Merge branch 'eugenp:master' into master

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 +6,5 @@
 - [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)
 - 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-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-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

@@ -1,4 +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 {

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/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-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-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-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-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

@@ -7,4 +7,5 @@
 - [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 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)
 - 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/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 +8,4 @@
 - [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)

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

@@ -9,3 +9,4 @@
 - [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

@@ -3,4 +3,5 @@ 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/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-datetime-conversion-2/README.md

@@ -3,4 +3,5 @@
 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

@@ -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-2</artifactId>
-    <version>${project.parent.version}</version>
     <name>core-java-datetime-conversion-2</name>
     <packaging>jar</packaging>
 

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>
 

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);
 

core-java-modules/core-java-httpclient/src/test/resources/logback.xml

@@ -0,0 +1,16 @@
+<?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="org.eclipse.jetty.server.handler" level="WARN"/>
+    <logger name="org.mockserver.log" level="WARN"/>
+</configuration>

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

@@ -8,5 +8,6 @@ This module contains articles about core Java input and output (IO)
 - [Difference Between ZipFile and ZipInputStream in Java](https://www.baeldung.com/java-zipfile-vs-zipinputstream)
 - [How to Write Strings to OutputStream in Java](https://www.baeldung.com/java-write-string-outputstream)
 - [Read a File and Split It Into Multiple Files in Java](https://www.baeldung.com/java-read-file-split-into-several)
+- [Read and Write Files in Java Using Separate Threads](https://www.baeldung.com/java-read-write-files-different-threads)
 - [[<-- Prev]](/core-java-modules/core-java-io-4)
 

core-java-modules/core-java-io-5/file.txt

@@ -0,0 +1 @@
+Hello, world!

core-java-modules/core-java-io-5/src/main/java/com/baeldung/readwritethread/ReadWriteBlockingQueue.java

@@ -0,0 +1,85 @@
+package com.baeldung.readwritethread;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+public class ReadWriteBlockingQueue {
+
+    public static void main(String[] args) throws InterruptedException {
+
+        BlockingQueue<String> queue = new LinkedBlockingQueue<>();
+        String readFileName = "src/main/resources/read_file.txt";
+        String writeFileName = "src/main/resources/write_file.txt";
+
+        Thread producerThread = new Thread(new FileProducer(queue, readFileName));
+        Thread consumerThread1 = new Thread(new FileConsumer(queue, writeFileName));
+
+        producerThread.start();
+        Thread.sleep(100); // Give producer a head start
+        consumerThread1.start();
+        try {
+            producerThread.join();
+            consumerThread1.join();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+
+    }
+}
+
+class FileProducer implements Runnable {
+
+    private final BlockingQueue<String> queue;
+    private final String inputFileName;
+
+    public FileProducer(BlockingQueue<String> queue, String inputFileName) {
+        this.queue = queue;
+        this.inputFileName = inputFileName;
+    }
+
+    @Override
+    public void run() {
+        try (BufferedReader reader = new BufferedReader(new FileReader(inputFileName))) {
+            String line;
+            while ((line = reader.readLine()) != null) {
+                queue.offer(line);
+                System.out.println("Producer added line: " + line);
+                System.out.println("Queue size: " + queue.size());
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}
+
+class FileConsumer implements Runnable {
+
+    private final BlockingQueue<String> queue;
+    private final String outputFileName;
+
+    public FileConsumer(BlockingQueue queue, String outputFileName) {
+        this.queue = queue;
+        this.outputFileName = outputFileName;
+    }
+
+    @Override
+    public void run() {
+        try (BufferedWriter writer = new BufferedWriter(new FileWriter(outputFileName))) {
+            String line;
+            while ((line = queue.poll()) != null) {
+                writer.write(line);
+                writer.newLine();
+                System.out.println(Thread.currentThread()
+                    .getId() + " - Consumer processed line: " + line);
+                System.out.println("Queue size: " + queue.size());
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}

core-java-modules/core-java-io-5/src/main/java/com/baeldung/readwritethread/ReadWriteThread.java

