Merge remote-tracking branch 'origin/master'

2023-05-12 20:19:50 +03:00
parent b8f751d3d7 42897274b9
commit 5c420784f5
2825 changed files with 38918 additions and 8860 deletions
@@ -4,7 +4,6 @@
    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-10</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-10</name>
    <packaging>jar</packaging>

@@ -4,7 +4,6 @@
    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-11-2</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-11-2</name>
    <packaging>jar</packaging>

@@ -4,7 +4,6 @@
    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-11-3</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-11-3</name>
    <packaging>jar</packaging>

@@ -14,7 +13,7 @@
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../../pom.xml</relativePath>
    </parent>
-    
+
    <dependencies>
        <dependency>
            <groupId>com.google.code.gson</groupId>
@@ -4,10 +4,8 @@
    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-11</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-11</name>
    <packaging>jar</packaging>
-    <url>http://maven.apache.org</url>

    <parent>
        <groupId>com.baeldung</groupId>
@@ -4,10 +4,8 @@
    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-12</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-12</name>
    <packaging>jar</packaging>
-    <url>http://maven.apache.org</url>

    <parent>
        <groupId>com.baeldung</groupId>
@@ -3,12 +3,9 @@
    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>
-    <groupId>com.baeldung</groupId>
    <artifactId>core-java-13</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-13</name>
    <packaging>jar</packaging>
-    <url>http://maven.apache.org</url>

    <parent>
        <groupId>com.baeldung</groupId>
@@ -13,3 +13,4 @@ This module contains articles about Java 14.
 - [New Features in Java 14](https://www.baeldung.com/java-14-new-features)
 - [Java 14 Record vs. Lombok](https://www.baeldung.com/java-record-vs-lombok)
 - [Record vs. Final Class in Java](https://www.baeldung.com/java-record-vs-final-class)
+- [Custom Constructor in Java Records](https://www.baeldung.com/java-records-custom-constructor)
@@ -6,7 +6,6 @@
    <artifactId>core-java-14</artifactId>
    <name>core-java-14</name>
    <packaging>jar</packaging>
-    <url>http://maven.apache.org</url>

    <parent>
        <groupId>com.baeldung</groupId>
@@ -0,0 +1,61 @@
+package org.example;
+
+import java.util.Objects;
+
+public class StudentClassic {
+    private String name;
+    private int rollNo;
+    private int marks;
+
+    public StudentClassic(String name, int rollNo, int marks) {
+        this.name = name;
+        this.rollNo = rollNo;
+        this.marks = marks;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getRollNo() {
+        return rollNo;
+    }
+
+    public int getMarks() {
+        return marks;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public void setRollNo(int rollNo) {
+        this.rollNo = rollNo;
+    }
+
+    public void setMarks(int marks) {
+        this.marks = marks;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        StudentClassic that = (StudentClassic) o;
+        return rollNo == that.rollNo && marks == that.marks && Objects.equals(name, that.name);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, rollNo, marks);
+    }
+
+    @Override
+    public String toString() {
+        return "StudentClassic{" +
+                "name='" + name + '\'' +
+                ", rollNo=" + rollNo +
+                ", marks=" + marks +
+                '}';
+    }
+}
@@ -0,0 +1,19 @@
+package org.example;
+
+import java.util.Comparator;
+import java.util.List;
+
+public record StudentRecord(String name, int rollNo, int marks) {
+    public StudentRecord(String name){
+        this(name, 0,0);
+    }
+    public StudentRecord {
+        if (marks < 0 || marks > 100) {
+            throw new IllegalArgumentException("Marks should be between 0 and 100.");
+        }
+        if (name == null) {
+            throw new IllegalArgumentException("Name cannot be null");
+        }
+    }
+}
+
@@ -0,0 +1,22 @@
+package org.example;
+
+record StudentRecordV2(String name, int rollNo, int marks, char grade) {
+    public StudentRecordV2(String name, int rollNo, int marks) {
+        this(name, rollNo, marks, calculateGrade(marks));
+    }
+
+    private static char calculateGrade(int marks) {
+        if (marks >= 90) {
+            return 'A';
+        } else if (marks >= 80) {
+            return 'B';
+        } else if (marks >= 70) {
+            return 'C';
+        } else if (marks >= 60) {
+            return 'D';
+        } else {
+            return 'F';
+        }
+    }
+}
+
@@ -0,0 +1,11 @@
+package org.example;
+
+import java.util.UUID;
+
+record StudentRecordV3(String name, int rollNo, int marks, String id) {
+
+    public StudentRecordV3(String name, int rollNo, int marks) {
+        this(name, rollNo, marks, UUID.randomUUID().toString());
+    }
+}
+
@@ -0,0 +1,37 @@
+import org.example.StudentRecord;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+
+public class StudentRecordJUnitTest {
+
+    @Test
+    public void givenStudentRecordData_whenCreated_thenStudentPropertiesMatch() {
+        StudentRecord s1 = new StudentRecord("John", 1, 90);
+        StudentRecord s2 = new StudentRecord("Jane", 2, 80);
+        assertEquals("John", s1.name());
+        assertEquals(1, s1.rollNo());
+        assertEquals(90, s1.marks());
+        assertEquals("Jane", s2.name());
+        assertEquals(2, s2.rollNo());
+        assertEquals(80, s2.marks());
+    }
+    @Test
+    public void givenStudentRecordsList_whenSortingDataWithName_thenStudentsSorted(){
+        List<StudentRecord> studentRecords = List.of(
+                new StudentRecord("Dana", 1, 85),
+                new StudentRecord("Jim", 2, 90),
+                new StudentRecord("Jane", 3, 80)
+        );
+
+        List<StudentRecord> mutableStudentRecords = new ArrayList<>(studentRecords);
+        mutableStudentRecords.sort(Comparator.comparing(StudentRecord::name));
+
+        List<StudentRecord> sortedStudentRecords = List.copyOf(mutableStudentRecords);
+        assertEquals("Jane", sortedStudentRecords.get(1).name());
+    }
+}
@@ -6,7 +6,6 @@
    <artifactId>core-java-15</artifactId>
    <name>core-java-15</name>
    <packaging>jar</packaging>
-    <url>http://maven.apache.org</url>

    <parent>
        <groupId>com.baeldung</groupId>
@@ -4,10 +4,8 @@
    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-16</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-16</name>
    <packaging>jar</packaging>
-    <url>http://maven.apache.org</url>

    <parent>
        <groupId>com.baeldung</groupId>
@@ -6,3 +6,4 @@
 - [New Features in Java 17](https://www.baeldung.com/java-17-new-features)
 - [Random Number Generators in Java 17](https://www.baeldung.com/java-17-random-number-generators)
 - [Sealed Classes and Interfaces in Java](https://www.baeldung.com/java-sealed-classes-interfaces)
+- [Migrate From Java 8 to Java 17](https://www.baeldung.com/java-migrate-8-to-17)
@@ -4,10 +4,8 @@
    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-17</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-17</name>
    <packaging>jar</packaging>
-    <url>http://maven.apache.org</url>

    <parent>
        <groupId>com.baeldung</groupId>
@@ -1,3 +1,4 @@
 ## Relevant Articles
 - [Record Patterns in Java 19](https://www.baeldung.com/java-19-record-patterns)
 - [Structured Concurrency in Java 19](https://www.baeldung.com/java-structured-concurrency)
+- [Possible Root Causes for High CPU Usage in Java](https://www.baeldung.com/java-high-cpu-usage-causes)
@@ -1,21 +1,17 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
+    <artifactId>core-java-19</artifactId>
+    <name>core-java-19</name>
+
    <parent>
        <groupId>com.baeldung.core-java-modules</groupId>
        <artifactId>core-java-modules</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

