Merge branch 'master' into study-groovy

README.md

@@ -72,6 +72,13 @@ Building a single module
 To build a specific module, run the command: `mvn clean install` in the module directory.
 
 
+Building modules from the root of the repository
+====================
+To build specific modules from the root of the repository, run the command: `mvn clean install --pl asm,atomikos -Pdefault-first` in the root directory.
+
+Here `asm` and `atomikos` are the modules that we want to build and `default-first` is the maven profile in which these modules are present.
+
+
 Running a Spring Boot module
 ====================
 To run a Spring Boot module, run the command: `mvn spring-boot:run` in the module directory.

apache-httpclient-2/src/test/java/com/baeldung/httpclient/cookies/HttpClientGettingCookieValueUnitTest.java

@@ -1,36 +1,41 @@
 package com.baeldung.httpclient.cookies;
 
-import org.apache.http.client.CookieStore;
+import static org.junit.jupiter.api.Assertions.assertEquals;
-import org.apache.http.client.methods.CloseableHttpResponse;
+
-import org.apache.http.client.methods.HttpGet;
+import org.apache.hc.client5.http.classic.methods.HttpGet;
-import org.apache.http.client.protocol.HttpClientContext;
+import org.apache.hc.client5.http.cookie.BasicCookieStore;
-import org.apache.http.cookie.ClientCookie;
+import org.apache.hc.client5.http.cookie.Cookie;
-import org.apache.http.cookie.Cookie;
+import org.apache.hc.client5.http.cookie.CookieStore;
-import org.apache.http.impl.client.BasicCookieStore;
+
-import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.hc.client5.http.impl.classic.BasicHttpClientResponseHandler;
-import org.apache.http.impl.client.HttpClients;
+import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
-import org.apache.http.impl.cookie.BasicClientCookie;
+import org.apache.hc.client5.http.impl.classic.HttpClientBuilder;
+
+import org.apache.hc.client5.http.impl.cookie.BasicClientCookie;
+import org.apache.hc.client5.http.protocol.HttpClientContext;
+
 import org.junit.jupiter.api.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
 
-import static org.junit.Assert.assertEquals;
+class HttpClientGettingCookieValueUnitTest {
-
-
-public class HttpClientGettingCookieValueUnitTest {
     private static Logger log = LoggerFactory.getLogger(HttpClientGettingCookieValueUnitTest.class);
 
     private static final String SAMPLE_URL = "http://www.baeldung.com/";
 
     @Test
-    public final void whenSettingCustomCookieOnTheRequest_thenGettingTheSameCookieFromTheResponse() throws IOException {
+    void whenSettingCustomCookieOnTheRequest_thenGettingTheSameCookieFromTheResponse() throws IOException {
+
         HttpClientContext context = HttpClientContext.create();
         context.setAttribute(HttpClientContext.COOKIE_STORE, createCustomCookieStore());
 
-        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
+        final HttpGet request = new HttpGet(SAMPLE_URL);
-            try (CloseableHttpResponse response = httpClient.execute(new HttpGet(SAMPLE_URL), context)) {
+
+        try (CloseableHttpClient client = HttpClientBuilder.create()
+            .build()) {
+            client.execute(request, context, new BasicHttpClientResponseHandler());
             CookieStore cookieStore = context.getCookieStore();
             Cookie customCookie = cookieStore.getCookies()
                 .stream()
@@ -42,13 +47,12 @@ public class HttpClientGettingCookieValueUnitTest {
             assertEquals("test_value", customCookie.getValue());
         }
     }
-    }
 
     private BasicCookieStore createCustomCookieStore() {
         BasicCookieStore cookieStore = new BasicCookieStore();
         BasicClientCookie cookie = new BasicClientCookie("custom_cookie", "test_value");
         cookie.setDomain("baeldung.com");
-        cookie.setAttribute(ClientCookie.DOMAIN_ATTR, "true");
+        cookie.setAttribute("domain", "true");
         cookie.setPath("/");
         cookieStore.addCookie(cookie);
         return cookieStore;

core-java-modules/core-java-8/README.md

@@ -11,4 +11,5 @@ This module contains articles about Java 8 core features
 - [Finding Min/Max in an Array with Java](https://www.baeldung.com/java-array-min-max)
 - [Internationalization and Localization in Java 8](https://www.baeldung.com/java-8-localization)
 - [Generalized Target-Type Inference in Java](https://www.baeldung.com/java-generalized-target-type-inference)
+- [Monads in Java](https://www.baeldung.com/java-monads)
 - [[More -->]](/core-java-modules/core-java-8-2)

core-java-modules/core-java-8/src/main/java/com/baeldung/monad/MonadSamples.java

@@ -28,30 +28,16 @@ class MonadSample1 extends MonadBaseExample {
     public double apply(double n) {
         return subtract1(add3(divideBy2(multiplyBy2(multiplyBy2(2)))));
     }
-
-    public static void main(String[] args) {
-        final MonadSample1 test = new MonadSample1();
-        System.out.println(test.apply(2));
-        //6.0
-    }
-
 }
 
 class MonadSample2 extends MonadBaseExample {
     public double apply(double n) {
-        final double n1 = multiplyBy2(n);
+        double n1 = multiplyBy2(n);
-        final double n2 = multiplyBy2(n1);
+        double n2 = multiplyBy2(n1);
-        final double n3 = divideBy2(n2);
+        double n3 = divideBy2(n2);
-        final double n4 = add3(n3);
+        double n4 = add3(n3);
         return subtract1(n4);
     }
-
-    public static void main(String[] args) {
-        final MonadSample2 test = new MonadSample2();
-        System.out.println(test.apply(2));
-        //6.0
-    }
-
 }
 
 class MonadSample3 extends MonadBaseExample {
@@ -66,11 +52,6 @@ class MonadSample3 extends MonadBaseExample {
                 .get();
     }
 
-    public static void main(String[] args) {
-        final MonadSample3 test = new MonadSample3();
-        System.out.println(test.apply(2));
-        //6.0
-    }
 }
 
  class MonadSample4 extends MonadBaseExample {
@@ -90,13 +71,6 @@ class MonadSample3 extends MonadBaseExample {
          return leftSide.equals(rightSide);
      }
 
-     public static void main(String[] args) {
-         final MonadSample4 test = new MonadSample4();
-
-         System.out.println(test.leftIdentity()); //true
-         System.out.println(test.rightIdentity()); //true
-         System.out.println(test.associativity()); //true
-     }
  }
 
 class MonadSample5 extends MonadBaseExample {
@@ -104,10 +78,5 @@ class MonadSample5 extends MonadBaseExample {
         Function<Integer, Optional<Integer>> mapping = value -> Optional.of(value == null ? -1 : value + 1);
         return Optional.ofNullable((Integer) null).flatMap(mapping).equals(mapping.apply(null));
     }
-
-    public static void main(String[] args) {
-        final MonadSample5 test = new MonadSample5();
-        System.out.println(test.fail());
-    }
 }
 

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

@@ -9,3 +9,6 @@ This module contains articles about the Java ArrayList collection
 - [Multi Dimensional ArrayList in Java](https://www.baeldung.com/java-multi-dimensional-arraylist)
 - [Removing an Element From an ArrayList](https://www.baeldung.com/java-arraylist-remove-element)
 - [The Capacity of an ArrayList vs the Size of an Array in Java](https://www.baeldung.com/java-list-capacity-array-size)
+- [Case-Insensitive Searching in ArrayList](https://www.baeldung.com/java-arraylist-case-insensitive-search)
+- [Storing Data Triple in a List in Java](https://www.baeldung.com/java-list-storing-triple)
+- [Convert an ArrayList of Object to an ArrayList of String Elements](https://www.baeldung.com/java-object-list-to-strings)

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

@@ -5,6 +5,33 @@
     <modelVersion>4.0.0</modelVersion>
     <artifactId>core-java-collections-array-list</artifactId>
     <version>0.1.0-SNAPSHOT</version>
+    <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>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>${surefire.plugin.version}</version>
+                <configuration>
+                    <argLine>
+                        --add-opens java.base/java.util=ALL-UNNAMED
+                    </argLine>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+    <properties>
+        <maven-compiler-plugin.source>16</maven-compiler-plugin.source>
+        <maven-compiler-plugin.target>16</maven-compiler-plugin.target>
+        <surefire.plugin.version>3.0.0-M3</surefire.plugin.version>
+    </properties>
     <name>core-java-collections-array-list</name>
     <packaging>jar</packaging>
 
@@ -20,6 +47,12 @@
             <artifactId>commons-collections4</artifactId>
             <version>${commons-collections4.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>31.1-jre</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
 </project>

core-java-modules/core-java-collections-array-list/src/main/java/com/baeldung/list/ignorecase/IgnoreCaseSearchUtil.java

@@ -0,0 +1,14 @@
+package com.baeldung.list.ignorecase;
+
+import java.util.List;
+
+public class IgnoreCaseSearchUtil {
+    public static boolean ignoreCaseContains(List<String> theList, String searchStr) {
+        for (String s : theList) {
+            if (searchStr.equalsIgnoreCase(s)) {
+                return true;
+            }
+        }
+        return false;
+    }
+}

core-java-modules/core-java-collections-array-list/src/main/java/com/baeldung/list/ignorecase/IgnoreCaseStringList.java

@@ -0,0 +1,29 @@
+package com.baeldung.list.ignorecase;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+public class IgnoreCaseStringList extends ArrayList<String> {
+
+    public IgnoreCaseStringList() {
+
+    }
+
+    public IgnoreCaseStringList(Collection<? extends String> c) {
+        super(c);
+    }
+
+    @Override
+    public boolean contains(Object o) {
+        String searchStr = (String) o;
+        // Using Stream API:
+        // return this.stream().anyMatch(searchStr::equalsIgnoreCase);
+        for (String s : this) {
+            if (searchStr.equalsIgnoreCase(s)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+}

core-java-modules/core-java-collections-array-list/src/main/java/com/baeldung/listofobjectstolistofstring/Node.java

@@ -0,0 +1,17 @@
+package com.baeldung.listofobjectstolistofstring;
+
+public class Node {
+
+    private final int x;
+    private final int y;
+
+    public Node(int x, int y) {
+        this.x = x;
+        this.y = y;
+    }
+
+    @Override
+    public String toString() {
+        return "Node (" + "x=" + x + ", y=" + y + ')';
+    }
+}

core-java-modules/core-java-collections-array-list/src/main/java/com/baeldung/listofobjectstolistofstring/User.java

@@ -0,0 +1,14 @@
+package com.baeldung.listofobjectstolistofstring;
+
+public class User {
+    private final String fullName;
+
+    public User(String fullName) {
+        this.fullName = fullName;
+    }
+
+    @Override
+    public String toString() {
+        return "User (" + "full name='" + fullName + ')';
+    }
+}

core-java-modules/core-java-collections-array-list/src/main/java/com/baeldung/triple/Triple.java

@@ -0,0 +1,26 @@
+package com.baeldung.triple;
+
+public class Triple<L, M, R> {
+
+    private final L left;
+    private final M middle;
+    private final R right;
+
+    public Triple(L left, M middle, R right) {
+        this.left = left;
+        this.middle = middle;
+        this.right = right;
+    }
+
+    public L getLeft() {
+        return left;
+    }
+
+    public M getMiddle() {
+        return middle;
+    }
+
+    public R getRight() {
+        return right;
+    }
+}

core-java-modules/core-java-collections-array-list/src/test/java/com/baeldung/list/ignorecase/IgnoreCaseContainsUnitTest.java

@@ -0,0 +1,45 @@
+package com.baeldung.list.ignorecase;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class IgnoreCaseContainsUnitTest {
+    private static final List<String> LANGUAGES = Arrays.asList("Java", "Python", "Kotlin", "Ruby", "Javascript", "Go");
+
+    @Test
+    void givenStringList_whenCallTheStandardContains_shouldReturnFalse() {
+        String searchStr = "jAvA";
+        boolean result = LANGUAGES.contains(searchStr);
+        assertFalse(result);
+    }
+
+    @Test
+    void givenStringList_whenSearchIgnoreCaseUsingStreamAPI_shouldReturnTrue() {
+        String searchStr = "koTliN";
+        boolean result = LANGUAGES.stream().anyMatch(searchStr::equalsIgnoreCase);
+        assertTrue(result);
+    }
+
+    @Test
+    void givenStringList_whenUsingUtilClass_shouldReturnTrue() {
+        String searchStr = "ruBY";
+        boolean result = IgnoreCaseSearchUtil.ignoreCaseContains(LANGUAGES, searchStr);
+        assertTrue(result);
+    }
+
+    @Test
+    void givenStringList_whenUsingIgnoreCaseStringList_shouldReturnTrue() {
+        String searchStr = "pYtHoN";
+        List<String> ignoreCaseList = new IgnoreCaseStringList(LANGUAGES);
+        boolean result = ignoreCaseList.contains(searchStr);
+        assertTrue(result);
+
+        boolean resultContainAll = ignoreCaseList.containsAll(Arrays.asList("pYtHon", "jAvA", "koTliN", "ruBY"));
+        assertTrue(resultContainAll);
+    }
+}

core-java-modules/core-java-collections-array-list/src/test/java/com/baeldung/listofobjectstolistofstring/ConvertObjectListToStringListUnitTest.java

