Merge branch 'master' of https://github.com/eugenp/tutorials into task/BAEL-20665

# Conflicts:
#	core-groovy-2/src/test/groovy/com/baeldung/metaprogramming/MetaprogrammingUnitTest.groovy
#	core-java-modules/pom.xml
#	pom.xml

algorithms-miscellaneous-3/README.md

@@ -15,5 +15,4 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
 - [Creating a Triangle with for Loops in Java](https://www.baeldung.com/java-print-triangle)
 - [Efficient Word Frequency Calculator in Java](https://www.baeldung.com/java-word-frequency)
 - [The K-Means Clustering Algorithm in Java](https://www.baeldung.com/java-k-means-clustering-algorithm)
-- [Creating a Custom Annotation in Java](https://www.baeldung.com/java-custom-annotation)
 - More articles: [[<-- prev]](/algorithms-miscellaneous-2) [[next -->]](/algorithms-miscellaneous-4)

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/greedy/GreedyAlgorithm.java

@@ -15,7 +15,7 @@ public class GreedyAlgorithm {
         this.fp = new FollowersPath();
     }
     
-    public long findMostFollowersPath(String account) throws Exception {        
+    public long findMostFollowersPath(String account) {
         long max = 0;
         SocialUser toFollow = null;
         
@@ -31,12 +31,8 @@ public class GreedyAlgorithm {
         if (currentLevel < maxLevel - 1) {
             currentLevel++;
             max += findMostFollowersPath(toFollow.getUsername());
-            //fp.addFollower(toFollow.getUsername(), max);
-            //fp.addCount(max);
             return max;
         } else {
-            //fp.addFollower(toFollow.getUsername(), max);
-            //fp.addCount(max);
             return max;
         }            
     }

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/greedy/NonGreedyAlgorithm.java

@@ -13,9 +13,8 @@ public class NonGreedyAlgorithm {
         this.tc = tc;
         this.currentLevel = level;
     }
-    
-    
-    public long findMostFollowersPath(String account) throws Exception {        
+      
+    public long findMostFollowersPath(String account) {
         List<SocialUser> followers = tc.getFollowers(account);
         long total = currentLevel > 0 ? followers.size() : 0;
 

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/greedy/SocialConnector.java

@@ -20,9 +20,9 @@ public class SocialConnector {
         return this.isCounterEnabled;
     }
     
-    public List<SocialUser> getFollowers(String account) throws Exception {
+    public List<SocialUser> getFollowers(String account) {
         if (counter < 0)
-            throw new Exception ("API limit reached");
+            throw new IllegalStateException ("API limit reached");
         else {
             if(this.isCounterEnabled) counter--;
             for(SocialUser user : users) {

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/minheapmerge/HeapNode.java

@@ -0,0 +1,13 @@
+package com.baeldung.algorithms.minheapmerge;
+
+public class HeapNode {
+
+    int element;
+    int arrayIndex;
+    int nextElementIndex = 1;
+
+    public HeapNode(int element, int arrayIndex) {
+        this.element = element;
+        this.arrayIndex = arrayIndex;
+    }
+}

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/minheapmerge/MinHeap.java

@@ -0,0 +1,88 @@
+package com.baeldung.algorithms.minheapmerge;
+
+public class MinHeap {
+
+    HeapNode[] heapNodes;
+
+    public MinHeap(HeapNode heapNodes[]) {
+        this.heapNodes = heapNodes;
+        heapifyFromLastLeafsParent();
+    }
+
+    void heapifyFromLastLeafsParent() {
+        int lastLeafsParentIndex = getParentNodeIndex(heapNodes.length);
+        while (lastLeafsParentIndex >= 0) {
+            heapify(lastLeafsParentIndex);
+            lastLeafsParentIndex--;
+        }
+    }
+
+    void heapify(int index) {
+        int leftNodeIndex = getLeftNodeIndex(index);
+        int rightNodeIndex = getRightNodeIndex(index);
+        int smallestElementIndex = index;
+        if (leftNodeIndex < heapNodes.length && heapNodes[leftNodeIndex].element < heapNodes[index].element) {
+            smallestElementIndex = leftNodeIndex;
+        }
+        if (rightNodeIndex < heapNodes.length && heapNodes[rightNodeIndex].element < heapNodes[smallestElementIndex].element) {
+            smallestElementIndex = rightNodeIndex;
+        }
+        if (smallestElementIndex != index) {
+            swap(index, smallestElementIndex);
+            heapify(smallestElementIndex);
+        }
+    }
+
+    int getParentNodeIndex(int index) {
+        return (index - 1) / 2;
+    }
+
+    int getLeftNodeIndex(int index) {
+        return (2 * index + 1);
+    }
+
+    int getRightNodeIndex(int index) {
+        return (2 * index + 2);
+    }
+
+    HeapNode getRootNode() {
+        return heapNodes[0];
+    }
+
+    void heapifyFromRoot() {
+        heapify(0);
+    }
+
+    void swap(int i, int j) {
+        HeapNode temp = heapNodes[i];
+        heapNodes[i] = heapNodes[j];
+        heapNodes[j] = temp;
+    }
+    
+    static int[] merge(int[][] array) {
+        HeapNode[] heapNodes = new HeapNode[array.length];
+        int resultingArraySize = 0;
+
+        for (int i = 0; i < array.length; i++) {
+            HeapNode node = new HeapNode(array[i][0], i);
+            heapNodes[i] = node;
+            resultingArraySize += array[i].length;
+        }
+        
+        MinHeap minHeap = new MinHeap(heapNodes);
+        int[] resultingArray = new int[resultingArraySize];
+
+        for (int i = 0; i < resultingArraySize; i++) {
+            HeapNode root = minHeap.getRootNode();
+            resultingArray[i] = root.element;
+
+            if (root.nextElementIndex < array[root.arrayIndex].length) {
+                root.element = array[root.arrayIndex][root.nextElementIndex++];
+            } else {
+                root.element = Integer.MAX_VALUE;
+            }
+            minHeap.heapifyFromRoot();
+        }
+        return resultingArray;
+    }
+}

algorithms-miscellaneous-5/src/test/java/com/baeldung/algorithms/greedy/GreedyAlgorithmUnitTest.java

@@ -35,21 +35,21 @@ public class GreedyAlgorithmUnitTest {
     }
 
     @Test
-    public void greedyAlgorithmTest() throws Exception {
+    public void greedyAlgorithmTest() {
         GreedyAlgorithm ga = new GreedyAlgorithm(prepareNetwork());
         assertEquals(ga.findMostFollowersPath("root"), 5);
     }
 
     @Test
-    public void nongreedyAlgorithmTest() throws Exception {
+    public void nongreedyAlgorithmTest() {
         NonGreedyAlgorithm nga = new NonGreedyAlgorithm(prepareNetwork(), 0);
-        Assertions.assertThrows(Exception.class, () -> {
+        Assertions.assertThrows(IllegalStateException.class, () -> {
             nga.findMostFollowersPath("root");
           });
     }
 
     @Test
-    public void nongreedyAlgorithmUnboundedTest() throws Exception {
+    public void nongreedyAlgorithmUnboundedTest() {
         SocialConnector sc = prepareNetwork();
         sc.switchCounter();
         NonGreedyAlgorithm nga = new NonGreedyAlgorithm(sc, 0);

algorithms-miscellaneous-5/src/test/java/com/baeldung/algorithms/minheapmerge/MinHeapUnitTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.algorithms.minheapmerge;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import org.junit.Test;
+
+public class MinHeapUnitTest {
+
+    private final int[][] inputArray = { { 0, 6 }, { 1, 5, 10, 100 }, { 2, 4, 200, 650 } };
+    private final int[] expectedArray = { 0, 1, 2, 4, 5, 6, 10, 100, 200, 650 };
+
+    @Test
+    public void givenSortedArrays_whenMerged_thenShouldReturnASingleSortedarray() {
+        int[] resultArray = MinHeap.merge(inputArray);
+        
+        assertThat(resultArray.length, is(equalTo(10)));
+        assertThat(resultArray, is(equalTo(expectedArray)));
+    }
+    
+}

algorithms-searching/README.md

@@ -9,3 +9,4 @@ This module contains articles about searching algorithms.
 - [Breadth-First Search Algorithm in Java](https://www.baeldung.com/java-breadth-first-search)
 - [String Search Algorithms for Large Texts](https://www.baeldung.com/java-full-text-search-algorithms)
 - [Monte Carlo Tree Search for Tic-Tac-Toe Game](https://www.baeldung.com/java-monte-carlo-tree-search)
+- [Range Search Algorithm in Java](https://www.baeldung.com/java-range-search)

algorithms-sorting-2/.gitignore

@@ -0,0 +1,4 @@
+/target/
+.settings/
+.classpath
+.project

algorithms-sorting-2/pom.xml

@@ -0,0 +1,64 @@
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 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>algorithms-sorting-2</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-sorting-2</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </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>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>${junit-jupiter-api.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${org.assertj.core.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>exec-maven-plugin</artifactId>
+                    <version>${exec-maven-plugin.version}</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+    <properties>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <org.assertj.core.version>3.9.0</org.assertj.core.version>
+        <commons-codec.version>1.11</commons-codec.version>
+        <junit-jupiter-api.version>5.3.1</junit-jupiter-api.version>
+    </properties>
+
+</project>

algorithms-sorting-2/src/main/java/com/baeldung/algorithms/quicksort/BentleyMcIlroyPartioning.java

