Merge branch 'master' into JAVA-2399-Update_spring-security-rest_module_to_use_Swagger_3.0.0

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

@@ -7,3 +7,4 @@ This module contains articles about Java 11 core features
 - [Guide to Java Reflection](http://www.baeldung.com/java-reflection)
 - [Guide to Java 8’s Collectors](https://www.baeldung.com/java-8-collectors)
 - [New Features in Java 11](https://www.baeldung.com/java-11-new-features)
+- [Getting the Java Version at Runtime](https://www.baeldung.com/get-java-version-runtime)

core-java-modules/core-java-9-jigsaw/pom.xml

@@ -34,4 +34,4 @@
         <maven.compiler.target>1.9</maven.compiler.target>
     </properties>
 
-</project>
+</project>

core-java-modules/core-java-9-streams/pom.xml

@@ -7,7 +7,7 @@
     <version>0.1.0-SNAPSHOT</version>
     <name>core-java-9-streams</name>
     <packaging>jar</packaging>
-    
+
     <parent>
         <groupId>com.baeldung.core-java-modules</groupId>
         <artifactId>core-java-modules</artifactId>
@@ -25,4 +25,4 @@
         </resources>
     </build>
 
-</project>
+</project>

core-java-modules/core-java-exceptions-3/src/main/java/com/baeldung/exceptions/illegalaccesserror/Class1.java

@@ -0,0 +1,8 @@
+package com.baeldung.exceptions.illegalaccesserror;
+
+public class Class1 {
+
+    public void bar() {
+        System.out.println("SUCCESS");
+    }
+}

core-java-modules/core-java-exceptions-3/src/main/java/com/baeldung/exceptions/illegalaccesserror/Class2.java

@@ -0,0 +1,10 @@
+package com.baeldung.exceptions.illegalaccesserror;
+
+public class Class2 {
+
+    public void foo() {
+        Class1 c1 = new Class1();
+        c1.bar();
+    }
+}
+    

core-java-modules/core-java-exceptions-3/src/main/java/com/baeldung/exceptions/illegalaccesserror/IllegalAccessErrorExample.java

@@ -0,0 +1,20 @@
+package com.baeldung.exceptions.illegalaccesserror;
+
+public class IllegalAccessErrorExample {
+
+    interface Baeldung {
+        public default void foobar() {
+            System.out.println("This is a default method.");
+        }
+    }
+
+    class Super {
+        private void foobar() {
+            System.out.println("SuperClass method foobar");
+        }
+    }
+
+    class MySubClass extends Super implements Baeldung {
+
+    }
+}

core-java-modules/core-java-exceptions-3/src/main/java/com/baeldung/exceptions/illegalaccesserror/IllegalAccessErrorSolved.java

@@ -0,0 +1,20 @@
+package com.baeldung.exceptions.illegalaccesserror;
+
+public class IllegalAccessErrorSolved {
+
+    interface BaeldungSolved {
+        public default void foobar() {
+            System.out.println("This is a default method.");
+        }
+    }
+
+    class SuperSolved {
+        public void foobar() {
+            System.out.println("SuperClass method foobar");
+        }
+    }
+
+    class MySubClassSolved extends SuperSolved implements BaeldungSolved {
+
+    }
+}

core-java-modules/core-java-exceptions-3/src/test/java/com/baeldung/exceptions/illegalaccesserror/IllegalAccessErrorExampleUnitTest.java

@@ -0,0 +1,21 @@
+package com.baeldung.exceptions.illegalaccesserror;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class IllegalAccessErrorExampleUnitTest {
+
+    @Test()
+    public void givenInterfaceDefaultMethOverriddenPrivateAccess_whenInvoked_thenIllegalAccessError() {
+        Assertions.assertThrows(IllegalAccessError.class, () -> {
+            new IllegalAccessErrorExample().new MySubClass().foobar();
+        });
+    }
+
+    @Test()
+    public void givenClass1Class2_whenSameClassDefintion_thenNoIllegalAccessError() {
+        Assertions.assertDoesNotThrow(() -> {
+            new Class2().foo();
+        });
+    }
+}

core-java-modules/core-java-exceptions-3/src/test/java/com/baeldung/exceptions/illegalaccesserror/IllegalAccessErrorSolvedUnitTest.java

@@ -0,0 +1,14 @@
+package com.baeldung.exceptions.illegalaccesserror;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class IllegalAccessErrorSolvedUnitTest {
+
+    @Test()
+    public void givenInterfaceDefaultMethOverriddenNonPrivateAccess_whenInvoked_thenNoIllegalAccessError() {
+        Assertions.assertDoesNotThrow(() -> {
+            new IllegalAccessErrorSolved().new MySubClassSolved().foobar();
+        });
+    }
+}

core-java-modules/core-java-io-4/src/main/java/com/baeldung/deserialization/vulnerabilities/BadThing.java

@@ -0,0 +1,28 @@
+package com.baeldung.deserialization.vulnerabilities;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.lang.reflect.Method;
+
+public class BadThing implements Serializable {
+    private static final long serialVersionUID = 0L;
+
+    Object looselyDefinedThing;
+    String methodName;
+
+    private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException {
+        ois.defaultReadObject();
+        try {
+            Method method = looselyDefinedThing.getClass().getMethod(methodName);
+            method.invoke(looselyDefinedThing);
+        } catch (Exception e) {
+            // handle error...
+        }
+    }
+
+    private void writeObject(ObjectOutputStream oos) throws IOException {
+        oos.defaultWriteObject();
+    }
+}

core-java-modules/core-java-io-4/src/main/java/com/baeldung/deserialization/vulnerabilities/MyCustomAttackObject.java

@@ -0,0 +1,14 @@
+package com.baeldung.deserialization.vulnerabilities;
+
+import java.io.IOException;
+import java.io.Serializable;
+
+public class MyCustomAttackObject implements Serializable {
+    public static void methodThatTriggersAttack() {
+        try {
+            Runtime.getRuntime().exec("echo \"Oh, no! I've been hacked\"");
+        } catch (IOException e) {
+            // handle error...
+        }
+    }
+}

core-java-modules/core-java-io-4/src/test/java/com/baeldung/deserialization/vulnerabilities/BadThingUnitTest.java

@@ -0,0 +1,40 @@
+package com.baeldung.deserialization.vulnerabilities;
+
+import org.junit.Test;
+import org.junit.jupiter.api.DisplayName;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+
+public class BadThingUnitTest {
+
+    @Test
+    @DisplayName("When a BadThing object is deserialized, then code execution in MyCustomAttackObject is run.")
+    public void givenABadThingObject_whenItsDeserialized_thenExecutionIsRun() throws Exception {
+        BadThing bt = new BadThing();
+
+        bt.looselyDefinedThing = new MyCustomAttackObject();
+        bt.methodName = "methodThatTriggersAttack";
+
+        byte[] serializedObject = serialize(bt);
+
+        try (InputStream bis = new ByteArrayInputStream(serializedObject);
+             ObjectInputStream ois = new ObjectInputStream(bis)) {
+
+            ois.readObject(); // malicious code is run
+        }
+    }
+
+    private static byte[] serialize(Object object) throws Exception {
+        try (ByteArrayOutputStream bos = new ByteArrayOutputStream();
+             ObjectOutputStream oos = new ObjectOutputStream(bos)) {
+
+            oos.writeObject(object);
+            oos.flush();
+            return bos.toByteArray();
+        }
+    }
+}

core-java-modules/core-java-jpms/decoupling-pattern2/consumermodule2/pom.xml

@@ -45,4 +45,4 @@
         <providermodule.version>1.0</providermodule.version>
     </properties>
 
-</project>
+</project>

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

@@ -5,3 +5,4 @@ This module contains articles about core features in the Java language
 - [The Java final Keyword – Impact on Performance](https://www.baeldung.com/java-final-performance)
 - [The package-info.java File](https://www.baeldung.com/java-package-info)
 - [What are Compile-time Constants in Java?](https://www.baeldung.com/java-compile-time-constants)
+- [Java Objects.hash() vs Objects.hashCode()](https://www.baeldung.com/java-objects-hash-vs-objects-hashcode)