@@ -0,0 +1,92 @@
+package com.baeldung.listofobjectstolistofstring;
+
+import com.google.common.collect.Lists;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+public class ConvertObjectListToStringListUnitTest {
+
+    @Test
+    public void givenObjectList_whenForEachUsedToConvert_thenReturnSuccess() {
+        List<String> outputList = new ArrayList<>(objectListWithNull().size());
+        for (Object obj : objectListWithNull()) {
+            outputList.add(Objects.toString(obj, null));
+        }
+        Assert.assertEquals(expectedStringListWithNull(), outputList);
+    }
+
+    @Test
+    public void givenObjectList_whenUsingStreamsToConvert_thenReturnSuccess() {
+        List<String> outputList;
+        outputList = objectListWithNull().stream()
+          .map((obj) -> Objects.toString(obj, null))
+          .collect(Collectors.toList());
+        Assert.assertEquals(expectedStringListWithNull(), outputList);
+
+    }
+
+    @Test
+    public void givenObjectList_whenUsingStreamsUnmodifiableListToConvert_thenReturnSuccess() {
+        List<String> outputList;
+        outputList = objectListWithNull().stream()
+          .filter(Objects::nonNull)
+          .map((obj) -> Objects.toString(obj, null))
+          .collect(Collectors.toUnmodifiableList());
+        Assert.assertEquals(expectedStringListWithoutNull(), outputList);
+
+    }
+
+    @Test
+    public void givenObjectList_whenUsingGuavaTransform_thenReturnSuccess() {
+        List<String> outputList;
+        outputList = Lists.transform(objectListWithNull(), obj -> Objects.toString(obj, null));
+        Assert.assertEquals(expectedStringListWithNull(), outputList);
+    }
+
+    @Test
+    public void givenObjectListWithNoNull_whenUsingToList_thenReturnSuccess() {
+        List<String> outputList;
+        outputList = objectListWithoutNull().stream()
+          .map((obj) -> Objects.toString(obj, null))
+          .toList();
+        Assert.assertEquals(expectedStringListWithoutNull(), outputList);
+    }
+
+    private List<String> expectedStringListWithNull() {
+        List<String> listOfStrings = new ArrayList<>();
+        listOfStrings.add("1");
+        listOfStrings.add("true");
+        listOfStrings.add("hello");
+        listOfStrings.add(Double.toString(273773.98));
+        listOfStrings.add(null);
+        listOfStrings.add(new Node(2, 4).toString());
+        listOfStrings.add(new User("John Doe").toString());
+        return listOfStrings;
+    }
+
+    private List<Object> objectListWithNull() {
+        List<Object> listOfStrings = new ArrayList<>();
+        listOfStrings.add(1);
+        listOfStrings.add(true);
+        listOfStrings.add("hello");
+        listOfStrings.add(Double.valueOf(273773.98));
+        listOfStrings.add(null);
+        listOfStrings.add(new Node(2, 4));
+        listOfStrings.add(new User("John Doe"));
+        return listOfStrings;
+    }
+
+    private List<String> expectedStringListWithoutNull() {
+        return List.of("1", "true", "hello", Double.toString(273773.98), new Node(2, 4).toString(), new User("John Doe").toString());
+    }
+
+    private List<Object> objectListWithoutNull() {
+        return List.of(1, true, "hello", Double.valueOf(273773.98), new Node(2, 4), new User("John Doe"));
+    }
+}

core-java-modules/core-java-collections-array-list/src/test/java/com/baeldung/triple/TripleInListUnitTest.java

@@ -0,0 +1,105 @@
+package com.baeldung.triple;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+import org.junit.jupiter.api.Test;
+
+public class TripleInListUnitTest {
+
+    enum OP {
+        PLUS("+"), MINUS("-"), MULTIPLY("x");
+        final String opSign;
+
+        OP(String x) {
+            this.opSign = x;
+        }
+    }
+
+    private String createQuestion(Long num1, OP operator, Long num2) {
+        long result;
+        switch (operator) {
+            case PLUS:
+                result = num1 + num2;
+                break;
+            case MINUS:
+                result = num1 - num2;
+                break;
+            case MULTIPLY:
+                result = num1 * num2;
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown operator");
+        }
+        return String.format("%d %s %d = ? ( answer: %d )", num1, operator.opSign, num2, result);
+    }
+
+    private static final List<String> EXPECTED_QUESTIONS = Arrays.asList(
+        "100 - 42 = ? ( answer: 58 )",
+        "100 + 42 = ? ( answer: 142 )",
+        "100 x 42 = ? ( answer: 4200 )");
+
+    @Test
+    void givenTripleValues_whenStoreAsList_thenTypeIsNotSafe() {
+
+        List myTriple1 = new ArrayList(3);
+        myTriple1.add(100L);
+        myTriple1.add(OP.MINUS);
+        myTriple1.add(42L);
+
+        List myTriple2 = new ArrayList(3);
+        myTriple2.add(100L);
+        myTriple2.add(OP.PLUS);
+        myTriple2.add(42L);
+
+        List myTriple3 = new ArrayList(3);
+        myTriple3.add(100L);
+        myTriple3.add(OP.MULTIPLY);
+        myTriple3.add(42L);
+
+        List<List> listOfTriples = new ArrayList<>(Arrays.asList(myTriple1, myTriple2, myTriple3));
+
+        List oopsTriple = new ArrayList(3);
+        oopsTriple.add("Oops");
+        oopsTriple.add(911L);
+        oopsTriple.add("The type is wrong");
+
+        listOfTriples.add(oopsTriple);
+        assertEquals(4, listOfTriples.size());
+
+        List<String> questions = listOfTriples.stream()
+            .filter(
+                triple -> triple.size() == 3
+                    && triple.get(0) instanceof Long
+                    && triple.get(1) instanceof OP
+                    && triple.get(2) instanceof Long
+            ).map(triple -> {
+                Long left = (Long) triple.get(0);
+                OP op = (OP) triple.get(1);
+                Long right = (Long) triple.get(2);
+                return createQuestion(left, op, right);
+            }).collect(Collectors.toList());
+
+        assertEquals(EXPECTED_QUESTIONS, questions);
+    }
+
+    @Test
+    void givenTripleValues_whenUsingTheTripleClass_thenTypeIsSafeAndNeat() {
+        Triple<Long, OP, Long> triple1 = new Triple<>(100L, OP.MINUS, 42L);
+        Triple<Long, OP, Long> triple2 = new Triple<>(100L, OP.PLUS, 42L);
+        Triple<Long, OP, Long> triple3 = new Triple<>(100L, OP.MULTIPLY, 42L);
+        Triple<String, Long, String> tripleOops = new Triple<>("Oops", 911L, "The type is wrong");
+
+        List<Triple<Long, OP, Long>> listOfTriples = new ArrayList<>(Arrays.asList(triple1, triple2, triple3));
+        // listOfTriples.add(tripleOops); // Compiler error: "java: incompatible types ... "
+
+        List<String> questions = listOfTriples.stream()
+            .map(triple -> createQuestion(triple.getLeft(), triple.getMiddle(), triple.getRight()))
+            .collect(Collectors.toList());
+
+        assertEquals(EXPECTED_QUESTIONS, questions);
+    }
+}

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

@@ -5,4 +5,5 @@ This module contains articles about working with the Java Virtual Machine (JVM).
 ### Relevant Articles: 
 
 - [Difference Between Class.getResource() and ClassLoader.getResource()](https://www.baeldung.com/java-class-vs-classloader-getresource)
+- [Compiling and Executing Code From a String in Java](https://www.baeldung.com/java-string-compile-execute-code)
 - More articles: [[<-- prev]](/core-java-modules/core-java-jvm-2)

core-java-modules/core-java-jvm-3/src/main/java/com/baeldung/inmemorycompilation/InMemoryClass.java

@@ -0,0 +1,6 @@
+package com.baeldung.inmemorycompilation;
+
+public interface InMemoryClass {
+
+    void runCode();
+}

core-java-modules/core-java-jvm-3/src/main/java/com/baeldung/inmemorycompilation/InMemoryClassLoader.java

@@ -0,0 +1,30 @@
+package com.baeldung.inmemorycompilation;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.Map;
+
+public class InMemoryClassLoader extends ClassLoader {
+
+    private final InMemoryFileManager manager;
+
+    public InMemoryClassLoader(ClassLoader parent, InMemoryFileManager manager) {
+        super(parent);
+        this.manager = requireNonNull(manager, "manager must not be null");
+    }
+
+    @Override
+    protected Class<?> findClass(String name) throws ClassNotFoundException {
+
+        Map<String, JavaClassAsBytes> compiledClasses = manager
+            .getBytesMap();
+
+        if (compiledClasses.containsKey(name)) {
+            byte[] bytes = compiledClasses.get(name)
+                                          .getBytes();
+            return defineClass(name, bytes, 0, bytes.length);
+        } else {
+            throw new ClassNotFoundException();
+        }
+    }
+}

core-java-modules/core-java-jvm-3/src/main/java/com/baeldung/inmemorycompilation/InMemoryFileManager.java

@@ -0,0 +1,52 @@
+package com.baeldung.inmemorycompilation;
+
+import java.util.Hashtable;
+import java.util.Map;
+import javax.tools.FileObject;
+import javax.tools.ForwardingJavaFileManager;
+import javax.tools.JavaFileManager;
+import javax.tools.JavaFileObject;
+import javax.tools.JavaFileObject.Kind;
+import javax.tools.StandardJavaFileManager;
+
+public class InMemoryFileManager extends ForwardingJavaFileManager<JavaFileManager> {
+
+    private final Map<String, JavaClassAsBytes> compiledClasses;
+    private final ClassLoader loader;
+
+    public InMemoryFileManager(StandardJavaFileManager standardManager) {
+        super(standardManager);
+        this.compiledClasses = new Hashtable<>();
+        this.loader = new InMemoryClassLoader(this.getClass()
+                                                                                   .getClassLoader(),
+            this
+        );
+    }
+
+    /**
+     * Used to get the class loader for our compiled class. It creates an anonymous class extending
+     * the SecureClassLoader which uses the byte code created by the compiler and stored in the
+     * JavaClassObject, and returns the Class for it
+     *
+     * @param location where to place or search for file objects.
+     */
+    @Override
+    public ClassLoader getClassLoader(Location location) {
+        return loader;
+    }
+
+    @Override
+    public JavaFileObject getJavaFileForOutput(Location location, String className, Kind kind,
+        FileObject sibling) {
+
+        JavaClassAsBytes classAsBytes = new JavaClassAsBytes(
+            className, kind);
+        compiledClasses.put(className, classAsBytes);
+
+        return classAsBytes;
+    }
+
+    public Map<String, JavaClassAsBytes> getBytesMap() {
+        return compiledClasses;
+    }
+}

core-java-modules/core-java-jvm-3/src/main/java/com/baeldung/inmemorycompilation/JavaClassAsBytes.java

@@ -0,0 +1,27 @@
+package com.baeldung.inmemorycompilation;
+
+import java.io.ByteArrayOutputStream;
+import java.io.OutputStream;
+import java.net.URI;
+import javax.tools.SimpleJavaFileObject;
+
+/**
+ * Represents a Java class file (compiled byte-code)
+ */
+public class JavaClassAsBytes extends SimpleJavaFileObject {
+
+    protected final ByteArrayOutputStream bos = new ByteArrayOutputStream();
+
+    public JavaClassAsBytes(String name, Kind kind) {
+        super(URI.create("string:///" + name.replace('.', '/') + kind.extension), kind);
+    }
+
+    public byte[] getBytes() {
+        return bos.toByteArray();
+    }
+
+    @Override
+    public OutputStream openOutputStream() {
+        return bos;
+    }
+}

core-java-modules/core-java-jvm-3/src/main/java/com/baeldung/inmemorycompilation/JavaSourceFromString.java

@@ -0,0 +1,26 @@
+package com.baeldung.inmemorycompilation;
+
+import static java.util.Objects.requireNonNull;
+
+import java.net.URI;
+import javax.tools.SimpleJavaFileObject;
+
+/**
+ * Represents a Java source code file
+ */
+public class JavaSourceFromString extends SimpleJavaFileObject {
+
+    private final String sourceCode;
+
+    public JavaSourceFromString(String name, String sourceCode) {
+        super(URI.create("string:///" + name.replace('.', '/') + Kind.SOURCE.extension),
+            Kind.SOURCE
+        );
+        this.sourceCode = requireNonNull(sourceCode, "sourceCode must not be null");
+    }
+
+    @Override
+    public CharSequence getCharContent(boolean ignoreEncodingErrors) {
+        return sourceCode;
+    }
+}

core-java-modules/core-java-jvm-3/src/test/java/com/baeldung/inmemorycompilation/InMemoryCompilationUnitTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.inmemorycompilation;
+
+import java.util.Collections;
+import java.util.List;
+
+import javax.tools.DiagnosticCollector;
+import javax.tools.JavaCompiler;
+import javax.tools.JavaFileObject;
+import javax.tools.ToolProvider;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class InMemoryCompilationUnitTest {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(InMemoryCompilationUnitTest.class);
+
+    final static String QUALIFIED_CLASS_NAME = "com.baeldung.inmemorycompilation.TestClass";
+
+    final static String SOURCE_CODE =
+      "package com.baeldung.inmemorycompilation;\n"
+        + "public class TestClass implements InMemoryClass {\n"
+        + "@Override\n"
+        + "    public void runCode() {\n"
+        + "        System.out.println(\"code is running...\");\n"
+        + "    }\n"
+        + "}\n";
+
+    @Test
+    public void whenStringIsCompiled_ThenCodeShouldExecute() throws ClassNotFoundException, InstantiationException, IllegalAccessException {
+
+        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
+        DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<>();
+        InMemoryFileManager manager = new InMemoryFileManager(compiler.getStandardFileManager(null, null, null));
+
+        List<JavaFileObject> sourceFiles = Collections.singletonList(new JavaSourceFromString(QUALIFIED_CLASS_NAME, SOURCE_CODE));
+
+        JavaCompiler.CompilationTask task = compiler.getTask(null, manager, diagnostics, null, null, sourceFiles);
+
+        boolean result = task.call();
+
+        if (result) {
+            diagnostics.getDiagnostics()
+              .forEach(d -> LOGGER.error(String.valueOf(d)));
+        } else {
+            ClassLoader classLoader = manager.getClassLoader(null);
+            Class<?> clazz = classLoader.loadClass(QUALIFIED_CLASS_NAME);
+            InMemoryClass instanceOfClass = (InMemoryClass) clazz.newInstance();
+
+            Assertions.assertInstanceOf(InMemoryClass.class, instanceOfClass);
+
+            instanceOfClass.runCode();
+        }
+    }
+}

core-java-modules/core-java-jvm-3/src/test/java/com/baeldung/resource/ClassGetResourceUnitTest.java

@@ -1,10 +1,12 @@
 package com.baeldung.resource;
 