@@ -0,0 +1,66 @@
+package com.baeldung.algorithms.quicksort;
+
+import static com.baeldung.algorithms.quicksort.SortingUtils.swap;
+
+public class BentleyMcIlroyPartioning {
+
+    public static Partition partition(int input[], int begin, int end) {
+        int left = begin, right = end;
+        int leftEqualKeysCount = 0, rightEqualKeysCount = 0;
+
+        int partitioningValue = input[end];
+
+        while (true) {
+            while (input[left] < partitioningValue)
+                left++;
+
+            while (input[right] > partitioningValue) {
+                if (right == begin)
+                    break;
+                right--;
+            }
+
+            if (left == right && input[left] == partitioningValue) {
+                swap(input, begin + leftEqualKeysCount, left);
+                leftEqualKeysCount++;
+                left++;
+            }
+
+            if (left >= right) {
+                break;
+            }
+
+            swap(input, left, right);
+
+            if (input[left] == partitioningValue) {
+                swap(input, begin + leftEqualKeysCount, left);
+                leftEqualKeysCount++;
+            }
+
+            if (input[right] == partitioningValue) {
+                swap(input, right, end - rightEqualKeysCount);
+                rightEqualKeysCount++;
+            }
+            left++; right--;
+        }
+        right = left - 1;
+        for (int k = begin; k < begin + leftEqualKeysCount; k++, right--) {
+            if (right >= begin + leftEqualKeysCount)
+                swap(input, k, right);
+        }
+        for (int k = end; k > end - rightEqualKeysCount; k--, left++) {
+            if (left <= end - rightEqualKeysCount)
+                swap(input, left, k);
+        }
+        return new Partition(right + 1, left - 1);
+    }
+
+    public static void quicksort(int input[], int begin, int end) {
+        if (end <= begin)
+            return;
+        Partition middlePartition = partition(input, begin, end);
+        quicksort(input, begin, middlePartition.getLeft() - 1);
+        quicksort(input, middlePartition.getRight() + 1, end);
+    }
+
+}

algorithms-sorting-2/src/main/java/com/baeldung/algorithms/quicksort/DutchNationalFlagPartioning.java

@@ -0,0 +1,38 @@
+package com.baeldung.algorithms.quicksort;
+
+import static com.baeldung.algorithms.quicksort.SortingUtils.compare;
+import static com.baeldung.algorithms.quicksort.SortingUtils.swap;
+
+public class DutchNationalFlagPartioning {
+
+    public static Partition partition(int[] a, int begin, int end) {
+        int lt = begin, current = begin, gt = end;
+        int partitioningValue = a[begin];
+
+        while (current <= gt) {
+            int compareCurrent = compare(a[current], partitioningValue);
+            switch (compareCurrent) {
+                case -1:
+                    swap(a, current++, lt++);
+                    break;
+                case 0:
+                    current++;
+                    break;
+                case 1:
+                    swap(a, current, gt--);
+                    break;
+            }
+        }
+        return new Partition(lt, gt);
+    }
+
+    public static void quicksort(int[] input, int begin, int end) {
+        if (end <= begin)
+            return;
+
+        Partition middlePartition = partition(input, begin, end);
+
+        quicksort(input, begin, middlePartition.getLeft() - 1);
+        quicksort(input, middlePartition.getRight() + 1, end);
+    }
+}

algorithms-sorting-2/src/main/java/com/baeldung/algorithms/quicksort/Partition.java

@@ -0,0 +1,29 @@
+package com.baeldung.algorithms.quicksort;
+
+public class Partition {
+    private int left;
+    private int right;
+
+    public Partition(int left, int right) {
+        super();
+        this.left = left;
+        this.right = right;
+    }
+
+    public int getLeft() {
+        return left;
+    }
+
+    public void setLeft(int left) {
+        this.left = left;
+    }
+
+    public int getRight() {
+        return right;
+    }
+
+    public void setRight(int right) {
+        this.right = right;
+    }
+
+}

algorithms-sorting-2/src/main/java/com/baeldung/algorithms/quicksort/SortingUtils.java

@@ -0,0 +1,32 @@
+package com.baeldung.algorithms.quicksort;
+
+public class SortingUtils {
+
+    public static void swap(int[] array, int position1, int position2) {
+        if (position1 != position2) {
+            int temp = array[position1];
+            array[position1] = array[position2];
+            array[position2] = temp;
+        }
+    }
+
+    public static int compare(int num1, int num2) {
+        if (num1 > num2)
+            return 1;
+        else if (num1 < num2)
+            return -1;
+        else
+            return 0;
+    }
+
+    public static void printArray(int[] array) {
+        if (array == null) {
+            return;
+        }
+        for (int e : array) {
+            System.out.print(e + " ");
+        }
+        System.out.println();
+    }
+
+}

algorithms-sorting-2/src/main/resources/logback.xml

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

algorithms-sorting-2/src/test/java/com/baeldung/algorithms/quicksort/BentleyMcilroyPartitioningUnitTest.java

@@ -0,0 +1,16 @@
+package com.baeldung.algorithms.quicksort;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class BentleyMcilroyPartitioningUnitTest {
+
+    @Test
+    public void given_IntegerArray_whenSortedWithBentleyMcilroyPartitioning_thenGetSortedArray() {
+        int[] actual = {3, 2, 2, 2, 3, 7, 7, 3, 2, 2, 7, 3, 3};
+        int[] expected = {2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 7, 7, 7};
+        BentleyMcIlroyPartioning.quicksort(actual, 0, actual.length - 1);
+        Assert.assertArrayEquals(expected, actual);
+    }
+
+}

algorithms-sorting-2/src/test/java/com/baeldung/algorithms/quicksort/DNFThreeWayQuickSortUnitTest.java

@@ -0,0 +1,15 @@
+package com.baeldung.algorithms.quicksort;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class DNFThreeWayQuickSortUnitTest {
+
+    @Test
+    public void givenIntegerArray_whenSortedWithThreeWayQuickSort_thenGetSortedArray() {
+        int[] actual = {3, 5, 5, 5, 3, 7, 7, 3, 5, 5, 7, 3, 3};
+        int[] expected = {3, 3, 3, 3, 3, 5, 5, 5, 5, 5, 7, 7, 7};
+        DutchNationalFlagPartioning.quicksort(actual, 0, actual.length - 1);
+        Assert.assertArrayEquals(expected, actual);
+    }
+}

apache-poi/pom.xml

@@ -32,7 +32,7 @@
     </dependencies>
 
     <properties>
-        <poi.version>3.15</poi.version>
+        <poi.version>4.1.1</poi.version>
         <jexcel.version>1.0.6</jexcel.version>
     </properties>
 

apache-poi/src/main/java/com/baeldung/poi/excel/ExcelCellFormatter.java

@@ -0,0 +1,20 @@
+package com.baeldung.poi.excel;
+
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.DataFormatter;
+import org.apache.poi.ss.usermodel.FormulaEvaluator;
+import org.apache.poi.ss.usermodel.Workbook;
+
+public class ExcelCellFormatter {
+
+    public String getCellStringValue(Cell cell) {
+        DataFormatter formatter = new DataFormatter();
+        return formatter.formatCellValue(cell);
+    }
+
+    public String getCellStringValueWithFormula(Cell cell, Workbook workbook) {
+        DataFormatter formatter = new DataFormatter();
+        FormulaEvaluator evaluator = workbook.getCreationHelper().createFormulaEvaluator();
+        return formatter.formatCellValue(cell, evaluator);
+    }
+}

apache-poi/src/main/java/com/baeldung/poi/excel/read/cellvalueandnotformula/CellValueAndNotFormulaHelper.java

@@ -0,0 +1,83 @@
+package com.baeldung.poi.excel.read.cellvalueandnotformula;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.CellType;
+import org.apache.poi.ss.usermodel.FormulaEvaluator;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.ss.util.CellAddress;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+
+public class CellValueAndNotFormulaHelper {
+
+    public Object getCellValueByFetchingLastCachedValue(String fileLocation, String cellLocation) throws IOException {
+        Object cellValue = new Object();
+
+        FileInputStream inputStream = new FileInputStream(new File(fileLocation));
+        Workbook workbook = new XSSFWorkbook(inputStream);
+
+        Sheet sheet = workbook.getSheetAt(0);
+
+        CellAddress cellAddress = new CellAddress(cellLocation);
+        Row row = sheet.getRow(cellAddress.getRow());
+        Cell cell = row.getCell(cellAddress.getColumn());
+
+        if (cell.getCellType() == CellType.FORMULA) {
+            switch (cell.getCachedFormulaResultType()) {
+                case BOOLEAN:
+                    cellValue = cell.getBooleanCellValue();
+                    break;
+                case NUMERIC:
+                    cellValue = cell.getNumericCellValue();
+                    break;
+                case STRING:
+                    cellValue = cell.getStringCellValue();
+                    break;
+                default:
+                    cellValue = null;
+            }
+        }
+
+        workbook.close();
+        return cellValue;
+    }
+
+    public Object getCellValueByEvaluatingFormula(String fileLocation, String cellLocation) throws IOException {
+        Object cellValue = new Object();
+
+        FileInputStream inputStream = new FileInputStream(new File(fileLocation));
+        Workbook workbook = new XSSFWorkbook(inputStream);
+
+        Sheet sheet = workbook.getSheetAt(0);
+        FormulaEvaluator evaluator = workbook.getCreationHelper()
+            .createFormulaEvaluator();
+
+        CellAddress cellAddress = new CellAddress(cellLocation);
+        Row row = sheet.getRow(cellAddress.getRow());
+        Cell cell = row.getCell(cellAddress.getColumn());
+
+        if (cell.getCellType() == CellType.FORMULA) {
+            switch (evaluator.evaluateFormulaCell(cell)) {
+                case BOOLEAN:
+                    cellValue = cell.getBooleanCellValue();
+                    break;
+                case NUMERIC:
+                    cellValue = cell.getNumericCellValue();
+                    break;
+                case STRING:
+                    cellValue = cell.getStringCellValue();
+                    break;
+                default:
+                    cellValue = null;
+            }
+        }
+
+        workbook.close();
+        return cellValue;
+    }
+}

