Merge remote-tracking branch 'upstream/master'

algorithms/roundUpToHundred/.gitignore

@@ -0,0 +1 @@
+/bin/

algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundred.java

@@ -0,0 +1,20 @@
+package com.java.src;
+
+import java.util.Scanner;
+
+public class RoundUpToHundred {
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        double input = scanner.nextDouble();
+        scanner.close();
+
+        RoundUpToHundred.round(input);
+    }
+
+    static long round(double input) {
+        long i = (long) Math.ceil(input);
+        return ((i + 99) / 100) * 100;
+    };
+
+}

algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundredTest.java

@@ -0,0 +1,14 @@
+package com.java.src;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class RoundUpToHundredTest {
+    @Test
+    public void givenInput_whenRound_thenRoundUpToTheNearestHundred() {
+        assertEquals("Rounded up to hundred", 100, RoundUpToHundred.round(99));
+        assertEquals("Rounded up to three hundred ", 300, RoundUpToHundred.round(200.2));
+        assertEquals("Returns same rounded value", 400, RoundUpToHundred.round(400));
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/rectanglesoverlap/Point.java

@@ -0,0 +1,29 @@
+package com.baeldung.algorithms.rectanglesoverlap;
+
+public class Point {
+
+    private int x;
+    private int y;
+
+    public Point(int x, int y) {
+        this.x = x;
+        this.y = y;
+    }
+
+    public int getX() {
+        return x;
+    }
+
+    public void setX(int x) {
+        this.x = x;
+    }
+
+    public int getY() {
+        return y;
+    }
+
+    public void setY(int y) {
+        this.y = y;
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/rectanglesoverlap/Rectangle.java

@@ -0,0 +1,40 @@
+package com.baeldung.algorithms.rectanglesoverlap;
+
+public class Rectangle {
+
+    private Point bottomLeft;
+    private Point topRight;
+
+    public Rectangle(Point bottomLeft, Point topRight) {
+        this.bottomLeft = bottomLeft;
+        this.topRight = topRight;
+    }
+
+    public Point getBottomLeft() {
+        return bottomLeft;
+    }
+
+    public void setBottomLeft(Point bottomLeft) {
+        this.bottomLeft = bottomLeft;
+    }
+
+    public Point getTopRight() {
+        return topRight;
+    }
+
+    public void setTopRight(Point topRight) {
+        this.topRight = topRight;
+    }
+
+    public boolean isOverlapping(Rectangle other) {
+        // one rectangle is to the top of the other
+        if (this.topRight.getY() < other.bottomLeft.getY() || this.bottomLeft.getY() > other.topRight.getY()) {
+            return false;
+        }
+        // one rectangle is to the left of the other
+        if (this.topRight.getX() < other.bottomLeft.getX() || this.bottomLeft.getX() > other.topRight.getX()) {
+            return false;
+        }
+        return true;
+    }
+}

algorithms/src/test/java/com/baeldung/algorithms/rectanglesoverlap/RectangleUnitTest.java

@@ -0,0 +1,42 @@
+package com.baeldung.algorithms.rectanglesoverlap;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertFalse;
+import org.junit.Test;
+
+import com.baeldung.algorithms.rectanglesoverlap.Point;
+import com.baeldung.algorithms.rectanglesoverlap.Rectangle;
+
+public class RectangleUnitTest {
+
+    @Test
+    public void givenTwoOverlappingRectangles_whenisOverlappingCalled_shouldReturnTrue() {
+        Rectangle rectangle1 = new Rectangle(new Point(2, 1), new Point(4, 3));
+        Rectangle rectangle2 = new Rectangle(new Point(1, 1), new Point(6, 4));
+        assertTrue(rectangle1.isOverlapping(rectangle2));
+
+        rectangle1 = new Rectangle(new Point(-5, -2), new Point(2, 3));
+        rectangle2 = new Rectangle(new Point(-2, -1), new Point(5, 2));
+        assertTrue(rectangle1.isOverlapping(rectangle2));
+
+        rectangle1 = new Rectangle(new Point(-5, 1), new Point(2, 4));
+        rectangle2 = new Rectangle(new Point(-2, -2), new Point(5, 5));
+        assertTrue(rectangle1.isOverlapping(rectangle2));
+    }
+
+    @Test
+    public void givenTwoNonOverlappingRectangles_whenisOverlappingCalled_shouldReturnFalse() {
+        Rectangle rectangle1 = new Rectangle(new Point(-5, 1), new Point(-3, 4));
+        Rectangle rectangle2 = new Rectangle(new Point(-2, -2), new Point(5, 5));
+        assertFalse(rectangle1.isOverlapping(rectangle2));
+
+        rectangle1 = new Rectangle(new Point(-5, 1), new Point(3, 4));
+        rectangle2 = new Rectangle(new Point(-2, -2), new Point(5, -1));
+        assertFalse(rectangle1.isOverlapping(rectangle2));
+
+        rectangle1 = new Rectangle(new Point(-2, 1), new Point(0, 3));
+        rectangle2 = new Rectangle(new Point(3, 1), new Point(5, 4));
+        assertFalse(rectangle1.isOverlapping(rectangle2));
+    }
+
+}

apache-cxf/README.md

@@ -3,3 +3,4 @@
 - [Apache CXF Support for RESTful Web Services](http://www.baeldung.com/apache-cxf-rest-api)
 - [A Guide to Apache CXF with Spring](http://www.baeldung.com/apache-cxf-with-spring)
 - [Introduction to Apache CXF](http://www.baeldung.com/introduction-to-apache-cxf)
+- [Server-Sent Events (SSE) In JAX-RS](https://www.baeldung.com/java-ee-jax-rs-sse)

aws-lambda/pom.xml

@@ -95,7 +95,6 @@
         <gson.version>2.8.2</gson.version>
         <aws-java-sdk.version>1.11.241</aws-java-sdk.version>
         <maven-shade-plugin.version>3.0.0</maven-shade-plugin.version>
-        <maven-dependency-plugin.version>2.10</maven-dependency-plugin.version>
     </properties>
     
 </project>

aws/.gitignore

@@ -1 +1,2 @@
 /target/
+.idea/

aws/pom.xml

@@ -100,26 +100,6 @@
                     </execution>
                 </executions>
             </plugin>
-
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-dependency-plugin</artifactId>
-                <version>${maven-dependency-plugin.version}</version>
-                <executions>
-                    <execution>
-                        <id>copy-dependencies</id>
-                        <phase>test-compile</phase>
-                        <goals>
-                            <goal>copy-dependencies</goal>
-                        </goals>
-                        <configuration>
-                            <includeScope>test</includeScope>
-                            <includeTypes>so,dll,dylib</includeTypes>
-                            <outputDirectory>${project.basedir}/native-libs</outputDirectory>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
         </plugins>
     </build>
 