-    <artifactId>core-java-19</artifactId>
-
-    <properties>
-        <maven.compiler.source>19</maven.compiler.source>
-        <maven.compiler.target>19</maven.compiler.target>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    </properties>
    <build>
        <plugins>
            <plugin>
@@ -30,4 +26,10 @@
        </plugins>
    </build>

+    <properties>
+        <maven.compiler.source>19</maven.compiler.source>
+        <maven.compiler.target>19</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
 </project>
@@ -0,0 +1,20 @@
+package com.baeldung.highcpu;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.function.IntUnaryOperator;
+import java.util.stream.IntStream;
+
+public class Application {
+
+    static List<Integer> generateList() {
+        return IntStream.range(0, 10000000).parallel().map(IntUnaryOperator.identity()).collect(LinkedList::new, List::add, List::addAll);
+    }
+
+    public static void main(String[] args) {
+        List<Integer> list = generateList();
+        long start = System.nanoTime();
+        int value = list.get(9500000);
+        System.out.printf("Found value %d in %d nanos\n", value, (System.nanoTime() - start));
+    }
+}
@@ -0,0 +1,2 @@
+## Relevant Articles
+- [Scoped Values in Java 20](https://www.baeldung.com/java-20-scoped-values)
@@ -0,0 +1,65 @@
+<?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>
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>core-java-20</artifactId>
+
+    <properties>
+        <maven.compiler.source>20</maven.compiler.source>
+        <maven.compiler.target>20</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>20</source>
+                    <target>20</target>
+                    <compilerArgs>
+                        <arg>--enable-preview</arg>
+                        <arg>--add-modules=jdk.incubator.concurrent</arg>
+                    </compilerArgs>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <argLine>--enable-preview --add-modules=jdk.incubator.concurrent</argLine>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>jakarta.servlet</groupId>
+            <artifactId>jakarta.servlet-api</artifactId>
+            <version>6.0.0</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>3.24.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <version>5.2.0</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+</project>
@@ -0,0 +1,33 @@
+package com.baeldung.scopedvalues.classic;
+
+import com.baeldung.scopedvalues.data.Data;
+import com.baeldung.scopedvalues.data.User;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.Optional;
+
+public class Controller {
+
+    private final Service service = new Service();
+
+    public void processRequest(HttpServletRequest request, HttpServletResponse response, User loggedInUser) {
+        Optional<Data> data = service.getData(request, loggedInUser);
+        if (data.isPresent()) {
+            try {
+                PrintWriter out = response.getWriter();
+                response.setContentType("application/json");
+                out.print(data.get());
+                out.flush();
+                response.setStatus(200);
+            } catch (IOException e) {
+                response.setStatus(500);
+            }
+        } else {
+            response.setStatus(400);
+        }
+    }
+
+}
@@ -0,0 +1,16 @@
+package com.baeldung.scopedvalues.classic;
+
+import com.baeldung.scopedvalues.data.Data;
+import com.baeldung.scopedvalues.data.User;
+
+import java.util.Optional;
+
+public class Repository {
+
+    public Optional<Data> getData(String id, User user) {
+        return user.isAdmin()
+                ? Optional.of(new Data(id, "Title 1", "Description 1"))
+                : Optional.empty();
+    }
+
+}
@@ -0,0 +1,42 @@
+package com.baeldung.scopedvalues.classic;
+
+import com.baeldung.scopedvalues.data.User;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.*;
+
+public class Server {
+
+    private static final List<User> AUTHENTICATED_USERS = List.of(
+            new User("1", "admin", "123456", true),
+            new User("2", "user", "123456", false)
+    );
+    private final Controller controller = new Controller();
+    private final ExecutorService executor = Executors.newFixedThreadPool(5);
+
+    public void serve(HttpServletRequest request, HttpServletResponse response) throws InterruptedException, ExecutionException {
+        Optional<User> user = authenticateUser(request);
+        if (user.isPresent()) {
+            Future<?> future = executor.submit(() ->
+                    controller.processRequest(request, response, user.get()));
+            future.get();
+        } else {
+            response.setStatus(401);
+        }
+    }
+
+    private Optional<User> authenticateUser(HttpServletRequest request) {
+        return AUTHENTICATED_USERS.stream()
+                .filter(user -> checkUserPassword(user, request))
+                .findFirst();
+    }
+
+    private boolean checkUserPassword(User user, HttpServletRequest request) {
+        return user.name().equals(request.getParameter("user_name"))
+                && user.password().equals(request.getParameter("user_pw"));
+    }
+
+}
@@ -0,0 +1,18 @@
+package com.baeldung.scopedvalues.classic;
+
+import com.baeldung.scopedvalues.data.Data;
+import com.baeldung.scopedvalues.data.User;
+import jakarta.servlet.http.HttpServletRequest;
+
+import java.util.Optional;
+
+public class Service {
+
+    private final Repository repository = new Repository();
+
+    public Optional<Data> getData(HttpServletRequest request, User loggedInUser) {
+        String id = request.getParameter("data_id");
+        return repository.getData(id, loggedInUser);
+    }
+
+}
@@ -0,0 +1,3 @@
+package com.baeldung.scopedvalues.data;
+
+public record Data(String id, String title, String description) {}
@@ -0,0 +1,3 @@
+package com.baeldung.scopedvalues.data;
+
+public record User(String id, String name, String password, boolean isAdmin) {}
@@ -0,0 +1,37 @@
+package com.baeldung.scopedvalues.scoped;
+
+import com.baeldung.scopedvalues.data.Data;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import jdk.incubator.concurrent.ScopedValue;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.Optional;
+
+public class Controller {
+
+    private final Service internalService = new Service();
+
+    public void processRequest(HttpServletRequest request, HttpServletResponse response) {
+        Optional<Data> data = internalService.getData(request);
+
+        ScopedValue.where(Server.LOGGED_IN_USER, null)
+                .run(internalService::extractData);
+
+        if (data.isPresent()) {
+            try {
+                PrintWriter out = response.getWriter();
+                response.setContentType("application/json");
+                out.print(data.get());
+                out.flush();
+                response.setStatus(200);
+            } catch (IOException e) {
+                response.setStatus(500);
+            }
+        } else {
+            response.setStatus(400);
+        }
+    }
+
+}
@@ -0,0 +1,17 @@
+package com.baeldung.scopedvalues.scoped;
+
+import com.baeldung.scopedvalues.data.Data;
+import com.baeldung.scopedvalues.data.User;
+
+import java.util.Optional;
+
+public class Repository {
+
+    public Optional<Data> getData(String id) {
+        User loggedInUser = Server.LOGGED_IN_USER.get();
+        return loggedInUser.isAdmin()
+                ? Optional.of(new Data(id, "Title 1", "Description 1"))
+                : Optional.empty();
+    }
+
+}
@@ -0,0 +1,41 @@
+package com.baeldung.scopedvalues.scoped;
+
+import com.baeldung.scopedvalues.data.User;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import jdk.incubator.concurrent.ScopedValue;
+
+import java.util.List;
+import java.util.Optional;
+
+public class Server {
+
+    private static final List<User> AUTHENTICATED_USERS = List.of(
+            new User("1", "admin", "123456", true),
+            new User("2", "user", "123456", false)
+    );
+    public final static ScopedValue<User> LOGGED_IN_USER = ScopedValue.newInstance();
+    private final Controller controller = new Controller();
+
+    public void serve(HttpServletRequest request, HttpServletResponse response) {
+        Optional<User> user = authenticateUser(request);
+        if (user.isPresent()) {
+            ScopedValue.where(LOGGED_IN_USER, user.get())
+                    .run(() -> controller.processRequest(request, response));
+        } else {
+            response.setStatus(401);
+        }
+    }
+
+    private Optional<User> authenticateUser(HttpServletRequest request) {
+        return AUTHENTICATED_USERS.stream()
+                .filter(user -> checkUserPassword(user, request))
+                .findFirst();
+    }
+
+    private boolean checkUserPassword(User user, HttpServletRequest request) {
+        return user.name().equals(request.getParameter("user_name"))
+                && user.password().equals(request.getParameter("user_pw"));
+    }
+
+}
@@ -0,0 +1,23 @@
+package com.baeldung.scopedvalues.scoped;
+
+import com.baeldung.scopedvalues.data.Data;
+import com.baeldung.scopedvalues.data.User;
+import jakarta.servlet.http.HttpServletRequest;
+
+import java.util.Optional;
+
+public class Service {
+
+    private final Repository repository = new Repository();
+
+    public Optional<Data> getData(HttpServletRequest request) {
+        String id = request.getParameter("data_id");
+        return repository.getData(id);
+    }
