Merge https://github.com/eugenp/tutorials

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>

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

@@ -0,0 +1,5 @@
+## Core Java Arrays (Part 3)
+
+This module contains articles about Java arrays
+
+## Relevant Articles

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

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<artifactId>core-java-arrays-3</artifactId>
+	<version>0.1.0-SNAPSHOT</version>
+	<name>core-java-arrays-3</name>
+	<packaging>jar</packaging>
+
+	<parent>
+		<groupId>com.baeldung</groupId>
+		<artifactId>parent-java</artifactId>
+		<version>0.0.1-SNAPSHOT</version>
+		<relativePath>../../parent-java</relativePath>
+	</parent>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.assertj</groupId>
+			<artifactId>assertj-core</artifactId>
+			<version>${assertj.version}</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<properties>
+		<assertj.version>3.14.0</assertj.version>
+	</properties>
+
+</project>

core-java-modules/core-java-arrays-3/src/test/java/com/baeldung/arrays/deepequals/ArraysDeepEqualsUnitTest.java

@@ -0,0 +1,96 @@
+package com.baeldung.arrays.deepequals;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Arrays;
+import java.util.Objects;
+import org.junit.jupiter.api.Test;
+
+public class ArraysDeepEqualsUnitTest {
+
+    class Person {
+        private int id;
+        private String name;
+        private int age;
+
+        Person(int id, String name, int age) {
+            this.id = id;
+            this.name = name;
+            this.age = age;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) {
+                return true;
+            }
+            if (obj == null) {
+                return false;
+            }
+            if (!(obj instanceof Person))
+                return false;
+            Person person = (Person) obj;
+            return id == person.id && name.equals(person.name) && age == person.age;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(id, name, age);
+        }
+    }
+
+    @Test
+    void givenTwoUnidimensionalObjectTypeArrays_whenUsingEqualsAndDeepEquals_thenBothShouldReturnTrue() {
+        Object[] anArray = new Object[] { "string1", "string2", "string3" };
+        Object[] anotherArray = new Object[] { "string1", "string2", "string3" };
+
+        assertTrue(Arrays.equals(anArray, anotherArray));
+        assertTrue(Arrays.deepEquals(anArray, anotherArray));
+    }
+
+    @Test
+    void givenTwoUnidimensionalObjectTypeArraysWithNullElements_whenUsingEqualsAndDeepEquals_thenBothShouldReturnTrue() {
+        Object[] anArray = new Object[] { "string1", null, "string3" };
+        Object[] anotherArray = new Object[] { "string1", null, "string3" };
+
+        assertTrue(Arrays.equals(anArray, anotherArray));
+        assertTrue(Arrays.deepEquals(anArray, anotherArray));
+    }
+
+    @Test
+    void givenTwoUnidimensionalObjectTypeArraysWithNestedElements_whenUsingEqualsAndDeepEquals_thenShouldReturnDifferently() {
+        Object[] anArray = new Object[] { "string1", null, new String[] { "nestedString1", "nestedString2" } };
+        Object[] anotherArray = new Object[] { "string1", null, new String[] { "nestedString1", "nestedString2" } };
+
+        assertFalse(Arrays.equals(anArray, anotherArray));
+        assertTrue(Arrays.deepEquals(anArray, anotherArray));
+    }
+
+    @Test
+    void givenTwoMultidimensionalPrimitiveTypeArrays_whenUsingEqualsAndDeepEquals_thenBothShouldReturnDifferently() {
+        int[][] anArray = { { 1, 2, 3 }, { 4, 5, 6, 9 }, { 7 } };
+        int[][] anotherArray = { { 1, 2, 3 }, { 4, 5, 6, 9 }, { 7 } };
+
+        assertFalse(Arrays.equals(anArray, anotherArray));
+        assertTrue(Arrays.deepEquals(anArray, anotherArray));
+    }
+
+    @Test
+    void givenTwoMultidimensionalObjectTypeArrays_whenUsingEqualsAndDeepEquals_thenBothShouldReturnDifferently() {
+        Person personArray1[][] = { { new Person(1, "John", 22), new Person(2, "Mike", 23) }, { new Person(3, "Steve", 27), new Person(4, "Gary", 28) } };
+        Person personArray2[][] = { { new Person(1, "John", 22), new Person(2, "Mike", 23) }, { new Person(3, "Steve", 27), new Person(4, "Gary", 28) } };
+
+        assertFalse(Arrays.equals(personArray1, personArray2));
+        assertTrue(Arrays.deepEquals(personArray1, personArray2));
+    }
+
+    @Test
+    void givenTwoMultidimensionalObjectTypeArrays_whenUsingDeepEqualsFromObjectsAndArraysClasses_thenBothShouldReturnTrue() {
+        Person personArray1[][] = { { new Person(1, "John", 22), new Person(2, "Mike", 23) }, { new Person(3, "Steve", 27), new Person(4, "Gary", 28) } };
+        Person personArray2[][] = { { new Person(1, "John", 22), new Person(2, "Mike", 23) }, { new Person(3, "Steve", 27), new Person(4, "Gary", 28) } };
+
+        assertTrue(Objects.deepEquals(personArray1, personArray2));
+        assertTrue(Arrays.deepEquals(personArray1, personArray2));
+    }
+}

core-java-modules/core-java-arrays/src/main/java/com/baeldung/array/Find2ndLargestInArray.java

@@ -1,20 +0,0 @@
-package com.baeldung.array;
-
-public class Find2ndLargestInArray {
-
-    public static int find2ndLargestElement(int[] array) {
-        int maxElement = array[0];
-        int secondLargestElement = -1;
-
-        for (int index = 0; index < array.length; index++) {
-            if (maxElement <= array[index]) {
-                secondLargestElement = maxElement;
-                maxElement = array[index];
-            } else if (secondLargestElement < array[index]) {
-                secondLargestElement = array[index];
-            }
-        }
-        return secondLargestElement;
-    }
-
-}

core-java-modules/core-java-arrays/src/main/java/com/baeldung/array/FindElementInArray.java

@@ -1,22 +0,0 @@
-package com.baeldung.array;
-
-import java.util.Arrays;
-
-public class FindElementInArray {
-
-    public static boolean findGivenElementInArrayWithoutUsingStream(int[] array, int element) {
-        boolean actualResult = false;
-
-        for (int index = 0; index < array.length; index++) {
-            if (element == array[index]) {
-                actualResult = true;
-                break;
-            }
-        }
-        return actualResult;
-    }
-
-    public static boolean findGivenElementInArrayUsingStream(int[] array, int element) {
-        return Arrays.stream(array).filter(x -> element == x).findFirst().isPresent();
-    }
-}

core-java-modules/core-java-arrays/src/test/java/com/baeldung/array/Find2ndLargestInArrayUnitTest.java

@@ -1,16 +0,0 @@
-package com.baeldung.array;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-public class Find2ndLargestInArrayUnitTest {
-    @Test
-    public void givenAnIntArray_thenFind2ndLargestElement() {
-        int[] array = { 1, 3, 24, 16, 87, 20 };
-        int expected2ndLargest = 24;
-
-        int actualSecondLargestElement = Find2ndLargestInArray.find2ndLargestElement(array);
-
-        Assert.assertEquals(expected2ndLargest, actualSecondLargestElement);
-    }
-}

core-java-modules/core-java-arrays/src/test/java/com/baeldung/array/FindElementInArrayUnitTest.java

@@ -1,35 +0,0 @@
-package com.baeldung.array;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-public class FindElementInArrayUnitTest {
-    @Test
-    public void givenAnIntArray_whenNotUsingStream_thenFindAnElement() {
-        int[] array = { 1, 3, 4, 8, 19, 20 };
-        int element = 19;
-        boolean expectedResult = true;
-        boolean actualResult = FindElementInArray.findGivenElementInArrayWithoutUsingStream(array, element);
-        Assert.assertEquals(expectedResult, actualResult);
-
-        element = 78;
-        expectedResult = false;
-        actualResult = FindElementInArray.findGivenElementInArrayWithoutUsingStream(array, element);
-        Assert.assertEquals(expectedResult, actualResult);
-    }
-
-    @Test
-    public void givenAnIntArray_whenUsingStream_thenFindAnElement() {
-        int[] array = { 15, 16, 12, 18 };
-        int element = 16;
-        boolean expectedResult = true;
-        boolean actualResult = FindElementInArray.findGivenElementInArrayUsingStream(array, element);
-        Assert.assertEquals(expectedResult, actualResult);
-
-        element = 20;
-        expectedResult = false;
-        actualResult = FindElementInArray.findGivenElementInArrayUsingStream(array, element);
-        Assert.assertEquals(expectedResult, actualResult);
-    }
-
-}

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

@@ -11,5 +11,5 @@ This module contains articles about core Java input and output (IO)
 - [List Files in a Directory in Java](https://www.baeldung.com/java-list-directory-files)
 - [Java – Append Data to a File](https://www.baeldung.com/java-append-to-file)
 - [How to Copy a File with Java](https://www.baeldung.com/java-copy-file)
-- [Create a Directory in Java](https://www.baeldung.com/java-create-directory)
+- [Create a Directory in Java](https://www.baeldung.com/java-create-directory) 
 - [[<-- Prev]](/core-java-modules/core-java-io)

core-java-modules/core-java-io/src/test/java/com/baeldung/readfile/FileOperationsManualTest.java

@@ -1,134 +0,0 @@
-package com.baeldung.readfile;
-
-import org.apache.commons.io.FileUtils;
-import org.apache.commons.io.IOUtils;
-import org.hamcrest.CoreMatchers;
-import org.hamcrest.Matchers;
-import org.junit.Test;
-
-import java.io.BufferedReader;
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.net.URISyntaxException;
-import java.net.URL;
-import java.net.URLConnection;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
-
-public class FileOperationsManualTest {
-
-    @Test
-    public void givenFileName_whenUsingClassloader_thenFileData() throws IOException {
-        String expectedData = "Hello World from fileTest.txt!!!";
-
-        ClassLoader classLoader = getClass().getClassLoader();
-        File file = new File(classLoader.getResource("fileTest.txt").getFile());
-        InputStream inputStream = new FileInputStream(file);
-        String data = readFromInputStream(inputStream);
-
-        assertEquals(expectedData, data.trim());
-    }
-
-    @Test
-    public void givenFileNameAsAbsolutePath_whenUsingClasspath_thenFileData() throws IOException {
-        String expectedData = "Hello World from fileTest.txt!!!";
-
-        Class clazz = FileOperationsManualTest.class;
-        InputStream inputStream = clazz.getResourceAsStream("/fileTest.txt");
-        String data = readFromInputStream(inputStream);
-
-        assertEquals(expectedData, data.trim());
-    }
-
-    @Test
-    public void givenFileName_whenUsingJarFile_thenFileData() throws IOException {
-        String expectedData = "MIT License";
-
-        Class clazz = Matchers.class;
-        InputStream inputStream = clazz.getResourceAsStream("/LICENSE.txt");
-        String data = readFromInputStream(inputStream);
-
-        assertThat(data.trim(), CoreMatchers.containsString(expectedData));
-    }
-
-    @Test
-    public void givenURLName_whenUsingURL_thenFileData() throws IOException {
-        String expectedData = "Example Domain";
-
-        URL urlObject = new URL("http://www.example.com/");
-
-        URLConnection urlConnection = urlObject.openConnection();
-
-        InputStream inputStream = urlConnection.getInputStream();
-        String data = readFromInputStream(inputStream);
-
-        assertThat(data.trim(), CoreMatchers.containsString(expectedData));
-    }
-
-    @Test
-    public void givenFileName_whenUsingFileUtils_thenFileData() throws IOException {
-        String expectedData = "Hello World from fileTest.txt!!!";
-
-        ClassLoader classLoader = getClass().getClassLoader();
-        File file = new File(classLoader.getResource("fileTest.txt").getFile());
-        String data = FileUtils.readFileToString(file, "UTF-8");
-
-        assertEquals(expectedData, data.trim());
-    }
-
-    @Test
-    public void givenFilePath_whenUsingFilesReadAllBytes_thenFileData() throws IOException, URISyntaxException {
-        String expectedData = "Hello World from fileTest.txt!!!";
-
-        Path path = Paths.get(getClass().getClassLoader().getResource("fileTest.txt").toURI());
-
-        byte[] fileBytes = Files.readAllBytes(path);
-        String data = new String(fileBytes);
-
-        assertEquals(expectedData, data.trim());
-    }
-
-    @Test
-    public void givenFilePath_whenUsingFilesLines_thenFileData() throws IOException, URISyntaxException {
-        String expectedData = "Hello World from fileTest.txt!!!";
-
-        Path path = Paths.get(getClass().getClassLoader().getResource("fileTest.txt").toURI());
-
-        Stream<String> lines = Files.lines(path);
-        String data = lines.collect(Collectors.joining("\n"));
-        lines.close();
-
-        assertEquals(expectedData, data.trim());
-    }
-
-    private String readFromInputStream(InputStream inputStream) throws IOException {
-        StringBuilder resultStringBuilder = new StringBuilder();
-        try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream))) {
-            String line;
-            while ((line = bufferedReader.readLine()) != null) {
-                resultStringBuilder.append(line).append("\n");
-            }
-        }
-
-        return resultStringBuilder.toString();
-    }
-    
-    @Test
-    public void givenFileName_whenUsingIOUtils_thenFileData() throws IOException {
-        String expectedData = "This is a content of the file";
-
-        FileInputStream fis = new FileInputStream("src/test/resources/fileToRead.txt");
-        String data = IOUtils.toString(fis, "UTF-8");
-        
-        assertEquals(expectedData, data.trim());
-    }
-}

core-java-modules/core-java-io/src/test/java/com/baeldung/readfile/JavaReadFromFileUnitTest.java

