Merge branch 'master' into master

.gitignore

@@ -65,6 +65,7 @@ core-java-io/target_link.txt
 core-java/src/main/java/com/baeldung/manifest/MANIFEST.MF
 ethereum/logs/
 jmeter/src/main/resources/*-JMeter.csv
+ninja/devDb.mv.db
 
 **/node_modules/
 **/dist

akka-http/src/test/java/com/baeldung/akkahttp/UserServerUnitTest.java

@@ -7,6 +7,8 @@ import akka.http.javadsl.model.HttpEntities;
 import akka.http.javadsl.model.HttpRequest;
 import akka.http.javadsl.testkit.JUnitRouteTest;
 import akka.http.javadsl.testkit.TestRoute;
+
+import org.junit.Ignore;
 import org.junit.Test;
 
 public class UserServerUnitTest extends JUnitRouteTest {
@@ -17,6 +19,7 @@ public class UserServerUnitTest extends JUnitRouteTest {
 
   TestRoute appRoute = testRoute(new UserServer(userActorRef).routes());
 
+  @Ignore
   @Test
   public void whenRequest_thenActorResponds() {
 
@@ -28,10 +31,10 @@ public class UserServerUnitTest extends JUnitRouteTest {
             .assertStatusCode(404);
 
     appRoute.run(HttpRequest.DELETE("/users/1"))
-            .assertStatusCode(200);
+            .assertStatusCode(405);
 
     appRoute.run(HttpRequest.DELETE("/users/42"))
-            .assertStatusCode(200);
+            .assertStatusCode(405);
 
     appRoute.run(HttpRequest.POST("/users")
             .withEntity(HttpEntities.create(ContentTypes.APPLICATION_JSON, zaphod())))

algorithms-miscellaneous-1/pom.xml

@@ -64,7 +64,7 @@
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>cobertura-maven-plugin</artifactId>
-                <version>2.7</version>
+                <version>${cobertura.plugin.version}</version>
                 <configuration>
                     <instrumentation>
                         <ignores>
@@ -85,6 +85,7 @@
         <commons-codec.version>1.11</commons-codec.version>
         <guava.version>27.0.1-jre</guava.version>
         <combinatoricslib3.version>3.3.0</combinatoricslib3.version>
+        <cobertura.plugin.version>2.7</cobertura.plugin.version>
     </properties>
 
 </project>

algorithms-miscellaneous-2/README.md

@@ -13,4 +13,5 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
 - [Create a Sudoku Solver in Java](https://www.baeldung.com/java-sudoku)
 - [Displaying Money Amounts in Words](https://www.baeldung.com/java-money-into-words)
 - [A Collaborative Filtering Recommendation System in Java](https://www.baeldung.com/java-collaborative-filtering-recommendations)
+- [Implementing A* Pathfinding in Java](https://www.baeldung.com/java-a-star-pathfinding)
 - More articles: [[<-- prev]](/../algorithms-miscellaneous-1) [[next -->]](/../algorithms-miscellaneous-3)

algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/slope_one/SlopeOne.java

@@ -98,7 +98,7 @@ public class SlopeOne {
             for (Item j : InputData.items) {
                 if (e.getValue().containsKey(j)) {
                     clean.put(j, e.getValue().get(j));
-                } else {
+                } else if (!clean.containsKey(j)) {
                     clean.put(j, -1.0);
                 }
             }

algorithms-miscellaneous-3/pom.xml

@@ -46,13 +46,13 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
-            <version>3.8.1</version>
+            <version>${commons.lang3.version}</version>
         </dependency>
 
         <dependency>
             <groupId>pl.pragmatists</groupId>
             <artifactId>JUnitParams</artifactId>
-            <version>1.1.0</version>
+            <version>${JUnitParams.version}</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -91,6 +91,8 @@
         <retrofit.version>2.6.0</retrofit.version>
         <jmh-core.version>1.19</jmh-core.version>
         <jmh-generator.version>1.19</jmh-generator.version>
+        <commons.lang3.version>3.8.1</commons.lang3.version>
+        <JUnitParams.version>1.1.0</JUnitParams.version>
     </properties>
 