+
+    public void extractData() {
+        User loggedInUser = Server.LOGGED_IN_USER.get();
+        assert loggedInUser == null;
+    }
+
+}
@@ -0,0 +1,44 @@
+package com.baeldung.scopedvalues.scoped.inheriting;
+
+import com.baeldung.scopedvalues.data.Data;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import jdk.incubator.concurrent.StructuredTaskScope;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.Optional;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+
+public class Controller {
+
+    private final InternalService internalService = new InternalService();
+    private final ExternalService externalService = new ExternalService();
+
+    public void processRequest(HttpServletRequest request, HttpServletResponse response) {
+        try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {
+            Future<Optional<Data>> internalData = scope.fork(() -> internalService.getData(request));
+            Future<String> externalData = scope.fork(externalService::getData);
+            try {
+                scope.join();
+                scope.throwIfFailed();
+
+                Optional<Data> data = internalData.resultNow();
+                if (data.isPresent()) {
+                    PrintWriter out = response.getWriter();
+                    response.setContentType("application/json");
+                    out.println(data.get());
+                    out.print(externalData.resultNow());
+                    out.flush();
+                    response.setStatus(200);
+                } else {
+                    response.setStatus(400);
+                }
+            } catch (InterruptedException | ExecutionException | IOException e) {
+                response.setStatus(500);
+            }
+        }
+    }
+
+}
@@ -0,0 +1,9 @@
+package com.baeldung.scopedvalues.scoped.inheriting;
+
+public class ExternalService {
+
+    public String getData() {
+        return "External data";
+    }
+
+}
@@ -0,0 +1,17 @@
+package com.baeldung.scopedvalues.scoped.inheriting;
+
+import com.baeldung.scopedvalues.data.Data;
+import jakarta.servlet.http.HttpServletRequest;
+
+import java.util.Optional;
+
+public class InternalService {
+
+    private final Repository repository = new Repository();
+
+    public Optional<Data> getData(HttpServletRequest request) {
+        String id = request.getParameter("data_id");
+        return repository.getData(id);
+    }
+
+}
@@ -0,0 +1,17 @@
+package com.baeldung.scopedvalues.scoped.inheriting;
+
+import com.baeldung.scopedvalues.data.Data;
+import com.baeldung.scopedvalues.data.User;
+
+import java.util.Optional;
+
+public class Repository {
+
+    public Optional<Data> getData(String id) {
+        User loggedInUser = Server.LOGGED_IN_USER.get();
+        return loggedInUser.isAdmin()
+                ? Optional.of(new Data(id, "Title 1", "Description 1"))
+                : Optional.empty();
+    }
+
+}
@@ -0,0 +1,41 @@
+package com.baeldung.scopedvalues.scoped.inheriting;
+
+import com.baeldung.scopedvalues.data.User;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import jdk.incubator.concurrent.ScopedValue;
+
+import java.util.List;
+import java.util.Optional;
+
+public class Server {
+
+    private static final List<User> AUTHENTICATED_USERS = List.of(
+            new User("1", "admin", "123456", true),
+            new User("2", "user", "123456", false)
+    );
+    public final static ScopedValue<User> LOGGED_IN_USER = ScopedValue.newInstance();
+    private final Controller controller = new Controller();
+
+    public void serve(HttpServletRequest request, HttpServletResponse response) {
+        Optional<User> user = authenticateUser(request);
+        if (user.isPresent()) {
+            ScopedValue.where(LOGGED_IN_USER, user.get())
+                    .run(() -> controller.processRequest(request, response));
+        } else {
+            response.setStatus(401);
+        }
+    }
+
+    private Optional<User> authenticateUser(HttpServletRequest request) {
+        return AUTHENTICATED_USERS.stream()
+                .filter(user -> checkUserPassword(user, request))
+                .findFirst();
+    }
+
+    private boolean checkUserPassword(User user, HttpServletRequest request) {
+        return user.name().equals(request.getParameter("user_name"))
+                && user.password().equals(request.getParameter("user_pw"));
+    }
+
+}
@@ -0,0 +1,52 @@
+package com.baeldung.scopedvalues.classic;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.concurrent.ExecutionException;
+
+import static org.mockito.Mockito.*;
+import static org.assertj.core.api.Assertions.*;
+@ExtendWith(MockitoExtension.class)
+public class ServerUnitTest {
+
+    @Mock
+    private HttpServletRequest request;
+
+    @Mock
+    private HttpServletResponse response;
+
+    private final StringWriter writer = new StringWriter();
+
+    private final Server server = new Server();
+
+    @Test
+    void givenMockedRequestWithAdminCredentials_whenServeMethodIsCalled_thenDataIsReturned() throws InterruptedException, IOException, ExecutionException {
+        when(request.getParameter("user_name")).thenReturn("admin");
+        when(request.getParameter("user_pw")).thenReturn("123456");
+        when(request.getParameter("data_id")).thenReturn("1");
+        when(response.getWriter()).thenReturn(new PrintWriter(writer));
+
+        server.serve(request, response);
+
+        assertThat(writer.toString()).isEqualTo("Data[id=1, title=Title 1, description=Description 1]");
+    }
+
+    @Test
+    void givenMockedRequestWithUserCredentials_whenServeMethodIsCalled_thenNoDataIsReturned() throws InterruptedException, ExecutionException {
+        when(request.getParameter("user_name")).thenReturn("user");
+        when(request.getParameter("user_pw")).thenReturn("123456");
+
+        server.serve(request, response);
+
+        assertThat(writer.toString()).isEqualTo("");
+    }
+
+}
@@ -0,0 +1,52 @@
+package com.baeldung.scopedvalues.scoped;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+public class ServerUnitTest {
+
+    @Mock
+    private HttpServletRequest request;
+
+    @Mock
+    private HttpServletResponse response;
+
+    private final StringWriter writer = new StringWriter();
+
+    private final Server server = new Server();
+
+    @Test
+    void givenMockedRequestWithAdminCredentials_whenServeMethodIsCalled_thenDataIsReturned() throws IOException {
+        when(request.getParameter("user_name")).thenReturn("admin");
+        when(request.getParameter("user_pw")).thenReturn("123456");
+        when(request.getParameter("data_id")).thenReturn("1");
+        when(response.getWriter()).thenReturn(new PrintWriter(writer));
+
+        server.serve(request, response);
+
+        assertThat(writer.toString()).isEqualTo("Data[id=1, title=Title 1, description=Description 1]");
+    }
+
+    @Test
+    void givenMockedRequestWithUserCredentials_whenServeMethodIsCalled_thenNoDataIsReturned() throws IOException {
+        when(request.getParameter("user_name")).thenReturn("user");
+        when(request.getParameter("user_pw")).thenReturn("123456");
+
+        server.serve(request, response);
+
+        assertThat(writer.toString()).isEqualTo("");
+    }
+
+}
@@ -0,0 +1,52 @@
+package com.baeldung.scopedvalues.scoped.inheriting;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+public class ServerUnitTest {
+
+    @Mock
+    private HttpServletRequest request;
+
+    @Mock
+    private HttpServletResponse response;
+
+    private final StringWriter writer = new StringWriter();
+
+    private final Server server = new Server();
+
+    @Test
+    void givenMockedRequestWithAdminCredentials_whenServeMethodIsCalled_thenDataIsReturned() throws IOException {
+        when(request.getParameter("user_name")).thenReturn("admin");
+        when(request.getParameter("user_pw")).thenReturn("123456");
+        when(request.getParameter("data_id")).thenReturn("1");
+        when(response.getWriter()).thenReturn(new PrintWriter(writer));
+
+        server.serve(request, response);
+
+        assertThat(writer.toString()).isEqualTo("Data[id=1, title=Title 1, description=Description 1]\nExternal data");
+    }
+
+    @Test
+    void givenMockedRequestWithUserCredentials_whenServeMethodIsCalled_thenNoDataIsReturned() throws IOException {
+        when(request.getParameter("user_name")).thenReturn("user");
+        when(request.getParameter("user_pw")).thenReturn("123456");
+
+        server.serve(request, response);
+
+        assertThat(writer.toString()).isEqualTo("");
+    }
+
+}
@@ -10,4 +10,7 @@ This module contains articles about Java 8 core features
 - [Interface With Default Methods vs Abstract Class](https://www.baeldung.com/java-interface-default-method-vs-abstract-class)
 - [Convert Between Byte Array and UUID in Java](https://www.baeldung.com/java-byte-array-to-uuid)
 - [Create a Simple “Rock-Paper-Scissors” Game in Java](https://www.baeldung.com/java-rock-paper-scissors)
+- [VarArgs vs Array Input Parameters in Java](https://www.baeldung.com/varargs-vs-array)
+- [Lambda Expression vs. Anonymous Inner Class](https://www.baeldung.com/java-lambdas-vs-anonymous-class)
+- [Java Helper vs. Utility Classes](https://www.baeldung.com/java-helper-vs-utility-classes)
 - [[<-- Prev]](/core-java-modules/core-java-8)
@@ -4,7 +4,6 @@
    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-8-2</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-8-2</name>
    <packaging>jar</packaging>