apache-poi/src/test/java/com/baeldung/poi/excel/ExcelCellFormatterUnitTest.java

@@ -0,0 +1,87 @@
+package com.baeldung.poi.excel;
+
+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.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+import org.junit.Before;
+import org.junit.Test;
+
+public class ExcelCellFormatterUnitTest {
+    private static final String FILE_NAME = "ExcelCellFormatterTest.xlsx";
+    private static final int STRING_CELL_INDEX = 0;
+    private static final int BOOLEAN_CELL_INDEX = 1;
+    private static final int RAW_NUMERIC_CELL_INDEX = 2;
+    private static final int FORMATTED_NUMERIC_CELL_INDEX = 3;
+    private static final int FORMULA_CELL_INDEX = 4;
+
+    private String fileLocation;
+
+    @Before
+    public void setup() throws IOException, URISyntaxException {
+            fileLocation = Paths.get(ClassLoader.getSystemResource(FILE_NAME).toURI()).toString();
+    }
+
+    @Test
+    public void givenStringCell_whenGetCellStringValue_thenReturnStringValue() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(0);
+        Row row = sheet.getRow(0);
+
+        ExcelCellFormatter formatter = new ExcelCellFormatter();
+        assertEquals("String Test", formatter.getCellStringValue(row.getCell(STRING_CELL_INDEX)));
+        workbook.close();
+    }
+
+    @Test
+    public void givenBooleanCell_whenGetCellStringValue_thenReturnBooleanStringValue() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(0);
+        Row row = sheet.getRow(0);
+
+        ExcelCellFormatter formatter = new ExcelCellFormatter();
+        assertEquals("TRUE", formatter.getCellStringValue(row.getCell(BOOLEAN_CELL_INDEX)));
+        workbook.close();
+    }
+
+    @Test
+    public void givenNumericCell_whenGetCellStringValue_thenReturnNumericStringValue() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(0);
+        Row row = sheet.getRow(0);
+
+        ExcelCellFormatter formatter = new ExcelCellFormatter();
+        assertEquals("1.234", formatter.getCellStringValue(row.getCell(RAW_NUMERIC_CELL_INDEX)));
+        assertEquals("1.23", formatter.getCellStringValue(row.getCell(FORMATTED_NUMERIC_CELL_INDEX)));
+        workbook.close();
+    }
+
+    @Test
+    public void givenFormualCell_whenGetCellStringValue_thenReturnOriginalFormulaString() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(0);
+        Row row = sheet.getRow(0);
+
+        ExcelCellFormatter formatter = new ExcelCellFormatter();
+        assertEquals("SUM(1+2)", formatter.getCellStringValue(row.getCell(FORMULA_CELL_INDEX)));
+        workbook.close();
+    }
+
+    @Test
+    public void givenFormualCell_whenGetCellStringValueForFormula_thenReturnOriginalFormulatring() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(0);
+        Row row = sheet.getRow(0);
+
+        ExcelCellFormatter formatter = new ExcelCellFormatter();
+        assertEquals("3", formatter.getCellStringValueWithFormula(row.getCell(FORMULA_CELL_INDEX), workbook));
+        workbook.close();
+    }
+
+}

apache-poi/src/test/java/com/baeldung/poi/excel/read/cellvalueandnotformula/CellValueAndNotFormulaUnitTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.poi.excel.read.cellvalueandnotformula;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.Paths;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class CellValueAndNotFormulaUnitTest {
+
+    private CellValueAndNotFormulaHelper readCellValueAndNotFormulaHelper;
+    private String fileLocation;
+    private static final String FILE_NAME = "test.xlsx";
+
+    @Before
+    public void setup() throws URISyntaxException {
+        fileLocation = Paths.get(ClassLoader.getSystemResource(FILE_NAME).toURI()).toString();
+        readCellValueAndNotFormulaHelper = new CellValueAndNotFormulaHelper();
+    }
+
+    @Test
+    public void givenExcelCell_whenReadCellValueByLastCachedValue_thenProduceCorrectResult() throws IOException {
+        final double expectedResult = 7.0;
+        final Object cellValue = readCellValueAndNotFormulaHelper.getCellValueByFetchingLastCachedValue(fileLocation, "C2");
+
+        assertEquals(expectedResult, cellValue);
+    }
+
+    @Test
+    public void givenExcelCell_whenReadCellValueByEvaluatingFormula_thenProduceCorrectResult() throws IOException {
+        final double expectedResult = 7.0;
+        final Object cellValue = readCellValueAndNotFormulaHelper.getCellValueByEvaluatingFormula(fileLocation, "C2");
+
+        assertEquals(expectedResult, cellValue);
+    }
+}

apache-rocketmq/README.md

@@ -0,0 +1,5 @@
+## Apache RocketMQ
+
+This module contains articles about Apache RocketMQ
+
+### Relevant Articles: 

apache-rocketmq/pom.xml

@@ -0,0 +1,27 @@
+<?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>apache-rocketmq</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <name>apache-rocketmq</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.rocketmq</groupId>
+            <artifactId>rocketmq-spring-boot-starter</artifactId>
+            <version>2.0.4</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <geode.core>1.6.0</geode.core>
+    </properties>
+</project>

apache-rocketmq/src/main/java/com/baeldung/rocketmq/consumer/CartEventConsumer.java

@@ -0,0 +1,34 @@
+package com.baeldung.rocketmq.consumer;
+
+import com.baeldung.rocketmq.event.CartItemEvent;
+import org.apache.rocketmq.spring.annotation.RocketMQMessageListener;
+import org.apache.rocketmq.spring.core.RocketMQListener;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.stereotype.Service;
+
+@SpringBootApplication
+public class CartEventConsumer {
+
+    public static void main(String[] args) {
+        SpringApplication.run(CartEventConsumer.class, args);
+    }
+
+    @Service
+    @RocketMQMessageListener(topic = "cart-item-add-topic", consumerGroup = "cart-consumer_cart-item-add-topic")
+    public class CardItemAddConsumer implements RocketMQListener<CartItemEvent> {
+        public void onMessage(CartItemEvent addItemEvent) {
+            System.out.println("Adding item: " + addItemEvent);
+            // logic
+        }
+    }
+
+    @Service
+    @RocketMQMessageListener(topic = "cart-item-removed-topic", consumerGroup = "cart-consumer_cart-item-removed-topic")
+    public class CardItemRemoveConsumer implements RocketMQListener<CartItemEvent> {
+        public void onMessage(CartItemEvent removeItemEvent) {
+            System.out.println("Removing item: " + removeItemEvent);
+            // logic
+        }
+    }
+}

apache-rocketmq/src/main/java/com/baeldung/rocketmq/event/CartItemEvent.java

@@ -0,0 +1,32 @@
+package com.baeldung.rocketmq.event;
+
+public class CartItemEvent {
+    private String itemId;
+    private int quantity;
+
+    public CartItemEvent(String itemId, int quantity) {
+        this.itemId = itemId;
+        this.quantity = quantity;
+    }
+
+    public String getItemId() {
+        return itemId;
+    }
+
+    public void setItemId(String itemId) {
+        this.itemId = itemId;
+    }
+
+    public int getQuantity() {
+        return quantity;
+    }
+
+    public void setQuantity(int quantity) {
+        this.quantity = quantity;
+    }
+
+    @Override
+    public String toString() {
+        return "CartItemEvent{" + "itemId='" + itemId + '\'' + ", quantity=" + quantity + '}';
+    }
+}

apache-rocketmq/src/main/java/com/baeldung/rocketmq/producer/CartEventProducer.java

@@ -0,0 +1,26 @@
+package com.baeldung.rocketmq.producer;
+
+
+import com.baeldung.rocketmq.event.CartItemEvent;
+import org.apache.rocketmq.spring.core.RocketMQTemplate;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class CartEventProducer implements CommandLineRunner {
+
+    @Autowired
+    private RocketMQTemplate rocketMQTemplate;
+
+    public static void main(String[] args) {
+        SpringApplication.run(CartEventProducer.class, args);
+    }
+
+    public void run(String... args) throws Exception {
+        rocketMQTemplate.convertAndSend("cart-item-add-topic", new CartItemEvent("bike", 1));
+        rocketMQTemplate.convertAndSend("cart-item-add-topic", new CartItemEvent("computer", 2));
+        rocketMQTemplate.convertAndSend("cart-item-removed-topic", new CartItemEvent("bike", 1));
+    }
+}

apache-rocketmq/src/main/java/com/baeldung/rocketmq/transaction/TransactionListenerImpl.java