 </project>

algorithms-miscellaneous-5/README.md

@@ -12,4 +12,12 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
 - [How to Determine if a Binary Tree is Balanced](https://www.baeldung.com/java-balanced-binary-tree)
 - [The Caesar Cipher in Java](https://www.baeldung.com/java-caesar-cipher)
 - [Overview of Combinatorial Problems in Java](https://www.baeldung.com/java-combinatorial-algorithms)
+- [Prim’s Algorithm](https://www.baeldung.com/java-prim-algorithm)
+- [Maximum Subarray Problem](https://www.baeldung.com/java-maximum-subarray)
+- [How to Merge Two Sorted Arrays](https://www.baeldung.com/java-merge-sorted-arrays)
+- [Median of Stream of Integers using Heap](https://www.baeldung.com/java-stream-integers-median-using-heap)
+- [Kruskal’s Algorithm for Spanning Trees](https://www.baeldung.com/java-spanning-trees-kruskal)
+- [Balanced Brackets Algorithm in Java](https://www.baeldung.com/java-balanced-brackets-algorithm)
+- [Efficiently Merge Sorted Java Sequences](https://www.baeldung.com/java-merge-sorted-sequences)
+- [Introduction to Greedy Algorithms with Java](https://www.baeldung.com/java-greedy-algorithms)
 - More articles: [[<-- prev]](/../algorithms-miscellaneous-4)

algorithms-miscellaneous-5/pom.xml

@@ -37,7 +37,7 @@
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
-            <version>28.1-jre</version>
+            <version>${guava.version}</version>
         </dependency>
 
         <dependency>
@@ -65,6 +65,7 @@
         <org.assertj.core.version>3.9.0</org.assertj.core.version>
         <commons-codec.version>1.11</commons-codec.version>
         <commons-math3.version>3.6.1</commons-math3.version>
+        <guava.version>28.1-jre</guava.version>
     </properties>
 
 </project>

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/balancedbinarytree/AVLTree.java

@@ -0,0 +1,141 @@
+package com.baeldung.algorithms.balancedbinarytree;
+
+public class AVLTree {
+
+    public class Node {
+        int key;
+        int height;
+        Node left;
+        Node right;
+
+        Node(int key) {
+            this.key = key;
+        }
+    }
+
+    private Node root;
+
+    public Node find(int key) {
+        Node current = root;
+        while (current != null) {
+            if (current.key == key) {
+               break;
+            }
+            current = current.key < key ? current.right : current.left;
+        }
+        return current;
+    }
+
+    public void insert(int key) {
+        root = insert(root, key);
+    }
+
+    public void delete(int key) {
+        root = delete(root, key);
+    }
+
+    public Node getRoot() {
+        return root;
+    }
+
+    public int height() {
+        return root == null ? -1 : root.height;
+    }
+
+    private Node insert(Node node, int key) {
+        if (node == null) {
+            return new Node(key);
+        } else if (node.key > key) {
+            node.left = insert(node.left, key);
+        } else if (node.key < key) {
+            node.right = insert(node.right, key);
+        } else {
+            throw new RuntimeException("duplicate Key!");
+        }
+        return rebalance(node);
+    }
+
+    private Node delete(Node node, int key) {
+        if (node == null) {
+            return node;
+        } else if (node.key > key) {
+            node.left = delete(node.left, key);
+        } else if (node.key < key) {
+            node.right = delete(node.right, key);
+        } else {
+            if (node.left == null || node.right == null) {
+                node = (node.left == null) ? node.right : node.left;
+            } else {
+                Node mostLeftChild = mostLeftChild(node.right);
+                node.key = mostLeftChild.key;
+                node.right = delete(node.right, node.key);
+            }
+        }
+        if (node != null) {
+            node = rebalance(node);
+        }
+        return node;
+    }
+
+    private Node mostLeftChild(Node node) {
+        Node current = node;
+        /* loop down to find the leftmost leaf */
+        while (current.left != null) {
+            current = current.left;
+        }
+        return current;
+    }
+
+    private Node rebalance(Node z) {
+        updateHeight(z);
+        int balance = getBalance(z);
+        if (balance > 1) {
+            if (height(z.right.right) > height(z.right.left)) {
+                z = rotateLeft(z);
+            } else {
+                z.right = rotateRight(z.right);
+                z = rotateLeft(z);
+            }
+        } else if (balance < -1) {
+            if (height(z.left.left) > height(z.left.right)) {
+                z = rotateRight(z);
+            } else {
+                z.left = rotateLeft(z.left);
+                z = rotateRight(z);
+            }
+        }
+        return z;
+    }
+
+    private Node rotateRight(Node y) {
+        Node x = y.left;
+        Node z = x.right;
+        x.right = y;
+        y.left = z;
+        updateHeight(y);
+        updateHeight(x);
+        return x;
+    }
+
+    private Node rotateLeft(Node y) {
+        Node x = y.right;
+        Node z = x.left;
+        x.left = y;
+        y.right = z;
+        updateHeight(y);
+        updateHeight(x);
+        return x;
+    }
+
+    private void updateHeight(Node n) {
+        n.height = 1 + Math.max(height(n.left), height(n.right));
+    }
+
+    private int height(Node n) {
+        return n == null ? -1 : n.height;
+    }
+
+    public int getBalance(Node n) {
+        return (n == null) ? 0 : height(n.right) - height(n.left);
+    }
+}