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

@@ -7,3 +7,4 @@ This module contains articles about Object-oriented programming (OOP) patterns i
 - [Inheritance and Composition (Is-a vs Has-a relationship) in Java](https://www.baeldung.com/java-inheritance-composition)
 - [Immutable Objects in Java](https://www.baeldung.com/java-immutable-object)
 - [How to Make a Deep Copy of an Object in Java](https://www.baeldung.com/java-deep-copy)
+- [Using an Interface vs. Abstract Class in Java](https://www.baeldung.com/java-interface-vs-abstract-class)

core-java-modules/core-java-regex/src/test/java/com/baeldung/ignore/pattern/metacharacters/IgnoringPatternMetacharactersUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.ignore.pattern.metacharacters;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.junit.Test;
+
+public class IgnoringPatternMetacharactersUnitTest {
+    private static final String dollarAmounts = "$100.25, $100.50, $150.50, $100.50, $100.75";
+    private static final String patternStr = "$100.50";
+
+    @Test
+    public void givenPatternStringHasMetacharacters_whenPatternMatchedWithoutEscapingMetacharacters_thenNoMatchesFound() {
+        Pattern pattern = Pattern.compile(patternStr);
+        Matcher matcher = pattern.matcher(dollarAmounts);
+
+        int matches = 0;
+        while (matcher.find()) {
+            matches++;
+        }
+
+        assertEquals(0, matches);
+    }
+
+    @Test
+    public void givenPatternStringHasMetacharacters_whenPatternCompiledUsingManuallyMetaEscapedPattern_thenMatchingSuccessful() {
+        String metaEscapedPatternStr = "\\Q" + patternStr + "\\E";
+        Pattern pattern = Pattern.compile(metaEscapedPatternStr);
+        Matcher matcher = pattern.matcher(dollarAmounts);
+
+        int matches = 0;
+        while (matcher.find()) {
+            matches++;
+        }
+
+        assertEquals(2, matches);
+    }
+
+    @Test
+    public void givenPatternStringHasMetacharacters_whenPatternCompiledUsingLiteralPatternFromQuote_thenMatchingSuccessful() {
+        String literalPatternStr = Pattern.quote(patternStr);
+        Pattern pattern = Pattern.compile(literalPatternStr);
+        Matcher matcher = pattern.matcher(dollarAmounts);
+
+        int matches = 0;
+        while (matcher.find()) {
+            matches++;
+        }
+
+        assertEquals(2, matches);
+    }
+}

core-java-modules/core-java-security-2/src/main/java/com/baeldung/secretkeyandstringconversion/ConversionClassUtil.java

@@ -0,0 +1,53 @@
+package com.baeldung.secretkeyandstringconversion;
+
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.KeySpec;
+import java.util.Base64;
+
+import javax.crypto.KeyGenerator;
+import javax.crypto.SecretKey;
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+import javax.crypto.spec.SecretKeySpec;
+
+public class ConversionClassUtil {
+
+	/* Generating Secret key */
+
+	// Generating Secret Key using KeyGenerator class with 256
+	public static SecretKey generateKey(int n) throws NoSuchAlgorithmException {
+		KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
+		keyGenerator.init(n);
+		SecretKey originalKey = keyGenerator.generateKey();
+		return originalKey;
+	}
+
+	// Generating Secret Key using password and salt
+	public static SecretKey getKeyFromPassword(String password, String salt)
+			throws NoSuchAlgorithmException, InvalidKeySpecException {
+		SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
+		KeySpec spec = new PBEKeySpec(password.toCharArray(), salt.getBytes(), 65536, 256);
+		SecretKey originalKey = new SecretKeySpec(factory.generateSecret(spec).getEncoded(), "AES");
+		return originalKey;
+	}
+
+	/* Converting Secret key into String */
+	public static String convertSecretKeyToString(SecretKey secretKey) throws NoSuchAlgorithmException {
+		// Converting the Secret Key into byte array
+		byte[] rawData = secretKey.getEncoded();
+		// Getting String - Base64 encoded version of the Secret Key
+		String encodedKey = Base64.getEncoder().encodeToString(rawData);
+		return encodedKey;
+	}
+
+	/* Converting String into Secret key into */
+	public static SecretKey convertStringToSecretKeyto(String encodedKey) {
+		// Decoding the Base64 encoded string into byte array
+		byte[] decodedKey = Base64.getDecoder().decode(encodedKey);
+		// Rebuilding the Secret Key using SecretKeySpec Class
+		SecretKey originalKey = new SecretKeySpec(decodedKey, 0, decodedKey.length, "AES");
+		return originalKey;
+	}
+
+}

core-java-modules/core-java-security-2/src/test/java/com/baeldung/secretkeyandstringconversion/ConversionClassUtilUnitTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.secretkeyandstringconversion;
+
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+
+import javax.crypto.SecretKey;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class ConversionClassUtilUnitTest {
+
+	@Test
+	void givenPasswordAndSalt_whenCreateSecreKeyCheckConversion_thenSuccess()
+			throws NoSuchAlgorithmException, InvalidKeySpecException {
+		// given
+		String password = "Baeldung@2021";
+		String salt = "@$#baelDunG@#^$*";
+
+		// when
+		SecretKey encodedKey = ConversionClassUtil.getKeyFromPassword(password, salt);
+		String encodedString = ConversionClassUtil.convertSecretKeyToString(encodedKey);
+		SecretKey decodeKey = ConversionClassUtil.convertStringToSecretKeyto(encodedString);
+
+		// then
+		Assertions.assertEquals(encodedKey, decodeKey);
+	}
+
+	@Test
+	void givenSize_whenCreateSecreKeyCheckConversion_thenSuccess()
+			throws NoSuchAlgorithmException, InvalidKeySpecException {
+		// given
+		int size = 256;
+
+		// when
+		SecretKey encodedKey = ConversionClassUtil.generateKey(size);
+		String encodedString = ConversionClassUtil.convertSecretKeyToString(encodedKey);
+		SecretKey decodeKey = ConversionClassUtil.convertStringToSecretKeyto(encodedString);
+
+		// then
+		Assertions.assertEquals(encodedKey, decodeKey);
+	}
+
+}

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

@@ -12,4 +12,5 @@ This module contains articles about the Stream API in Java.
 - [Should We Close a Java Stream?](https://www.baeldung.com/java-stream-close)
 - [Returning Stream vs. Collection](https://www.baeldung.com/java-return-stream-collection)
 - [Convert a Java Enumeration Into a Stream](https://www.baeldung.com/java-enumeration-to-stream)
+- [When to Use a Parallel Stream in Java](https://www.baeldung.com/java-when-to-use-parallel-stream)
 - More articles: [[<-- prev>]](/../core-java-streams-2)

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

@@ -27,6 +27,17 @@
             <version>${lombok.version}</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${jmh.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${jmh.version}</version>
+            <scope>test</scope>
+        </dependency>
         <!-- test scoped -->
         <dependency>
             <groupId>org.assertj</groupId>
@@ -44,11 +55,30 @@
                 <filtering>true</filtering>
             </resource>
         </resources>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                    <annotationProcessorPaths>
+                        <path>
+                            <groupId>org.openjdk.jmh</groupId>
+                            <artifactId>jmh-generator-annprocess</artifactId>
+                            <version>${jmh.version}</version>
+                        </path>
+                    </annotationProcessorPaths>
+                </configuration>
+            </plugin>
+        </plugins>
     </build>
 
     <properties>
+        <lombok.version>1.18.20</lombok.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
+        <jmh.version>1.29</jmh.version>
     </properties>
 
 </project>

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/BenchmarkRunner.java

@@ -0,0 +1,9 @@
+package com.baeldung.streams.parallel;
+
+public class BenchmarkRunner {
+
+    public static void main(String[] args) throws Exception {
+        org.openjdk.jmh.Main.main(args);
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/DifferentSourceSplitting.java

@@ -0,0 +1,54 @@
+package com.baeldung.streams.parallel;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.IntStream;
+
+public class DifferentSourceSplitting {
+
+    private static final List<Integer> arrayListOfNumbers = new ArrayList<>();
+    private static final List<Integer> linkedListOfNumbers = new LinkedList<>();
+
+    static {
+        IntStream.rangeClosed(1, 1_000_000).forEach(i -> {
+            arrayListOfNumbers.add(i);
+            linkedListOfNumbers.add(i);
+        });
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void differentSourceArrayListSequential() {
+        arrayListOfNumbers.stream().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void differentSourceArrayListParallel() {
+        arrayListOfNumbers.parallelStream().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void differentSourceLinkedListSequential() {
+        linkedListOfNumbers.stream().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void differentSourceLinkedListParallel() {
+        linkedListOfNumbers.parallelStream().reduce(0, Integer::sum);
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/MemoryLocalityCosts.java

@@ -0,0 +1,52 @@
+package com.baeldung.streams.parallel;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+
+import java.util.Arrays;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.IntStream;
+
+public class MemoryLocalityCosts {
+
+    private static final int[] intArray = new int[1_000_000];
+    private static final Integer[] integerArray = new Integer[1_000_000];
+
+    static {
+        IntStream.rangeClosed(1, 1_000_000).forEach(i -> {
+            intArray[i-1] = i;
+            integerArray[i-1] = i;
+        });
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void localityIntArraySequential() {
+        Arrays.stream(intArray).reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void localityIntArrayParallel() {
+        Arrays.stream(intArray).parallel().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void localityIntegerArraySequential() {
+        Arrays.stream(integerArray).reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void localityIntegerArrayParallel() {
+        Arrays.stream(integerArray).parallel().reduce(0, Integer::sum);
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/MergingCosts.java

@@ -0,0 +1,52 @@
+package com.baeldung.streams.parallel;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class MergingCosts {
+
+    private static final List<Integer> arrayListOfNumbers = new ArrayList<>();
+
+    static {
+        IntStream.rangeClosed(1, 1_000_000).forEach(i -> {
+            arrayListOfNumbers.add(i);
+        });
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void mergingCostsSumSequential() {
+        arrayListOfNumbers.stream().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void mergingCostsSumParallel() {
+        arrayListOfNumbers.stream().parallel().reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void mergingCostsGroupingSequential() {
+        arrayListOfNumbers.stream().collect(Collectors.toSet());
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void mergingCostsGroupingParallel() {
+        arrayListOfNumbers.stream().parallel().collect(Collectors.toSet());
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/ParallelStream.java

