Merge branch 'master' into feature/BAEL-7419-how-to-mock-aws-s3-for-integration-test

.gitignore

@@ -64,13 +64,13 @@ core-java-io/hard_link.txt
 core-java-io/target_link.txt
 core-java/src/main/java/com/baeldung/manifest/MANIFEST.MF
 ethereum/logs/
-jmeter/src/main/resources/*-JMeter.csv
-jmeter/src/main/resources/*-Basic*.csv
-jmeter/src/main/resources/*-JMeter*.csv
-jmeter/src/main/resources/*ReportsDashboard*.csv
-jmeter/src/main/resources/dashboard/*ReportsDashboard*.csv
-jmeter/src/main/resources/*FileExtractionExample.csv
-jmeter/src/main/resources/*_Summary-Report.csv
+testing-modules/jmeter/src/main/resources/*-JMeter.csv
+testing-modules/jmeter/src/main/resources/*-Basic*.csv
+testing-modules/jmeter/src/main/resources/*-JMeter*.csv
+testing-modules/jmeter/src/main/resources/*ReportsDashboard*.csv
+testing-modules/jmeter/src/main/resources/dashboard/*ReportsDashboard*.csv
+testing-modules/jmeter/src/main/resources/*FileExtractionExample.csv
+testing-modules/jmeter/src/main/resources/*_Summary-Report.csv
 
 ninja/devDb.mv.db
 
@@ -128,3 +128,6 @@ persistence-modules/neo4j/data/**
 /deep-shallow-copy/.mvn/wrapper
 /deep-shallow-copy/mvnw
 /deep-shallow-copy/mvnw.cmd
+
+#spring-5-webflux-2
+**/testdb.mv.db

algorithms-modules/algorithms-miscellaneous-2/pom.xml

@@ -14,16 +14,6 @@
     </parent>
 
     <dependencies>
-        <dependency>
-            <groupId>org.apache.commons</groupId>
-            <artifactId>commons-math3</artifactId>
-            <version>${commons-math3.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>commons-codec</groupId>
-            <artifactId>commons-codec</artifactId>
-            <version>${commons-codec.version}</version>
-        </dependency>
         <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/DijkstraAlgorithmLongRunningUnitTest.java

@@ -1,7 +1,5 @@
 package com.baeldung.algorithms;
 
-
-
 import com.baeldung.algorithms.ga.dijkstra.Dijkstra;
 import com.baeldung.algorithms.ga.dijkstra.Graph;
 import com.baeldung.algorithms.ga.dijkstra.Node;

algorithms-modules/algorithms-miscellaneous-7/README.md

@@ -6,4 +6,6 @@
 - [Calculate Distance Between Two Coordinates in Java](https://www.baeldung.com/java-find-distance-between-points)
 - [Rotate Arrays in Java](https://www.baeldung.com/java-rotate-arrays)
 - [Find Missing Number From a Given Array in Java](https://www.baeldung.com/java-array-find-missing-number)
+- [Calculate Weighted Mean in Java](https://www.baeldung.com/java-compute-weighted-average)
+- [Check if Two Strings Are Rotations of Each Other](https://www.baeldung.com/java-string-check-strings-rotations)
 - More articles: [[<-- prev]](/algorithms-miscellaneous-6)

algorithms-modules/algorithms-miscellaneous-7/src/main/java/com/baeldung/algorithms/primeundernumber/LargestPrimeFinder.java

@@ -0,0 +1,43 @@
+package com.baeldung.algorithms.primeundernumber;
+
+import java.util.Arrays;
+
+public class LargestPrimeFinder {
+
+    public static int findByBruteForce(int n) {
+        for (int i = n - 1; i >= 2; i--) {
+            if (isPrime(i)) {
+                return i;
+            }
+        }
+        return -1; // Return -1 if no prime number is found
+    }
+
+    public static boolean isPrime(int number) {
+        for (int i = 2; i <= Math.sqrt(number); i++) {
+            if (number % i == 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static int findBySieveOfEratosthenes(int n) {
+        boolean[] isPrime = new boolean[n];
+        Arrays.fill(isPrime, true);
+        for (int p = 2; p*p < n; p++) {
+            if (isPrime[p]) {
+                for (int i = p * p; i < n; i += p) {
+                    isPrime[i] = false;
+                }
+            }
+        }
+
+        for (int i = n - 1; i >= 2; i--) {
+            if (isPrime[i]) {
+                return i;
+            }
+        }
+        return -1;
+    }
+}

algorithms-modules/algorithms-miscellaneous-7/src/main/java/com/baeldung/algorithms/stringrotation/StringRotation.java

@@ -0,0 +1,123 @@
+package com.baeldung.algorithms.stringrotation;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class StringRotation {
+
+    public static boolean doubledOriginContainsRotation(String origin, String rotation) {
+        if (origin.length() == rotation.length()) {
+            return origin.concat(origin)
+              .contains(rotation);
+        }
+
+        return false;
+    }
+
+    public static boolean isRotationUsingCommonStartWithOrigin(String origin, String rotation) {
+
+        if (origin.length() == rotation.length()) {
+
+            List<Integer> indexes = IntStream.range(0, origin.length())
+              .filter(i -> rotation.charAt(i) == origin.charAt(0))
+              .boxed()
+              .collect(Collectors.toList());
+
+            for (int startingAt : indexes) {
+                if (isRotation(startingAt, rotation, origin)) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    static boolean isRotation(int startingAt, String rotation, String origin) {
+
+        for (int i = 0; i < origin.length(); i++) {
+            if (rotation.charAt((startingAt + i) % origin.length()) != origin.charAt(i)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    public static boolean isRotationUsingQueue(String origin, String rotation) {
+
+        if (origin.length() == rotation.length()) {
+            return checkWithQueue(origin, rotation);
+        }
+
+        return false;
+    }
+
+    static boolean checkWithQueue(String origin, String rotation) {
+
+        if (origin.length() == rotation.length()) {
+
+            Queue<Character> originQueue = getCharactersQueue(origin);
+
+            Queue<Character> rotationQueue = getCharactersQueue(rotation);
+
+            int k = rotation.length();
+            while (k > 0 && null != rotationQueue.peek()) {
+                k--;
+                char ch = rotationQueue.peek();
+                rotationQueue.remove();
+                rotationQueue.add(ch);
+                if (rotationQueue.equals(originQueue)) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    static Queue<Character> getCharactersQueue(String origin) {
+        return origin.chars()
+          .mapToObj(c -> (char) c)
+          .collect(Collectors.toCollection(LinkedList::new));
+    }
+
+    public static boolean isRotationUsingSuffixAndPrefix(String origin, String rotation) {
+
+        if (origin.length() == rotation.length()) {
+            return checkPrefixAndSuffix(origin, rotation);
+        }
+
+        return false;
+    }
+
+    static boolean checkPrefixAndSuffix(String origin, String rotation) {
+        if (origin.length() == rotation.length()) {
+
+            for (int i = 0; i < origin.length(); i++) {
+                if (origin.charAt(i) == rotation.charAt(0)) {
+                    if (checkRotationPrefixWithOriginSuffix(origin, rotation, i)) {
+                        if (checkOriginPrefixWithRotationSuffix(origin, rotation, i))
+                            return true;
+                    }
+                }
+            }
+
+        }
+
+        return false;
+    }
+
+    private static boolean checkRotationPrefixWithOriginSuffix(String origin, String rotation, int i) {
+        return origin.substring(i)
+          .equals(rotation.substring(0, origin.length() - i));
+    }
+
+    private static boolean checkOriginPrefixWithRotationSuffix(String origin, String rotation, int i) {
+        return origin.substring(0, i)
+          .equals(rotation.substring(origin.length() - i));
+    }
+}

algorithms-modules/algorithms-miscellaneous-7/src/test/java/com/baeldung/algorithms/primeundernumber/LargestPrimeFinderUnitTest.java

@@ -0,0 +1,32 @@
+package com.baeldung.algorithms.primeundernumber;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class LargestPrimeFinderUnitTest {
+
+    @Test
+    public void givenNormalCases_whenFindPrime_ThenFoundResult() {
+        assertEquals(7, LargestPrimeFinder.findByBruteForce(10));
+        assertEquals(97, LargestPrimeFinder.findByBruteForce(100));
+        assertEquals(7, LargestPrimeFinder.findBySieveOfEratosthenes(10));
+        assertEquals(97, LargestPrimeFinder.findBySieveOfEratosthenes(100));
+    }
+
+    @Test
+    public void givenEdgeCases_whenFindPrime_ThenNotFoundResult() {
+        assertEquals(-1, LargestPrimeFinder.findByBruteForce(0));
+        assertEquals(-1, LargestPrimeFinder.findByBruteForce(1));
+        assertEquals(-1, LargestPrimeFinder.findByBruteForce(2));
+        assertEquals(-1, LargestPrimeFinder.findBySieveOfEratosthenes(0));
+        assertEquals(-1, LargestPrimeFinder.findBySieveOfEratosthenes(1));
+        assertEquals(-1, LargestPrimeFinder.findBySieveOfEratosthenes(2));
+    }
+
+    @Test
+    public void givenLargeInput_whenFindPrime_ThenFoundResult() {
+        assertEquals(99991, LargestPrimeFinder.findByBruteForce(100000));
+        assertEquals(99991, LargestPrimeFinder.findBySieveOfEratosthenes(100000));
+    }
+}

algorithms-modules/algorithms-miscellaneous-7/src/test/java/com/baeldung/algorithms/stringrotation/StringRotationUnitTest.java

@@ -0,0 +1,61 @@
+package com.baeldung.algorithms.stringrotation;
+
+import static com.baeldung.algorithms.stringrotation.StringRotation.doubledOriginContainsRotation;
+import static com.baeldung.algorithms.stringrotation.StringRotation.isRotationUsingCommonStartWithOrigin;
+import static com.baeldung.algorithms.stringrotation.StringRotation.isRotationUsingQueue;
+import static com.baeldung.algorithms.stringrotation.StringRotation.isRotationUsingSuffixAndPrefix;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class StringRotationUnitTest {
+
+    @Test
+    void givenOriginAndRotationInput_whenCheckIfOriginContainsRotation_thenIsRotation() {
+        assertTrue(doubledOriginContainsRotation("abcd", "cdab"));
+        assertTrue(doubledOriginContainsRotation("abcd", "abcd"));
+    }
+
+    @Test
+    void givenOriginAndRotationInput_whenCheckIfOriginContainsRotation_thenNoRotation() {
+        assertFalse(doubledOriginContainsRotation("abcd", "bbbb"));
+        assertFalse(doubledOriginContainsRotation("abcd", "abcde"));
+    }
+
+    @Test
+    void givenOriginAndRotationInput_whenCheckingCommonStartWithOrigin_thenIsRotation() {
+        assertTrue(isRotationUsingCommonStartWithOrigin("abcd", "cdab"));
+        assertTrue(isRotationUsingCommonStartWithOrigin("abcd", "abcd"));
+    }
+
+    @Test
+    void givenOriginAndRotationInput_whenCheckingCommonStartWithOrigin_thenNoRotation() {
+        assertFalse(isRotationUsingCommonStartWithOrigin("abcd", "bbbb"));
+        assertFalse(isRotationUsingCommonStartWithOrigin("abcd", "abcde"));
+    }
+
+    @Test
+    void givenOriginAndRotationInput_whenCheckingUsingQueues_thenIsRotation() {
+        assertTrue(isRotationUsingQueue("abcd", "cdab"));
+        assertTrue(isRotationUsingQueue("abcd", "abcd"));
+    }
+
+    @Test
+    void givenOriginAndRotationInput_whenCheckingUsingQueues_thenNoRotation() {
+        assertFalse(isRotationUsingQueue("abcd", "bbbb"));
+        assertFalse(isRotationUsingQueue("abcd", "abcde"));
+    }
+
+    @Test
+    void givenOriginAndRotationInput_whenCheckingUsingSuffixAndPrefix_thenIsRotation() {
+        assertTrue(isRotationUsingSuffixAndPrefix("abcd", "cdab"));
+        assertTrue(isRotationUsingSuffixAndPrefix("abcd", "abcd"));
+    }
+
+    @Test
+    void givenOriginAndRotationInput_whenCheckingUsingSuffixAndPrefix_thenNoRotation() {
+        assertFalse(isRotationUsingSuffixAndPrefix("abcd", "bbbb"));
+        assertFalse(isRotationUsingSuffixAndPrefix("abcd", "abcde"));
+    }
+}

algorithms-modules/algorithms-miscellaneous-7/src/test/java/com/baeldung/algorithms/weightedaverage/WeightedAverageUnitTest.java