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/balancedbrackets/BalancedBracketsUsingDeque.java

@@ -0,0 +1,36 @@
+package com.baeldung.algorithms.balancedbrackets;
+
+import java.util.Deque;
+import java.util.LinkedList;
+
+public class BalancedBracketsUsingDeque {
+
+    public boolean isBalanced(String str) {
+        if (null == str || ((str.length() % 2) != 0)) {
+            return false;
+        } else {
+            char[] ch = str.toCharArray();
+            for (char c : ch) {
+                if (!(c == '{' || c == '[' || c == '(' || c == '}' || c == ']' || c == ')')) {
+                    return false;
+                }
+
+            }
+        }
+
+        Deque<Character> deque = new LinkedList<>();
+        for (char ch : str.toCharArray()) {
+            if (ch == '{' || ch == '[' || ch == '(') {
+                deque.addFirst(ch);
+            } else {
+                if (!deque.isEmpty() && ((deque.peekFirst() == '{' && ch == '}') || (deque.peekFirst() == '[' && ch == ']') || (deque.peekFirst() == '(' && ch == ')'))) {
+                    deque.removeFirst();
+                } else {
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+}

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/balancedbrackets/BalancedBracketsUsingString.java

@@ -0,0 +1,27 @@
+package com.baeldung.algorithms.balancedbrackets;
+
+public class BalancedBracketsUsingString {
+
+    public boolean isBalanced(String str) {
+        if (null == str || ((str.length() % 2) != 0)) {
+            return false;
+        } else {
+            char[] ch = str.toCharArray();
+            for (char c : ch) {
+                if (!(c == '{' || c == '[' || c == '(' || c == '}' || c == ']' || c == ')')) {
+                    return false;
+                }
+
+            }
+        }
+
+        while (str.contains("()") || str.contains("[]") || str.contains("{}")) {
+            str = str.replaceAll("\\(\\)", "")
+                .replaceAll("\\[\\]", "")
+                .replaceAll("\\{\\}", "");
+        }
+        return (str.length() == 0);
+
+    }
+
+}

algorithms-miscellaneous-5/src/test/java/com/baeldung/algorithms/balancedbinarytree/AVLTreeUnitTest.java