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import java.net.URL;
 
+@Disabled
 class ClassGetResourceUnitTest {
 
     @Test

core-java-modules/core-java-jvm-3/src/test/java/com/baeldung/resource/ClassLoaderGetResourceUnitTest.java

@@ -1,10 +1,12 @@
 package com.baeldung.resource;
 
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import java.net.URL;
 
+@Disabled
 class ClassLoaderGetResourceUnitTest {
 
     @Test

core-java-modules/core-java-lang-5/src/main/java/com/baeldung/convertnumberbases/ConvertNumberBases.java

@@ -5,65 +5,73 @@ public class ConvertNumberBases {
     public static String convertNumberToNewBase(String number, int base, int newBase) {
         return Integer.toString(Integer.parseInt(number, base), newBase);
     }
+
     public static String convertNumberToNewBaseCustom(String num, int base, int newBase) {
         int decimalNumber = convertFromAnyBaseToDecimal(num, base);
-        return convertFromDecimalToBaseX(decimalNumber, newBase);
+        String targetBase = "";
+        try {
+            targetBase = convertFromDecimalToBaseX(decimalNumber, newBase);
+        } catch (IllegalArgumentException e) {
+            e.printStackTrace();
+        }
+        return  targetBase;
     }
 
-    public static String convertFromDecimalToBaseX(int num, int newBase) {
+    public static String convertFromDecimalToBaseX(int num, int newBase) throws IllegalArgumentException {
+        if ((newBase < 2 || newBase > 10) && newBase != 16) {
+            throw new IllegalArgumentException("New base must be from 2 - 10 or 16");
+        }
 
         String result = "";
         int remainder;
         while (num > 0) {
             remainder = num % newBase;
             if (newBase == 16) {
-                if (remainder == 10)
+                if (remainder == 10) {
                     result += 'A';
-                else if (remainder == 11)
+                } else if (remainder == 11) {
                     result += 'B';
-                else if (remainder == 12)
+                } else if (remainder == 12) {
                     result += 'C';
-                else if (remainder == 13)
+                } else if (remainder == 13) {
                     result += 'D';
-                else if (remainder == 14)
+                } else if (remainder == 14) {
                     result += 'E';
-                else if (remainder == 15)
+                } else if (remainder == 15) {
                     result += 'F';
-                else
+                } else {
                     result += remainder;
-            } else
+                }
+            } else {
                 result += remainder;
-
+            }
             num /= newBase;
         }
         return new StringBuffer(result).reverse().toString();
     }
 
     public static int convertFromAnyBaseToDecimal(String num, int base) {
-
+        if (base < 2 || (base > 10 && base != 16)) {
-        if (base < 2 || (base > 10 && base != 16))
             return -1;
-
+        }
         int val = 0;
         int power = 1;
-
         for (int i = num.length() - 1; i >= 0; i--) {
             int digit = charToDecimal(num.charAt(i));
-
+            if (digit < 0 || digit >= base) {
-            if (digit < 0 || digit >= base)
                 return -1;
-
+            }
             val += digit * power;
             power = power * base;
         }
-
         return val;
     }
 
     public static int charToDecimal(char c) {
-        if (c >= '0' && c <= '9')
+        if (c >= '0' && c <= '9') {
             return (int) c - '0';
-        else
+        } else {
             return (int) c - 'A' + 10;
         }
     }
+}

core-java-modules/core-java-lang-5/src/test/java/com/baeldung/convertnumberbases/ConvertNumberBasesUnitTest.java

@@ -1,5 +1,6 @@
 package com.baeldung.convertnumberbases;
 
+import static com.baeldung.convertnumberbases.ConvertNumberBases.convertFromDecimalToBaseX;
 import static com.baeldung.convertnumberbases.ConvertNumberBases.convertNumberToNewBase;
 import static com.baeldung.convertnumberbases.ConvertNumberBases.convertNumberToNewBaseCustom;
 import static org.junit.jupiter.api.Assertions.*;
@@ -17,4 +18,15 @@ class ConvertNumberBasesUnitTest {
         assertEquals(convertNumberToNewBaseCustom("11001000", 2, 8), "310");
     }
 
+    @Test
+    void whenInputIsOutOfRange_thenIllegalArgumentExceptionIsThrown() {
+        Exception exception = assertThrows(IllegalArgumentException.class, ()-> {
+            convertFromDecimalToBaseX(100, 12);
+        });
+        String expectedMessage = "New base must be from 2 - 10 or 16";
+        String actualMessage = exception.getMessage();
+
+        assertTrue(actualMessage.contains(expectedMessage));
+    }
+
 }

core-java-modules/core-java-lang-oop-others/README.md

@@ -6,3 +6,4 @@ This module contains articles about Object Oriented Programming (OOP) in Java
 - [Object-Oriented-Programming Concepts in Java](https://www.baeldung.com/java-oop)
 - [Static and Dynamic Binding in Java](https://www.baeldung.com/java-static-dynamic-binding)
 - [Pass-By-Value as a Parameter Passing Mechanism in Java](https://www.baeldung.com/java-pass-by-value-or-pass-by-reference)
+- [Check If All the Variables of an Object Are Null](https://www.baeldung.com/java-check-all-variables-object-null)

core-java-modules/core-java-streams-4/README.md

@@ -5,3 +5,4 @@
 - [Filter Java Stream to 1 and Only 1 Element](https://www.baeldung.com/java-filter-stream-unique-element)
 - [Java 8 Streams: Multiple Filters vs. Complex Condition](https://www.baeldung.com/java-streams-multiple-filters-vs-condition)
 - [Finding Max Date in List Using Streams](https://www.baeldung.com/java-max-date-list-streams)
+- [Batch Processing of Stream Data in Java](https://www.baeldung.com/java-stream-batch-processing)

core-java-modules/core-java-streams-4/pom.xml

@@ -59,6 +59,36 @@
             <version>3.12.0</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>io.reactivex.rxjava3</groupId>
+            <artifactId>rxjava</artifactId>
+            <version>${rx.java3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.vavr</groupId>
+            <artifactId>vavr</artifactId>
+            <version>${io.varv.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.projectreactor</groupId>
+            <artifactId>reactor-core</artifactId>
+            <version>${io.reactor3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${apache.commons.collection4.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${google.guava.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.oath.cyclops</groupId>
+            <artifactId>cyclops</artifactId>
+            <version>${cyclops.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -90,6 +120,12 @@
         <maven.compiler.target>12</maven.compiler.target>
         <rx.java.version>1.2.5</rx.java.version>
         <rx.java2.version>2.2.2</rx.java2.version>
+        <rx.java3.version>3.1.5</rx.java3.version>
+        <io.varv.version>1.0.0-alpha-4</io.varv.version>
+        <io.reactor3.version>3.5.1</io.reactor3.version>
+        <apache.commons.collection4.version>4.4</apache.commons.collection4.version>
+        <google.guava.version>31.1-jre</google.guava.version>
+        <cyclops.version>10.4.1</cyclops.version>
     </properties>
 
 </project>

core-java-modules/core-java-streams-4/src/main/java/com/baeldung/streams/processing/CustomBatchIterator.java

@@ -0,0 +1,47 @@
+package com.baeldung.streams.processing;
+
+import static java.util.Spliterator.ORDERED;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Spliterators;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+public class CustomBatchIterator<T> implements Iterator<List<T>> {
+    private final int batchSize;
+    private List<T> currentBatch;
+    private final Iterator<T> iterator;
+
+    public CustomBatchIterator(Iterator<T> sourceIterator, int batchSize) {
+        this.batchSize = batchSize;
+        this.iterator = sourceIterator;
+    }
+
+    @Override
+    public List<T> next() {
+        return currentBatch;
+    }
+
+    @Override
+    public boolean hasNext() {
+        prepareNextBatch();
+        return currentBatch != null && !currentBatch.isEmpty();
+    }
+
+    public static <T> Stream<List<T>> batchStreamOf(Stream<T> stream, int batchSize) {
+        return stream(new CustomBatchIterator<>(stream.iterator(), batchSize));
+    }
+
+    private static <T> Stream<T> stream(Iterator<T> iterator) {
+        return StreamSupport.stream(Spliterators.spliteratorUnknownSize(iterator, ORDERED), false);
+    }
+
+    private void prepareNextBatch() {
+        currentBatch = new ArrayList<>(batchSize);
+        while (iterator.hasNext() && currentBatch.size() < batchSize) {
+            currentBatch.add(iterator.next());
+        }
+    }
+}

core-java-modules/core-java-streams-4/src/test/java/com/baeldung/streams/processing/StreamProcessingUnitTest.java

@@ -0,0 +1,141 @@
+package com.baeldung.streams.processing;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+import org.apache.commons.collections4.ListUtils;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import com.google.common.collect.Iterators;
+
+import cyclops.data.LazySeq;
+import cyclops.reactive.ReactiveSeq;
+import io.reactivex.rxjava3.core.Observable;
+import reactor.core.publisher.Flux;
+
+public class StreamProcessingUnitTest {
+    public final int BATCH_SIZE = 10;
+
+    private final List<Integer> firstBatch = List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
+    private final List<Integer> secondBatch = List.of(10, 11, 12, 13, 14, 15, 16, 17, 18, 19);
+    private final List<Integer> thirdBatch = List.of(20, 21, 22, 23, 24, 25, 26, 27, 28, 29);
+    private final List<Integer> fourthBatch = List.of(30, 31, 32, 33);
+
+    public Stream<Integer> data;
+
+    @BeforeEach
+    public void setUp() {
+        data = IntStream.range(0, 34)
+          .boxed();
+    }
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchUsingSpliterator_thenFourBatchesAreObtained() {
+        Collection<List<Integer>> result = new ArrayList<>();
+        CustomBatchIterator.batchStreamOf(data, BATCH_SIZE)
+          .forEach(result::add);
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchUsingCollectionAPI_thenFourBatchesAreObtained() {
+        Collection<List<Integer>> result = data.collect(Collectors.groupingBy(it -> it / BATCH_SIZE))
+          .values();
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchParallelUsingCollectionAPI_thenFourBatchesAreObtained() {
+        Collection<List<Integer>> result = data.parallel()
+          .collect(Collectors.groupingBy(it -> it / BATCH_SIZE))
+          .values();
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchUsingRxJavaV3_thenFourBatchesAreObtained() {
+        // RxJava v3
+        Collection<List<Integer>> result = new ArrayList<>();
+        Observable.fromStream(data)
+          .buffer(BATCH_SIZE)
+          .subscribe(result::add);
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchUsingReactor_thenFourBatchesAreObtained() {
+        Collection<List<Integer>> result = new ArrayList<>();
+        Flux.fromStream(data)
+          .buffer(BATCH_SIZE)
+          .subscribe(result::add);
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchUsingApacheCommon_thenFourBatchesAreObtained() {
+        Collection<List<Integer>> result = new ArrayList<>(ListUtils.partition(data.collect(Collectors.toList()), BATCH_SIZE));
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchUsingGuava_thenFourBatchesAreObtained() {
+        Collection<List<Integer>> result = new ArrayList<>();
+        Iterators.partition(data.iterator(), BATCH_SIZE)
+          .forEachRemaining(result::add);
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchUsingCyclops_thenFourBatchesAreObtained() {
+        Collection<List<Integer>> result = new ArrayList<>();
+        ReactiveSeq.fromStream(data)
+          .grouped(BATCH_SIZE)
+          .toList()
+          .forEach(value -> result.add(value.collect(Collectors.toList())));
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchUsingCyclopsLazy_thenFourBatchesAreObtained() {
+        Collection<List<Integer>> result = new ArrayList<>();
+        LazySeq.fromStream(data)
+          .grouped(BATCH_SIZE)
+          .toList()
+          .forEach(value -> result.add(value.collect(Collectors.toList())));
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+}

core-java-modules/core-java-streams-4/src/test/java/com/baeldung/streams/processing/vavr/StreamProcessingWithVavrUnitTest.java

@@ -0,0 +1,30 @@
+package com.baeldung.streams.processing.vavr;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.streams.processing.StreamProcessingUnitTest;
+
+import io.vavr.collection.List;
+import io.vavr.collection.Stream;
+
+public class StreamProcessingWithVavrUnitTest extends StreamProcessingUnitTest {
+
+    private final List<Integer> firstBatch = List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
+    private final List<Integer> secondBatch = List.of(10, 11, 12, 13, 14, 15, 16, 17, 18, 19);
+    private final List<Integer> thirdBatch = List.of(20, 21, 22, 23, 24, 25, 26, 27, 28, 29);
+    private final List<Integer> fourthBatch = List.of(30, 31, 32, 33);
+
+    @Test
+    public void givenAStreamOfData_whenIsProcessingInBatchUsingVavr_thenFourBatchesAreObtained() {
+        List<List<Integer>> result = Stream.ofAll(data)
+          .toList()
+          .grouped(BATCH_SIZE)
+          .toList();
+        assertTrue(result.contains(firstBatch));
+        assertTrue(result.contains(secondBatch));
+        assertTrue(result.contains(thirdBatch));
+        assertTrue(result.contains(fourthBatch));
+    }
+}

core-java-modules/core-java-uuid/src/main/java/com/baeldung/uuid/UUIDGenerator.java

@@ -27,17 +27,17 @@ public final class UUIDGenerator {
 
     private static long get64LeastSignificantBitsForVersion1() {
         final long random63BitLong = new Random().nextLong() & 0x3FFFFFFFFFFFFFFFL;
-        final long variant3BitFlag = 0x8000000000000000L;
+        long variant3BitFlag = 0x8000000000000000L;
-        return random63BitLong + variant3BitFlag;
+        return random63BitLong | variant3BitFlag;
     }
 
     private static long get64MostSignificantBitsForVersion1() {
-        final long timeForUuidIn100Nanos = System.currentTimeMillis();
+        final long currentTimeMillis = System.currentTimeMillis();
-        final long time_low = (timeForUuidIn100Nanos & 0x0000_0000_FFFF_FFFFL) << 32;
+        final long time_low = (currentTimeMillis & 0x0000_0000_FFFF_FFFFL) << 32;
-        final long time_mid = ((timeForUuidIn100Nanos >> 32) & 0xFFFF) << 16;
+        final long time_mid = ((currentTimeMillis >> 32) & 0xFFFF) << 16;
         final long version = 1 << 12;
-        final long time_hi = ((timeForUuidIn100Nanos >> 48) & 0x0FFF);
+        final long time_high = ((currentTimeMillis >> 48) & 0x0FFF);
-        return time_low + time_mid + version + time_hi;
+        return time_low | time_mid | version | time_high;
     }
 