@@ -144,7 +124,6 @@
         <commons-codec-version>1.10.L001</commons-codec-version>
         <jets3t-version>0.9.4.0006L</jets3t-version>
         <maven-shade-plugin.version>3.0.0</maven-shade-plugin.version>
-        <maven-dependency-plugin.version>2.10</maven-dependency-plugin.version>
     </properties>
 
 </project>

aws/src/main/java/com/baeldung/rds/AWSRDSService.java

@@ -0,0 +1,184 @@
+package com.baeldung.rds;
+
+import com.amazonaws.auth.AWSCredentialsProvider;
+import com.amazonaws.auth.AWSStaticCredentialsProvider;
+import com.amazonaws.auth.BasicAWSCredentials;
+import com.amazonaws.regions.Regions;
+import com.amazonaws.services.rds.AmazonRDS;
+import com.amazonaws.services.rds.AmazonRDSClientBuilder;
+import com.amazonaws.services.rds.model.*;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.sql.*;
+import java.util.List;
+import java.util.Properties;
+import java.util.UUID;
+import java.util.logging.Logger;
+
+public class AWSRDSService {
+
+
+    final static Logger logger = Logger.getLogger(AWSRDSService.class.getName());
+    private AWSCredentialsProvider credentials;
+    private AmazonRDS amazonRDS;
+    private String db_username;
+    private String db_password;
+    private String db_database;
+    private String db_hostname;
+
+    /*
+    * User access key and secret key must be set before execute any operation.
+    * Follow the link on how to get the user access and secret key
+    * https://aws.amazon.com/blogs/security/wheres-my-secret-access-key/
+    * **/
+    public AWSRDSService() throws IOException {
+        //Init RDS client with credentials and region.
+        credentials = new
+                AWSStaticCredentialsProvider(new
+                BasicAWSCredentials("<ACCESS_KEY>",
+                "<SECRET_KEY>"));
+        amazonRDS = AmazonRDSClientBuilder.standard().withCredentials(credentials)
+                .withRegion(Regions.AP_SOUTHEAST_2).build();
+        Properties prop = new Properties();
+        InputStream input = AWSRDSService.class.getClassLoader().getResourceAsStream("db.properties");
+        prop.load(input);
+        db_username = prop.getProperty("db_username");
+        db_password = prop.getProperty("db_password");
+        db_database = prop.getProperty("db_database");
+    }
+
+    public AWSRDSService(AmazonRDS amazonRDS){
+        this.amazonRDS = amazonRDS;
+    }
+
+    /**
+     * create the RDS instance.
+     * After instance creation, update the db_hostname with endpoint in db.properties.
+     * */
+
+    public String launchInstance() {
+
+        String identifier = "";
+        CreateDBInstanceRequest request = new CreateDBInstanceRequest();
+        // RDS instance name
+        request.setDBInstanceIdentifier("Sydney");
+        request.setEngine("postgres");
+        request.setMultiAZ(false);
+        request.setMasterUsername(db_username);
+        request.setMasterUserPassword(db_password);
+        request.setDBName(db_database);
+        request.setStorageType("gp2");
+        request.setAllocatedStorage(10);
+
+        DBInstance instance = amazonRDS.createDBInstance(request);
+
+        // Information about the new RDS instance
+        identifier = instance.getDBInstanceIdentifier();
+        String status = instance.getDBInstanceStatus();
+        Endpoint endpoint = instance.getEndpoint();
+        String endpoint_url = "Endpoint URL not available yet.";
+        if (endpoint != null) {
+            endpoint_url = endpoint.toString();
+        }
+        logger.info(identifier + "\t" + status);
+        logger.info(endpoint_url);
+
+        return identifier;
+
+    }
+
+    // Describe DB instances
+    public void listInstances() {
+        DescribeDBInstancesResult result = amazonRDS.describeDBInstances();
+        List<DBInstance> instances = result.getDBInstances();
+        for (DBInstance instance : instances) {
+            // Information about each RDS instance
+            String identifier = instance.getDBInstanceIdentifier();
+            String engine = instance.getEngine();
+            String status = instance.getDBInstanceStatus();
+            Endpoint endpoint = instance.getEndpoint();
+            String endpoint_url = "Endpoint URL not available yet.";
+            if (endpoint != null) {
+                endpoint_url = endpoint.toString();
+            }
+            logger.info(identifier + "\t" + engine + "\t" + status);
+            logger.info("\t" + endpoint_url);
+        }
+
+    }
+
+    //Delete RDS instance
+    public void terminateInstance(String identifier) {
+
+        DeleteDBInstanceRequest request = new DeleteDBInstanceRequest();
+        request.setDBInstanceIdentifier(identifier);
+        request.setSkipFinalSnapshot(true);
+
+        // Delete the RDS instance
+        DBInstance instance = amazonRDS.deleteDBInstance(request);
+
+        // Information about the RDS instance being deleted
+        String status = instance.getDBInstanceStatus();
+        Endpoint endpoint = instance.getEndpoint();
+        String endpoint_url = "Endpoint URL not available yet.";
+        if (endpoint != null) {
+            endpoint_url = endpoint.toString();
+        }
+
+        logger.info(identifier + "\t" + status);
+        logger.info(endpoint_url);
+
+    }
+
+
+    public void runJdbcTests() throws SQLException, IOException {
+
+        // Getting database properties from db.properties
+        Properties prop = new Properties();
+        InputStream input = AWSRDSService.class.getClassLoader().getResourceAsStream("db.properties");
+        prop.load(input);
+        db_hostname = prop.getProperty("db_hostname");
+        String jdbc_url = "jdbc:postgresql://" + db_hostname + ":5432/" + db_database;
+
+        // Create a connection using the JDBC driver
+        try (Connection conn = DriverManager.getConnection(jdbc_url, db_username, db_password)) {
+
+            // Create the test table if not exists
+            Statement statement = conn.createStatement();
+            String sql = "CREATE TABLE IF NOT EXISTS jdbc_test (id SERIAL PRIMARY KEY, content VARCHAR(80))";
+            statement.executeUpdate(sql);
+
+            // Do some INSERT
+            PreparedStatement preparedStatement = conn.prepareStatement("INSERT INTO jdbc_test (content) VALUES (?)");
+            String content = "" + UUID.randomUUID();
+            preparedStatement.setString(1, content);
+            preparedStatement.executeUpdate();
+            logger.info("INSERT: " + content);
+
+            // Do some SELECT
+            sql = "SELECT  * FROM jdbc_test";
+            ResultSet resultSet = statement.executeQuery(sql);
+            while (resultSet.next()) {
+                String count = resultSet.getString("content");
+                logger.info("Total Records: " + count);
+            }
+        }
+
+
+    }
+
+    public static void main(String[] args) throws IOException, SQLException {
+        AWSRDSService awsrdsService = new AWSRDSService();
+
+        String instanceName = awsrdsService.launchInstance();
+
+        //Add some wait for instance creation.
+
+        awsrdsService.listInstances();
+
+        awsrdsService.runJdbcTests();
+
+        awsrdsService.terminateInstance(instanceName);
+    }
+}