@@ -0,0 +1,40 @@
+package com.baeldung.helpervsutilityclasses;
+
+class MyHelperClass {
+    public double discount;
+    public MyHelperClass(double discount) {
+        if (discount > 0 && discount < 1) {
+            this.discount = discount;
+        }
+    }
+    public double discountedPrice(double price) {
+        return price - (price * discount);
+    }
+
+    public static int getMaxNumber(int[] numbers) {
+        if (numbers.length == 0) {
+            throw new IllegalArgumentException("Ensure array is not empty");
+        }
+        int max = numbers[0];
+        for (int i = 1; i < numbers.length; i++) {
+            if (numbers[i] > max) {
+                max = numbers[i];
+            }
+        }
+        return max;
+    }
+
+    public static int getMinNumber(int[] numbers) {
+        if (numbers.length == 0) {
+            throw new IllegalArgumentException("Ensure array is not empty");
+        }
+        int min = numbers[0];
+        for (int i = 1; i < numbers.length; i++) {
+            if (numbers[i] < min) {
+                min = numbers[i];
+            }
+        }
+        return min;
+    }
+
+}
@@ -0,0 +1,19 @@
+package com.baeldung.helpervsutilityclasses;
+
+public final class MyUtilityClass {
+
+    private MyUtilityClass(){}
+
+    public static String returnUpperCase(String stringInput) {
+        return stringInput.toUpperCase();
+    }
+
+    public static String returnLowerCase(String stringInput) {
+        return stringInput.toLowerCase();
+    }
+
+    public static String[] splitStringInput(String stringInput, String delimiter) {
+        return stringInput.split(delimiter);
+    }
+
+}
@@ -0,0 +1,20 @@
+package com.baeldung.helpervsutilityclasses;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class MyHelperClassUnitTest {
+
+    @Test
+    void whenCreatingHelperObject_thenHelperObjectShouldBeCreated() {
+        MyHelperClass myHelperClassObject = new MyHelperClass(0.10);
+        int[] numberArray = {15, 23, 66, 3, 51, 79};
+
+        assertNotNull(myHelperClassObject);
+
+        assertEquals(90, myHelperClassObject.discountedPrice(100.00));
+        assertEquals( 79, MyHelperClass.getMaxNumber(numberArray));
+        assertEquals(3, MyHelperClass.getMinNumber(numberArray));
+    }
+}
@@ -0,0 +1,15 @@
+package com.baeldung.helpervsutilityclasses;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class MyUtilityClassUnitTest {
+
+    @Test
+    void whenUsingUtilityMethods_thenAccessMethodsViaClassName(){
+        assertEquals( "INIUBONG", MyUtilityClass.returnUpperCase("iniubong"));
+        assertEquals("accra", MyUtilityClass.returnLowerCase("AcCrA"));
+    }
+
+}
@@ -2,4 +2,5 @@

 - [Generating Random Dates in Java](https://www.baeldung.com/java-random-dates)
 - [Creating a LocalDate with Values in Java](https://www.baeldung.com/java-creating-localdate-with-values)
- [[<-- Prev]](/core-java-modules/core-java-datetime-java8-1)
+- [Parsing Date Strings with Varying Formats](https://www.baeldung.com/java-parsing-dates-many-formats)
+- [[<-- Prev]](/core-java-modules/core-java-datetime-java8-1)
@@ -4,7 +4,6 @@
    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-8-datetime-2</artifactId>
-    <version>${project.parent.version}</version>
    <name>core-java-8-datetime-2</name>
    <packaging>jar</packaging>