     /**

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

@@ -9,3 +9,4 @@
 - [A Guide to the ResourceBundle](http://www.baeldung.com/java-resourcebundle)
 - [Merging java.util.Properties Objects](https://www.baeldung.com/java-merging-properties)
 - [Illegal Character Compilation Error](https://www.baeldung.com/java-illegal-character-error)
+- [Lambda Expression vs. Anonymous Inner Class](https://www.baeldung.com/java-lambdas-vs-anonymous-class)

core-java-modules/pom.xml

@@ -31,7 +31,6 @@
         <module>core-java-collections-2</module>
         <module>core-java-collections-3</module>
         <module>core-java-collections-4</module>
-        <module>core-java-collections-array-list</module>
         <module>core-java-collections-conversions</module>
         <module>core-java-collections-conversions-2</module>
         <module>core-java-collections-set-2</module>

httpclient-simple/pom.xml

@@ -112,6 +112,18 @@
                 </exclusion>
             </exclusions>
         </dependency>
+
+        <dependency>
+            <groupId>org.apache.httpcomponents.client5</groupId>
+            <artifactId>httpclient5-fluent</artifactId>
+            <version>${httpclient5-fluent.version}</version>
+            <exclusions>
+                <exclusion>
+                    <artifactId>commons-logging</artifactId>
+                    <groupId>commons-logging</groupId>
+                </exclusion>
+            </exclusions>
+        </dependency>
         <!-- utils -->
         <dependency>
             <groupId>org.apache.commons</groupId>
@@ -308,6 +320,7 @@
         <!-- http client & core 5 -->
         <httpcore5.version>5.2</httpcore5.version>
         <httpclient5.version>5.2</httpclient5.version>
+        <httpclient5-fluent.version>5.2</httpclient5-fluent.version>
         <!-- maven plugins -->
         <cargo-maven2-plugin.version>1.6.1</cargo-maven2-plugin.version>
     </properties>

httpclient-simple/src/test/java/com/baeldung/httpclient/HttpClientPostingLiveTest.java

@@ -1,74 +1,88 @@
 package com.baeldung.httpclient;
 
-import org.apache.http.HttpEntity;
+import static org.hamcrest.MatcherAssert.assertThat;
-import org.apache.http.HttpResponse;
+import static org.hamcrest.Matchers.equalTo;
-import org.apache.http.NameValuePair;
+import static org.junit.jupiter.api.Assertions.assertFalse;
-import org.apache.http.auth.AuthenticationException;
+
-import org.apache.http.auth.UsernamePasswordCredentials;
+import org.junit.jupiter.api.Test;
-import org.apache.http.client.entity.UrlEncodedFormEntity;
+
-import org.apache.http.client.fluent.Form;
+import org.apache.hc.client5.http.auth.AuthScope;
-import org.apache.http.client.fluent.Request;
+import org.apache.hc.client5.http.auth.UsernamePasswordCredentials;
-import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.hc.client5.http.classic.methods.HttpPost;
-import org.apache.http.client.methods.HttpPost;
+import org.apache.hc.client5.http.entity.UrlEncodedFormEntity;
-import org.apache.http.entity.ContentType;
+import org.apache.hc.client5.http.entity.mime.MultipartEntityBuilder;
-import org.apache.http.entity.StringEntity;
+import org.apache.hc.client5.http.fluent.Form;
-import org.apache.http.entity.mime.MultipartEntityBuilder;
+import org.apache.hc.client5.http.impl.auth.BasicCredentialsProvider;
-import org.apache.http.impl.auth.BasicScheme;
+import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
-import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
-import org.apache.http.impl.client.HttpClients;
+import org.apache.hc.client5.http.impl.classic.HttpClients;
-import org.apache.http.message.BasicNameValuePair;
+import org.apache.hc.core5.http.ContentType;
-import org.junit.Test;
+import org.apache.hc.core5.http.HttpEntity;
+import org.apache.hc.core5.http.HttpResponse;
+import org.apache.hc.core5.http.HttpStatus;
+import org.apache.hc.core5.http.NameValuePair;
+import org.apache.hc.client5.http.fluent.Request;
+import org.apache.hc.core5.http.io.entity.StringEntity;
+import org.apache.hc.core5.http.message.BasicNameValuePair;
 
 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
-import static org.hamcrest.Matchers.equalTo;
+import com.baeldung.handler.CustomHttpClientResponseHandler;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertThat;
 
 /*
  * NOTE : Need module spring-rest to be running
  */
-public class HttpClientPostingLiveTest {
+class HttpClientPostingLiveTest {
     private static final String SAMPLE_URL = "http://www.example.com";
     private static final String URL_SECURED_BY_BASIC_AUTHENTICATION = "http://browserspy.dk/password-ok.php";
     private static final String DEFAULT_USER = "test";
     private static final String DEFAULT_PASS = "test";
 
     @Test
-    public void whenSendPostRequestUsingHttpClient_thenCorrect() throws IOException {
+    void whenSendPostRequestUsingHttpClient_thenCorrect() throws IOException {
-        final CloseableHttpClient client = HttpClients.createDefault();
         final HttpPost httpPost = new HttpPost(SAMPLE_URL);
-
         final List<NameValuePair> params = new ArrayList<NameValuePair>();
         params.add(new BasicNameValuePair("username", DEFAULT_USER));
         params.add(new BasicNameValuePair("password", DEFAULT_PASS));
         httpPost.setEntity(new UrlEncodedFormEntity(params));
 
-        final CloseableHttpResponse response = client.execute(httpPost);
+        try (CloseableHttpClient client = HttpClients.createDefault();
-        assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
+            CloseableHttpResponse response = (CloseableHttpResponse) client
-        client.close();
+                .execute(httpPost, new CustomHttpClientResponseHandler())) {
+
+            final int statusCode = response.getCode();
+            assertThat(statusCode, equalTo(HttpStatus.SC_OK));
+        }
     }
 
     @Test
-    public void whenSendPostRequestWithAuthorizationUsingHttpClient_thenCorrect() throws IOException, AuthenticationException {
+    void whenSendPostRequestWithAuthorizationUsingHttpClient_thenCorrect() throws IOException {
-        final CloseableHttpClient client = HttpClients.createDefault();
         final HttpPost httpPost = new HttpPost(URL_SECURED_BY_BASIC_AUTHENTICATION);
-
         httpPost.setEntity(new StringEntity("test post"));
-        final UsernamePasswordCredentials creds = new UsernamePasswordCredentials(DEFAULT_USER, DEFAULT_PASS);
-        httpPost.addHeader(new BasicScheme().authenticate(creds, httpPost, null));
 
-        final CloseableHttpResponse response = client.execute(httpPost);
+        final BasicCredentialsProvider credsProvider = new BasicCredentialsProvider();
-        assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
+        final UsernamePasswordCredentials credentials =
-        client.close();
+            new UsernamePasswordCredentials(DEFAULT_USER, DEFAULT_PASS.toCharArray());
+
+        credsProvider.setCredentials(new AuthScope(URL_SECURED_BY_BASIC_AUTHENTICATION, 80) ,credentials);
+
+        try (CloseableHttpClient client = HttpClients.custom()
+            .setDefaultCredentialsProvider(credsProvider)
+            .build();
+
+            CloseableHttpResponse response = (CloseableHttpResponse) client
+                .execute(httpPost, new CustomHttpClientResponseHandler())) {
+
+            final int statusCode = response.getCode();
+            assertThat(statusCode, equalTo(HttpStatus.SC_OK));
+        }
     }
 
     @Test
-    public void whenPostJsonUsingHttpClient_thenCorrect() throws IOException {
+    void whenPostJsonUsingHttpClient_thenCorrect() throws IOException {
-        final CloseableHttpClient client = HttpClients.createDefault();
         final HttpPost httpPost = new HttpPost(SAMPLE_URL);
 
         final String json = "{\"id\":1,\"name\":\"John\"}";
@@ -77,68 +91,91 @@ public class HttpClientPostingLiveTest {
         httpPost.setHeader("Accept", "application/json");
         httpPost.setHeader("Content-type", "application/json");
 
-        final CloseableHttpResponse response = client.execute(httpPost);
+        try (CloseableHttpClient client = HttpClients.createDefault();
-        assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
+            CloseableHttpResponse response = (CloseableHttpResponse) client
-        client.close();
+                .execute(httpPost, new CustomHttpClientResponseHandler())) {
+
+            final int statusCode = response.getCode();
+            assertThat(statusCode, equalTo(HttpStatus.SC_OK));
+        }
     }
 
     @Test
-    public void whenPostFormUsingHttpClientFluentAPI_thenCorrect() throws IOException {
+    void whenPostFormUsingHttpClientFluentAPI_thenCorrect() throws IOException {
-        final HttpResponse response = Request.Post(SAMPLE_URL).bodyForm(Form.form().add("username", DEFAULT_USER).add("password", DEFAULT_PASS).build()).execute().returnResponse();
+        Request request = Request.post(SAMPLE_URL)
+            .bodyForm(Form.form()
+                .add("username", DEFAULT_USER)
+                .add("password", DEFAULT_PASS)
+                .build());
 
-        assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
+        HttpResponse response = request.execute()
+            .returnResponse();
+        assertThat(response.getCode(), equalTo(HttpStatus.SC_OK));
     }
 
     @Test
-    public void whenSendMultipartRequestUsingHttpClient_thenCorrect() throws IOException {
+    void whenSendMultipartRequestUsingHttpClient_thenCorrect() throws IOException {
-        final CloseableHttpClient client = HttpClients.createDefault();
         final HttpPost httpPost = new HttpPost(SAMPLE_URL);
 
         final MultipartEntityBuilder builder = MultipartEntityBuilder.create();
         builder.addTextBody("username", DEFAULT_USER);
         builder.addTextBody("password", DEFAULT_PASS);
-        builder.addBinaryBody("file", new File("src/test/resources/test.in"), ContentType.APPLICATION_OCTET_STREAM, "file.ext");
+        builder.addBinaryBody(
+            "file", new File("src/test/resources/test.in"), ContentType.APPLICATION_OCTET_STREAM, "file.ext");
+
+        final HttpEntity multipart = builder.build();
+        httpPost.setEntity(multipart);
+
+        try (CloseableHttpClient client = HttpClients.createDefault();
+            CloseableHttpResponse response = (CloseableHttpResponse) client
+                .execute(httpPost, new CustomHttpClientResponseHandler())) {
+
+            final int statusCode = response.getCode();
+            assertThat(statusCode, equalTo(HttpStatus.SC_OK));
+        }
+    }
+
+    @Test
+    void whenUploadFileUsingHttpClient_thenCorrect() throws IOException {
+        final HttpPost httpPost = new HttpPost(SAMPLE_URL);
+
+        final MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+        builder.addBinaryBody(
+            "file", new File("src/test/resources/test.in"), ContentType.APPLICATION_OCTET_STREAM, "file.ext");
         final HttpEntity multipart = builder.build();
 
         httpPost.setEntity(multipart);
 
-        final CloseableHttpResponse response = client.execute(httpPost);
+        try (CloseableHttpClient client = HttpClients.createDefault();
-        assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
+            CloseableHttpResponse response = (CloseableHttpResponse) client
-        client.close();
+                .execute(httpPost, new CustomHttpClientResponseHandler())) {
+
+            final int statusCode = response.getCode();
+            assertThat(statusCode, equalTo(HttpStatus.SC_OK));
+        }
     }
 
     @Test
-    public void whenUploadFileUsingHttpClient_thenCorrect() throws IOException {
+    void whenGetUploadFileProgressUsingHttpClient_thenCorrect() throws IOException {
-        final CloseableHttpClient client = HttpClients.createDefault();
         final HttpPost httpPost = new HttpPost(SAMPLE_URL);
 
         final MultipartEntityBuilder builder = MultipartEntityBuilder.create();
-        builder.addBinaryBody("file", new File("src/test/resources/test.in"), ContentType.APPLICATION_OCTET_STREAM, "file.ext");
+        builder.addBinaryBody(
+            "file", new File("src/test/resources/test.in"), ContentType.APPLICATION_OCTET_STREAM, "file.ext");
         final HttpEntity multipart = builder.build();
 
-        httpPost.setEntity(multipart);
+        final ProgressEntityWrapper.ProgressListener pListener =
-
+            percentage -> assertFalse(Float.compare(percentage, 100) > 0);
-        final CloseableHttpResponse response = client.execute(httpPost);
-        assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
-        client.close();
-    }
-
-    @Test
-    public void whenGetUploadFileProgressUsingHttpClient_thenCorrect() throws IOException {
-        final CloseableHttpClient client = HttpClients.createDefault();
-        final HttpPost httpPost = new HttpPost(SAMPLE_URL);
-
-        final MultipartEntityBuilder builder = MultipartEntityBuilder.create();
-        builder.addBinaryBody("file", new File("src/test/resources/test.in"), ContentType.APPLICATION_OCTET_STREAM, "file.ext");
-        final HttpEntity multipart = builder.build();
-
-        final ProgressEntityWrapper.ProgressListener pListener = percentage -> assertFalse(Float.compare(percentage, 100) > 0);
 
         httpPost.setEntity(new ProgressEntityWrapper(multipart, pListener));
 
-        final CloseableHttpResponse response = client.execute(httpPost);
+        try (CloseableHttpClient client = HttpClients.createDefault();
-        assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
+            CloseableHttpResponse response = (CloseableHttpResponse) client
-        client.close();
+                .execute(httpPost, new CustomHttpClientResponseHandler())) {
+
+            final int statusCode = response.getCode();
+            assertThat(statusCode, equalTo(HttpStatus.SC_OK));
+        }
     }
 