aws/src/main/resources/db.properties

@@ -0,0 +1,4 @@
+db_hostname=<RDS EndPoint>
+db_username=username
+db_password=password
+db_database=mydb

checker-plugin/pom.xml

@@ -41,27 +41,6 @@
 
     <build>
         <plugins>
-            <plugin>
-                <!-- This plugin will set properties values using dependency information -->
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-dependency-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <goals>
-                            <!--
-                            Goal that sets a property pointing to the artifact file for each project dependency.
-                            For each dependency (direct and transitive) a project property will be set which
-                            follows the:
-
-                               groupId:artifactId:type:[classifier]
-
-                            form and contains the path to the resolved artifact. -->
-                            <goal>properties</goal>
-                        </goals>
-                    </execution>
-                </executions>
-            </plugin>
-
             <plugin>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>${maven-compiler-plugin.version}</version>

core-java-8/README.md

@@ -29,3 +29,6 @@
 - [Java 8 Unsigned Arithmetic Support](http://www.baeldung.com/java-unsigned-arithmetic)
 - [Generalized Target-Type Inference in Java](http://www.baeldung.com/java-generalized-target-type-inference)
 - [Overriding System Time for Testing in Java](http://www.baeldung.com/java-override-system-time)
+- [Set the Time Zone of a Date in Java](https://www.baeldung.com/java-set-date-time-zone)
+- [An Overview of Regular Expressions Performance in Java](https://www.baeldung.com/java-regex-performance)
+- [Java Primitives versus Objects](https://www.baeldung.com/java-primitives-vs-objects)

core-java-8/pom.xml

@@ -116,23 +116,6 @@
         </resources>
 
         <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-dependency-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <id>copy-dependencies</id>
-                        <phase>prepare-package</phase>
-                        <goals>
-                            <goal>copy-dependencies</goal>
-                        </goals>
-                        <configuration>
-                            <outputDirectory>${project.build.directory}/libs</outputDirectory>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
-
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>

core-java-9/README.md

@@ -24,3 +24,5 @@
 - [Optional orElse Optional](http://www.baeldung.com/java-optional-or-else-optional)
 - [Java 9 java.lang.Module API](http://www.baeldung.com/java-9-module-api)
 - [Iterate Through a Range of Dates in Java](https://www.baeldung.com/java-iterate-date-range)
+- [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)
+- [Java 9 Platform Logging API](https://www.baeldung.com/java-9-logging-api)

core-java-9/logging.sh

@@ -0,0 +1,15 @@
+# compile logging  module
+# javac --module-path mods -d mods/com.baeldung.logging src/modules/com.baeldung.logging/module-info.java src/modules/com.baeldung.logging/com/baeldung/logging/*.java
+
+# compile logging slf4j module
+javac --module-path mods -d mods/com.baeldung.logging.slf4j src/modules/com.baeldung.logging.slf4j/module-info.java src/modules/com.baeldung.logging.slf4j/com/baeldung/logging/slf4j/*.java
+
+
+# compile logging main app module
+javac --module-path mods -d mods/com.baeldung.logging.app src/modules/com.baeldung.logging.app/module-info.java src/modules/com.baeldung.logging.app/com/baeldung/logging/app/*.java
+
+# run logging main app
+# java --module-path mods -m com.baeldung.logging.app/com.baeldung.logging.app.MainApp
+
+# run looging main app using logback
+java --module-path mods -Dlogback.configurationFile=mods/logback.xml -m com.baeldung.logging.app/com.baeldung.logging.app.MainApp

core-java-9/mods/logback.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
+            <pattern>
+                %d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} -- %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root>
+        <appender-ref ref="STDOUT"/>
+    </root>
+
+</configuration>

core-java-9/src/modules/com.baeldung.logging.app/com/baeldung/logging/app/MainApp.java

@@ -0,0 +1,13 @@
+package com.baeldung.logging.app;
+
+import static java.lang.System.Logger.*;
+
+public class MainApp {
+
+    private static System.Logger LOGGER = System.getLogger("MainApp");
+
+    public static void main(String[] args) {
+        LOGGER.log(Level.ERROR, "error test");
+        LOGGER.log(Level.INFO, "info test");
+    }
+}

core-java-9/src/modules/com.baeldung.logging.app/module-info.java

@@ -0,0 +1,2 @@
+module com.baeldung.logging.app {
+}

core-java-9/src/modules/com.baeldung.logging.slf4j/com/baeldung/logging/slf4j/Slf4jLogger.java

@@ -0,0 +1,99 @@
+package com.baeldung.logging.slf4j;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.ResourceBundle;
+
+public class Slf4jLogger implements System.Logger {
+
+    private final String name;
+    private final Logger logger;
+
+    public Slf4jLogger(String name) {
+        this.name = name;
+        logger = LoggerFactory.getLogger(name);
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public boolean isLoggable(Level level) {
+        switch (level) {
+        case OFF:
+            return false;
+        case TRACE:
+            return logger.isTraceEnabled();
+        case DEBUG:
+            return logger.isDebugEnabled();
+        case INFO:
+            return logger.isInfoEnabled();
+        case WARNING:
+            return logger.isWarnEnabled();
+        case ERROR:
+            return logger.isErrorEnabled();
+        case ALL:
+        default:
+            return true;
+        }
+    }
+
+    @Override
+    public void log(Level level, ResourceBundle bundle, String msg, Throwable thrown) {
+        if (!isLoggable(level)) {
+            return;
+        }
+
+        switch (level) {
+        case TRACE:
+            logger.trace(msg, thrown);
+            break;
+        case DEBUG:
+            logger.debug(msg, thrown);
+            break;
+        case INFO:
+            logger.info(msg, thrown);
+            break;
+        case WARNING:
+            logger.warn(msg, thrown);
+            break;
+        case ERROR:
+            logger.error(msg, thrown);
+            break;
+        case ALL:
+        default:
+            logger.info(msg, thrown);
+        }
+    }
+
+    @Override
+    public void log(Level level, ResourceBundle bundle, String format, Object... params) {
+        if (!isLoggable(level)) {
+            return;
+        }
+
+        switch (level) {
+        case TRACE:
+            logger.trace(format, params);
+            break;
+        case DEBUG:
+            logger.debug(format, params);
+            break;
+        case INFO:
+            logger.info(format, params);
+            break;
+        case WARNING:
+            logger.warn(format, params);
+            break;
+        case ERROR:
+            logger.error(format, params);
+            break;
+        case ALL:
+        default:
+            logger.info(format, params);
+        }
+    }
+}

core-java-9/src/modules/com.baeldung.logging.slf4j/com/baeldung/logging/slf4j/Slf4jLoggerFinder.java

