuration](https://www.baeldung.com/java-kafka-bootstrap-server)
+- [Introduction to Apache Kafka](https://www.baeldung.com/apache-kafka)

apache-kafka-2/src/test/java/com/baeldung/kafka/multipletopics/MultipleTopicsLiveTest.java

@@ -0,0 +1,103 @@
+package com.baeldung.kafka.multipletopics;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.time.Duration;
+import java.util.Arrays;
+import java.util.Properties;
+import java.util.concurrent.ExecutionException;
+
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.clients.consumer.KafkaConsumer;
+import org.apache.kafka.clients.producer.KafkaProducer;
+import org.apache.kafka.clients.producer.ProducerConfig;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.apache.kafka.common.serialization.StringSerializer;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.testcontainers.containers.KafkaContainer;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+import org.testcontainers.utility.DockerImageName;
+
+// This live test needs a Docker Daemon running so that a kafka container can be created
+
+@Testcontainers
+public class MultipleTopicsLiveTest {
+
+    private final Logger log = LoggerFactory.getLogger(MultipleTopicsLiveTest.class);
+
+    private static final String CARD_PAYMENTS_TOPIC = "card-payments";
+    private static final String BANK_TRANSFERS_TOPIC = "bank-transfers";
+    private static KafkaProducer<String, String> producer;
+    private static KafkaConsumer<String, String> consumer;
+
+    @Container
+    private static final KafkaContainer KAFKA_CONTAINER = new KafkaContainer(DockerImageName.parse("confluentinc/cp-kafka:latest"));
+
+    @BeforeAll
+    static void setup() {
+        KAFKA_CONTAINER.addExposedPort(9092);
+        producer = new KafkaProducer<>(getProducerProperties());
+        consumer = new KafkaConsumer<>(getConsumerProperties());
+    }
+
+    @AfterAll
+    static void destroy() {
+        KAFKA_CONTAINER.stop();
+    }
+
+    private static Properties getProducerProperties() {
+        Properties producerProperties = new Properties();
+        producerProperties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, KAFKA_CONTAINER.getBootstrapServers());
+        producerProperties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
+        producerProperties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
+        return producerProperties;
+    }
+
+    private static Properties getConsumerProperties() {
+        Properties consumerProperties = new Properties();
+        consumerProperties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, KAFKA_CONTAINER.getBootstrapServers());
+        consumerProperties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
+        consumerProperties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
+        consumerProperties.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
+        consumerProperties.put(ConsumerConfig.GROUP_ID_CONFIG, "payments");
+        return consumerProperties;
+    }
+
+    @Test
+    void whenSendingMessagesOnTwoTopics_thenConsumerReceivesMessages() throws Exception {
+        publishMessages();
+
+        consumer.subscribe(Arrays.asList(CARD_PAYMENTS_TOPIC, BANK_TRANSFERS_TOPIC));
+
+        int eventsProcessed = 0;
+        for (ConsumerRecord<String, String> record : consumer.poll(Duration.ofSeconds(10))) {
+            log.info("Event on topic={}, payload={}", record.topic(), record.value());
+            eventsProcessed++;
+        }
+
+        assertThat(eventsProcessed).isEqualTo(2);
+    }
+
+    private void publishMessages() throws ExecutionException, InterruptedException {
+        ProducerRecord<String, String> cardPayment = new ProducerRecord<>(CARD_PAYMENTS_TOPIC, createCardPayment());
+        producer.send(cardPayment).get();
+
+        ProducerRecord<String, String> bankTransfer = new ProducerRecord<>(BANK_TRANSFERS_TOPIC, createBankTransfer());
+        producer.send(bankTransfer).get();
+    }
+
+    private String createCardPayment() {
+        return "{\"paymentReference\":\"A184028KM0013790\", \"type\":\"card\", \"amount\":\"275\", \"currency\":\"GBP\"}";
+    }
+
+    private String createBankTransfer() {
+        return "{\"paymentReference\":\"19ae2-18mk73-009\", \"type\":\"bank\", \"amount\":\"150\", \"currency\":\"EUR\"}";
+    }
+}

apache-poi-3/README.md

@@ -0,0 +1,3 @@
+## Relevant Articles
+- [How To Convert Excel Data Into List Of Java Objects](https://www.baeldung.com/java-convert-excel-data-into-list)
+- [Expand Columns with Apache POI](https://www.baeldung.com/java-apache-poi-expand-columns)

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

@@ -5,3 +5,4 @@
 - [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;
-        Integer obj_a = 125; // this is autoboxed
-        Assert.assertSame(primitive_a, obj_a);
+        List<Integer> list = new ArrayList<>();
+        list.add(1); // this is autoboxed
+        Assert.assertEquals(list.get(0), Integer.valueOf(1));
     }
 
     @Test

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-21/README.md

@@ -1,2 +1,5 @@
 ## Relevant Articles
 - [Sequenced Collections in Java 21](https://www.baeldung.com/java-21-sequenced-collections)
+- [String Templates in Java 21](https://www.baeldung.com/java-21-string-templates)
+- [Unnamed Classes and Instance Main Methods in Java 21](https://www.baeldung.com/java-21-unnamed-class-instance-main)
+- [Unnamed Patterns and Variables in Java 21](https://www.baeldung.com/java-unnamed-patterns-variables)

core-java-modules/core-java-21/src/main/java/com/baeldung/unnamedclasses/HelloWorld.java

@@ -0,0 +1,3 @@
+void main() {
+    System.out.println("Hello, World!");
+}

core-java-modules/core-java-21/src/main/java/com/baeldung/unnamedclasses/HelloWorldChild.java

@@ -0,0 +1,7 @@
+package com.baeldung.unnamedclasses;
+
+public class HelloWorldChild extends HelloWorldSuper {
+    void main() {
+        System.out.println("Hello, World!");
+    }
+}

core-java-modules/core-java-21/src/main/java/com/baeldung/unnamedclasses/HelloWorldSuper.java

@@ -0,0 +1,7 @@
+package com.baeldung.unnamedclasses;
+
+public class HelloWorldSuper {
+    public static void main(String[] args) {
+        System.out.println("Hello from the superclass");
+    }
+}

core-java-modules/core-java-21/src/main/java/com/baeldung/unnamedclasses/HelloWorldWithMethod.java

@@ -0,0 +1,6 @@
+private String getMessage() {
+    return "Hello, World!";
+}
+void main() {
+    System.out.println(getMessage());
+}

core-java-modules/core-java-9-streams/README.md

@@ -4,3 +4,4 @@ This module contains articles about Java 9 streams
 
 ### Relevant Articles: 
 - [How to Break from Java Stream forEach](https://www.baeldung.com/java-break-stream-foreach)
+- [Creating Stream of Regex Matches](https://www.baeldung.com/java-stream-regex-matches)

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-arrays-guides/README.md

@@ -9,3 +9,4 @@ This module contains complete guides about arrays in Java
 - [Guide to ArrayStoreException](https://www.baeldung.com/java-arraystoreexception)
 - [Creating a Generic Array in Java](https://www.baeldung.com/java-generic-array)
 - [Maximum Size of Java Arrays](https://www.baeldung.com/java-arrays-max-size)
+- [Merge Two Arrays and Remove Duplicates in Java](https://www.baeldung.com/java-merge-two-arrays-delete-duplicates)

core-java-modules/core-java-arrays-operations-advanced-2/README.md

@@ -0,0 +1,2 @@
+## Relevant Articles
+- [Find the Middle Element of an Array in Java](https://www.baeldung.com/java-array-middle-item)

core-java-modules/core-java-arrays-operations-advanced/README.md

@@ -14,4 +14,3 @@ This module contains articles about advanced operations on arrays in Java. They
 - [Slicing Arrays in Java](https://www.baeldung.com/java-slicing-arrays)
 - [Combining Two or More Byte Arrays](https://www.baeldung.com/java-concatenate-byte-arrays)
 - [Calculating the Sum of Two Arrays in Java](https://www.baeldung.com/java-sum-arrays-element-wise)
-- [Find the Middle Element of an Array in Java](https://www.baeldung.com/java-array-middle-item)

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

@@ -5,3 +5,4 @@ This module contains articles about Java Character Class
 ### Relevant Articles: 
 - [Character#isAlphabetic vs. Character#isLetter](https://www.baeldung.com/java-character-isletter-isalphabetic)
 - [Difference Between Java’s “char” and “String”](https://www.baeldung.com/java-char-vs-string)
+- [Increment Character in Java](https://www.baeldung.com/java-char-sequence)

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

@@ -5,4 +5,6 @@
 ### Relevant Articles:
 - [Introduction to Roaring Bitmap](https://www.baeldung.com/java-roaring-bitmap-intro)
 - [Creating Custom Iterator in Java](https://www.baeldung.com/java-creating-custom-iterator)
+- [Difference Between Arrays.sort() and Collections.sort()](https://www.baeldung.com/java-arrays-collections-sort-methods)
+- [Skipping the First Iteration in Java](https://www.baeldung.com/java-skip-first-iteration)
 - More articles: [[<-- prev]](/core-java-modules/core-java-collections-4)

core-java-modules/core-java-collections-array-list-2/README.md

@@ -0,0 +1,6 @@
+## Core Java Collections ArrayList
+
+This module contains articles about the Java ArrayList collection
+
+### Relevant Articles:
+- [Create an ArrayList with Multiple Object Types](https://www.baeldung.com/java-arraylist-multiple-object-types)