@@ -0,0 +1,21 @@
+package com.baeldung.rocketmq.transaction;
+
+import org.apache.rocketmq.spring.annotation.RocketMQTransactionListener;
+import org.apache.rocketmq.spring.core.RocketMQLocalTransactionListener;
+import org.apache.rocketmq.spring.core.RocketMQLocalTransactionState;
+import org.springframework.messaging.Message;
+
+@RocketMQTransactionListener(txProducerGroup = "test-transaction")
+class TransactionListenerImpl implements RocketMQLocalTransactionListener {
+    @Override
+    public RocketMQLocalTransactionState executeLocalTransaction(Message msg, Object arg) {
+        // ... local transaction process, return ROLLBACK, COMMIT or UNKNOWN
+        return RocketMQLocalTransactionState.UNKNOWN;
+    }
+
+    @Override
+    public RocketMQLocalTransactionState checkLocalTransaction(Message msg) {
+        // ... check transaction status and return ROLLBACK, COMMIT or UNKNOWN
+        return RocketMQLocalTransactionState.COMMIT;
+    }
+}

apache-rocketmq/src/main/resources/application.properties

@@ -0,0 +1,9 @@
+rocketmq.name-server=127.0.0.1:9876
+rocketmq.producer.group=my-group
+rocketmq.producer.send-message-timeout=300000
+rocketmq.producer.compress-message-body-threshold=4096
+rocketmq.producer.max-message-size=4194304
+rocketmq.producer.retry-times-when-send-async-failed=0
+rocketmq.producer.retry-next-server=true
+rocketmq.producer.retry-times-when-send-failed=2
+

core-groovy-2/src/main/groovy/com/baeldung/metaprogramming/extension/BasicExtensions.groovy

@@ -2,10 +2,13 @@ package com.baeldung.metaprogramming.extension
 
 import com.baeldung.metaprogramming.Employee
 
+import java.time.LocalDate
+import java.time.Year
+
 class BasicExtensions {
     
     static int getYearOfBirth(Employee self) {
-        return (new Date().getYear() + 1900) - self.age;
+        return Year.now().value - self.age
     }
     
     static String capitalize(String self) {

core-groovy-2/src/test/groovy/com/baeldung/metaprogramming/MetaprogrammingUnitTest.groovy

@@ -1,6 +1,9 @@
 package com.baeldung.metaprogramming
 
-import groovy.time.TimeCategory
+
+import java.time.LocalDate
+import java.time.Period
+import java.time.Year
 
 class MetaprogrammingUnitTest extends GroovyTestCase {
 
@@ -51,15 +54,17 @@ class MetaprogrammingUnitTest extends GroovyTestCase {
 
     void testJavaMetaClass() {
         String.metaClass.capitalize = { String str ->
-            str.substring(0, 1).toUpperCase() + str.substring(1);
+            str.substring(0, 1).toUpperCase() + str.substring(1)
         }
         assert "norman".capitalize() == "Norman"
     }
 
-//    void testEmployeeExtension() {
-//        Employee emp = new Employee(age: 28)
-//        assert emp.getYearOfBirth() == 1991
-//    }
+    void testEmployeeExtension() {
+        def age = 28
+        def expectedYearOfBirth = Year.now() - age
+        Employee emp = new Employee(age: age)
+        assert emp.getYearOfBirth() == expectedYearOfBirth.value
+    }
 
     void testJavaClassesExtensions() {
         5.printCounter()
@@ -115,4 +120,4 @@ class MetaprogrammingUnitTest extends GroovyTestCase {
         Employee employee = new Employee(1, "Norman", "Lewis", 28)
         employee.logEmp()
     }
-}
+}

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

@@ -75,6 +75,7 @@ class WebserviceManualTest 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)
@@ -89,6 +90,7 @@ class WebserviceManualTest extends GroovyTestCase {
         def words = response.NumberToWordsResponse
         assert words == "one thousand two hundred and thirty four "
     }
+    */
 
     void test_whenConsumingRestGet_thenReceiveResponse() {
         def path = "/get"
@@ -149,4 +151,4 @@ class WebserviceManualTest extends GroovyTestCase {
             assert e?.response?.statusCode != 200
         }
     }
-}
+}

core-java-lambdas/README.md

@@ -1,2 +0,0 @@
-### Relevant Articles:
-- [Java 9 java.lang.Module API](https://www.baeldung.com/java-lambda-effectively-final-local-variables)

core-java-modules/core-java-14/pom.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.baeldung</groupId>
+	<artifactId>core-java-14</artifactId>
+	<version>1.0.0-SNAPSHOT</version>
+	<name>core-java-14</name>
+	<packaging>jar</packaging>
+	<url>http://maven.apache.org</url>
+
+	<parent>
+		<groupId>com.baeldung</groupId>
+		<artifactId>parent-modules</artifactId>
+		<version>1.0.0-SNAPSHOT</version>
+		<relativePath>../../</relativePath>
+	</parent>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>${maven-compiler-plugin.version}</version>
+				<configuration>
+					<source>${maven.compiler.source.version}</source>
+					<target>${maven.compiler.target.version}</target>
+					<compilerArgs>
+						<compilerArg>
+							--enable-preview
+						</compilerArg>
+					</compilerArgs>
+				</configuration>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<version>3.0.0-M3</version>
+				<configuration>
+					<argLine>--enable-preview</argLine>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+	<properties>
+		<maven.compiler.source.version>14</maven.compiler.source.version>
+		<maven.compiler.target.version>14</maven.compiler.target.version>
+	</properties>
+
+</project>

core-java-modules/core-java-14/src/main/java/com/baeldung/serial/MySerialClass.java

@@ -0,0 +1,50 @@
+package com.baeldung.serial;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.ObjectStreamException;
+import java.io.ObjectStreamField;
+import java.io.Serial;
+import java.io.Serializable;
+
+/**
+ * Class showcasing the usage of the Java 14 @Serial annotation.
+ * 
+ * @author Donato Rimenti
+ */
+public class MySerialClass implements Serializable {
+	
+	@Serial
+	private static final ObjectStreamField[] serialPersistentFields = null;
+	
+	@Serial
+	private static final long serialVersionUID = 1;
+
+	@Serial
+	private void writeObject(ObjectOutputStream stream) throws IOException {
+		// ...
+	}
+
+	@Serial
+	private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
+		// ...
+	}
+
+	@Serial
+	private void readObjectNoData() throws ObjectStreamException {
+		// ...
+	}
+
+	@Serial
+	private Object writeReplace() throws ObjectStreamException {
+		// ...
+		return null;
+	}
+
+	@Serial
+	private Object readResolve() throws ObjectStreamException {
+		// ...
+		return null;
+	}
+}

core-java-modules/core-java-arrays-2/pom.xml

@@ -19,6 +19,16 @@
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
             <version>${commons-lang3.version}</version>
+        </dependency>
+		<dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${jmh.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${jmh.version}</version>
         </dependency>
         <!-- test scoped -->
         <dependency>
@@ -37,9 +47,34 @@
                 <filtering>true</filtering>
             </resource>
         </resources>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-shade-plugin</artifactId>
+				<version>3.2.0</version>
+				<executions>
+					<execution>
+						<phase>package</phase>
+						<goals>
+							<goal>shade</goal>
+						</goals>
+						<configuration>
+							<finalName>benchmarks</finalName>
+							<transformers>
+								<transformer
+										implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+									<mainClass>org.openjdk.jmh.Main</mainClass>
+								</transformer>
+							</transformers>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
     </build>
 
     <properties>
+		<jmh.version>1.19</jmh.version>
         <!-- util -->
         <commons-lang3.version>3.9</commons-lang3.version>
         <!-- testing -->

core-java-modules/core-java-arrays-2/src/main/java/com/baeldung/arraysort/ArraySortingBenchmark.java

@@ -0,0 +1,72 @@
+package com.baeldung.arraysort;
+
+import java.util.Arrays;
+import java.util.Random;
+import java.util.concurrent.TimeUnit;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Level;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+@BenchmarkMode(Mode.AverageTime)
+@Warmup(iterations = 5)
+@Measurement(iterations = 10)
+@Fork(2)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+public class ArraySortingBenchmark {
+
+    @State(Scope.Benchmark)
+    public static class ArrayContainer {
+
+        @Param({ "1000", "10000", "100000", "1000000" })
+        int arraySize;
+
+        // initial unsorted array
+        int[] unsortedArray;
+        
+        //cloned array to sort
+        int[] arrayToSort;
+
+        @Setup(Level.Trial)
+        public void createUnSortedArray() {
+            unsortedArray = new int[arraySize];
+            for (int i = 0; i < arraySize; i++) {
+                unsortedArray[i] = new Random().nextInt(1000);
+            }
+        }
+
+        @Setup(Level.Invocation)
+        public void createUnSortedArrayCopy() {
+            arrayToSort = unsortedArray.clone();
+        }
+
+        int[] getArrayToSort() {
+            return arrayToSort;
+        }
+    }
+
+    @Benchmark
+    public void benchmark_arrays_parallel_sort(ArrayContainer d, Blackhole b) {
+        int[] arr = d.getArrayToSort();
+        Arrays.parallelSort(arr);
+        b.consume(arr);
+    }
+
+    @Benchmark
+    public void benchmark_arrays_sort(ArrayContainer d, Blackhole b) {
+        int[] arr = d.getArrayToSort();
+        Arrays.sort(arr);
+        b.consume(arr);
+    }
+
+}

core-java-modules/core-java-collections-list-3/src/main/java/com/baeldung/list/duplicatescounter/DuplicatesCounter.java