@@ -0,0 +1,55 @@
+package com.baeldung.readwritethread;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+
+public class ReadWriteThread {
+
+    public static void readFile(String filePath) {
+        Thread thread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                try (BufferedReader bufferedReader = new BufferedReader(new FileReader(filePath))) {
+                    String line;
+                    while ((line = bufferedReader.readLine()) != null) {
+                        System.out.println(line);
+                    }
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        });
+        thread.start();
+    }
+
+    public static void writeFile(String filePath, String content) {
+        Thread thread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                try (FileWriter fileWriter = new FileWriter(filePath)) {
+                    fileWriter.write("Hello, world!");
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        });
+        thread.start();
+    }
+
+    public static void main(String[] args) {
+        String file = "src/main/resources/text.txt";
+
+        writeFile(file, "Hello, world!");
+
+        readFile(file);
+
+        // Sleep for a while to allow the threads to complete
+        try {
+            Thread.sleep(1000);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+}

core-java-modules/core-java-io-5/src/main/resources/read_file.txt

@@ -0,0 +1,5 @@
+Hello,
+Baeldung!
+Nice to meet you!
+My name is
+Wynn.

core-java-modules/core-java-io-5/src/main/resources/text.txt

@@ -0,0 +1 @@
+Hello, world!

core-java-modules/core-java-io-5/src/main/resources/write_file.txt

@@ -0,0 +1,5 @@
+Hello,
+Baeldung!
+Nice to meet you!
+My name is
+Wynn.

core-java-modules/core-java-io-apis-2/pom.xml

@@ -82,6 +82,7 @@
             <scope>test</scope>
         </dependency>
     </dependencies>
+
     <build>
         <finalName>core-java-io-apis-2</finalName>
         <resources>
@@ -91,6 +92,7 @@
             </resource>
         </resources>
     </build>
+
     <properties>
         <junit-jupiter-version>5.9.3</junit-jupiter-version>
     </properties>

core-java-modules/core-java-io-apis-2/src/test/java/com/baeldung/readinputcharbychar/ReadInputCharByCharUnitTest.java

@@ -51,9 +51,10 @@ public class ReadInputCharByCharUnitTest {
         System.setIn(inputStream);
 
         try (Scanner scanner = new Scanner(System.in)) {
-            char[] result = scanner.next().toCharArray();
-
-            assertArrayEquals("TestInput".toCharArray(), result);
+            if (scanner.hasNext()) {
+                char[] result = scanner.next().toCharArray();
+                assertArrayEquals("TestInput".toCharArray(), result);
+            }
         }
     }
 }

core-java-modules/core-java-jpms/service-loader-api-pattern/pom.xml

@@ -37,7 +37,7 @@
     </build>
 
     <properties>
-        <compiler.plugin.version>3.8.0</compiler.plugin.version>
+        <compiler.plugin.version>3.12.1</compiler.plugin.version>
         <source.version>11</source.version>
         <target.version>11</target.version>
     </properties>

core-java-modules/core-java-jpms/service-provider-factory-pattern/pom.xml

@@ -37,7 +37,7 @@
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <compiler.plugin.version>3.8.0</compiler.plugin.version>
+        <compiler.plugin.version>3.12.1</compiler.plugin.version>
         <source.version>11</source.version>
         <target.version>11</target.version>
     </properties>

core-java-modules/core-java-lang-6/README.md

@@ -14,3 +14,4 @@ This module contains articles about core features in the Java language
 - [Static Final Variables in Java](https://www.baeldung.com/java-static-final-variables)
 - [What Is the Error: “Non-static method cannot be referenced from a static context”?](https://www.baeldung.com/java-non-static-method-cannot-be-referenced-from-a-static-context)
 - [Recursively Sum the Integers in an Array](https://www.baeldung.com/java-recursive-sum-integer-array)
+- [Set an Environment Variable at Runtime in Java](https://www.baeldung.com/java-set-environment-variable-runtime)

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

@@ -3,14 +3,14 @@
     xmlns="http://maven.apache.org/POM/4.0.0"
     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-lang-6</artifactId>
+
     <parent>
         <groupId>com.baeldung.core-java-modules</groupId>
         <artifactId>core-java-modules</artifactId>
         <version>0.0.1-SNAPSHOT</version>
     </parent>
 