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

@@ -0,0 +1,32 @@
+<project
+    xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>core-java-collections-array-list-2</artifactId>
+    <name>core-java-collections-array-list-2</name>
+    <packaging>jar</packaging>
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+    
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>${maven-compiler-plugin.source}</source>
+                    <target>${maven-compiler-plugin.target}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+    
+    <properties>
+        <maven-compiler-plugin.source>17</maven-compiler-plugin.source>
+        <maven-compiler-plugin.target>17</maven-compiler-plugin.target>
+    </properties>
+</project>

core-java-modules/core-java-collections-array-list-2/src/main/java/com/baeldung/list/multipleobjecttypes/AlternativeMultipeTypeList.java

@@ -0,0 +1,51 @@
+package com.baeldung.list.multipleobjecttypes;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.function.Predicate;
+
+public class AlternativeMultipeTypeList {
+
+    public static void main(String[] args) {
+        // List of Parent Class
+        ArrayList<Number> myList = new ArrayList<>();
+        myList.add(1.2);
+        myList.add(2);
+        myList.add(-3.5);
+
+        // List of Interface type
+        ArrayList<Map> diffMapList = new ArrayList<>();
+        diffMapList.add(new HashMap<>());
+        diffMapList.add(new TreeMap<>());
+        diffMapList.add(new LinkedHashMap<>());
+
+        // List of Custom Object
+        ArrayList<CustomObject> objList = new ArrayList<>();
+        objList.add(new CustomObject("String"));
+        objList.add(new CustomObject(2));
+
+        // List via Functional Interface
+        List<Object> dataList = new ArrayList<>();
+
+        Predicate<Object> myPredicate = inputData -> (inputData instanceof String || inputData instanceof Integer);
+
+        UserFunctionalInterface myInterface = (listObj, data) -> {
+            if (myPredicate.test(data))
+                listObj.add(data);
+            else
+                System.out.println("Skipping input as data not allowed for class: " + data.getClass()
+                    .getSimpleName());
+            return listObj;
+        };
+
+        myInterface.addToList(dataList, Integer.valueOf(2));
+        myInterface.addToList(dataList, Double.valueOf(3.33));
+        myInterface.addToList(dataList, "String Value");
+        myInterface.printList(dataList);
+    }
+
+}

core-java-modules/core-java-collections-array-list-2/src/main/java/com/baeldung/list/multipleobjecttypes/CustomObject.java

@@ -0,0 +1,22 @@
+package com.baeldung.list.multipleobjecttypes;
+
+public class CustomObject {
+    String classData;
+    Integer intData;
+
+    CustomObject(String classData) {
+        this.classData = classData;
+    }
+
+    CustomObject(Integer intData) {
+        this.intData = intData;
+    }
+
+    public String getClassData() {
+        return this.classData;
+    }
+
+    public Integer getIntData() {
+        return this.intData;
+    }
+}

core-java-modules/core-java-collections-array-list-2/src/main/java/com/baeldung/list/multipleobjecttypes/MultipleObjectTypeArrayList.java

@@ -0,0 +1,40 @@
+package com.baeldung.list.multipleobjecttypes;
+
+import java.math.BigInteger;
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class MultipleObjectTypeArrayList {
+
+    public static void main(String[] args) {
+
+        ArrayList<Object> multiTypeList = new ArrayList<>();
+
+        multiTypeList.add(Integer.valueOf(10));
+        multiTypeList.add(Double.valueOf(11.5));
+        multiTypeList.add("String Data");
+        multiTypeList.add(Arrays.asList(1, 2, 3));
+        multiTypeList.add(new CustomObject("Class Data"));
+        multiTypeList.add(BigInteger.valueOf(123456789));
+        multiTypeList.add(LocalDate.of(2023, 9, 19));
+
+        for (Object dataObj : multiTypeList) {
+            if (dataObj instanceof Integer intData)
+                System.out.println("Integer Data : " + intData);
+            else if (dataObj instanceof Double doubleData)
+                System.out.println("Double Data : " + doubleData);
+            else if (dataObj instanceof String stringData)
+                System.out.println("String Data : " + stringData);
+            else if (dataObj instanceof List<?> intList)
+                System.out.println("List Data : " + intList);
+            else if (dataObj instanceof CustomObject customObj)
+                System.out.println("CustomObject Data : " + customObj.getClassData());
+            else if (dataObj instanceof BigInteger bigIntData)
+                System.out.println("BigInteger Data : " + bigIntData);
+            else if (dataObj instanceof LocalDate localDate)
+                System.out.println("LocalDate Data : " + localDate.toString());
+        }
+    }
+}

core-java-modules/core-java-collections-array-list-2/src/main/java/com/baeldung/list/multipleobjecttypes/UserFunctionalInterface.java

@@ -0,0 +1,18 @@
+package com.baeldung.list.multipleobjecttypes;
+
+import java.util.List;
+
+@FunctionalInterface
+public interface UserFunctionalInterface {
+
+    List<Object> addToList(List<Object> list, Object data);
+
+    default void printList(List<Object> dataList) {
+        for (Object data : dataList) {
+            if (data instanceof String stringData)
+                System.out.println("String Data: " + stringData);
+            if (data instanceof Integer intData)
+                System.out.println("Integer Data: " + intData);
+        }
+    }
+}

core-java-modules/core-java-collections-conversions-3/README.md

@@ -3,3 +3,4 @@
 This module contains articles about conversions among Collection types in Java.
 
 ### Relevant Articles:
+- [Converting HashMap Values to an ArrayList in Java](https://www.baeldung.com/java-hashmap-arraylist)

core-java-modules/core-java-collections-list-6/README.md

@@ -0,0 +1,2 @@
+## Relevant Articles
+- [Check if a List Contains a String Element While Ignoring Case](https://www.baeldung.com/java-list-search-case-insensitive)

core-java-modules/core-java-collections-maps-6/src/test/com/baeldung/objecttomap/ObjectToMapUnitTest.java

@@ -1,76 +0,0 @@
-package java.com.baeldung.objecttomap;
-import com.google.gson.Gson;
-import org.junit.Assert;
-import org.junit.Test;
-import wiremock.com.fasterxml.jackson.core.type.TypeReference;
-import wiremock.com.fasterxml.jackson.databind.ObjectMapper;
-import wiremock.com.google.common.reflect.TypeToken;
-import java.lang.reflect.Field;
-import java.util.HashMap;
-import java.util.Map;
-
-public class ObjectToMapUnitTest {
-    Employee employee = new Employee("John", 3000.0);
-
-    @Test
-    public void givenJavaObject_whenUsingReflection_thenConvertToMap() throws IllegalAccessException {
-        Map<String, Object> map = convertUsingReflection(employee);
-        Assert.assertEquals(employee.getName(), map.get("name"));
-        Assert.assertEquals(employee.getSalary(), map.get("salary"));
-    }
-
-    private Map<String, Object> convertUsingReflection(Object object) throws IllegalAccessException {
-        Map<String, Object> map = new HashMap<>();
-        Field[] fields = object.getClass().getDeclaredFields();
-
-        for (Field field : fields) {
-            field.setAccessible(true);
-            map.put(field.getName(), field.get(object));
-        }
-
-        return map;
-    }
-
-    @Test
-    public void givenJavaObject_whenUsingJackson_thenConvertToMap() {
-        ObjectMapper objectMapper = new ObjectMapper();
-        Map<String, Object> map = objectMapper.convertValue(employee, new TypeReference<Map<String, Object>>() {});
-        Assert.assertEquals(employee.getName(), map.get("name"));
-        Assert.assertEquals(employee.getSalary(), map.get("salary"));
-    }
-
-    @Test
-    public void givenJavaObject_whenUsingGson_thenConvertToMap() {
-        Gson gson = new Gson();
-        String json = gson.toJson(employee);
-        Map<String, Object> map = gson.fromJson(json, new TypeToken<Map<String, Object>>() {}.getType());
-        Assert.assertEquals(employee.getName(), map.get("name"));
-        Assert.assertEquals(employee.getSalary(), map.get("salary"));
-    }
-
-    private static class Employee {
-        private String name;
-        private Double salary;
-
-        public Employee(String name, Double salary) {
-            this.name = name;
-            this.salary = salary;
-        }
-
-        public String getName() {
-            return name;
-        }
-
-        public void setName(String name) {
-            this.name = name;
-        }
-
-        public Double getSalary() {
-            return salary;
-        }
-
-        public void setSalary(Double age) {
-            this.salary = salary;
-        }
-    }
-}

core-java-modules/core-java-collections-maps-6/src/test/java/com/baeldung/objecttomap/ObjectToMapUnitTest.java