@@ -1,11 +1,15 @@
 package com.baeldung.readfile;
 
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.IOUtils;
+import org.hamcrest.CoreMatchers;
+import org.hamcrest.Matchers;
 import org.junit.Test;
-import org.junit.Ignore;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.*;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.net.URLConnection;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.nio.charset.Charset;
@@ -13,55 +17,148 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.Scanner;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
 public class JavaReadFromFileUnitTest {
 
-    private static final Logger LOG = LoggerFactory.getLogger(JavaReadFromFileUnitTest.class);
-
     @Test
     public void whenReadWithBufferedReader_thenCorrect() throws IOException {
-        final String expected_value = "Hello world";
+        final String expected_value = "Hello, world!";
 
-        final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/test_read.in"));
+        final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/fileTest.txt"));
         final String currentLine = reader.readLine();
         reader.close();
 
         assertEquals(expected_value, currentLine);
     }
 
+    @Test
+    public void givenFileName_whenUsingClassloader_thenFileData() throws IOException {
+        String expectedData = "Hello, world!";
+
+        ClassLoader classLoader = getClass().getClassLoader();
+        File file = new File(classLoader.getResource("fileTest.txt").getFile());
+        InputStream inputStream = new FileInputStream(file);
+        String data = readFromInputStream(inputStream);
+
+        assertEquals(expectedData, data.trim());
+    }
+
+    @Test
+    public void givenFileNameAsAbsolutePath_whenUsingClasspath_thenFileData() throws IOException {
+        String expectedData = "Hello, world!";
+
+        Class clazz = JavaReadFromFileUnitTest.class;
+        InputStream inputStream = clazz.getResourceAsStream("/fileTest.txt");
+        String data = readFromInputStream(inputStream);
+
+        assertEquals(expectedData, data.trim());
+    }
+
+    @Test
+    public void givenFileName_whenUsingJarFile_thenFileData() throws IOException {
+        String expectedData = "BSD License";
+
+        Class clazz = Matchers.class;
+        InputStream inputStream = clazz.getResourceAsStream("/LICENSE.txt");
+        String data = readFromInputStream(inputStream);
+
+        assertThat(data.trim(), CoreMatchers.containsString(expectedData));
+    }
+
+    @Test
+    public void givenURLName_whenUsingURL_thenFileData() throws IOException {
+        String expectedData = "Example Domain";
+
+        URL urlObject = new URL("http://www.example.com/");
+
+        URLConnection urlConnection = urlObject.openConnection();
+
+        InputStream inputStream = urlConnection.getInputStream();
+        String data = readFromInputStream(inputStream);
+
+        assertThat(data.trim(), CoreMatchers.containsString(expectedData));
+    }
+
+    @Test
+    public void givenFileName_whenUsingFileUtils_thenFileData() throws IOException {
+        String expectedData = "Hello, world!";
+
+        ClassLoader classLoader = getClass().getClassLoader();
+        File file = new File(classLoader.getResource("fileTest.txt").getFile());
+        String data = FileUtils.readFileToString(file, "UTF-8");
+
+        assertEquals(expectedData, data.trim());
+    }
+
+    @Test
+    public void givenFilePath_whenUsingFilesReadAllBytes_thenFileData() throws IOException, URISyntaxException {
+        String expectedData = "Hello, world!";
+
+        Path path = Paths.get(getClass().getClassLoader().getResource("fileTest.txt").toURI());
+
+        byte[] fileBytes = Files.readAllBytes(path);
+        String data = new String(fileBytes);
+
+        assertEquals(expectedData, data.trim());
+    }
+
+    @Test
+    public void givenFilePath_whenUsingFilesLines_thenFileData() throws IOException, URISyntaxException {
+        String expectedData = "Hello, world!";
+
+        Path path = Paths.get(getClass().getClassLoader().getResource("fileTest.txt").toURI());
+
+        Stream<String> lines = Files.lines(path);
+        String data = lines.collect(Collectors.joining("\n"));
+        lines.close();
+
+        assertEquals(expectedData, data.trim());
+    }
+
+    @Test
+    public void givenFileName_whenUsingIOUtils_thenFileData() throws IOException {
+        String expectedData = "Hello, world!";
+
+        FileInputStream fis = new FileInputStream("src/test/resources/fileTest.txt");
+        String data = IOUtils.toString(fis, "UTF-8");
+
+        assertEquals(expectedData, data.trim());
+    }
+
     @Test
     public void whenReadWithScanner_thenCorrect() throws IOException {
-        final Scanner scanner = new Scanner(new File("src/test/resources/test_read1.in"));
+        final Scanner scanner = new Scanner(new File("src/test/resources/fileTest.txt"));
         scanner.useDelimiter(" ");
 
         assertTrue(scanner.hasNext());
-        assertEquals("Hello", scanner.next());
-        assertEquals("world", scanner.next());
-        assertEquals(1, scanner.nextInt());
+        assertEquals("Hello,", scanner.next());
+        assertEquals("world!", scanner.next());
 
         scanner.close();
-
     }
 
     @Test
     public void whenReadWithScannerTwoDelimiters_thenCorrect() throws IOException {
-        final Scanner scanner = new Scanner(new File("src/test/resources/test_read2.in"));
-        scanner.useDelimiter(",| ");
+        final Scanner scanner = new Scanner(new File("src/test/resources/fileTest.txt"));
+        scanner.useDelimiter("\\s|,");
 
-        assertTrue(scanner.hasNextInt());
-        assertEquals(2, scanner.nextInt());
-        assertEquals(3, scanner.nextInt());
-        assertEquals(4, scanner.nextInt());
+        assertTrue(scanner.hasNext());
+        assertEquals("Hello", scanner.next());
+        assertEquals("", scanner.next());
+        assertEquals("world!", scanner.next());
 
         scanner.close();
     }
 
     @Test
     public void whenReadWithStreamTokenizer_thenCorrectTokens() throws IOException {
-        final FileReader reader = new FileReader("src/test/resources/test_read3.in");
+        final FileReader reader = new FileReader("src/test/resources/fileTestTokenizer.txt");
         final StreamTokenizer tokenizer = new StreamTokenizer(reader);
 
         tokenizer.nextToken();
@@ -78,49 +175,36 @@ public class JavaReadFromFileUnitTest {
 
     @Test
     public void whenReadWithDataInputStream_thenCorrect() throws IOException {
-        final String expected_value = "Hello";
+        String expectedValue = "Hello, world!";
+        String file ="src/test/resources/fileTest.txt";
 
-        String result;
-        final DataInputStream reader = new DataInputStream(new FileInputStream("src/test/resources/test_read4.in"));
-        result = reader.readUTF();
-        reader.close();
+        String result = null;
 
-        assertEquals(expected_value, result);
-    }
+        DataInputStream reader = new DataInputStream(new FileInputStream(file));
+        int nBytesToRead = reader.available();
+        if(nBytesToRead > 0) {
+            byte[] bytes = new byte[nBytesToRead];
+            reader.read(bytes);
+            result = new String(bytes);
+        }
 
-    public void whenReadTwoFilesWithSequenceInputStream_thenCorrect() throws IOException {
-        final int expected_value1 = 2000;
-        final int expected_value2 = 5000;
-
-        final FileInputStream stream1 = new FileInputStream("src/test/resources/test_read5.in");
-        final FileInputStream stream2 = new FileInputStream("src/test/resources/test_read6.in");
-
-        final SequenceInputStream sequence = new SequenceInputStream(stream1, stream2);
-        final DataInputStream reader = new DataInputStream(sequence);
-
-        assertEquals(expected_value1, reader.readInt());
-        assertEquals(expected_value2, reader.readInt());
-
-        reader.close();
-        stream2.close();
+        assertEquals(expectedValue, result);
     }
 
     @Test
-    @Ignore // TODO
     public void whenReadUTFEncodedFile_thenCorrect() throws IOException {
         final String expected_value = "青空";
-        final BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("src/test/resources/test_read7.in"), "UTF-8"));
+        final BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("src/test/resources/fileTestUtf8.txt"), "UTF-8"));
         final String currentLine = reader.readLine();
         reader.close();
-        LOG.debug(currentLine);
-        
+
         assertEquals(expected_value, currentLine);
     }
 
     @Test
     public void whenReadFileContentsIntoString_thenCorrect() throws IOException {
-        final String expected_value = "Hello world \n Test line \n";
-        final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/test_read8.in"));
+        final String expected_value = "Hello, world!\n";
+        final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/fileTest.txt"));
         final StringBuilder builder = new StringBuilder();
         String currentLine = reader.readLine();
         while (currentLine != null) {
@@ -136,8 +220,8 @@ public class JavaReadFromFileUnitTest {
 
     @Test
     public void whenReadWithFileChannel_thenCorrect() throws IOException {
-        final String expected_value = "Hello world";
-        final RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r");
+        final String expected_value = "Hello, world!";
+        final RandomAccessFile reader = new RandomAccessFile("src/test/resources/fileTest.txt", "r");
         final FileChannel channel = reader.getChannel();
 
         int bufferSize = 1024;
@@ -154,8 +238,8 @@ public class JavaReadFromFileUnitTest {
 
     @Test
     public void whenReadSmallFileJava7_thenCorrect() throws IOException {
-        final String expected_value = "Hello world";
-        final Path path = Paths.get("src/test/resources/test_read.in");
+        final String expected_value = "Hello, world!";
+        final Path path = Paths.get("src/test/resources/fileTest.txt");
 
         final String read = Files.readAllLines(path, Charset.defaultCharset()).get(0);
         assertEquals(expected_value, read);
@@ -163,12 +247,24 @@ public class JavaReadFromFileUnitTest {
 
     @Test
     public void whenReadLargeFileJava7_thenCorrect() throws IOException {
-        final String expected_value = "Hello world";
+        final String expected_value = "Hello, world!";
 
-        final Path path = Paths.get("src/test/resources/test_read.in");
+        final Path path = Paths.get("src/test/resources/fileTest.txt");
         final BufferedReader reader = Files.newBufferedReader(path, Charset.defaultCharset());
         final String line = reader.readLine();
         assertEquals(expected_value, line);
     }
 
+    private String readFromInputStream(InputStream inputStream) throws IOException {
+        StringBuilder resultStringBuilder = new StringBuilder();
+        try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream))) {
+            String line;
+            while ((line = bufferedReader.readLine()) != null) {
+                resultStringBuilder.append(line).append("\n");
+            }
+        }
+
+        return resultStringBuilder.toString();
+    }
+
 }

core-java-modules/core-java-io/src/test/resources/fileTest.txt

@@ -1 +1 @@
-Hello World from fileTest.txt!!!
+Hello, world!