@@ -24,11 +24,21 @@ public class DuplicatesCounter {
         return resultMap;
     }
 
-    public static <T> Map<T, Long> countByClassicalLoopWithMapCompute(List<T> inputList) {
+    public static <T> Map<T, Long> countByForEachLoopWithGetOrDefault(List<T> inputList) {
         Map<T, Long> resultMap = new HashMap<>();
-        for (T element : inputList) {
-            resultMap.compute(element, (k, v) -> v == null ? 1 : v + 1);
-        }
+        inputList.forEach(e -> resultMap.put(e, resultMap.getOrDefault(e, 0L) + 1L));
+        return resultMap;
+    }
+
+    public static <T> Map<T, Long> countByForEachLoopWithMapCompute(List<T> inputList) {
+        Map<T, Long> resultMap = new HashMap<>();
+        inputList.forEach(e -> resultMap.compute(e, (k, v) -> v == null ? 1L : v + 1L));
+        return resultMap;
+    }
+
+    public static <T> Map<T, Long> countByForEachLoopWithMapMerge(List<T> inputList) {
+        Map<T, Long> resultMap = new HashMap<>();
+        inputList.forEach(e -> resultMap.merge(e, 1L, Long::sum));
         return resultMap;
     }
 

core-java-modules/core-java-collections-list-3/src/test/java/com/baeldung/list/duplicatescounter/DuplicatesCounterUnitTest.java

@@ -11,7 +11,6 @@ import static org.assertj.core.data.MapEntry.entry;
 
 class DuplicatesCounterUnitTest {
 
-
     private static List<String> INPUT_LIST = Lists.list(
         "expect1",
         "expect2", "expect2",
@@ -24,10 +23,21 @@ class DuplicatesCounterUnitTest {
         verifyResult(result);
     }
 
+    @Test
+    void givenInput_whenCountByForEachLoopWithGetOrDefault_thenGetResultMap() {
+        Map<String, Long> result = DuplicatesCounter.countByForEachLoopWithGetOrDefault(INPUT_LIST);
+        verifyResult(result);
+    }
 
     @Test
-    void givenInput_whenCountByClassicalLoopWithMapCompute_thenGetResultMap() {
-        Map<String, Long> result = DuplicatesCounter.countByClassicalLoopWithMapCompute(INPUT_LIST);
+    void givenInput_whenCountByForEachLoopWithMapCompute_thenGetResultMap() {
+        Map<String, Long> result = DuplicatesCounter.countByForEachLoopWithMapCompute(INPUT_LIST);
+        verifyResult(result);
+    }
+
+    @Test
+    void givenInput_whenCountByForEachLoopWithMapMerge_thenGetResultMap() {
+        Map<String, Long> result = DuplicatesCounter.countByForEachLoopWithMapMerge(INPUT_LIST);
         verifyResult(result);
     }
 

core-java-modules/core-java-concurrency-advanced-3/pom.xml

@@ -23,6 +23,37 @@
             <version>${assertj.version}</version>
             <scope>test</scope>
         </dependency>
+        
+        <dependency>
+            <groupId>com.jcabi</groupId>
+            <artifactId>jcabi-aspects</artifactId>
+            <version>${jcabi-aspects.version}</version>
+        </dependency>
+        
+        <dependency>
+            <groupId>org.aspectj</groupId>
+            <artifactId>aspectjrt</artifactId>
+            <version>${aspectjrt.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+        
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
+        
+        <dependency>
+            <groupId>org.cactoos</groupId>
+            <artifactId>cactoos</artifactId>
+            <version>${cactoos.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.ea.async</groupId>
+            <artifactId>ea-async</artifactId>
+            <version>${ea-async.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -36,6 +67,30 @@
                     <target>${maven.compiler.target}</target>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>com.jcabi</groupId>
+                <artifactId>jcabi-maven-plugin</artifactId>
+                <version>${jcabi-maven-plugin.version}</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>ajc</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.aspectj</groupId>
+                        <artifactId>aspectjtools</artifactId>
+                        <version>${aspectjtools.version}</version>
+                    </dependency>
+                    <dependency>
+                        <groupId>org.aspectj</groupId>
+                        <artifactId>aspectjweaver</artifactId>
+                        <version>${aspectjweaver.version}</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
         </plugins>
         <resources>
             <resource>
@@ -49,6 +104,14 @@
         <assertj.version>3.14.0</assertj.version>
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
+        <jcabi-aspects.version>0.22.6</jcabi-aspects.version>
+        <aspectjrt.version>1.9.5</aspectjrt.version>
+        <guava.version>28.2-jre</guava.version>
+        <cactoos.version>0.43</cactoos.version>
+        <ea-async.version>1.2.3</ea-async.version>
+        <jcabi-maven-plugin.version>0.14.1</jcabi-maven-plugin.version>
+        <aspectjtools.version>1.9.1</aspectjtools.version>
+        <aspectjweaver.version>1.9.1</aspectjweaver.version>
     </properties>
 
 </project>

core-java-modules/core-java-concurrency-advanced-3/src/main/java/com/baeldung/async/EAAsyncExample.java

@@ -0,0 +1,57 @@
+package com.baeldung.async;
+
+import static com.ea.async.Async.await;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+
+import com.ea.async.Async;
+
+public class EAAsyncExample {
+
+    static {
+        Async.init();
+    }
+
+    public static void main(String[] args) throws Exception {
+        usingCompletableFuture();
+        usingAsyncAwait();
+    }
+
+    public static void usingCompletableFuture() throws InterruptedException, ExecutionException, Exception {
+        CompletableFuture<Void> completableFuture = hello()
+            .thenComposeAsync(hello -> mergeWorld(hello))
+            .thenAcceptAsync(helloWorld -> print(helloWorld))
+            .exceptionally( throwable -> {
+                System.out.println(throwable.getCause()); 
+                return null;
+            });
+        completableFuture.get();
+    }
+
+    public static CompletableFuture<String> hello() {
+        CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> "Hello");
+        return completableFuture;
+    }
+
+    public static CompletableFuture<String> mergeWorld(String s) {
+        CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> {
+            return s + " World!";
+        });
+        return completableFuture;
+    }
+
+    public static void print(String str) {
+        CompletableFuture.runAsync(() -> System.out.println(str));
+    }
+
+    private static void usingAsyncAwait() {
+        try {
+            String hello = await(hello());
+            String helloWorld = await(mergeWorld(hello));
+            await(CompletableFuture.runAsync(() -> print(helloWorld)));
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+}

core-java-modules/core-java-concurrency-advanced-3/src/main/java/com/baeldung/async/JavaAsync.java