@@ -0,0 +1,15 @@
+package com.baeldung.streams.parallel;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class ParallelStream {
+
+    public static void main(String[] args) {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        listOfNumbers.parallelStream().forEach(number ->
+          System.out.println(number + " " + Thread.currentThread().getName())
+        );
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/SequentialStream.java

@@ -0,0 +1,15 @@
+package com.baeldung.streams.parallel;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class SequentialStream {
+
+    public static void main(String[] args) {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        listOfNumbers.stream().forEach(number ->
+          System.out.println(number + " " + Thread.currentThread().getName())
+        );
+    }
+
+}

core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/SplittingCosts.java

@@ -0,0 +1,27 @@
+package com.baeldung.streams.parallel;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+
+import java.util.concurrent.TimeUnit;
+import java.util.stream.IntStream;
+
+public class SplittingCosts {
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void sourceSplittingIntStreamSequential() {
+        IntStream.rangeClosed(1, 100).reduce(0, Integer::sum);
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    public static void sourceSplittingIntStreamParallel() {
+        IntStream.rangeClosed(1, 100).parallel().reduce(0, Integer::sum);
+    }
+
+}

core-java-modules/core-java-streams-3/src/test/java/com/baeldung/streams/parallel/ForkJoinUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.streams.parallel;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ForkJoinPool;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ForkJoinUnitTest {
+
+    @Test
+    void givenSequentialStreamOfNumbers_whenReducingSumWithIdentityFive_thenResultIsCorrect() {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        int sum = listOfNumbers.stream().reduce(5, Integer::sum);
+        assertThat(sum).isEqualTo(15);
+    }
+
+    @Test
+    void givenParallelStreamOfNumbers_whenReducingSumWithIdentityFive_thenResultIsNotCorrect() {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        int sum = listOfNumbers.parallelStream().reduce(5, Integer::sum);
+        assertThat(sum).isNotEqualTo(15);
+    }
+
+    @Test
+    void givenParallelStreamOfNumbers_whenReducingSumWithIdentityZero_thenResultIsCorrect() {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        int sum = listOfNumbers.parallelStream().reduce(0, Integer::sum) + 5;
+        assertThat(sum).isEqualTo(15);
+    }
+
+    @Test
+    public void givenParallelStreamOfNumbers_whenUsingCustomThreadPool_thenResultIsCorrect()
+      throws InterruptedException, ExecutionException {
+        List<Integer> listOfNumbers = Arrays.asList(1, 2, 3, 4);
+        ForkJoinPool customThreadPool = new ForkJoinPool(4);
+        int sum = customThreadPool.submit(
+          () -> listOfNumbers.parallelStream().reduce(0, Integer::sum)).get();
+        customThreadPool.shutdown();
+        assertThat(sum).isEqualTo(10);
+    }
+
+}

core-java-modules/core-java-string-conversions-2/README.md

@@ -6,4 +6,5 @@ This module contains articles about string conversions from/to another type.
 - [Java String Conversions](https://www.baeldung.com/java-string-conversions)
 - [Convert String to Byte Array and Reverse in Java](https://www.baeldung.com/java-string-to-byte-array)
 - [Convert Character Array to String in Java](https://www.baeldung.com/java-char-array-to-string)
+- [Converting String to BigDecimal in Java](https://www.baeldung.com/java-string-to-bigdecimal)
 - More articles: [[<-- prev]](/core-java-string-conversions)

core-java-modules/core-java-string-conversions-2/src/test/java/com/baeldung/stringtobigdecimal/StringToBigDecimalConversionUnitTest.java

@@ -0,0 +1,74 @@
+package com.baeldung.stringtobigdecimal;
+
+import static org.junit.Assert.assertEquals;
+
+import java.math.BigDecimal;
+import java.text.DecimalFormat;
+import java.text.DecimalFormatSymbols;
+import java.text.ParseException;
+
+import org.junit.Test;
+
+public class StringToBigDecimalConversionUnitTest {
+
+	@Test
+	public void givenValidString_WhenBigDecimalObjectWithStringParameter_ThenResultIsDecimalObject() {
+		BigDecimal bigDecimal = new BigDecimal("123");
+		assertEquals(new BigDecimal(123), bigDecimal);
+	}
+
+	@Test(expected = NullPointerException.class)
+	public void givenNullString_WhenBigDecimalObjectWithStringParameter_ThenNullPointerExceptionIsThrown() {
+		String bigDecimal = null;
+		new BigDecimal(bigDecimal);
+	}
+
+	@Test(expected = NumberFormatException.class)
+	public void givenInalidString_WhenBigDecimalObjectWithStringParameter_ThenNumberFormatExceptionIsThrown() {
+		new BigDecimal("&");
+	}
+
+	@Test
+	public void givenValidString_WhenValueOfDoubleFromString_ThenResultIsDecimalObject() {
+		BigDecimal bigDecimal = BigDecimal.valueOf(Double.valueOf("123.42"));
+		assertEquals(new BigDecimal(123.42).setScale(2, BigDecimal.ROUND_HALF_UP), bigDecimal);
+	}
+
+	@Test(expected = NullPointerException.class)
+	public void givenNullString_WhenValueOfDoubleFromString_ThenNullPointerExceptionIsThrown() {
+		BigDecimal.valueOf(Double.valueOf(null));
+	}
+
+	@Test(expected = NumberFormatException.class)
+	public void givenInalidString_WhenValueOfDoubleFromString_ThenNumberFormatExceptionIsThrown() {
+		BigDecimal.valueOf(Double.valueOf("&"));
+	}
+
+	@Test
+	public void givenValidString_WhenDecimalFormatOfString_ThenResultIsDecimalObject() throws ParseException {
+		BigDecimal bigDecimal = new BigDecimal(10692467440017.111).setScale(3, BigDecimal.ROUND_HALF_UP);
+
+		DecimalFormatSymbols symbols = new DecimalFormatSymbols();
+		symbols.setGroupingSeparator(',');
+		symbols.setDecimalSeparator('.');
+		String pattern = "#,##0.0#";
+		DecimalFormat decimalFormat = new DecimalFormat(pattern, symbols);
+		decimalFormat.setParseBigDecimal(true);
+
+		// parse the string value
+		BigDecimal parsedStringValue = (BigDecimal) decimalFormat.parse("10,692,467,440,017.111");
+
+		assertEquals(bigDecimal, parsedStringValue);
+	}
+
+	@Test(expected = NullPointerException.class)
+	public void givenNullString_WhenDecimalFormatOfString_ThenNullPointerExceptionIsThrown() throws ParseException {
+		new DecimalFormat("#").parse(null);
+	}
+
+	@Test(expected = ParseException.class)
+	public void givenInalidString_WhenDecimalFormatOfString_ThenNumberFormatExceptionIsThrown() throws ParseException {
+		new DecimalFormat("#").parse("&");
+	}
+
+}

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

@@ -3,3 +3,4 @@
 - [Version Comparison in Java](https://www.baeldung.com/java-comparing-versions)
 - [Java (String) or .toString()?](https://www.baeldung.com/java-string-casting-vs-tostring)
 - [Split Java String by Newline](https://www.baeldung.com/java-string-split-by-newline)
+- [Split a String in Java and Keep the Delimiters](https://www.baeldung.com/java-split-string-keep-delimiters)

core-java-modules/core-java-string-operations-3/src/test/java/com/baeldung/splitkeepdelimiters/SplitAndKeepDelimitersUnitTest.java