 }

httpclient-simple/src/test/java/com/baeldung/httpclient/ProgressEntityWrapper.java

@@ -4,8 +4,8 @@ import java.io.FilterOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 
-import org.apache.http.HttpEntity;
+import org.apache.hc.core5.http.HttpEntity;
-import org.apache.http.entity.HttpEntityWrapper;
+import org.apache.hc.core5.http.io.entity.HttpEntityWrapper;
 
 public class ProgressEntityWrapper extends HttpEntityWrapper {
     private final ProgressListener listener;

httpclient-simple/src/test/java/com/baeldung/httpclient/sec/HttpClientAuthLiveTest.java

@@ -1,118 +1,119 @@
 package com.baeldung.httpclient.sec;
 
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+
 import org.apache.commons.codec.binary.Base64;
-import org.apache.http.HttpHeaders;
+
-import org.apache.http.HttpHost;
+import com.baeldung.handler.CustomHttpClientResponseHandler;
-import org.apache.http.HttpStatus;
+
-import org.apache.http.auth.AuthScope;
+import org.apache.hc.client5.http.auth.AuthScope;
-import org.apache.http.auth.UsernamePasswordCredentials;
+import org.apache.hc.client5.http.auth.AuthCache;
-import org.apache.http.client.AuthCache;
+import org.apache.hc.client5.http.auth.CredentialsProvider;
-import org.apache.http.client.CredentialsProvider;
+import org.apache.hc.client5.http.auth.UsernamePasswordCredentials;
-import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.hc.client5.http.classic.methods.HttpGet;
-import org.apache.http.client.methods.HttpGet;
+import org.apache.hc.client5.http.impl.auth.BasicAuthCache;
-import org.apache.http.client.protocol.HttpClientContext;
+import org.apache.hc.client5.http.impl.auth.BasicCredentialsProvider;
-import org.apache.http.impl.auth.BasicScheme;
+import org.apache.hc.client5.http.impl.auth.BasicScheme;
-import org.apache.http.impl.client.BasicAuthCache;
+import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
-import org.apache.http.impl.client.BasicCredentialsProvider;
+import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
-import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.hc.client5.http.impl.classic.HttpClientBuilder;
-import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.hc.client5.http.protocol.HttpClientContext;
-import org.apache.http.protocol.HttpContext;
+import org.apache.hc.core5.http.HttpHeaders;
-import com.baeldung.httpclient.ResponseUtil;
+import org.apache.hc.core5.http.HttpHost;
-import org.junit.After;
+import org.apache.hc.core5.http.HttpStatus;
-import org.junit.Before;
+import org.apache.hc.core5.http.protocol.HttpContext;
-import org.junit.Test;
+
+import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 
-import static org.hamcrest.Matchers.equalTo;
-import static org.junit.Assert.assertThat;
-
 /*
  * NOTE : Need module httpclient-simple to be running
  */
-
+class HttpClientAuthLiveTest {
-public class HttpClientAuthLiveTest {
 
     private static final String URL_SECURED_BY_BASIC_AUTHENTICATION = "http://localhost:8082/httpclient-simple/api/foos/1";
     private static final String DEFAULT_USER = "user1";
     private static final String DEFAULT_PASS = "user1Pass";
-
+    private final char[] DEFAULT_PASS_ARRAY = DEFAULT_PASS.toCharArray() ;
-    private CloseableHttpClient client;
-
-    private CloseableHttpResponse response;
-
-    @Before
-    public final void before() {
-        client = HttpClientBuilder.create().build();
-    }
-
-    @After
-    public final void after() throws IllegalStateException, IOException {
-        ResponseUtil.closeResponse(response);
-    }
-
-    // tests
 
     @Test
-    public final void whenExecutingBasicGetRequestWithBasicAuthenticationEnabled_thenSuccess() throws IOException {
+    final void whenExecutingBasicGetRequestWithBasicAuthenticationEnabled_thenSuccess() throws IOException {
-        client = HttpClientBuilder.create().setDefaultCredentialsProvider(provider()).build();
+        final HttpGet request = new HttpGet(URL_SECURED_BY_BASIC_AUTHENTICATION);
+        try (CloseableHttpClient client = HttpClientBuilder.create()
+            .setDefaultCredentialsProvider(provider())
+            .build();
 
-        response = client.execute(new HttpGet(URL_SECURED_BY_BASIC_AUTHENTICATION));
+            CloseableHttpResponse response = (CloseableHttpResponse) client
-
+                .execute(request, new CustomHttpClientResponseHandler())) {
-        final int statusCode = response.getStatusLine().getStatusCode();
+            final int statusCode = response.getCode();
             assertThat(statusCode, equalTo(HttpStatus.SC_OK));
         }
-
-    @Test
-    public final void givenAuthenticationIsPreemptive_whenExecutingBasicGetRequestWithBasicAuthenticationEnabled_thenSuccess() throws IOException {
-        client = HttpClientBuilder.create().build();
-        response = client.execute(new HttpGet(URL_SECURED_BY_BASIC_AUTHENTICATION), context());
-
-        final int statusCode = response.getStatusLine().getStatusCode();
-        assertThat(statusCode, equalTo(HttpStatus.SC_OK));
     }
 
     @Test
-    public final void givenAuthorizationHeaderIsSetManually_whenExecutingGetRequest_thenSuccess() throws IOException {
+    final void givenAuthenticationIsPreemptive_whenExecutingBasicGetRequestWithBasicAuthenticationEnabled_thenSuccess() throws IOException {
-        client = HttpClientBuilder.create().build();
+        final HttpGet request = new HttpGet(URL_SECURED_BY_BASIC_AUTHENTICATION);
+        try (CloseableHttpClient client = HttpClientBuilder.create()
+            .build();
 
+            CloseableHttpResponse response = (CloseableHttpResponse) client
+                .execute(request, context(), new CustomHttpClientResponseHandler())) {
+            final int statusCode = response.getCode();
+            assertThat(statusCode, equalTo(200));
+        }
+    }
+
+    @Test
+    final void givenAuthorizationHeaderIsSetManually_whenExecutingGetRequest_thenSuccess() throws IOException {
         final HttpGet request = new HttpGet(URL_SECURED_BY_BASIC_AUTHENTICATION);
         request.setHeader(HttpHeaders.AUTHORIZATION, authorizationHeader(DEFAULT_USER, DEFAULT_PASS));
-        response = client.execute(request);
+        try (CloseableHttpClient client = HttpClientBuilder.create()
+            .build();
 
-        final int statusCode = response.getStatusLine().getStatusCode();
+            CloseableHttpResponse response = (CloseableHttpResponse) client
+                .execute(request, context(), new CustomHttpClientResponseHandler())) {
+            final int statusCode = response.getCode();
             assertThat(statusCode, equalTo(HttpStatus.SC_OK));
         }
+    }
 
     @Test
-    public final void givenAuthorizationHeaderIsSetManually_whenExecutingGetRequest_thenSuccess2() throws IOException {
+    final void givenAuthorizationHeaderIsSetManually_whenExecutingGetRequest_thenSuccess2() throws IOException {
         final HttpGet request = new HttpGet(URL_SECURED_BY_BASIC_AUTHENTICATION);
         final String auth = DEFAULT_USER + ":" + DEFAULT_PASS;
         final byte[] encodedAuth = Base64.encodeBase64(auth.getBytes(StandardCharsets.ISO_8859_1));
         final String authHeader = "Basic " + new String(encodedAuth);
         request.setHeader(HttpHeaders.AUTHORIZATION, authHeader);
 
-        client = HttpClientBuilder.create().build();
+        try (CloseableHttpClient client = HttpClientBuilder.create()
-        response = client.execute(request);
+            .build();
 
-        final int statusCode = response.getStatusLine().getStatusCode();
+            CloseableHttpResponse response = (CloseableHttpResponse) client
+                .execute(request, new CustomHttpClientResponseHandler())) {
+            final int statusCode = response.getCode();
             assertThat(statusCode, equalTo(HttpStatus.SC_OK));
         }
+    }
 
     // UTILS
 
     private CredentialsProvider provider() {
-        final CredentialsProvider provider = new BasicCredentialsProvider();
+        final HttpHost targetHost = new HttpHost("http", "localhost", 8082);
-        final UsernamePasswordCredentials credentials = new UsernamePasswordCredentials(DEFAULT_USER, DEFAULT_PASS);
+        final BasicCredentialsProvider provider = new BasicCredentialsProvider();
-        provider.setCredentials(AuthScope.ANY, credentials);
+        AuthScope authScope = new AuthScope(targetHost);
+        provider.setCredentials(authScope, new UsernamePasswordCredentials(DEFAULT_USER, DEFAULT_PASS_ARRAY));
         return provider;
     }
 
     private HttpContext context() {
-        final HttpHost targetHost = new HttpHost("localhost", 8082, "http");
+        final HttpHost targetHost = new HttpHost("http", "localhost", 8082);
-        final CredentialsProvider credsProvider = new BasicCredentialsProvider();
+        final BasicCredentialsProvider credsProvider = new BasicCredentialsProvider();
-        credsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(DEFAULT_USER, DEFAULT_PASS));
+        AuthScope authScope = new AuthScope(targetHost);
+        credsProvider.setCredentials(authScope, new UsernamePasswordCredentials(DEFAULT_USER, DEFAULT_PASS_ARRAY));
 
         // Create AuthCache instance
         final AuthCache authCache = new BasicAuthCache();

jackson-modules/jackson-annotations/README.md

@@ -8,3 +8,4 @@ This module contains articles about Jackson annotations.
 - [Jackson – Bidirectional Relationships](https://www.baeldung.com/jackson-bidirectional-relationships-and-infinite-recursion)
 - [Jackson JSON Views](https://www.baeldung.com/jackson-json-view-annotation)
 - [Deduction-Based Polymorphism in Jackson 2.12](https://www.baeldung.com/jackson-deduction-based-polymorphism)
+- [@JsonIgnore vs @Transient](https://www.baeldung.com/java-jsonignore-vs-transient)

jenkins-modules/jenkins-jobs/README.md

@@ -2,3 +2,4 @@
 - [Trigger Another Job from a Jenkins Pipeline](https://www.baeldung.com/ops/jenkins-pipeline-trigger-new-job)
 - [Fixing the “No Such DSL method” Error in Jenkins Pipeline](https://www.baeldung.com/ops/jenkins-pipeline-no-such-dsl-method-error)
 - [Jenkins Pipeline – Change to Another Folder](https://www.baeldung.com/ops/jenkins-pipeline-change-to-another-folder)
+- [How to Stop a Zombie Job on Jenkins Without Restarting the Server?](https://www.baeldung.com/ops/stop-zombie-job-on-jenkins-without-restarting-the-server)

jenkins-modules/jenkins-jobs/prevent-build-failure-job/pipeline-prevent-build-failure-job

@@ -0,0 +1,16 @@
+pipeline {
+    agent any
+    stages {
+        stage('tryCatch') {
+            steps {
+                script {
+                    try {
+                        sh 'test_script.sh'
+                    } catch (e) {
+                        echo "An error occurred: ${e}"
+                    }
+                }
+            }
+        }
+    }
+}

json-modules/json-2/src/main/java/com/baeldung/jsonvalidation/JacksonValidator.java

@@ -1,11 +1,15 @@
 package com.baeldung.jsonvalidation;
 
 import com.fasterxml.jackson.core.JacksonException;
+import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.json.JsonMapper;
 
 public class JacksonValidator {
 
-    final ObjectMapper mapper = new ObjectMapper();
+    final ObjectMapper mapper = JsonMapper.builder()
+        .enable(DeserializationFeature.FAIL_ON_TRAILING_TOKENS)
+        .build();
 
     public boolean isValid(String json) {
         try {

logging-modules/tinylog2/README.md

@@ -0,0 +1,2 @@
+## Relevant Articles
+- [Lightweight Logging With tinylog 2](https://www.baeldung.com/java-logging-tinylog-guide)

microservices-modules/rest-express/README.md

@@ -3,3 +3,4 @@
 This module contains articles about RestExpress.
 