@@ -0,0 +1,128 @@
+package com.baeldung.objecttomap;
+
+import static org.junit.Assert.assertEquals;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.reflect.TypeToken;
+import com.google.gson.Gson;
+import org.junit.Test;
+import java.lang.reflect.Field;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.SortedMap;
+import java.util.TreeMap;
+import java.util.stream.Collectors;
+
+public class ObjectToMapUnitTest {
+    Employee employee = new Employee("John", 3000.0);
+
+    @Test
+    public void givenJavaObject_whenUsingReflection_thenConvertToMap() throws IllegalAccessException {
+        Map<String, Object> map = convertUsingReflection(employee);
+        assertEquals(employee.getName(), map.get("name"));
+        assertEquals(employee.getSalary(), map.get("salary"));
+    }
+
+    private Map<String, Object> convertUsingReflection(Object object) throws IllegalAccessException {
+        Map<String, Object> map = new HashMap<>();
+        Field[] fields = object.getClass().getDeclaredFields();
+
+        for (Field field : fields) {
+            field.setAccessible(true);
+            map.put(field.getName(), field.get(object));
+        }
+
+        return map;
+    }
+
+    @Test
+    public void givenJavaObject_whenUsingJackson_thenConvertToMap() {
+        ObjectMapper objectMapper = new ObjectMapper();
+        Map<String, Object> map = objectMapper.convertValue(employee, new TypeReference<Map<String, Object>>() {});
+        assertEquals(employee.getName(), map.get("name"));
+        assertEquals(employee.getSalary(), map.get("salary"));
+    }
+
+    @Test
+    public void givenJavaObject_whenUsingGson_thenConvertToMap() {
+        Gson gson = new Gson();
+        String json = gson.toJson(employee);
+        Map<String, Object> map = gson.fromJson(json, new TypeToken<Map<String, Object>>() {}.getType());
+        assertEquals(employee.getName(), map.get("name"));
+        assertEquals(employee.getSalary(), map.get("salary"));
+    }
+
+    @Test
+    public void given_UnsortedMap_whenSortingByValueDescending_thenValuesAreInDescendingOrder() {
+        Map<String, Integer> unsortedMap = new HashMap<>();
+        unsortedMap.put("one", 1);
+        unsortedMap.put("three", 3);
+        unsortedMap.put("five", 5);
+        unsortedMap.put("two", 2);
+        unsortedMap.put("four", 4);
+
+        Map<String, Integer> sortedMap = sortMapByValueDescending(unsortedMap);
+
+        assertEquals(5, sortedMap.size());
+        final Iterator<Integer> iterator = sortedMap.values().iterator();
+        assertEquals(5, (int) iterator.next());
+        assertEquals(4, (int) iterator.next());
+        assertEquals(3, (int) iterator.next());
+        assertEquals(2, (int) iterator.next());
+        assertEquals(1, (int) iterator.next());
+    }
+
+    @Test
+    public void given_UnsortedMap_whenUsingTreeMap_thenKeysAreInDescendingOrder() {
+        SortedMap<String, Integer> treeMap = new TreeMap<>(Comparator.reverseOrder());
+        treeMap.put("one", 1);
+        treeMap.put("three", 3);
+        treeMap.put("five", 5);
+        treeMap.put("two", 2);
+        treeMap.put("four", 4);
+
+        assertEquals(5, treeMap.size());
+        final Iterator<String> iterator = treeMap.keySet().iterator();
+        assertEquals("two", iterator.next());
+        assertEquals("three", iterator.next());
+        assertEquals("one", iterator.next());
+        assertEquals("four", iterator.next());
+        assertEquals("five", iterator.next());
+    }
+
+    private static class Employee {
+        private String name;
+        private Double salary;
+
+        public Employee(String name, Double salary) {
+            this.name = name;
+            this.salary = salary;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+
+        public Double getSalary() {
+            return salary;
+        }
+
+        public void setSalary(Double age) {
+            this.salary = salary;
+        }
+    }
+
+    public static <K, V extends Comparable<? super V>> Map<K, V> sortMapByValueDescending(Map<K, V> map) {
+        return map.entrySet().stream()
+                .sorted(Map.Entry.<K, V>comparingByValue().reversed())
+                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));
+    }
+}

core-java-modules/core-java-collections-maps-7/README.md

@@ -0,0 +1 @@
+## Relevant Articles

core-java-modules/core-java-collections-maps-7/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-collections-maps-7</artifactId>
+    <name>core-java-collections-maps-7</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <artifactId>core-java-modules</artifactId>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+    <properties>
+        <spring.version>5.2.5.RELEASE</spring.version>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.12.4</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>1.36</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>2.8.9</version>
+        </dependency>
+        <dependency>
+            <groupId>org.json</groupId>
+            <artifactId>json</artifactId>
+            <version>20230227</version>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.8.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.8.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.8.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.1</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+</project>

core-java-modules/core-java-collections-maps-7/src/main/java/com/baeldung/map/ConvertHashMapStringToHashMapObjectUsingtoString.java

@@ -0,0 +1,60 @@
+package com.baeldung.map;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ConvertHashMapStringToHashMapObjectUsingtoString {
+    public String name;
+    public int age;
+
+    public ConvertHashMapStringToHashMapObjectUsingtoString(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public static ConvertHashMapStringToHashMapObjectUsingtoString deserializeCustomObject(String valueString) {
+        if (valueString.startsWith("{") && valueString.endsWith("}")) {
+            valueString = valueString.substring(1, valueString.length() - 1);
+            String[] parts = valueString.split(",");
+            String name = null;
+            int age = -1;
+            for (String part : parts) {
+                String[] keyValue = part.split("=");
+                if (keyValue.length == 2) {
+                    String key = keyValue[0].trim();
+                    String val = keyValue[1].trim();
+                    if (key.equals("name")) {
+                        name = val;
+                    } else if (key.equals("age")) {
+                        age = Integer.parseInt(val);
+                    }
+                }
+            }
+            if (name != null && age >= 0) {
+                return new ConvertHashMapStringToHashMapObjectUsingtoString(name, age);
+            }
+        }
+        return new ConvertHashMapStringToHashMapObjectUsingtoString("", -1);
+    }
+
+    public static void main(String[] args) {
+        String hashMapString = "{key1={name=John, age=30}, key2={name=Alice, age=25}}";
+        String keyValuePairs = hashMapString.replaceAll("[{}\\s]", "");
+        String[] pairs = keyValuePairs.split(",");
+        Map<String, ConvertHashMapStringToHashMapObjectUsingtoString> actualHashMap = new HashMap<>();
+        for (String pair : pairs) {
+            String[] keyValue = pair.split("=");
+            if (keyValue.length == 2) {
+                String key = keyValue[0];
+                ConvertHashMapStringToHashMapObjectUsingtoString value = deserializeCustomObject(keyValue[1]);
+                actualHashMap.put(key, value);
+            }
+        }
+        System.out.println(actualHashMap);
+    }
+
+    @Override
+    public String toString() {
+        return "{name=" + name + ", age=" + age + "}";
+    }
+}

core-java-modules/core-java-collections-maps-7/src/test/java/com/baeldung/map/ConvertHashMapStringToHashMapObjectUsingtoStringUnitTest.java

@@ -0,0 +1,31 @@
+package com.baeldung.map;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ConvertHashMapStringToHashMapObjectUsingtoStringUnitTest {
+
+    @Test
+    void givenValidCustomObject_whenSerializing_thenSerializedStringIsCorrect() {
+        ConvertHashMapStringToHashMapObjectUsingtoString customObject = new ConvertHashMapStringToHashMapObjectUsingtoString("John", 30);
+        String expectedSerializedString = "{name=John, age=30}";
+        assertEquals(expectedSerializedString, customObject.toString());
+    }
+
+    @Test
+    void givenValidSerializedString_whenDeserializing_thenCustomObjectIsCorrect() {
+        String serializedString = "{name=Alice, age=25}";
+        ConvertHashMapStringToHashMapObjectUsingtoString customObject = ConvertHashMapStringToHashMapObjectUsingtoString.deserializeCustomObject(serializedString);
+        assertEquals("Alice", customObject.name);
+        assertEquals(25, customObject.age);
+    }
+
+    @Test
+    void givenInvalidSerializedString_whenDeserializing_thenDefaultCustomObjectIsCreated() {
+        String invalidSerializedString = "{invalidString}";
+        ConvertHashMapStringToHashMapObjectUsingtoString customObject = ConvertHashMapStringToHashMapObjectUsingtoString.deserializeCustomObject(invalidSerializedString);
+        assertEquals("", customObject.name);
+        assertEquals(-1, customObject.age);
+    }
+}

core-java-modules/core-java-datetime-conversion/src/test/java/com/baeldung/epochtolocaldate/EpochTimeToLocalDateTimeConverterUnitTest.java

@@ -12,10 +12,10 @@ public class EpochTimeToLocalDateTimeConverterUnitTest {
     @Test
     public void testConvertEpochTimeToLocalDateTime() {
         long epochTimeMillis = 1624962431000L; // Example epoch time in milliseconds
-        LocalDateTime expectedDateTime = LocalDateTime.of(2021, 6, 29, 12, 13, 51);
+        LocalDateTime expectedDateTime = LocalDateTime.of(2021, 6, 29, 10, 27, 11);
 
         Instant instant = Instant.ofEpochMilli(epochTimeMillis);
-        ZoneId zoneId = ZoneId.systemDefault();
+        ZoneId zoneId = ZoneId.of("UTC");
         LocalDateTime actualDateTime = instant.atZone(zoneId).toLocalDateTime();
 
         assertEquals(expectedDateTime, actualDateTime);