@@ -0,0 +1,59 @@
+package com.baeldung.splitkeepdelimiters;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.regex.Pattern;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.jupiter.api.Test;
+
+import com.google.common.base.Splitter;
+
+public class SplitAndKeepDelimitersUnitTest {
+
+    private final String positivelookAheadRegex = "((?=@))";
+    private final String positivelookBehindRegex = "((?<=@))";
+    private final String positivelookAroundRegex = "((?=@)|(?<=@))";
+    private final String positiveLookAroundMultiDelimiterRegex = "((?=:|#|@)|(?<=:|#|@))";
+
+    private String text = "Hello@World@This@Is@A@Java@Program";
+    private String textMixed = "@HelloWorld@This:Is@A#Java#Program";
+    private String textMixed2 = "pg@no;10@hello;world@this;is@a#10words;Java#Program";
+
+    @Test
+    public void givenString_splitAndKeepDelimiters_using_javaLangString() {
+
+        assertThat(text.split(positivelookAheadRegex)).containsExactly("Hello", "@World", "@This", "@Is", "@A", "@Java", "@Program");
+
+        assertThat(text.split(positivelookBehindRegex)).containsExactly("Hello@", "World@", "This@", "Is@", "A@", "Java@", "Program");
+
+        assertThat(text.split(positivelookAroundRegex)).containsExactly("Hello", "@", "World", "@", "This", "@", "Is", "@", "A", "@", "Java", "@", "Program");
+
+        assertThat(textMixed.split(positiveLookAroundMultiDelimiterRegex)).containsExactly("@", "HelloWorld", "@", "This", ":", "Is", "@", "A", "#", "Java", "#", "Program");
+
+    }
+
+    @Test
+    public void givenString_splitAndKeepDelimiters_using_ApacheCommonsLang3StringUtils() {
+
+        assertThat(StringUtils.splitByCharacterType(textMixed2)).containsExactly("pg", "@", "no", ";", "10", "@", "hello", ";", "world", "@", "this", ";", "is", "@", "a", "#", "10", "words", ";", "J", "ava", "#", "P", "rogram");
+
+    }
+
+    @Test
+    public void givenString_splitAndKeepDelimiters_using_GuavaSplitter() {
+
+        assertThat(Splitter.onPattern(positivelookAroundRegex)
+            .splitToList(text)).containsExactly("Hello", "@", "World", "@", "This", "@", "Is", "@", "A", "@", "Java", "@", "Program");
+
+        assertThat(Splitter.on(Pattern.compile(positivelookAroundRegex))
+            .splitToList(text)).containsExactly("Hello", "@", "World", "@", "This", "@", "Is", "@", "A", "@", "Java", "@", "Program");
+
+        assertThat(Splitter.onPattern(positiveLookAroundMultiDelimiterRegex)
+            .splitToList(textMixed)).containsExactly("@", "HelloWorld", "@", "This", ":", "Is", "@", "A", "#", "Java", "#", "Program");
+
+        assertThat(Splitter.on(Pattern.compile(positiveLookAroundMultiDelimiterRegex))
+            .splitToList(textMixed)).containsExactly("@", "HelloWorld", "@", "This", ":", "Is", "@", "A", "#", "Java", "#", "Program");
+
+    }
+}

jws/pom.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<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/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.example</groupId>
     <artifactId>jws</artifactId>
@@ -66,4 +67,4 @@
         <maven-jar-plugin.version>3.0.2</maven-jar-plugin.version>
     </properties>
 
-</project>
+</project>

libraries-4/pom.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">    
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <artifactId>libraries-4</artifactId>
 

libraries-5/pom.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">    
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <artifactId>libraries-5</artifactId>
 

libraries-6/pom.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">    
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <artifactId>libraries-6</artifactId>
 
@@ -112,12 +112,12 @@
             <artifactId>renjin-script-engine</artifactId>
             <version>${renjin.version}</version>
         </dependency>
-        <!-- libphonenumber  -->
+        <!-- libphonenumber -->
         <dependency>
             <groupId>com.googlecode.libphonenumber</groupId>
             <artifactId>libphonenumber</artifactId>
             <version>${libphonenumber.version}</version>
-        </dependency>        
+        </dependency>
     </dependencies>
 
     <repositories>

libraries-http-2/src/main/java/com/baeldung/okhttp/interceptors/ErrorResponseInterceptor.java

@@ -21,7 +21,12 @@ public class ErrorResponseInterceptor implements Interceptor {
             Gson gson = new Gson();
             String body = gson.toJson(new ErrorMessage(response.code(), "The response from the server was not OK"));
             ResponseBody responseBody = ResponseBody.create(body, APPLICATION_JSON);
-            
+
+            ResponseBody originalBody = response.body();
+            if (originalBody != null) {
+                originalBody.close();
+            }
+
             return response.newBuilder()
                 .body(responseBody)
                 .build();

libraries/pom.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <artifactId>libraries</artifactId>
     <name>libraries</name>
@@ -335,7 +336,8 @@
                         <configuration>
                             <finalName>benchmarks</finalName>
                             <transformers>
-                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                <transformer
+                                    implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                     <mainClass>org.openjdk.jmh.Main</mainClass>
                                 </transformer>
                             </transformers>

lombok/pom.xml

@@ -73,8 +73,6 @@
     </build>
 
     <properties>
-        <!-- lombok: https://projectlombok.org/changelog.html -->
-        <lombok.version>1.18.10</lombok.version>
         <!-- various -->
         <hibernate-jpa-2.1-api.version>1.0.0.Final</hibernate-jpa-2.1-api.version>
         <!-- delombok maven plugin -->

mapstruct/src/main/java/com/baeldung/mapper/SimpleDestinationMapperUsingInjectedService.java

@@ -0,0 +1,22 @@
+package com.baeldung.mapper;
+
+import com.baeldung.dto.SimpleSource;
+import com.baeldung.entity.SimpleDestination;
+import com.baeldung.service.SimpleService;
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.springframework.beans.factory.annotation.Autowired;
+
+@Mapper(componentModel = "spring")
+public abstract class SimpleDestinationMapperUsingInjectedService {
+
+    @Autowired
+    protected SimpleService simpleService;
+
+    @Mapping(target = "name", expression = "java(simpleService.enrichName(source.getName()))")
+    public abstract SimpleDestination sourceToDestination(SimpleSource source);
+
+    public abstract SimpleSource destinationToSource(SimpleDestination destination);
+
+
+}

mapstruct/src/main/java/com/baeldung/service/SimpleService.java

@@ -0,0 +1,11 @@
+package com.baeldung.service;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public class SimpleService {
+
+    public String enrichName(String name) {
+        return "-:: " + name + " ::-";
+    }
+}

mapstruct/src/test/java/com/baeldung/mapper/SimpleDestinationMapperUsingInjectedIntegrationTest.java

@@ -0,0 +1,35 @@
+package com.baeldung.mapper;
+
+import com.baeldung.dto.SimpleSource;
+import com.baeldung.entity.SimpleDestination;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration("classpath:applicationContext.xml")
+public class SimpleDestinationMapperUsingInjectedIntegrationTest {
+
+    @Autowired
+    private SimpleDestinationMapperUsingInjectedService mapper;
+
+    @Test
+    public void givenSourceToDestination_whenMaps_thenNameEnriched() {
+        // Given
+        SimpleSource source = new SimpleSource();
+        source.setName("Bob");
+        source.setDescription("The Builder");
+
+        // When
+        SimpleDestination destination = mapper.sourceToDestination(source);
+
+        // Then
+        assertThat(destination).isNotNull();
+        assertThat(destination.getName()).isEqualTo("-:: Bob ::-");
+        assertThat(destination.getDescription()).isEqualTo("The Builder");
+    }
+}

maven-modules/maven-copy-files/README.md

@@ -0,0 +1,3 @@
+### Relevant Articles:
+
+- [Copying Files With Maven](https://www.baeldung.com/maven-copy-files)

maven-modules/maven-printing-plugins/README.md

@@ -0,0 +1,7 @@
+## Maven Printing Plugins
+
+This module contains articles about printing from Maven plugins.
+
+### Relevant Articles
+
+- [How to Display a Message in Maven](https://www.baeldung.com/maven-print-message-during-execution)

maven-modules/maven-printing-plugins/pom.xml

@@ -49,9 +49,11 @@
                             <goal>echo</goal>
                         </goals>
                         <configuration>
-                            <message>Hello, world</message>
-                            <message>Embed a line break: ${line.separator}</message>
-                            <message>ArtifactId is ${project.artifactId}</message>
+                            <message>
+                                Hello, world
+                                Embed a line break: ${line.separator}
+                                ArtifactId is ${project.artifactId}
+                            </message>
                             <level>INFO</level>
                             <toFile>/logs/log-echo.txt</toFile>
                             <append>true</append>

netflix-modules/mantis/pom.xml

@@ -19,7 +19,6 @@
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter</artifactId>
-            <version>2.1.3.RELEASE</version>
         </dependency>
         <dependency>
             <groupId>io.mantisrx</groupId>
@@ -35,36 +34,31 @@
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
-            <version>2.10.2</version>
         </dependency>
         <dependency>
             <groupId>net.andreinc.mockneat</groupId>
             <artifactId>mockneat</artifactId>
-            <version>0.3.8</version>
+            <version>0.4.2</version>
         </dependency>
         <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
-            <version>1.18.12</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-webflux</artifactId>
-            <version>5.0.9.RELEASE</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>io.projectreactor.netty</groupId>
             <artifactId>reactor-netty</artifactId>
-            <version>0.9.12.RELEASE</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
-
     <repositories>
         <repository>
-            <id>SpringLibReleaseRepo</id>
-            <url>https://repo.spring.io/libs-release/</url>
+        	<id>jcenter</id>
+            <url>https://jcenter.bintray.com/</url>
         </repository>
     </repositories>
 

patterns/design-patterns-behavioral/pom.xml

@@ -26,6 +26,11 @@
             <version>${lombok.version}</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.code.findbugs</groupId>
+            <artifactId>annotations</artifactId>
+            <version>${findbugs.annotations.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
@@ -41,6 +46,7 @@
 
     <properties>
         <intellij.annotations.version>16.0.2</intellij.annotations.version>
+        <findbugs.annotations.version>3.0.1</findbugs.annotations.version>
         <assertj-core.version>3.9.1</assertj-core.version>
     </properties>
 

patterns/design-patterns-behavioral/src/main/java/com/baeldung/nulls/FindBugsAnnotations.java