 ### Relevant articles
+- [RESTful Microservices With RestExpress](https://www.baeldung.com/java-restexpress-guide)

persistence-modules/flyway/README.md

@@ -2,3 +2,4 @@
 - [Database Migrations with Flyway](http://www.baeldung.com/database-migrations-with-flyway)
 - [A Guide to Flyway Callbacks](http://www.baeldung.com/flyway-callbacks)
 - [Rolling Back Migrations with Flyway](https://www.baeldung.com/flyway-roll-back)
+- [Flyway Out of Order Migrations](https://www.baeldung.com/flyway-migrations)

persistence-modules/spring-data-elasticsearch/src/main/java/com/baeldung/spring/data/es/config/Config.java

@@ -6,17 +6,17 @@ import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.elasticsearch.client.ClientConfiguration;
 import org.springframework.data.elasticsearch.client.RestClients;
-import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
+import org.springframework.data.elasticsearch.config.AbstractElasticsearchConfiguration;
-import org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate;
 import org.springframework.data.elasticsearch.repository.config.EnableElasticsearchRepositories;
 
 @Configuration
 @EnableElasticsearchRepositories(basePackages = "com.baeldung.spring.data.es.repository")
 @ComponentScan(basePackages = { "com.baeldung.spring.data.es.service" })
-public class Config {
+public class Config extends AbstractElasticsearchConfiguration {
 
     @Bean
-    RestHighLevelClient client() {
+    @Override
+    public RestHighLevelClient elasticsearchClient() {
         ClientConfiguration clientConfiguration = ClientConfiguration.builder()
             .connectedTo("localhost:9200")
             .build();
@@ -24,9 +24,4 @@ public class Config {
         return RestClients.create(clientConfiguration)
             .rest();
     }
-
-    @Bean
-    public ElasticsearchOperations elasticsearchTemplate() {
-        return new ElasticsearchRestTemplate(client());
-    }
 }

persistence-modules/spring-data-elasticsearch/src/test/java/com/baeldung/spring/data/es/ElasticSearchManualTest.java

@@ -22,7 +22,7 @@ import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
-import org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate;
+import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
 import org.springframework.data.elasticsearch.core.SearchHits;
 import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
 import org.springframework.data.elasticsearch.core.query.NativeSearchQueryBuilder;
@@ -41,7 +41,7 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 public class ElasticSearchManualTest {
 
     @Autowired
-    private ElasticsearchRestTemplate elasticsearchTemplate;
+    private ElasticsearchOperations elasticsearchOperations;
 
     @Autowired
     private ArticleRepository articleRepository;
@@ -117,7 +117,7 @@ public class ElasticSearchManualTest {
         final Query searchQuery = new NativeSearchQueryBuilder().withFilter(regexpQuery("title", ".*data.*"))
             .build();
 
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(1, articles.getTotalHits());
     }
@@ -126,7 +126,7 @@ public class ElasticSearchManualTest {
     public void givenSavedDoc_whenTitleUpdated_thenCouldFindByUpdatedTitle() {
         final Query searchQuery = new NativeSearchQueryBuilder().withQuery(fuzzyQuery("title", "serch"))
             .build();
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(1, articles.getTotalHits());
 
@@ -147,7 +147,7 @@ public class ElasticSearchManualTest {
 
         final Query searchQuery = new NativeSearchQueryBuilder().withQuery(matchQuery("title", articleTitle).minimumShouldMatch("75%"))
             .build();
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(1, articles.getTotalHits());
         final long count = articleRepository.count();
@@ -162,7 +162,7 @@ public class ElasticSearchManualTest {
     public void givenSavedDoc_whenOneTermMatches_thenFindByTitle() {
         final Query searchQuery = new NativeSearchQueryBuilder().withQuery(matchQuery("title", "Search engines").operator(AND))
             .build();
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
         assertEquals(1, articles.getTotalHits());
     }
 }

persistence-modules/spring-data-elasticsearch/src/test/java/com/baeldung/spring/data/es/ElasticSearchQueryManualTest.java

@@ -39,7 +39,7 @@ import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate;
+import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
 import org.springframework.data.elasticsearch.core.SearchHits;
 import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
 import org.springframework.data.elasticsearch.core.query.NativeSearchQuery;
@@ -58,7 +58,7 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 public class ElasticSearchQueryManualTest {
 
     @Autowired
-    private ElasticsearchRestTemplate elasticsearchTemplate;
+    private ElasticsearchOperations elasticsearchOperations;
 
     @Autowired
     private ArticleRepository articleRepository;
@@ -101,7 +101,7 @@ public class ElasticSearchQueryManualTest {
     public void givenFullTitle_whenRunMatchQuery_thenDocIsFound() {
         final NativeSearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(matchQuery("title", "Search engines").operator(Operator.AND))
             .build();
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
         assertEquals(1, articles.getTotalHits());
     }
 
@@ -110,7 +110,7 @@ public class ElasticSearchQueryManualTest {
         final NativeSearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(matchQuery("title", "Engines Solutions"))
             .build();
 
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(1, articles.getTotalHits());
         assertEquals("Search engines", articles.getSearchHit(0)
@@ -123,7 +123,7 @@ public class ElasticSearchQueryManualTest {
         final NativeSearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(matchQuery("title", "elasticsearch data"))
             .build();
 
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(3, articles.getTotalHits());
     }
@@ -133,14 +133,14 @@ public class ElasticSearchQueryManualTest {
         NativeSearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(matchQuery("title.verbatim", "Second Article About Elasticsearch"))
             .build();
 
-        SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(1, articles.getTotalHits());
 
         searchQuery = new NativeSearchQueryBuilder().withQuery(matchQuery("title.verbatim", "Second Article About"))
             .build();
 
-        articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
         assertEquals(0, articles.getTotalHits());
     }
 
@@ -150,7 +150,7 @@ public class ElasticSearchQueryManualTest {
 
         final NativeSearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(builder)
             .build();
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(2, articles.getTotalHits());
     }
@@ -205,7 +205,7 @@ public class ElasticSearchQueryManualTest {
         final NativeSearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(matchPhraseQuery("title", "spring elasticsearch").slop(1))
             .build();
 
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(1, articles.getTotalHits());
     }
@@ -217,7 +217,7 @@ public class ElasticSearchQueryManualTest {
             .prefixLength(3))
             .build();
 
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(1, articles.getTotalHits());
     }
@@ -229,7 +229,7 @@ public class ElasticSearchQueryManualTest {
             .type(MultiMatchQueryBuilder.Type.BEST_FIELDS))
             .build();
 
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(2, articles.getTotalHits());
     }
@@ -241,7 +241,7 @@ public class ElasticSearchQueryManualTest {
 
         final NativeSearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(builder)
             .build();
-        final SearchHits<Article> articles = elasticsearchTemplate.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
+        final SearchHits<Article> articles = elasticsearchOperations.search(searchQuery, Article.class, IndexCoordinates.of("blog"));
 
         assertEquals(2, articles.getTotalHits());
     }

persistence-modules/spring-data-jpa-repo-2/README.md

@@ -7,4 +7,5 @@
 - [LIKE Queries in Spring JPA Repositories](https://www.baeldung.com/spring-jpa-like-queries)
 - [How to Access EntityManager with Spring Data](https://www.baeldung.com/spring-data-entitymanager)
 - [Difference Between JPA and Spring Data JPA](https://www.baeldung.com/spring-data-jpa-vs-jpa)
+- [Differences Between Spring Data JPA findFirst() and findTop()](https://www.baeldung.com/spring-data-jpa-findfirst-vs-findtop)
 - More articles: [[<-- prev]](../spring-data-jpa-repo)

persistence-modules/spring-data-jpa-repo-2/src/main/java/com/baeldung/spring/data/persistence/search/Student.java

@@ -0,0 +1,75 @@
+package com.baeldung.spring.data.persistence.search;
+
+import java.util.Objects;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class Student {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private long id;
+
+    private String name;
+    private int score;
+
+    public Student() {
+    }
+
+    public Student(String name, int score) {
+
+        this.name = name;
+        this.score = score;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getScore() {
+        return score;
+    }
+
+    public void setScore(int score) {
+        this.score = score;
+    }
+
+    @Override
+    public String toString() {
+        return "Student [id=" + id + ", name=" + name + ", score=" + score + "]";
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, name, score);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        Student other = (Student) obj;
+        return id == other.id && Objects.equals(name, other.name) && score == other.score;
+    }
+
+}

persistence-modules/spring-data-jpa-repo-2/src/main/java/com/baeldung/spring/data/persistence/search/StudentApplication.java

@@ -0,0 +1,16 @@
+package com.baeldung.spring.data.persistence.search;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class StudentApplication {
+
+    private static final Logger log = LoggerFactory.getLogger(StudentApplication.class);
+
+    public static void main(String[] args) {
+        SpringApplication.run(StudentApplication.class, args);
+    }
+}

persistence-modules/spring-data-jpa-repo-2/src/main/java/com/baeldung/spring/data/persistence/search/StudentRepository.java

@@ -0,0 +1,31 @@
+package com.baeldung.spring.data.persistence.search;
+
+import java.util.List;
+
+import org.springframework.data.domain.Sort;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface StudentRepository extends JpaRepository<Student, Long> {
+
+    Student findFirstByOrderByScoreDesc();
+
+    Student findFirstBy(Sort sort);
+
+    Student findFirstByNameLike(String name, Sort sort);
+
+    List<Student> findFirst3ByOrderByScoreDesc();
+
+    List<Student> findFirst2ByScoreBetween(int startScore, int endScore, Sort sort);
+
+    Student findTopByOrderByScoreDesc();
+
+    Student findTopBy(Sort sort);
+
+    Student findTopByNameLike(String name, Sort sort);
+
+    List<Student> findTop3ByOrderByScoreDesc();
+
+    List<Student> findTop2ByScoreBetween(int startScore, int endScore, Sort sort);
+}

persistence-modules/spring-data-jpa-repo-2/src/main/resources/application.properties

@@ -3,3 +3,4 @@ spring.datasource.username=sa
 spring.datasource.password=sa
 
 spring.jpa.properties.hibernate.globally_quoted_identifiers=true
+logging.level.com.baeldung.spring.data.persistence.search=debug

persistence-modules/spring-data-jpa-repo-2/src/test/java/com/baeldung/spring/data/persistence/search/StudentApplicationUnitTest.java

@@ -0,0 +1,100 @@
+package com.baeldung.spring.data.persistence.search;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.Collectors;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.data.domain.Sort;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class StudentApplicationUnitTest {
+
+    @Autowired
+    private StudentRepository studentRepo;
+    private List<Student> students;
+
+    @Before
+    public void fillData() {
+        students = new ArrayList<>();
+        int count = 10;
+        Random r = new Random();
+        List<Integer> scores = r.ints(0, 101)
+          .distinct()
+          .limit(count)
+          .boxed()
+          .collect(Collectors.toList());
+
+        for (int i = 0; i < count; i++) {
+            Integer score = scores.get(i);
+            Student s = new Student("Student-" + i, score);
+            students.add(s);
+        }
+
+        studentRepo.saveAll(students);
+        Comparator<Student> c = Comparator.comparing(a -> a.getScore());
+        c = c.reversed();
+        students.sort(c);
+    }
+
+    @After
+    public void clearData() {
+        studentRepo.deleteAll();
+    }
+
+    @Test
+    public void givenStudentScores_whenMoreThanOne_thenFindFirst() {
+
+        Student student = studentRepo.findFirstByOrderByScoreDesc();
+        Student s = students.get(0);
+        assertEquals(student, s);
+    }
+
+    @Test
+    public void givenStudentScores_whenMoreThan3_thenFindFirstThree() {
+
+        List<Student> firstThree = studentRepo.findFirst3ByOrderByScoreDesc();
+        List<Student> sList = students.subList(0, 3);
+        assertArrayEquals(firstThree.toArray(), sList.toArray());
+    }
+
+    @Test
+    public void givenStudentScores_whenNameMatches_thenFindFirstStudent() {
+
+        String matchString = "3";
+        Student student = studentRepo.findFirstByNameLike("%" + matchString + "%", Sort.by("score")
+          .descending());
+        Student s = students.stream()
+          .filter(a -> a.getName()
+          .contains(matchString))
+          .findFirst()
+          .orElse(null);
+        assertEquals(student, s);
+    }
+
+    @Test
+    public void givenStudentScores_whenBetweenRange_thenFindFirstTwoStudents() {
+
+        List<Student> topTwoBetweenRange = studentRepo.findFirst2ByScoreBetween(50, 60, Sort.by("score")
+          .descending());
+        List<Student> _students = students.stream()
+          .filter(a -> a.getScore() >= 50 && a.getScore() <= 60)
+          .limit(2)
+          .collect(Collectors.toList());
+        assertArrayEquals(_students.toArray(), topTwoBetweenRange.toArray());
+    }
+}

pom.xml

@@ -1133,6 +1133,7 @@
                  <!-- <module>core-java-modules/core-java-19</module> --> <!-- uses preview features, to be decided how to handle -->
                  <module>core-java-modules/core-java-collections-set</module>
                  <module>core-java-modules/core-java-collections-list-4</module>
+                 <module>core-java-modules/core-java-collections-array-list</module>
                  <module>core-java-modules/core-java-collections-maps-4</module>
                  <module>core-java-modules/core-java-collections-maps-5</module>
                  <module>core-java-modules/core-java-concurrency-simple</module>

spring-boot-modules/spring-boot-keycloak-adapters/README.md

@@ -0,0 +1,7 @@
+## Spring Boot Keycloak
+
+This module contains articles about Keycloak in Spring Boot projects.
+
+## Relevant articles:
+- [Custom User Attributes with Keycloak](https://www.baeldung.com/keycloak-custom-user-attributes)
+- [Get Keycloak User ID in Spring](https://www.baeldung.com/spring-keycloak-get-user-id)

spring-boot-modules/spring-boot-keycloak-adapters/pom.xml

@@ -0,0 +1,91 @@
+<?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>
+    <groupId>com.baeldung.keycloak</groupId>
+    <artifactId>spring-boot-keycloak-adapters</artifactId>
+    <version>0.0.1</version>
+    <name>spring-boot-keycloak-adapters</name>
+    <packaging>jar</packaging>
+    <description>This is a simple application demonstrating integration between Keycloak and Spring Boot.</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-boot-2</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-2</relativePath>
+    </parent>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.keycloak.bom</groupId>
+                <artifactId>keycloak-adapter-bom</artifactId>
+                <version>${keycloak-adapter-bom.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.keycloak</groupId>
+            <artifactId>keycloak-spring-boot-starter</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-oauth2-client</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-security</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.hsqldb</groupId>
+            <artifactId>hsqldb</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-thymeleaf</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <keycloak-adapter-bom.version>15.0.2</keycloak-adapter-bom.version>
+    </properties>
+
+</project>

spring-boot-modules/spring-boot-keycloak-adapters/src/main/java/com/baeldung/keycloak/Customer.java

@@ -0,0 +1,49 @@
+package com.baeldung.keycloak;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class Customer {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private long id;
+    private String name;
+    private String serviceRendered;
+    private String address;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getServiceRendered() {
+        return serviceRendered;
+    }
+
+    public void setServiceRendered(String serviceRendered) {
+        this.serviceRendered = serviceRendered;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+
+}

spring-boot-modules/spring-boot-keycloak-adapters/src/main/java/com/baeldung/keycloak/CustomerDAO.java

@@ -0,0 +1,7 @@
+package com.baeldung.keycloak;
+
+import org.springframework.data.repository.CrudRepository;
+
+public interface CustomerDAO extends CrudRepository<Customer, Long> {
+
+}

spring-boot-modules/spring-boot-keycloak-adapters/src/main/java/com/baeldung/keycloak/KeycloakLogoutHandler.java