@@ -0,0 +1,20 @@
+package com.baeldung.parsingDates;
+
+import java.util.Arrays;
+import java.util.List;
+import org.joda.time.LocalDate;
+import org.joda.time.format.DateTimeFormat;
+
+public class SimpleDateTimeFormat {
+
+    public static LocalDate parseDate(String date) {
+        List<String> patternList = Arrays.asList("MM/dd/yyyy", "dd.MM.yyyy", "yyyy-MM-dd");
+        for (String pattern : patternList) {
+            try {
+                return DateTimeFormat.forPattern(pattern).parseLocalDate(date);
+            } catch (IllegalArgumentException e) {
+            }
+        }
+        return null;
+    }
+}
@@ -0,0 +1,17 @@
+package com.baeldung.parsingDates;
+
+import java.time.LocalDate;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeFormatterBuilder;
+
+public class SimpleDateTimeFormater {
+
+    public static LocalDate parseDate(String date) {
+        DateTimeFormatterBuilder dateTimeFormatterBuilder = new DateTimeFormatterBuilder()
+                .append(DateTimeFormatter.ofPattern("[MM/dd/yyyy]" + "[dd-MM-yyyy]" + "[yyyy-MM-dd]"));
+
+        DateTimeFormatter dateTimeFormatter = dateTimeFormatterBuilder.toFormatter();
+
+        return LocalDate.parse(date, dateTimeFormatter);
+    }
+}
@@ -0,0 +1,18 @@
+package com.baeldung.parsingDates;
+
+import java.text.ParseException;
+import java.util.Date;
+import org.apache.commons.lang3.time.DateUtils;
+
+public class SimpleDateUtils {
+
+    public static Date parseDate(String date) {
+        try {
+            return DateUtils.parseDateStrictly(date,
+                    new String[]{"yyyy/MM/dd", "dd/MM/yyyy", "yyyy-MM-dd"});
+        } catch (ParseException ex) {
+            return null;
+        }
+    }
+
+}
@@ -0,0 +1,19 @@
+package com.baeldung.parsingDates;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.List;
+
+public class SimpleParseDate {
+
+    public Date parseDate(String dateString, List<String> formatStrings) {
+        for (String formatString : formatStrings) {
+            try {
+                return new SimpleDateFormat(formatString).parse(dateString);
+            } catch (ParseException e) {
+            }
+        }
+        return null;
+    }
+}
@@ -0,0 +1,43 @@
+package com.baeldung.parsingDates;
+
+import com.baeldung.parsingDates.SimpleDateTimeFormat;
+import com.baeldung.parsingDates.SimpleDateTimeFormater;
+import com.baeldung.parsingDates.SimpleDateUtils;
+import com.baeldung.parsingDates.SimpleParseDate;
+import java.time.format.DateTimeParseException;
+import java.util.Arrays;
+import org.junit.*;
+import static org.junit.Assert.*;
+import org.joda.time.LocalDate;
+
+public class SimpleParseDateUnitTest {
+
+    @Test
+    public void whenInvalidInput_thenGettingUnexpectedResult() {
+        SimpleParseDate simpleParseDate = new SimpleParseDate();
+        String date = "2022-40-40";
+        assertEquals("Sat May 10 00:00:00 UTC 2025", simpleParseDate.parseDate(date, Arrays.asList("MM/dd/yyyy", "dd.MM.yyyy", "yyyy-MM-dd")).toString());
+    }
+
+    @Test
+    public void whenInvalidDate_thenAssertThrows() {
+        SimpleDateTimeFormater simpleDateTimeFormater = new SimpleDateTimeFormater();
+        assertEquals(java.time.LocalDate.parse("2022-12-04"), simpleDateTimeFormater.parseDate("2022-12-04"));
+        assertThrows(DateTimeParseException.class, () -> simpleDateTimeFormater.parseDate("2022-13-04"));
+    }
+
+    @Test
+    public void whenDateIsCorrect_thenParseCorrect() {
+        SimpleDateUtils simpleDateUtils = new SimpleDateUtils();
+        assertNull(simpleDateUtils.parseDate("53/10/2014"));
+        assertEquals("Wed Sep 10 00:00:00 UTC 2014", simpleDateUtils.parseDate("10/09/2014").toString());
+    }
+
+    @Test
+    public void whenDateIsCorrect_thenResultCorrect() {
+        SimpleDateTimeFormat simpleDateTimeFormat = new SimpleDateTimeFormat();
+        assertNull(simpleDateTimeFormat.parseDate("53/10/2014"));
+        assertEquals(LocalDate.parse("2014-10-10"), simpleDateTimeFormat.parseDate("2014-10-10"));
+    }
+
+}
@@ -4,7 +4,6 @@
    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-8-datetime</artifactId>
-    <version>${project.parent.version}</version>
    <name>core-java-8-datetime</name>
    <packaging>jar</packaging>

@@ -4,7 +4,6 @@
    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-8</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-8</name>
    <packaging>jar</packaging>

@@ -4,7 +4,6 @@
    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-9-improvements</artifactId>
-    <version>0.2-SNAPSHOT</version>
    <name>core-java-9-improvements</name>

    <parent>
@@ -8,5 +8,5 @@ This module contains articles about Project Jigsaw and the Java Platform Module
 - [A Guide to Java 9 Modularity](https://www.baeldung.com/java-9-modularity)
 - [Java 9 java.lang.Module API](https://www.baeldung.com/java-9-module-api)
 - [Java 9 Illegal Reflective Access Warning](https://www.baeldung.com/java-illegal-reflective-access)
-
+- [Java Modularity and Unit Testing](https://www.baeldung.com/java-modularity-unit-testing)