@@ -1,12 +1,12 @@
 package com.baeldung.nulls;
 
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
+import edu.umd.cs.findbugs.annotations.NonNull;
+import edu.umd.cs.findbugs.annotations.Nullable;
 
 public class FindBugsAnnotations {
 
-    public void accept(@NotNull Object param) {
+    public void accept(@NonNull Object param) {
         System.out.println(param.toString());
     }
 
@@ -14,7 +14,7 @@ public class FindBugsAnnotations {
         System.out.println("Printing " + param);
     }
 
-    @NotNull
+    @NonNull
     public Object process() throws Exception {
         Object result = doSomething();
         if (result == null) {

persistence-modules/java-jpa-3/README.md

@@ -10,3 +10,4 @@ This module contains articles about the Java Persistence API (JPA) in Java.
 - [JPA CascadeType.REMOVE vs orphanRemoval](https://www.baeldung.com/jpa-cascade-remove-vs-orphanremoval)
 - [A Guide to MultipleBagFetchException in Hibernate](https://www.baeldung.com/java-hibernate-multiplebagfetchexception)
 - [How to Convert a Hibernate Proxy to a Real Entity Object](https://www.baeldung.com/hibernate-proxy-to-real-entity-object)
+- [Returning an Auto-Generated Id with JPA](https://www.baeldung.com/jpa-get-auto-generated-id)

persistence-modules/java-jpa-3/pom.xml

@@ -68,6 +68,12 @@
             <version>${assertj.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

persistence-modules/java-jpa-3/src/main/java/com/baeldung/jpa/IdGeneration/User.java

@@ -0,0 +1,41 @@
+package com.baeldung.jpa.IdGeneration;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class User {
+
+    @Id
+//    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private long id;
+    private String username;
+    private String password;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+}

persistence-modules/java-jpa-3/src/main/java/com/baeldung/jpa/IdGeneration/UserService.java

@@ -0,0 +1,19 @@
+package com.baeldung.jpa.IdGeneration;
+
+import javax.persistence.EntityManager;
+import javax.transaction.Transactional;
+
+public class UserService {
+
+    EntityManager entityManager;
+
+    public UserService(EntityManager entityManager) {
+        this.entityManager = entityManager;
+    }
+
+    @Transactional
+    public long saveUser(User user){
+        entityManager.persist(user);
+        return user.getId();
+    }
+}

persistence-modules/java-jpa-3/src/main/resources/META-INF/persistence.xml

@@ -97,4 +97,20 @@
             <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false"/>
         </properties>
     </persistence-unit>
+
+    <persistence-unit name="jpa-h2-id-generation">
+        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+        <class>com.baeldung.jpa.IdGeneration.User</class>
+        <exclude-unlisted-classes>true</exclude-unlisted-classes>
+        <properties>
+            <property name="javax.persistence.jdbc.driver" value="org.h2.Driver"/>
+            <property name="javax.persistence.jdbc.url" value="jdbc:h2:mem:idGen"/>
+            <property name="javax.persistence.jdbc.user" value="sa"/>
+            <property name="javax.persistence.jdbc.password" value=""/>
+            <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>
+            <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
+            <property name="hibernate.format_sql" value="true"/>
+            <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false"/>
+        </properties>
+    </persistence-unit>
 </persistence>

persistence-modules/java-jpa-3/src/test/java/com/baeldung/jpa/IdGeneration/IdGenerationIntegrationTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.jpa.IdGeneration;
+
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+import java.util.UUID;
+
+public class IdGenerationIntegrationTest {
+
+    private static EntityManager entityManager;
+    private static UserService service;
+
+    @BeforeClass
+    public static void setup() {
+        EntityManagerFactory factory = Persistence.createEntityManagerFactory("jpa-h2-id-generation");
+        entityManager = factory.createEntityManager();
+        service = new UserService(entityManager);
+    }
+
+    @Test
+    public void whenNewUserIsPersisted_thenEntityHasNoId() {
+        User user = new User();
+        user.setUsername("test");
+        user.setPassword(UUID.randomUUID().toString());
+
+        long index = service.saveUser(user);
+        Assert.assertEquals(0L, index);
+    }
+
+    @Test
+    public void whenTransactionIsControlled_thenEntityHasId() {
+        User user = new User();
+        user.setUsername("test");
+        user.setPassword(UUID.randomUUID().toString());
+
+        entityManager.getTransaction().begin();
+        long index = service.saveUser(user);
+        entityManager.getTransaction().commit();
+
+        Assert.assertEquals(2L, index);
+    }
+
+}

persistence-modules/spring-data-jpa-annotations/README.md

@@ -9,6 +9,7 @@ This module contains articles about annotations used in Spring Data JPA
 - [Spring JPA @Embedded and @EmbeddedId](https://www.baeldung.com/spring-jpa-embedded-method-parameters)
 - [Programmatic Transaction Management in Spring](https://www.baeldung.com/spring-programmatic-transaction-management)
 - [JPA Entity Lifecycle Events](https://www.baeldung.com/jpa-entity-lifecycle-events)
+- [Overriding Column Definition With @AttributeOverride](https://www.baeldung.com/jpa-attributeoverride)
 
 ### Eclipse Config 
 After importing the project into Eclipse, you may see the following error:  

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Address.java

@@ -0,0 +1,25 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.Embeddable;
+
+@Embeddable
+public class Address {
+    private String name;
+    private String city;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getCity() {
+        return city;
+    }
+
+    public void setCity(String city) {
+        this.city = city;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Brand.java

@@ -0,0 +1,29 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.Embeddable;
+import javax.persistence.Embedded;
+import java.time.LocalDate;
+
+@Embeddable
+public class Brand {
+    private String name;
+    private LocalDate foundationDate;
+    @Embedded
+    private Address address;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public LocalDate getFoundationDate() {
+        return foundationDate;
+    }
+
+    public void setFoundationDate(LocalDate foundationDate) {
+        this.foundationDate = foundationDate;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Car.java

@@ -0,0 +1,54 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.AttributeOverride;
+import javax.persistence.AttributeOverrides;
+import javax.persistence.Column;
+import javax.persistence.ElementCollection;
+import javax.persistence.Embedded;
+import javax.persistence.Entity;
+import java.util.Map;
+
+@Entity
+@AttributeOverride(name = "identifier", column = @Column(name = "VIN"))
+public class Car extends Vehicle {
+
+    private String model;
+    private String name;
+    @Embedded
+    @AttributeOverrides({
+      @AttributeOverride(name = "name", column = @Column(name = "BRAND_NAME", length = 5)),
+      @AttributeOverride(name = "address.name", column = @Column(name = "ADDRESS_NAME"))
+    })
+    private Brand brand;
+    @ElementCollection
+    @AttributeOverrides({
+      @AttributeOverride(name = "key.name", column = @Column(name = "OWNER_NAME")),
+      @AttributeOverride(name = "key.surname", column = @Column(name = "OWNER_SURNAME")),
+      @AttributeOverride(name = "value.name", column = @Column(name = "ADDRESS_NAME")),
+    })
+    Map<Owner, Address> owners;
+
+    public String getModel() {
+        return model;
+    }
+
+    public void setModel(String model) {
+        this.model = model;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Brand getBrand() {
+        return brand;
+    }
+
+    public void setBrand(Brand brand) {
+        this.brand = brand;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Owner.java

@@ -0,0 +1,25 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.Embeddable;
+
+@Embeddable
+public class Owner {
+    private String name;
+    private String surname;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/entity/Vehicle.java

@@ -0,0 +1,38 @@
+package com.baeldung.attribute.override.entity;
+
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.MappedSuperclass;
+
+@MappedSuperclass
+public class Vehicle {
+    @Id
+    @GeneratedValue
+    private Integer id;
+    private String identifier;
+    private Integer numberOfWheels;
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public String getIdentifier() {
+        return identifier;
+    }
+
+    public void setIdentifier(String identifier) {
+        this.identifier = identifier;
+    }
+
+    public Integer getNumberOfWheels() {
+        return numberOfWheels;
+    }
+
+    public void setNumberOfWheels(Integer numberOfWheels) {
+        this.numberOfWheels = numberOfWheels;
+    }
+}

persistence-modules/spring-data-jpa-annotations/src/main/java/com/baeldung/attribute/override/repository/CarRepository.java

@@ -0,0 +1,7 @@
+package com.baeldung.attribute.override.repository;
+
+import com.baeldung.attribute.override.entity.Car;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface CarRepository extends JpaRepository<Car, Integer> {
+}

persistence-modules/spring-data-jpa-annotations/src/test/java/com/baeldung/attribute/override/AttributeOverrideIntegrationTest.java