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

@@ -3,4 +3,4 @@
 ### Relevant Articles: 
 
 - [Introduction to Javadoc](http://www.baeldung.com/javadoc)
-
+- [Code Snippets in Java API Documentation](https://www.baeldung.com/java-doc-code-snippets)

core-java-modules/core-java-io-5/.gitignore

@@ -0,0 +1,2 @@
+test-link*
+0.*

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

@@ -0,0 +1,8 @@
+## Core Java IO
+
+This module contains articles about core Java input and output (IO)
+
+### Relevant Articles: 
+- [Get File Extension From MIME Type in Java](https://www.baeldung.com/java-mime-type-file-extension)
+- [[<-- Prev]](/core-java-modules/core-java-io-4)
+

core-java-modules/core-java-io-5/pom.xml

@@ -0,0 +1,66 @@
+<?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-io-5</artifactId>
+    <name>core-java-io-5</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>
+        <!-- Mime Type Resolution Libraries -->
+        <dependency>
+            <groupId>org.apache.tika</groupId>
+            <artifactId>tika-core</artifactId>
+            <version>${tika.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>net.sf.jmimemagic</groupId>
+            <artifactId>jmimemagic</artifactId>
+            <version>${jmime-magic.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.jodd</groupId>
+            <artifactId>jodd-util</artifactId>
+            <version>${jodd-util.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.j256.simplemagic</groupId>
+            <artifactId>simplemagic</artifactId>
+            <version>${simplemagic.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-io-5</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+        <plugins>
+            <plugin>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>11</source>
+                    <target>11</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <!-- Mime Type Libraries -->
+        <tika.version>2.8.0</tika.version>
+        <jmime-magic.version>0.1.5</jmime-magic.version>
+        <jodd-util.version>6.2.1</jodd-util.version>
+        <simplemagic.version>1.17</simplemagic.version>
+    </properties>
+</project>

core-java-modules/core-java-io-5/src/test/java/com/baeldung/extension/ExtensionFromMimeTypeUnitTest.java

@@ -11,10 +11,8 @@ import java.util.Map;
 import java.util.Set;
 
 import org.apache.tika.mime.MimeTypeException;
-
-import org.junit.Test;
-
 import com.j256.simplemagic.ContentType;
+import org.junit.Test;
 
 public class ExtensionFromMimeTypeUnitTest {
     private static final String IMAGE_JPEG_MIME_TYPE = "image/jpeg";
@@ -37,14 +35,14 @@ public class ExtensionFromMimeTypeUnitTest {
     }
 
     @Test
-    public void whenUsingMimetypesFileTypeMap_thenGetFileExtension() {
+    public void whenUsingSimpleMagic_thenGetFileExtension() {
         List<String> expectedExtensions = Arrays.asList("jpeg", "jpg", "jpe");
         String[] detectedExtensions = ContentType.fromMimeType(IMAGE_JPEG_MIME_TYPE).getFileExtensions();
         assertThat(detectedExtensions).containsExactlyElementsOf(expectedExtensions);
     }
 
     @Test
-    public void whenUsingCustomLogic_thenGetFileExtension() {
+    public void whenUsingCustomMap_thenGetFileExtension() {
         Map<String, Set<String>> mimeExtensionsMap = new HashMap<>();
         List<String> expectedExtensions = Arrays.asList(".jpg", ".jpe", ".jpeg");
         addMimeExtensions(mimeExtensionsMap, "image/jpeg", ".jpg");

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-io-apis-2/README.md

@@ -7,3 +7,4 @@ This module contains articles about core Java input/output(IO) APIs.
 - [Get the Desktop Path in Java](https://www.baeldung.com/java-desktop-path)
 - [Check if a File Is Empty in Java](https://www.baeldung.com/java-check-file-empty)
 - [Converting Relative to Absolute Paths in Java](https://www.baeldung.com/java-from-relative-to-absolute-paths)
+- [Detect EOF in Java](https://www.baeldung.com/java-file-detect-end-of-file)

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

@@ -43,17 +43,6 @@
             <version>${angus-activation.version}</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>org.jodd</groupId>
-            <artifactId>jodd-util</artifactId>
-            <version>${jodd-util.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>com.j256.simplemagic</groupId>
-            <artifactId>simplemagic</artifactId>
-            <version>${simplemagic.version}</version>
-        </dependency>
-
     </dependencies>
 
     <build>
@@ -153,8 +142,6 @@
         <fscontext.version>4.4.2</fscontext.version>
         <jakarta-activation-api.version>2.1.2</jakarta-activation-api.version>
         <angus-activation.version>2.0.1</angus-activation.version>
-        <jodd-util.version>6.2.1</jodd-util.version>
-        <simplemagic.version>1.17</simplemagic.version>
     </properties>
 
 </project>

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

@@ -4,4 +4,5 @@
 - [Integer.class vs Integer.TYPE vs int.class](https://www.baeldung.com/java-integer-class-vs-type-vs-int)
 - [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)
 - More articles: [[<-- prev]](../core-java-numbers-5)

core-java-modules/core-java-numbers-6/pom.xml

@@ -25,8 +25,12 @@
             <version>${commons-codec}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
     </dependencies>
-
     <build>
         <finalName>core-java-numbers-6</finalName>
         <resources>
@@ -39,5 +43,6 @@
 
     <properties>
         <commons-codec>1.15</commons-codec>
+        <guava.version>32.1.2-jre</guava.version>
     </properties>
 </project>

core-java-modules/core-java-numbers-6/src/main/java/com/baeldung/bigintegerroot/BenchmarkRunner.java

@@ -0,0 +1,8 @@
+package com.baeldung.bigintegerroot;
+
+public class BenchmarkRunner {
+    public static void main(String[] args) throws Exception {
+        org.openjdk.jmh.Main.main(args);
+    }
+}
+

core-java-modules/core-java-numbers-6/src/main/java/com/baeldung/bigintegerroot/BigIntegerHolder.java

@@ -0,0 +1,10 @@
+package com.baeldung.bigintegerroot;
+
+public class BigIntegerHolder {
+
+    private BigIntegerHolder() {
+    }
+    public static final String BIG_NUMBER = "179769313000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000";
+    public static final String VERY_BIG_NUMBER = "32473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834";
+    public static final String INSANELY_BIG_NUMBER = "3247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834324739274923749279342847923749237492374987230480128343247392749237492793428479237492374923749872304801283432473927492374927934284792374923749237498723048012834";
+}

core-java-modules/core-java-numbers-6/src/main/java/com/baeldung/bigintegerroot/BigIntegerSquareRootBenchmark.java

@@ -0,0 +1,60 @@
+package com.baeldung.bigintegerroot;
+
+import static com.baeldung.bigintegerroot.BigIntegerHolder.*;
+
+import com.baeldung.bigintegerroot.algorithms.Newton;
+import com.baeldung.bigintegerroot.algorithms.NewtonPlus;
+import com.google.common.math.BigIntegerMath;
+import java.math.BigInteger;
+import java.math.RoundingMode;
+import java.util.concurrent.TimeUnit;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+@Warmup(iterations = 1)
+@Measurement(iterations = 1, time = 1, timeUnit = TimeUnit.MINUTES)
+@Fork(1)
+@State(Scope.Benchmark)
+public class BigIntegerSquareRootBenchmark {
+
+    @Param({BIG_NUMBER, VERY_BIG_NUMBER, INSANELY_BIG_NUMBER})
+    public String number;
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    public void calculateRootWithJava(Blackhole blackhole) {
+        final BigInteger integer = new BigInteger(number);
+        final BigInteger root = integer.sqrt();
+        blackhole.consume(root);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    public void calculateRootWithGuava(Blackhole blackhole) {
+        final BigInteger integer = new BigInteger(number);
+        final BigInteger root = BigIntegerMath.sqrt(integer, RoundingMode.DOWN);
+        blackhole.consume(root);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    public void calculateRootWithNewtonPlus(Blackhole blackhole) {
+        final BigInteger integer = new BigInteger(number);
+        final BigInteger root = NewtonPlus.sqrt(integer);
+        blackhole.consume(root);
+    }
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    public void calculateRootWithNewton(Blackhole blackhole) {
+        final BigInteger integer = new BigInteger(number);
+        final BigInteger root = Newton.sqrt(integer);
+        blackhole.consume(root);
+    }
+}

core-java-modules/core-java-numbers-6/src/main/java/com/baeldung/bigintegerroot/algorithms/Newton.java

@@ -0,0 +1,29 @@
+package com.baeldung.bigintegerroot.algorithms;
+
+import java.math.BigInteger;
+
+public class Newton {
+
+    private Newton() {
+    }
+
+    public static BigInteger sqrt(BigInteger n) {
+        // Initial approximation
+        BigInteger x = n.divide(BigInteger.TWO);
+
+        // Tolerance level (small positive integer)
+        BigInteger tolerance = BigInteger.ONE;
+
+        while (true) {
+            // x_new = 0.5 * (x + n / x)
+            BigInteger xNew = x.add(n.divide(x)).divide(BigInteger.TWO);
+
+            // Check for convergence within tolerance
+            if (x.subtract(xNew).abs().compareTo(tolerance) <= 0) {
+                return xNew;
+            }
+
+            x = xNew;
+        }
+    }
+}

core-java-modules/core-java-numbers-6/src/main/java/com/baeldung/bigintegerroot/algorithms/NewtonPlus.java