-    <artifactId>core-java-lang-6</artifactId>
-
     <dependencies>
         <!-- https://mvnrepository.com/artifact/org.mapstruct/mapstruct -->
         <dependency>

core-java-modules/core-java-lang-math-3/src/main/java/com/baeldung/math/rodcutting/RodCuttingProblem.java

@@ -0,0 +1,72 @@
+package com.baeldung.math.rodcutting;
+
+import java.util.Arrays;
+
+public class RodCuttingProblem {
+    static int maxRevenueG;
+    public static int usingRecursion(int[] prices, int n) {
+        if (n <= 0) {
+            return 0;
+        }
+        int maxRevenue = Integer.MIN_VALUE;
+
+        for (int i = 1; i <= n; i++) {
+            maxRevenue = Math.max(maxRevenue, prices[i - 1] + usingRecursion(prices, n - i));
+        }
+        return maxRevenue;
+    }
+
+    public static int usingMemoizedRecursion(int[] prices, int n) {
+        int[] memo = new int[n + 1];
+        Arrays.fill(memo, -1);
+
+        return memoizedHelper(prices, n, memo);
+    }
+
+    private static int memoizedHelper(int[] prices, int n, int[] memo) {
+        if (n <= 0) {
+            return 0;
+        }
+
+        if (memo[n] != -1) {
+            return memo[n];
+        }
+
+        int maxRevenue = Integer.MIN_VALUE;
+
+        for (int i = 1; i <= n; i++) {
+            maxRevenue = Math.max(maxRevenue, prices[i - 1] + memoizedHelper(prices, n - i, memo));
+        }
+
+        memo[n] = maxRevenue;
+        return maxRevenue;
+    }
+
+    public static int usingDynamicProgramming(int[] prices, int n) {
+        int[] dp = new int[n + 1];
+        for (int i = 1; i <= n; i++) {
+            int maxRevenue = Integer.MIN_VALUE;
+
+            for (int j = 1; j <= i; j++) {
+                maxRevenue = Math.max(maxRevenue, prices[j - 1] + dp[i - j]);
+            }
+            dp[i] = maxRevenue;
+        }
+        return dp[n];
+    }
+
+    public static int usingUnboundedKnapsack(int[] prices, int n) {
+        int[] dp = new int[n + 1];
+
+        for (int i = 1; i <= n; i++) {
+            for (int j = 0; j < prices.length; j++) {
+                if (j + 1 <= i) {
+                    dp[i] = Math.max(dp[i], dp[i - (j + 1)] + prices[j]);
+                }
+            }
+        }
+
+        return dp[n];
+    }
+
+}

core-java-modules/core-java-lang-math-3/src/test/java/com/baeldung/math/rodcutting/RodCuttingProblemUnitTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.math.rodcutting;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class RodCuttingProblemUnitTest {
+     @Test
+     void givenARod_whenUsingRecursion_thenFindMaxRevenue() {
+        int[] prices = {1, 5, 8, 9};
+        int rodLength = 4;
+        int maxRevenue = RodCuttingProblem.usingRecursion(prices, rodLength);
+        assertEquals(10, maxRevenue);
+    }
+
+    @Test
+    void givenARod_whenUsingMemoizedRecursion_thenFindMaxRevenue() {
+        int[] prices = {1, 5, 8, 9};
+        int rodLength = 4;
+        int maxRevenue = RodCuttingProblem.usingMemoizedRecursion(prices, rodLength);
+        assertEquals(10, maxRevenue);
+    }
+
+    @Test
+    void givenARod_whenUsingDynamicProgramming_thenFindMaxRevenue() {
+        int[] prices = {1, 5, 8, 9};
+        int rodLength = 4;
+        int maxRevenue = RodCuttingProblem.usingDynamicProgramming(prices, rodLength);
+        assertEquals(10, maxRevenue);
+    }
+
+    @Test
+    void givenARod_whenUsingGreedy_thenFindMaxRevenue() {
+        int[] prices = {1, 5, 8, 9};
+        int rodLength = 4;
+        int maxRevenue = RodCuttingProblem.usingUnboundedKnapsack(prices, rodLength);
+        assertEquals(10, maxRevenue);
+    }
+}

core-java-modules/core-java-lang-math/pom.xml

@@ -5,6 +5,14 @@
     <modelVersion>4.0.0</modelVersion>
     <artifactId>core-java-lang-math</artifactId>
     <name>core-java-lang-math</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>org.projectlombok</groupId>
@@ -13,13 +21,6 @@
             <scope>compile</scope>
         </dependency>
     </dependencies>
-    <packaging>jar</packaging>
-
-    <parent>
-        <groupId>com.baeldung.core-java-modules</groupId>
-        <artifactId>core-java-modules</artifactId>
-        <version>0.0.1-SNAPSHOT</version>
-    </parent>
 