@@ -0,0 +1,56 @@
+package com.baeldung.attribute.override;
+
+import com.baeldung.Application;
+import com.baeldung.attribute.override.entity.Address;
+import com.baeldung.attribute.override.entity.Brand;
+import com.baeldung.attribute.override.entity.Car;
+import com.baeldung.attribute.override.repository.CarRepository;
+import org.assertj.core.api.Assertions;
+import org.jetbrains.annotations.NotNull;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.LocalDate;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = { Application.class })
+public class AttributeOverrideIntegrationTest {
+
+    private static final LocalDate FORD_FOUNDATION_DATE = LocalDate.parse("1903-06-16");
+    @Autowired
+    CarRepository carRepository;
+
+    @Test
+    @Transactional
+    public void whenInsertingCar_thenEmbeddedAndMappedFieldsArePopulated() {
+
+        Car fordMustang = createMustang();
+
+        carRepository.save(fordMustang);
+        Car actualCar = carRepository.getOne(fordMustang.getId());
+
+        Assertions.assertThat(actualCar).isEqualTo(fordMustang);
+    }
+
+    @NotNull
+    private Car createMustang() {
+        Address address = new Address();
+        address.setName("Ford United States");
+        address.setCity("Dearborn");
+
+        Brand ford = new Brand();
+        ford.setName("Ford");
+        ford.setFoundationDate(FORD_FOUNDATION_DATE);
+
+        Car fordMustang = new Car();
+        fordMustang.setIdentifier("WP1AB29P88LA47599");
+        fordMustang.setModel("Ford");
+        fordMustang.setName("My car");
+        fordMustang.setBrand(ford);
+        return fordMustang;
+    }
+}

persistence-modules/spring-data-jpa-crud/README.md

@@ -10,6 +10,7 @@ This module contains articles about CRUD operations in Spring Data JPA
 - [Batch Insert/Update with Hibernate/JPA](https://www.baeldung.com/jpa-hibernate-batch-insert-update)
 - [Difference Between save() and saveAndFlush() in Spring Data JPA](https://www.baeldung.com/spring-data-jpa-save-saveandflush)
 - [Generate Database Schema with Spring Data JPA](https://www.baeldung.com/spring-data-jpa-generate-db-schema)
+- [How to Implement a Soft Delete with Spring JPA](https://www.baeldung.com/spring-jpa-soft-delete)
 
 ### Eclipse Config 
 After importing the project into Eclipse, you may see the following error:  

persistence-modules/spring-data-jpa-crud/src/main/java/com/baeldung/softdelete/Product.java

@@ -0,0 +1,68 @@
+package com.baeldung.softdelete;
+
+
+import java.io.Serializable;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+import org.hibernate.annotations.Filter;
+import org.hibernate.annotations.FilterDef;
+import org.hibernate.annotations.ParamDef;
+import org.hibernate.annotations.SQLDelete;
+
+@Entity
+@Table(name = "tbl_products")
+@SQLDelete(sql = "UPDATE tbl_products SET deleted = true WHERE id=?")
+@FilterDef(name = "deletedProductFilter", parameters = @ParamDef(name = "isDeleted", type = "boolean"))
+@Filter(name = "deletedProductFilter", condition = "deleted = :isDeleted")
+public class Product implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String name;
+
+    private double price;
+
+    private boolean deleted = Boolean.FALSE;
+
+    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 double getPrice() {
+        return price;
+    }
+
+    public void setPrice(double price) {
+        this.price = price;
+    }
+
+    public boolean isDeleted() {
+        return deleted;
+    }
+
+    public void setDeleted(boolean deleted) {
+        this.deleted = deleted;
+    }
+
+}

persistence-modules/spring-data-jpa-crud/src/main/java/com/baeldung/softdelete/ProductController.java

@@ -0,0 +1,34 @@
+package com.baeldung.softdelete;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/api/products")
+public class ProductController {
+
+    @Autowired
+    private ProductService productService;
+
+    @PostMapping
+    public Product createOne(@RequestBody Product product) {
+        return productService.create(product);
+    }
+
+    @DeleteMapping("/{id}")
+    public void removeOne(@PathVariable("id") Long id) {
+        productService.remove(id);
+    }
+
+    @GetMapping
+    public Iterable<Product> findAll(@RequestParam(value = "isDeleted", required = false, defaultValue = "false") boolean isDeleted) {
+        return productService.findAll(isDeleted);
+    }
+}

persistence-modules/spring-data-jpa-crud/src/main/java/com/baeldung/softdelete/ProductRepository.java

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

persistence-modules/spring-data-jpa-crud/src/main/java/com/baeldung/softdelete/ProductService.java

@@ -0,0 +1,35 @@
+package com.baeldung.softdelete;
+
+import javax.persistence.EntityManager;
+
+import org.hibernate.Filter;
+import org.hibernate.Session;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+@Service
+public class ProductService {
+
+    @Autowired
+    private ProductRepository productRepository;
+
+    @Autowired
+    private EntityManager entityManager;
+
+    public Product create(Product product) {
+        return productRepository.save(product);
+    }
+
+    public void remove(Long id){
+        productRepository.deleteById(id);
+    }
+
+    public Iterable<Product> findAll(boolean isDeleted){
+        Session session = entityManager.unwrap(Session.class);
+        Filter filter = session.enableFilter("deletedProductFilter");
+        filter.setParameter("isDeleted", isDeleted);
+        Iterable<Product> products =  productRepository.findAll();
+        session.disableFilter("deletedProductFilter");
+        return products;
+    }
+}

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

@@ -5,10 +5,5 @@ spring.jpa.properties.hibernate.order_inserts=true
 spring.jpa.properties.hibernate.order_updates=true
 spring.jpa.properties.hibernate.generate_statistics=true
 
-# JPA-Schema-Generation
-# Use below configuration to generate database schema create commands based on the entity models
-# and export them into the create.sql file
-#spring.jpa.properties.javax.persistence.schema-generation.scripts.action=create
-#spring.jpa.properties.javax.persistence.schema-generation.scripts.create-target=create.sql
-#spring.jpa.properties.javax.persistence.schema-generation.scripts.create-source=metadata
-#spring.jpa.properties.hibernate.format_sql=true
+spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
+

pom.xml

@@ -1276,6 +1276,7 @@
             </build>
 
             <modules>
+                 <module>spring-boot-modules/spring-boot-cassandre</module>
                  <module>core-java-modules/core-java-9</module>
                  <module>core-java-modules/core-java-9-improvements</module>
                  <module>core-java-modules/core-java-9-jigsaw</module>
@@ -1404,7 +1405,7 @@
         <maven-jxr-plugin.version>3.0.0</maven-jxr-plugin.version>
         <!-- <maven-pmd-plugin.version>3.9.0</maven-pmd-plugin.version> -->
         <maven-pmd-plugin.version>3.13.0</maven-pmd-plugin.version>
-        <lombok.version>1.16.12</lombok.version>
+        <lombok.version>1.18.20</lombok.version>
         <h2.version>1.4.197</h2.version>
     </properties>
 

spring-5-reactive-client/src/test/java/com/baeldung/reactive/logging/WebClientLoggingIntegrationTest.java

@@ -146,7 +146,7 @@ public class WebClientLoggingIntegrationTest {
           .exchange()
           .block();
 
-        verify(mockAppender).doAppend(argThat(argument -> (((LoggingEvent) argument).getFormattedMessage()).contains("domain=.typicode.com;")));
+        verify(mockAppender).doAppend(argThat(argument -> (((LoggingEvent) argument).getFormattedMessage()).contains(sampleUrl)));
     }
 
 

spring-boot-modules/pom.xml

@@ -70,7 +70,6 @@
         <module>spring-boot-swagger-jwt</module>
         <module>spring-boot-testing</module>
         <module>spring-boot-vue</module>
-        <module>spring-boot-xml</module>
         <module>spring-boot-actuator</module>
         <module>spring-boot-data-2</module>
         <module>spring-boot-react</module>

spring-boot-modules/spring-boot-admin/spring-boot-admin-client/pom.xml

@@ -60,7 +60,7 @@
     </build>
 
     <properties>
-        <spring-boot-admin-starter-client.version>2.4.0</spring-boot-admin-starter-client.version>
+        <spring-boot-admin-starter-client.version>2.4.1</spring-boot-admin-starter-client.version>
         <spring-boot-maven-plugin.version>2.0.4.RELEASE</spring-boot-maven-plugin.version>
     </properties>
 

spring-boot-modules/spring-boot-admin/spring-boot-admin-server/pom.xml

@@ -76,8 +76,8 @@
     </build>
 
     <properties>
-        <spring-boot-admin-server.version>2.4.0</spring-boot-admin-server.version>
-        <spring-boot-admin-starter-client.version>2.4.0</spring-boot-admin-starter-client.version>
+        <spring-boot-admin-server.version>2.4.1</spring-boot-admin-server.version>
+        <spring-boot-admin-starter-client.version>2.4.1</spring-boot-admin-starter-client.version>
         <spring-boot-admin-server-ui-login.version>1.5.7</spring-boot-admin-server-ui-login.version>
         <spring-boot-maven-plugin.version>2.0.4.RELEASE</spring-boot-maven-plugin.version>
     </properties>

spring-boot-modules/spring-boot-basic-customization-2/README.md

@@ -5,3 +5,4 @@ This module contains articles about Spring Boot customization 2
 ### Relevant Articles:
 