core-java-modules/core-java-io/src/test/resources/test_read1.in

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

core-java-modules/core-java-io/src/test/resources/test_read2.in

@@ -1 +0,0 @@
-2,3 4

core-java-modules/core-java-io/src/test/resources/test_read8.in

@@ -1,2 +0,0 @@
-Hello world 
- Test line 

core-java-modules/core-java-nio-2/src/main/java/com/baeldung/lock/FileLocks.java

@@ -0,0 +1,148 @@
+package com.baeldung.lock;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
+import java.nio.channels.NonReadableChannelException;
+import java.nio.channels.NonWritableChannelException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+
+public class FileLocks {
+
+    private static final Logger LOG = LoggerFactory.getLogger(FileLocks.class);
+
+    // Write locks
+
+    /**
+     * Trying to get an exclusive lock on a read-only FileChannel won't work.
+     */
+    static void getExclusiveLockFromInputStream() throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (FileInputStream fis = new FileInputStream(path.toFile());
+            FileLock lock = fis.getChannel()
+                .lock()) {
+            LOG.debug("This won't happen");
+        } catch (NonWritableChannelException e) {
+            LOG.error("The channel obtained through a FileInputStream isn't writable. You can't obtain an exclusive lock on it!");
+            throw e;
+        }
+    }
+
+    /**
+     * Gets an exclusive lock from a RandomAccessFile. Works because the file is writable.
+     * @param from beginning of the locked region
+     * @param size how many bytes to lock
+     * @return A lock object representing the newly-acquired lock
+     * @throws IOException if there is a problem creating the temporary file
+     */
+    static FileLock getExclusiveLockFromRandomAccessFile(long from, long size) throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (RandomAccessFile file = new RandomAccessFile(path.toFile(), "rw");
+            FileLock lock = file.getChannel()
+                .lock(from, size, false)) {
+            if (lock.isValid()) {
+                LOG.debug("This is a valid exclusive lock");
+                return lock;
+            }
+            return null;
+        } catch (Exception e) {
+            LOG.error(e.getMessage());
+        }
+        return null;
+    }
+
+    /**
+     * Acquires an exclusive lock on a file region.
+     * @param from beginning of the locked region
+     * @param size how many bytes to lock
+     * @return A lock object representing the newly-acquired lock
+     * @throws IOException if there is a problem creating the temporary file
+     */
+    static FileLock getExclusiveLockFromFileChannelOpen(long from, long size) throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (FileChannel channel = FileChannel.open(path, StandardOpenOption.APPEND); FileLock lock = channel.lock(from, size, false)) {
+            String text = "Hello, world.";
+            ByteBuffer buffer = ByteBuffer.allocate(text.length() + System.lineSeparator()
+                .length());
+            buffer.put((text + System.lineSeparator()).getBytes(StandardCharsets.UTF_8));
+            buffer.flip();
+            while (buffer.hasRemaining()) {
+                channel.write(buffer, channel.size());
+            }
+            LOG.debug("This was written to the file");
+            Files.lines(path)
+                .forEach(LOG::debug);
+            return lock;
+        }
+    }
+
+    // Read locks
+
+    /**
+     * Trying to get a shared lock on a write-only FileChannel won't work.
+     */
+    static void getReadLockFromOutputStream() throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (FileOutputStream fis = new FileOutputStream(path.toFile());
+            FileLock lock = fis.getChannel()
+                .lock(0, Long.MAX_VALUE, true)) {
+            LOG.debug("This won't happen");
+        } catch (NonReadableChannelException e) {
+            LOG.error("The channel obtained through a FileOutputStream isn't readable. " + "You can't obtain an shared lock on it!");
+            throw e;
+        }
+    }
+
+    /**
+     * Gets a lock from an <tt>InputStream</tt>.
+     * @param from beginning of the locked region
+     * @param size how many bytes to lock
+     * @return A lock object representing the newly-acquired lock
+     * @throws IOException if there is a problem creating the temporary file
+     */
+    static FileLock getReadLockFromInputStream(long from, long size) throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (FileInputStream fis = new FileInputStream(path.toFile());
+            FileLock lock = fis.getChannel()
+                .lock(from, size, true)) {
+            if (lock.isValid()) {
+                LOG.debug("This is a valid shared lock");
+                return lock;
+            }
+            return null;
+        }
+    }
+
+    /**
+     * Gets an exclusive lock from a RandomAccessFile. Works because the file is readable.
+     * @param from beginning of the locked region
+     * @param size how many bytes to lock
+     * @return A lock object representing the newly-acquired lock
+     * @throws IOException if there is a problem creating the temporary file
+     */
+    static FileLock getReadLockFromRandomAccessFile(long from, long size) throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (RandomAccessFile file = new RandomAccessFile(path.toFile(), "r"); // could also be "rw", but "r" is sufficient for reading
+            FileLock lock = file.getChannel()
+                .lock(from, size, true)) {
+            if (lock.isValid()) {
+                LOG.debug("This is a valid shared lock");
+                return lock;
+            }
+        } catch (Exception e) {
+            LOG.error(e.getMessage());
+        }
+        return null;
+    }
+
+}

core-java-modules/core-java-nio-2/src/test/java/com/baeldung/lock/FileLocksUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.lock;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.IOException;
+import java.nio.channels.FileLock;
+import java.nio.channels.NonReadableChannelException;
+import java.nio.channels.NonWritableChannelException;
+
+import org.junit.jupiter.api.Test;
+
+class FileLocksUnitTest {
+
+    @Test
+    void givenAnInputStream_whenGetWriteLock_thenThrowNonWritableChannelException() {
+        assertThrows(NonWritableChannelException.class, () -> FileLocks.getExclusiveLockFromInputStream());
+    }
+
+    @Test
+    void givenARandomAccessFileWithReadWriteAccess_whenGetWriteLock_thenLock() throws IOException {
+        FileLock lock = FileLocks.getExclusiveLockFromRandomAccessFile(0, 10);
+        assertNotNull(lock);
+        assertFalse(lock.isShared());
+    }
+
+    @Test
+    void givenAPath_whenGetExclusiveLock_thenLock() throws IOException {
+        FileLock lock = FileLocks.getExclusiveLockFromFileChannelOpen(0, 10);
+        assertNotNull(lock);
+        assertFalse(lock.isShared());
+    }
+
+    @Test
+    void givenAFileOutputStream_whenGetSharedLock_thenThrowNonReadableChannelException() {
+        assertThrows(NonReadableChannelException.class, FileLocks::getReadLockFromOutputStream);
+    }
+
+    @Test
+    void givenAnInputStream_whenGetSharedLock_thenLock() throws IOException {
+        FileLock lock = FileLocks.getReadLockFromInputStream(0, 10);
+        assertNotNull(lock);
+        assertTrue(lock.isShared());
+    }
+
+    @Test
+    void givenARandomAccessFile_whenGetSharedLock_thenLock() throws IOException {
+        FileLock lock = FileLocks.getReadLockFromRandomAccessFile(0, 10);
+        assertNotNull(lock);
+        assertTrue(lock.isShared());
+    }
+}

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

@@ -11,7 +11,7 @@
 - [Introduction to Java Serialization](http://www.baeldung.com/java-serialization)
 - [Guide to UUID in Java](http://www.baeldung.com/java-uuid)
 - [Creating a Java Compiler Plugin](http://www.baeldung.com/java-build-compiler-plugin)
-- [Quick Guide to Java Stack](http://www.baeldung.com/java-stack)
+- [Quick Guide to the Java Stack](http://www.baeldung.com/java-stack)
 - [Compiling Java *.class Files with javac](http://www.baeldung.com/javac)
 - [Introduction to Javadoc](http://www.baeldung.com/javadoc)
 - [Guide to the Externalizable Interface in Java](http://www.baeldung.com/java-externalizable)

core-java-modules/core-java/src/test/java/com/baeldung/timer/JavaTimerLongRunningUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.timer;
 
 import org.junit.Test;
 import org.slf4j.Logger;

core-java-modules/pom.xml

@@ -31,6 +31,7 @@
         <module>core-java-annotations</module>
         <module>core-java-arrays</module>
         <module>core-java-arrays-2</module>
+        <module>core-java-arrays-3</module>
 
         <module>core-java-collections</module>
         <module>core-java-collections-2</module>

core-kotlin-modules/core-kotlin-2/README.md

@@ -5,4 +5,5 @@ This module contains articles about Kotlin core features.
 ### Relevant articles:
 - [Working with Dates in Kotlin](https://www.baeldung.com/kotlin-dates)
 - [Kotlin Ternary Conditional Operator](https://www.baeldung.com/kotlin-ternary-operator)
+- [Sequences in Kotlin](https://www.baeldung.com/kotlin/sequences)
 - [[<-- Prev]](/core-kotlin-modules/core-kotlin)

core-kotlin-modules/core-kotlin/README.md

@@ -13,4 +13,7 @@ This module contains articles about Kotlin core features.
 - [Implementing a Binary Tree in Kotlin](https://www.baeldung.com/kotlin-binary-tree)
 - [JUnit 5 for Kotlin Developers](https://www.baeldung.com/junit-5-kotlin)
 - [Converting Kotlin Data Class from JSON using GSON](https://www.baeldung.com/kotlin-json-convert-data-class)
+- [Fuel HTTP Library with Kotlin](https://www.baeldung.com/kotlin-fuel)
+- [Introduction to Kovenant Library for Kotlin](https://www.baeldung.com/kotlin-kovenant)
+- [Dependency Injection for Kotlin with Injekt](https://www.baeldung.com/kotlin-dependency-injection-with-injekt)
 - [[More --> ]](/core-kotlin-modules/core-kotlin-2)

core-scala/README.md

@@ -5,3 +5,4 @@ This module contains articles about Scala's core features
 ### Relevant Articles: 
 
 - [Introduction to Scala](https://www.baeldung.com/scala-intro)
+- [Regular Expressions in Scala](https://www.baeldung.com/scala/regular-expressions)

core-scala/src/test/scala/com/baeldung/scala/HigherOrderFunctionsExamplesUnitTest.scala

@@ -0,0 +1,82 @@
+package com.baeldung.scala
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+
+class HigherOrderFunctionsExamplesUnitTest {
+
+  @Test
+  def whenCallingMapWithAnonymousFunction_thenTransformationIsApplied() = {
+    val expected = Seq("sir Alex Ferguson", "sir Bobby Charlton", "sir Frank Lampard")
+
+    val names = Seq("Alex Ferguson", "Bobby Charlton", "Frank Lampard")
+    val sirNames = names.map(name => "sir " + name)
+
+    assertEquals(expected, sirNames)
+  }
+
+  @Test
+  def whenCallingMapWithDefined_thenTransformationIsApplied() = {
+    val expected = Seq("sir Alex Ferguson", "sir Bobby Charlton", "sir Frank Lampard")
+
+    val names = Seq("Alex Ferguson", "Bobby Charlton", "Frank Lampard")
+
+    def prefixWithSir(name: String) = "sir " + name
+    val sirNames = names.map(prefixWithSir)
+
+    assertEquals(expected, sirNames)
+  }
+
+  @Test
+  def whenCallingFilter_thenUnecessaryElementsAreRemoved() = {
+    val expected = Seq("John O'Shea", "John Hartson")
+
+    val names = Seq("John O'Shea", "Aiden McGeady", "John Hartson")
+    val johns = names.filter(name => name.matches("^John .*"))
+
+    assertEquals(expected, johns)
+  }
+
+  @Test
+  def whenCallingReduce_thenProperSumIsCalculated() = {
+    val expected = 2750
+
+    val earnings = Seq(1000, 1300, 450)
+    val sumEarnings = earnings.reduce((acc, x) => acc + x)
+
+    assertEquals(expected, sumEarnings)
+  }
+
+  @Test
+  def whenCallingFold_thenNumberOfWordsShouldBeCalculated() = {
+    val expected = 6
+
+    val strings = Seq("bunch of words", "just me", "it")
+    val sumEarnings = strings.foldLeft(0)((acc, x) => acc + x.split(" ").size)
+
+    assertEquals(expected, sumEarnings)
+  }
+
+  @Test
+  def whenCallingOwnHigherOrderFunction_thenProperFunctionIsReturned() = {
+    def mathOperation(name: String): (Int, Int) => Int = (x: Int, y: Int) => {
+      name match {
+        case "addition" => x + y
+        case "multiplication" => x * y
+        case "division" => x/y
+        case "subtraction" => x - y
+      }
+    }
+
+    def add: (Int, Int) => Int = mathOperation("addition")
+    def mul: (Int, Int) => Int = mathOperation("multiplication")
+    def div: (Int, Int) => Int = mathOperation("division")
+    def sub: (Int, Int) => Int = mathOperation("subtraction")
+
+    assertEquals(15, add(10, 5))
+    assertEquals(50, mul(10, 5))
+    assertEquals(2, div(10, 5))
+    assertEquals(5, sub(10, 5))
+  }
+}

core-scala/src/test/scala/com/baeldung/scala/regex/RegexUnitTest.scala

@@ -1,4 +1,4 @@
-package com.baeldung.scala
+package com.baeldung.scala.regex
 
 import org.junit.Test
 import org.junit.Assert.assertEquals

ddd/pom.xml

@@ -20,6 +20,10 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-data-mongodb</artifactId>
         </dependency>
+        <dependency>
+        	<groupId>org.springframework.boot</groupId>
+        	<artifactId>spring-boot-starter-data-cassandra</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>

ddd/src/main/java/com/baeldung/dddhexagonalspring/DomainLayerApplication.java

@@ -1,13 +1,37 @@
 package com.baeldung.dddhexagonalspring;
 
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.CommandLineRunner;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.WebApplicationType;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.PropertySource;
 