@@ -0,0 +1,108 @@
+package com.baeldung.bigintegerroot.algorithms;
+
+import java.math.BigInteger;
+
+public class NewtonPlus {
+
+    private NewtonPlus() {
+    }
+
+    // A fast square root by Ryan Scott White.
+    public static BigInteger sqrt(BigInteger x) {
+        if (x.compareTo(BigInteger.valueOf(144838757784765629L)) < 0) {
+            long xAsLong = x.longValue();
+            long vInt = (long)Math.sqrt(xAsLong);
+            if (vInt * vInt > xAsLong)
+                vInt--;
+            return BigInteger.valueOf(vInt); }
+
+        double xAsDub = x.doubleValue();
+        BigInteger val;
+        if (xAsDub < 2.1267e37) // 2.12e37 largest here
+        // since sqrt(long.max*long.max) > long.max
+        {
+            long vInt = (long)Math.sqrt(xAsDub);
+            val = BigInteger.valueOf
+                ((vInt + x.divide(BigInteger.valueOf(vInt)).longValue()) >> 1);
+        }
+        else if (xAsDub < 4.3322e127) {
+            // Convert a double to a BigInteger
+            long bits = Double.doubleToLongBits(Math.sqrt(xAsDub));
+            int exp = ((int) (bits >> 52) & 0x7ff) - 1075;
+            val = BigInteger.valueOf((bits & ((1L << 52)) - 1) | (1L << 52)).shiftLeft(exp);
+
+            val = x.divide(val).add(val).shiftRight(1);
+            if (xAsDub > 2e63) {
+                val = x.divide(val).add(val).shiftRight(1); }
+        }
+        else // handle large numbers over 4.3322e127
+        {
+            int xLen = x.bitLength();
+            int wantedPrecision = ((xLen + 1) / 2);
+            int xLenMod = xLen + (xLen & 1) + 1;
+
+            //////// Do the first Sqrt on Hardware ////////
+            long tempX = x.shiftRight(xLenMod - 63).longValue();
+            double tempSqrt1 = Math.sqrt(tempX);
+            long valLong = Double.doubleToLongBits(tempSqrt1) & 0x1fffffffffffffL;
+
+            if (valLong == 0)
+                valLong = 1L << 53;
+
+            //////// Classic Newton Iterations ////////
+            val = BigInteger.valueOf(valLong).shiftLeft(53 - 1)
+                .add((x.shiftRight(xLenMod -
+                                   (3 * 53))).divide(BigInteger.valueOf(valLong)));
+
+            int size = 106;
+            for (; size < 256; size <<= 1) {
+                val = val.shiftLeft(size - 1).add(x.shiftRight
+                    (xLenMod - (3*size)).divide(val));}
+
+            if (xAsDub > 4e254) { // 4e254 = 1<<845.77
+                int numOfNewtonSteps = 31 -
+                                       Integer.numberOfLeadingZeros(wantedPrecision / size)+1;
+
+                ////// Apply Starting Size ////////
+                int wantedSize = (wantedPrecision >> numOfNewtonSteps) + 2;
+                int needToShiftBy = size - wantedSize;
+                val = val.shiftRight(needToShiftBy);
+
+                size = wantedSize;
+                do {
+                    //////// Newton Plus Iteration ////////
+                    int shiftX = xLenMod - (3 * size);
+                    BigInteger valSqrd = val.multiply(val).shiftLeft(size - 1);
+                    BigInteger valSU = x.shiftRight(shiftX).subtract(valSqrd);
+                    val = val.shiftLeft(size).add(valSU.divide(val));
+                    size *= 2;
+                } while (size < wantedPrecision);
+            }
+            val = val.shiftRight(size - wantedPrecision);
+        }
+
+        // Detect a round ups. This function can be further optimized - see article.
+        // For a ~7% speed bump the following line can be removed but round-ups will occur.
+        if (val.multiply(val).compareTo(x) > 0)
+            val = val.subtract(BigInteger.ONE);
+
+        // Enabling the below will guarantee an error is stopped for larger numbers.
+        // Note: As of this writing, there are no known errors.
+        BigInteger tmp = val.multiply(val);
+        if (tmp.compareTo(x) > 0) {
+            System.out.println("val^2(" + val.multiply(val).toString()
+                               + ") ≥ x(" + x.toString()+")");
+            System.console().readLine();
+            //throw new Exception("Sqrt function had internal error - value too high");
+        }
+        if (tmp.add(val.shiftLeft(1)).add(BigInteger.ONE).compareTo(x) <= 0) {
+            System.out.println("(val+1)^2("
+                               + val.add(BigInteger.ONE).multiply(val.add(BigInteger.ONE)).toString()
+                               + ") ≥ x(" + x.toString() + ")");
+            System.console().readLine();
+            //throw new Exception("Sqrt function had internal error - value too low");
+        }
+
+        return val;
+    }
+}

core-java-modules/core-java-numbers-6/src/test/java/com/baeldung/bigintegerroot/BigIntegerSquareRootUnitTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.bigintegerroot;
+
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.baeldung.bigintegerroot.algorithms.Newton;
+import com.baeldung.bigintegerroot.algorithms.NewtonPlus;
+import com.google.common.math.BigIntegerMath;
+import java.math.BigInteger;
+import java.math.RoundingMode;
+import java.util.stream.Stream;
+import org.apache.commons.math3.util.Pair;
+import org.junit.jupiter.api.condition.EnabledForJreRange;
+import org.junit.jupiter.api.condition.JRE;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class BigIntegerSquareRootUnitTest {
+
+    @ParameterizedTest
+    @ValueSource(strings = {
+        BigIntegerHolder.BIG_NUMBER,
+        BigIntegerHolder.VERY_BIG_NUMBER,
+        BigIntegerHolder.VERY_BIG_NUMBER
+    })
+    void squareRootTest(String number) {
+        final BigInteger bigInteger = new BigInteger(number);
+        final BigInteger javaRoot = bigInteger.sqrt();
+        final BigInteger guavaRoot = BigIntegerMath.sqrt(bigInteger, RoundingMode.DOWN);
+        final BigInteger newtonRoot = Newton.sqrt(bigInteger);
+        final BigInteger newtonPlusRoot = NewtonPlus.sqrt(bigInteger);
+
+        assertTrue(Stream.of(
+            new Pair<>(javaRoot, guavaRoot),
+            new Pair<>(guavaRoot, newtonRoot),
+            new Pair<>(newtonRoot, newtonPlusRoot)
+        ).allMatch(pair -> pair.getFirst().equals(pair.getSecond())));
+    }
+}

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/pom.xml

@@ -18,6 +18,18 @@
             <artifactId>commons-lang3</artifactId>
             <version>${commons-lang3.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.testng</groupId>
+            <artifactId>testng</artifactId>
+            <version>RELEASE</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.2</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

core-java-modules/core-java-numbers-conversions/src/main/java/com/baeldung/floatdoubleconversions/FloatAndDoubleConversions.java

@@ -0,0 +1,15 @@
+package com.baeldung.floatdoubleconversions;
+
+public class FloatAndDoubleConversions {
+    public static void main(String args[]){
+        float vatRate = 14.432511f;
+        System.out.println("vatRate:"+vatRate);
+        Float localTaxRate = 20.12434f;
+        System.out.println("localTaxRate:"+localTaxRate);
+
+        double shootingAverage = 56.00000000000001;
+        System.out.println("shootingAverage:"+shootingAverage);
+        Double assistAverage = 81.123000000045;
+        System.out.println("assistAverage:"+assistAverage);
+    }
+}

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

@@ -0,0 +1,29 @@
+package com.baeldung.floatdoubleconversions;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class FloatDoubleConversionsTest {
+
+    @Test
+    public void whenDoubleType_thenFloatTypeSuccess(){
+        double interestRatesYearly = 13.333333333333334;
+        float interest = (float) interestRatesYearly;
+        Assert.assertEquals(13.333333f, interest, 0.000004f);
+
+        Double monthlyRates = 2.111111111111112;
+        float rates = monthlyRates.floatValue();
+        Assert.assertEquals(2.1111112f, rates, 0.00000013);
+    }
+    @Test
+    public void whenFloatType_thenDoubleTypeSuccess(){
+        float gradeAverage =2.05f;
+        double average = gradeAverage;
+        Assert.assertEquals(2.05, average, 0.06);
+
+        Float monthlyRates = 2.1111112f;
+        Double rates = monthlyRates.doubleValue();
+        Assert.assertEquals(2.11111112, rates, 0.0000002);//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-os/README.md

@@ -14,5 +14,6 @@ This module contains articles about working with the operating system (OS) in Ja
 - [How to Run a Shell Command in Java](http://www.baeldung.com/run-shell-command-in-java)
 - [Taking Screenshots Using Java](https://www.baeldung.com/java-taking-screenshots)
 - [Java Sound API – Capturing Microphone](https://www.baeldung.com/java-sound-api-capture-mic)
+- [How to Detect the Username Using Java](https://www.baeldung.com/java-get-username)
 
 This module uses Java 9, so make sure to have the JDK 9 installed to run it.