@@ -0,0 +1,8 @@
+package com.baeldung.logging.slf4j;
+
+public class Slf4jLoggerFinder extends System.LoggerFinder {
+    @Override
+    public System.Logger getLogger(String name, Module module) {
+        return new Slf4jLogger(name);
+    }
+}

core-java-9/src/modules/com.baeldung.logging.slf4j/module-info.java

@@ -0,0 +1,6 @@
+module com.baeldung.logging.slf4j {
+    requires org.slf4j;
+    provides java.lang.System.LoggerFinder
+      with com.baeldung.logging.slf4j.Slf4jLoggerFinder;
+    exports com.baeldung.logging.slf4j;
+}

core-java-9/src/modules/com.baeldung.logging/com/baeldung/logging/ConsoleLogger.java

@@ -0,0 +1,27 @@
+package com.baeldung.logging;
+
+import java.text.MessageFormat;
+import java.util.ResourceBundle;
+
+public class ConsoleLogger implements System.Logger {
+
+    @Override
+    public String getName() {
+        return "ConsoleLogger";
+    }
+
+    @Override
+    public boolean isLoggable(Level level) {
+        return true;
+    }
+
+    @Override
+    public void log(Level level, ResourceBundle bundle, String msg, Throwable thrown) {
+        System.out.printf("ConsoleLogger [%s]: %s - %s%n", level, msg, thrown);
+    }
+
+    @Override
+    public void log(Level level, ResourceBundle bundle, String format, Object... params) {
+        System.out.printf("ConsoleLogger [%s]: %s%n", level, MessageFormat.format(format, params));
+    }
+}

core-java-9/src/modules/com.baeldung.logging/com/baeldung/logging/CustomLoggerFinder.java

@@ -0,0 +1,9 @@
+package com.baeldung.logging;
+
+public class CustomLoggerFinder extends System.LoggerFinder {
+
+    @Override
+    public System.Logger getLogger(String name, Module module) {
+        return new ConsoleLogger();
+    }
+}

core-java-9/src/modules/com.baeldung.logging/module-info.java

@@ -0,0 +1,5 @@
+module com.baeldung.logging {
+    provides java.lang.System.LoggerFinder
+      with com.baeldung.logging.CustomLoggerFinder;
+    exports com.baeldung.logging;
+}

core-java-9/src/test/java/com/baeldung/java9/process/ProcessUnderstandingTest.java

@@ -48,7 +48,7 @@ class ProcessUnderstandingTest {
     }
 
     //@Test - windows specific
-    public void givenSubProcess_thenStartSuccessIsAlive() throws IOException {
+    public void givenSubProcess_whenStarted_thenStartSuccessIsAlive() throws IOException {
         ProcessBuilder builder = new ProcessBuilder("notepad.exe");
         assertTrue(builder.start().isAlive());
     }
@@ -75,7 +75,7 @@ class ProcessUnderstandingTest {
     }
 
     //@Test - windows specific
-    public void givenSubProcess_checkAlive() throws IOException, InterruptedException {
+    public void givenSubProcess_whenDestroyed_thenCheckIfAlive() throws IOException, InterruptedException {
         ProcessBuilder builder = new ProcessBuilder("notepad.exe");
         Process process = builder.start();
         Thread.sleep(10000);

core-java-collections/README.md

@@ -43,3 +43,9 @@
 - [An Introduction to Java.util.Hashtable Class](http://www.baeldung.com/java-hash-table)
 - [Copy a List to Another List in Java](http://www.baeldung.com/java-copy-list-to-another)
 - [Finding Max/Min of a List or Collection](http://www.baeldung.com/java-collection-min-max)
+- [Java Null-Safe Streams from Collections](https://www.baeldung.com/java-null-safe-streams-from-collections)
+- [Remove All Occurrences of a Specific Value from a List](https://www.baeldung.com/java-remove-value-from-list)
+- [Thread Safe LIFO Data Structure Implementations](https://www.baeldung.com/java-lifo-thread-safe)
+- [Collections.emptyList() vs. New List Instance](https://www.baeldung.com/java-collections-emptylist-new-list)
+- [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)
+- [](https://www.baeldung.com/java-hashset-arraylist-contains-performance)

core-java-collections/src/main/java/com/baeldung/java/map/MapUtil.java

@@ -0,0 +1,44 @@
+/**
+ * 
+ */
+package com.baeldung.java.map;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.Map.Entry;
+import java.util.stream.Stream;
+
+/**
+ * @author swpraman
+ *
+ */
+public class MapUtil {
+    
+    public static <K, V> Stream<K> keys(Map<K, V> map, V value) {
+        return map.entrySet()
+                .stream()
+                .filter(entry -> value.equals(entry.getValue()))
+                .map(Map.Entry::getKey);
+    }
+    
+    public static <K, V> Set<K> getKeys(Map<K, V> map, V value) {
+        Set<K> keys = new HashSet<>();
+        for (Entry<K, V> entry : map.entrySet()) {
+            if (entry.getValue().equals(value)) {
+                keys.add(entry.getKey());
+            }
+        }
+        return keys;
+    }
+    
+    public static <K, V> K getKey(Map<K, V> map, V value) {
+        for (Entry<K, V> entry : map.entrySet()) {
+            if (entry.getValue().equals(value)) {
+                return entry.getKey();
+            }
+        }
+        return null;
+    }
+
+}

core-java-collections/src/main/java/com/baeldung/performance/ArrayListBenchmark.java