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+javac -d mods/com.baeldung.library.core $(find library-core/src/main -name "*.java")
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+javac --class-path outDir/library-core/:\
+libs/junit-jupiter-engine-5.9.2.jar:\
+libs/junit-platform-engine-1.9.2.jar:\
+libs/apiguardian-api-1.1.2.jar:\
+libs/junit-jupiter-params-5.9.2.jar:\
+libs/junit-jupiter-api-5.9.2.jar:\
+libs/opentest4j-1.2.0.jar:\
+libs/junit-platform-commons-1.9.2.jar \
+-d outDir/library-test library-core/src/test/java/com/baeldung/library/core/LibraryUnitTest.java
@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+javac --class-path libs/junit-jupiter-engine-5.9.2.jar:\
+libs/junit-platform-engine-1.9.2.jar:\
+libs/apiguardian-api-1.1.2.jar:\
+libs/junit-jupiter-params-5.9.2.jar:\
+libs/junit-jupiter-api-5.9.2.jar:\
+libs/opentest4j-1.2.0.jar:\
+libs/junit-platform-commons-1.9.2.jar \
+-d outDir/library-core \
+library-core/src/main/java/com/baeldung/library/core/Book.java \
+library-core/src/main/java/com/baeldung/library/core/Library.java \
+library-core/src/main/java/com/baeldung/library/core/Main.java \
+library-core/src/test/java/com/baeldung/library/core/LibraryUnitTest.java
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+javac --class-path libs/junit-jupiter-engine-5.9.2.jar:\
+libs/junit-platform-engine-1.9.2.jar:\
+libs/apiguardian-api-1.1.2.jar:\
+libs/junit-jupiter-params-5.9.2.jar:\
+libs/junit-jupiter-api-5.9.2.jar:\
+libs/opentest4j-1.2.0.jar:\
+libs/junit-platform-commons-1.9.2.jar \
+-d outDir/library-core \
+library-core/src/main/java/com/baeldung/library/core/Book.java \
+library-core/src/main/java/com/baeldung/library/core/Library.java \
+library-core/src/main/java/com/baeldung/library/core/Main.java
@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+javac --module-path mods:libs -d mods/com.baeldung.library.test $(find library-test/src/test -name "*.java")
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+wget -P libs/ https://repo1.maven.org/maven2/org/apiguardian/apiguardian-api/1.1.2/apiguardian-api-1.1.2.jar /
+wget -P libs/ https://repo1.maven.org/maven2/org/opentest4j/opentest4j/1.2.0/opentest4j-1.2.0.jar /
+wget -P libs/ https://repo1.maven.org/maven2/org/junit/platform/junit-platform-commons/1.9.2/junit-platform-commons-1.9.2.jar /
+wget -P libs/ https://repo1.maven.org/maven2/org/junit/platform/junit-platform-engine/1.9.2/junit-platform-engine-1.9.2.jar /
+wget -P libs/ https://repo1.maven.org/maven2/org/junit/platform/junit-platform-reporting/1.9.2/junit-platform-reporting-1.9.2.jar /
+wget -P libs/ https://repo1.maven.org/maven2/org/junit/platform/junit-platform-console/1.9.2/junit-platform-console-1.9.2.jar /
+wget -P libs/ https://repo1.maven.org/maven2/org/junit/platform/junit-platform-launcher/1.9.2/junit-platform-launcher-1.9.2.jar /
+wget -P libs/ https://repo1.maven.org/maven2/org/junit/jupiter/junit-jupiter-engine/5.9.2/junit-jupiter-engine-5.9.2.jar /
+wget -P libs/ https://repo1.maven.org/maven2/org/junit/jupiter/junit-jupiter-params/5.9.2/junit-jupiter-params-5.9.2.jar
@@ -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>
+  <parent>
+    <groupId>com.baeldung</groupId>
+    <artifactId>core-java-9-jigsaw</artifactId>
+    <version>0.2-SNAPSHOT</version>
+  </parent>
+
+  <artifactId>library-core</artifactId>
+
+  <properties>
+    <maven.compiler.source>19</maven.compiler.source>
+    <maven.compiler.target>19</maven.compiler.target>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-api</artifactId>
+      <version>5.9.2</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <version>5.9.2</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.8.1</version>
+        <configuration>
+          <release>9</release>
+        </configuration>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.0.0-M5</version>
+        <configuration>
+          <useModulePath>false</useModulePath>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>
@@ -0,0 +1,52 @@
+package com.baeldung.library.core;
+
+import java.util.Objects;
+
+public class Book {
+
+    private String title;
+    private String author;
+
+    public Book(String title, String author) {
+        this.title = title;
+        this.author = author;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+
+    @Override
+    public String toString() {
+        return "Book [title=" + title + ", author=" + author + "]";
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+
+        final Book book = (Book) o;
+
+        if (!Objects.equals(title, book.title)) {
+            return false;
+        }
+        return Objects.equals(author, book.author);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = title != null ? title.hashCode() : 0;
+        result = 31 * result + (author != null ? author.hashCode() : 0);
+        return result;
+    }
+}
@@ -0,0 +1,25 @@
+package com.baeldung.library.core;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Library {
+
+    private List<Book> books = new ArrayList<>();
+
+    public void addBook(Book book) {
+        books.add(book);
+    }
+
+    public List<Book> getBooks() {
+        return books;
+    }
+
+    void removeBook(Book book) {
+        books.remove(book);
+    }
+
+    protected void removeBookByAuthor(String author) {
+        books.removeIf(book -> book.getAuthor().equals(author));
+    }
+}
@@ -0,0 +1,16 @@
+package com.baeldung.library.core;
+
+public class Main {
+
+    public static void main(String[] args) {
+        Library library = new Library();
+        library.addBook(new Book("The Lord of the Rings", "J.R.R. Tolkien"));
+        library.addBook(new Book("The Hobbit", "J.R.R. Tolkien"));
+        library.addBook(new Book("The Silmarillion", "J.R.R. Tolkien"));
+        library.addBook(new Book("The Chronicles of Narnia", "C.S. Lewis"));
+        library.addBook(new Book("The Lion, the Witch and the Wardrobe", "C.S. Lewis"));
+        System.out.println("Welcome to our library!");
+        System.out.println("We have the following books:");
+        library.getBooks().forEach(System.out::println);
+    }
+}
@@ -0,0 +1,3 @@
+module com.baeldung.library.core {
+    exports com.baeldung.library.core;
+}
@@ -0,0 +1,47 @@
+package com.baeldung.library.core;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class LibraryUnitTest {
+
+    @Test
+    void givenEmptyLibrary_whenAddABook_thenLibraryHasOneBook() {
+        Library library = new Library();
+        Book theLordOfTheRings = new Book("The Lord of the Rings", "J.R.R. Tolkien");
+        library.addBook(theLordOfTheRings);
+        int expected = 1;
+        int actual = library.getBooks().size();
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void givenTheLibraryWithABook_whenRemoveABook_thenLibraryIsEmpty() {
+        Library library = new Library();
+        Book theLordOfTheRings = new Book("The Lord of the Rings", "J.R.R. Tolkien");
+        library.addBook(theLordOfTheRings);
+        library.removeBook(theLordOfTheRings);
+        int expected = 0;
+        int actual = library.getBooks().size();
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void givenTheLibraryWithSeveralBook_whenRemoveABookByAuthor_thenLibraryHasNoBooksByTheAuthor() {
+        Library library = new Library();
+        Book theLordOfTheRings = new Book("The Lord of the Rings", "J.R.R. Tolkien");
+        Book theHobbit = new Book("The Hobbit", "J.R.R. Tolkien");
+        Book theSilmarillion = new Book("The Silmarillion", "J.R.R. Tolkien");
+        Book theHungerGames = new Book("The Hunger Games", "Suzanne Collins");
+        library.addBook(theLordOfTheRings);
+        library.addBook(theHobbit);
+        library.addBook(theSilmarillion);
+        library.addBook(theHungerGames);
+        library.removeBookByAuthor("J.R.R. Tolkien");
+        int expected = 1;
+        int actual = library.getBooks().size();
+        assertEquals(expected, actual);
+    }
+
+}
@@ -0,0 +1,53 @@
+package com.baeldung.library.test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.baeldung.library.core.Book;
+import com.baeldung.library.core.Library;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import org.junit.jupiter.api.Test;
+
+class LibraryUnitTest {
+
+    @Test
+    void givenEmptyLibrary_whenAddABook_thenLibraryHasOneBook() {
+        Library library = new Library();
+        Book theLordOfTheRings = new Book("The Lord of the Rings", "J.R.R. Tolkien");
+        library.addBook(theLordOfTheRings);
+        int expected = 1;
+        int actual = library.getBooks().size();
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void givenTheLibraryWithABook_whenRemoveABook_thenLibraryIsEmpty()
+        throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
+        Library library = new Library();
+        Book theLordOfTheRings = new Book("The Lord of the Rings", "J.R.R. Tolkien");
+        library.addBook(theLordOfTheRings);
+        Method removeBook = Library.class.getDeclaredMethod("removeBook", Book.class);
+        removeBook.setAccessible(true);
+        removeBook.invoke(library, theLordOfTheRings);
+        int expected = 0;
+        int actual = library.getBooks().size();
+        assertEquals(expected, actual);
+    }
+@Test
+void givenTheLibraryWithSeveralBook_whenRemoveABookByAuthor_thenLibraryHasNoBooksByTheAuthor() {
+    TestLibrary library = new TestLibrary();
+    Book theLordOfTheRings = new Book("The Lord of the Rings", "J.R.R. Tolkien");
+    Book theHobbit = new Book("The Hobbit", "J.R.R. Tolkien");
+    Book theSilmarillion = new Book("The Silmarillion", "J.R.R. Tolkien");
+    Book theHungerGames = new Book("The Hunger Games", "Suzanne Collins");
+    library.addBook(theLordOfTheRings);
+    library.addBook(theHobbit);
+    library.addBook(theSilmarillion);
+    library.addBook(theHungerGames);
+    library.removeBookByAuthor("J.R.R. Tolkien");
+    int expected = 1;
+    int actual = library.getBooks().size();
+    assertEquals(expected, actual);
+}
+
+}
@@ -0,0 +1,10 @@
+package com.baeldung.library.test;
+
+import com.baeldung.library.core.Library;
+
+public class TestLibrary extends Library {
+    @Override
+    public void removeBookByAuthor(final String author) {
+        super.removeBookByAuthor(author);
+    }
+}
@@ -0,0 +1,5 @@
+module com.baeldung.library.test {
+    requires com.baeldung.library.core;
+    requires org.junit.jupiter.api;
+    opens com.baeldung.library.test to org.junit.platform.commons;
+}
@@ -4,8 +4,11 @@
    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-9-jigsaw</artifactId>
-    <version>0.2-SNAPSHOT</version>
    <name>core-java-9-jigsaw</name>
+    <packaging>pom</packaging>
+    <modules>
+        <module>library-core</module>
+    </modules>