@@ -0,0 +1,153 @@
+package com.baeldung.algorithms.weightedaverage;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.*;
+import java.util.function.BiConsumer;
+import java.util.function.BinaryOperator;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collector;
+import java.util.stream.IntStream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class WeightedAverageUnitTest {
+
+    private List<Values> values = Arrays.asList(
+            new Values(1, 10),
+            new Values(3, 20),
+            new Values(5, 30),
+            new Values(7, 50),
+            new Values(9, 40)
+    );
+
+    private Double expected = 6.2;
+
+    @Test
+    void twoPass() {
+        double top = values.stream()
+                .mapToDouble(v -> v.value * v.weight)
+                .sum();
+        double bottom = values.stream()
+                .mapToDouble(v -> v.weight)
+                .sum();
+
+        double result = top / bottom;
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void onePass() {
+        double top = 0;
+        double bottom = 0;
+
+        for (Values v : values) {
+            top += (v.value * v.weight);
+            bottom += v.weight;
+        }
+
+        double result = top / bottom;
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void expanding() {
+        double result = values.stream()
+                .flatMap(v -> Collections.nCopies(v.weight, v.value).stream())
+                .mapToInt(v -> v)
+                .average()
+                .getAsDouble();
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void reduce() {
+        class WeightedAverage {
+            final double top;
+            final double bottom;
+
+            public WeightedAverage(double top, double bottom) {
+                this.top = top;
+                this.bottom = bottom;
+            }
+
+            double average() {
+                return top / bottom;
+            }
+        }
+
+        double result = values.stream()
+                .reduce(new WeightedAverage(0, 0),
+                        (acc, next) -> new WeightedAverage(
+                                acc.top + (next.value * next.weight),
+                                acc.bottom + next.weight),
+                        (left, right) -> new WeightedAverage(
+                                left.top + right.top,
+                                left.bottom + right.bottom))
+                .average();
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void customCollector() {
+        class WeightedAverage implements Collector<Values, WeightedAverage.RunningTotals, Double> {
+            class RunningTotals {
+                double top;
+                double bottom;
+
+                public RunningTotals() {
+                    this.top = 0;
+                    this.bottom = 0;
+                }
+            }
+
+            @Override
+            public Supplier<RunningTotals> supplier() {
+                return RunningTotals::new;
+            }
+
+            @Override
+            public BiConsumer<RunningTotals, Values> accumulator() {
+                return (current, next) -> {
+                    current.top += (next.value * next.weight);
+                    current.bottom += next.weight;
+                };
+            }
+
+            @Override
+            public BinaryOperator<RunningTotals> combiner() {
+                return (left, right) -> {
+                    left.top += right.top;
+                    left.bottom += right.bottom;
+
+                    return left;
+                };
+            }
+
+            @Override
+            public Function<RunningTotals, Double> finisher() {
+                return rt -> rt.top / rt.bottom;
+            }
+
+            @Override
+            public Set<Characteristics> characteristics() {
+                return Collections.singleton(Characteristics.UNORDERED);
+            }
+        }
+
+        double result = values.stream()
+                .collect(new WeightedAverage());
+        assertEquals(expected, result);
+    }
+
+    private static class Values {
+        int value;
+        int weight;
+
+        public Values(int value, int weight) {
+            this.value = value;
+            this.weight = weight;
+        }
+    }
+}

algorithms-modules/algorithms-searching/README.md

@@ -13,3 +13,4 @@ This module contains articles about searching algorithms.
 - [Range Search Algorithm in Java](https://www.baeldung.com/java-range-search)
 - [Fast Pattern Matching of Strings Using Suffix Tree in Java](https://www.baeldung.com/java-pattern-matching-suffix-tree)
 - [Find the Kth Smallest Element in Two Sorted Arrays in Java](https://www.baeldung.com/java-kth-smallest-element-in-sorted-arrays)
+- [Find the First Non-repeating Element of a List](https://www.baeldung.com/java-list-find-first-non-repeating-element)

algorithms-modules/algorithms-searching/src/main/java/com/baeldung/algorithms/firstnonrepeating/FirstNonRepeatingElement.java

@@ -0,0 +1,61 @@
+package com.baeldung.algorithms.firstnonrepeating;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class FirstNonRepeatingElement {
+    public static Integer findFirstNonRepeatingUsingForLoop(List<Integer> list) {
+        for (int i = 0; i < list.size(); i++) {
+            int current = list.get(i);
+            boolean isRepeating = false;
+            for (int j = 0; j < list.size(); j++) {
+                if (i != j && current == list.get(j)) {
+                    isRepeating = true;
+                    break;
+                }
+            }
+            if (!isRepeating) {
+                return current;
+            }
+        }
+        return null;
+    }
+
+    public static Integer findFirstNonRepeatedElementUsingIndex(List<Integer> list) {
+        for (int i = 0; i < list.size(); i++) {
+            if (list.indexOf(list.get(i)) == list.lastIndexOf(list.get(i))) {
+                return list.get(i);
+            }
+        }
+        return null;
+    }
+
+    public static Integer findFirstNonRepeatingUsingHashMap(List<Integer> list) {
+        Map<Integer, Integer> counts = new HashMap<>();
+        for (int num : list) {
+            counts.put(num, counts.getOrDefault(num, 0) + 1);
+        }
+        for (int num : list) {
+            if (counts.get(num) == 1) {
+                return num;
+            }
+        }
+        return null;
+    }
+
+    public static Integer findFirstNonRepeatingUsingArray(List<Integer> list) {
+        int maxElement = Collections.max(list);
+        int[] frequency = new int[maxElement + 1];
+        for (int num : list) {
+            frequency[num]++;
+        }
+        for (int num : list) {
+            if (frequency[num] == 1) {
+                return num;
+            }
+        }
+        return null;
+    }
+}

algorithms-modules/algorithms-searching/src/test/java/com/baeldung/algorithms/firstnonrepeating/FirstNonRepeatingElementUnitTest.java

@@ -0,0 +1,43 @@
+package com.baeldung.algorithms.firstnonrepeating;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class FirstNonRepeatingElementUnitTest {
+
+    private List<Integer> list;
+
+    @BeforeEach
+    void setUp() {
+        list = Arrays.asList(1, 2, 3, 2, 1, 4, 5, 4);
+    }
+
+    @Test
+    void whenUsingForLoop_thenReturnFirstNonRepeatingElement() {
+        int result = FirstNonRepeatingElement.findFirstNonRepeatingUsingForLoop(list);
+        assertEquals(3, result);
+    }
+
+    @Test
+    void whenUsingIndexOf_thenReturnFirstNonRepeatingElement() {
+        int result = FirstNonRepeatingElement.findFirstNonRepeatedElementUsingIndex(list);
+        assertEquals(3, result);
+    }
+
+    @Test
+    void whenUsingHashMap_thenReturnFirstNonRepeatingElement() {
+        int result = FirstNonRepeatingElement.findFirstNonRepeatingUsingHashMap(list);
+        assertEquals(3, result);
+    }
+
+    @Test
+    void whenUsingArray_thenReturnFirstNonRepeatingElement() {
+        int result = FirstNonRepeatingElement.findFirstNonRepeatingUsingArray(list);
+        assertEquals(3, result);
+    }
+}

apache-cxf-modules/cxf-aegis/pom.xml

@@ -20,8 +20,4 @@
         </dependency>
     </dependencies>
 
-    <properties>
-        <cxf.version>4.0.0</cxf.version>
-    </properties>
-
 </project>

apache-cxf-modules/cxf-introduction/pom.xml

@@ -48,7 +48,6 @@
     </build>
 
     <properties>
-        <cxf.version>4.0.0</cxf.version>
         <jakarta-xml.version>4.0.0</jakarta-xml.version>
         <jakarta.jws.version>3.0.0</jakarta.jws.version>
     </properties>

apache-cxf-modules/cxf-jaxrs-implementation/pom.xml

@@ -16,12 +16,12 @@
         <dependency>
             <groupId>org.apache.cxf</groupId>
             <artifactId>cxf-rt-frontend-jaxrs</artifactId>
-            <version>4.0.0</version>
+            <version>${cxf.version}</version>
         </dependency>
         <dependency>
             <groupId>org.apache.cxf</groupId>
             <artifactId>cxf-rt-transports-http-jetty</artifactId>
-            <version>4.0.0</version>
+            <version>${cxf.version}</version>
         </dependency>
         <dependency>
             <groupId>jakarta.xml.ws</groupId>

apache-cxf-modules/cxf-spring/pom.xml

@@ -115,6 +115,7 @@
     </profiles>
 
     <properties>
+        <cxf.version>3.1.8</cxf.version>
         <spring.version>5.3.25</spring.version>
         <cargo-maven2-plugin.version>1.6.1</cargo-maven2-plugin.version>
         <jstl.version>1.2</jstl.version>

apache-cxf-modules/pom.xml

@@ -35,7 +35,7 @@
     </build>
 
     <properties>
-        <cxf.version>3.1.8</cxf.version>
+        <cxf.version>4.0.0</cxf.version>
     </properties>
 
 </project>

apache-cxf-modules/sse-jaxrs/sse-jaxrs-client/pom.xml

@@ -16,12 +16,12 @@
         <dependency>
             <groupId>org.apache.cxf</groupId>
             <artifactId>cxf-rt-rs-client</artifactId>
-            <version>${cxf-version}</version>
+            <version>${cxf.version}</version>
         </dependency>
         <dependency>
             <groupId>org.apache.cxf</groupId>
             <artifactId>cxf-rt-rs-sse</artifactId>
-            <version>${cxf-version}</version>
+            <version>${cxf.version}</version>
         </dependency>
         <dependency>
             <groupId>jakarta.ws.rs</groupId>
@@ -60,7 +60,6 @@
     </build>
 
     <properties>
-        <cxf-version>4.0.0</cxf-version>
         <jakarta-ws.version>3.1.0</jakarta-ws.version>
     </properties>
 

apache-libraries-2/README.md

@@ -1,2 +1,3 @@
 ## Relevant Articles
 - [Understanding XSLT Processing in Java](https://www.baeldung.com/java-extensible-stylesheet-language-transformations)
+- [Add Camel Route at Runtime in Java](https://www.baeldung.com/java-camel-dynamic-route)

apache-libraries-2/pom.xml

@@ -19,10 +19,29 @@
             <artifactId>validation-api</artifactId>
             <version>${javax.validation.validation-api.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.apache.camel</groupId>
+            <artifactId>camel-core</artifactId>
+            <version>${camel.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.camel</groupId>
+            <artifactId>camel-test-junit5</artifactId>
+            <version>${camel.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.camel</groupId>
+            <artifactId>camel-main</artifactId>
+            <version>${camel.version}</version>
+        </dependency>
     </dependencies>
 
     <properties>
         <javax.validation.validation-api.version>2.0.1.Final</javax.validation.validation-api.version>
+        <camel.version>4.3.0</camel.version>
     </properties>
 
 </project>

apache-libraries-2/src/main/java/com/baeldung/dynamicrouter/DynamicRouterBean.java

@@ -0,0 +1,29 @@
+package com.baeldung.dynamicrouter;
+
+import org.apache.camel.ExchangeProperties;
+
+import java.util.Map;
+
+public class DynamicRouterBean {
+    public String route(String body, @ExchangeProperties Map<String, Object> properties) {
+        int invoked = (int) properties.getOrDefault("invoked", 0) + 1;
+
+        properties.put("invoked", invoked);
+
+        if (invoked == 1) {
+            switch (body.toLowerCase()) {
+                case "mock":
+                    return "mock:dynamicRouter";
+                case "direct":
+                    return "mock:directDynamicRouter";
+                case "seda":
+                    return "mock:sedaDynamicRouter";
+                case "file":
+                    return "mock:fileDynamicRouter";
+                default:
+                    break;
+            }
+        }
+        return null;
+    }
+}

apache-libraries-2/src/main/java/com/baeldung/dynamicrouter/DynamicRouterRoute.java

@@ -0,0 +1,13 @@
+package com.baeldung.dynamicrouter;
+
+import org.apache.camel.builder.RouteBuilder;
+
+public class DynamicRouterRoute extends RouteBuilder {
+
+    @Override
+    public void configure() {
+
+        from("direct:dynamicRouter").dynamicRouter(method(DynamicRouterBean.class, "route"));
+
+    }
+}

apache-libraries-2/src/main/resources/logback.xml

@@ -10,4 +10,6 @@
     <root level="INFO">
         <appender-ref ref="STDOUT" />
     </root>
+
+    <logger name="org.apache.camel.impl.engine" level="WARN"/>
 </configuration>

apache-libraries-2/src/test/java/dynamicrouter/DynamicRouterRouteUnitTest.java

@@ -0,0 +1,61 @@
+package dynamicrouter;
+
+import com.baeldung.dynamicrouter.DynamicRouterRoute;
+import org.apache.camel.RoutesBuilder;
+import org.apache.camel.component.mock.MockEndpoint;
+import org.apache.camel.test.junit5.CamelTestSupport;
+import org.junit.jupiter.api.Test;
+
+public class DynamicRouterRouteUnitTest extends CamelTestSupport {
+
+    @Override
+    protected RoutesBuilder createRouteBuilder() {
+        return new DynamicRouterRoute();
+    }
+
+    @Test
+    void givenDynamicRouter_whenMockEndpointExpectedMessageCountOneAndMockAsMessageBody_thenMessageSentToDynamicRouter() throws InterruptedException {
+
+        MockEndpoint mockDynamicEndpoint = getMockEndpoint("mock:dynamicRouter");
+        mockDynamicEndpoint.expectedMessageCount(1);
+
+        template.send("direct:dynamicRouter", exchange -> exchange.getIn()
+            .setBody("mock"));
+        MockEndpoint.assertIsSatisfied(context);
+    }
+
+    @Test
+    void givenDynamicRouter_whenMockEndpointExpectedMessageCountOneAndDirectAsMessageBody_thenMessageSentToDynamicRouter() throws InterruptedException {
+
+        MockEndpoint mockDynamicEndpoint = context.getEndpoint("mock:directDynamicRouter", MockEndpoint.class);
+        mockDynamicEndpoint.expectedMessageCount(1);
+
+        template.send("direct:dynamicRouter", exchange -> exchange.getIn()
+            .setBody("direct"));
+
+        MockEndpoint.assertIsSatisfied(context);
+    }
+
+    @Test
+    void givenDynamicRouter_whenMockEndpointExpectedMessageCountOneAndSedaAsMessageBody_thenMessageSentToDynamicRouter() throws InterruptedException {
+
+        MockEndpoint mockDynamicEndpoint = context.getEndpoint("mock:sedaDynamicRouter", MockEndpoint.class);
+        mockDynamicEndpoint.expectedMessageCount(1);
+
+        template.send("direct:dynamicRouter", exchange -> exchange.getIn()
+            .setBody("seda"));
+        MockEndpoint.assertIsSatisfied(context);
+    }
+
+    @Test
+    void givenDynamicRouter_whenMockEndpointExpectedMessageCountOneAndBookAsMessageBody_thenMessageSentToDynamicRouter() throws InterruptedException {
+
+        MockEndpoint mockDynamicEndpoint = getMockEndpoint("mock:fileDynamicRouter");
+        mockDynamicEndpoint.expectedMessageCount(1);
+
+        template.send("direct:dynamicRouter", exchange -> exchange.getIn()
+            .setBody("file"));
+        MockEndpoint.assertIsSatisfied(context);
+    }
+
+}

apache-libraries-2/src/test/resources/logback-test.xml

@@ -0,0 +1,15 @@
+<?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>
+
+    <logger name="ch.qos.logback.classic.joran.action" level="WARN"/>
+</configuration>

apache-libraries/pom.xml

@@ -191,7 +191,7 @@
         <bval.version>2.0.6</bval.version>
         <javax.validation.validation-api.version>2.0.1.Final</javax.validation.validation-api.version>
         <meecrowave-junit.version>1.2.15</meecrowave-junit.version>
-        <okhttp.version>4.12.0</okhttp.version>
+        <okhttp.version>5.0.0-alpha.12</okhttp.version>
         <meecrowave-jpa.version>1.2.15</meecrowave-jpa.version>
         <meecrowave-core.version>1.2.15</meecrowave-core.version>
         <meecrowave-maven-plugin.version>1.2.15</meecrowave-maven-plugin.version>

apache-poi-2/README.md

@@ -14,4 +14,4 @@ This module contains articles about Apache POI.
 - [Set the Date Format Using Apache POI](https://www.baeldung.com/java-apache-poi-date-format)
 - [Replacing Variables in a Document Template with Java](https://www.baeldung.com/java-replace-pattern-word-document-doc-docx)
 - [Lock Header Rows With Apache POI](https://www.baeldung.com/java-apache-poi-lock-header-rows)
-- More articles: [[<-- prev]](../apache-poi)
+- More articles: [[<-- prev]](../apache-poi)[[next -->]](../apache-poi-3)

apache-poi-2/pom.xml

@@ -27,7 +27,7 @@
     </dependencies>
 
     <properties>
-        <poi.version>5.2.3</poi.version>
+        <poi.version>5.2.5</poi.version>
     </properties>
 