+import com.baeldung.dddhexagonalspring.application.cli.CliOrderController;
+
 @SpringBootApplication
 @PropertySource(value = { "classpath:ddd-layers.properties" })
-public class DomainLayerApplication {
+public class DomainLayerApplication implements CommandLineRunner {
+
     public static void main(final String[] args) {
-        SpringApplication.run(DomainLayerApplication.class, args);
+        SpringApplication application = new SpringApplication(DomainLayerApplication.class);
+        // uncomment to run just the console application
+        // application.setWebApplicationType(WebApplicationType.NONE);
+        application.run(args);
+    }
+
+    @Autowired
+    public CliOrderController orderController;
+
+    @Autowired
+    public ConfigurableApplicationContext context;
+
+    @Override
+    public void run(String... args) throws Exception {
+        orderController.createCompleteOrder();
+        orderController.createIncompleteOrder();
+        // uncomment to stop the context when execution is done
+        // context.close();
     }
 }

ddd/src/main/java/com/baeldung/dddhexagonalspring/application/cli/CliOrderController.java

@@ -0,0 +1,47 @@
+package com.baeldung.dddhexagonalspring.application.cli;
+
+import java.math.BigDecimal;
+import java.util.UUID;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import com.baeldung.dddhexagonalspring.domain.Product;
+import com.baeldung.dddhexagonalspring.domain.service.OrderService;
+
+@Component
+public class CliOrderController {
+
+    private static final Logger LOG = LoggerFactory.getLogger(CliOrderController.class);
+
+    private final OrderService orderService;
+
+    @Autowired
+    public CliOrderController(OrderService orderService) {
+        this.orderService = orderService;
+    }
+
+    public void createCompleteOrder() {
+        LOG.info("<<Create complete order>>");
+        UUID orderId = createOrder();
+        orderService.completeOrder(orderId);
+    }
+
+    public void createIncompleteOrder() {
+        LOG.info("<<Create incomplete order>>");
+        UUID orderId = createOrder();
+    }
+
+    private UUID createOrder() {
+        LOG.info("Placing a new order with two products");
+        Product mobilePhone = new Product(UUID.randomUUID(), BigDecimal.valueOf(200), "mobile");
+        Product razor = new Product(UUID.randomUUID(), BigDecimal.valueOf(50), "razor");
+        LOG.info("Creating order with mobile phone");
+        UUID orderId = orderService.createOrder(mobilePhone);
+        LOG.info("Adding a razor to the order");
+        orderService.addProduct(orderId, razor);
+        return orderId;
+    }
+}

ddd/src/main/java/com/baeldung/dddhexagonalspring/application/rest/OrderController.java

@@ -1,4 +1,4 @@
-package com.baeldung.dddhexagonalspring.application.controller;
+package com.baeldung.dddhexagonalspring.application.rest;
 
 import com.baeldung.dddhexagonalspring.application.request.AddProductRequest;
 import com.baeldung.dddhexagonalspring.application.request.CreateOrderRequest;

ddd/src/main/java/com/baeldung/dddhexagonalspring/domain/Order.java

@@ -4,6 +4,7 @@ import java.math.BigDecimal;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.UUID;
 
 public class Order {
@@ -40,13 +41,11 @@ public class Order {
     }
 
     private OrderItem getOrderItem(final UUID id) {
-        return orderItems
-          .stream()
-          .filter(orderItem -> orderItem
-            .getProductId()
-            .equals(id))
-          .findFirst()
-          .orElseThrow(() -> new DomainException("Product with " + id + " doesn't exist."));
+        return orderItems.stream()
+            .filter(orderItem -> orderItem.getProductId()
+                .equals(id))
+            .findFirst()
+            .orElseThrow(() -> new DomainException("Product with " + id + " doesn't exist."));
     }
 
     private void validateState() {
@@ -77,6 +76,21 @@ public class Order {
         return Collections.unmodifiableList(orderItems);
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, orderItems, price, status);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (!(obj instanceof Order))
+            return false;
+        Order other = (Order) obj;
+        return Objects.equals(id, other.id) && Objects.equals(orderItems, other.orderItems) && Objects.equals(price, other.price) && status == other.status;
+    }
+
     private Order() {
     }
 }

ddd/src/main/java/com/baeldung/dddhexagonalspring/infrastracture/configuration/CassandraConfiguration.java

@@ -0,0 +1,10 @@
+package com.baeldung.dddhexagonalspring.infrastracture.configuration;
+
+import org.springframework.data.cassandra.repository.config.EnableCassandraRepositories;
+
+import com.baeldung.dddhexagonalspring.infrastracture.repository.cassandra.SpringDataCassandraOrderRepository;
+
+@EnableCassandraRepositories(basePackageClasses = SpringDataCassandraOrderRepository.class)
+public class CassandraConfiguration {
+
+}

ddd/src/main/java/com/baeldung/dddhexagonalspring/infrastracture/configuration/MongoDBConfiguration.java

@@ -1,8 +1,9 @@
 package com.baeldung.dddhexagonalspring.infrastracture.configuration;
 
-import com.baeldung.dddhexagonalspring.infrastracture.repository.SpringDataOrderRepository;
 import org.springframework.data.mongodb.repository.config.EnableMongoRepositories;
 
-@EnableMongoRepositories(basePackageClasses = SpringDataOrderRepository.class)
+import com.baeldung.dddhexagonalspring.infrastracture.repository.mongo.SpringDataMongoOrderRepository;
+
+@EnableMongoRepositories(basePackageClasses = SpringDataMongoOrderRepository.class)
 public class MongoDBConfiguration {
 }

ddd/src/main/java/com/baeldung/dddhexagonalspring/infrastracture/repository/cassandra/CassandraDbOrderRepository.java

@@ -0,0 +1,38 @@
+package com.baeldung.dddhexagonalspring.infrastracture.repository.cassandra;
+
+import java.util.Optional;
+import java.util.UUID;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import com.baeldung.dddhexagonalspring.domain.Order;
+import com.baeldung.dddhexagonalspring.domain.repository.OrderRepository;
+
+@Component
+public class CassandraDbOrderRepository implements OrderRepository {
+
+    private final SpringDataCassandraOrderRepository orderRepository;
+
+    @Autowired
+    public CassandraDbOrderRepository(SpringDataCassandraOrderRepository orderRepository) {
+        this.orderRepository = orderRepository;
+    }
+
+    @Override
+    public Optional<Order> findById(UUID id) {
+        Optional<OrderEntity> orderEntity = orderRepository.findById(id);
+        if (orderEntity.isPresent()) {
+            return Optional.of(orderEntity.get()
+                .toOrder());
+        } else {
+            return Optional.empty();
+        }
+    }
+
+    @Override
+    public void save(Order order) {
+        orderRepository.save(new OrderEntity(order));
+    }
+
+}

ddd/src/main/java/com/baeldung/dddhexagonalspring/infrastracture/repository/cassandra/OrderEntity.java

@@ -0,0 +1,75 @@
+package com.baeldung.dddhexagonalspring.infrastracture.repository.cassandra;
+
+import java.math.BigDecimal;
+import java.util.List;
+import java.util.UUID;
+import java.util.stream.Collectors;
+
+import org.springframework.data.cassandra.core.mapping.PrimaryKey;
+
+import com.baeldung.dddhexagonalspring.domain.Order;
+import com.baeldung.dddhexagonalspring.domain.OrderItem;
+import com.baeldung.dddhexagonalspring.domain.OrderStatus;
+import com.baeldung.dddhexagonalspring.domain.Product;
+
+public class OrderEntity {
+
+    @PrimaryKey
+    private UUID id;
+    private OrderStatus status;
+    private List<OrderItemEntity> orderItemEntities;
+    private BigDecimal price;
+
+    public OrderEntity(UUID id, OrderStatus status, List<OrderItemEntity> orderItemEntities, BigDecimal price) {
+        this.id = id;
+        this.status = status;
+        this.orderItemEntities = orderItemEntities;
+        this.price = price;
+    }
+
+    public OrderEntity() {
+    }
+
+    public OrderEntity(Order order) {
+        this.id = order.getId();
+        this.price = order.getPrice();
+        this.status = order.getStatus();
+        this.orderItemEntities = order.getOrderItems()
+            .stream()
+            .map(OrderItemEntity::new)
+            .collect(Collectors.toList());
+
+    }
+
+    public Order toOrder() {
+        List<OrderItem> orderItems = orderItemEntities.stream()
+            .map(OrderItemEntity::toOrderItem)
+            .collect(Collectors.toList());
+        List<Product> namelessProducts = orderItems.stream()
+            .map(orderItem -> new Product(orderItem.getProductId(), orderItem.getPrice(), ""))
+            .collect(Collectors.toList());
+        Order order = new Order(id, namelessProducts.remove(0));
+        namelessProducts.forEach(product -> order.addOrder(product));
+        if (status == OrderStatus.COMPLETED) {
+            order.complete();
+        }
+        return order;
+    }
+
+    public UUID getId() {
+        return id;
+    }
+
+    public OrderStatus getStatus() {
+        return status;
+    }
+
+    public List<OrderItemEntity> getOrderItems() {
+        return orderItemEntities;
+    }
+
+    public BigDecimal getPrice() {
+        return price;
+    }
+
+}

ddd/src/main/java/com/baeldung/dddhexagonalspring/infrastracture/repository/cassandra/OrderItemEntity.java

@@ -0,0 +1,44 @@
+package com.baeldung.dddhexagonalspring.infrastracture.repository.cassandra;
+
+import java.math.BigDecimal;
+import java.util.UUID;
+
+import org.springframework.data.cassandra.core.mapping.UserDefinedType;
+
+import com.baeldung.dddhexagonalspring.domain.OrderItem;
+import com.baeldung.dddhexagonalspring.domain.Product;
+
+@UserDefinedType
+public class OrderItemEntity {
+
+    private UUID productId;
+    private BigDecimal price;
+
+    public OrderItemEntity() {
+    }
+
+    public OrderItemEntity(final OrderItem orderItem) {
+        this.productId = orderItem.getProductId();
+        this.price = orderItem.getPrice();
+    }
+
+    public OrderItem toOrderItem() {
+        return new OrderItem(new Product(productId, price, ""));
+    }
+
+    public UUID getProductId() {
+        return productId;
+    }
+
+    public void setProductId(UUID productId) {
+        this.productId = productId;
+    }
+
+    public BigDecimal getPrice() {
+        return price;
+    }
+
+    public void setPrice(BigDecimal price) {
+        this.price = price;
+    }
+}

ddd/src/main/java/com/baeldung/dddhexagonalspring/infrastracture/repository/cassandra/SpringDataCassandraOrderRepository.java

@@ -0,0 +1,10 @@
+package com.baeldung.dddhexagonalspring.infrastracture.repository.cassandra;
+
+import java.util.UUID;
+
+import org.springframework.data.cassandra.repository.CassandraRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface SpringDataCassandraOrderRepository extends CassandraRepository<OrderEntity, UUID> {
+}

ddd/src/main/java/com/baeldung/dddhexagonalspring/infrastracture/repository/mongo/MongoDbOrderRepository.java

@@ -1,20 +1,23 @@
-package com.baeldung.dddhexagonalspring.infrastracture.repository;
-
-import com.baeldung.dddhexagonalspring.domain.Order;
-import com.baeldung.dddhexagonalspring.domain.repository.OrderRepository;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.stereotype.Component;
+package com.baeldung.dddhexagonalspring.infrastracture.repository.mongo;
 
 import java.util.Optional;
 import java.util.UUID;
 
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Primary;
+import org.springframework.stereotype.Component;
+
+import com.baeldung.dddhexagonalspring.domain.Order;
+import com.baeldung.dddhexagonalspring.domain.repository.OrderRepository;
+
 @Component
+@Primary
 public class MongoDbOrderRepository implements OrderRepository {
 
-    private final SpringDataOrderRepository orderRepository;
+    private final SpringDataMongoOrderRepository orderRepository;
 
     @Autowired
-    public MongoDbOrderRepository(final SpringDataOrderRepository orderRepository) {
+    public MongoDbOrderRepository(final SpringDataMongoOrderRepository orderRepository) {
         this.orderRepository = orderRepository;
     }
 

ddd/src/main/java/com/baeldung/dddhexagonalspring/infrastracture/repository/mongo/SpringDataMongoOrderRepository.java

@@ -1,4 +1,4 @@
-package com.baeldung.dddhexagonalspring.infrastracture.repository;
+package com.baeldung.dddhexagonalspring.infrastracture.repository.mongo;
 
 import com.baeldung.dddhexagonalspring.domain.Order;
 import org.springframework.data.mongodb.repository.MongoRepository;
@@ -7,5 +7,5 @@ import org.springframework.stereotype.Repository;
 import java.util.UUID;
 