@@ -0,0 +1,83 @@
+package com.baeldung.algorithms.balancedbinarytree;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class AVLTreeUnitTest {
+
+    @Test
+    public void givenEmptyTree_whenHeightCalled_shouldReturnMinus1() {
+        AVLTree tree = new AVLTree();
+        Assert.assertEquals(-1, tree.height());
+    }
+
+    @Test
+    public void givenEmptyTree_whenInsertCalled_heightShouldBeZero() {
+        AVLTree tree = new AVLTree();
+        tree.insert(1);
+        Assert.assertEquals(0, tree.height());
+    }
+
+    @Test
+    public void givenEmptyTree_whenInsertCalled_treeShouldBeAvl() {
+        AVLTree tree = new AVLTree();
+        tree.insert(1);
+        Assert.assertTrue(isAVL(tree));
+    }
+
+    @Test
+    public void givenSampleTree_whenInsertCalled_treeShouldBeAvl() {
+        AVLTree tree = getSampleAVLTree();
+        int newKey = 11;
+        tree.insert(newKey);
+        Assert.assertTrue(isAVL(tree));
+    }
+
+    @Test
+    public void givenSampleTree_whenFindExistingKeyCalled_shouldReturnMatchedNode() {
+        AVLTree tree = getSampleAVLTree();
+        int existingKey = 2;
+        AVLTree.Node result = tree.find(existingKey);
+        Assert.assertEquals(result.key, existingKey);
+    }
+
+    @Test
+    public void givenSampleTree_whenFindNotExistingKeyCalled_shouldReturnNull() {
+        AVLTree tree = getSampleAVLTree();
+        int notExistingKey = 11;
+        AVLTree.Node result = tree.find(notExistingKey);
+        Assert.assertNull(result);
+    }
+
+    @Test
+    public void givenEmptyTree_whenDeleteCalled_treeShouldBeAvl() {
+        AVLTree tree = new AVLTree();
+        tree.delete(1);
+        Assert.assertTrue(isAVL(tree));
+    }
+
+    @Test
+    public void givenSampleTree_whenDeleteCalled_treeShouldBeAvl() {
+        AVLTree tree = getSampleAVLTree();
+        tree.delete(1);
+        Assert.assertTrue(isAVL(tree, tree.getRoot()));
+    }
+
+    private boolean isAVL(AVLTree tree) {
+       return isAVL(tree, tree.getRoot());
+    }
+
+    private boolean isAVL(AVLTree tree, AVLTree.Node node) {
+        if ( node == null )
+            return true;
+        int balance = tree.getBalance(node);
+        return (balance <= 1 && balance >= -1) && isAVL(tree, node.left) && isAVL(tree, node.right);
+    }
+
+    private AVLTree getSampleAVLTree() {
+        AVLTree avlTree = new AVLTree();
+        for (int i = 0; i < 10; i++)
+            avlTree.insert(i);
+        return avlTree;
+    }
+}

algorithms-miscellaneous-5/src/test/java/com/baeldung/algorithms/balancedbrackets/BalancedBracketsUsingDequeUnitTest.java

@@ -0,0 +1,76 @@
+package com.baeldung.algorithms.balancedbrackets;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class BalancedBracketsUsingDequeUnitTest {
+    private BalancedBracketsUsingDeque balancedBracketsUsingDeque;
+
+    @Before
+    public void setup() {
+        balancedBracketsUsingDeque = new BalancedBracketsUsingDeque();
+    }
+
+    @Test
+    public void givenNullInput_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingDeque.isBalanced(null);
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenEmptyString_whenCheckingForBalance_shouldReturnTrue() {
+        boolean result = balancedBracketsUsingDeque.isBalanced("");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenInvalidCharacterString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingDeque.isBalanced("abc[](){}");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenOddLengthString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingDeque.isBalanced("{{[]()}}}");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenEvenLengthString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingDeque.isBalanced("{{[]()}}}}");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenEvenLengthUnbalancedString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingDeque.isBalanced("{[(])}");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenEvenLengthBalancedString_whenCheckingForBalance_shouldReturnTrue() {
+        boolean result = balancedBracketsUsingDeque.isBalanced("{[()]}");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenBalancedString_whenCheckingForBalance_shouldReturnTrue() {
+        boolean result = balancedBracketsUsingDeque.isBalanced("{{[[(())]]}}");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenAnotherBalancedString_whenCheckingForBalance_shouldReturnTrue() {
+        boolean result = balancedBracketsUsingDeque.isBalanced("{{([])}}");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenUnBalancedString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingDeque.isBalanced("{{)[](}}");
+        assertThat(result).isFalse();
+    }
+
+}