@@ -0,0 +1,77 @@
+package com.baeldung.performance;
+
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+import java.util.*;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@Warmup(iterations = 10)
+public class ArrayListBenchmark {
+
+    @State(Scope.Thread)
+    public static class MyState {
+
+        List<Employee> employeeList = new ArrayList<>();
+        //LinkedList<Employee> employeeList = new LinkedList<>();
+
+        long iterations = 100000;
+
+        Employee employee = new Employee(100L, "Harry");
+
+        int employeeIndex = -1;
+
+        @Setup(Level.Trial)
+        public void setUp() {
+            for (long i = 0; i < iterations; i++) {
+                employeeList.add(new Employee(i, "John"));
+            }
+
+            employeeList.add(employee);
+            employeeIndex = employeeList.indexOf(employee);
+        }
+    }
+
+    @Benchmark
+    public void testAddAt(ArrayListBenchmark.MyState state) {
+        state.employeeList.add((int) (state.iterations), new Employee(state.iterations, "John"));
+    }
+
+    @Benchmark
+    public boolean testContains(ArrayListBenchmark.MyState state) {
+        return state.employeeList.contains(state.employee);
+    }
+
+    @Benchmark
+    public int testIndexOf(ArrayListBenchmark.MyState state) {
+        return state.employeeList.indexOf(state.employee);
+    }
+
+    @Benchmark
+    public Employee testGet(ArrayListBenchmark.MyState state) {
+        return state.employeeList.get(state.employeeIndex);
+    }
+
+    @Benchmark
+    public boolean testRemove(ArrayListBenchmark.MyState state) {
+        return state.employeeList.remove(state.employee);
+    }
+
+//    @Benchmark
+//    public void testAdd(ArrayListBenchmark.MyState state) {
+//        state.employeeList.add(new Employee(state.iterations + 1, "John"));
+//    }
+
+    public static void main(String[] args) throws Exception {
+        Options options = new OptionsBuilder()
+                .include(ArrayListBenchmark.class.getSimpleName()).threads(1)
+                .forks(1).shouldFailOnError(true)
+                .shouldDoGC(true)
+                .jvmArgs("-server").build();
+        new Runner(options).run();
+    }
+}

core-java-collections/src/main/java/com/baeldung/performance/CopyOnWriteBenchmark.java

@@ -0,0 +1,78 @@
+package com.baeldung.performance;
+
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@Warmup(iterations = 10)
+public class CopyOnWriteBenchmark {
+
+    @State(Scope.Thread)
+    public static class MyState {
+
+        CopyOnWriteArrayList<Employee> employeeList = new CopyOnWriteArrayList<>();
+
+        long iterations = 100000;
+
+        Employee employee = new Employee(100L, "Harry");
+
+        int employeeIndex = -1;
+
+        @Setup(Level.Trial)
+        public void setUp() {
+            for (long i = 0; i < iterations; i++) {
+                employeeList.add(new Employee(i, "John"));
+            }
+
+            employeeList.add(employee);
+
+            employeeIndex = employeeList.indexOf(employee);
+        }
+    }
+
+        @Benchmark
+    public void testAdd(CopyOnWriteBenchmark.MyState state) {
+            state.employeeList.add(new Employee(state.iterations + 1, "John"));
+    }
+
+    @Benchmark
+    public void testAddAt(CopyOnWriteBenchmark.MyState state) {
+        state.employeeList.add((int) (state.iterations), new Employee(state.iterations, "John"));
+    }
+
+    @Benchmark
+    public boolean testContains(CopyOnWriteBenchmark.MyState state) {
+        return state.employeeList.contains(state.employee);
+    }
+
+    @Benchmark
+    public int testIndexOf(CopyOnWriteBenchmark.MyState state) {
+        return state.employeeList.indexOf(state.employee);
+    }
+
+    @Benchmark
+    public Employee testGet(CopyOnWriteBenchmark.MyState state) {
+        return state.employeeList.get(state.employeeIndex);
+    }
+
+    @Benchmark
+    public boolean testRemove(CopyOnWriteBenchmark.MyState state) {
+        return state.employeeList.remove(state.employee);
+    }
+
+
+    public static void main(String[] args) throws Exception {
+        Options options = new OptionsBuilder()
+                .include(CopyOnWriteBenchmark.class.getSimpleName()).threads(1)
+                .forks(1).shouldFailOnError(true)
+                .shouldDoGC(true)
+                .jvmArgs("-server").build();
+        new Runner(options).run();
+    }
+}

core-java-collections/src/main/java/com/baeldung/performance/Employee.java

@@ -10,6 +10,22 @@ public class Employee {
         this.id = id;
     }
 
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;

core-java-collections/src/main/java/com/baeldung/performance/HashMapBenchmark.java

@@ -0,0 +1,73 @@
+package com.baeldung.performance;
+
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+import java.util.*;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@Warmup(iterations = 10)
+public class HashMapBenchmark {
+
+    @State(Scope.Thread)
+    public static class MyState {
+
+        Map<Long, Employee> employeeMap = new HashMap<>();
+        //LinkedHashMap<Long, Employee> employeeMap = new LinkedHashMap<>();
+        //IdentityHashMap<Long, Employee> employeeMap = new IdentityHashMap<>();
+        //WeakHashMap<Long, Employee> employeeMap = new WeakHashMap<>();
+        //ConcurrentHashMap<Long, Employee> employeeMap = new ConcurrentHashMap<>();
+        //ConcurrentSkipListMap<Long, Employee> employeeMap = new ConcurrentSkipListMap <>();
+
+        // TreeMap
+
+        long iterations = 100000;
+
+        Employee employee = new Employee(100L, "Harry");
+
+        int employeeIndex = -1;
+
+        @Setup(Level.Trial)
+        public void setUp() {
+            for (long i = 0; i < iterations; i++) {
+                employeeMap.put(i, new Employee(i, "John"));
+            }
+
+            //employeeMap.put(iterations, employee);
+        }
+    }
+
+    @Benchmark
+    public Employee testGet(HashMapBenchmark.MyState state) {
+        return state.employeeMap.get(state.iterations);
+    }
+
+    @Benchmark
+    public Employee testRemove(HashMapBenchmark.MyState state) {
+        return state.employeeMap.remove(state.iterations);
+    }
+
+    @Benchmark
+    public Employee testPut(HashMapBenchmark.MyState state) {
+        return state.employeeMap.put(state.employee.getId(), state.employee);
+    }
+
+    @Benchmark
+    public Boolean testContainsKey(HashMapBenchmark.MyState state) {
+        return state.employeeMap.containsKey(state.employee.getId());
+    }
+
+
+    public static void main(String[] args) throws Exception {
+        Options options = new OptionsBuilder()
+                .include(HashMapBenchmark.class.getSimpleName()).threads(1)
+                .forks(1).shouldFailOnError(true)
+                .shouldDoGC(true)
+                .jvmArgs("-server").build();
+        new Runner(options).run();
+    }
+}