@@ -0,0 +1,183 @@
+package com.baeldung.async;
+
+import static com.ea.async.Async.await;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+import com.google.common.util.concurrent.AsyncCallable;
+import com.google.common.util.concurrent.Callables;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.ListeningExecutorService;
+import com.google.common.util.concurrent.MoreExecutors;
+import com.jcabi.aspects.Async;
+import com.jcabi.aspects.Loggable;
+
+public class JavaAsync {
+
+    static {
+        com.ea.async.Async.init();
+    }
+
+    private static final ExecutorService threadpool = Executors.newCachedThreadPool();
+
+    public static void main (String[] args) throws InterruptedException, ExecutionException {
+        int number = 20;
+
+        //Thread Example
+        factorialUsingThread(number).start();
+
+        //FutureTask Example
+        Future<Long> futureTask = factorialUsingFutureTask(number);
+        System.out.println("Factorial of " + number + " is: " + futureTask.get());
+
+        // CompletableFuture Example
+        Future<Long> completableFuture = factorialUsingCompletableFuture(number);
+        System.out.println("Factorial of " + number + " is: " + completableFuture.get());
+
+        // EA Async example
+        System.out.println("Factorial of " + number + " is: " + factorialUsingEAAsync(number));
+
+        // cactoos async example
+        Future<Long> asyncFuture = factorialUsingCactoos(number);
+        System.out.println("Factorial of " + number + " is: " + asyncFuture.get());
+
+        // Guava example
+        ListenableFuture<Long> guavaFuture = factorialUsingGuavaServiceSubmit(number);
+        System.out.println("Factorial of " + number + " is: " + guavaFuture.get());
+
+        ListenableFuture<Long> guavaFutures = factorialUsingGuavaFutures(number);
+        System.out.println("Factorial of " + number + " is: " + guavaFutures.get());
+
+        // @async jcabi-aspect example
+        Future<Long> aspectFuture = factorialUsingJcabiAspect(number);
+        System.out.println("Factorial of " + number + " is: " + aspectFuture.get());
+
+    }
+
+    /**
+     * Finds factorial of a number
+     * @param number
+     * @return
+     */
+    public static long factorial(int number) {
+        long result = 1; 
+        for(int i=number;i>0;i--) {
+            result *= i; 
+        } 
+        return result; 
+    }
+
+    /**
+     * Finds factorial of a number using Thread
+     * @param number
+     * @return
+     */
+    @Loggable
+    public static Thread factorialUsingThread(int number) {
+        Thread newThread = new Thread(() -> {
+            System.out.println("Factorial of " + number + " is: " + factorial(number));
+        });
+
+        return newThread;
+    }
+
+    /**
+     * Finds factorial of a number using FutureTask
+     * @param number
+     * @return
+     */
+    @Loggable
+    public static Future<Long> factorialUsingFutureTask(int number) {
+        Future<Long> futureTask = threadpool.submit(() -> factorial(number)); 
+
+        while (!futureTask.isDone()) { 
+            System.out.println("FutureTask is not finished yet..."); 
+        } 
+
+        return futureTask;
+    }
+
+    /**
+     * Finds factorial of a number using CompletableFuture
+     * @param number
+     * @return
+     */
+    @Loggable
+    public static Future<Long> factorialUsingCompletableFuture(int number) {
+        CompletableFuture<Long> completableFuture = CompletableFuture.supplyAsync(() -> factorial(number));
+        return completableFuture;
+    }
+
+    /**
+     * Finds factorial of a number using EA Async
+     * @param number
+     * @return
+     */
+    @Loggable
+    public static long factorialUsingEAAsync(int number) {
+        CompletableFuture<Long> completableFuture = CompletableFuture.supplyAsync(() -> factorial(number));
+        long result = await(completableFuture);
+        return result;
+    }
+
+    /**
+     * Finds factorial of a number using Async of Cactoos
+     * @param number
+     * @return
+     * @throws InterruptedException
+     * @throws ExecutionException
+     */
+    @Loggable
+    public static Future<Long> factorialUsingCactoos(int number) throws InterruptedException, ExecutionException {
+        org.cactoos.func.Async<Integer, Long> asyncFunction = new org.cactoos.func.Async<Integer, Long>(input -> factorial(input));
+        Future<Long> asyncFuture = asyncFunction.apply(number);
+        return asyncFuture;
+    }
+
+    /**
+     * Finds factorial of a number using Guava's ListeningExecutorService.submit()
+     * @param number
+     * @return
+     */
+    @Loggable
+    public static ListenableFuture<Long> factorialUsingGuavaServiceSubmit(int number) {
+        ListeningExecutorService service = MoreExecutors.listeningDecorator(threadpool);
+        ListenableFuture<Long> factorialFuture = (ListenableFuture<Long>) service.submit(()-> factorial(number));
+        return factorialFuture;
+    }
+
+    /**
+     * Finds factorial of a number using Guava's Futures.submitAsync()
+     * @param number
+     * @return
+     */
+    @Loggable
+    public static ListenableFuture<Long> factorialUsingGuavaFutures(int number) {
+        ListeningExecutorService service = MoreExecutors.listeningDecorator(threadpool);
+        AsyncCallable<Long> asyncCallable = Callables.asAsyncCallable(new Callable<Long>() {
+            public Long call() {
+                return factorial(number);
+            }
+        }, service);
+        return Futures.submitAsync(asyncCallable, service);
+    }
+
+    /**
+     * Finds factorial of a number using @Async of jcabi-aspects
+     * @param number
+     * @return
+     */
+    @Async
+    @Loggable
+    public static Future<Long> factorialUsingJcabiAspect(int number) {
+        Future<Long> factorialFuture = CompletableFuture.supplyAsync(() -> factorial(number));
+        return factorialFuture;
+    }
+
+}

core-java-modules/core-java-date-operations-1/README.md

@@ -1,6 +1,5 @@
-## Java Date/time computations Cookbooks and Examples
-
-This module contains articles about date and time computations in Java.
+## Core Date Operations (Part 1)
+This module contains articles about date operations in Java.
 
 ### Relevant Articles: 
 - [Difference Between Two Dates in Java](http://www.baeldung.com/java-date-difference)
@@ -13,3 +12,4 @@ This module contains articles about date and time computations in Java.
 - [Increment Date in Java](http://www.baeldung.com/java-increment-date)
 - [Add Hours To a Date In Java](http://www.baeldung.com/java-add-hours-date)
 - [Introduction to Joda-Time](http://www.baeldung.com/joda-time)
+- [[Next -->]](/core-java-modules/core-java-date-operations-2)

core-java-modules/core-java-date-operations-1/pom.xml

@@ -2,9 +2,9 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-    <artifactId>core-java-datetime-computations</artifactId>
+    <artifactId>core-java-date-operations-1</artifactId>
     <version>${project.parent.version}</version>
-    <name>core-java-datetime-computations</name>
+    <name>core-java-date-operations-1</name>
     <packaging>jar</packaging>
 
     <parent>
@@ -41,7 +41,7 @@
     </dependencies>
 
     <build>
-        <finalName>core-java-datetime-computations</finalName>
+        <finalName>core-java-date-operations-1</finalName>
         <resources>
             <resource>
                 <directory>src/main/resources</directory>

core-java-modules/core-java-date-operations-2/README.md

@@ -1,4 +1,4 @@
-## Core Date Operations
+## Core Date Operations (Part 2)
 This module contains articles about date operations in Java.
 
 ### Relevant Articles:
@@ -6,3 +6,4 @@ This module contains articles about date operations in Java.
 - [Skipping Weekends While Adding Days to LocalDate in Java 8](https://www.baeldung.com/java-localdate-add-days-skip-weekends)
 - [Checking If Two Java Dates Are on the Same Day](https://www.baeldung.com/java-check-two-dates-on-same-day)
 - [Converting Java Date to OffsetDateTime](https://www.baeldung.com/java-convert-date-to-offsetdatetime)
+- [[<-- Prev]](/core-java-modules/core-java-date-operations-1)

core-java-modules/core-java-date-operations-2/pom.xml

@@ -3,9 +3,9 @@
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-    <artifactId>core-java-date-operations</artifactId>
+    <artifactId>core-java-date-operations-2</artifactId>
     <version>${project.parent.version}</version>
-    <name>core-java-date-operations</name>
+    <name>core-java-date-operations-2</name>
     <packaging>jar</packaging>
 
     <parent>
@@ -31,11 +31,18 @@
             <artifactId>hirondelle-date4j</artifactId>
             <version>${hirondelle-date4j.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <properties>
         <joda-time.version>2.10</joda-time.version>
         <hirondelle-date4j.version>1.5.1</hirondelle-date4j.version>
+        <assertj.version>3.14.0</assertj.version>
     </properties>
 
 </project>

core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/date/comparison/DateComparisonUtils.java

@@ -1,55 +1,65 @@
-package com.baeldung.date.comparison;
-
-import java.text.SimpleDateFormat;
-import java.time.LocalDate;
-import java.time.ZoneId;
-import java.util.Calendar;
-import java.util.Date;
-import java.util.TimeZone;
-
-import org.apache.commons.lang3.time.DateUtils;
-
-import hirondelle.date4j.DateTime;
-
-public class DateComparisonUtils {
-
-    public static boolean isSameDayUsingLocalDate(Date date1, Date date2) {
-        LocalDate localDate1 = date1.toInstant()
-            .atZone(ZoneId.systemDefault())
-            .toLocalDate();
-        LocalDate localDate2 = date2.toInstant()
-            .atZone(ZoneId.systemDefault())
-            .toLocalDate();
-        return localDate1.isEqual(localDate2);
-    }
-
-    public static boolean isSameDayUsingSimpleDateFormat(Date date1, Date date2) {
-        SimpleDateFormat fmt = new SimpleDateFormat("yyyyMMdd");
-        return fmt.format(date1)
-            .equals(fmt.format(date2));
-    }
-
-    public static boolean isSameDayUsingCalendar(Date date1, Date date2) {
-        Calendar calendar1 = Calendar.getInstance();
-        calendar1.setTime(date1);
-        Calendar calendar2 = Calendar.getInstance();
-        calendar2.setTime(date2);
-        return calendar1.get(Calendar.YEAR) == calendar2.get(Calendar.YEAR) && calendar1.get(Calendar.MONTH) == calendar2.get(Calendar.MONTH) && calendar1.get(Calendar.DAY_OF_MONTH) == calendar2.get(Calendar.DAY_OF_MONTH);
-    }
-
-    public static boolean isSameDayUsingApacheCommons(Date date1, Date date2) {
-        return DateUtils.isSameDay(date1, date2);
-    }
-
-    public static boolean isSameDayUsingJoda(Date date1, Date date2) {
-        org.joda.time.LocalDate localDate1 = new org.joda.time.LocalDate(date1);
-        org.joda.time.LocalDate localDate2 = new org.joda.time.LocalDate(date2);
-        return localDate1.equals(localDate2);
-    }
-
-    public static boolean isSameDayUsingDate4j(Date date1, Date date2) {
-        DateTime dateObject1 = DateTime.forInstant(date1.getTime(), TimeZone.getDefault());
-        DateTime dateObject2 = DateTime.forInstant(date2.getTime(), TimeZone.getDefault());
-        return dateObject1.isSameDayAs(dateObject2);
-    }
-}
+package com.baeldung.date.comparison;
+
+import java.text.SimpleDateFormat;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.ZoneId;
+import java.time.temporal.ChronoUnit;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.TimeZone;
+
+import org.apache.commons.lang3.time.DateUtils;
+
+import hirondelle.date4j.DateTime;
+
+public class DateComparisonUtils {
+
+    public static boolean isSameDayUsingLocalDate(Date date1, Date date2) {
+        LocalDate localDate1 = date1.toInstant()
+            .atZone(ZoneId.systemDefault())
+            .toLocalDate();
+        LocalDate localDate2 = date2.toInstant()
+            .atZone(ZoneId.systemDefault())
+            .toLocalDate();
+        return localDate1.isEqual(localDate2);
+    }
+
+    public static boolean isSameDayUsingInstant(Date date1, Date date2) {
+        Instant instant1 = date1.toInstant()
+            .truncatedTo(ChronoUnit.DAYS);
+        Instant instant2 = date2.toInstant()
+            .truncatedTo(ChronoUnit.DAYS);
+        return instant1.equals(instant2);
+    }
+
+    public static boolean isSameDayUsingSimpleDateFormat(Date date1, Date date2) {
+        SimpleDateFormat fmt = new SimpleDateFormat("yyyyMMdd");
+        return fmt.format(date1)
+            .equals(fmt.format(date2));
+    }
+
+    public static boolean isSameDayUsingCalendar(Date date1, Date date2) {
+        Calendar calendar1 = Calendar.getInstance();
+        calendar1.setTime(date1);
+        Calendar calendar2 = Calendar.getInstance();
+        calendar2.setTime(date2);
+        return calendar1.get(Calendar.YEAR) == calendar2.get(Calendar.YEAR) && calendar1.get(Calendar.MONTH) == calendar2.get(Calendar.MONTH) && calendar1.get(Calendar.DAY_OF_MONTH) == calendar2.get(Calendar.DAY_OF_MONTH);
+    }
+
+    public static boolean isSameDayUsingApacheCommons(Date date1, Date date2) {
+        return DateUtils.isSameDay(date1, date2);
+    }
+
+    public static boolean isSameDayUsingJoda(Date date1, Date date2) {
+        org.joda.time.LocalDate localDate1 = new org.joda.time.LocalDate(date1);
+        org.joda.time.LocalDate localDate2 = new org.joda.time.LocalDate(date2);
+        return localDate1.equals(localDate2);
+    }
+
+    public static boolean isSameDayUsingDate4j(Date date1, Date date2) {
+        DateTime dateObject1 = DateTime.forInstant(date1.getTime(), TimeZone.getDefault());
+        DateTime dateObject2 = DateTime.forInstant(date2.getTime(), TimeZone.getDefault());
+        return dateObject1.isSameDayAs(dateObject2);
+    }
+}