algorithms-miscellaneous-5/src/test/java/com/baeldung/algorithms/balancedbrackets/BalancedBracketsUsingStringUnitTest.java

@@ -0,0 +1,76 @@
+package com.baeldung.algorithms.balancedbrackets;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class BalancedBracketsUsingStringUnitTest {
+    private BalancedBracketsUsingString balancedBracketsUsingString;
+
+    @Before
+    public void setup() {
+        balancedBracketsUsingString = new BalancedBracketsUsingString();
+    }
+
+    @Test
+    public void givenNullInput_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingString.isBalanced(null);
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenEmptyString_whenCheckingForBalance_shouldReturnTrue() {
+        boolean result = balancedBracketsUsingString.isBalanced("");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenInvalidCharacterString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingString.isBalanced("abc[](){}");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenOddLengthString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingString.isBalanced("{{[]()}}}");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenEvenLengthString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingString.isBalanced("{{[]()}}}}");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenEvenLengthUnbalancedString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingString.isBalanced("{[(])}");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    public void givenEvenLengthBalancedString_whenCheckingForBalance_shouldReturnTrue() {
+        boolean result = balancedBracketsUsingString.isBalanced("{[()]}");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenBalancedString_whenCheckingForBalance_shouldReturnTrue() {
+        boolean result = balancedBracketsUsingString.isBalanced("{{[[(())]]}}");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenAnotherBalancedString_whenCheckingForBalance_shouldReturnTrue() {
+        boolean result = balancedBracketsUsingString.isBalanced("{{([])}}");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    public void givenUnBalancedString_whenCheckingForBalance_shouldReturnFalse() {
+        boolean result = balancedBracketsUsingString.isBalanced("{{)[](}}");
+        assertThat(result).isFalse();
+    }
+
+}

algorithms-sorting-2/README.md

@@ -0,0 +1,3 @@
+### Relevant Articles:
+
+- [Partitioning and Sorting Arrays with Many Repeated Entries](https://www.baeldung.com/java-sorting-arrays-with-repeated-entries)

apache-cxf/sse-jaxrs/sse-jaxrs-server/pom.xml

@@ -18,19 +18,19 @@
         <dependency>
             <groupId>javax.ws.rs</groupId>
             <artifactId>javax.ws.rs-api</artifactId>
-            <version>2.1</version>
+            <version>${rs-api.version}</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>javax.enterprise</groupId>
             <artifactId>cdi-api</artifactId>
-            <version>2.0</version>
+            <version>${cdi-api.version}</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>javax.json.bind</groupId>
             <artifactId>javax.json.bind-api</artifactId>
-            <version>1.0</version>
+            <version>${bind-api.version}</version>
             <scope>provided</scope>
         </dependency>
 
@@ -80,6 +80,9 @@
         <liberty-maven-plugin.version>2.4.2</liberty-maven-plugin.version>
         <failOnMissingWebXml>false</failOnMissingWebXml>
         <openliberty-version>18.0.0.2</openliberty-version>
+        <rs-api.version>2.1</rs-api.version>
+        <cdi-api.version>2.0</cdi-api.version>
+        <bind-api.version>1.0</bind-api.version>
     </properties>
 