core-java-collections/src/main/java/com/baeldung/performance/SetBenchMark.java

@@ -0,0 +1,66 @@
+package com.baeldung.performance;
+
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.concurrent.ConcurrentSkipListSet;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@Warmup(iterations = 10)
+public class SetBenchMark {
+
+    @State(Scope.Thread)
+    public static class MyState {
+
+        //Set<Employee> employeeSet = new HashSet<>();
+        LinkedHashSet<Employee> employeeSet = new LinkedHashSet<>();
+        //ConcurrentSkipListSet<Employee> employeeSet = new ConcurrentSkipListSet <>();
+
+        // TreeSet 
+
+        long iterations = 1000;
+        Employee employee = new Employee(100L, "Harry");
+
+        @Setup(Level.Trial)
+        public void setUp() {
+            for (long i = 0; i < iterations; i++) {
+                employeeSet.add(new Employee(i, "John"));
+            }
+
+            //employeeSet.add(employee);
+        }
+    }
+
+    @Benchmark
+    public boolean testAdd(SetBenchMark.MyState state) {
+        return state.employeeSet.add(state.employee);
+    }
+
+    @Benchmark
+    public Boolean testContains(SetBenchMark.MyState state) {
+        return state.employeeSet.contains(state.employee);
+    }
+
+    @Benchmark
+    public boolean testRemove(SetBenchMark.MyState state) {
+        return state.employeeSet.remove(state.employee);
+    }
+
+
+    public static void main(String[] args) throws Exception {
+        Options options = new OptionsBuilder()
+                .include(SetBenchMark.class.getSimpleName()).threads(1)
+                .forks(1).shouldFailOnError(true)
+                .shouldDoGC(true)
+                .jvmArgs("-server").build();
+        new Runner(options).run();
+    }
+}

core-java-collections/src/test/java/com/baeldung/collection/ClearVsRemoveAllUnitTest.java

@@ -0,0 +1,40 @@
+package com.baeldung.collection;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Unit tests demonstrating differences between ArrayList#clear() and ArrayList#removeAll()
+ */
+class ClearVsRemoveAllUnitTest {
+
+    /*
+     * Tests
+     */
+    @Test
+    void givenArrayListWithElements_whenClear_thenListBecomesEmpty() {
+        Collection<Integer> collection = new ArrayList<>(Arrays.asList(1, 2, 3, 4, 5));
+
+        collection.clear();
+
+        assertTrue(collection.isEmpty());
+    }
+
+    @Test
+    void givenTwoArrayListsWithCommonElements_whenRemoveAll_thenFirstListMissElementsFromSecondList() {
+        Collection<Integer> firstCollection = new ArrayList<>(Arrays.asList(1, 2, 3, 4, 5));
+        Collection<Integer> secondCollection = new ArrayList<>(Arrays.asList(3, 4, 5, 6, 7));
+
+        firstCollection.removeAll(secondCollection);
+
+        assertEquals(Arrays.asList(1, 2), firstCollection);
+        assertEquals(Arrays.asList(3, 4, 5, 6, 7), secondCollection);
+    }
+
+}

core-java-collections/src/test/java/com/baeldung/java/map/MapUtilUnitTest.java

@@ -0,0 +1,104 @@
+/**
+ * 
+ */
+package com.baeldung.java.map;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.apache.commons.collections4.BidiMap;
+import org.apache.commons.collections4.bidimap.DualHashBidiMap;
+import org.junit.Test;
+
+import com.google.common.collect.HashBiMap;
+
+/**
+ * @author swpraman
+ *
+ */
+public class MapUtilUnitTest {
+    
+    
+    @Test
+    public void whenUsingImperativeWayForSingleKey_shouldReturnSingleKey() {
+        Map<String, String> capitalCountryMap = new HashMap<>();
+        capitalCountryMap.put("Tokyo", "Japan");
+        capitalCountryMap.put("New Delhi", "India");
+        assertEquals("New Delhi", MapUtil.getKey(capitalCountryMap, "India"));
+    }
+    
+    @Test
+    public void whenUsingImperativeWayForAllKeys_shouldReturnAllKeys() {
+        Map<String, String> capitalCountryMap = new HashMap<>();
+        capitalCountryMap.put("Tokyo", "Japan");
+        capitalCountryMap.put("Berlin", "Germany");
+        capitalCountryMap.put("Cape Town", "South Africa");
+        capitalCountryMap.put("Pretoria", "South Africa");
+        capitalCountryMap.put("Bloemfontein", "South Africa");
+
+        assertEquals(new HashSet<String>(Arrays.asList(
+                new String[] {"Cape Town", "Pretoria", "Bloemfontein"})), 
+                MapUtil.getKeys(capitalCountryMap, "South Africa"));
+    }
+    
+    @Test
+    public void whenUsingFunctionalWayForSingleKey_shouldReturnSingleKey() {
+        Map<String, String> capitalCountryMap = new HashMap<>();
+        capitalCountryMap.put("Tokyo", "Japan");
+        capitalCountryMap.put("Berlin", "Germany");
+        assertEquals("Berlin", MapUtil.keys(capitalCountryMap, "Germany").findFirst().get());
+    }
+    
+    @Test
+    public void whenUsingFunctionalWayForAllKeys_shouldReturnAllKeys() {
+        Map<String, String> capitalCountryMap = new HashMap<>();
+        capitalCountryMap.put("Tokyo", "Japan");
+        capitalCountryMap.put("Berlin", "Germany");
+        capitalCountryMap.put("Cape Town", "South Africa");
+        capitalCountryMap.put("Pretoria", "South Africa");
+        capitalCountryMap.put("Bloemfontein", "South Africa");
+        assertEquals(new HashSet<String>(Arrays.asList(
+                new String[] {"Cape Town", "Pretoria", "Bloemfontein"})), 
+                MapUtil.keys(capitalCountryMap, "South Africa").collect(Collectors.toSet()));
+    }
+    
+    @Test
+    public void whenUsingBidiMap_shouldReturnKey() {
+        BidiMap<String, String> capitalCountryMap = new DualHashBidiMap<String, String>();
+        capitalCountryMap.put("Berlin", "Germany");
+        capitalCountryMap.put("Cape Town", "South Africa");
+        assertEquals("Berlin", capitalCountryMap.getKey("Germany"));
+    }
+    
+    @Test
+    public void whenUsingBidiMapAddDuplicateValue_shouldRemoveOldEntry() {
+        BidiMap<String, String> capitalCountryMap = new DualHashBidiMap<String, String>();
+        capitalCountryMap.put("Berlin", "Germany");
+        capitalCountryMap.put("Cape Town", "South Africa");
+        capitalCountryMap.put("Pretoria", "South Africa");
+        assertEquals("Pretoria", capitalCountryMap.getKey("South Africa"));
+    }
+    
+    @Test
+    public void whenUsingBiMap_shouldReturnKey() {
+        HashBiMap<String, String> capitalCountryMap = HashBiMap.create();
+        capitalCountryMap.put("Berlin", "Germany");
+        capitalCountryMap.put("Cape Town", "South Africa");
+        assertEquals("Berlin", capitalCountryMap.inverse().get("Germany"));
+    }
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingBiMapAddDuplicateValue_shouldThrowException() {
+        HashBiMap<String, String> capitalCountryMap = HashBiMap.create();
+        capitalCountryMap.put("Berlin", "Germany");
+        capitalCountryMap.put("Cape Town", "South Africa");
+        capitalCountryMap.put("Pretoria", "South Africa");
+        assertEquals("Berlin", capitalCountryMap.inverse().get("Germany"));
+    }
+
+}

core-java-concurrency-collections/pom.xml

@@ -57,26 +57,6 @@
                 <filtering>true</filtering>
             </resource>
         </resources>
-
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-dependency-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <id>copy-dependencies</id>
-                        <phase>prepare-package</phase>
-                        <goals>
-                            <goal>copy-dependencies</goal>
-                        </goals>
-                        <configuration>
-                            <outputDirectory>${project.build.directory}/libs</outputDirectory>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
-            
-        </plugins>
     </build>
 