  - [DispatcherServlet and web.xml in Spring Boot](https://www.baeldung.com/spring-boot-dispatcherservlet-web-xml)
+ - [XML Defined Beans in Spring Boot](https://www.baeldung.com/spring-boot-xml-beans)

spring-boot-modules/spring-boot-basic-customization-2/pom.xml

@@ -23,7 +23,10 @@
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
-            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
         </dependency>
     </dependencies>
 

spring-boot-modules/spring-boot-basic-customization-2/src/main/resources/application.properties

@@ -0,0 +1 @@
+sample=string loaded from properties!

spring-boot-modules/spring-boot-basic-customization-2/src/main/test/com/baeldung/springbootxml/SpringBootXmlApplicationIntegrationTest.java

@@ -1,5 +1,6 @@
 package com.baeldung.springbootxml;
 
+
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;

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

@@ -0,0 +1,11 @@
+# Cassandre trading bot example
+
+This project is an example of a trading bot developed with Cassandre
+
+## Running the examples
+
+* `mvn test` - Run strategy backtesting
+* `mvn spring-boot:run` - Run the bot
+
+## Relevant Articles
+- [Build a Trading Bot with Cassandre Spring Boot Starter](https://www.baeldung.com/cassandre-spring-boot-trading-bot)

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

@@ -0,0 +1,68 @@
+<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.4.5</version>
+		<relativePath /> <!-- lookup parent from repository -->
+	</parent>
+	<groupId>com.example</groupId>
+	<artifactId>demo</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>Cassandre trading bot tutorial</name>
+	<description>Cassandre trading bot tutorial</description>
+	<properties>
+		<java.version>11</java.version>
+	</properties>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter</artifactId>
+		</dependency>
+
+		<!-- Cassandre dependencies -->
+		<dependency>
+			<groupId>tech.cassandre.trading.bot</groupId>
+			<artifactId>cassandre-trading-bot-spring-boot-starter</artifactId>
+			<version>4.2.1</version>
+		</dependency>
+		<dependency>
+			<groupId>org.knowm.xchange</groupId>
+			<artifactId>xchange-kucoin</artifactId>
+			<version>5.0.7</version>
+		</dependency>
+		<dependency>
+			<groupId>org.hsqldb</groupId>
+			<artifactId>hsqldb</artifactId>
+			<version>2.5.1</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<!-- Cassandre dependencies -->
+		<dependency>
+			<groupId>tech.cassandre.trading.bot</groupId>
+			<artifactId>cassandre-trading-bot-spring-boot-starter-test</artifactId>
+			<version>4.2.1</version>
+			<scope>test</scope>
+		</dependency>
+
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<version>2.4.5</version>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

spring-boot-modules/spring-boot-cassandre/src/main/java/com/example/demo/DemoApplication.java

@@ -0,0 +1,13 @@
+package com.example.demo;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class DemoApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(DemoApplication.class, args);
+    }
+
+}

spring-boot-modules/spring-boot-cassandre/src/main/java/com/example/demo/MyFirstStrategy.java

@@ -0,0 +1,66 @@
+package com.example.demo;
+
+import static tech.cassandre.trading.bot.dto.position.PositionStatusDTO.CLOSED;
+import static tech.cassandre.trading.bot.dto.position.PositionStatusDTO.OPENED;
+import static tech.cassandre.trading.bot.dto.util.CurrencyDTO.BTC;
+import static tech.cassandre.trading.bot.dto.util.CurrencyDTO.USDT;
+
+import java.math.BigDecimal;
+import java.util.Optional;
+import java.util.Set;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import tech.cassandre.trading.bot.dto.market.TickerDTO;
+import tech.cassandre.trading.bot.dto.position.PositionDTO;
+import tech.cassandre.trading.bot.dto.position.PositionRulesDTO;
+import tech.cassandre.trading.bot.dto.user.AccountDTO;
+import tech.cassandre.trading.bot.dto.util.CurrencyPairDTO;
+import tech.cassandre.trading.bot.strategy.BasicCassandreStrategy;
+import tech.cassandre.trading.bot.strategy.CassandreStrategy;
+
+@CassandreStrategy
+public class MyFirstStrategy extends BasicCassandreStrategy {
+
+    private final Logger logger = LoggerFactory.getLogger(MyFirstStrategy.class);
+
+    @Override
+    public Set<CurrencyPairDTO> getRequestedCurrencyPairs() {
+        return Set.of(new CurrencyPairDTO(BTC, USDT));
+    }
+
+    @Override
+    public Optional<AccountDTO> getTradeAccount(Set<AccountDTO> accounts) {
+        return accounts.stream()
+            .filter(a -> "trade".equals(a.getName()))
+            .findFirst();
+    }
+
+    @Override
+    public void onTickerUpdate(TickerDTO ticker) {
+        logger.info("Received a new ticker : {}", ticker);
+        
+        if (new BigDecimal("56000").compareTo(ticker.getLast()) == -1) {
+
+            if (canBuy(new CurrencyPairDTO(BTC, USDT), new BigDecimal("0.01"))) {
+                PositionRulesDTO rules = PositionRulesDTO.builder()
+                    .stopGainPercentage(4f)
+                    .stopLossPercentage(25f)
+                    .build();
+                createLongPosition(new CurrencyPairDTO(BTC, USDT), new BigDecimal("0.01"), rules);
+            }
+
+        }
+    }
+
+    @Override
+    public void onPositionStatusUpdate(PositionDTO position) {
+        if (position.getStatus() == OPENED) {
+            logger.info("> New position opened : {}", position.getPositionId());
+        }
+        if (position.getStatus() == CLOSED) {
+            logger.info("> Position closed : {}", position.getDescription());
+        }
+    }
+
+}

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

@@ -0,0 +1,22 @@
+#
+# Exchange configuration.
+cassandre.trading.bot.exchange.name=kucoin
+cassandre.trading.bot.exchange.username=kucoin.cassandre.test@gmail.com
+cassandre.trading.bot.exchange.passphrase=cassandre
+cassandre.trading.bot.exchange.key=6054ad25365ac6000689a998
+cassandre.trading.bot.exchange.secret=af080d55-afe3-47c9-8ec1-4b479fbcc5e7
+#
+# Modes
+cassandre.trading.bot.exchange.modes.sandbox=true
+cassandre.trading.bot.exchange.modes.dry=false
+#
+# Exchange API calls rates (ms or standard ISO 8601 duration like 'PT5S').
+cassandre.trading.bot.exchange.rates.account=2000
+cassandre.trading.bot.exchange.rates.ticker=2000
+cassandre.trading.bot.exchange.rates.trade=2000
+#
+# Database configuration.
+cassandre.trading.bot.database.datasource.driver-class-name=org.hsqldb.jdbc.JDBCDriver
+cassandre.trading.bot.database.datasource.url=jdbc:hsqldb:mem:cassandre
+cassandre.trading.bot.database.datasource.username=sa
+cassandre.trading.bot.database.datasource.password=

spring-boot-modules/spring-boot-cassandre/src/test/java/com/example/demo/DemoApplicationTests.java

@@ -0,0 +1,13 @@
+package com.example.demo;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class DemoApplicationTests {
+
+    @Test
+    void contextLoads() {
+    }
+
+}

spring-boot-modules/spring-boot-cassandre/src/test/java/com/example/demo/MyFirstStrategyUnitTest.java

@@ -0,0 +1,55 @@
+package com.example.demo;
+
+import static org.awaitility.Awaitility.await;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static tech.cassandre.trading.bot.dto.position.PositionStatusDTO.OPENED;
+import static tech.cassandre.trading.bot.dto.util.CurrencyDTO.USDT;
+
+import java.util.HashMap;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+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.context.annotation.Import;
+
+import tech.cassandre.trading.bot.dto.util.CurrencyDTO;
+import tech.cassandre.trading.bot.dto.util.GainDTO;
+import tech.cassandre.trading.bot.test.mock.TickerFluxMock;
+
+@SpringBootTest
+@Import(TickerFluxMock.class)
+@DisplayName("Simple strategy test")
+public class MyFirstStrategyUnitTest {
+
+    private final Logger logger = LoggerFactory.getLogger(MyFirstStrategyUnitTest.class);
+
+    @Autowired
+    private MyFirstStrategy strategy;
+
+    @Autowired
+    private TickerFluxMock tickerFluxMock;
+
+    @Test
+    @DisplayName("Check gains")
+    public void whenTickersArrives_thenCheckGains() {
+        await().forever().until(() -> tickerFluxMock.isFluxDone());
+
+        final HashMap<CurrencyDTO, GainDTO> gains = strategy.getGains();
+
+        logger.info("Cumulated gains:");
+        gains.forEach((currency, gain) -> logger.info(currency + " : " + gain.getAmount()));
+
+        logger.info("Position still opened :");
+        strategy.getPositions()
+                .values()
+                .stream()
+                .filter(p -> p.getStatus().equals(OPENED))
+                .forEach(p -> logger.info(" - {} " + p.getDescription()));
+
+        assertTrue(gains.get(USDT).getPercentage() > 0);
+    }
+    
+}