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

@@ -9,4 +9,5 @@
 - [Regular Expression: \z vs \Z Anchors in Java](https://www.baeldung.com/java-regular-expression-z-vs-z-anchors)
 - [Extract Text Between Square Brackets](https://www.baeldung.com/java-get-content-between-square-brackets)
 - [Get the Indexes of Regex Pattern Matches in Java](https://www.baeldung.com/java-indexes-regex-pattern-matches)
+- [Check if a String is Strictly Alphanumeric With Java](https://www.baeldung.com/java-check-string-contains-only-letters-numbers)
 - More articles: [[<-- prev]](/core-java-modules/core-java-regex)

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(
-              new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256"});
-            ((SSLSocket) connection).setEnabledProtocols(
-              new String[] { "TLSv1.2"});
+            ((SSLSocket) connection).setEnabledCipherSuites(new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256" });
+            ((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(
-              new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256"});
-            ((SSLServerSocket) listener).setEnabledProtocols(
-              new String[] { "TLSv1.2"});
+            ((SSLServerSocket) listener).setEnabledCipherSuites(new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256" });
+            ((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-5/pom.xml

@@ -43,6 +43,11 @@
             <artifactId>vavr</artifactId>
             <version>${vavr.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -72,6 +77,7 @@
         <maven.compiler.source>12</maven.compiler.source>
         <maven.compiler.target>12</maven.compiler.target>
         <vavr.version>0.10.2</vavr.version>
+        <guava.version>32.1.2-jre</guava.version>
     </properties>
 
 </project>

core-java-modules/core-java-streams-5/src/main/java/com/baeldung/streams/partitioning/PartitionStream.java

@@ -0,0 +1,90 @@
+package com.baeldung.streams.partitioning;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.BiConsumer;
+import java.util.function.BinaryOperator;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collector;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+import com.google.common.collect.Iterables;
+
+public class PartitionStream {
+
+    public static <T> Stream<List<T>> partitionList(List<T> source, int batchSize) {
+        if (batchSize <= 0) {
+            throw new IllegalArgumentException(String.format("Expected the batchSize to be greater than ZERO, actual value was: %s", batchSize));
+        }
+        if (source.isEmpty()) {
+            return Stream.empty();
+        }
+        int nrOfFullBatches = (source.size() - 1) / batchSize;
+        return IntStream.rangeClosed(0, nrOfFullBatches)
+          .mapToObj(batch -> {
+              int startIndex = batch * batchSize;
+              int endIndex = (batch == nrOfFullBatches) ? source.size() : (batch + 1) * batchSize;
+              return source.subList(startIndex, endIndex);
+          });
+    }
+
+    public static <T> Iterable<List<T>> partitionUsingGuava(Stream<T> source, int batchSize) {
+        return Iterables.partition(source::iterator, batchSize);
+    }
+
+    public static <T> List<List<T>> partitionStream(Stream<T> source, int batchSize) {
+        return source.collect(partitionBySize(batchSize, Collectors.toList()));
+    }
+
+    public static <T, A, R> Collector<T, ?, R> partitionBySize(int batchSize, Collector<List<T>, A, R> downstream) {
+        Supplier<Accumulator<T, A>> supplier = () -> new Accumulator<>(
+          batchSize,
+          downstream.supplier().get(),
+          downstream.accumulator()::accept
+        );
+
+        BiConsumer<Accumulator<T, A>, T> accumulator = (acc, value) -> acc.add(value);
+
+        BinaryOperator<Accumulator<T, A>> combiner = (acc1, acc2) -> acc1.combine(acc2, downstream.combiner());
+
+        Function<Accumulator<T, A>, R> finisher = acc -> {
+            if (!acc.values.isEmpty()) {
+                downstream.accumulator().accept(acc.downstreamAccumulator, acc.values);
+            }
+            return downstream.finisher().apply(acc.downstreamAccumulator);
+        };
+
+        return Collector.of(supplier, accumulator, combiner, finisher, Collector.Characteristics.UNORDERED);
+    }
+
+    static class Accumulator<T, A> {
+        private final List<T> values = new ArrayList<>();
+        private final int batchSize;
+        private A downstreamAccumulator;
+        private final BiConsumer<A, List<T>> batchFullListener;
+
+        Accumulator(int batchSize, A accumulator, BiConsumer<A, List<T>> onBatchFull) {
+            this.batchSize = batchSize;
+            this.downstreamAccumulator = accumulator;
+            this.batchFullListener = onBatchFull;
+        }
+
+        void add(T value) {
+            values.add(value);
+            if (values.size() == batchSize) {
+                batchFullListener.accept(downstreamAccumulator, new ArrayList<>(values));
+                values.clear();
+            }
+        }
+
+        Accumulator<T, A> combine(Accumulator<T, A> other, BinaryOperator<A> accumulatorCombiner) {
+            this.downstreamAccumulator = accumulatorCombiner.apply(downstreamAccumulator, other.downstreamAccumulator);
+            other.values.forEach(this::add);
+            return this;
+        }
+    }
+
+}

core-java-modules/core-java-streams-5/src/test/java/com/baeldung/partitioning/PartitionStreamsUnitTest.java

@@ -0,0 +1,82 @@
+package com.baeldung.partitioning;
+
+import static com.baeldung.streams.partitioning.PartitionStream.partitionList;
+import static com.baeldung.streams.partitioning.PartitionStream.partitionStream;
+import static com.baeldung.streams.partitioning.PartitionStream.partitionUsingGuava;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.assertj.core.api.Assertions.atIndex;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.Test;
+
+public class PartitionStreamsUnitTest {
+
+    @Test
+    void whenPartitionList_thenReturnThreeSubLists() {
+        List<Integer> source = List.of(1, 2, 3, 4, 5, 6, 7, 8);
+
+        Stream<List<Integer>> result = partitionList(source, 3);
+
+        assertThat(result)
+          .containsExactlyInAnyOrder(
+            List.of(1, 2, 3),
+            List.of(4, 5, 6),
+            List.of(7, 8)
+          );
+    }
+
+    @Test
+    void whenPartitionEmptyList_thenReturnEmptyStream() {
+        Stream<List<Integer>> result = partitionList(Collections.emptyList(), 3);
+
+        assertThat(result).isEmpty();
+    }
+
+    @Test
+    void whenPartitionListWithNegativeBatchSize_thenThrowException() {
+        assertThatThrownBy(() -> partitionList(List.of(1,2,3), -1))
+          .isInstanceOf(IllegalArgumentException.class)
+          .hasMessage("Expected the batchSize to be greater than ZERO, actual value was: -1");
+    }
+
+    @Test
+    void whenPartitionParallelStream_thenReturnThreeSubLists() {
+        Stream<Integer> source = Stream.of(1, 2, 3, 4, 5, 6, 7, 8).parallel();
+
+        List<List<Integer>> result = partitionStream(source, 3);
+
+        assertThat(result)
+          .hasSize(3)
+          .satisfies(batch -> assertThat(batch).hasSize(3), atIndex(0))
+          .satisfies(batch -> assertThat(batch).hasSize(3), atIndex(1))
+          .satisfies(batch -> assertThat(batch).hasSize(2), atIndex(2));
+    }
+
+    @Test
+    void whenPartitionEmptyParallelStream_thenReturnEmptyList() {
+        Stream<Integer> source = Stream.<Integer>empty().parallel();
+
+        List<List<Integer>> result = partitionStream(source, 3);
+
+        assertThat(result).isEmpty();
+    }
+
+    @Test
+    void whenPartitionParallelStreamWithGuava_thenReturnThreeSubLists() {
+        Stream<Integer> source = Stream.of(1, 2, 3, 4, 5, 6, 7, 8).parallel();
+
+        Iterable<List<Integer>> result = partitionUsingGuava(source, 3);
+
+        assertThat(result)
+          .map(ArrayList::new)
+          .hasSize(3)
+          .satisfies(batch -> assertThat(batch).asList().hasSize(3), atIndex(0))
+          .satisfies(batch -> assertThat(batch).asList().hasSize(3), atIndex(1))
+          .satisfies(batch -> assertThat(batch).asList().hasSize(2), atIndex(2));
+    }
+}

core-java-modules/core-java-string-algorithms-3/README.md

@@ -12,3 +12,4 @@ This module contains articles about string-related algorithms.
 - [Find the First Embedded Occurrence of an Integer in a Java String](https://www.baeldung.com/java-string-find-embedded-integer)
 - [Find the Most Frequent Characters in a String](https://www.baeldung.com/java-string-find-most-frequent-characters)
 - [Checking If a String Is a Repeated Substring](https://www.baeldung.com/java-repeated-substring)
+- [Check if Letter Is Emoji With Java](https://www.baeldung.com/java-check-letter-emoji)

core-java-modules/core-java-string-apis/src/test/java/com/baeldung/charsequence/CharSequenceVsStringUnitTest.java

@@ -1,11 +1,11 @@
 package com.baeldung.charsequence;
 
-import org.junit.Test;
-
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertTrue;
 