     <build>
         <finalName>core-java-lang-math</finalName>

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

@@ -11,3 +11,4 @@ This module contains articles about Object-oriented programming (OOP) patterns i
 - [Should We Create an Interface for Only One Implementation?](https://www.baeldung.com/java-interface-single-implementation)
 - [How to Deep Copy an ArrayList in Java](https://www.baeldung.com/java-arraylist-deep-copy)
 - [Stateless Object in Java](https://www.baeldung.com/java-stateless-object)
+- [Mutable vs. Immutable Objects in Java](https://www.baeldung.com/java-mutable-vs-immutable-objects)

core-java-modules/core-java-lang-oop-patterns/pom.xml

@@ -32,7 +32,7 @@
     </dependencies>
 
     <properties>
-        <gson.version>2.8.2</gson.version>
+        <gson.version>2.10.1</gson.version>
     </properties>
 
 </project>

core-java-modules/core-java-lang-oop-patterns/src/main/java/com/baeldung/objectmutability/ImmutablePerson.java

@@ -0,0 +1,21 @@
+package com.baeldung.objectmutability;
+
+public final class ImmutablePerson {
+
+    private final String name;
+    private final int age;
+
+    public ImmutablePerson(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+}
+

core-java-modules/core-java-lang-oop-patterns/src/test/java/com/baeldung/objectmutability/ImmutableObjectExamplesUnitTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.objectmutability;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+
+public class ImmutableObjectExamplesUnitTest {
+
+    @Test
+    public void givenImmutableString_whenConcatString_thenNotSameAndCorrectValues() {
+        String originalString = "Hello";
+        String modifiedString = originalString.concat(" World");
+
+        assertNotSame(originalString, modifiedString);
+
+        assertEquals("Hello", originalString);
+        assertEquals("Hello World", modifiedString);
+    }
+
+    @Test
+    public void givenImmutableInteger_whenAddInteger_thenNotSameAndCorrectValue() {
+        Integer immutableInt = 42;
+        Integer modifiedInt = immutableInt + 8;
+
+        assertNotSame(immutableInt, modifiedInt);
+
+        assertEquals(42, (int) immutableInt);
+        assertEquals(50, (int) modifiedInt);
+    }
+}
+
+

core-java-modules/core-java-lang-oop-patterns/src/test/java/com/baeldung/objectmutability/ImmutablePersonUnitTest.java

@@ -0,0 +1,17 @@
+package com.baeldung.objectmutability;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ImmutablePersonUnitTest {
+
+    @Test
+    public void givenImmutablePerson_whenAccessFields_thenCorrectValues() {
+        ImmutablePerson person = new ImmutablePerson("John", 30);
+
+        assertEquals("John", person.getName());
+        assertEquals(30, person.getAge());
+    }
+}
+

core-java-modules/core-java-lang-oop-patterns/src/test/java/com/baeldung/objectmutability/MutableObjectExamplesUnitTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.objectmutability;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class MutableObjectExamplesUnitTest {
+
+    @Test
+    public void givenMutableString_whenAppendElement_thenCorrectValue() {
+        StringBuilder mutableString = new StringBuilder("Hello");
+        mutableString.append(" World");
+
+        assertEquals("Hello World", mutableString.toString());
+    }
+
+    @Test
+    public void givenMutableList_whenAddElement_thenCorrectSize() {
+        List<String> mutableList = new ArrayList<>();
+        mutableList.add("Java");
+
+        assertEquals(1, mutableList.size());
+    }
+}
+