     <properties>

core-java-concurrency/pom.xml

@@ -57,26 +57,6 @@
                 <filtering>true</filtering>
             </resource>
         </resources>
-
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-dependency-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <id>copy-dependencies</id>
-                        <phase>prepare-package</phase>
-                        <goals>
-                            <goal>copy-dependencies</goal>
-                        </goals>
-                        <configuration>
-                            <outputDirectory>${project.build.directory}/libs</outputDirectory>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
-            
-        </plugins>
     </build>
 
     <properties>

core-java-concurrency/src/main/java/com/baeldung/concurrent/yield/ThreadYield.java

@@ -0,0 +1,17 @@
+package com.baeldung.concurrent.yield;
+
+public class ThreadYield {
+    public static void main(String[] args) {
+        Runnable r = () -> {
+            int counter = 0;
+            while (counter < 2) {
+                System.out.println(Thread.currentThread()
+                    .getName());
+                counter++;
+                Thread.yield();
+            }
+        };
+        new Thread(r).start();
+        new Thread(r).start();
+    }
+}

core-java-io/README.md

@@ -30,3 +30,4 @@
 - [Download a File From an URL in Java](http://www.baeldung.com/java-download-file)
 - [Create a Symbolic Link with Java](http://www.baeldung.com/java-symlink)
 - [Quick Use of FilenameFilter](http://www.baeldung.com/java-filename-filter)
+- [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)

core-java-io/src/test/java/com/baeldung/file/FileOperationsManualTest.java

@@ -1,6 +1,7 @@
 package com.baeldung.file;
 
 import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.IOUtils;
 import org.hamcrest.CoreMatchers;
 import org.hamcrest.Matchers;
 import org.junit.Test;
@@ -120,4 +121,14 @@ public class FileOperationsManualTest {
 
         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-persistence/README.md

@@ -6,3 +6,4 @@
 - [Introduction to JDBC](http://www.baeldung.com/java-jdbc)
 - [Batch Processing in JDBC](http://www.baeldung.com/jdbc-batch-processing)
 - [Introduction to the JDBC RowSet Interface in Java](http://www.baeldung.com/java-jdbc-rowset)
+- [A Simple Guide to Connection Pooling in Java](https://www.baeldung.com/java-connection-pooling)

core-java-sun/pom.xml

@@ -166,22 +166,6 @@
             </resource>
         </resources>
         <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-dependency-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <id>copy-dependencies</id>
-                        <phase>prepare-package</phase>
-                        <goals>
-                            <goal>copy-dependencies</goal>
-                        </goals>
-                        <configuration>
-                            <outputDirectory>${project.build.directory}/libs</outputDirectory>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-jar-plugin</artifactId>

core-java/README.md

@@ -145,3 +145,9 @@
 - [Common Java Exceptions](http://www.baeldung.com/java-common-exceptions)
 - [Java Constructors vs Static Factory Methods](https://www.baeldung.com/java-constructors-vs-static-factory-methods)
 - [Differences Between Final, Finally and Finalize in Java](https://www.baeldung.com/java-final-finally-finalize)
+- [Static and Dynamic Binding in Java](https://www.baeldung.com/java-static-dynamic-binding)
+- [Java List Initialization in One Line](https://www.baeldung.com/java-init-list-one-line)
+- [Difference Between Throw and Throws in Java](https://www.baeldung.com/java-throw-throws)
+- [ClassCastException: Arrays$ArrayList cannot be cast to ArrayList](https://www.baeldung.com/java-classcastexception-arrays-arraylist)
+- [Throw Exception in Optional in Java 8](https://www.baeldung.com/java-optional-throw-exception)
+- [Add a Character to a String at a Given Position](https://www.baeldung.com/java-add-character-to-string)

core-java/src/main/java/com/baeldung/doubles/SplitFloatingPointNumbers.java

@@ -0,0 +1,40 @@
+package com.baeldung.doubles;
+
+import java.math.BigDecimal;
+
+public class SplitFloatingPointNumbers {
+
+    public static void main(String[] args) {
+        
+        double doubleNumber = 24.04;
+        splitUsingFloatingTypes(doubleNumber); 
+        splitUsingString(doubleNumber);
+        splitUsingBigDecimal(doubleNumber);
+    }
+
+    private static void splitUsingFloatingTypes(double doubleNumber) {
+        System.out.println("Using Floating Point Arithmetics:");
+        int intPart = (int) doubleNumber;
+        System.out.println("Double Number: "+doubleNumber);
+        System.out.println("Integer Part: "+ intPart);
+        System.out.println("Decimal Part: "+ (doubleNumber - intPart));
+    }
+
+    private static void splitUsingString(double doubleNumber) {
+        System.out.println("Using String Operations:");
+        String doubleAsString = String.valueOf(doubleNumber);
+        int indexOfDecimal = doubleAsString.indexOf(".");
+        System.out.println("Double Number: "+doubleNumber);
+        System.out.println("Integer Part: "+ doubleAsString.substring(0, indexOfDecimal));
+        System.out.println("Decimal Part: "+ doubleAsString.substring(indexOfDecimal));
+    }
+
+    private static void splitUsingBigDecimal(double doubleNumber) {
+        System.out.println("Using BigDecimal Operations:");
+        BigDecimal bigDecimal = new BigDecimal(String.valueOf(doubleNumber));
+        int intValue = bigDecimal.intValue();
+        System.out.println("Double Number: "+bigDecimal.toPlainString());
+        System.out.println("Integer Part: "+intValue);
+        System.out.println("Decimal Part: "+bigDecimal.subtract(new BigDecimal(intValue)).toPlainString());
+    }
+}