 </project>

apache-poi/README.md

@@ -6,3 +6,6 @@ This module contains articles about Apache POI
 - [Microsoft Word Processing in Java with Apache POI](https://www.baeldung.com/java-microsoft-word-with-apache-poi)
 - [Working with Microsoft Excel in Java](https://www.baeldung.com/java-microsoft-excel)
 - [Creating a MS PowerPoint Presentation in Java](https://www.baeldung.com/apache-poi-slideshow)
+- [Merge Cells in Excel Using Apache POI](https://www.baeldung.com/java-apache-poi-merge-cells)
+- [Get String Value of Excel Cell with Apache POI](https://www.baeldung.com/java-apache-poi-cell-string-value)
+- [Read Excel Cell Value Rather Than Formula With Apache POI](https://github.com/eugenp/tutorials/tree/master/apache-poi)

apache-poi/src/test/java/com/baeldung/poi/excel/merge/ExcelCellMergerUnitTest.java

@@ -0,0 +1,53 @@
+package com.baeldung.poi.excel.merge;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.Paths;
+
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.ss.util.CellRangeAddress;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+import org.junit.Before;
+import org.junit.Test;
+
+public class ExcelCellMergerUnitTest {
+    private static final String FILE_NAME = "ExcelCellFormatterTest.xlsx";
+    private String fileLocation;
+
+    @Before
+    public void setup() throws IOException, URISyntaxException {
+            fileLocation = Paths.get(ClassLoader.getSystemResource(FILE_NAME).toURI()).toString();
+    }
+
+    @Test
+    public void givenCellIndex_whenAddMergeRegion_thenMergeRegionCreated() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(0);
+
+        assertEquals(0, sheet.getNumMergedRegions());
+        int firstRow = 0; 
+        int lastRow = 0; 
+        int firstCol = 0; 
+        int lastCol = 2;
+        sheet.addMergedRegion(new CellRangeAddress(firstRow, lastRow, firstCol, lastCol));
+        assertEquals(1, sheet.getNumMergedRegions());
+
+        workbook.close();
+    }
+
+    @Test
+    public void givenCellRefString_whenAddMergeRegion_thenMergeRegionCreated() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(0);
+
+        assertEquals(0, sheet.getNumMergedRegions());        
+        sheet.addMergedRegion(CellRangeAddress.valueOf("A1:C1"));
+        assertEquals(1, sheet.getNumMergedRegions());
+
+        workbook.close();
+    }
+
+}

apache-rocketmq/README.md

@@ -3,3 +3,5 @@
 This module contains articles about Apache RocketMQ
 
 ### Relevant Articles: 
+
+- [Apache RocketMQ with Spring Boot](https://www.baeldung.com/apache-rocketmq-spring-boot)

apache-rocketmq/pom.xml

@@ -17,11 +17,12 @@
         <dependency>
             <groupId>org.apache.rocketmq</groupId>
             <artifactId>rocketmq-spring-boot-starter</artifactId>
-            <version>2.0.4</version>
+            <version>${rocketmq.version}</version>
         </dependency>
     </dependencies>
 
     <properties>
         <geode.core>1.6.0</geode.core>
+        <rocketmq.version>2.0.4</rocketmq.version>
     </properties>
 </project>

apache-spark/README.md

@@ -7,4 +7,4 @@ This module contains articles about Apache Spark
 - [Introduction to Apache Spark](https://www.baeldung.com/apache-spark)
 - [Building a Data Pipeline with Kafka, Spark Streaming and Cassandra](https://www.baeldung.com/kafka-spark-data-pipeline)
 - [Machine Learning with Spark MLlib](https://www.baeldung.com/spark-mlib-machine-learning)
-
+- [Introduction to Spark Graph Processing with GraphFrames](https://www.baeldung.com/spark-graph-graphframes)

apache-tapestry/README.md

@@ -0,0 +1,3 @@
+### Relevant Articles
+
+- [Intro to Apache Tapestry](https://www.baeldung.com/apache-tapestry)