core-java-modules/core-java-lang-operators-2/README.md

@@ -11,3 +11,4 @@ This module contains articles about Java operators
 - [Alternatives for instanceof Operator in Java](https://www.baeldung.com/java-instanceof-alternatives)
 - [What Does “––>” Mean in Java?](https://www.baeldung.com/java-minus-minus-greaterthan)
 - [All the Ways Java Uses the Colon Character](https://www.baeldung.com/java-colon)
+- [Convert Infix to Postfix Expressions in Java](https://www.baeldung.com/java-convert-infix-to-postfix-expressions)

core-java-modules/core-java-lang-operators-2/src/main/java/com/baeldung/infixpostfix/InfixToPostFixExpressionConversion.java

@@ -0,0 +1,67 @@
+package com.baeldung.infixpostfix;
+
+import java.util.Stack;
+
+public class InfixToPostFixExpressionConversion {
+
+    private int getPrecedenceScore(char ch) {
+        switch (ch) {
+        case '^':
+            return 3;
+
+        case '*':
+        case '/':
+            return 2;
+
+        case '+':
+        case '-':
+            return 1;
+        }
+        return -1;
+    }
+
+    private boolean isOperand(char ch) {
+        return (ch >= 'a' && ch <= 'z') || (ch >= '0' && ch <= '9');
+    }
+
+    private char associativity(char ch) {
+        if (ch == '^')
+            return 'R';
+        return 'L';
+    }
+
+    public String infixToPostfix(String infix) {
+        StringBuilder result = new StringBuilder();
+        Stack<Character> stack = new Stack<>();
+
+        for (int i = 0; i < infix.length(); i++) {
+            char ch = infix.charAt(i);
+
+            if (isOperand(ch)) {
+                result.append(ch);
+            } else if (ch == '(') {
+                stack.push(ch);
+            } else if (ch == ')') {
+                while (!stack.isEmpty() && stack.peek() != '(') {
+                    result.append(stack.pop());
+                }
+                stack.pop();
+            } else {
+                while (!stack.isEmpty() && (operatorPrecedenceCondition(infix, i, stack))) {
+                    result.append(stack.pop());
+                }
+                stack.push(ch);
+            }
+        }
+
+        while (!stack.isEmpty()) {
+            result.append(stack.pop());
+        }
+
+        return result.toString();
+    }
+
+    private boolean operatorPrecedenceCondition(String infix, int i, Stack<Character> stack) {
+        return getPrecedenceScore(infix.charAt(i)) < getPrecedenceScore(stack.peek()) || getPrecedenceScore(infix.charAt(i)) == getPrecedenceScore(stack.peek()) && associativity(infix.charAt(i)) == 'L';
+    }
+}

core-java-modules/core-java-lang-operators-2/src/test/java/com/baeldung/infixpostfix/InfixToPostfixExpressionUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.infixpostfix;
+
+import org.junit.Test;
+import org.junit.jupiter.api.Assertions;
+
+public class InfixToPostfixExpressionUnitTest {
+
+    @Test
+    public void givenSimpleOp_whenNoParenthesis_thenProduceValidPostfix() {
+        String infix = "a+b*c-d";
+        String postfix = "abc*+d-";
+
+        InfixToPostFixExpressionConversion obj = new InfixToPostFixExpressionConversion();
+
+        Assertions.assertEquals(postfix, obj.infixToPostfix(infix));
+    }
+
+    @Test
+    public void givenSimpleOp_whenWithParenthesis_thenProduceValidPostfix() {
+        String infix = "(a+b)*(c-d)";
+        String postfix = "ab+cd-*";
+
+        InfixToPostFixExpressionConversion obj = new InfixToPostFixExpressionConversion();
+
+        Assertions.assertEquals(postfix, obj.infixToPostfix(infix));
+    }
+
+    @Test
+    public void givenComplexOp_whenInputIsInfix_thenProduceValidPostfix() {
+        String infix = "a^b*(c^d-e)^(f+g*h)-i";
+        String postfix = "ab^cd^e-fgh*+^*i-";
+
+        InfixToPostFixExpressionConversion obj = new InfixToPostFixExpressionConversion();
+
+        Assertions.assertEquals(postfix, obj.infixToPostfix(infix));
+    }
+}