+import org.junit.Test;
+
 public class CharSequenceVsStringUnitTest {
 
     @Test
@@ -44,4 +44,43 @@ public class CharSequenceVsStringUnitTest {
 
         assertEquals(firstAddressOfTest, secondAddressOfTest);
     }
+
+    @Test
+    public void givenCharSequenceAsString_whenConvertingUsingCasting_thenCorrect() {
+        String expected = "baeldung";
+        CharSequence charSequence = "baeldung";
+        String explicitCastedString = (String) charSequence;
+
+        assertEquals(expected, charSequence);
+        assertEquals(expected, explicitCastedString);
+    }
+
+    @Test(expected = ClassCastException.class)
+    public void givenCharSequenceAsStringBuiler_whenConvertingUsingCasting_thenThrowException() {
+        CharSequence charSequence = new StringBuilder("baeldung");
+        String castedString = (String) charSequence;
+    }
+
+    @Test
+    public void givenCharSequence_whenConvertingUsingToString_thenCorrect() {
+        String expected = "baeldung";
+        CharSequence charSequence1 = "baeldung";
+        CharSequence charSequence2 = new StringBuilder("baeldung");
+
+        assertEquals(expected, charSequence1.toString());
+        assertEquals(expected, charSequence2.toString());
+    }
+
+    @Test
+    public void givenCharSequence_whenConvertingUsingValueOf_thenCorrect() {
+        String expected = "baeldung";
+        CharSequence charSequence1 = "baeldung";
+        CharSequence charSequence2 = new StringBuilder("baeldung");
+        CharSequence charSequence3 = null;
+
+        assertEquals(expected, String.valueOf(charSequence1));
+        assertEquals(expected, String.valueOf(charSequence2));
+        assertEquals("null", String.valueOf(charSequence3));
+    }
+
 }

core-java-modules/core-java-string-operations-5/README.md

@@ -11,4 +11,3 @@
 - [Check if the First Letter of a String Is a Number](https://www.baeldung.com/java-check-if-string-starts-with-number)
 - [Print “” Quotes Around a String in Java](https://www.baeldung.com/java-string-print-quotes)
 - [Remove Punctuation From a String in Java](https://www.baeldung.com/java-remove-punctuation-from-string)
-- [Replacing Single Quote with \’ in Java String](https://www.baeldung.com/java-replacing-single-quote-string)

core-java-modules/core-java-string-operations-6/README.md

@@ -10,3 +10,5 @@
 - [Check if a String Contains Non-Alphanumeric Characters](https://www.baeldung.com/java-string-test-special-characters)
 - [Check if a String Has All Unique Characters in Java](https://www.baeldung.com/java-check-string-all-unique-chars)
 - [Performance Comparison Between Different Java String Concatenation Methods](https://www.baeldung.com/java-string-concatenation-methods)
+- [Replacing Single Quote with \’ in Java String](https://www.baeldung.com/java-replacing-single-quote-string)
+

core-java-modules/pom.xml

@@ -28,13 +28,14 @@
         <!--<module>core-java-streams-2</module> -->
         <!--<module>core-java-sun</module> -->
         <module>core-java-9-improvements</module>
-        <module>core-java-collections-array-list</module>
         <module>core-java-9-streams</module>
         <module>core-java-9</module>
         <module>core-java-10</module>
         <module>core-java-11</module>
         <module>core-java-11-2</module>
         <module>core-java-11-3</module>
+        <module>core-java-collections-array-list</module>
+        <module>core-java-collections-array-list-2</module>
         <module>core-java-collections-list-4</module>
         <module>core-java-collections-list-5</module>
         <module>core-java-collections-maps-4</module>
@@ -82,6 +83,7 @@
         <module>core-java-collections-maps</module>
         <module>core-java-collections-maps-2</module>
         <module>core-java-collections-maps-3</module>
+        <module>core-java-collections-maps-7</module>
         <module>core-java-compiler</module>
         <module>core-java-concurrency-2</module>
         <module>core-java-concurrency-advanced</module>
@@ -109,6 +111,7 @@
         <module>core-java-io-2</module>
         <module>core-java-io-3</module>
         <module>core-java-io-4</module>
+        <module>core-java-io-5</module>
         <module>core-java-io-apis</module>
         <module>core-java-io-apis-2</module>
         <module>core-java-io-conversions</module>

jenkins-modules/plugins/pom.xml

@@ -12,6 +12,7 @@
         <groupId>org.jenkins-ci.plugins</groupId>
         <artifactId>plugin</artifactId>
         <version>2.33</version>
+        <relativePath/>
     </parent>
 
     <dependencies>

jersey/pom.xml

@@ -76,6 +76,11 @@
             <artifactId>jersey-apache-connector</artifactId>
             <version>${jersey.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.glassfish.jersey.media</groupId>
+            <artifactId>jersey-media-multipart</artifactId>
+            <version>${jersey.version}</version>
+        </dependency>
     </dependencies>
 
     <build>

jersey/src/main/java/com/baeldung/jersey/server/form/FormExampleResource.java

@@ -0,0 +1,61 @@
+package com.baeldung.jersey.server.form;
+
+import jakarta.ws.rs.*;
+import jakarta.ws.rs.core.MediaType;
+import org.glassfish.jersey.media.multipart.FormDataParam;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.InputStream;
+
+@Path("form")
+public class FormExampleResource
+{
+    @GET
+    @Path("/example1")
+    @Produces({MediaType.TEXT_HTML})
+    public InputStream getExample1() throws Exception
+    {
+        File f = new File("src/main/resources/html/example1.html");
+        return new FileInputStream(f);
+    }
+
+    @GET
+    @Path("/example2")
+    @Produces({MediaType.TEXT_HTML})
+    public InputStream getExample2() throws Exception
+    {
+        File f = new File("src/main/resources/html/example2.html");
+        return new FileInputStream(f);
+    }
+
+    @POST
+    @Path("/example1")
+    public String example1(@FormParam("first_name") String firstName,
+                           @FormParam("last_name") String lastName,
+                           @FormParam("age") String age)
+    {
+        return "Got: First = " + firstName + ", Last = " + lastName + ", Age = " + age;
+    }
+
+    @POST
+    @Path("/example2")
+    @Consumes(MediaType.MULTIPART_FORM_DATA)
+    public String example2(@FormDataParam("first_name") String firstName,
+                           @FormDataParam("last_name") String lastName,
+                           @FormDataParam("age") String age,
+                           @FormDataParam("photo") InputStream photo)
+            throws Exception
+    {
+        int len;
+        int size = 1024;
+        byte[] buf;
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        buf = new byte[size];
+        while ((len = photo.read(buf, 0, size)) != -1)
+            bos.write(buf, 0, len);
+        buf = bos.toByteArray();
+        return "Got: First = " + firstName + ", Last = " + lastName + ", Age = " + age + ", Photo (# of bytes) = " + buf.length;
+    }
+}

jersey/src/main/resources/formexamples/example1.html

@@ -0,0 +1,16 @@
+<html>
+<head>
+    <title>Example 1 using @FormParam</title>
+</head>
+<body>
+<form method="post" action="/form/example1">
+    <label for="first_name">First Name</label>
+    <input id="first_name" name="first_name" type="text">
+    <label for="last_name">Last Name</label>
+    <input id="last_name" name="last_name" type="text">
+    <label for="age">Age</label>
+    <input id="age" name="age" type="text">
+    <input type="submit">
+</form>
+</body>
+</html>

jersey/src/main/resources/formexamples/example2.html

@@ -0,0 +1,18 @@
+<html>
+<head>
+    <title>Example 2 using @FormDataParam</title>
+</head>
+<body>
+<form method="post" action="/form/example2" enctype="multipart/form-data">
+    <label for="first_name">First Name</label>
+    <input id="first_name" name="first_name" type="text">
+    <label for="last_name">Last Name</label>
+    <input id="last_name" name="last_name" type="text">
+    <label for="age">Age</label>
+    <input id="age" name="age" type="text">
+    <label for="photo">Profile Photo</label>
+    <input id="photo" name="photo" type="file">
+    <input type="submit">
+</form>
+</body>
+</html>

libraries-apache-commons-2/pom.xml

@@ -28,12 +28,18 @@
             <artifactId>commons-vfs2</artifactId>
             <version>${commons-vfs2.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-text</artifactId>
+            <version>${apache-commons-text.version}</version>
+        </dependency>
     </dependencies>
 
     <properties>
         <commons-compress.version>1.23.0</commons-compress.version>
         <ant.version>1.10.13</ant.version>
         <commons-vfs2.version>2.9.0</commons-vfs2.version>
+        <apache-commons-text.version>1.10.0</apache-commons-text.version>
     </properties>
 
 </project>

libraries-apache-commons-2/src/main/java/com/baeldung/commons/convertunicode/UnicodeConverterUtil.java