 </project>

apache-poi-3/README.md

@@ -1,3 +1,10 @@
-## Relevant Articles
+## Apache POI
+
+This module contains articles about Apache POI.
+
+### Relevant Articles:
+
 - [How To Convert Excel Data Into List Of Java Objects](https://www.baeldung.com/java-convert-excel-data-into-list)
 - [Expand Columns with Apache POI](https://www.baeldung.com/java-apache-poi-expand-columns)
+- [Apply Bold Text Style for an Entire Row Using Apache POI](https://www.baeldung.com/appache-poi-apply-bold-text-style-entire-row)
+- More articles: [[<-- prev]](../apache-poi-2)

apache-poi-3/pom.xml

@@ -24,50 +24,41 @@
             <artifactId>poi-scratchpad</artifactId>
             <version>${poi.version}</version>
         </dependency>
-        <!-- https://mvnrepository.com/artifact/com.github.ozlerhakan/poiji -->
         <dependency>
             <groupId>com.github.ozlerhakan</groupId>
             <artifactId>poiji</artifactId>
             <version>${poiji.version}</version>
         </dependency>
-
-        <!-- https://mvnrepository.com/artifact/org.apache.poi/poi/5.2.3 -->
         <dependency>
             <groupId>org.apache.poi</groupId>
             <artifactId>poi</artifactId>
             <version>${poi.version}</version>
         </dependency>
-        <!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml-schemas/4.1.2 -->
         <dependency>
             <groupId>org.apache.poi</groupId>
             <artifactId>poi-ooxml-schemas</artifactId>
-            <version>4.1.2</version>
+            <version>${poi-ooxml-schemas.version}</version>
         </dependency>
-        <!-- https://mvnrepository.com/artifact/org.apache.xmlbeans/xmlbeans/5.1.1 -->
         <dependency>
             <groupId>org.apache.xmlbeans</groupId>
             <artifactId>xmlbeans</artifactId>
-            <version>5.1.1</version>
+            <version>${xmlbeans.version}</version>
         </dependency>
-        <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-collections4 -->
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-collections4</artifactId>
-            <version>4.4</version>
+            <version>${commons-collections4.version}</version>
         </dependency>
-        <!-- https://mvnrepository.com/artifact/org.dhatim/fastexcel/0.15.7 -->
         <dependency>
             <groupId>org.dhatim</groupId>
             <artifactId>fastexcel</artifactId>
             <version>${fastexcel.version}</version>
         </dependency>
-        <!-- https://mvnrepository.com/artifact/org.dhatim/fastexcel-reader/0.15.7 -->
         <dependency>
             <groupId>org.dhatim</groupId>
             <artifactId>fastexcel-reader</artifactId>
             <version>${fastexcel.version}</version>
         </dependency>
-        <!-- https://mvnrepository.com/artifact/net.sourceforge.jexcelapi/jxl/2.6.12 -->
         <dependency>
             <groupId>net.sourceforge.jexcelapi</groupId>
             <artifactId>jxl</artifactId>
@@ -77,8 +68,11 @@
 
     <properties>
         <poi.version>5.2.5</poi.version>
-        <poiji.version>4.1.1</poiji.version>
-        <fastexcel.version>0.15.7</fastexcel.version>
+        <poi-ooxml-schemas.version>4.1.2</poi-ooxml-schemas.version>
+        <poiji.version>4.2.0</poiji.version>
+        <xmlbeans.version>5.2.0</xmlbeans.version>
+        <commons-collections4.version>4.4</commons-collections4.version>
+        <fastexcel.version>0.17.0</fastexcel.version>
         <jxl.version>2.6.12</jxl.version>
     </properties>
 

apache-poi/pom.xml

@@ -60,10 +60,10 @@
     </build>
 
     <properties>
-        <poi.version>5.2.0</poi.version>
-        <jexcel.version>1.0.6</jexcel.version>
-        <fastexcel.version>0.15.3</fastexcel.version>
-        <maven.resources.plugin.version>3.2.0</maven.resources.plugin.version>
+        <poi.version>5.2.5</poi.version>
+        <jexcel.version>1.0.9</jexcel.version>
+        <fastexcel.version>0.17.0</fastexcel.version>
+        <maven.resources.plugin.version>3.3.1</maven.resources.plugin.version>
     </properties>
 
 </project>

aws-modules/aws-lambda-modules/lambda-function/pom.xml

@@ -97,7 +97,7 @@
         <json-simple.version>1.1.1</json-simple.version>
         <aws-lambda-java-events.version>3.11.0</aws-lambda-java-events.version>
         <aws-lambda-java-core.version>1.2.1</aws-lambda-java-core.version>
-        <gson.version>2.8.2</gson.version>
+        <gson.version>2.10.1</gson.version>
     </properties>
 
 </project>

aws-modules/aws-lambda-modules/shipping-tracker-lambda/ShippingFunction/pom.xml

@@ -31,15 +31,21 @@
             <version>${jackson-databind.version}</version>
         </dependency>
         <dependency>
-            <groupId>org.hibernate</groupId>
+            <groupId>org.hibernate.orm</groupId>
             <artifactId>hibernate-core</artifactId>
             <version>${hibernate.version}</version>
         </dependency>
         <dependency>
-            <groupId>org.hibernate</groupId>
+            <groupId>org.hibernate.orm</groupId>
             <artifactId>hibernate-hikaricp</artifactId>
             <version>${hibernate.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.zaxxer</groupId>
+            <artifactId>HikariCP</artifactId>
+            <version>${hikari.cp.version}</version>
+        </dependency>
+
         <dependency>
             <groupId>org.postgresql</groupId>
             <artifactId>postgresql</artifactId>
@@ -70,11 +76,12 @@
     <properties>
         <maven.compiler.source>11</maven.compiler.source>
         <maven.compiler.target>11</maven.compiler.target>
-        <hibernate.version>5.4.21.Final</hibernate.version>
+        <hibernate.version>6.4.2.Final</hibernate.version>
         <aws-lambda-java-core.version>1.2.0</aws-lambda-java-core.version>
         <aws-lambda-java-events.version>3.1.0</aws-lambda-java-events.version>
         <jackson-databind.version>2.11.2</jackson-databind.version>
         <postgresql.version>42.2.16</postgresql.version>
+        <hikari.cp.version>5.1.0</hikari.cp.version>
     </properties>
 
 </project>

aws-modules/aws-lambda-modules/shipping-tracker-lambda/ShippingFunction/src/main/java/com/baeldung/lambda/shipping/App.java

@@ -83,7 +83,7 @@ private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
     }
 
     private static SessionFactory createSessionFactory() {
-        Map<String, String> settings = new HashMap<>();
+        Map<String, Object> settings = new HashMap<>();
         settings.put(URL, System.getenv("DB_URL"));
         settings.put(DIALECT, "org.hibernate.dialect.PostgreSQLDialect");
         settings.put(DEFAULT_SCHEMA, "shipping");

aws-modules/aws-lambda-modules/shipping-tracker-lambda/ShippingFunction/src/main/java/com/baeldung/lambda/shipping/Checkin.java

@@ -1,7 +1,7 @@
 package com.baeldung.lambda.shipping;
 
-import javax.persistence.Column;
-import javax.persistence.Embeddable;
+import jakarta.persistence.Column;
+import jakarta.persistence.Embeddable;
 
 @Embeddable
 public class Checkin {

aws-modules/aws-lambda-modules/shipping-tracker-lambda/ShippingFunction/src/main/java/com/baeldung/lambda/shipping/Consignment.java

@@ -1,10 +1,10 @@
 package com.baeldung.lambda.shipping;
 
-import javax.persistence.*;
+import jakarta.persistence.*;
 import java.util.ArrayList;
 import java.util.List;
 
-import static javax.persistence.FetchType.EAGER;
+import static jakarta.persistence.FetchType.EAGER;
 
 @Entity(name = "consignment")
 @Table(name = "consignment")

aws-modules/aws-lambda-modules/shipping-tracker-lambda/ShippingFunction/src/main/java/com/baeldung/lambda/shipping/Item.java

@@ -1,7 +1,7 @@
 package com.baeldung.lambda.shipping;
 
-import javax.persistence.Column;
-import javax.persistence.Embeddable;
+import jakarta.persistence.Column;
+import jakarta.persistence.Embeddable;
 
 @Embeddable
 public class Item {

aws-modules/aws-miscellaneous/pom.xml

@@ -37,7 +37,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-dependency-plugin</artifactId>
-                <version>${maven-plugins-version}</version>
+                <version>${maven-dependency-plugin.version}</version>
                 <executions>
                     <execution>
                         <id>copy</id>
@@ -58,10 +58,7 @@
 
     <properties>
         <gson.version>2.10.1</gson.version>
-        <dynamodblocal.version>1.21.1</dynamodblocal.version>
-        <commons-codec-version>1.16.0</commons-codec-version>
-        <jets3t-version>0.9.4.0006L</jets3t-version>
-        <maven-plugins-version>3.1.1</maven-plugins-version>
+        <maven-dependency-plugin.version>3.1.1</maven-dependency-plugin.version>
     </properties>
 
 </project>

aws-modules/aws-reactive/pom.xml

@@ -27,7 +27,7 @@
             <dependency>
                 <groupId>software.amazon.awssdk</groupId>
                 <artifactId>bom</artifactId>
-                <version>${awssdk.version}</version>
+                <version>${aws-java-sdk-v2.version}</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
@@ -93,7 +93,6 @@
 
     <properties>
         <spring.version>2.2.1.RELEASE</spring.version>
-        <awssdk.version>2.17.283</awssdk.version>
         <reactor.version>3.6.0</reactor.version>
     </properties>
 

aws-modules/aws-s3/pom.xml

@@ -18,7 +18,7 @@
         <dependency>
             <groupId>software.amazon.awssdk</groupId>
             <artifactId>s3</artifactId>
-            <version>${aws.java.sdk.version}</version>
+            <version>${aws-java-sdk-v2.version}</version>
         </dependency>
         <dependency>
             <groupId>software.amazon.awssdk</groupId>
@@ -36,12 +36,12 @@
         <dependency>
             <groupId>org.lucee</groupId>
             <artifactId>jets3t</artifactId>
-            <version>${jets3t-version}</version>
+            <version>${jets3t.version}</version>
         </dependency>
         <dependency>
             <groupId>org.lucee</groupId>
             <artifactId>commons-codec</artifactId>
-            <version>${commons-codec-version}</version>
+            <version>${commons-codec.version}</version>
         </dependency>
         <!-- adobe s3mock -->
         <dependency>
@@ -67,10 +67,10 @@
 
     <properties>
         <aws.java.sdk.version>2.20.52</aws.java.sdk.version>
-        <commons-codec-version>1.10.L001</commons-codec-version>
-        <jets3t-version>0.9.4.0006L</jets3t-version>
         <com.adobe.testing.version>3.3.0</com.adobe.testing.version>
         <org.testcontainers.version>1.19.4</org.testcontainers.version>
+        <commons-codec.version>1.10.L001</commons-codec.version>
+        <jets3t.version>0.9.4.0014L</jets3t.version>
     </properties>
 
 </project>

aws-modules/pom.xml

@@ -33,7 +33,7 @@
 
     <properties>
         <aws-java-sdk.version>1.12.331</aws-java-sdk.version>
-        <aws-java-sdk-v2.version>2.20.147</aws-java-sdk-v2.version>
+        <aws-java-sdk-v2.version>2.24.9</aws-java-sdk-v2.version>
         <maven-shade-plugin.version>3.0.0</maven-shade-plugin.version>
     </properties>
 

core-groovy-modules/core-groovy-2/pom.xml

@@ -157,7 +157,7 @@
     <properties>
         <groovy-wslite.version>1.1.3</groovy-wslite.version>
         <assembly.plugin.version>3.4.2</assembly.plugin.version>
-        <compiler.plugin.version>3.8.1</compiler.plugin.version>
+        <compiler.plugin.version>3.12.1</compiler.plugin.version>
         <groovy.compiler.version>3.9.0</groovy.compiler.version>
         <groovy-eclipse-batch.version>3.0.9-03</groovy-eclipse-batch.version>
     </properties>

core-groovy-modules/core-groovy/src/test/groovy/com/baeldung/io/TraverseFileTreeUnitTest.groovy