@@ -0,0 +1,45 @@
+package com.baeldung.keycloak;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.oauth2.core.oidc.user.OidcUser;
+import org.springframework.security.web.authentication.logout.LogoutHandler;
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestTemplate;
+import org.springframework.web.util.UriComponentsBuilder;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@Component
+public class KeycloakLogoutHandler implements LogoutHandler {
+
+    private static final Logger logger = LoggerFactory.getLogger(KeycloakLogoutHandler.class);
+    private final RestTemplate restTemplate;
+
+    public KeycloakLogoutHandler(RestTemplate restTemplate) {
+        this.restTemplate = restTemplate;
+    }
+
+    @Override
+    public void logout(HttpServletRequest request, HttpServletResponse response, Authentication auth) {
+        logoutFromKeycloak((OidcUser) auth.getPrincipal());
+    }
+
+    private void logoutFromKeycloak(OidcUser user) {
+        String endSessionEndpoint = user.getIssuer() + "/protocol/openid-connect/logout";
+        UriComponentsBuilder builder = UriComponentsBuilder
+          .fromUriString(endSessionEndpoint)
+          .queryParam("id_token_hint", user.getIdToken().getTokenValue());
+
+        ResponseEntity<String> logoutResponse = restTemplate.getForEntity(builder.toUriString(), String.class);
+        if (logoutResponse.getStatusCode().is2xxSuccessful()) {
+            logger.info("Successfulley logged out from Keycloak");
+        } else {
+            logger.error("Could not propagate logout to Keycloak");
+        }
+    }
+
+}

spring-boot-modules/spring-boot-keycloak-adapters/src/main/java/com/baeldung/keycloak/SecurityConfig.java

@@ -0,0 +1,41 @@
+package com.baeldung.keycloak;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.core.session.SessionRegistryImpl;
+import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.security.web.authentication.session.RegisterSessionAuthenticationStrategy;
+import org.springframework.security.web.authentication.session.SessionAuthenticationStrategy;
+
+@Configuration
+@EnableWebSecurity
+class SecurityConfig {
+
+    private final KeycloakLogoutHandler keycloakLogoutHandler;
+
+    SecurityConfig(KeycloakLogoutHandler keycloakLogoutHandler) {
+        this.keycloakLogoutHandler = keycloakLogoutHandler;
+    }
+
+    @Bean
+    protected SessionAuthenticationStrategy sessionAuthenticationStrategy() {
+        return new RegisterSessionAuthenticationStrategy(new SessionRegistryImpl());
+    }
+
+    @Bean
+    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
+        http.authorizeRequests()
+            .antMatchers("/customers*", "/users*")
+            .hasRole("USER")
+            .anyRequest()
+            .permitAll();
+        http.oauth2Login()
+            .and()
+            .logout()
+            .addLogoutHandler(keycloakLogoutHandler)
+            .logoutSuccessUrl("/");
+        return http.build();
+    }
+}

spring-boot-modules/spring-boot-keycloak-adapters/src/main/java/com/baeldung/keycloak/SpringBoot.java

@@ -0,0 +1,20 @@
+package com.baeldung.keycloak;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.web.client.RestTemplate;
+
+@SpringBootApplication
+
+public class SpringBoot {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SpringBoot.class, args);
+    }
+
+    @Bean
+    public RestTemplate restTemplate() {
+        return new RestTemplate();
+    }
+}

spring-boot-modules/spring-boot-keycloak-adapters/src/main/java/com/baeldung/keycloak/WebController.java

@@ -0,0 +1,60 @@
+package com.baeldung.keycloak;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+
+import java.security.Principal;
+
+import org.springframework.beans.factory.annotation.Autowired;
+
+import javax.servlet.http.HttpServletRequest;
+
+@Controller
+public class WebController {
+
+    @Autowired
+    private CustomerDAO customerDAO;
+
+    @GetMapping(path = "/")
+    public String index() {
+        return "external";
+    }
+
+    @GetMapping("/logout")
+    public String logout(HttpServletRequest request) throws Exception {
+        request.logout();
+        return "redirect:/";
+    }
+
+    @GetMapping(path = "/customers")
+    public String customers(Principal principal, Model model) {
+        addCustomers();
+        Iterable<Customer> customers = customerDAO.findAll();
+        model.addAttribute("customers", customers);
+        model.addAttribute("username", principal.getName());
+        return "customers";
+    }
+
+    // add customers for demonstration
+    public void addCustomers() {
+
+        Customer customer1 = new Customer();
+        customer1.setAddress("1111 foo blvd");
+        customer1.setName("Foo Industries");
+        customer1.setServiceRendered("Important services");
+        customerDAO.save(customer1);
+
+        Customer customer2 = new Customer();
+        customer2.setAddress("2222 bar street");
+        customer2.setName("Bar LLP");
+        customer2.setServiceRendered("Important services");
+        customerDAO.save(customer2);
+
+        Customer customer3 = new Customer();
+        customer3.setAddress("33 main street");
+        customer3.setName("Big LLC");
+        customer3.setServiceRendered("Important services");
+        customerDAO.save(customer3);
+    }
+}

spring-boot-modules/spring-boot-keycloak-adapters/src/main/resources/application.properties

@@ -0,0 +1,15 @@
+### server port
+server.port=8081
+
+#Keycloak Configuration
+keycloak.auth-server-url=http://localhost:8180/auth
+keycloak.realm=SpringBootKeycloak
+keycloak.resource=login-app
+keycloak.public-client=true
+keycloak.principal-attribute=preferred_username
+
+spring.security.oauth2.client.registration.keycloak.client-id=login-app
+spring.security.oauth2.client.registration.keycloak.authorization-grant-type=authorization_code
+spring.security.oauth2.client.registration.keycloak.scope=openid
+spring.security.oauth2.client.provider.keycloak.issuer-uri=http://localhost:8180/auth/realms/SpringBootKeycloak
+spring.security.oauth2.client.provider.keycloak.user-name-attribute=preferred_username

spring-boot-modules/spring-boot-keycloak-adapters/src/main/resources/logback.xml

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

spring-boot-modules/spring-boot-keycloak-adapters/src/main/resources/templates/customers.html

@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<html xmlns:th="http://www.thymeleaf.org">
+<head th:include="layout :: headerFragment">
+</head>
+<body>
+	<div id="container">
+		<h1>
+			Hello, <span th:text="${username}">--name--</span>.
+		</h1>
+		<table class="table table-striped">
+			<thead>
+				<tr>
+					<th>ID</th>
+					<th>Name</th>
+					<th>Address</th>
+					<th>Service Rendered</th>
+				</tr>
+			</thead>
+			<tbody>
+				<tr th:each="customer : ${customers}">
+					<td th:text="${customer.id}">Text ...</td>
+					<td th:text="${customer.name}">Text ...</td>
+					<td th:text="${customer.address}">Text ...</td>
+					<td th:text="${customer.serviceRendered}">Text...</td>
+				</tr>
+			</tbody>
+		</table>
+		<div id="pagefoot" th:include="layout :: footerFragment">Footer
+		</div>
+		<a href="/logout">Logout</a>
+	</div>
+	<!-- container -->
+</body>
+</html>

spring-boot-modules/spring-boot-keycloak-adapters/src/main/resources/templates/external.html

@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html xmlns:th="http://www.thymeleaf.org">
+<head th:include="layout :: headerFragment">
+</head>
+<body>
+	<div class="container">
+		<div class="jumbotron text-center">
+			<h1>Customer Portal</h1>
+		</div>
+		<div>
+			<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam
+				erat lectus, vehicula feugiat ultricies at, tempus sed ante. Cras
+				arcu erat, lobortis vitae quam et, mollis pharetra odio. Nullam sit
+				amet congue ipsum. Nunc dapibus odio ut ligula venenatis porta non
+				id dui. Duis nec tempor tellus. Suspendisse id blandit ligula, sit
+				amet varius mauris. Nulla eu eros pharetra, tristique dui quis,
+				vehicula libero. Aenean a neque sit amet tellus porttitor rutrum nec
+				at leo.</p>
+
+			<h2>Existing Customers</h2>
+			<div class="well">
+				<b>Enter the intranet: </b><a th:href="@{/customers}">customers</a>
+			</div>
+		</div>
+		<div id="pagefoot" th:include="layout :: footerFragment">Footer
+		</div>
+	</div>
+	<!-- container -->
+
+</body>
+</html>

spring-boot-modules/spring-boot-keycloak-adapters/src/main/resources/templates/layout.html

@@ -0,0 +1,18 @@
+
+<head th:fragment="headerFragment">
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+<title>Customer Portal</title>
+<link
+	href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css"
+	rel="stylesheet"
+	integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u"
+	crossorigin="anonymous"></link>
+<link
+	href="https://cdn.datatables.net/1.10.16/css/jquery.dataTables.min.css"
+	rel="stylesheet"></link>
+</head>
+
+<div id="pagefoot" th:fragment="footerFragment">
+	<p>Document last modified 2017/10/23.</p>
+	<p>Copyright: Lorem Ipsum</p>
+</div>

spring-boot-modules/spring-boot-keycloak/README.md

@@ -4,9 +4,8 @@ This module contains articles about Keycloak in Spring Boot projects.
 
 ## Relevant articles:
 - [A Quick Guide to Using Keycloak With Spring Boot](https://www.baeldung.com/spring-boot-keycloak)
-- [Custom User Attributes with Keycloak](https://www.baeldung.com/keycloak-custom-user-attributes)
 - [Customizing the Login Page for Keycloak](https://www.baeldung.com/keycloak-custom-login-page)
 - [Keycloak User Self-Registration](https://www.baeldung.com/keycloak-user-registration)
 - [Customizing Themes for Keycloak](https://www.baeldung.com/spring-keycloak-custom-themes)
 - [Securing SOAP Web Services With Keycloak](https://www.baeldung.com/soap-keycloak)
-- [Get Keycloak User ID in Spring](https://www.baeldung.com/spring-keycloak-get-user-id)
+

spring-boot-modules/spring-boot-keycloak/pom.xml

@@ -17,26 +17,14 @@
         <relativePath>../../parent-boot-2</relativePath>
     </parent>
 
-    <dependencyManagement>
-        <dependencies>
-            <dependency>
-                <groupId>org.keycloak.bom</groupId>
-                <artifactId>keycloak-adapter-bom</artifactId>
-                <version>${keycloak-adapter-bom.version}</version>
-                <type>pom</type>
-                <scope>import</scope>
-            </dependency>
-        </dependencies>
-    </dependencyManagement>
-
     <dependencies>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter</artifactId>
         </dependency>
         <dependency>
-            <groupId>org.keycloak</groupId>
+            <groupId>org.springframework.boot</groupId>
-            <artifactId>keycloak-spring-boot-starter</artifactId>
+            <artifactId>spring-boot-starter-oauth2-resource-server</artifactId>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
@@ -113,8 +101,4 @@
         </plugins>
     </build>
 
-    <properties>
-        <keycloak-adapter-bom.version>15.0.2</keycloak-adapter-bom.version>
-    </properties>
-
 </project>

spring-boot-modules/spring-boot-keycloak/src/main/java/com/baeldung/keycloak/SecurityConfig.java

@@ -2,8 +2,11 @@ package com.baeldung.keycloak;
 
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.security.authentication.AuthenticationManager;
+import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
 import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.annotation.web.configurers.oauth2.server.resource.OAuth2ResourceServerConfigurer;
 import org.springframework.security.core.session.SessionRegistryImpl;
 import org.springframework.security.web.SecurityFilterChain;
 import org.springframework.security.web.authentication.session.RegisterSessionAuthenticationStrategy;
@@ -36,6 +39,13 @@ class SecurityConfig {
             .logout()
             .addLogoutHandler(keycloakLogoutHandler)
             .logoutSuccessUrl("/");
+        http.oauth2ResourceServer(OAuth2ResourceServerConfigurer::jwt);
         return http.build();
     }
+
+    @Bean
+    public AuthenticationManager authenticationManager(HttpSecurity http) throws Exception {
+        return http.getSharedObject(AuthenticationManagerBuilder.class)
+            .build();
+    }
 }

spring-boot-modules/spring-boot-keycloak/src/main/java/com/baeldung/keycloaksoap/KeycloakSecurityConfig.java

@@ -1,54 +1,27 @@
 package com.baeldung.keycloaksoap;
 
-import org.keycloak.adapters.KeycloakConfigResolver;
-import org.keycloak.adapters.springboot.KeycloakSpringBootConfigResolver;
-import org.keycloak.adapters.springsecurity.KeycloakConfiguration;
-import org.keycloak.adapters.springsecurity.authentication.KeycloakAuthenticationProvider;
-import org.keycloak.adapters.springsecurity.config.KeycloakWebSecurityConfigurerAdapter;
-import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.context.annotation.Bean;
-import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.security.config.annotation.method.configuration.EnableGlobalMethodSecurity;
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
-import org.springframework.security.core.authority.mapping.SimpleAuthorityMapper;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
-import org.springframework.security.core.session.SessionRegistryImpl;
+import org.springframework.security.config.annotation.web.configurers.oauth2.server.resource.OAuth2ResourceServerConfigurer;
-import org.springframework.security.web.authentication.session.RegisterSessionAuthenticationStrategy;
+import org.springframework.security.web.SecurityFilterChain;
-import org.springframework.security.web.authentication.session.SessionAuthenticationStrategy;
 
-@KeycloakConfiguration
+@Configuration
+@EnableWebSecurity
 @ConditionalOnProperty(name = "keycloak.enabled", havingValue = "true")
 @EnableGlobalMethodSecurity(jsr250Enabled = true)
-public class KeycloakSecurityConfig extends KeycloakWebSecurityConfigurerAdapter {
+public class KeycloakSecurityConfig {
-    @Override
+
-    protected void configure(HttpSecurity http) throws Exception {
+    @Bean
-        super.configure(http);
+    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
-        //@formatter:off
+        http.csrf()
-        http
-          .csrf()
             .disable()
-          .authorizeRequests()
+            .authorizeHttpRequests(auth -> auth.anyRequest()
-          .anyRequest()
+                .authenticated())
-          .permitAll();
+            .oauth2ResourceServer(OAuth2ResourceServerConfigurer::jwt);
-        //@formatter:on
+        return http.build();
     }
-
-    @Autowired
-    public void configureGlobal(AuthenticationManagerBuilder auth) {
-        KeycloakAuthenticationProvider keycloakAuthenticationProvider = keycloakAuthenticationProvider();
-        keycloakAuthenticationProvider.setGrantedAuthoritiesMapper(new SimpleAuthorityMapper());
-        auth.authenticationProvider(keycloakAuthenticationProvider);
-    }
-
-    @Bean
-    @Override
-    protected SessionAuthenticationStrategy sessionAuthenticationStrategy() {
-        return new RegisterSessionAuthenticationStrategy(new SessionRegistryImpl());
-    }
-
-    @Bean
-    public KeycloakConfigResolver keycloakSpringBootConfigResolver() {
-        return new KeycloakSpringBootConfigResolver();
-    }
-
 }

spring-boot-modules/spring-boot-keycloak/src/main/resources/application-keycloak.properties