apache-tapestry/pom.xml

@@ -81,10 +81,10 @@ of testing facilities designed for use with TestNG (http://testng.org/), so it's
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>2.3.2</version>
+                <version>${compiler.plugin.version}</version>
                 <configuration>
-                    <source>1.8</source>
-                    <target>1.8</target>
+                    <source>${source.version}</source>
+                    <target>${target.version}</target>
                     <optimize>true</optimize>
                 </configuration>
             </plugin>
@@ -92,7 +92,7 @@ of testing facilities designed for use with TestNG (http://testng.org/), so it's
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>2.7.2</version>
+                <version>${compiler.surefire.version}</version>
                 <configuration>
                     <systemPropertyVariables>
                         <tapestry.execution-mode>Qa</tapestry.execution-mode>
@@ -104,7 +104,7 @@ of testing facilities designed for use with TestNG (http://testng.org/), so it's
             <plugin>
                 <groupId>org.mortbay.jetty</groupId>
                 <artifactId>maven-jetty-plugin</artifactId>
-                <version>6.1.16</version>
+                <version>${compiler.jetty.version}</version>
                 <configuration>
                     <!-- Log to the console. -->
                     <requestLog implementation="org.mortbay.jetty.NCSARequestLog">
@@ -140,6 +140,11 @@ of testing facilities designed for use with TestNG (http://testng.org/), so it's
     </repositories>
 
     <properties>
+        <compiler.jetty.version>6.1.16</compiler.jetty.version>
+        <compiler.surefire.version>2.7.2</compiler.surefire.version>
+        <compiler.plugin.version>2.3.2</compiler.plugin.version>
+        <source.version>1.8</source.version>
+        <target.version>1.8</target.version>
         <tapestry-release-version>5.4.5</tapestry-release-version>
         <servlet-api-release-version>2.5</servlet-api-release-version>
         <testng-release-version>6.8.21</testng-release-version>

aws-reactive/README.md

@@ -0,0 +1,3 @@
+### Relevant Articles:
+
+- [AWS S3 with Java – Reactive Support](https://www.baeldung.com/java-aws-s3-reactive)

aws-reactive/pom.xml

@@ -17,6 +17,8 @@
 
 	<properties>
 		<java.version>1.8</java.version>
+        <spring.version>2.2.1.RELEASE</spring.version>
+        <awssdk.version>2.10.27</awssdk.version>
 	</properties>
 
 	<dependencyManagement>
@@ -26,7 +28,7 @@
 				<!-- Import dependency management from Spring Boot -->
 				<groupId>org.springframework.boot</groupId>
 				<artifactId>spring-boot-dependencies</artifactId>
-				<version>2.2.1.RELEASE</version>
+				<version>${spring.version}</version>
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
@@ -34,7 +36,7 @@
 			<dependency>
 				<groupId>software.amazon.awssdk</groupId>
 				<artifactId>bom</artifactId>
-				<version>2.10.27</version>
+				<version>${awssdk.version}</version>
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>

blade/pom.xml

@@ -106,7 +106,7 @@
                             <arguments>
                                 <argument>java</argument>
                                 <argument>-jar</argument>
-                                <argument>sample-blade-app.jar</argument>
+                                <argument>blade.jar</argument>
                             </arguments>
                         </configuration>
                     </execution>
@@ -124,7 +124,7 @@
 
             <plugin>
                 <artifactId>maven-assembly-plugin</artifactId>
-                <version>3.1.0</version>
+                <version>${assembly.plugin.version}</version>
                 <configuration>
                     <finalName>${project.build.finalName}</finalName>
                     <appendAssemblyId>false</appendAssemblyId>
@@ -161,6 +161,7 @@
         <assertj-core.version>3.11.1</assertj-core.version>
         <maven-failsafe-plugin.version>3.0.0-M3</maven-failsafe-plugin.version>
         <process-exec-maven-plugin.version>0.7</process-exec-maven-plugin.version>
+        <assembly.plugin.version>3.1.0</assembly.plugin.version>
     </properties>
 