@@ -1,61 +1,71 @@
 package com.baeldung.io
 
-import org.junit.Test
-
 import groovy.io.FileType
 import groovy.io.FileVisitResult
+import org.junit.Test
+
+import static org.junit.Assert.assertTrue
 
 class TraverseFileTreeUnitTest {
     @Test
     void whenUsingEachFile_filesAreListed() {
+        var files = []
         new File('src/main/resources').eachFile { file ->
-            println file.name
+            files.add(file.name)
         }
+        assertTrue(files.size() > 1)
     }
     
     @Test(expected = IllegalArgumentException)
     void whenUsingEachFileOnAFile_anErrorOccurs() {
+        var files = []
         new File('src/main/resources/ioInput.txt').eachFile { file ->
-            println file.name
+            files.add(file.name)
         }
     }
     
     @Test
     void whenUsingEachFileMatch_filesAreListed() {
+        var files = []
         new File('src/main/resources').eachFileMatch(~/io.*\.txt/) { file ->
-            println file.name
+            files.add(file.name)
         }
     }
-    
+
     @Test
     void whenUsingEachFileRecurse_thenFilesInSubfoldersAreListed() {
+        var files = []
         new File('src/main').eachFileRecurse(FileType.FILES) { file ->
-            println "$file.parent $file.name"
+            files.add("$file.parent $file.name")
         }
     }
-    
+
     @Test
     void whenUsingEachFileRecurse_thenDirsInSubfoldersAreListed() {
+        var files = []
         new File('src/main').eachFileRecurse(FileType.DIRECTORIES) { file ->
-            println "$file.parent $file.name"
+            files.add("$file.parent $file.name")
         }
     }
-    
+
     @Test
     void whenUsingEachDirRecurse_thenDirsAndSubDirsAreListed() {
+        var files = []
         new File('src/main').eachDirRecurse { dir ->
-            println "$dir.parent $dir.name"
+            files.add("$dir.parent $dir.name")
         }
     }
-    
+
     @Test
     void whenUsingTraverse_thenDirectoryIsTraversed() {
+        var files = []
         new File('src/main').traverse { file ->
             if (file.directory && file.name == 'groovy') {
                 FileVisitResult.SKIP_SUBTREE
             } else {
-                println "$file.parent - $file.name"
+                files.add("$file.parent - $file.name")
             }
         }
+        assertTrue(files.size() > 1)
     }
 }

core-groovy-modules/core-groovy/src/test/groovy/com/baeldung/stringtypes/DollarSlashyString.groovy

@@ -2,6 +2,8 @@ package groovy.com.baeldung.stringtypes
 
 import org.junit.Test
 
+import static org.junit.Assert.assertFalse
+
 class DollarSlashyString {
 
     @Test
@@ -19,6 +21,7 @@ class DollarSlashyString {
             - $/$$
         /$
 
-        print(dollarSlashy)
+        //print(dollarSlashy)
+        assertFalse(dollarSlashy.isEmpty())
     }
 }

core-java-modules/core-java-11-3/pom.xml

@@ -45,8 +45,7 @@
     <properties>
         <maven.compiler.source.version>11</maven.compiler.source.version>
         <maven.compiler.target.version>11</maven.compiler.target.version>
-        <jackson.version>2.16.0</jackson.version>
-        <gson.version>2.10</gson.version>
+        <gson.version>2.10.1</gson.version>
     </properties>
 
 </project>

core-java-modules/core-java-18/README.md

@@ -1,2 +1,3 @@
 ## Relevant Articles
 - [Deprecate Finalization in Java 18](https://www.baeldung.com/java-18-deprecate-finalization)
+- [Simple Web Server in Java 18](https://www.baeldung.com/simple-web-server-java-18)

core-java-modules/core-java-18/src/main/java/com/baeldung/simplewebserver/WebServer.java

@@ -0,0 +1,59 @@
+package com.baeldung.simplewebserver;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.nio.file.Path;
+import java.util.function.Predicate;
+
+import com.sun.net.httpserver.Filter;
+import com.sun.net.httpserver.Headers;
+import com.sun.net.httpserver.HttpHandler;
+import com.sun.net.httpserver.HttpHandlers;
+import com.sun.net.httpserver.HttpServer;
+import com.sun.net.httpserver.Request;
+import com.sun.net.httpserver.SimpleFileServer;
+
+public class WebServer {
+
+    private final InetSocketAddress address = new InetSocketAddress(8080);
+    private final Path path = Path.of("/");
+
+    public static void main(String[] args) {
+        WebServer webServer = new WebServer();
+        HttpServer server = webServer.createWithHandler401Response();
+        server.start();
+    }
+
+    private HttpServer createBasic() {
+        return SimpleFileServer.createFileServer(address, path, SimpleFileServer.OutputLevel.VERBOSE);
+    }
+
+    private HttpServer createWithHandler() throws IOException {
+        HttpServer server = SimpleFileServer.createFileServer(address, path, SimpleFileServer.OutputLevel.VERBOSE);
+        HttpHandler handler = SimpleFileServer.createFileHandler(Path.of("/Users"));
+        server.createContext("/test", handler);
+        return server;
+    }
+
+    private HttpServer createWithHandler401Response() {
+        Predicate<Request> findAllowedPath = r -> r.getRequestURI()
+          .getPath()
+          .equals("/test/allowed");
+
+        HttpHandler allowedResponse = HttpHandlers.of(200, Headers.of("Allow", "GET"), "Welcome");
+        HttpHandler deniedResponse = HttpHandlers.of(401, Headers.of("Deny", "GET"), "Denied");
+
+        HttpHandler handler = HttpHandlers.handleOrElse(findAllowedPath, allowedResponse, deniedResponse);
+
+        HttpServer server = SimpleFileServer.createFileServer(address, path, SimpleFileServer.OutputLevel.VERBOSE);
+        server.createContext("/test", handler);
+        return server;
+    }
+
+    private HttpServer createWithFilter() throws IOException {
+        Filter filter = SimpleFileServer.createOutputFilter(System.out, SimpleFileServer.OutputLevel.INFO);
+        HttpHandler handler = SimpleFileServer.createFileHandler(Path.of("/Users"));
+        return HttpServer.create(new InetSocketAddress(8080), 10, "/test", handler, filter);
+    }
+
+}

core-java-modules/core-java-19/src/main/java/com/baeldung/vectors/VectorAPIExamples.java

@@ -63,7 +63,7 @@ public class VectorAPIExamples {
     public float[] scalarNormOfTwoArrays(float[] arr1, float[] arr2) {
         float[] finalResult = new float[arr1.length];
         for (int i = 0; i < arr1.length; i++) {
-            finalResult[i] = (arr1[i] * arr1[i] + arr2[i] * arr2[i]) * -1.0f;
+            finalResult[i] = (float) Math.sqrt(arr1[i] * arr1[i] + arr2[i] * arr2[i]);
         }
         return finalResult;
     }
@@ -77,13 +77,13 @@ public class VectorAPIExamples {
             var vb = FloatVector.fromArray(PREFERRED_SPECIES, arr2, i);
             var vc = va.mul(va)
               .add(vb.mul(vb))
-              .neg();
+              .sqrt();
             vc.intoArray(finalResult, i);
         }
 
         // tail cleanup
         for (; i < arr1.length; i++) {
-            finalResult[i] = (arr1[i] * arr1[i] + arr2[i] * arr2[i]) * -1.0f;
+            finalResult[i] = (float) Math.sqrt(arr1[i] * arr1[i] + arr2[i] * arr2[i]);
         }
         return finalResult;
     }

core-java-modules/core-java-19/src/test/java/com/baeldung/vectors/VectorAPIUnitTest.java

@@ -28,7 +28,7 @@ public class VectorAPIUnitTest {
     public void whenTwoValuesProvided_thenComputeScalarNorm() {
         float[] arr1 = { 1, 2.3f };
         float[] arr2 = { 1.3f, 2.0f };
-        float[] result = { -2.6899998f, -9.29f };
+        float[] result = { 1.6401219f, 3.047950f };
         Assertions.assertArrayEquals(result, vector.scalarNormOfTwoArrays(arr1, arr2));
     }
 
@@ -36,7 +36,7 @@ public class VectorAPIUnitTest {
     public void whenTwoValuesProvided_thenComputeVectorNorm() {
         float[] arr1 = { 1, 2.3f };
         float[] arr2 = { 1.3f, 2.0f };
-        float[] result = { -2.6899998f, -9.29f };
+        float[] result = { 1.6401219f, 3.047950f };
         Assertions.assertArrayEquals(result, vector.vectorNormalForm(arr1, arr2));
     }
 

core-java-modules/core-java-21/README.md

@@ -3,3 +3,4 @@
 - [String Templates in Java 21](https://www.baeldung.com/java-21-string-templates)
 - [Unnamed Classes and Instance Main Methods in Java 21](https://www.baeldung.com/java-21-unnamed-class-instance-main)
 - [Unnamed Patterns and Variables in Java 21](https://www.baeldung.com/java-unnamed-patterns-variables)
+- [JFR View Command in Java 21](https://www.baeldung.com/java-flight-recorder-view)

core-java-modules/core-java-8-datetime-2/README.md

@@ -10,4 +10,7 @@
 - [Representing Furthest Possible Date in Java](https://www.baeldung.com/java-date-represent-max)
 - [Retrieving Unix Time in Java](https://www.baeldung.com/java-retrieve-unix-time)
 - [Calculate Months Between Two Dates in Java](https://www.baeldung.com/java-months-difference-two-dates)
+- [Format LocalDate to ISO 8601 With T and Z](https://www.baeldung.com/java-format-localdate-iso-8601-t-z)
+- [Check if Two Date Ranges Overlap](https://www.baeldung.com/java-check-two-date-ranges-overlap)
+- [Difference between ZoneOffset.UTC and ZoneId.of(“UTC”)](https://www.baeldung.com/java-zoneoffset-utc-zoneid-of)
 - [[<-- Prev]](/core-java-modules/core-java-datetime-java8-1)

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

@@ -12,3 +12,4 @@ This module contains articles about arrays conversion in Java
 - [Convert an ArrayList of String to a String Array in Java](https://www.baeldung.com/java-convert-string-arraylist-array)
 - [Convert Char Array to Int Array in Java](https://www.baeldung.com/java-convert-char-int-array)
 - [How to Convert Byte Array to Char Array](https://www.baeldung.com/java-convert-byte-array-char)
+- [Convert byte[] to Byte[] and Vice Versa in Java](https://www.baeldung.com/java-byte-array-wrapper-primitive-type-convert)

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

@@ -10,3 +10,4 @@ This module contains complete guides about arrays in Java
 - [Creating a Generic Array in Java](https://www.baeldung.com/java-generic-array)
 - [Maximum Size of Java Arrays](https://www.baeldung.com/java-arrays-max-size)
 - [Merge Two Arrays and Remove Duplicates in Java](https://www.baeldung.com/java-merge-two-arrays-delete-duplicates)
+- [Print a Java 2D Array](https://www.baeldung.com/java-2d-array-print)

core-java-modules/core-java-arrays-guides/pom.xml

@@ -7,10 +7,6 @@
     <name>core-java-arrays-guides</name>
     <packaging>jar</packaging>
 
-    <properties>
-        <system-stubs.jupiter.version>2.1.5</system-stubs.jupiter.version>
-    </properties>
-
     <parent>
         <artifactId>core-java-modules</artifactId>
         <groupId>com.baeldung.core-java-modules</groupId>
@@ -34,7 +30,10 @@
             <version>${system-stubs.jupiter.version}</version>
             <scope>test</scope>
         </dependency>
-
     </dependencies>
 
+    <properties>
+        <system-stubs.jupiter.version>2.1.5</system-stubs.jupiter.version>
+    </properties>
+
 </project>

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

@@ -1,2 +1,4 @@
 ## Relevant Articles
 - [Find the Middle Element of an Array in Java](https://www.baeldung.com/java-array-middle-item)
+- [Find the Equilibrium Indexes of an Array in Java](https://www.baeldung.com/java-equilibrium-index-array)
+- [Moves Zeros to the End of an Array in Java](https://www.baeldung.com/java-array-sort-move-zeros-end)

core-java-modules/core-java-arrays-operations-advanced-2/src/main/java/com/baeldung/equilibriumindex/EquilibriumIndexFinder.java

@@ -0,0 +1,24 @@
+package com.baeldung.equilibriumindex;
+
+import java.util.ArrayList;
+import java.util.List;
+
+class EquilibriumIndexFinder {
+    
+    List<Integer> findEquilibriumIndexes(int[] array) {
+        int[] partialSums = new int[array.length + 1];
+        partialSums[0] = 0;
+        for (int i = 0; i < array.length; i++) {
+            partialSums[i+1] = partialSums[i] + array[i]; 
+        }
+        
+        List<Integer> equilibriumIndexes = new ArrayList<Integer>();
+        for (int i = 0; i < array.length; i++) {
+            if (partialSums[i] == (partialSums[array.length] - (partialSums[i+1]))) {
+                equilibriumIndexes.add(i);
+            }
+        }
+        return equilibriumIndexes;
+    }
+
+}

core-java-modules/core-java-arrays-operations-advanced-2/src/test/java/com/baeldung/equilibriumindex/EquilibriumIndexFinderUnitTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.equilibriumindex;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+class EquilibriumIndexFinderUnitTest {
+    
+    @Test
+    void givenArrayHasEquilibriumIndexes_whenFindEquilibriumIndexes_thenListAllEquilibriumIndexes() {
+        int[] array = {1, -3, 0, 4, -5, 4, 0, 1, -2, -1};
+        assertThat(new EquilibriumIndexFinder().findEquilibriumIndexes(array)).containsExactly(1, 4, 9);
+    }
+   
+    @Test
+    void givenArrayWithoutEquilibriumIndexes_whenFindEquilibriumIndexes_thenEmptyList() {
+        int[] array = {1, 2, 3};
+        assertThat(new EquilibriumIndexFinder().findEquilibriumIndexes(array)).isEmpty();
+    }
+   
+    @Test
+    void givenArrayWithOneElement_whenFindEquilibriumIndexes_thenListFirstIndex() {
+        int[] array = {5};
+        assertThat(new EquilibriumIndexFinder().findEquilibriumIndexes(array)).containsExactly(0);
+    }
+
+}

core-java-modules/core-java-arrays-operations-advanced-2/src/test/java/com/baeldung/movezerototheend/MoveZeroesToTheEndOfAnArrayUnitTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.movezerototheend;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+public class MoveZeroesToTheEndOfAnArrayUnitTest {
+    private static final int[] EXPECTED = new int[] { 42, 2, 3, 4, 0, 0 };
+
+    @Test
+    void whenCreatingANewArrayAndCopyingValues_thenGetTheExpectedResult() {
+        int[] array = new int[] { 42, 2, 0, 3, 4, 0 };
+        int[] result = new int[array.length];
+        int idx = 0;
+        for (int n : array) {
+            if (n != 0) {
+                result[idx++] = n;
+            }
+        }
+        assertArrayEquals(EXPECTED, result);
+    }
+
+    @Test
+    void whenMovingZeroInTheOriginalArray_thenGetTheExpectedResult() {
+        int[] array = new int[] { 42, 2, 0, 3, 4, 0 };
+        int idx = 0;
+        for (int n : array) {
+            if (n != 0) {
+                array[idx++] = n;
+            }
+        }
+        while (idx < array.length) {
+            array[idx++] = 0;
+        }
+        assertArrayEquals(EXPECTED, array);
+    }
+}