@@ -1,14 +1,8 @@
 server.port=18080
 
 keycloak.enabled=true
-keycloak.realm=baeldung-soap-services
-keycloak.auth-server-url=http://localhost:8080/auth
-keycloak.bearer-only=true
-keycloak.credentials.secret=14da6f9e-261f-489a-9bf0-1441e4a9ddc4
-keycloak.ssl-required=external
-keycloak.resource=baeldung-soap-services
-keycloak.use-resource-role-mappings=true
 
+spring.security.oauth2.resourceserver.jwt.issuer-uri=http://localhost:8080/realms/baeldung-soap-services
 
 # Custom properties begin here
 ws.api.path=/ws/api/v1/*

spring-boot-modules/spring-boot-keycloak/src/main/resources/application.properties

@@ -1,15 +1,10 @@
 ### server port
 server.port=8081
 
-#Keycloak Configuration
-keycloak.auth-server-url=http://localhost:8180/auth
-keycloak.realm=SpringBootKeycloak
-keycloak.resource=login-app
-keycloak.public-client=true
-keycloak.principal-attribute=preferred_username
-
 spring.security.oauth2.client.registration.keycloak.client-id=login-app
 spring.security.oauth2.client.registration.keycloak.authorization-grant-type=authorization_code
 spring.security.oauth2.client.registration.keycloak.scope=openid
-spring.security.oauth2.client.provider.keycloak.issuer-uri=http://localhost:8180/auth/realms/SpringBootKeycloak
+spring.security.oauth2.client.provider.keycloak.issuer-uri=http://localhost:8080/realms/SpringBootKeycloak
 spring.security.oauth2.client.provider.keycloak.user-name-attribute=preferred_username
+
+spring.security.oauth2.resourceserver.jwt.issuer-uri=http://localhost:8080/realms/SpringBootKeycloak

spring-boot-modules/spring-boot-keycloak/src/test/java/com/baeldung/keycloak/KeycloakContextIntegrationTest.java

@@ -0,0 +1,18 @@
+package com.baeldung.keycloak;
+
+import org.junit.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import com.baeldung.keycloak.SpringBoot;
+
+@ExtendWith(SpringExtension.class)
+@SpringBootTest(classes = { SpringBoot.class })
+public class KeycloakContextIntegrationTest {
+
+    @Test
+    public void whenLoadApplication_thenSuccess() {
+
+    }
+
+}

spring-boot-modules/spring-boot-keycloak/src/test/java/com/baeldung/keycloaksoap/KeycloakSoapLiveTest.java

@@ -105,7 +105,7 @@ class KeycloakSoapLiveTest {
     void givenAccessToken_whenDeleteProduct_thenReturnSuccess() {
         HttpHeaders headers = new HttpHeaders();
         headers.set("content-type", "text/xml");
-        headers.set("Authorization", "Bearer " + generateToken("jhondoe", "password"));
+        headers.set("Authorization", "Bearer " + generateToken("johndoe", "password"));
         HttpEntity<String> request = new HttpEntity<>(Utility.getDeleteProductsRequest(), headers);
         ResponseEntity<String> responseEntity = restTemplate.postForEntity("http://localhost:" + port + "/ws/api/v1/", request, String.class);
 

spring-boot-modules/spring-boot-keycloak/src/test/resources/application-test.properties

@@ -1,4 +1,7 @@
 grant.type=password
 client.id=baeldung-soap-services
 client.secret=d2ba7af8-f7d2-4c97-b4a5-3c88b59920ae
-url=http://localhost:8080/auth/realms/baeldung-soap-services/protocol/openid-connect/token
+url=http://localhost:8080/realms/baeldung-soap-services/protocol/openid-connect/token
+
+keycloak.enabled=true
+spring.security.oauth2.resourceserver.jwt.issuer-uri=http://localhost:8080/realms/baeldung-soap-services

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/requestheader/BuzzController.java

@@ -0,0 +1,21 @@
+package com.baeldung.requestheader;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.requestheader.interceptor.OperatorHolder;
+
+@RestController
+public class BuzzController {
+    private final OperatorHolder operatorHolder;
+
+    public BuzzController(OperatorHolder operatorHolder) {
+        this.operatorHolder = operatorHolder;
+    }
+
+    @GetMapping("buzz")
+    public String buzz() {
+        return "hello, " + operatorHolder.getOperator();
+    }
+
+}

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/requestheader/FooBarController.java

@@ -0,0 +1,22 @@
+package com.baeldung.requestheader;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestHeader;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class FooBarController {
+
+    @GetMapping("foo")
+    public String foo(HttpServletRequest request) {
+        String operator = request.getHeader("operator");
+        return "hello, " + operator;
+    }
+
+    @GetMapping("bar")
+    public String bar(@RequestHeader("operator") String operator) {
+        return "hello, " + operator;
+    }
+}

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/requestheader/HeaderInterceptorApplication.java

@@ -0,0 +1,15 @@
+package com.baeldung.requestheader;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+
+@SpringBootApplication
+@EnableWebMvc
+public class HeaderInterceptorApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(HeaderInterceptorApplication.class, args);
+    }
+
+}

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/requestheader/config/HeaderInterceptorConfig.java

@@ -0,0 +1,33 @@
+package com.baeldung.requestheader.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Scope;
+import org.springframework.context.annotation.ScopedProxyMode;
+import org.springframework.web.context.WebApplicationContext;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+import com.baeldung.requestheader.interceptor.OperatorHolder;
+import com.baeldung.requestheader.interceptor.OperatorInterceptor;
+
+@Configuration
+public class HeaderInterceptorConfig implements WebMvcConfigurer {
+
+    @Override
+    public void addInterceptors(final InterceptorRegistry registry) {
+        registry.addInterceptor(operatorInterceptor());
+    }
+
+    @Bean
+    public OperatorInterceptor operatorInterceptor() {
+        return new OperatorInterceptor(operatorHolder());
+    }
+
+    @Bean
+    @Scope(value = WebApplicationContext.SCOPE_REQUEST, proxyMode = ScopedProxyMode.TARGET_CLASS)
+    public OperatorHolder operatorHolder() {
+        return new OperatorHolder();
+    }
+
+}

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/requestheader/interceptor/OperatorHolder.java

@@ -0,0 +1,13 @@
+package com.baeldung.requestheader.interceptor;
+
+public class OperatorHolder {
+    private String operator;
+
+    public String getOperator() {
+        return operator;
+    }
+
+    public void setOperator(String operator) {
+        this.operator = operator;
+    }
+}

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/requestheader/interceptor/OperatorInterceptor.java

@@ -0,0 +1,22 @@
+package com.baeldung.requestheader.interceptor;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.web.servlet.HandlerInterceptor;
+
+public class OperatorInterceptor implements HandlerInterceptor {
+
+    private final OperatorHolder operatorHolder;
+
+    @Override
+    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
+        String operator = request.getHeader("operator");
+        operatorHolder.setOperator(operator);
+        return true;
+    }
+
+    public OperatorInterceptor(OperatorHolder operatorHolder) {
+        this.operatorHolder = operatorHolder;
+    }
+}

spring-boot-modules/spring-boot-mvc-5/src/test/java/com/baeldung/requestheader/HeaderInterceptorIntegrationTest.java

@@ -0,0 +1,65 @@
+package com.baeldung.requestheader;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.test.context.web.WebAppConfiguration;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import org.springframework.web.context.WebApplicationContext;
+
+@ExtendWith(SpringExtension.class)
+@ContextConfiguration(classes = { HeaderInterceptorApplication.class })
+@WebAppConfiguration
+public class HeaderInterceptorIntegrationTest {
+
+    @Autowired
+    private WebApplicationContext webApplicationContext;
+
+    private MockMvc mockMvc;
+
+    @BeforeEach
+    public void setup() {
+        this.mockMvc = MockMvcBuilders.webAppContextSetup(this.webApplicationContext)
+          .build();
+    }
+
+    @Test
+    public void givenARequestWithOperatorHeader_whenWeCallFooEndpoint_thenOperatorIsExtracted() throws Exception {
+        MockHttpServletResponse response = this.mockMvc.perform(get("/foo").header("operator", "John.Doe"))
+          .andDo(print())
+          .andReturn()
+          .getResponse();
+
+        assertThat(response.getContentAsString()).isEqualTo("hello, John.Doe");
+    }
+
+    @Test
+    public void givenARequestWithOperatorHeader_whenWeCallBarEndpoint_thenOperatorIsExtracted() throws Exception {
+        MockHttpServletResponse response = this.mockMvc.perform(get("/bar").header("operator", "John.Doe"))
+          .andDo(print())
+          .andReturn()
+          .getResponse();
+
+        assertThat(response.getContentAsString()).isEqualTo("hello, John.Doe");
+    }
+
+    @Test
+    public void givenARequestWithOperatorHeader_whenWeCallBuzzEndpoint_thenOperatorIsIntercepted() throws Exception {
+        MockHttpServletResponse response = this.mockMvc.perform(get("/buzz").header("operator", "John.Doe"))
+          .andDo(print())
+          .andReturn()
+          .getResponse();
+
+        assertThat(response.getContentAsString()).isEqualTo("hello, John.Doe");
+    }
+
+}

spring-boot-modules/spring-boot-swagger-keycloak/src/main/resources/application.yml

@@ -2,7 +2,6 @@ keycloak:
   auth-server-url: https://api.example.com/auth # Keycloak server url
   realm: todos-service-realm # Keycloak Realm
   resource: todos-service-clients # Keycloak Client
-  public-client: true
   principal-attribute: preferred_username
   ssl-required: external
   credentials:

spring-kafka-2/README.md

@@ -4,4 +4,4 @@ This module contains articles about Spring with Kafka
 
 ### Relevant articles
 
-- [Implementing Retry In Kafka Consumer]
+- [Implementing Retry In Kafka Consumer](https://www.baeldung.com/spring-retry-kafka-consumer)

spring-scheduling/src/main/java/com/baeldung/async/config/SpringAsyncConfig.java

@@ -24,7 +24,9 @@ public class SpringAsyncConfig implements AsyncConfigurer {
 
     @Override
     public Executor getAsyncExecutor() {
-        return new SimpleAsyncTaskExecutor();
+        ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
+        threadPoolTaskExecutor.initialize();
+        return threadPoolTaskExecutor;
     }
 
     @Override

spring-security-modules/spring-security-saml/src/main/resources/application.properties

@@ -1,9 +1,9 @@
-saml.keystore.location=classpath:/saml/saml-keystore
+saml.keystore.location=classpath:/saml/saml-keystore.jks
 # Password for Java keystore and item therein
-saml.keystore.password=<key_pass>
+saml.keystore.password=baeldungsamlokta
-saml.keystore.alias=<key_alias>
+saml.keystore.alias=baeldungspringsaml
 
 # SAML Entity ID extracted from top of SAML metadata file
-saml.idp=<idp_issuer_url>
+saml.idp=http://www.okta.com/exk26fxqrz8LLk9dV4x7
 saml.sp=http://localhost:8080/saml/metadata
 spring.main.allow-circular-references=true

spring-security-modules/spring-security-web-angular/spring-security-web-angular-server/src/main/java/com/baeldung/springbootsecurityrest/basicauth/config/BasicAuthConfiguration.java

@@ -1,5 +1,7 @@
 package com.baeldung.springbootsecurityrest.basicauth.config;
 
+import static org.springframework.security.config.Customizer.withDefaults;
+
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.http.HttpMethod;
@@ -27,6 +29,7 @@ public class BasicAuthConfiguration {
     public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
         http.csrf()
             .disable()
+            .cors(withDefaults())
             .authorizeRequests()
             .antMatchers(HttpMethod.OPTIONS, "/**")
             .permitAll()

spring-web-modules/spring-web-url/README.md

@@ -6,3 +6,4 @@ This module contains articles about Spring MVC
 - [Using a Slash Character in Spring URLs](https://www.baeldung.com/spring-slash-character-in-url)
 - [Excluding URLs for a Filter in a Spring Web Application](https://www.baeldung.com/spring-exclude-filter)
 - [Handling URL Encoded Form Data in Spring REST](https://www.baeldung.com/spring-url-encoded-form-data)
+- [Spring MVC – Mapping the Root URL to a Page](https://www.baeldung.com/spring-mvc-map-root-url)

spring-web-modules/spring-web-url/src/main/java/com/baeldung/rootmapping/RootMappingApplication.java

@@ -0,0 +1,14 @@
+package com.baeldung.rootmapping;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+
+@SpringBootApplication
+@EnableWebMvc
+public class RootMappingApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(RootMappingApplication.class, args);
+    }
+}

spring-web-modules/spring-web-url/src/main/java/com/baeldung/rootmapping/config/WebConfig.java

@@ -0,0 +1,13 @@
+package com.baeldung.rootmapping.config;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+@Configuration
+public class WebConfig implements WebMvcConfigurer {
+    @Override
+    public void addViewControllers(ViewControllerRegistry registry) {
+        registry.addViewController("/").setViewName("index");
+    }
+}

spring-web-modules/spring-web-url/src/main/java/com/baeldung/rootmapping/controller/RootController.java

@@ -0,0 +1,12 @@
+package com.baeldung.rootmapping.controller;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+
+@Controller
+public class RootController {
+    @GetMapping("/")
+    public String index() {
+        return "index";
+    }
+}