core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/timer/DatabaseMigrationTask.java

@@ -0,0 +1,19 @@
+package com.baeldung.timer;
+
+import java.util.List;
+import java.util.TimerTask;
+
+public class DatabaseMigrationTask extends TimerTask {
+    private List<String> oldDatabase;
+    private List<String> newDatabase;
+
+    public DatabaseMigrationTask(List<String> oldDatabase, List<String> newDatabase) {
+        this.oldDatabase = oldDatabase;
+        this.newDatabase = newDatabase;
+    }
+
+    @Override
+    public void run() {
+        newDatabase.addAll(oldDatabase);
+    }
+}

core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/timer/NewsletterTask.java

@@ -0,0 +1,14 @@
+package com.baeldung.timer;
+
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.TimerTask;
+
+public class NewsletterTask extends TimerTask {
+    @Override
+    public void run() {
+        System.out.println("Email sent at: "
+          + LocalDateTime.ofInstant(Instant.ofEpochMilli(scheduledExecutionTime()), ZoneId.systemDefault()));
+    }
+}

core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/date/comparison/DateComparisonUtilsUnitTest.java

@@ -1,53 +1,57 @@
-package com.baeldung.date.comparison;
-
-import org.junit.Test;
-
-import java.time.LocalDateTime;
-import java.time.ZoneId;
-import java.util.Date;
-
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-public class DateComparisonUtilsUnitTest {
-
-    private Date day1Morning = toDate(LocalDateTime.of(2019, 10, 19, 6, 30, 40));
-    private Date day1Evening = toDate(LocalDateTime.of(2019, 10, 19, 18, 30, 50));
-    private Date day2Morning = toDate(LocalDateTime.of(2019, 10, 20, 6, 30, 50));
-
-    private Date toDate(LocalDateTime localDateTime) {
-        return Date.from(localDateTime.atZone(ZoneId.systemDefault())
-            .toInstant());
-    }
-
-    @Test
-    public void givenDatesWithDifferentTime_whenIsSameDay_thenReturnsTrue() {
-        assertTrue(DateComparisonUtils.isSameDayUsingLocalDate(day1Morning, day1Evening));
-        assertTrue(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Morning, day1Evening));
-        assertTrue(DateComparisonUtils.isSameDayUsingCalendar(day1Morning, day1Evening));
-        assertTrue(DateComparisonUtils.isSameDayUsingApacheCommons(day1Morning, day1Evening));
-        assertTrue(DateComparisonUtils.isSameDayUsingJoda(day1Morning, day1Evening));
-        assertTrue(DateComparisonUtils.isSameDayUsingDate4j(day1Morning, day1Evening));
-    }
-
-    @Test
-    public void givenDates_whenIsDifferentDay_thenReturnsFalse() {
-        assertFalse(DateComparisonUtils.isSameDayUsingLocalDate(day1Morning, day2Morning));
-        assertFalse(DateComparisonUtils.isSameDayUsingLocalDate(day1Evening, day2Morning));
-
-        assertFalse(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Morning, day2Morning));
-        assertFalse(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Evening, day2Morning));
-
-        assertFalse(DateComparisonUtils.isSameDayUsingCalendar(day1Morning, day2Morning));
-        assertFalse(DateComparisonUtils.isSameDayUsingCalendar(day1Evening, day2Morning));
-
-        assertFalse(DateComparisonUtils.isSameDayUsingApacheCommons(day1Morning, day2Morning));
-        assertFalse(DateComparisonUtils.isSameDayUsingApacheCommons(day1Evening, day2Morning));
-
-        assertFalse(DateComparisonUtils.isSameDayUsingJoda(day1Morning, day2Morning));
-        assertFalse(DateComparisonUtils.isSameDayUsingJoda(day1Evening, day2Morning));
-
-        assertFalse(DateComparisonUtils.isSameDayUsingDate4j(day1Morning, day2Morning));
-        assertFalse(DateComparisonUtils.isSameDayUsingDate4j(day1Evening, day2Morning));
-    }
-}
+package com.baeldung.date.comparison;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.Date;
+
+import org.junit.Test;
+
+public class DateComparisonUtilsUnitTest {
+
+    private Date day1Morning = toDate(LocalDateTime.of(2019, 10, 19, 6, 30, 40));
+    private Date day1Evening = toDate(LocalDateTime.of(2019, 10, 19, 18, 30, 50));
+    private Date day2Morning = toDate(LocalDateTime.of(2019, 10, 20, 6, 30, 50));
+
+    private Date toDate(LocalDateTime localDateTime) {
+        return Date.from(localDateTime.atZone(ZoneId.systemDefault())
+            .toInstant());
+    }
+
+    @Test
+    public void givenDatesWithDifferentTime_whenIsSameDay_thenReturnsTrue() {
+        assertTrue(DateComparisonUtils.isSameDayUsingLocalDate(day1Morning, day1Evening));
+        assertTrue(DateComparisonUtils.isSameDayUsingInstant(day1Morning, day1Evening));
+        assertTrue(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Morning, day1Evening));
+        assertTrue(DateComparisonUtils.isSameDayUsingCalendar(day1Morning, day1Evening));
+        assertTrue(DateComparisonUtils.isSameDayUsingApacheCommons(day1Morning, day1Evening));
+        assertTrue(DateComparisonUtils.isSameDayUsingJoda(day1Morning, day1Evening));
+        assertTrue(DateComparisonUtils.isSameDayUsingDate4j(day1Morning, day1Evening));
+    }
+
+    @Test
+    public void givenDates_whenIsDifferentDay_thenReturnsFalse() {
+        assertFalse(DateComparisonUtils.isSameDayUsingLocalDate(day1Morning, day2Morning));
+        assertFalse(DateComparisonUtils.isSameDayUsingLocalDate(day1Evening, day2Morning));
+
+        assertFalse(DateComparisonUtils.isSameDayUsingInstant(day1Morning, day2Morning));
+        assertFalse(DateComparisonUtils.isSameDayUsingInstant(day1Evening, day2Morning));
+
+        assertFalse(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Morning, day2Morning));
+        assertFalse(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Evening, day2Morning));
+
+        assertFalse(DateComparisonUtils.isSameDayUsingCalendar(day1Morning, day2Morning));
+        assertFalse(DateComparisonUtils.isSameDayUsingCalendar(day1Evening, day2Morning));
+
+        assertFalse(DateComparisonUtils.isSameDayUsingApacheCommons(day1Morning, day2Morning));
+        assertFalse(DateComparisonUtils.isSameDayUsingApacheCommons(day1Evening, day2Morning));
+
+        assertFalse(DateComparisonUtils.isSameDayUsingJoda(day1Morning, day2Morning));
+        assertFalse(DateComparisonUtils.isSameDayUsingJoda(day1Evening, day2Morning));
+
+        assertFalse(DateComparisonUtils.isSameDayUsingDate4j(day1Morning, day2Morning));
+        assertFalse(DateComparisonUtils.isSameDayUsingDate4j(day1Evening, day2Morning));
+    }
+}

core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/datetime/DateUtilsUnitTest.java