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

@@ -6,3 +6,4 @@ This module contains articles about Java Character Class
 - [Character#isAlphabetic vs. Character#isLetter](https://www.baeldung.com/java-character-isletter-isalphabetic)
 - [Difference Between Java’s “char” and “String”](https://www.baeldung.com/java-char-vs-string)
 - [Increment Character in Java](https://www.baeldung.com/java-char-sequence)
+- [Creating Unicode Character From Its Code Point Hex String](https://www.baeldung.com/java-unicode-character-from-code-point-hex-string)

core-java-modules/core-java-char/src/test/java/com/baeldung/unicodechar/UnicodeCharFromCodePointHexStringUnitTest.java

@@ -0,0 +1,70 @@
+package com.baeldung.unicodechar;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class UnicodeCharFromCodePointHexStringUnitTest {
+    private static final String U_CHECK = "✅"; // U+2705
+    private static final String U_STRONG = "强"; // U+5F3A
+
+
+    @Test
+    void whenEscapeUAndNumberInString_thenGetExpectedUnicodeStr() {
+        String check = "\u2705";
+        assertEquals(U_CHECK, check);
+
+        String strong = "\u5F3A";
+        assertEquals(U_STRONG, strong);
+
+        // "A" U+0041
+        assertEquals("A", "\u0041");
+    }
+
+
+    @Test
+    void whenConcatUAndNumberAsString_thenDoNotGetExpectedUnicodeStr() {
+        String check = "\\u" + "2705";
+        assertEquals("\\u2705", check);
+
+        String strong = "\\u" + "5F3A";
+        assertEquals("\\u5F3A", strong);
+    }
+
+
+    @Test
+    void whenCastHexCodePointToCharAndConvertCharToString_thenGetExpectedUnicodeStr() {
+
+        int codePoint = Integer.parseInt("2705", 16); //Decimal int: 9989
+        char[] checkChar = Character.toChars(codePoint);
+        String check = String.valueOf(checkChar);
+        assertEquals(U_CHECK, check);
+
+        // For Java 11 and later versions
+        // assertEquals(U_CHECK, Character.toString(codePoint));
+
+        codePoint = Integer.parseInt("5F3A", 16); //Decimal int: 24378
+        char[] strongChar = Character.toChars(codePoint);
+        String strong = String.valueOf(strongChar);
+        assertEquals(U_STRONG, strong);
+
+        // For Java 11 and later versions
+        // assertEquals(U_STRONG, Character.toString(codePoint));
+    }
+
+    String stringFromCodePointHex(String codePointHex) {
+        int codePoint = Integer.parseInt(codePointHex, 16);
+
+        // For Java 11 and later versions: return Character.toString(codePoint)
+
+        char[] chars = Character.toChars(codePoint);
+        return String.valueOf(chars);
+    }
+
+    @Test
+    void whenUsingstringFromCodePointHex_thenGetExpectedUnicodeStr() {
+        assertEquals("A", stringFromCodePointHex("0041"));
+        assertEquals(U_CHECK, stringFromCodePointHex("2705"));
+        assertEquals(U_STRONG, stringFromCodePointHex("5F3A"));
+    }
+}

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

@@ -13,4 +13,5 @@
 - [Time Complexity of Java Collections Sort in Java](https://www.baeldung.com/java-time-complexity-collections-sort)
 - [Check if List Contains at Least One Enum](https://www.baeldung.com/java-list-check-enum-presence)
 - [Comparison of for Loops and Iterators](https://www.baeldung.com/java-for-loops-vs-iterators)
+- [PriorityQueue iterator() Method in Java](https://www.baeldung.com/java-priorityqueue-iterator)
 - More articles: [[<-- prev]](/core-java-modules/core-java-collections-4)

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

@@ -5,18 +5,6 @@
     <modelVersion>4.0.0</modelVersion>
     <artifactId>core-java-collections-5</artifactId>
     <name>core-java-collections-5</name>
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <configuration>
-                    <source>9</source>
-                    <target>9</target>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
     <packaging>jar</packaging>
 
     <parent>
@@ -61,6 +49,19 @@
         </dependency>
     </dependencies>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>9</source>
+                    <target>9</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
     <properties>
         <junit.version>5.9.2</junit.version>
         <roaringbitmap.version>0.9.38</roaringbitmap.version>

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

@@ -22,7 +22,7 @@
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
-            <version>31.1-jre</version>
+            <version>${guava.version}</version>
             <scope>test</scope>
         </dependency>
     </dependencies>

core-java-modules/core-java-collections-list-5/pom.xml

@@ -55,13 +55,11 @@
             <version>${org.json.version}</version>
             <scope>test</scope>
         </dependency>
-
     </dependencies>
 
     <properties>
         <jmh.version>1.21</jmh.version>
         <gson.version>2.10.1</gson.version>
-        <jackson.version>2.16.0</jackson.version>
         <org.json.version>20230618</org.json.version>
     </properties>
 </project>

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

@@ -3,3 +3,4 @@
 - [Removing the Last Node in a Linked List](https://www.baeldung.com/java-linked-list-remove-last-element)
 - [Call a Method on Each Element of a List in Java](https://www.baeldung.com/java-call-method-each-list-item)
 - [Sorting One List Based on Another List in Java](https://www.baeldung.com/java-sorting-one-list-using-another)
+- [Reset ListIterator to First Element of the List in Java](https://www.baeldung.com/java-reset-listiterator)

core-java-modules/core-java-collections-list-6/pom.xml

@@ -29,4 +29,4 @@
     <properties>
         <vavr.version>0.10.4</vavr.version>
     </properties>
-</project>
+</project>

core-java-modules/core-java-collections-list-6/src/test/java/com/baeldung/modifyandprint/ModifyAndPrintListElementsUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.modifyandprint;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.collect.Lists;
+
+public class ModifyAndPrintListElementsUnitTest {
+
+    private final Logger log = LoggerFactory.getLogger(ModifyAndPrintListElementsUnitTest.class);
+
+    @Test
+    void whenPrintingInForEach_thenListIsPrinted() {
+        List<String> theList = Lists.newArrayList("Kai", "Liam", "Eric", "Kevin");
+        theList.forEach(element -> log.info(element));
+    }
+
+    @Test
+    void whenUsingModifyAndPrintingSeparately_thenListIsModifiedAndPrinted() {
+        List<String> theList = Lists.newArrayList("Kai", "Liam", "Eric", "Kevin");
+        theList.replaceAll(element -> element.toUpperCase());
+        theList.forEach(element -> log.info(element));
+        assertEquals(List.of("KAI", "LIAM", "ERIC", "KEVIN"), theList);
+    }
+
+    @Test
+    void whenPrintingInMap_thenStreamIsModifiedAndPrinted() {
+        List<String> theList = List.of("Kai", "Liam", "Eric", "Kevin");
+        List<String> newList = theList.stream()
+            .map(element -> {
+                String newElement = element.toUpperCase();
+                log.info(newElement);
+                return newElement;
+            })
+            .collect(Collectors.toList());
+        assertEquals(List.of("KAI", "LIAM", "ERIC", "KEVIN"), newList);
+    }
+
+    @Test
+    void whenPrintingInPeek_thenStreamIsModifiedAndPrinted() {
+        List<String> theList = List.of("Kai", "Liam", "Eric", "Kevin");
+        List<String> newList = theList.stream()
+            .map(element -> element.toUpperCase())
+            .peek(element-> log.info(element))
+            .collect(Collectors.toList());
+        assertEquals(List.of("KAI", "LIAM", "ERIC", "KEVIN"), newList);
+    }
+}

core-java-modules/core-java-collections-maps-6/pom.xml

@@ -27,7 +27,7 @@
         <dependency>
             <groupId>com.google.code.gson</groupId>
             <artifactId>gson</artifactId>
-            <version>2.8.9</version>
+            <version>2.10.1</version>
         </dependency>
         <dependency>
             <groupId>org.json</groupId>

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

@@ -5,6 +5,8 @@
 - [How to Get First or Last Entry From a LinkedHashMap in Java](https://www.baeldung.com/java-linkedhashmap-first-last-key-value-pair)
 - [How to Write and Read a File with a Java HashMap](https://www.baeldung.com/java-hashmap-write-read-file)
 - [Limiting the Max Size of a HashMap in Java](https://www.baeldung.com/java-hashmap-size-bound)
-- [How to Sort LinkedHashMap By Values in Java](https://www.baeldung.com/java-sort-linkedhashmap-using-values)
+- [How to Sort LinkedHashMap by Values in Java](https://www.baeldung.com/java-sort-linkedhashmap-using-values)
 - [How to Increment a Map Value in Java](https://www.baeldung.com/java-increment-map-value)
+- [Collect Stream of entrySet() to a LinkedHashMap](https://www.baeldung.com/java-linkedhashmap-entryset-stream)
+- [How to Pretty-Print a Map in Java](https://www.baeldung.com/java-map-pretty-print)
 - More articles: [[<-- prev]](/core-java-modules/core-java-collections-maps-6)

core-java-modules/core-java-collections-maps-7/pom.xml

@@ -32,17 +32,22 @@
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
-            <version>32.1.2-jre</version>
+            <version>${guava.version}</version>
         </dependency>
         <dependency>
             <groupId>org.openjdk.jmh</groupId>
             <artifactId>jmh-core</artifactId>
-            <version>1.37</version>
+            <version>${jmh.version}</version>
         </dependency>
         <dependency>
             <groupId>org.openjdk.jmh</groupId>
             <artifactId>jmh-generator-annprocess</artifactId>
-            <version>1.37</version>
+            <version>${jmh.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections.version}</version>
         </dependency>
     </dependencies>
 
@@ -63,6 +68,9 @@
     <properties>
         <gson.version>2.10.1</gson.version>
         <csv.version>1.5</csv.version>
+        <guava.version>32.1.2-jre</guava.version>
+        <jmh.version>1.37</jmh.version>
+        <commons-collections.version>4.4</commons-collections.version>
     </properties>
 
 </project>

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

@@ -0,0 +1,111 @@
+package com.baeldung.map.entrysettolinkedhashmap;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class EntrySetToLinkedHashMapUnitTest {
+
+    private Map<Integer, String> map;
+
+    @Test
+    void givenMap_whenUsingCollectorsGroupingBy_thenCollectToLinkedHashMap() {
+        Map<String, Set<String>> countryToCities = Map.of("Paris", "France", "Nice", "France", "Madrid", "Spain")
+            .entrySet()
+            .stream()
+            .collect(Collectors.groupingBy(Map.Entry::getValue, LinkedHashMap::new, Collectors.mapping(Map.Entry::getKey, Collectors.toSet())));
+
+        assertThat(countryToCities).isExactlyInstanceOf(LinkedHashMap.class)
+            .containsOnly(entry("France", Set.of("Paris", "Nice")), entry("Spain", Set.of("Madrid")));
+    }
+
+    @Test
+    void givenMap_whenUsingCollectorsToMap_thenCollectAndConvertToLinkedHashMap() {
+        Map<Integer, String> result = new LinkedHashMap<>(map.entrySet()
+            .stream()
+            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue)));
+
+        assertThat(result).isExactlyInstanceOf(LinkedHashMap.class)
+            .containsOnly(entry(1, "value 1"), entry(2, "value 2"));
+    }
+
+    @Test
+    void givenMap_whenUsingCollectorsToMap_thenCollectToLinkedHashMap() {
+        Map<Integer, String> result = map.entrySet()
+            .stream()
+            .collect(Collectors.toMap(
+                Map.Entry::getKey, Map.Entry::getValue,
+                (e1, e2) -> {
+                    throw new RuntimeException();
+                }, 
+                LinkedHashMap::new));
+
+        assertThat(result).isExactlyInstanceOf(LinkedHashMap.class)
+            .containsOnly(entry(1, "value 1"), entry(2, "value 2"));
+    }
+
+    @Test
+    void givenMap_whenUsingLinkedHashMapConstructor_thenObtainLinkedHashMap() {
+        Map<Integer, String> result = new LinkedHashMap<>(map);
+
+        assertThat(result).isExactlyInstanceOf(LinkedHashMap.class)
+            .containsOnly(entry(1, "value 1"), entry(2, "value 2"));
+    }
+
+    @Test
+    void givenMap_whenUsingPutWithForLoop_thenInsertIntoLinkedHashMap() {
+        Map<Integer, String> result = new LinkedHashMap<>();
+
+        for (Map.Entry<Integer, String> entry : map.entrySet()) {
+            result.put(entry.getKey(), entry.getValue());
+        }
+
+        assertThat(result).isExactlyInstanceOf(LinkedHashMap.class)
+            .containsOnly(entry(1, "value 1"), entry(2, "value 2"));
+    }
+
+    @Test
+    void givenMap_whenUsingPutWithMapForEach_thenInsertIntoLinkedHashMap() {
+        Map<Integer, String> result = new LinkedHashMap<>();
+
+        map.forEach((k, v) -> result.put(k, v));
+
+        assertThat(result).isExactlyInstanceOf(LinkedHashMap.class)
+            .containsOnly(entry(1, "value 1"), entry(2, "value 2"));
+    }
+
+    @Test
+    void givenMap_whenUsingPutWithSetForEach_thenInsertIntoLinkedHashMap() {
+        Map<Integer, String> result = new LinkedHashMap<>();
+
+        map.entrySet()
+            .forEach(entry -> result.put(entry.getKey(), entry.getValue()));
+
+        assertThat(result).isExactlyInstanceOf(LinkedHashMap.class)
+            .containsOnly(entry(1, "value 1"), entry(2, "value 2"));
+    }
+
+    @Test
+    void givenMap_whenUsingPutWithStreamForEach_thenInsertIntoLinkedHashMapp() {
+        Map<Integer, String> result = new LinkedHashMap<>();
+
+        map.entrySet()
+            .stream()
+            .forEach(entry -> result.put(entry.getKey(), entry.getValue()));
+
+        assertThat(result).isExactlyInstanceOf(LinkedHashMap.class)
+            .containsOnly(entry(1, "value 1"), entry(2, "value 2"));
+    }
+
+    @BeforeEach
+    void init() {
+        map = Map.of(1, "value 1", 2, "value 2");
+    }
+}