    <parent>
        <groupId>com.baeldung</groupId>
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+java --module-path mods:libs \
+--add-modules com.baeldung.library.core \
+--add-opens com.baeldung.library.core/com.baeldung.library.core=org.junit.platform.commons \
+--add-reads com.baeldung.library.core=org.junit.jupiter.api \
+--patch-module com.baeldung.library.core=outDir/library-test \
+--module org.junit.platform.console --select-class com.baeldung.library.core.LibraryUnitTest
@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+java --module-path mods --module com.baeldung.library.core/com.baeldung.library.core.Main
@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+java --module-path libs \
+org.junit.platform.console.ConsoleLauncher \
+--classpath ./outDir/library-core \
+--select-class com.baeldung.library.core.LibraryUnitTest
@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+java --module-path mods:libs \
+--add-modules com.baeldung.library.test \
+--add-opens com.baeldung.library.core/com.baeldung.library.core=com.baeldung.library.test \
+org.junit.platform.console.ConsoleLauncher --select-class com.baeldung.library.test.LibraryUnitTest
@@ -4,7 +4,6 @@
    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-9-new-features</artifactId>
-    <version>0.2-SNAPSHOT</version>
    <name>core-java-9-new-features</name>

    <parent>
@@ -4,7 +4,6 @@
    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-9-streams</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-9-streams</name>
    <packaging>jar</packaging>

@@ -5,7 +5,6 @@ This module contains articles about Java 9 core features
 ### Relevant Articles:

 - [Method Handles in Java](https://www.baeldung.com/java-method-handles)
- [Introduction to Chronicle Queue](https://www.baeldung.com/java-chronicle-queue)
 - [Iterate Through a Range of Dates in Java](https://www.baeldung.com/java-iterate-date-range)
 - [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)
 - [Immutable ArrayList in Java](https://www.baeldung.com/java-immutable-list)
@@ -4,7 +4,6 @@
    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-9</artifactId>
-    <version>0.2-SNAPSHOT</version>
    <name>core-java-9</name>

    <parent>
@@ -4,7 +4,6 @@
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <artifactId>core-java-annotations</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-annotations</name>
    <packaging>jar</packaging>

@@ -24,4 +23,12 @@
        </resources>
    </build>

+    <dependencies>
+        <dependency>
+            <groupId>javax.annotation</groupId>
+            <artifactId>javax.annotation-api</artifactId>
+            <version>1.3.2</version>
+        </dependency>
+    </dependencies>
+
 </project>
@@ -17,7 +17,7 @@ public class ClassWithSuppressWarningsNames implements Serializable {
        list.add(Integer.valueOf(value));
    }