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

@@ -0,0 +1,22 @@
+#
+# Exchange configuration.
+cassandre.trading.bot.exchange.name=kucoin
+cassandre.trading.bot.exchange.username=kucoin.cassandre.test@gmail.com
+cassandre.trading.bot.exchange.passphrase=cassandre
+cassandre.trading.bot.exchange.key=6054ad25365ac6000689a998
+cassandre.trading.bot.exchange.secret=af080d55-afe3-47c9-8ec1-4b479fbcc5e7
+#
+# Modes
+cassandre.trading.bot.exchange.modes.sandbox=true
+cassandre.trading.bot.exchange.modes.dry=true
+#
+# Exchange API calls rates (ms or standard ISO 8601 duration like 'PT5S').
+cassandre.trading.bot.exchange.rates.account=2000
+cassandre.trading.bot.exchange.rates.ticker=2000
+cassandre.trading.bot.exchange.rates.trade=2000
+#
+# Database configuration.
+cassandre.trading.bot.database.datasource.driver-class-name=org.hsqldb.jdbc.JDBCDriver
+cassandre.trading.bot.database.datasource.url=jdbc:hsqldb:mem:cassandre
+cassandre.trading.bot.database.datasource.username=sa
+cassandre.trading.bot.database.datasource.password=

spring-boot-modules/spring-boot-cassandre/src/test/resources/tickers-btc-usdt.tsv

@@ -0,0 +1,89 @@
+1612569600	38294.4	39195.5	40964.2	38217.5	3882.29460938	153897343.463150723
+1612656000	39195.4	38807.6	39623.6	37341.4	2389.96820017	91972455.834535369
+1612742400	38807.6	46373.5	46767.9	38010	4971.54731481	212132648.426718929
+1612828800	46374.6	46434.8	48139.3	44961	4330.72854712	201891604.027160303
+1612915200	46430	44812.2	47300	43687.5	4351.84907778	198189685.592028516
+1613001600	44806.1	47941.5	48647.6	44005.8	4045.91883504	188171651.974437139
+1613088000	47963.1	47310.7	48958.8	46181.2	3356.01832119	159561721.419695848
+1613174400	47305.4	47152.6	48120.5	46225.5	2740.99221759	129227867.922246174
+1613260800	47152.5	48591.9	49686.9	47026.3	3359.4690565	163299915.839307312
+1613347200	48587.2	47904.4	49003.6	42841.6	3974.98461358	188990056.26923591
+1613433600	47913.1	49147.7	50619.3	47023.9	3599.85370182	176084748.845657596
+1613520000	49147.7	52118.1	52609.6	48931.1	3356.85082847	170893567.530348564
+1613606400	52114.3	51568.9	52522.9	50906.4	2183.18379408	113272339.172174965
+1613692800	51561.1	55890.5	56317.7	50727	3749.6920105	200656740.865959032
+1613779200	55893.6	55851.5	57622.6	53463.3	3394.87226216	190744601.429330887
+1613865600	55851.4	57423	58336.3	55489.6	2514.02340013	143658132.671448082
+1613952000	57420.6	54096.6	57517.8	44160	6125.32442907	330513978.457310237
+1614038400	54085.9	48908.3	54174.2	44900	8048.96505298	389277314.445372085
+1614124800	48902.9	49685.2	51361.9	47003.2	4816.75027676	239303706.844272809
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+1618531200	63152.6	61342.6	63509.7	59930.8	8295.32523869	510423835.691643255
+1618617600	61342.7	59995.2	62497.8	59599.6	5367.42979289	328364887.709585395
+1618704000	59995.3	56150.6	60409.5	49001	11485.97101449	637797282.448645379
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+1618963200	56426.1	53793.6	56761.7	53602	6240.82191836	345339357.806167462
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+1619136000	51691.2	51102.7	52112.1	47502.1	8885.07060366	441295812.644904319
+1619222400	51109.8	50033	51157.9	48676.5	4833.41744745	241336360.887795675
+1619308800	50041.5	49086.9	50554.6	46966.2	4805.34664069	237153315.222670555
+1619395200	49069	54000.2	54336.4	48775.8	6695.12934907	353727728.269533971
+1619481600	53997.1	55014.3	55439	53240.8	4344.22291318	237020455.905144335
+1619568000	55014.2	54833.2	56399.1	53808.3	4801.04618634	262912695.604761319
+1619654400	54833.1	53558.4	55181.2	52340.1	4356.05177188	234153663.397444462
+1619740800	53558.5	57697.3	57936.4	53042.6	5000.47557303	277531927.921795199
+1619827200	57697.3	57794.7	58471.4	57006.3	3639.78966647	210179438.189007639
+1619913600	57794.7	56568.5	57903.7	56044.3	3508.52428767	199206958.05741809
+1620000000	56568.5	57159.7	58977.9	56451.3	4780.43387226	276554749.540429296
+1620086400	57159.7	53196.3	57188.2	53083.3	7079.55804728	390469293.396018923
+1620172800	53196.3	57834.5	57979.7	52888	4224.63060355	233779565.506303973

spring-boot-modules/spring-boot-cassandre/src/test/resources/user-trade.tsv

@@ -0,0 +1,3 @@
+BTC	1
+USDT	100000
+ETH	10

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

@@ -8,6 +8,8 @@ import java.security.Principal;
 
 import org.springframework.beans.factory.annotation.Autowired;
 
+import javax.servlet.http.HttpServletRequest;
+
 @Controller
 public class WebController {
 
@@ -19,6 +21,12 @@ public class WebController {
         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();

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

@@ -27,6 +27,7 @@
 		</table>
 		<div id="pagefoot" th:include="layout :: footerFragment">Footer
 		</div>
+		<a href="/logout">Logout</a>
 	</div>
 	<!-- container -->
 </body>

spring-boot-modules/spring-boot-mvc-3/README.md

@@ -9,4 +9,5 @@ This module contains articles about Spring Web MVC in Spring Boot projects.
 - [Spring MVC Async vs Spring WebFlux](https://www.baeldung.com/spring-mvc-async-vs-webflux)
 - [Differences in @Valid and @Validated Annotations in Spring](https://www.baeldung.com/spring-valid-vs-validated)
 - [CharacterEncodingFilter In SpringBoot](https://www.baeldung.com/spring-boot-characterencodingfilter)
+- [HandlerInterceptors vs. Filters in Spring MVC](https://www.baeldung.com/spring-mvc-handlerinterceptor-vs-filter)
 - More articles: [[prev -->]](/spring-boot-modules/spring-boot-mvc-2)

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/FilterInterceptorApp.java

@@ -0,0 +1,11 @@
+package com.baeldung.filtersinterceptors;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication(scanBasePackages = "com.baeldung.filtersinterceptors")
+public class FilterInterceptorApp {
+    public static void main(String[] args) {
+        SpringApplication.run(FilterInterceptorApp.class, args);
+    }
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/HelloConroller.java

@@ -0,0 +1,19 @@
+package com.baeldung.filtersinterceptors;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+
+@Controller
+public class HelloConroller {
+
+    private Logger logger = LoggerFactory.getLogger(HelloConroller.class);
+
+    @GetMapping("/hello")
+    public String hello() {
+        logger.info("Hello from the controller");
+        return "hello";
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/LogFilter.java

@@ -0,0 +1,26 @@
+package com.baeldung.filtersinterceptors;
+
+import java.io.IOException;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+@Component
+public class LogFilter implements Filter {
+
+    private Logger logger = LoggerFactory.getLogger(LogFilter.class);
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+        logger.info("Hello from: " + request.getLocalAddr());
+        chain.doFilter(request, response);
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/LogInterceptor.java

@@ -0,0 +1,32 @@
+package com.baeldung.filtersinterceptors;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.HandlerInterceptor;
+import org.springframework.web.servlet.ModelAndView;
+
+public class LogInterceptor implements HandlerInterceptor {
+
+    private Logger logger = LoggerFactory.getLogger(LogInterceptor.class);
+
+    @Override
+    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
+        logger.info("preHandle");
+        return true;
+    }
+
+    @Override
+    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
+        logger.info("postHandle");
+    }
+
+    @Override
+    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
+        logger.info("afterCompletion");
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/filtersinterceptors/WebMvcConfig.java

@@ -0,0 +1,15 @@
+package com.baeldung.filtersinterceptors;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+@Configuration
+public class WebMvcConfig implements WebMvcConfigurer {
+
+    @Override
+    public void addInterceptors(InterceptorRegistry registry) {
+        registry.addInterceptor(new LogInterceptor());
+    }
+
+}

spring-boot-modules/spring-boot-mvc-3/src/main/resources/templates/hello.html

@@ -0,0 +1,10 @@
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Spring Filters vs Interceptors</title>
+</head>
+
+<body>
+	<h3>Hello</h3>
+</body>
+</html>

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

@@ -1,3 +0,0 @@
-### Relevant Articles:
-
-- [XML Defined Beans in Spring Boot](https://www.baeldung.com/spring-boot-xml-beans)