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

@@ -0,0 +1,202 @@
+package com.baeldung.map.prettyprintmap;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.base.Joiner;
+import com.google.gson.GsonBuilder;
+import org.apache.commons.collections4.MapUtils;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.PrintStream;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+class PrettyPrintMapUnitTest {
+
+    private static final Map<String, Object> MAP;
+
+    static {
+        // using LinkedHashMap to keep insertion order, helpful in assertions
+        MAP = new LinkedHashMap<>();
+        MAP.put("one", 1);
+        MAP.put("two", 2);
+
+        Map<String, Integer> innerMap = new LinkedHashMap<>();
+        innerMap.put("ten", 10);
+        innerMap.put("eleven", 11);
+
+        MAP.put("inner", innerMap);
+    }
+
+    @Test
+    void givenMap_whenToString_thenOneLine() {
+        String result = MAP.toString();
+
+        String expected = "{one=1, two=2, inner={ten=10, eleven=11}}";
+        Assertions.assertThat(result).isEqualTo(expected);
+    }
+
+    @Test
+    void givenMap_whenSimpleForEachLoop_thenPrettyPrintWithoutNested() {
+        StringBuilder result = new StringBuilder();
+
+        for (Map.Entry<?, ?> entry : MAP.entrySet()) {
+            result.append(String.format("%-15s : %s%n", entry.getKey(), entry.getValue()));
+        }
+
+        String expected =
+            "one             : 1\n" +
+            "two             : 2\n" +
+            "inner           : {ten=10, eleven=11}\n";
+        Assertions.assertThat(result.toString()).isEqualToIgnoringNewLines(expected);
+    }
+
+    @Test
+    void givenMap_whenRecursionForEachLoop_thenPrettyPrint() {
+        String result = printMap(0, MAP);
+
+        String expected =
+            "one             : 1\n" +
+            "two             : 2\n" +
+            "inner           :\n" +
+            "    ten             : 10\n" +
+            "    eleven          : 11\n";
+        Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
+    }
+
+    @Test
+    void givenMap_whenStream_thenPrettyPrintWithoutNested() {
+        StringBuilder result = new StringBuilder();
+
+        MAP.forEach((k, v) -> result.append(String.format("%-15s : %s%n", k, v)));
+
+        String expected =
+            "one             : 1\n" +
+            "two             : 2\n" +
+            "inner           : {ten=10, eleven=11}\n";
+        Assertions.assertThat(result.toString()).isEqualToIgnoringNewLines(expected);
+    }
+
+    @Test
+    void givenMap_whenExtendedStream_thenPrettyPrintWithoutNested() {
+        String result = MAP.entrySet().stream()
+            .map(entry -> String.format("%-15s : %s", entry.getKey(), entry.getValue()))
+            .collect(Collectors.joining("\n"));
+
+        String expected =
+            "one             : 1\n" +
+            "two             : 2\n" +
+            "inner           : {ten=10, eleven=11}\n";
+        Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
+    }
+    @Test
+    void givenMap_whenJackson_thenPrettyPrint() throws JsonProcessingException {
+        String result = new ObjectMapper().writerWithDefaultPrettyPrinter().writeValueAsString(MAP);
+
+        String expected =
+            "{\n" +
+            "  \"one\" : 1,\n" +
+            "  \"two\" : 2,\n" +
+            "  \"inner\" : {\n" +
+            "    \"ten\" : 10,\n" +
+            "    \"eleven\" : 11\n" +
+            "  }\n" +
+            "}";
+        Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
+    }
+
+    @Test
+    void givenMap_whenGson_thenPrettyPrint() {
+        String result = new GsonBuilder().setPrettyPrinting().create().toJson(MAP);
+
+        String expected =
+            "{\n" +
+            "  \"one\": 1,\n" +
+            "  \"two\": 2,\n" +
+            "  \"inner\": {\n" +
+            "    \"ten\": 10,\n" +
+            "    \"eleven\": 11\n" +
+            "  }\n" +
+            "}";
+        Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
+    }
+
+    @Test
+    void givenMap_whenApacheCommonsCollectionsDebugPrint_thenPrettyPrintWithClassNames() throws IOException {
+        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
+             PrintStream ps = new PrintStream(baos)) {
+
+            MapUtils.debugPrint(ps, "map", MAP);
+            String result = baos.toString();
+
+            String expected =
+                "map = \n" +
+                "{\n" +
+                "    one = 1 java.lang.Integer\n" +
+                "    two = 2 java.lang.Integer\n" +
+                "    inner = \n" +
+                "    {\n" +
+                "        ten = 10 java.lang.Integer\n" +
+                "        eleven = 11 java.lang.Integer\n" +
+                "    } java.util.LinkedHashMap\n" +
+                "} java.util.LinkedHashMap\n";
+            Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
+        }
+    }
+
+    @Test
+    void givenMap_whenApacheCommonsCollectionsVerbosePrint_thenPrettyPrint() throws IOException {
+        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
+             PrintStream ps = new PrintStream(baos)) {
+
+            MapUtils.verbosePrint(ps, "map", MAP);
+            String result = baos.toString();
+
+            String expected =
+                "map = \n" +
+                "{\n" +
+                "    one = 1\n" +
+                "    two = 2\n" +
+                "    inner = \n" +
+                "    {\n" +
+                "        ten = 10\n" +
+                "        eleven = 11\n" +
+                "    }\n" +
+                "}\n";
+            Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
+        }
+    }
+
+    @Test
+    void givenMap_whenGuavaJoiner_thenPrettyPrintWithoutNested() {
+        String result = Joiner.on(",\n").withKeyValueSeparator("=").join(MAP);
+
+        String expected =
+            "one=1,\n" +
+            "two=2,\n" +
+            "inner={ten=10, eleven=11}";
+        Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
+    }
+
+    private static String printMap(int leftPadding, Map<?, ?> map) {
+        StringBuilder ret = new StringBuilder();
+
+        for (Map.Entry<?, ?> entry : map.entrySet()) {
+            if (entry.getValue() instanceof Map) {
+                ret.append(String.format("%-15s :%n", entry.getKey()));
+                ret.append(printMap(leftPadding + 4, (Map<?, ?>) entry.getValue()));
+            }
+            else {
+                ret.append(String.format("%" + (leftPadding > 0 ? leftPadding : "") + "s" // adding padding
+                        + "%-15s : %s%n",
+                    "", entry.getKey(), entry.getValue()));
+            }
+        }
+        return ret.toString();
+    }
+
+}

core-java-modules/core-java-collections-set-2/pom.xml

@@ -35,7 +35,7 @@
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
-            <version>32.1.1-jre</version>
+            <version>${guava.version}</version>
         </dependency>
     </dependencies>
 

core-java-modules/core-java-collections-set/pom.xml

@@ -41,7 +41,7 @@
     </build>
 
     <properties>
-        <gson.version>2.8.5</gson.version>
+        <gson.version>2.10.1</gson.version>
     </properties>
 
 </project>

core-java-modules/core-java-collections/src/test/java/com/baeldung/hashtable/HashtableUnitTest.java

@@ -60,14 +60,15 @@ public class HashtableUnitTest {
         table.put(new Word("dog"), "another animal");
 
         Iterator<Word> it = table.keySet().iterator();
-        System.out.println("iterator created");
+        // System.out.println("iterator created");
 
         table.remove(new Word("dog"));
-        System.out.println("element removed");
+        // System.out.println("element removed");
 
         while (it.hasNext()) {
             Word key = it.next();
-            System.out.println(table.get(key));
+            // System.out.println(table.get(key));
+            assertNotNull(table.get(key));
         }
     }
 
@@ -85,12 +86,13 @@ public class HashtableUnitTest {
         table.put(new Word("8"), "eight");
 
         Enumeration<Word> enumKey = table.keys();
-        System.out.println("Enumeration created");
+        // System.out.println("Enumeration created");
         table.remove(new Word("1"));
-        System.out.println("element removed");
+        // System.out.println("element removed");
         while (enumKey.hasMoreElements()) {
             Word key = enumKey.nextElement();
-            System.out.println(table.get(key));
+            // System.out.println(table.get(key));
+            assertNotNull(table.get(key));
         }
     }
 
@@ -110,7 +112,8 @@ public class HashtableUnitTest {
         Iterator<Map.Entry<Word, String>> it = table.entrySet().iterator();
         while (it.hasNext()) {
             Map.Entry<Word, String> entry = it.next();
-            System.out.println(entry.getValue());
+            // System.out.println(entry.getValue());
+            assertNotNull(entry.getValue());
         }
     }
 

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

@@ -8,3 +8,6 @@
 - [How to Check if All Runnables Are Done](https://www.baeldung.com/java-runnables-check-status)
 - [Parallelize for Loop in Java](https://www.baeldung.com/java-for-loop-parallel)
 - [How to Effectively Unit Test CompletableFuture](https://www.baeldung.com/java-completablefuture-unit-test)
+- [How to Collect All Results and Handle Exceptions With CompletableFuture in a Loop](https://www.baeldung.com/java-completablefuture-collect-results-handle-exceptions)
+- [CompletableFuture runAsync() vs. supplyAsync() in Java](https://www.baeldung.com/java-completablefuture-runasync-supplyasync)
+- [Difference Between thenApply() and thenApplyAsync() in CompletableFuture](https://www.baeldung.com/java-completablefuture-thenapply-thenapplyasync)

core-java-modules/core-java-concurrency-2/src/main/java/com/baeldung/runvssupply/RunAndSupplyCompare.java

@@ -0,0 +1,79 @@
+package com.baeldung.runvssupply;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+
+public class RunAndSupplyCompare {
+
+    public static void main(String args[]) throws ExecutionException, InterruptedException {
+        chainingOperationCompare();
+    }
+
+    public static void inputAndReturnCompare() throws ExecutionException, InterruptedException {
+        CompletableFuture<Void> runAsyncFuture = CompletableFuture.runAsync(() -> {
+            // Perform non-result producing task
+            System.out.println("Task executed asynchronously");
+        });
+
+        CompletableFuture<String> supplyAsyncFuture = CompletableFuture.supplyAsync(() -> {
+            // Perform result-producing task
+            return "Result of the asynchronous computation";
+        });
+        // Get the result later
+        String result = supplyAsyncFuture.get();
+        System.out.println("Result: " + result);
+    }
+
+    public static void exceptionHandlingCompare() {
+        CompletableFuture<Void> runAsyncFuture = CompletableFuture.runAsync(() -> {
+            // Task that may throw an exception
+            throw new RuntimeException("Exception occurred in asynchronous task");
+        });
+        try {
+            runAsyncFuture.get();
+            // Exception will be thrown here
+        } catch (ExecutionException ex) {
+            Throwable cause = ex.getCause();
+            System.out.println("Exception caught: " + cause.getMessage());
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
+
+        CompletableFuture<Object> supplyAsyncFuture = CompletableFuture.supplyAsync(() -> {
+                // Task that may throw an exception
+                throw new RuntimeException("Exception occurred in asynchronous task");
+            })
+            .exceptionally(ex -> {
+                // Exception handling logic
+                return "Default value";
+            });
+
+        Object result = supplyAsyncFuture.join();
+        // Get the result or default value
+        System.out.println("Result: " + result);
+    }
+
+    public static void chainingOperationCompare() {
+        CompletableFuture<Void> runAsyncFuture = CompletableFuture.runAsync(() -> {
+            // Perform non-result producing task
+            System.out.println("Task executed asynchronously");
+        });
+        runAsyncFuture.thenRun(() -> {
+            // Execute another task after the completion of runAsync()
+            System.out.println("Another task executed after runAsync() completes");
+        });
+
+        CompletableFuture<String> supplyAsyncFuture = CompletableFuture.supplyAsync(() -> {
+            // Perform result-producing task
+            return "Result of the asynchronous computation";
+        });
+        supplyAsyncFuture.thenApply(result -> {
+                // Transform the result
+                return result.toUpperCase();
+            })
+            .thenAccept(transformedResult -> {
+                // Consume the transformed result
+                System.out.println("Transformed Result: " + transformedResult);
+            });
+    }
+}

core-java-modules/core-java-concurrency-2/src/test/java/com/baeldung/concurrent/applyvsapplyasync/ThenApplyAndThenApplyAsyncUnitTest.java