 @Repository
-public interface SpringDataOrderRepository extends MongoRepository<Order, UUID> {
+public interface SpringDataMongoOrderRepository extends MongoRepository<Order, UUID> {
 }

ddd/src/main/resources/ddd-layers.properties

@@ -1,5 +1,12 @@
+spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration
 spring.data.mongodb.host=localhost
 spring.data.mongodb.port=27017
 spring.data.mongodb.database=order-database
 spring.data.mongodb.username=order
-spring.data.mongodb.password=order
+spring.data.mongodb.password=order
+
+spring.data.cassandra.keyspaceName=order_database
+spring.data.cassandra.username=cassandra
+spring.data.cassandra.password=cassandra
+spring.data.cassandra.contactPoints=localhost
+spring.data.cassandra.port=9042

ddd/src/test/java/com/baeldung/dddhexagonalspring/infrastracture/repository/CassandraDbOrderRepositoryIntegrationTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.dddhexagonalspring.infrastracture.repository;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.math.BigDecimal;
+import java.util.Optional;
+import java.util.UUID;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+
+import com.baeldung.dddhexagonalspring.domain.Order;
+import com.baeldung.dddhexagonalspring.domain.Product;
+import com.baeldung.dddhexagonalspring.domain.repository.OrderRepository;
+import com.baeldung.dddhexagonalspring.infrastracture.repository.cassandra.SpringDataCassandraOrderRepository;
+
+@SpringJUnitConfig
+@SpringBootTest
+@TestPropertySource("classpath:ddd-layers-test.properties")
+class CassandraDbOrderRepositoryIntegrationTest {
+
+    @Autowired
+    private SpringDataCassandraOrderRepository cassandraOrderRepository;
+
+    @Autowired
+    private OrderRepository orderRepository;
+
+    @AfterEach
+    void cleanUp() {
+        cassandraOrderRepository.deleteAll();
+    }
+
+    @Test
+    void shouldFindById_thenReturnOrder() {
+
+        // given
+        final UUID id = UUID.randomUUID();
+        final Order order = createOrder(id);
+        order.addOrder(new Product(UUID.randomUUID(), BigDecimal.TEN, "second"));
+        order.complete();
+
+        // when
+        orderRepository.save(order);
+
+        final Optional<Order> result = orderRepository.findById(id);
+
+        assertEquals(order, result.get());
+    }
+
+    private Order createOrder(UUID id) {
+        return new Order(id, new Product(UUID.randomUUID(), BigDecimal.TEN, "product"));
+    }
+}

ddd/src/test/java/com/baeldung/dddhexagonalspring/infrastracture/repository/MongoDbOrderRepositoryIntegrationTest.java

@@ -0,0 +1,55 @@
+package com.baeldung.dddhexagonalspring.infrastracture.repository;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.math.BigDecimal;
+import java.util.Optional;
+import java.util.UUID;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+
+import com.baeldung.dddhexagonalspring.domain.Order;
+import com.baeldung.dddhexagonalspring.domain.Product;
+import com.baeldung.dddhexagonalspring.domain.repository.OrderRepository;
+import com.baeldung.dddhexagonalspring.infrastracture.repository.mongo.SpringDataMongoOrderRepository;
+
+@SpringJUnitConfig
+@SpringBootTest
+@TestPropertySource("classpath:ddd-layers-test.properties")
+class MongoDbOrderRepositoryIntegrationTest {
+
+    @Autowired
+    private SpringDataMongoOrderRepository mongoOrderRepository;
+
+    @Autowired
+    private OrderRepository orderRepository;
+
+    @AfterEach
+    void cleanUp() {
+        mongoOrderRepository.deleteAll();
+    }
+
+    @Test
+    void shouldFindById_thenReturnOrder() {
+
+        // given
+        final UUID id = UUID.randomUUID();
+        final Order order = createOrder(id);
+
+        // when
+        orderRepository.save(order);
+
+        final Optional<Order> result = orderRepository.findById(id);
+
+        assertEquals(order, result.get());
+    }
+
+    private Order createOrder(UUID id) {
+        return new Order(id, new Product(UUID.randomUUID(), BigDecimal.TEN, "product"));
+    }
+}

ddd/src/test/java/com/baeldung/dddhexagonalspring/infrastracture/repository/MongoDbOrderRepositoryUnitTest.java

@@ -2,6 +2,9 @@ package com.baeldung.dddhexagonalspring.infrastracture.repository;
 
 import com.baeldung.dddhexagonalspring.domain.Order;
 import com.baeldung.dddhexagonalspring.domain.Product;
+import com.baeldung.dddhexagonalspring.infrastracture.repository.mongo.MongoDbOrderRepository;
+import com.baeldung.dddhexagonalspring.infrastracture.repository.mongo.SpringDataMongoOrderRepository;
+
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
@@ -14,12 +17,12 @@ import static org.mockito.Mockito.*;
 
 class MongoDbOrderRepositoryUnitTest {
 
-    private SpringDataOrderRepository springDataOrderRepository;
+    private SpringDataMongoOrderRepository springDataOrderRepository;
     private MongoDbOrderRepository tested;
 
     @BeforeEach
-    void setUp(){
-        springDataOrderRepository = mock(SpringDataOrderRepository.class);
+    void setUp() {
+        springDataOrderRepository = mock(SpringDataMongoOrderRepository.class);
 
         tested = new MongoDbOrderRepository(springDataOrderRepository);
     }

ddd/src/test/resources/com/baeldung/dddhexagonalspring/README.md

@@ -4,4 +4,6 @@ To run this project, follow these steps:
 
 * Run the application database by executing `docker-compose up` in this directory.
 * Launch the Spring Boot Application (DomainLayerApplication). 
-* By default, application will connect to this database (configuration in *ddd-layers.properties*)
+* By default, the application will connect to the one of the two databases (configuration in *ddd-layers.properties*)
+     * check `CassandraDbOrderRepository.java` and `MongoDbOrderRepository.java` 
+     * switch between the databases by making one of the above beans primary using the `@Primary` annotation  

ddd/src/test/resources/com/baeldung/dddhexagonalspring/cassandra-init.cql

@@ -0,0 +1,12 @@
+CREATE KEYSPACE IF NOT exists order_database
+WITH replication = {'class':'SimpleStrategy', 'replication_factor':1};
+
+CREATE TYPE IF NOT EXISTS order_database.orderitementity (productid uuid, price decimal); 
+
+CREATE TABLE IF NOT EXISTS order_database.orderentity(
+   id uuid,
+   status text,
+   orderitementities list<frozen<orderitementity>>,
+   price decimal,
+   primary key(id)
+);

ddd/src/test/resources/com/baeldung/dddhexagonalspring/docker-compose.yml

@@ -3,6 +3,7 @@ version: '3'
 services:
   order-mongo-database:
     image: mongo:3.4.13
+    container_name: order-mongo-db
     restart: always
     ports:
       - 27017:27017
@@ -11,4 +12,19 @@ services:
       MONGO_INITDB_ROOT_PASSWORD: admin
       MONGO_INITDB_DATABASE: order-database
     volumes:
-      - ./mongo-init.js:/docker-entrypoint-initdb.d/mongo-init.js:ro
+      - ./mongo-init.js:/docker-entrypoint-initdb.d/mongo-init.js:ro
+  order-cassandra-database:
+    image: cassandra:3.11.5
+    container_name: order-cassandra-db
+    restart: always
+    ports: 
+      - 9042:9042
+  order-cassandra-init:
+    image: cassandra:3.11.5
+    container_name: order-cassandra-db-init
+    depends_on:
+      - order-cassandra-database
+    volumes:
+      - ./cassandra-init.cql:/cassandra-init.cql:ro
+    command: bin/bash -c "echo Initializing cassandra schema... && sleep 30 && cqlsh -u cassandra -p cassandra -f cassandra-init.cql order-cassandra-db" 
+      

ddd/src/test/resources/ddd-layers-test.properties

@@ -0,0 +1,12 @@
+spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration,org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration 
+spring.data.mongodb.host=127.0.0.1
+spring.data.mongodb.port=27017
+spring.data.mongodb.database=order-database
+spring.data.mongodb.username=order
+spring.data.mongodb.password=order
+
+spring.data.cassandra.keyspaceName=order_database
+spring.data.cassandra.username=cassandra
+spring.data.cassandra.password=cassandra
+spring.data.cassandra.contactPoints=127.0.0.1
+spring.data.cassandra.port=9042

gradle-6/.gitignore

@@ -0,0 +1,18 @@
+
+# Gradle
+
+.gradle
+build
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
+
+# # Work around https://youtrack.jetbrains.com/issue/IDEA-116898
+# gradle/wrapper/gradle-wrapper.properties
+

gradle-6/build.gradle.kts

@@ -0,0 +1,5 @@
+subprojects {
+    repositories {
+        mavenCentral()
+    }
+}

gradle-6/configuration-avoidance/build.gradle.kts

@@ -0,0 +1,37 @@
+plugins {
+    base
+}
+
+description = """
+    Demonstrates Gradle Configuraiton Avoidance API. Creates a new configuration "extralibs" to 
+    which we add dependencies. The custom task "copyExtraLibs" copies those dependencies to a new 
+    build directory "extra-libs". This build uses the Task Configuraion Avoidance APIs which have 
+    been marked stable in Gradle 6.0
+""".trimIndent()
+
+// extraLibs is a NamedDomainObjectProvider<Configuration!> - the Configuration object will not be
+// realized until it is needed. In the meantime, the build may reference it by name
+val extralibs by configurations.registering
+
+dependencies {
+    // we can call extralibs.name without causing the extralibs to be realized
+    add(extralibs.name, "junit:junit:4.12")
+}
+
+// extraLibsDir is a Provider<Directory!> - the Directory object will not be realized until it is
+// needed
+val extraLibsDir = project.layout.buildDirectory.dir("extra-libs")
+
+// copyExtraLibs is a TaskProvider<Copy!> - the task will not be realized until it is needed
+val copyExtraLibs by tasks.registering(Copy::class) {
+    // the copy task's "from" and "into" APIs accept Provider types to support configuration
+    // avoidance
+    from(extralibs)
+    into(extraLibsDir)
+}
+
+// configures the "build" task only if it needs to be
+tasks.build {
+    // dependsOn accepts a TaskProvider to avoid realizing the copyExtraLibs needlessly
+    dependsOn(copyExtraLibs)
+}

gradle-6/dependency-constraints/build.gradle.kts

@@ -0,0 +1,29 @@
+plugins {
+    `java-library`
+}
+
+group = "com.baeldung"
+version = "1.0.0"
+
+dependencies {
+    api("io.reactivex.rxjava2:rxjava:2.2.16")
+    implementation("com.google.guava:guava") {
+        version {
+            require("10.0")
+            prefer("28.1-jre")
+            because("Only uses ImmutableList type, so any version since 2.0 will do, but tested with 28.1-jre")
+        }
+    }
+
+    testImplementation("org.junit.jupiter:junit-jupiter-api:5.5.2")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.5.2")
+}
+
+tasks.compileJava {
+    sourceCompatibility = "1.8"
+    targetCompatibility = "1.8"
+}
+
+tasks.test {
+    useJUnitPlatform()
+}

gradle-6/dependency-constraints/src/main/java/com/baeldung/gradle/RxHelloWorld.java

@@ -0,0 +1,24 @@
+package com.baeldung.gradle;
+
+import com.google.common.collect.ImmutableList;
+import io.reactivex.Observable;
+
+import java.util.List;
+
+/**
+ * Demonstrates a library type that returns an RxJava type.
+ */
+public class RxHelloWorld {
+
+    /**
+     * @return an {@link Observable} that emits events "hello" and "world" before completing.
+     */
+    public static Observable<String> hello() {
+        // Guava ImmutableList class is an implementation detail.
+        List<String> values = ImmutableList.of("hello", "world");
+        return Observable.fromIterable(values);
+    }
+
+    private RxHelloWorld() {
+    }
+}

gradle-6/dependency-constraints/src/test/java/com/baeldung/gradle/RxHelloWorldUnitTest.java

@@ -0,0 +1,14 @@
+package com.baeldung.gradle;
+
+import org.junit.jupiter.api.Test;
+
+import static com.baeldung.gradle.RxHelloWorld.hello;
+
+/**
+ * Unit test for {@link RxHelloWorld}.
+ */
+final class RxHelloWorldUnitTest {
+    @Test void it_emits_hello_world_values() {
+        hello().test().assertValues("hello", "world").assertComplete();
+    }
+}

gradle-6/fibonacci-recursive/build.gradle.kts

@@ -0,0 +1,17 @@
+plugins {
+    `java-library`
+}
+
+dependencies {
+    api(project(":fibonacci-spi"))
+    compileOnly("com.google.auto.service:auto-service-annotations:1.0-rc6")
+    annotationProcessor("com.google.auto.service:auto-service:1.0-rc6")
+
+    testImplementation(testFixtures(project(":fibonacci-spi")))
+    testImplementation("org.junit.jupiter:junit-jupiter-api:5.5.2")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.5.2")
+}
+
+tasks.test {
+    useJUnitPlatform()
+}

gradle-6/fibonacci-recursive/src/main/java/com/baeldung/fibonacci/impl/RecursiveFibonacci.java