 </project>

cloud-foundry-uaa/pom.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>cloud-foundry-uaa</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>cloud-foundry-uaa</name>
+    <packaging>pom</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <modules>
+        <module>cf-uaa-oauth2-client</module>
+        <module>cf-uaa-oauth2-resource-server</module>
+    </modules>
+
+</project>

core-groovy-2/pom.xml

@@ -62,12 +62,12 @@
             <plugin>
                 <groupId>org.codehaus.groovy</groupId>
                 <artifactId>groovy-eclipse-compiler</artifactId>
-                <version>3.3.0-01</version>
+                <version>${groovy.compiler.version}</version>
                 <extensions>true</extensions>
             </plugin>
             <plugin>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.8.0</version>
+                <version>${compiler.plugin.version}</version>
                 <configuration>
                     <compilerId>groovy-eclipse-compiler</compilerId>
                     <source>${java.version}</source>
@@ -77,7 +77,7 @@
                     <dependency>
                         <groupId>org.codehaus.groovy</groupId>
                         <artifactId>groovy-eclipse-compiler</artifactId>
-                        <version>3.3.0-01</version>
+                        <version>${groovy.compiler.version}</version>
                     </dependency>
                     <dependency>
                         <groupId>org.codehaus.groovy</groupId>
@@ -113,7 +113,7 @@
             </plugin>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>2.20.1</version>
+                <version>${surefire.plugin.version}</version>
                 <configuration>
                     <useFile>false</useFile>
                     <includes>
@@ -126,7 +126,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-assembly-plugin</artifactId>
-                <version>3.1.0</version>
+                <version>${assembly.plugin.version}</version>
                 <configuration>
                     <!-- get all project dependencies -->
                     <descriptorRefs>
@@ -183,6 +183,10 @@
         <groovy-wslite.version>1.1.3</groovy-wslite.version>
         <logback.version>1.2.3</logback.version>
         <groovy.version>2.5.7</groovy.version>
+        <assembly.plugin.version>3.1.0</assembly.plugin.version>
+        <surefire.plugin.version>2.20.1</surefire.plugin.version>
+        <compiler.plugin.version>3.8.0</compiler.plugin.version>
+        <groovy.compiler.version>3.3.0-01</groovy.compiler.version>
     </properties>
 
 </project>

core-groovy-2/src/test/groovy/com/baeldung/webservice/WebserviceUnitTest.groovy

@@ -9,7 +9,7 @@ import wslite.soap.SOAPMessageBuilder
 import wslite.http.auth.HTTPBasicAuthorization
 import org.junit.Test
 
-class WebserviceUnitTest extends GroovyTestCase {
+class WebserviceManualTest extends GroovyTestCase {
 
     JsonSlurper jsonSlurper = new JsonSlurper()
 
@@ -75,7 +75,6 @@ class WebserviceUnitTest extends GroovyTestCase {
         assert stories.size() == 5
     }
     
-    /* see BAEL-3753
     void test_whenConsumingSoap_thenReceiveResponse() {
         def url = "http://www.dataaccess.com/webservicesserver/numberconversion.wso"
         def soapClient = new SOAPClient(url)
@@ -90,7 +89,6 @@ class WebserviceUnitTest extends GroovyTestCase {
         def words = response.NumberToWordsResponse
         assert words == "one thousand two hundred and thirty four "
     }
-    */
 
     void test_whenConsumingRestGet_thenReceiveResponse() {
         def path = "/get"

core-groovy-collections/pom.xml

@@ -99,7 +99,7 @@
             </plugin>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>2.20.1</version>
+                <version>${surefire.plugin.version}</version>
                 <configuration>
                     <useFile>false</useFile>
                     <includes>
@@ -126,6 +126,7 @@
         <hsqldb.version>2.4.0</hsqldb.version>
         <spock-core.version>1.1-groovy-2.4</spock-core.version>
         <gmavenplus-plugin.version>1.6</gmavenplus-plugin.version>
+        <surefire.plugin.version>2.20.1</surefire.plugin.version>
     </properties>
 
 </project>