@@ -0,0 +1,29 @@
+package com.baeldung.commons.convertunicode;
+
+import org.apache.commons.text.StringEscapeUtils;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class UnicodeConverterUtil {
+
+    public static String decodeWithApacheCommons(String input) {
+        return StringEscapeUtils.unescapeJava(input);
+    }
+
+    public static String decodeWithPlainJava(String input) {
+        Pattern pattern = Pattern.compile("\\\\u[0-9a-fA-F]{4}");
+        Matcher matcher = pattern.matcher(input);
+
+        StringBuilder decodedString = new StringBuilder();
+
+        while (matcher.find()) {
+            String unicodeSequence = matcher.group();
+            char unicodeChar = (char) Integer.parseInt(unicodeSequence.substring(2), 16);
+            matcher.appendReplacement(decodedString, Character.toString(unicodeChar));
+        }
+
+        matcher.appendTail(decodedString);
+        return decodedString.toString();
+    }
+}

libraries-apache-commons-2/src/test/java/com/baeldung/commons/convertunicode/UnicodeConverterUnitTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.commons.convertunicode;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class UnicodeConverterUnitTest {
+
+    @Test
+    public void whenInputHaveUnicodeSequences_ThenDecode() {
+        String encodedString = "\\u0048\\u0065\\u006C\\u006C\\u006F World";
+        String expectedDecodedString = "Hello World";
+        assertEquals(expectedDecodedString, UnicodeConverterUtil.decodeWithApacheCommons(encodedString));
+        assertEquals(expectedDecodedString, UnicodeConverterUtil.decodeWithPlainJava(encodedString));
+    }
+
+    @Test
+    public void whenInputHaveNoUnicodeSequences_ThenDoNothing() {
+        String inputString = "Hello World";
+        assertEquals(inputString, UnicodeConverterUtil.decodeWithApacheCommons(inputString));
+        assertEquals(inputString, UnicodeConverterUtil.decodeWithPlainJava(inputString));
+    }
+
+    @Test
+    public void whenInputHaveUnicodeSequencesInMiddle_ThenDecode() {
+        String encodedString = "This is a test \\u0069\\u006E the middle.";
+        String expectedDecodedString = "This is a test in the middle.";
+        assertEquals(expectedDecodedString, UnicodeConverterUtil.decodeWithApacheCommons(encodedString));
+        assertEquals(expectedDecodedString, UnicodeConverterUtil.decodeWithPlainJava(encodedString));
+    }
+
+    @Test
+    public void whenInputHaveMultipleUnicodeSequences_ThenDecode() {
+        String encodedString = "Unicode: \\u0048\\u0065\\u006C\\u006C\\u006F \\u0057\\u006F\\u0072\\u006C\\u0064";
+        String expectedDecodedString = "Unicode: Hello World";
+        assertEquals(expectedDecodedString, UnicodeConverterUtil.decodeWithApacheCommons(encodedString));
+        assertEquals(expectedDecodedString, UnicodeConverterUtil.decodeWithPlainJava(encodedString));
+    }
+}

libraries-io/pom.xml

@@ -5,6 +5,18 @@
     <modelVersion>4.0.0</modelVersion>
     <artifactId>libraries-io</artifactId>
     <name>libraries-io</name>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>17</source>
+                    <target>17</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 
     <parent>
         <groupId>com.baeldung</groupId>
@@ -34,6 +46,11 @@
             <artifactId>zip4j</artifactId>
             <version>${zip4j.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.opencsv</groupId>
+            <artifactId>opencsv</artifactId>
+            <version>${opencsv.version}</version>
+        </dependency>
     </dependencies>
 
     <properties>
@@ -42,6 +59,10 @@
         <sshj.version>0.27.0</sshj.version>
         <vfs.version>2.4</vfs.version>
         <zip4j.version>2.9.0</zip4j.version>
+        <opencsv.version>5.7.1</opencsv.version>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
 
 </project>

libraries-io/src/main/java/com/baeldung/java/io/pojotocsv/Application.java

@@ -0,0 +1,4 @@
+package com.baeldung.java.io.pojotocsv;
+
+public record Application(String id, String name, Integer age, String created_at) {
+}

libraries-io/src/main/java/com/baeldung/java/io/pojotocsv/ApplicationWithAnnotation.java

@@ -0,0 +1,8 @@
+package com.baeldung.java.io.pojotocsv;
+
+import com.opencsv.bean.CsvBindByName;
+import com.opencsv.bean.CsvBindByPosition;
+
+public record ApplicationWithAnnotation(@CsvBindByName(column = "id", required = true) @CsvBindByPosition(position = 1) String id, @CsvBindByName(column = "name", required = true) @CsvBindByPosition(position = 0) String name,
+                                        @CsvBindByName(column = "age", required = true) @CsvBindByPosition(position = 2) Integer age, @CsvBindByName(column = "position", required = true) @CsvBindByPosition(position = 3) String created_at) {
+}

libraries-io/src/main/java/com/baeldung/java/io/pojotocsv/BeanToCsv.java

@@ -0,0 +1,55 @@
+package com.baeldung.java.io.pojotocsv;
+
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.List;
+
+import com.opencsv.CSVWriter;
+import com.opencsv.bean.StatefulBeanToCsvBuilder;
+import com.opencsv.exceptions.CsvDataTypeMismatchException;
+import com.opencsv.exceptions.CsvRequiredFieldEmptyException;
+
+public class BeanToCsv {
+
+    public void beanToCSVWithDefault(List<Application> applications) throws Exception {
+        try (FileWriter writer = new FileWriter("src/main/resources/application.csv")) {
+            var builder = new StatefulBeanToCsvBuilder<Application>(writer).withQuotechar(CSVWriter.NO_QUOTE_CHARACTER)
+                .withSeparator(',')
+                .build();
+            builder.write(applications);
+        }
+    }
+
+    public void beanToCSVWithCustomHeaderStrategy(List<Application> applications) throws IOException, CsvRequiredFieldEmptyException, CsvDataTypeMismatchException {
+        try (FileWriter writer = new FileWriter("src/main/resources/application2.csv")) {
+            var mappingStrategy = new CustomHeaderStrategy<Application>();
+            mappingStrategy.setType(Application.class);
+
+            var builder = new StatefulBeanToCsvBuilder<Application>(writer).withQuotechar(CSVWriter.NO_QUOTE_CHARACTER)
+                .withMappingStrategy(mappingStrategy)
+                .build();
+            builder.write(applications);
+        }
+    }
+
+    public void beanToCSVWithCustomPositionStrategy(List<ApplicationWithAnnotation> applications) throws Exception {
+        try (FileWriter writer = new FileWriter("src/main/resources/application3.csv")) {
+            var builder = new StatefulBeanToCsvBuilder<ApplicationWithAnnotation>(writer).withQuotechar(CSVWriter.NO_QUOTE_CHARACTER)
+                .build();
+            builder.write(applications);
+        }
+    }
+
+    public void beanToCSVWithCustomHeaderAndPositionStrategy(List<ApplicationWithAnnotation> applications) throws IOException, CsvRequiredFieldEmptyException, CsvDataTypeMismatchException {
+        try (FileWriter writer = new FileWriter("src/main/resources/application4.csv")) {
+            var mappingStrategy = new CustomColumnPositionStrategy<ApplicationWithAnnotation>();
+            mappingStrategy.setType(ApplicationWithAnnotation.class);
+
+            var builder = new StatefulBeanToCsvBuilder<ApplicationWithAnnotation>(writer).withQuotechar(CSVWriter.NO_QUOTE_CHARACTER)
+                .withMappingStrategy(mappingStrategy)
+                .build();
+            builder.write(applications);
+        }
+    }
+
+}

libraries-io/src/main/java/com/baeldung/java/io/pojotocsv/CustomColumnPositionStrategy.java

@@ -0,0 +1,12 @@
+package com.baeldung.java.io.pojotocsv;
+
+import com.opencsv.bean.ColumnPositionMappingStrategy;
+import com.opencsv.exceptions.CsvRequiredFieldEmptyException;
+
+public class CustomColumnPositionStrategy<T> extends ColumnPositionMappingStrategy<T> {
+    @Override
+    public String[] generateHeader(T bean) throws CsvRequiredFieldEmptyException {
+        super.generateHeader(bean);
+        return super.getColumnMapping();
+    }
+}

libraries-io/src/main/java/com/baeldung/java/io/pojotocsv/CustomHeaderStrategy.java

@@ -0,0 +1,16 @@
+package com.baeldung.java.io.pojotocsv;
+
+import java.util.Arrays;
+
+import com.opencsv.bean.HeaderColumnNameMappingStrategy;
+import com.opencsv.exceptions.CsvRequiredFieldEmptyException;
+
+public class CustomHeaderStrategy<T> extends HeaderColumnNameMappingStrategy<T> {
+    @Override
+    public String[] generateHeader(T bean) throws CsvRequiredFieldEmptyException {
+        String[] header = super.generateHeader(bean);
+        return Arrays.stream(header)
+            .map(String::toLowerCase)
+            .toArray(String[]::new);
+    }
+}

libraries-io/src/main/resources/application.csv

@@ -0,0 +1,4 @@
+AGE,CREATED_AT,ID,NAME
+34,2023-08-11,123,Sam
+44,2023-02-11,456,Tam
+54,2023-03-11,890,Jam

libraries-io/src/main/resources/application2.csv

@@ -0,0 +1,4 @@
+age,created_at,id,name
+34,2023-08-11,123,Sam
+44,2023-02-11,456,Tam
+54,2023-03-11,890,Jam