@@ -0,0 +1,20 @@
+package com.baeldung.fibonacci.impl;
+
+import com.baeldung.fibonacci.FibonacciSequenceGenerator;
+import com.google.auto.service.AutoService;
+
+/**
+ * Recursive implementation of the {@link FibonacciSequenceGenerator}.
+ */
+@AutoService(FibonacciSequenceGenerator.class) public final class RecursiveFibonacci implements FibonacciSequenceGenerator {
+
+    @Override public int generate(int nth) {
+        if (nth < 0) {
+            throw new IllegalArgumentException("sequence number must be 0 or greater");
+        }
+        if (nth <= 1) {
+            return nth;
+        }
+        return generate(nth - 1) + generate(nth - 2);
+    }
+}

gradle-6/fibonacci-recursive/src/test/java/com/baeldung/fibonacci/impl/RecursiveFibonacciUnitTest.java

@@ -0,0 +1,13 @@
+package com.baeldung.fibonacci.impl;
+
+import com.baeldung.fibonacci.FibonacciSequenceGenerator;
+import com.baeldung.fibonacci.FibonacciSequenceGeneratorFixture;
+
+/**
+ * Unit test which reuses the {@link FibonacciSequenceGeneratorFixture} test mix-in exported from the fibonacci-spi project.
+ */
+final class RecursiveFibonacciUnitTest implements FibonacciSequenceGeneratorFixture {
+    @Override public FibonacciSequenceGenerator provide() {
+        return new RecursiveFibonacci();
+    }
+}

gradle-6/fibonacci-spi/build.gradle.kts

@@ -0,0 +1,13 @@
+plugins {
+    `java-library`
+    `java-test-fixtures`
+}
+
+dependencies {
+    testFixturesApi("org.junit.jupiter:junit-jupiter-api:5.5.2")
+    testFixturesImplementation("org.junit.jupiter:junit-jupiter-engine:5.5.2")
+}
+
+tasks.test {
+    useJUnitPlatform()
+}

gradle-6/fibonacci-spi/src/main/java/com/baeldung/fibonacci/FibonacciSequenceGenerator.java

@@ -0,0 +1,13 @@
+package com.baeldung.fibonacci;
+
+/**
+ * Describes an SPI for a Fibonacci sequence generator function.
+ */
+public interface FibonacciSequenceGenerator {
+
+    /**
+     * @param nth the index of the number in the fibonacci sequence
+     * @return the nth number in the fibonacci sequence
+     */
+    int generate(int nth);
+}

gradle-6/fibonacci-spi/src/testFixtures/java/com/baeldung/fibonacci/FibonacciSequenceGeneratorFixture.java

@@ -0,0 +1,30 @@
+package com.baeldung.fibonacci;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+/**
+ * Reusable test fixture for {@link FibonacciSequenceGenerator} implementations. Tests will be skipped if no such implementation exists.
+ */
+public interface FibonacciSequenceGeneratorFixture {
+
+    /**
+     * @return the implementation of {@link FibonacciSequenceGenerator} to test. Must not be null
+     */
+    FibonacciSequenceGenerator provide();
+
+    @Test default void when_sequence_index_is_negative_then_throws() {
+        final FibonacciSequenceGenerator generator = provide();
+        assertThrows(IllegalArgumentException.class, () -> generator.generate(-1));
+    }
+
+    @Test default void when_given_index_then_generates_fibonacci_number() {
+        final FibonacciSequenceGenerator generator = provide();
+        final int[] sequence = { 0, 1, 1, 2, 3, 5, 8 };
+        for (int i = 0; i < sequence.length; i++) {
+            assertEquals(sequence[i], generator.generate(i));
+        }
+    }
+}

gradle-6/gradle.properties

@@ -0,0 +1,2 @@
+org.gradle.parallel=true
+org.gradle.configureondemand=true

gradle-6/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.0.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradle-6/gradlew

@@ -0,0 +1,183 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

gradle-6/gradlew.bat

@@ -0,0 +1,100 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

gradle-6/httpclient-platform/build.gradle.kts

@@ -0,0 +1,11 @@
+plugins {
+    `java-platform`
+}
+
+dependencies {
+    constraints {
+        api("org.apache.httpcomponents:fluent-hc:4.5.10")
+        api("org.apache.httpcomponents:httpclient:4.5.10")
+        runtime("commons-logging:commons-logging:1.2")
+    }
+}

gradle-6/module-metadata-publishing/build.gradle.kts

@@ -0,0 +1,12 @@
+plugins {
+    java
+    `maven-publish`
+}
+
+publishing {
+    publications {
+        register<MavenPublication>("mavenJava") {
+            from(components["java"])
+        }
+    }
+}

gradle-6/person-rest-client/build.gradle.kts

@@ -0,0 +1,8 @@
+plugins {
+    `java-library`
+}
+
+dependencies {
+    api(platform(project(":httpclient-platform")))
+    implementation("org.apache.httpcomponents:fluent-hc")
+}

gradle-6/settings.gradle.kts

@@ -0,0 +1,10 @@
+rootProject.name = "gradle-6"
+
+include("configuration-avoidance")
+include("dependency-constraints")
+include("fibonacci-spi")
+include("fibonacci-recursive")
+include("httpclient-platform")
+include("module-metadata-publishing")
+include("person-rest-client")
+include("widget-rest-client")

gradle-6/widget-rest-client/build.gradle.kts

@@ -0,0 +1,8 @@
+plugins {
+    `java-library`
+}
+
+dependencies {
+    api(platform(project(":httpclient-platform")))
+    implementation("org.apache.httpcomponents:httpclient")
+}

java-numbers-3/pom.xml

@@ -12,15 +12,32 @@
         <version>0.0.1-SNAPSHOT</version>
         <relativePath>../parent-java</relativePath>
     </parent>
-    
+
     <dependencies>
-    	<dependency>
+        <dependency>
             <groupId>it.unimi.dsi</groupId>
             <artifactId>dsiutils</artifactId>
             <version>${dsiutils.version}</version>
         </dependency>
+        <dependency>
+            <groupId>io.vavr</groupId>
+            <artifactId>vavr</artifactId>
+            <version>${vavr.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
-   
+
     <build>
         <finalName>java-numbers-3</finalName>
         <resources>
@@ -33,6 +50,9 @@
 
     <properties>
         <dsiutils.version>2.6.0</dsiutils.version>
+        <vavr.version>0.10.2</vavr.version>
+        <commons.version>3.9</commons.version>
+        <assertj.version>3.6.1</assertj.version>
     </properties>
 
 </project>

java-numbers-3/src/test/java/com/baeldung/parsedouble/StringToDoubleParserUnitTest.java

@@ -0,0 +1,149 @@
+package com.baeldung.parsedouble;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Optional;
+
+import org.apache.commons.lang3.math.NumberUtils;
+import org.junit.Test;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.primitives.Doubles;
+
+import io.vavr.control.Try;
+
+public class StringToDoubleParserUnitTest {
+
+    @Test
+    public void givenNullValue_whenParseStringToDouble_thenDefaultNaNValueIsReturned() {
+        assertThat(parseStringToDouble(null)).isNaN();
+    }
+
+    @Test
+    public void givenEmptyStringValue_whenParseStringToDouble_thenDefaultNaNValueIsReturned() {
+        assertThat(parseStringToDouble("")).isNaN();
+    }
+
+    @Test
+    public void givenStringValue_whenParseStringToDouble_thenDoubleValueIsReturned() {
+        assertThat(parseStringToDouble("1")).isEqualTo(1.0d);
+    }
+
+    @Test
+    public void givenStringValue_whenParseStringToDoubleWithDefault_thenDoubleValueIsReturned() {
+        assertThat(parseStringToDouble("1", 2.0d)).isEqualTo(1.0d);
+    }
+
+    @Test
+    public void givenEmptyStringValue_whenParseStringToDoubleWithDefault_thenDefaultValueIsReturned() {
+        assertThat(parseStringToDouble("", 1.0d)).isEqualTo(1.0d);
+    }
+
+    @Test
+    public void givenNullValue_whenParseStringToDoubleWithDefault_thenDefaultValueIsReturned() {
+        assertThat(parseStringToDouble(null, 1.0d)).isEqualTo(1.0d);
+    }
+
+    @Test
+    public void givenStringValue_whenParseStringToOptionalDouble_thenOptionalValueIsReturned() {
+        assertThat(parseStringToOptionalDouble("1")).isEqualTo(Optional.of(1.0d));
+    }
+
+    @Test
+    public void givenNullValue_whenParseStringToOptionalDouble_thenOptionalValueIsEmpty() {
+        assertThat(parseStringToOptionalDouble(null)).isEqualTo(Optional.empty());
+    }
+
+    @Test
+    public void givenEmptyStringValue_whenParseStringToOptionalDouble_thenOptionalValueIsEmpty() {
+        assertThat(parseStringToOptionalDouble("")).isEqualTo(Optional.empty());
+    }
+
+    @Test
+    public void givenEmptyStringValue_whenParseStringToOptionalDouble_thenDefaulOptionalValueIsReturned() {
+        assertThat(parseStringToOptionalDouble("").orElse(1.0d)).isEqualTo(1.0d);
+    }
+
+    @Test
+    public void givenNullValue_whenParseStringToOptionalDouble_thenDefaulOptionalValueIsReturned() {
+        assertThat(parseStringToOptionalDouble(null).orElse(1.0d)).isEqualTo(1.0d);
+    }
+
+    @Test
+    public void givenStringValue_whenTryStringToDouble_thenDoubleValueIsReturned() {
+        assertThat(tryStringToDouble("1", 2.0d)).isEqualTo(1.0d);
+    }
+
+    @Test
+    public void givenNullValue_whenTryStringToDoubleWithDefault_thenDoubleValueIsReturned() {
+        assertThat(tryStringToDouble(null, 2.0d)).isEqualTo(2.0d);
+    }
+
+    @Test
+    public void givenEmptyStringValue_whenTryStringToDoubleWithDefault_thenDoubleValueIsReturned() {
+        assertThat(tryStringToDouble("", 2.0d)).isEqualTo(2.0d);
+    }
+
+    @Test
+    public void givenTwoStringValues_whenTryParseFirstNonNull_thenDoubleValueIsReturned() {
+        assertThat(Doubles.tryParse(MoreObjects.firstNonNull("1.0", "2.0"))).isEqualTo(1.0d);
+    }
+
+    @Test
+    public void givenNullStringValue_whenTryParseFirstNonNull_thenSecondDoubleValueIsReturned() {
+        assertThat(Doubles.tryParse(MoreObjects.firstNonNull(null, "2.0"))).isEqualTo(2.0d);
+    }
+
+    @Test
+    public void givenEmptyStringValue_whenTryParseFirstNonNull_thenNullIsReturned() {
+        assertThat(Doubles.tryParse(MoreObjects.firstNonNull("", "2.0"))).isEqualTo(null);
+    }
+
+    @Test
+    public void givenStringValue_whenToDouble_thenDoubleValueIsReturned() {
+        assertThat(NumberUtils.toDouble("1.0")).isEqualTo(1.0d);
+    }
+
+    @Test
+    public void givenNullValue_whenToDouble_thenLibraryDefaultDoubleValueIsReturned() {
+        String nullString = null;
+        assertThat(NumberUtils.toDouble(nullString)).isEqualTo(0.0d);
+    }
+
+    @Test
+    public void givenEmptyStringValue_whenToDouble_thenLibraryDefaultDoubleValueIsReturned() {
+        assertThat(NumberUtils.toDouble("")).isEqualTo(0.0d);
+    }
+
+    @Test
+    public void givenEmptyStringValue_whenToDoubleWithDefault_thenDoubleValueIsReturned() {
+        assertThat(NumberUtils.toDouble("", 2.0d)).isEqualTo(2.0d);
+    }
+
+    @Test
+    public void givenNullValue_whenToDoubleWithDefault_thenDoubleValueIsReturned() {
+        String nullString = null;
+        assertThat(NumberUtils.toDouble(nullString, 2.0d)).isEqualTo(2.0d);
+    }
+
+    @Test
+    public void givenStringValue_whenToDoubleWithDefault_thenDoubleValueIsReturned() {
+        assertThat(NumberUtils.toDouble("1.0", 2.0d)).isEqualTo(1.0d);
+    }
+
+    private static Optional<Double> parseStringToOptionalDouble(String value) {
+        return value == null || value.isEmpty() ? Optional.empty() : Optional.of(Double.valueOf(value));
+    }
+
+    private static double parseStringToDouble(String value) {
+        return value == null || value.isEmpty() ? Double.NaN : Double.parseDouble(value);
+    }
+
+    private static double parseStringToDouble(String value, double defaultValue) {
+        return value == null || value.isEmpty() ? defaultValue : Double.parseDouble(value);
+    }
+
+    private static double tryStringToDouble(String value, double defaultValue) {
+        return Try.of(() -> Double.parseDouble(value)).getOrElse(defaultValue);
+    }
+}

libraries-3/pom.xml

@@ -73,6 +73,28 @@
             <version>${cache2k.version}</version>
             <type>pom</type>
         </dependency>
+        <dependency>
+            <groupId>com.squareup.moshi</groupId>
+            <artifactId>moshi</artifactId>
+            <version>${moshi.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.squareup.moshi</groupId>
+            <artifactId>moshi-adapters</artifactId>
+            <version>${moshi.version}</version>
+        </dependency>
+        
+        <dependency>
+            <groupId>com.jcabi</groupId>
+            <artifactId>jcabi-aspects</artifactId>
+            <version>${jcabi-aspects.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.aspectj</groupId>
+            <artifactId>aspectjrt</artifactId>
+            <version>${aspectjrt.version}</version>
+            <scope>runtime</scope>
+        </dependency>
     </dependencies>
 