@@ -0,0 +1,91 @@
+package com.baeldung.concurrent.applyvsapplyasync;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class ThenApplyAndThenApplyAsyncUnitTest {
+
+    @Test
+    public void givenCompletableFuture_whenUsingThenApply_thenResultIsAsExpected() {
+        CompletableFuture<Integer> future = CompletableFuture.supplyAsync(() -> 5);
+        CompletableFuture<String> thenApplyResultFuture = future.thenApply(num -> "Result: " + num);
+
+        String thenApplyResult = thenApplyResultFuture.join();
+        assertEquals("Result: 5", thenApplyResult);
+    }
+
+    @Test
+    public void givenCompletableFuture_whenUsingThenApplyAsync_thenResultIsAsExpected() {
+        CompletableFuture<Integer> future = CompletableFuture.supplyAsync(() -> 5);
+        CompletableFuture<String> thenApplyAsyncResultFuture = future.thenApplyAsync(num -> "Result: " + num);
+
+        String thenApplyAsyncResult = thenApplyAsyncResultFuture.join();
+        assertEquals("Result: 5", thenApplyAsyncResult);
+    }
+
+    @Test
+    public void givenCompletableFuture_whenUsingThenApply_thenExceptionIsPropagated() {
+        CompletableFuture<Integer> future = CompletableFuture.supplyAsync(() -> 5);
+        CompletableFuture<String> resultFuture = future.thenApply(num -> "Result: " + num / 0);
+        assertThrows(CompletionException.class, () -> resultFuture.join());
+    }
+
+    @Test
+    public void givenCompletableFuture_whenUsingThenApply_thenExceptionIsHandledAsExpected() {
+        CompletableFuture<Integer> future = CompletableFuture.supplyAsync(() -> 5);
+        CompletableFuture<String> resultFuture = future.thenApply(num -> "Result: " + num / 0);
+        try {
+            // Accessing the result
+            String result = resultFuture.join();
+            assertEquals("Result: 5", result);
+        } catch (CompletionException e) {
+            assertEquals("java.lang.ArithmeticException: / by zero", e.getMessage());
+            System.err.println("Exception caught: " + e.getMessage());
+        }
+    }
+
+    @Test
+    public void givenCompletableFuture_whenUsingThenApplyAsync_thenExceptionIsHandledAsExpected() {
+        CompletableFuture<Integer> future = CompletableFuture.supplyAsync(() -> 5);
+        CompletableFuture<String> thenApplyAsyncResultFuture = future.thenApplyAsync(num -> "Result: " + num / 0);
+
+        String result = thenApplyAsyncResultFuture.handle((res, error) -> {
+                if (error != null) {
+                    // Handle the error appropriately, e.g., return a default value
+                    return "Error occurred";
+                } else {
+                    return res;
+                }
+            })
+            .join(); // Now join() won't throw the exception
+        assertEquals("Error occurred", result);
+    }
+
+    @Test
+    public void givenCompletableFutureWithExecutor_whenUsingThenApplyAsync_thenThreadExecutesAsExpected() {
+        ExecutorService customExecutor = Executors.newFixedThreadPool(4);
+
+        CompletableFuture<Integer> future = CompletableFuture.supplyAsync(() -> {
+            try {
+                Thread.sleep(2000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+            return 5;
+        }, customExecutor);
+
+        CompletableFuture<String> resultFuture = future.thenApplyAsync(num -> "Result: " + num, customExecutor);
+
+        String result = resultFuture.join();
+        assertEquals("Result: 5", result);
+
+        customExecutor.shutdown();
+    }
+}

core-java-modules/core-java-concurrency-2/src/test/java/com/baeldung/concurrent/completablefuture/CombiningCompletableFuturesUnitTest.java

@@ -0,0 +1,90 @@
+package com.baeldung.concurrent.completablefuture;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class CombiningCompletableFuturesUnitTest {
+
+    private final Logger logger = mock(Logger.class);
+
+    private static Stream<Arguments> clientData() {
+        return Stream.of(
+            Arguments.of(List.of("Good Resource"), 1, 0),
+            Arguments.of(List.of("Bad Resource"), 0, 1),
+            Arguments.of(List.of("Good Resource", "Bad Resource"), 1, 1),
+            Arguments.of(List.of("Good Resource", "Bad Resource", "Good Resource", "Bad Resource", "Good Resource"), 3, 2)
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("clientData")
+    public void givenMicroserviceClient_whenMultipleCreateResource_thenCombineResults(List<String> inputs, int successCount, int errorCount) {
+        MicroserviceClient mockMicroservice = mock(MicroserviceClient.class);
+        // Return an identifier of 123 on "Good Resource"
+        when(mockMicroservice.createResource("Good Resource"))
+            .thenReturn(CompletableFuture.completedFuture(123L));
+        // Throw an exception on "Bad Resource"
+        when(mockMicroservice.createResource("Bad Resource"))
+            .thenReturn(CompletableFuture.failedFuture(new IllegalArgumentException("Bad Resource")));
+
+        // Given a list of CompletableFutures from our microservice calls...
+        List<CompletableFuture<Long>> clientCalls = new ArrayList<>();
+        for (String resource : inputs) {
+            clientCalls.add(mockMicroservice.createResource(resource));
+        }
+
+        // When all CompletableFutures are completed (exceptionally or otherwise)...
+        Map<Boolean, List<Long>> resultsByValidity = clientCalls.stream()
+            .map(this::handleFuture)
+            .collect(Collectors.partitioningBy(resourceId -> resourceId != -1L));
+
+        // Then the returned resource identifiers should match what is expected...
+        List<Long> validResults = resultsByValidity.getOrDefault(true, List.of());
+        assertThat(validResults.size()).isEqualTo(successCount);
+
+        // And the logger mock should be called once for each exception with the expected error message
+        List<Long> invalidResults = resultsByValidity.getOrDefault(false, List.of());
+        assertThat(invalidResults.size()).isEqualTo(errorCount);
+        verify(logger, times(errorCount))
+            .error(eq("Encountered error: java.lang.IllegalArgumentException: Bad Resource"));
+    }
+
+    /**
+     * Completes the given CompletableFuture, handling any exceptions that are thrown.
+     * @param future the CompletableFuture to complete.
+     * @return the resource identifier (-1 if the request failed).
+     */
+    private Long handleFuture(CompletableFuture<Long> future) {
+        return future
+            .exceptionally(this::handleError)
+            .join();
+    }
+
+    private Long handleError(Throwable throwable) {
+        logger.error("Encountered error: " + throwable);
+        return -1L;
+    }
+
+    interface MicroserviceClient {
+        CompletableFuture<Long> createResource(String resourceName);
+    }
+
+    interface Logger {
+        void error(String message);
+    }
+}

core-java-modules/core-java-concurrency-advanced-5/README.md

@@ -2,3 +2,4 @@
 ### Relevant Articles:
 - [Why wait() Requires Synchronization?](https://www.baeldung.com/java-wait-necessary-synchronization)
 - [Working with Exceptions in Java CompletableFuture](https://www.baeldung.com/java-exceptions-completablefuture)
+- [CountDownLatch vs. Semaphore](https://www.baeldung.com/java-countdownlatch-vs-semaphore)

core-java-modules/core-java-concurrency-advanced-5/src/main/java/com/baeldung/countdownlatchvssemaphore/CountDownLatchDemo.java

@@ -0,0 +1,33 @@
+package com.baeldung.countdownlatchvssemaphore;
+
+import java.util.concurrent.CountDownLatch;
+
+public class CountDownLatchDemo {
+
+    public static void main(String[] args) throws InterruptedException {
+        // Create a CountDownLatch with an initial count equal to the number of tasks to be completed
+        int numberOfTasks = 3;
+        CountDownLatch latch = new CountDownLatch(numberOfTasks);
+
+        // Simulate completion of tasks by worker threads
+        for (int i = 1; i <= numberOfTasks; i++) {
+            new Thread(() -> {
+                System.out.println("Task completed by Thread " + Thread.currentThread()
+                    .getId());
+
+                // Decrement the latch count to signal completion of a task
+                latch.countDown();
+            }).start();
+        }
+
+        // Main thread waits until all tasks are completed
+        latch.await();
+        System.out.println("All tasks completed. Main thread proceeds.");
+
+        // Attempting to reset will have no effect
+        latch.countDown();
+        // Latch is already at zero, await() returns immediately
+        latch.await(); // This line won't block
+        System.out.println("Latch is already at zero and cannot be reset.");
+    }
+}

core-java-modules/core-java-concurrency-advanced-5/src/main/java/com/baeldung/countdownlatchvssemaphore/SemaphoreDemo.java

@@ -0,0 +1,42 @@
+package com.baeldung.countdownlatchvssemaphore;
+
+import java.util.concurrent.Semaphore;
+
+public class SemaphoreDemo {
+
+    public static void main(String[] args) {
+        // Create a Semaphore with a fixed number of permits
+        int NUM_PERMITS = 3;
+        Semaphore semaphore = new Semaphore(NUM_PERMITS);
+
+        // Simulate resource access by worker threads
+        for (int i = 1; i <= 5; i++) {
+            new Thread(() -> {
+                try {
+                    // Acquire a permit to access the resource
+                    semaphore.acquire();
+                    System.out.println("Thread " + Thread.currentThread().getId() + " accessing resource.");
+
+                    // Simulate resource usage
+                    Thread.sleep(2000);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                } finally {
+                    // Release the permit after resource access is complete
+                    semaphore.release();
+                }
+            }).start();
+        }
+
+        // Simulate resetting the Semaphore by releasing additional permits after a delay
+        try {
+            Thread.sleep(5000);
+
+            // Resetting the semaphore permits to the initial count
+            semaphore.release(NUM_PERMITS);
+            System.out.println("Semaphore permits reset to initial count.");
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+}

core-java-modules/core-java-concurrency-simple/src/test/resources/logback.xml

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

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

@@ -8,3 +8,5 @@
 - [System.console() vs. System.out](https://www.baeldung.com/java-system-console-vs-system-out)
 - [How to Log to the Console in Color](https://www.baeldung.com/java-log-console-in-color)
 - [Create Table Using ASCII in a Console in Java](https://www.baeldung.com/java-console-ascii-make-table)
+- [Printing Message on Console without Using main() Method in Java](https://www.baeldung.com/java-no-main-print-message-console)
+- [Guide to System.in.read()](https://www.baeldung.com/java-system-in-read)

core-java-modules/core-java-console/src/main/java/com/baeldung/systemin/SystemInRead.java

@@ -0,0 +1,45 @@
+package com.baeldung.systemin;
+
+import java.io.IOException;
+
+class SystemInRead {
+    static void readSingleCharacter() {
+        System.out.println("Enter a character:");
+        try {
+            int input = System.in.read();
+            System.out.println((char) input);
+        }
+        catch (IOException e) {
+            System.err.println("Error reading input: " + e.getMessage());
+        }
+    }
+    static void readMultipleCharacters() {
+        System.out.println("Enter characters (Press 'Enter' to quit):");
+        try {
+            int input;
+            while ((input = System.in.read()) != '\n') {
+                System.out.print((char) input);
+            }
+        } catch (IOException e) {
+            System.err.println("Error reading input: " + e.getMessage());
+        }
+    }
+
+    static void readWithParameters() {
+        try {
+            byte[] byteArray = new byte[5];
+            int bytesRead;
+            int totalBytesRead = 0;
+
+            while ((bytesRead = System.in.read(byteArray, 0, byteArray.length)) != -1) {
+                System.out.print("Data read: " + new String(byteArray, 0, bytesRead));
+                totalBytesRead += bytesRead;
+            }
+
+            System.out.println("\nBytes Read: " + totalBytesRead);
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}

core-java-modules/core-java-console/src/test/java/com/baeldung/systemin/SystemInReadUnitTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.systemin;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+
+import org.junit.jupiter.api.Test;
+
+public class SystemInReadUnitTest {
+    @Test
+    void givenUserInput_whenUsingReadMultipleCharacters_thenRead() {
+        System.setIn(new ByteArrayInputStream("Hello\n".getBytes()));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outputStream));
+        SystemInRead.readMultipleCharacters();
+
+        assertEquals("Enter characters (Press 'Enter' to quit):\n" + "Hello", outputStream.toString().trim());
+    }
+
+    @Test
+    void givenUserInput_whenUsingReadSingleCharacter_thenRead() {
+        System.setIn(new ByteArrayInputStream("A".getBytes()));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outputStream));
+        SystemInRead.readSingleCharacter();
+
+        assertEquals("Enter a character:\nA", outputStream.toString().trim());
+    }
+
+    @Test
+    void givenUserInput_whenUsingReadWithParameters_thenRead() {
+        System.setIn(new ByteArrayInputStream("ABC".getBytes()));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outputStream));
+        SystemInRead.readWithParameters();
+
+        assertEquals("Data read: ABC\n" + "Bytes Read: 3", outputStream.toString().trim());
+    }
+}

core-java-modules/core-java-date-operations-4/README.md

@@ -2,5 +2,6 @@
 This module contains articles about date operations in Java.
 