@@ -9,12 +9,6 @@ import static org.junit.Assert.assertEquals;
 
 public class DateUtilsUnitTest {
 
-    @Test
-    public void givenTimeMillis_thenDateIsReturned() {
-        Date now = DateUtils.getNow();
-        assertEquals(DateUtils.getDate(now.getTime()), now);
-    }
-
     @Test
     public void givenDateAndPattern_thenDateIsCorrectlyReturned() throws ParseException {
         long milliseconds = new Date(2020 - 1900, 0, 1).getTime();

core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/datetime/sql/DateUtilsUnitTest.java

@@ -9,11 +9,6 @@ import org.junit.Test;
 
 public class DateUtilsUnitTest {
 
-    @Test
-    public void givenCurrentDate_thenTodayIsReturned() {
-        assertEquals(DateUtils.getNow().toLocalDate(), LocalDate.now());
-    }
-
     @Test(expected = IllegalArgumentException.class)
     public void givenDateAsString_whenPatternIsNotRespected_thenExceptionIsThrown() {
         DateUtils.getDate("2020 01 01");

core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/datetime/sql/TimestampUtilsUnitTest.java

@@ -1,22 +1,13 @@
 package com.baeldung.datetime.sql;
 
-import static org.junit.Assert.assertEquals;
-
 import org.junit.Test;
 
-import com.baeldung.datetime.sql.TimestampUtils;
-
 import java.text.ParseException;
-import java.util.Date;
+
+import static org.junit.Assert.assertEquals;
 
 public class TimestampUtilsUnitTest {
 
-    @Test
-    public void givenCurrentTimestamp_thenNowIsReturned() {
-        assertEquals(TimestampUtils.getNow()
-            .getTime(), new Date().getTime());
-    }
-
     @Test(expected = IllegalArgumentException.class)
     public void givenTimestampAsString_whenPatternIsNotRespected_thenExceptionIsThrown() {
         TimestampUtils.getTimestamp("2020/01/01 10:11-12");

core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/timer/DatabaseMigrationTaskUnitTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.timer;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class DatabaseMigrationTaskUnitTest {
+    @Test
+    void givenDatabaseMigrationTask_whenTimerScheduledForNowPlusTwoSeconds_thenDataMigratedAfterTwoSeconds() throws Exception {
+        List<String> oldDatabase = Arrays.asList("Harrison Ford", "Carrie Fisher", "Mark Hamill");
+        List<String> newDatabase = new ArrayList<>();
+
+        LocalDateTime twoSecondsLater = LocalDateTime.now().plusSeconds(2);
+        Date twoSecondsLaterAsDate = Date.from(twoSecondsLater.atZone(ZoneId.systemDefault()).toInstant());
+
+        new Timer().schedule(new DatabaseMigrationTask(oldDatabase, newDatabase), twoSecondsLaterAsDate);
+
+        while (LocalDateTime.now().isBefore(twoSecondsLater)) {
+            assertThat(newDatabase).isEmpty();
+            Thread.sleep(500);
+        }
+        assertThat(newDatabase).containsExactlyElementsOf(oldDatabase);
+    }
+
+    @Test
+    void givenDatabaseMigrationTask_whenTimerScheduledInTwoSeconds_thenDataMigratedAfterTwoSeconds() throws Exception {
+        List<String> oldDatabase = Arrays.asList("Harrison Ford", "Carrie Fisher", "Mark Hamill");
+        List<String> newDatabase = new ArrayList<>();
+
+        new Timer().schedule(new DatabaseMigrationTask(oldDatabase, newDatabase), 2000);
+
+        LocalDateTime twoSecondsLater = LocalDateTime.now().plusSeconds(2);
+
+        while (LocalDateTime.now().isBefore(twoSecondsLater)) {
+            assertThat(newDatabase).isEmpty();
+            Thread.sleep(500);
+        }
+        assertThat(newDatabase).containsExactlyElementsOf(oldDatabase);
+    }
+}

core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/timer/NewsletterTaskUnitTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.timer;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.Timer;
+
+class NewsletterTaskUnitTest {
+    private final Timer timer = new Timer();
+
+    @AfterEach
+    void afterEach() {
+        timer.cancel();
+    }
+
+    @Test
+    void givenNewsletterTask_whenTimerScheduledEachSecondFixedDelay_thenNewsletterSentEachSecond() throws Exception {
+        timer.schedule(new NewsletterTask(), 0, 1000);
+
+        for (int i = 0; i < 3; i++) {
+            Thread.sleep(1000);
+        }
+    }
+
+    @Test
+    void givenNewsletterTask_whenTimerScheduledEachSecondFixedRate_thenNewsletterSentEachSecond() throws Exception {
+        timer.scheduleAtFixedRate(new NewsletterTask(), 0, 1000);
+
+        for (int i = 0; i < 3; i++) {
+            Thread.sleep(1000);
+        }
+    }
+}

core-java-modules/core-java-datetime-java8/src/main/java/com/baeldung/datebasics/CreateDate.java

@@ -0,0 +1,45 @@
+package com.baeldung.datebasics;
+
+import java.time.Clock;
+import java.time.LocalDate;
+import java.time.Month;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+
+public class CreateDate {
+	public LocalDate getTodaysDate() {
+		return LocalDate.now();
+	}
+
+	public LocalDate getTodaysDateFromClock() {
+		return LocalDate.now(Clock.systemDefaultZone());
+	}
+
+	public LocalDate getTodaysDateFromZone(String zone) {
+		return LocalDate.now(ZoneId.of(zone));
+	}
+
+	public LocalDate getCustomDateOne(int year, int month, int dayOfMonth) {
+		return LocalDate.of(year, month, dayOfMonth);
+	}
+
+	public LocalDate getCustomDateTwo(int year, Month month, int dayOfMonth) {
+		return LocalDate.of(year, month, dayOfMonth);
+	}
+
+	public LocalDate getDateFromEpochDay(long epochDay) {
+		return LocalDate.ofEpochDay(epochDay);
+	}
+
+	public LocalDate getDateFromYearAndDayOfYear(int year, int dayOfYear) {
+		return LocalDate.ofYearDay(year, dayOfYear);
+	}
+
+	public LocalDate getDateFromString(String date) {
+		return LocalDate.parse(date);
+	}
+
+	public LocalDate getDateFromStringAndFormatter(String date, String pattern) {
+		return LocalDate.parse(date, DateTimeFormatter.ofPattern(pattern));
+	}
+}

core-java-modules/core-java-datetime-java8/src/test/java/com/baeldung/datebasics/CreateDateUnitTest.java

@@ -0,0 +1,56 @@
+package com.baeldung.datebasics;
+
+import static org.junit.Assert.assertEquals;
+
+import java.time.Month;
+
+import org.junit.Test;
+
+public class CreateDateUnitTest {
+    private CreateDate date = new CreateDate();
+    
+    @Test
+    public void whenUsingNowMethod_thenLocalDate() {
+        assertEquals("2020-01-08", date.getTodaysDate());
+    }
+    
+    @Test
+    public void whenUsingClock_thenLocalDate() {
+        assertEquals("2020-01-08", date.getTodaysDateFromClock());
+    }
+    
+    @Test
+    public void givenValues_whenUsingZone_thenLocalDate() {
+        assertEquals("2020-01-08", date.getTodaysDateFromZone("Asia/Kolkata"));
+    }
+    
+    @Test
+    public void givenValues_whenUsingOfMethod_thenLocalDate() {
+        assertEquals("2020-01-08", date.getCustomDateOne(2020, 1, 8));
+    }
+    
+    @Test
+    public void givenValuesWithMonthEnum_whenUsingOfMethod_thenLocalDate() {
+        assertEquals("2020-01-08", date.getCustomDateTwo(2020, Month.JANUARY, 8));
+    }
+    
+    @Test
+    public void givenValues_whenUsingEpochDay_thenLocalDate() {
+        assertEquals("2020-01-08", date.getDateFromEpochDay(18269));
+    }
+    
+    @Test
+    public void givenValues_whenUsingYearDay_thenLocalDate() {
+        assertEquals("2020-01-08", date.getDateFromYearAndDayOfYear(2020, 8));
+    }
+    
+    @Test
+    public void givenValues_whenUsingParse_thenLocalDate() {
+        assertEquals("2020-01-08", date.getDateFromString("2020-01-08"));
+    }
+    
+    @Test
+    public void givenValuesWithFormatter_whenUsingParse_thenLocalDate() {
+        assertEquals("2020-01-08", date.getDateFromStringAndFormatter("8-Jan-2020", "d-MMM-yyyy"));
+    }
+}

core-java-modules/core-java-lang-2/src/main/java/com/baeldung/finallykeyword/FinallyExample.java

@@ -0,0 +1,14 @@
+package com.baeldung.finallykeyword;
+
+public class FinallyExample {
+
+    public void printCount(String count) {
+        try {
+            System.out.println("The count is " + Integer.parseInt(count));
+        } catch (NumberFormatException e) {
+            System.out.println("No count");
+        } finally {
+            System.out.println("In finally");
+        }
+    }
+}