     <repositories>
@@ -81,6 +103,36 @@
             <url>https://jitpack.io</url>
         </repository>
     </repositories>
+    
+    <build>
+        <finalName>libraries-3</finalName>
+        <plugins>
+            <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>
+    </build>
 
     <properties>
         <jcommander.version>1.78</jcommander.version>
@@ -93,5 +145,11 @@
         <cactoos.version>0.43</cactoos.version>
         <airline.version>2.7.2</airline.version>
         <cache2k.version>1.2.3.Final</cache2k.version>
+        <moshi.version>1.9.2</moshi.version>
+        <jcabi-aspects.version>0.22.6</jcabi-aspects.version>
+        <aspectjrt.version>1.9.2</aspectjrt.version>
+        <jcabi-maven-plugin.version>0.14.1</jcabi-maven-plugin.version>
+        <aspectjtools.version>1.9.2</aspectjtools.version>
+        <aspectjweaver.version>1.9.2</aspectjweaver.version>
     </properties>
 </project>

libraries-3/src/main/java/com/baeldung/cache2k/ProductHelper.java

@@ -4,38 +4,33 @@ import java.util.Objects;
 
 import org.cache2k.Cache;
 import org.cache2k.Cache2kBuilder;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class ProductHelper {
 
-    final Logger LOGGER = LoggerFactory.getLogger(ProductHelper.class);
-
     private Cache<String, Integer> cachedDiscounts;
 
+    private int cacheMissCount = 0;
+
     public ProductHelper() {
         cachedDiscounts = Cache2kBuilder.of(String.class, Integer.class)
             .name("discount")
             .eternal(true)
             .entryCapacity(100)
             .build();
-
-        initDiscountCache("Sports", 20);
-    }
-
-    public void initDiscountCache(String productType, Integer value) {
-        cachedDiscounts.put(productType, value);
     }
 
     public Integer getDiscount(String productType) {
         Integer discount = cachedDiscounts.get(productType);
         if (Objects.isNull(discount)) {
-            LOGGER.info("Discount for {} not found.", productType);
-            discount = 0;
-        } else {
-            LOGGER.info("Discount for {} found.", productType);
+            cacheMissCount++;
+            discount = "Sports".equalsIgnoreCase(productType) ? 20 : 10;
+            cachedDiscounts.put(productType, discount);
         }
         return discount;
     }
 
+    public int getCacheMissCount() {
+        return cacheMissCount;
+    }
+
 }

libraries-3/src/main/java/com/baeldung/cache2k/ProductHelperUsingLoader.java

@@ -1,6 +1,5 @@
 package com.baeldung.cache2k;
 
-import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
 import org.cache2k.Cache;
@@ -14,28 +13,26 @@ public class ProductHelperUsingLoader {
 
     private Cache<String, Integer> cachedDiscounts;
 
+    private int cacheMissCount = 0;
+
     public ProductHelperUsingLoader() {
         cachedDiscounts = Cache2kBuilder.of(String.class, Integer.class)
             .name("discount-loader")
-            .eternal(false)
             .expireAfterWrite(10, TimeUnit.MILLISECONDS)
             .entryCapacity(100)
             .loader((key) -> {
-                LOGGER.info("Calculating discount for {}.", key);
+                cacheMissCount++;
                 return "Sports".equalsIgnoreCase(key) ? 20 : 10;
             })
             .build();
     }
 
     public Integer getDiscount(String productType) {
-        Integer discount = cachedDiscounts.get(productType);
-        if (Objects.isNull(discount)) {
-            LOGGER.info("Discount for {} not found.", productType);
-            discount = 0;
-        } else {
-            LOGGER.info("Discount for {} found.", productType);
-        }
-        return discount;
+        return cachedDiscounts.get(productType);
+    }
+
+    public int getCacheMissCount() {
+        return cacheMissCount;
     }
 
 }

libraries-3/src/main/java/com/baeldung/cache2k/ProductHelperWithEventListener.java

@@ -1,6 +1,5 @@
 package com.baeldung.cache2k;
 
-import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
 import org.cache2k.Cache;
@@ -16,14 +15,15 @@ public class ProductHelperWithEventListener {
 
     private Cache<String, Integer> cachedDiscounts;
 
+    private int cacheMissCount = 0;
+
     public ProductHelperWithEventListener() {
         cachedDiscounts = Cache2kBuilder.of(String.class, Integer.class)
             .name("discount-listener")
-            .eternal(false)
             .expireAfterWrite(10, TimeUnit.MILLISECONDS)
             .entryCapacity(100)
             .loader((key) -> {
-                LOGGER.info("Calculating discount for {}.", key);
+                cacheMissCount++;
                 return "Sports".equalsIgnoreCase(key) ? 20 : 10;
             })
             .addListener(new CacheEntryCreatedListener<String, Integer>() {
@@ -36,14 +36,11 @@ public class ProductHelperWithEventListener {
     }
 
     public Integer getDiscount(String productType) {
-        Integer discount = cachedDiscounts.get(productType);
-        if (Objects.isNull(discount)) {
-            LOGGER.info("Discount for {} not found.", productType);
-            discount = 0;
-        } else {
-            LOGGER.info("Discount for {} found.", productType);
-        }
-        return discount;
+        return cachedDiscounts.get(productType);
+    }
+
+    public int getCacheMissCount() {
+        return cacheMissCount;
     }
 
 }

libraries-3/src/main/java/com/baeldung/cache2k/ProductHelperWithExpiry.java

@@ -5,39 +5,34 @@ import java.util.concurrent.TimeUnit;
 
 import org.cache2k.Cache;
 import org.cache2k.Cache2kBuilder;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class ProductHelperWithExpiry {
 
-    final Logger LOGGER = LoggerFactory.getLogger(ProductHelperWithExpiry.class);
-
     private Cache<String, Integer> cachedDiscounts;
 
+    private int cacheMissCount = 0;
+
     public ProductHelperWithExpiry() {
         cachedDiscounts = Cache2kBuilder.of(String.class, Integer.class)
             .name("discount-expiry")
-            .eternal(false)
             .expireAfterWrite(5, TimeUnit.MILLISECONDS)
             .entryCapacity(100)
             .build();
 
-        initDiscountCache("Sports", 20);
-    }
-
-    public void initDiscountCache(String productType, Integer value) {
-        cachedDiscounts.put(productType, value);
     }
 
     public Integer getDiscount(String productType) {
         Integer discount = cachedDiscounts.get(productType);
         if (Objects.isNull(discount)) {
-            LOGGER.info("Discount for {} not found.", productType);
-            discount = 0;
-        } else {
-            LOGGER.info("Discount for {} found.", productType);
+            cacheMissCount++;
+            discount = "Sports".equalsIgnoreCase(productType) ? 20 : 10;
+            cachedDiscounts.put(productType, discount);
         }
         return discount;
     }
 
+    public int getCacheMissCount() {
+        return cacheMissCount;
+    }
+
 }

libraries-3/src/main/java/com/baeldung/jcabi/JcabiAspectJ.java

@@ -0,0 +1,112 @@
+package com.baeldung.jcabi;
+
+
+import java.io.BufferedReader;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+
+import com.jcabi.aspects.Async;
+import com.jcabi.aspects.Cacheable;
+import com.jcabi.aspects.LogExceptions;
+import com.jcabi.aspects.Loggable;
+import com.jcabi.aspects.Quietly;
+import com.jcabi.aspects.RetryOnFailure;
+import com.jcabi.aspects.UnitedThrow;
+
+public class JcabiAspectJ {
+
+    public static void main(String[] args) {
+        try {
+            displayFactorial(10);
+            getFactorial(10).get();
+
+            String result = cacheExchangeRates();
+            if (result != cacheExchangeRates()) {
+                System.out.println(result);
+            }
+
+            divideByZero();
+        } catch(Exception e) {
+            e.printStackTrace();
+        }
+
+        divideByZeroQuietly();
+        try {
+            processFile();  
+        } catch(Exception e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    @Loggable
+    @Async
+    public static void displayFactorial(int number) {
+        long result = factorial(number);
+        System.out.println(result);
+    }
+
+    @Loggable
+    @Async
+    public static Future<Long> getFactorial(int number) {
+        Future<Long> factorialFuture = CompletableFuture.supplyAsync(() -> factorial(number));
+        return factorialFuture;
+    }
+
+    /**
+     * 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; 
+    }
+
+    @Loggable
+    @Cacheable(lifetime = 2, unit = TimeUnit.SECONDS)
+    public static String cacheExchangeRates() {
+        String result = null;
+        try {
+            URL exchangeRateUrl = new URL("https://api.exchangeratesapi.io/latest");
+            URLConnection con = exchangeRateUrl.openConnection();
+            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
+            result = in.readLine();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return result;
+    }
+
+    @LogExceptions
+    public static void divideByZero() {
+        int x = 1/0;
+    }
+
+    @RetryOnFailure(attempts = 2, types = {java.lang.NumberFormatException.class})
+    @Quietly
+    public static void divideByZeroQuietly() {
+        int x = 1/0;
+    }
+
+    @UnitedThrow(IllegalStateException.class)
+    public static void processFile() throws IOException, InterruptedException {
+        BufferedReader reader = new BufferedReader(new FileReader("baeldung.txt"));
+        reader.readLine();
+        
+        Thread thread = new Thread();
+        thread.wait(2000);
+    }
+
+}

libraries-3/src/test/java/com/baeldung/cache2k/ProductHelperUnitTest.java

@@ -6,12 +6,13 @@ import org.junit.Test;
 
 public class ProductHelperUnitTest {
 
-    ProductHelper productHelper = new ProductHelper();
-
     @Test
-    public void whenInvokedGetDiscount_thenGetItFromCache() {
+    public void whenInvokedGetDiscountTwice_thenGetItFromCache() {
+        ProductHelper productHelper = new ProductHelper();
+        assertTrue(productHelper.getCacheMissCount() == 0);
         assertTrue(productHelper.getDiscount("Sports") == 20);
-        assertTrue(productHelper.getDiscount("Electronics") == 0);
+        assertTrue(productHelper.getDiscount("Sports") == 20);
+        assertTrue(productHelper.getCacheMissCount() == 1);
     }
 
 }

libraries-3/src/test/java/com/baeldung/cache2k/ProductHelperUsingLoaderUnitTest.java

@@ -6,12 +6,16 @@ import org.junit.Test;
 
 public class ProductHelperUsingLoaderUnitTest {
 
-    ProductHelperUsingLoader productHelper = new ProductHelperUsingLoader();
-
     @Test
-    public void whenInvokedGetDiscount_thenPopulateCache() {
+    public void whenInvokedGetDiscount_thenPopulateCacheUsingLoader() {
+        ProductHelperUsingLoader productHelper = new ProductHelperUsingLoader();
+        assertTrue(productHelper.getCacheMissCount() == 0);
+
         assertTrue(productHelper.getDiscount("Sports") == 20);
+        assertTrue(productHelper.getCacheMissCount() == 1);
+
         assertTrue(productHelper.getDiscount("Electronics") == 10);
+        assertTrue(productHelper.getCacheMissCount() == 2);
     }
 
 }

libraries-3/src/test/java/com/baeldung/cache2k/ProductHelperWithEventListenerUnitTest.java

@@ -6,10 +6,9 @@ import org.junit.Test;
 
 public class ProductHelperWithEventListenerUnitTest {
 
-    ProductHelperWithEventListener productHelper = new ProductHelperWithEventListener();
-
     @Test
     public void whenEntryAddedInCache_thenEventListenerCalled() {
+        ProductHelperWithEventListener productHelper = new ProductHelperWithEventListener();
         assertTrue(productHelper.getDiscount("Sports") == 20);
     }
 

libraries-3/src/test/java/com/baeldung/cache2k/ProductHelperWithExpiryUnitTest.java