 ### Relevant Articles:
-
-
+- [Calculate Number of Weekdays Between Two Dates in Java](https://www.baeldung.com/java-count-weekdays-between-two-dates)
+- [Convert Long to Date in Java](https://www.baeldung.com/java-long-date-conversion)
+- [Convert Date to Unix Timestamp in Java](https://www.baeldung.com/java-convert-date-unix-timestamp)

core-java-modules/core-java-date-operations-4/pom.xml

@@ -5,6 +5,7 @@
     <modelVersion>4.0.0</modelVersion>
     <artifactId>core-java-date-operations-4</artifactId>
     <name>core-java-date-operations-4</name>
+
     <build>
         <plugins>
             <plugin>
@@ -39,7 +40,7 @@
     </dependencies>
 
     <properties>
-        <joda-time.version>2.12.5</joda-time.version>
+        <joda-time.version>2.12.6</joda-time.version>
     </properties>
 
 </project>

core-java-modules/core-java-date-operations-4/src/test/java/com/baeldung/datetounixtimestamp/DateToUnixTimeStampUnitTest.java

@@ -0,0 +1,65 @@
+package com.baeldung.datetounixtimestamp;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneOffset;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+import java.util.TimeZone;
+
+import org.joda.time.DateTime;
+import org.junit.jupiter.api.Test;
+
+class DateToUnixTimeStampUnitTest {
+
+    @Test
+    void givenDate_whenUsingInstantClass_thenConvertToUnixTimeStamp() {
+        Instant givenDate = Instant.parse("2020-09-08T12:16:40Z");
+
+        assertEquals(1599567400L, givenDate.getEpochSecond());
+    }
+
+    @Test
+    void givenDate_whenUsingLocalDateTimeClass_thenConvertToUnixTimeStamp() {
+        LocalDateTime givenDate = LocalDateTime.of(2023, 10, 19, 22, 45);
+
+        assertEquals(1697755500L, givenDate.toEpochSecond(ZoneOffset.UTC));
+    }
+
+    @Test
+    void givenDate_whenUsingDateClass_thenConvertToUnixTimeStamp() throws ParseException {
+        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+        dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
+        Date givenDate = dateFormat.parse("2023-10-15 22:00:00");
+
+        assertEquals(1697407200L, givenDate.getTime() / 1000);
+    }
+
+    @Test
+    void givenDate_whenUsingCalendarClass_thenConvertToUnixTimeStamp() {
+        Calendar calendar = new GregorianCalendar(2023, Calendar.OCTOBER, 17);
+        calendar.setTimeZone(TimeZone.getTimeZone("UTC"));
+
+        assertEquals(1697500800L, calendar.getTimeInMillis() / 1000);
+    }
+
+    @Test
+    void givenDate_whenUsingJodaTimeInstantClass_thenConvertToUnixTimeStamp() {
+        org.joda.time.Instant givenDate = org.joda.time.Instant.parse("2020-09-08T12:16:40Z");
+
+        assertEquals(1599567400L, givenDate.getMillis() / 1000);
+    }
+
+    @Test
+    void givenDate_whenUsingJodaTimeDateTimeClass_thenConvertToUnixTimeStamp() {
+        DateTime givenDate = new DateTime("2020-09-09T12:16:40Z");
+
+        assertEquals(1599653800L, givenDate.getMillis() / 1000);
+    }
+
+}

core-java-modules/core-java-date-operations-4/src/test/java/com/baeldung/longtodate/LongToDateUnitTest.java

@@ -0,0 +1,74 @@
+package com.baeldung.longtodate;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.time.LocalDate;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.TimeZone;
+
+import org.joda.time.DateTimeZone;
+import org.joda.time.Instant;
+import org.junit.jupiter.api.Test;
+
+class LongToDateUnitTest {
+
+    @Test
+    void givenLongValue_whenUsingInstantClass_thenConvert() {
+        Instant expectedDate = Instant.parse("2020-09-08T12:16:40Z");
+        long seconds = 1599567400L;
+
+        Instant date = Instant.ofEpochSecond(seconds);
+
+        assertEquals(expectedDate, date);
+    }
+
+    @Test
+    void givenLongValue_whenUsingLocalDateClass_thenConvert() {
+        LocalDate expectedDate = LocalDate.of(2023, 10, 17);
+        long epochDay = 19647L;
+
+        LocalDate date = LocalDate.ofEpochDay(epochDay);
+
+        assertEquals(expectedDate, date);
+    }
+
+    @Test
+    void givenLongValue_whenUsingDateClass_thenConvert() throws ParseException {
+        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+        dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
+        Date expectedDate = dateFormat.parse("2023-07-15 22:00:00");
+        long milliseconds = 1689458400000L;
+
+        Date date = new Date(milliseconds);
+
+        assertEquals(expectedDate, date);
+    }
+
+    @Test
+    void givenLongValue_whenUsingCalendarClass_thenConvert() throws ParseException {
+        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+        dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
+        Date expectedDate = dateFormat.parse("2023-07-15 22:00:00");
+        long milliseconds = 1689458400000L;
+
+        Calendar calendar = Calendar.getInstance();
+        calendar.setTimeZone(TimeZone.getTimeZone("UTC"));
+        calendar.setTimeInMillis(milliseconds);
+
+        assertEquals(expectedDate, calendar.getTime());
+    }
+
+    @Test
+    void givenLongValue_whenUsingJodaTimeLocalDateClass_thenConvert() {
+        org.joda.time.LocalDate expectedDate = new org.joda.time.LocalDate(2023, 7, 15);
+        long milliseconds = 1689458400000L;
+
+        org.joda.time.LocalDate date = new org.joda.time.LocalDate(milliseconds, DateTimeZone.UTC);
+
+        assertEquals(expectedDate, date);
+    }
+
+}

core-java-modules/core-java-datetime-conversion-2/README.md

@@ -0,0 +1,7 @@
+## Java Date/time conversion Cookbooks and Examples
+
+This module contains articles about converting between Java date and time objects.
+
+### Relevant Articles: 
+- [Convert Gregorian to Hijri Date in Java](https://www.baeldung.com/java-date-gregorian-hijri-conversion)
+- [Convert String Date to XMLGregorianCalendar in Java](https://www.baeldung.com/java-string-date-xmlgregoriancalendar-conversion)

core-java-modules/core-java-datetime-conversion-2/pom.xml

@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>core-java-datetime-conversion-2</artifactId>
+    <name>core-java-datetime-conversion-2</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>joda-time</groupId>
+            <artifactId>joda-time</artifactId>
+            <version>${joda-time.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.github.msarhan</groupId>
+            <artifactId>ummalqura-calendar</artifactId>
+            <version>${ummalqura-calendar.version}</version>
+        </dependency>
+
+    </dependencies>
+
+    <build>
+        <finalName>core-java-datetime-conversion-2</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <joda-time.version>2.12.5</joda-time.version>
+        <ummalqura-calendar.version>2.0.2</ummalqura-calendar.version>
+    </properties>
+
+</project>

core-java-modules/core-java-datetime-conversion-2/src/main/java/com/baeldung/stringdatetoxmlgregoriancalendar/StringDateToXMLGregorianCalendarConverter.java

@@ -0,0 +1,42 @@
+package com.baeldung.stringdatetoxmlgregoriancalendar;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.time.LocalDate;
+import java.util.Date;
+import java.util.GregorianCalendar;
+
+import javax.xml.datatype.DatatypeConfigurationException;
+import javax.xml.datatype.DatatypeFactory;
+import javax.xml.datatype.XMLGregorianCalendar;
+
+import org.joda.time.DateTime;
+import org.joda.time.format.DateTimeFormat;
+
+public class StringDateToXMLGregorianCalendarConverter {
+    public static XMLGregorianCalendar usingDatatypeFactoryForDate(String dateAsString) throws DatatypeConfigurationException {
+        return DatatypeFactory.newInstance().newXMLGregorianCalendar(dateAsString);
+    }
+
+    public static XMLGregorianCalendar usingLocalDate(String dateAsString) throws DatatypeConfigurationException {
+        LocalDate localDate = LocalDate.parse(dateAsString);
+        return DatatypeFactory.newInstance().newXMLGregorianCalendar(localDate.toString());
+    }
+
+    public static XMLGregorianCalendar usingSimpleDateFormat(String dateTimeAsString) throws DatatypeConfigurationException, ParseException {
+        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
+        Date date = simpleDateFormat.parse(dateTimeAsString);
+        return DatatypeFactory.newInstance().newXMLGregorianCalendar(simpleDateFormat.format(date));
+    }
+
+    public static XMLGregorianCalendar usingGregorianCalendar(String dateTimeAsString) throws DatatypeConfigurationException, ParseException {
+        GregorianCalendar calendar = new GregorianCalendar();
+        calendar.setTime(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss").parse(dateTimeAsString));
+        return DatatypeFactory.newInstance().newXMLGregorianCalendar(calendar);
+    }
+
+    public static XMLGregorianCalendar usingJodaTime(String dateTimeAsString) throws DatatypeConfigurationException {
+        DateTime dateTime = DateTime.parse(dateTimeAsString, DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss"));
+        return DatatypeFactory.newInstance().newXMLGregorianCalendar(dateTime.toGregorianCalendar());
+    }
+}

core-java-modules/core-java-datetime-conversion-2/src/test/java/com/baeldung/stringdatetoxmlgregoriancalendar/StringDateToXMLGregorianCalendarConverterUnitTest.java

@@ -0,0 +1,63 @@
+package com.baeldung.stringdatetoxmlgregoriancalendar;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.text.ParseException;
+import javax.xml.datatype.DatatypeConfigurationException;
+import javax.xml.datatype.XMLGregorianCalendar;
+
+import org.junit.jupiter.api.Test;
+
+public class StringDateToXMLGregorianCalendarConverterUnitTest {
+    private static final String dateAsString = "2014-04-24";
+    private static final String dateTimeAsString = "2014-04-24T15:45:30";
+
+    @Test
+    void givenStringDate_whenUsingDatatypeFactory_thenConvertToXMLGregorianCalendar() throws DatatypeConfigurationException {
+        XMLGregorianCalendar xmlGregorianCalendar = StringDateToXMLGregorianCalendarConverter.usingDatatypeFactoryForDate(dateAsString);
+        assertEquals(24,xmlGregorianCalendar.getDay());
+        assertEquals(4,xmlGregorianCalendar.getMonth());
+        assertEquals(2014,xmlGregorianCalendar.getYear());
+    }
+
+    @Test
+    void givenStringDateTime_whenUsingApacheCommonsLang3_thenConvertToXMLGregorianCalendar() throws DatatypeConfigurationException {
+        XMLGregorianCalendar xmlGregorianCalendar = StringDateToXMLGregorianCalendarConverter.usingLocalDate(dateAsString);
+        assertEquals(24,xmlGregorianCalendar.getDay());
+        assertEquals(4,xmlGregorianCalendar.getMonth());
+        assertEquals(2014,xmlGregorianCalendar.getYear());
+    }
+
+    @Test
+    void givenStringDateTime_whenUsingSimpleDateFormat_thenConvertToXMLGregorianCalendar() throws DatatypeConfigurationException, ParseException {
+        XMLGregorianCalendar xmlGregorianCalendar = StringDateToXMLGregorianCalendarConverter.usingSimpleDateFormat(dateTimeAsString);
+        assertEquals(24,xmlGregorianCalendar.getDay());
+        assertEquals(4,xmlGregorianCalendar.getMonth());
+        assertEquals(2014,xmlGregorianCalendar.getYear());
+        assertEquals(15,xmlGregorianCalendar.getHour());
+        assertEquals(45,xmlGregorianCalendar.getMinute());
+        assertEquals(30,xmlGregorianCalendar.getSecond());
+    }
+
+    @Test
+    void givenStringDateTime_whenUsingGregorianCalendar_thenConvertToXMLGregorianCalendar() throws DatatypeConfigurationException, ParseException {
+        XMLGregorianCalendar xmlGregorianCalendar = StringDateToXMLGregorianCalendarConverter.usingGregorianCalendar(dateTimeAsString);
+        assertEquals(24,xmlGregorianCalendar.getDay());
+        assertEquals(4,xmlGregorianCalendar.getMonth());
+        assertEquals(2014,xmlGregorianCalendar.getYear());
+        assertEquals(15,xmlGregorianCalendar.getHour());
+        assertEquals(45,xmlGregorianCalendar.getMinute());
+        assertEquals(30,xmlGregorianCalendar.getSecond());
+    }
+
+    @Test
+     void givenStringDateTime_whenUsingJodaTime_thenConvertToXMLGregorianCalendar() throws DatatypeConfigurationException {
+        XMLGregorianCalendar xmlGregorianCalendar = StringDateToXMLGregorianCalendarConverter.usingJodaTime(dateTimeAsString);
+        assertEquals(24,xmlGregorianCalendar.getDay());
+        assertEquals(4,xmlGregorianCalendar.getMonth());
+        assertEquals(2014,xmlGregorianCalendar.getYear());
+        assertEquals(15,xmlGregorianCalendar.getHour());
+        assertEquals(45,xmlGregorianCalendar.getMinute());
+        assertEquals(30,xmlGregorianCalendar.getSecond());
+    }
+}

core-java-modules/core-java-datetime-conversion/pom.xml

@@ -4,7 +4,6 @@
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <artifactId>core-java-datetime-conversion</artifactId>
-    <version>${project.parent.version}</version>
     <name>core-java-datetime-conversion</name>
     <packaging>jar</packaging>
 
@@ -25,12 +24,6 @@
             <artifactId>commons-lang3</artifactId>
             <version>${commons-lang3.version}</version>
         </dependency>
-        <dependency>
-            <groupId>com.github.msarhan</groupId>
-            <artifactId>ummalqura-calendar</artifactId>
-            <version>${ummalqura-calendar.version}</version>
-        </dependency>
-
     </dependencies>
 
     <build>
@@ -51,7 +44,6 @@
 
     <properties>
         <joda-time.version>2.12.5</joda-time.version>
-        <ummalqura-calendar.version>2.0.2</ummalqura-calendar.version>
     </properties>
 
 </project>

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

@@ -5,3 +5,4 @@ This module contains articles about parsing and formatting Java date and time ob
 ### Relevant Articles: 
 - [Convert String to Instant](https://www.baeldung.com/java-string-to-instant)
 - [Sort Date Strings in Java](https://www.baeldung.com/java-sort-date-strings)
+- [Using Current Time as Filename in Java](https://www.baeldung.com/java-current-time-filename)

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

@@ -6,3 +6,4 @@
 - [Java 8 Predicate Chain](https://www.baeldung.com/java-predicate-chain)
 - [Use Cases for Static Methods in Java](https://www.baeldung.com/java-static-methods-use-cases)
 - [TriFunction Interface in Java](https://www.baeldung.com/java-trifunction)
+- [Lazy Field Initialization with Lambdas](https://www.baeldung.com/java-lambda-lazy-field-initialization)

core-java-modules/core-java-functional/src/main/java/com/baeldung/functional/Currying.java

@@ -4,7 +4,7 @@ import java.util.function.Function;
 
 public class Currying {
 
-    private static Function<Double, Function<Double, Double>> weight = mass -> gravity -> mass * gravity;
+    private static Function<Double, Function<Double, Double>> weight = gravity -> mass -> mass * gravity;
 
     private static Function<Double, Double> weightOnEarth = weight.apply(9.81);