-    @SuppressWarnings("deprecated")
+    @SuppressWarnings("deprecation")
    void suppressDeprecatedWarning() {
        ClassWithSuppressWarningsNames cls = new ClassWithSuppressWarningsNames();
        cls.deprecatedMethod(); // no warning here
@@ -11,3 +11,5 @@ This module contains articles about Java array fundamentals. They assume no prev
 - [Removing the First Element of an Array](https://www.baeldung.com/java-array-remove-first-element)
 - [Extending an Array’s Length](https://www.baeldung.com/java-array-add-element-at-the-end)
 - [Initializing a Boolean Array in Java](https://www.baeldung.com/java-initializing-boolean-array)
+- [Find the Index of an Element in a Java Array](https://www.baeldung.com/java-array-find-index)
+- [Comparing Two Byte Arrays in Java](https://www.baeldung.com/java-comparing-byte-arrays)
@@ -0,0 +1,28 @@
+package com.baeldung.arrayindex;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.IntStream;
+
+class ArrayIndex {
+    static int forLoop(int[] numbers, int target) {
+        for (int index = 0; index < numbers.length; index++) {
+            if (numbers[index] == target) {
+                return index;
+            }
+        }
+        return -1;
+    }
+
+    static int listIndexOf(Integer[] numbers, int target) {
+        List<Integer> list = Arrays.asList(numbers);
+        return list.indexOf(target);
+    }
+
+    static int intStream(int[] numbers, int target) {
+        return IntStream.range(0, numbers.length)
+          .filter(i -> numbers[i] == target)
+          .findFirst()
+          .orElse(-1);
+    }
+}
@@ -0,0 +1,39 @@
+package com.baeldung.array.compare;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+
+import org.junit.jupiter.api.Test;
+
+public class CompareByteArraysUnitTest {
+    private final static String INPUT = "I am a magic string.";
+    private final static byte[] ARRAY1 = INPUT.getBytes();
+    private final static byte[] ARRAY2 = INPUT.getBytes();
+
+    @Test
+    void whenUsingEqualsSign_thenTwoArraysAreNotEqual() {
+        assertFalse(ARRAY1 == ARRAY2);
+    }
+
+    @Test
+    void whenUsingEquals_thenTwoArraysAreNotEqual() {
+        assertFalse(ARRAY1.equals(ARRAY2));
+    }
+
+    @Test
+    void whenUsingArrayEquals_thenTwoArraysAreEqual() {
+        assertTrue(Arrays.equals(ARRAY1, ARRAY2));
+    }
+
+    @Test
+    void whenComparingStringArrays_thenGetExpectedResult() {
+        String[] strArray1 = new String[] { "Java", "is", "great" };
+        String[] strArray2 = new String[] { "Java", "is", "great" };
+
+        assertFalse(strArray1 == strArray2);
+        assertFalse(strArray1.equals(strArray2));
+        assertTrue(Arrays.equals(strArray1, strArray2));
+    }
+}
@@ -0,0 +1,106 @@
+package com.baeldung.arrayindex;
+
+import static com.baeldung.arrayindex.ArrayIndex.forLoop;
+import static com.baeldung.arrayindex.ArrayIndex.intStream;
+import static com.baeldung.arrayindex.ArrayIndex.listIndexOf;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+
+import org.apache.commons.lang3.ArrayUtils;
+import org.junit.jupiter.api.Test;
+
+import com.google.common.primitives.Ints;
+
+class ArrayIndexUnitTest {
+
+    @Test
+    void givenIntegerArray_whenUseForLoop_thenWillGetElementIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(2, forLoop(numbers, 30));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseForLoop_thenWillGetElementMinusOneIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(-1, forLoop(numbers, 100));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseIndexOf_thenWillGetElementIndex() {
+        Integer[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(2, listIndexOf(numbers, 30));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseIndexOf_thenWillGetElementMinusOneIndex() {
+        Integer[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(-1, listIndexOf(numbers, 100));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseIntStream_thenWillGetElementIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(2, intStream(numbers, 30));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseIntStream_thenWillGetElementMinusOneIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(-1, intStream(numbers, 100));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseBinarySearch_thenWillGetElementIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(2, Arrays.binarySearch(numbers, 30));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseBinarySearch_thenWillGetUpperBoundMinusIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(-6, Arrays.binarySearch(numbers, 100));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseBinarySearch_thenWillGetInArrayMinusIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(-2, Arrays.binarySearch(numbers, 15));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseBinarySearch_thenWillGetLowerBoundMinusIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(-1, Arrays.binarySearch(numbers, -15));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseApacheCommons_thenWillGetElementIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(2, ArrayUtils.indexOf(numbers, 30));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseApacheCommonsStartingFromIndex_thenWillGetNegativeIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(-1, ArrayUtils.indexOf(numbers, 30, 3));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseApacheCommons_thenWillGetElementMinusOneIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(-1, ArrayUtils.indexOf(numbers, 100));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseGuavaInts_thenWillGetElementIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(2, Ints.indexOf(numbers, 30));
+    }
+
+    @Test
+    void givenIntegerArray_whenUseGuavaInts_thenWillGetElementMinusOneIndex() {
+        int[] numbers = { 10, 20, 30, 40, 50 };
+        assertEquals(-1, Ints.indexOf(numbers, 100));
+    }
+}
@@ -0,0 +1,6 @@
+## Core Java Booleans
+
+This module contains articles about Java Booleans.
+
+### Relevant Articles: 
+- [Convert Boolean to String in Java](https://www.baeldung.com/java-convert-boolean-to-string)
@@ -0,0 +1,16 @@
+<?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-booleans</artifactId>
+    <name>core-java-booleans</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+</project>
@@ -0,0 +1,48 @@
+package com.baeldung.booleans;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class BooleanToStringUnitTest {
+    String optionToString(String optionName, boolean optionValue) {
+        return String.format("The option '%s' is %s.", optionName, optionValue ? "Enabled" : "Disabled");
+    }
+
+    @Test
+    void givenPrimitiveBoolean_whenConvertingUsingTernaryOperator_thenSuccess() {
+        boolean primitiveBoolean = true;
+        assertEquals("true", primitiveBoolean ? "true" : "false");
+
+        primitiveBoolean = false;
+        assertEquals("false", primitiveBoolean ? "true" : "false");
+
+        assertEquals("The option 'IgnoreWarnings' is Enabled.", optionToString("IgnoreWarnings", true));
+    }
+
+
+    @Test
+    void givenBooleanObject_whenConvertingUsingBooleanToString_thenSuccess() {
+        Boolean myBoolean = Boolean.TRUE;
+        assertEquals("true", myBoolean.toString());
+
+        myBoolean = Boolean.FALSE;
+        assertEquals("false", myBoolean.toString());
+
+        Boolean nullBoolean = null;
+        assertThrows(NullPointerException.class, () -> nullBoolean.toString());
+    }
+
+    @Test
+    void givenBooleanObject_whenConvertingUsingStringValueOf_thenSuccess() {
+        Boolean myBoolean = Boolean.TRUE;
+        assertEquals("true", String.valueOf(myBoolean));
+
+        myBoolean = Boolean.FALSE;
+        assertEquals("false", String.valueOf(myBoolean));
+
+        Boolean nullBoolean = null;
+        assertEquals("null", String.valueOf(nullBoolean));
+    }
+}
@@ -4,3 +4,4 @@ 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)
@@ -4,7 +4,6 @@
    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-char</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-char</name>
    <packaging>jar</packaging>

@@ -0,0 +1,56 @@
+package com.baeldung.charandstring;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+
+import org.junit.jupiter.api.Test;
+
+public class DifferenceBetweenCharAndStringUnitTest {
+
+    @Test
+    void whenPlusTwoChars_thenGetSumAsInteger() {
+        char h = 'H'; // the value is 72
+        char i = 'i'; // the value is 105
+        assertEquals(177, h + i);
+        assertInstanceOf(Integer.class, h + i);
+    }
+
+    @Test
+    void whenPlusTwoStrings_thenConcatenateThem() {
+        String i = "i";
+        String h = "H";
+        assertEquals("Hi", h + i);
+    }
+
+    @Test
+    void whenPlusCharsAndStrings_thenGetExpectedValues() {
+        char c = 'C';
+        assertEquals("C", "" + c);
+
+        char h = 'H'; // the value is 72
+        char i = 'i'; // the value is 105
+        assertEquals("Hi", "" + h + i);
+        assertEquals("Hi", h + "" + i);
+        assertEquals("177", h + i + "");
+    }
+
+    @Test
+    void whenStringChars_thenGetCharArray() {
+        char h = 'h';
+        char e = 'e';
+        char l = 'l';
+        char o = 'o';
+
+        String hello = "hello";
+        assertEquals(h, hello.charAt(0));
+        assertEquals(e, hello.charAt(1));
+        assertEquals(l, hello.charAt(2));
+        assertEquals(l, hello.charAt(3));
+        assertEquals(o, hello.charAt(4));
+
+        char[] chars = new char[] { h, e, l, l, o };
+        char[] charsFromString = hello.toCharArray();
+        assertArrayEquals(chars, charsFromString);
+    }
+}
@@ -13,4 +13,4 @@
 - [Getting the Size of an Iterable in Java](https://www.baeldung.com/java-iterable-size)
 - [Java Null-Safe Streams from Collections](https://www.baeldung.com/java-null-safe-streams-from-collections)
 - [Differences Between Iterator and Iterable and How to Use Them?](https://www.baeldung.com/java-iterator-vs-iterable)
- More articles: [[<-- prev]](/core-java-modules/core-java-collections-1) [[next -->]](/core-java-modules/core-java-collections-3)
+- More articles: [[<-- prev]](/core-java-modules/core-java-collections) [[next -->]](/core-java-modules/core-java-collections-3)
@@ -4,7 +4,6 @@
    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-3</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-collections-3</name>
    <packaging>jar</packaging>

@@ -4,7 +4,6 @@
    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-4</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
    <name>core-java-collections-4</name>
    <packaging>jar</packaging>

@@ -3,5 +3,5 @@
 ## Core Java Collections Cookbooks and Examples

 ### Relevant Articles:
-
- More articles: [[<-- prev]](/core-java-modules/core-java-collections-4)
+- [Introduction to Roaring Bitmap](https://www.baeldung.com/java-roaring-bitmap-intro)
+- More articles: [[<-- prev]](/core-java-modules/core-java-collections-4)
@@ -1,10 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <artifactId>core-java-collections-5</artifactId>
-    <version>0.0.1-SNAPSHOT</version>
    <name>core-java-collections-5</name>
    <packaging>jar</packaging>

@@ -55,4 +54,5 @@
        <roaringbitmap.version>0.9.38</roaringbitmap.version>
        <jmh.version>1.36</jmh.version>
    </properties>
+    
 </project>
--- a/Show More
+++ b/Show More