@@ -6,13 +6,17 @@ import org.junit.Test;
 
 public class ProductHelperWithExpiryUnitTest {
 
-    ProductHelperWithExpiry productHelper = new ProductHelperWithExpiry();
-
     @Test
-    public void whenInvokedGetDiscountForExpiredProduct_thenNoDiscount() throws InterruptedException {
+    public void whenInvokedGetDiscountAfterExpiration_thenDiscountCalculatedAgain() throws InterruptedException {
+        ProductHelperWithExpiry productHelper = new ProductHelperWithExpiry();
+        assertTrue(productHelper.getCacheMissCount() == 0);
         assertTrue(productHelper.getDiscount("Sports") == 20);
+        assertTrue(productHelper.getCacheMissCount() == 1);
+
         Thread.sleep(20);
-        assertTrue(productHelper.getDiscount("Sports") == 0);
+
+        assertTrue(productHelper.getDiscount("Sports") == 20);
+        assertTrue(productHelper.getCacheMissCount() == 2);
     }
 
 }

libraries-3/src/test/java/com/baeldung/moshi/AlternativeAdapterUnitTest.java

@@ -0,0 +1,105 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.time.Instant;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.JsonQualifier;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class AlternativeAdapterUnitTest {
+    @Test
+    public void whenSerializing_thenAlternativeAdapterUsed() {
+        Moshi moshi = new Moshi.Builder()
+          .add(new EpochMillisAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = jsonAdapter.toJson(new Post("Introduction to Moshi Json", "Baeldung", Instant.now()));
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenAlternativeAdapterUsed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .add(new EpochMillisAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"author\":\"Baeldung\",\"posted\":1582095269204,\"title\":\"Introduction to Moshi Json\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+
+    }
+
+    public static class Post {
+        String title;
+        String author;
+        @EpochMillis Instant posted;
+
+        public Post() {
+        }
+
+        public Post(String title, String author, Instant posted) {
+            this.title = title;
+            this.author = author;
+            this.posted = posted;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        public Instant getPosted() {
+            return posted;
+        }
+
+        public void setPosted(Instant posted) {
+            this.posted = posted;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("posted", posted)
+                .toString();
+        }
+    }
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target({ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD})
+    @JsonQualifier
+    public @interface EpochMillis {
+    }
+
+    public static class EpochMillisAdapter {
+        @ToJson
+        public Long toJson(@EpochMillis Instant input) {
+            return input.toEpochMilli();
+        }
+        @FromJson
+        @EpochMillis
+        public Instant fromJson(Long input) {
+            return Instant.ofEpochMilli(input);
+        }
+
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/ArrayUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.lang.reflect.Type;
+import java.util.Arrays;
+import java.util.List;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.Types;
+import org.junit.Test;
+
+public class ArrayUnitTest {
+    @Test
+    public void whenSerializingList_thenJsonArrayProduced() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        Type type = Types.newParameterizedType(List.class, String.class);
+        JsonAdapter<List<String>> jsonAdapter = moshi.adapter(type);
+
+        String json = jsonAdapter.toJson(Arrays.asList("One", "Two", "Three"));
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializingJsonArray_thenListProduced() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        Type type = Types.newParameterizedType(List.class, String.class);
+        JsonAdapter<List<String>> jsonAdapter = moshi.adapter(type);
+
+        String json = "[\"One\",\"Two\",\"Three\"]";
+        List<String> result = jsonAdapter.fromJson(json);
+        System.out.println(result);
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/ComplexAdapterUnitTest.java

@@ -0,0 +1,94 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.time.LocalDate;
+import java.time.LocalTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import org.junit.Test;
+
+public class ComplexAdapterUnitTest {
+    @Test
+    public void whenSerializing_thenCorrectJsonProduced() {
+        Moshi moshi = new Moshi.Builder()
+          .add(new JsonDateTimeAdapter())
+          .build();
+        JsonAdapter<ZonedDateTime> jsonAdapter = moshi.adapter(ZonedDateTime.class);
+
+        String json = jsonAdapter.toJson(ZonedDateTime.now());
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenCorrectJsonConsumed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .add(new JsonDateTimeAdapter())
+          .build();
+        JsonAdapter<ZonedDateTime> jsonAdapter = moshi.adapter(ZonedDateTime.class);
+
+        String json = "{\"date\":\"2020-02-17\",\"time\":\"07:53:27.064\",\"timezone\":\"Europe/London\"}";
+        ZonedDateTime now = jsonAdapter.fromJson(json);
+        System.out.println(now);
+
+    }
+
+    public static class JsonDateTimeAdapter {
+        @ToJson
+        public JsonDateTime toJson(ZonedDateTime input) {
+            String date = input.toLocalDate().toString();
+            String time = input.toLocalTime().toString();
+            String timezone = input.getZone().toString();
+            return new JsonDateTime(date, time, timezone);
+        }
+        @FromJson
+        public ZonedDateTime fromJson(JsonDateTime input) {
+            LocalDate date = LocalDate.parse(input.getDate());
+            LocalTime time = LocalTime.parse(input.getTime());
+            ZoneId timezone = ZoneId.of(input.getTimezone());
+            return ZonedDateTime.of(date, time, timezone);
+        }
+    }
+    public static class JsonDateTime {
+        private String date;
+        private String time;
+        private String timezone;
+
+        public JsonDateTime() {
+        }
+
+        public JsonDateTime(String date, String time, String timezone) {
+            this.date = date;
+            this.time = time;
+            this.timezone = timezone;
+        }
+
+        public String getDate() {
+            return date;
+        }
+
+        public void setDate(String date) {
+            this.date = date;
+        }
+
+        public String getTime() {
+            return time;
+        }
+
+        public void setTime(String time) {
+            this.time = time;
+        }
+
+        public String getTimezone() {
+            return timezone;
+        }
+
+        public void setTimezone(String timezone) {
+            this.timezone = timezone;
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/DefaultUnitTest.java

@@ -0,0 +1,68 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.time.Instant;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class DefaultUnitTest {
+
+    @Test
+    public void whenDeserializing_thenFieldsGetDefaultValues() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class Post {
+        private String title;
+        private String author;
+        private String posted;
+
+        public Post() {
+            posted = Instant.now().toString();
+        }
+
+        public Post(String title, String author, String posted) {
+            this.title = title;
+            this.author = author;
+            this.posted = posted;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        public String getPosted() {
+            return posted;
+        }
+
+        public void setPosted(String posted) {
+            this.posted = posted;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("posted", posted)
+                .toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/PrimitiveUnitTest.java

@@ -0,0 +1,77 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class PrimitiveUnitTest {
+    @Test
+    public void whenSerializing_thenCorrectJsonProduced() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", "Baeldung", "This is my post");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenCorrectJsonConsumed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"author\":\"Baeldung\",\"text\":\"This is my post\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+
+    public static class Post {
+        private String title;
+        private String author;
+        private String text;
+
+        public Post() {
+        }
+
+        public Post(String title, String author, String text) {
+            this.title = title;
+            this.author = author;
+            this.text = text;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        public String getText() {
+            return text;
+        }
+
+        public void setText(String text) {
+            this.text = text;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("text", text)
+                .toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/RenameUnitTest.java

@@ -0,0 +1,68 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+
+import com.squareup.moshi.Json;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.jupiter.api.Test;
+
+public class RenameUnitTest {
+
+    @Test
+    public void whenSerializing_thenFieldsGetRenamed() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", "Baeldung");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenSerializing_thenRenamedFieldsGetConsumed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"authored_by\":\"Baeldung\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class Post {
+        private String title;
+        @Json(name = "authored_by")
+        private String author;
+
+        public Post() {
+        }
+
+        public Post(String title, String author) {
+            this.title = title;
+            this.author = author;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/SimpleAdapterUnitTest.java

@@ -0,0 +1,129 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class SimpleAdapterUnitTest {
+    @Test
+    public void whenSerializing_thenAdapterUsed() {
+        Moshi moshi = new Moshi.Builder()
+          .add(new AuthorAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", new Author("Baeldung", "baeldung@example.com"), "This is my post");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenAdapterUsed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .add(new AuthorAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"author\":\"Baeldung <baeldung@example.com>\",\"text\":\"This is my post\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class AuthorAdapter {
+        private Pattern pattern = Pattern.compile("^(.*) <(.*)>$");
+        @ToJson
+        public String toJson(Author author) {
+            return author.name + " <" + author.email + ">";
+        }
+
+        @FromJson
+        public Author fromJson(String author) {
+            Matcher matcher = pattern.matcher(author);
+            return matcher.find() ? new Author(matcher.group(1), matcher.group(2)) : null;
+        }
+    }
+
+    public static class Author {
+        private String name;
+        private String email;
+
+        public Author() {
+        }
+
+        public Author(String name, String email) {
+            this.name = name;
+            this.email = email;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+
+        public String getEmail() {
+            return email;
+        }
+
+        public void setEmail(String email) {
+            this.email = email;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("name", name).append("email", email).toString();
+        }
+    }
+    public static class Post {
+        private String title;
+        private Author author;
+        private String text;
+
+        public Post() {
+        }
+
+        public Post(String title, Author author, String text) {
+            this.title = title;
+            this.author = author;
+            this.text = text;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public Author getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(Author author) {
+            this.author = author;
+        }
+
+        public String getText() {
+            return text;
+        }
+
+        public void setText(String text) {
+            this.text = text;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("text", text)
+              .toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/TransientUnitTest.java

@@ -0,0 +1,66 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.jupiter.api.Test;
+
+public class TransientUnitTest {
+
+    @Test
+    public void whenSerializing_thenTransientFieldIgnored() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", "Baeldung");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenTransientFieldIgnored() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"authored_by\":\"Baeldung\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class Post {
+        private String title;
+        private transient String author;
+
+        public Post() {
+        }
+
+        public Post(String title, String author) {
+            this.title = title;
+            this.author = author;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).toString();
+        }
+    }
+}

lombok-custom/pom.xml

@@ -36,12 +36,12 @@
 
     <profiles>
         <profile>
-            <id>default-tools.jar</id>
+            <id>default-profile</id>
             <activation>
-                <property>
-                    <name>java.vendor</name>
-                    <value>Oracle Corporation</value>
-                </property>
+                <activeByDefault>true</activeByDefault>
+                <file>
+                    <exists>${java.home}/../lib/tools.jar</exists>
+                </file>
             </activation>
             <dependencies>
                 <dependency>
@@ -53,6 +53,24 @@
                 </dependency>
             </dependencies>
         </profile>
+        <profile>
+            <id>mac-profile</id>
+            <activation>
+                <activeByDefault>false</activeByDefault>
+                <file>
+                    <exists>${java.home}/../Classes/classes.jar</exists>
+                </file>
+            </activation>
+            <dependencies>
+                <dependency>
+                    <groupId>com.sun</groupId>
+                    <artifactId>tools</artifactId>
+                    <version>${java.version}</version>
+                    <scope>system</scope>
+                    <systemPath>${java.home}/../Classes/classes.jar</systemPath>
+                </dependency>
+            </dependencies>
+        </profile>
     </profiles>
 
     <properties>

persistence-modules/spring-hibernate-3/README.md

@@ -4,8 +4,8 @@ This module contains articles about Spring with Hibernate 3
 
 ### Relevant Articles: 
 
-- [Hibernate 3 with Spring](http://www.baeldung.com/hibernate3-spring)
-- [HibernateException: No Hibernate Session Bound to Thread in Hibernate 3](http://www.baeldung.com/no-hibernate-session-bound-to-thread-exception)
+- [Hibernate 3 with Spring](https://www.baeldung.com/hibernate3-spring)
+- [HibernateException: No Hibernate Session Bound to Thread in Hibernate 3](https://www.baeldung.com/no-hibernate-session-bound-to-thread-exception)
 
 ### Quick Start
 

persistence-modules/spring-hibernate-3/src/main/java/com/baeldung/persistence/dao/AbstractHibernateDao.java

@@ -1,4 +1,4 @@
-package org.baeldung.persistence.dao;
+package com.baeldung.persistence.dao;
 
 import java.io.Serializable;
 import java.util.List;

persistence-modules/spring-hibernate-3/src/main/java/com/baeldung/persistence/dao/EventDao.java

@@ -1,18 +1,18 @@
-package org.baeldung.persistence.dao;
-
-
-import org.baeldung.persistence.model.Event;
-import org.springframework.stereotype.Repository;
-
-@Repository
-public class EventDao extends AbstractHibernateDao<Event> implements IEventDao {
-
-    public EventDao() {
-        super();
-
-        setClazz(Event.class);
-    }
-
-    // API
-
-}
+package com.baeldung.persistence.dao;
+
+
+import com.baeldung.persistence.model.Event;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public class EventDao extends AbstractHibernateDao<Event> implements IEventDao {
+
+    public EventDao() {
+        super();
+
+        setClazz(Event.class);
+    }
+
+    // API
+
+}