core-java/src/main/java/com/baeldung/heapdump/HeapDump.java

@@ -0,0 +1,25 @@
+package com.baeldung.heapdump;
+
+import com.sun.management.HotSpotDiagnosticMXBean;
+
+import javax.management.MBeanServer;
+
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.nio.file.Paths;
+
+public class HeapDump {
+
+    public static void dumpHeap(String filePath, boolean live) throws IOException {
+        MBeanServer server = ManagementFactory.getPlatformMBeanServer();
+        HotSpotDiagnosticMXBean mxBean = ManagementFactory.newPlatformMXBeanProxy(
+          server, "com.sun.management:type=HotSpotDiagnostic", HotSpotDiagnosticMXBean.class);
+        mxBean.dumpHeap(filePath, live);
+    }
+
+    public static void main(String[] args) throws IOException {
+        String file = Paths.get("dump.hprof").toFile().getPath();
+
+        dumpHeap(file, true);
+    }
+}

core-java/src/main/java/com/baeldung/passwordhashing/PBKDF2Hasher.java

@@ -0,0 +1,149 @@
+package com.baeldung.passwordhashing;
+
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.KeySpec;
+import java.util.Arrays;
+import java.util.Base64;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+
+/**
+ * Hash passwords for storage, and test passwords against password tokens.
+ *
+ * Instances of this class can be used concurrently by multiple threads.
+ *
+ * @author erickson
+ * @see <a href="http://stackoverflow.com/a/2861125/3474">StackOverflow</a>
+ */
+public final class PBKDF2Hasher
+{
+
+  /**
+   * Each token produced by this class uses this identifier as a prefix.
+   */
+  public static final String ID = "$31$";
+
+  /**
+   * The minimum recommended cost, used by default
+   */
+  public static final int DEFAULT_COST = 16;
+
+  private static final String ALGORITHM = "PBKDF2WithHmacSHA1";
+
+  private static final int SIZE = 128;
+
+  private static final Pattern layout = Pattern.compile("\\$31\\$(\\d\\d?)\\$(.{43})");
+
+  private final SecureRandom random;
+
+  private final int cost;
+
+  public PBKDF2Hasher()
+  {
+    this(DEFAULT_COST);
+  }
+
+  /**
+   * Create a password manager with a specified cost
+   *
+   * @param cost the exponential computational cost of hashing a password, 0 to 30
+   */
+  public PBKDF2Hasher(int cost)
+  {
+    iterations(cost); /* Validate cost */
+    this.cost = cost;
+    this.random = new SecureRandom();
+  }
+
+  private static int iterations(int cost)
+  {
+    if ((cost < 0) || (cost > 30))
+      throw new IllegalArgumentException("cost: " + cost);
+    return 1 << cost;
+  }
+
+  /**
+   * Hash a password for storage.
+   *
+   * @return a secure authentication token to be stored for later authentication
+   */
+  public String hash(char[] password)
+  {
+    byte[] salt = new byte[SIZE / 8];
+    random.nextBytes(salt);
+    byte[] dk = pbkdf2(password, salt, 1 << cost);
+    byte[] hash = new byte[salt.length + dk.length];
+    System.arraycopy(salt, 0, hash, 0, salt.length);
+    System.arraycopy(dk, 0, hash, salt.length, dk.length);
+    Base64.Encoder enc = Base64.getUrlEncoder().withoutPadding();
+    return ID + cost + '$' + enc.encodeToString(hash);
+  }
+
+  /**
+   * Authenticate with a password and a stored password token.
+   *
+   * @return true if the password and token match
+   */
+  public boolean checkPassword(char[] password, String token)
+  {
+    Matcher m = layout.matcher(token);
+    if (!m.matches())
+      throw new IllegalArgumentException("Invalid token format");
+    int iterations = iterations(Integer.parseInt(m.group(1)));
+    byte[] hash = Base64.getUrlDecoder().decode(m.group(2));
+    byte[] salt = Arrays.copyOfRange(hash, 0, SIZE / 8);
+    byte[] check = pbkdf2(password, salt, iterations);
+    int zero = 0;
+    for (int idx = 0; idx < check.length; ++idx)
+      zero |= hash[salt.length + idx] ^ check[idx];
+    return zero == 0;
+  }
+
+  private static byte[] pbkdf2(char[] password, byte[] salt, int iterations)
+  {
+    KeySpec spec = new PBEKeySpec(password, salt, iterations, SIZE);
+    try {
+      SecretKeyFactory f = SecretKeyFactory.getInstance(ALGORITHM);
+      return f.generateSecret(spec).getEncoded();
+    }
+    catch (NoSuchAlgorithmException ex) {
+      throw new IllegalStateException("Missing algorithm: " + ALGORITHM, ex);
+    }
+    catch (InvalidKeySpecException ex) {
+      throw new IllegalStateException("Invalid SecretKeyFactory", ex);
+    }
+  }
+
+  /**
+   * Hash a password in an immutable {@code String}.
+   *
+   * <p>Passwords should be stored in a {@code char[]} so that it can be filled
+   * with zeros after use instead of lingering on the heap and elsewhere.
+   *
+   * @deprecated Use {@link #hash(char[])} instead
+   */
+  @Deprecated
+  public String hash(String password)
+  {
+    return hash(password.toCharArray());
+  }
+
+  /**
+   * Authenticate with a password in an immutable {@code String} and a stored
+   * password token.
+   *
+   * @deprecated Use {@link #checkPassword(char[],String)} instead.
+   * @see #hash(String)
+   */
+  @Deprecated
+  public boolean checkPassword(String password, String token)
+  {
+    return checkPassword(password.toCharArray(), token);
+  }
+
+}

core-java/src/main/java/com/baeldung/passwordhashing/SHA512Hasher.java

@@ -0,0 +1,35 @@
+package com.baeldung.passwordhashing;
+
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+
+/** A really simple SHA_512 Encryption example.
+ *
+ */
+public class SHA512Hasher {
+
+  public String hash(String passwordToHash, byte[] salt){
+    String generatedPassword = null;
+    try {
+      MessageDigest md = MessageDigest.getInstance("SHA-512");
+      md.update(salt);
+      byte[] bytes = md.digest(passwordToHash.getBytes(StandardCharsets.UTF_8));
+      StringBuilder sb = new StringBuilder();
+      for(int i=0; i< bytes.length ;i++){
+        sb.append(Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1));
+      }
+      generatedPassword = sb.toString();
+    }
+    catch (NoSuchAlgorithmException e){
+      e.printStackTrace();
+    }
+    return generatedPassword;
+  }
+
+  public boolean checkPassword(String hash, String attempt, byte[] salt){
+    String generatedHash = hash(attempt, salt);
+    return hash.equals(generatedHash);
+  }
+}

core-java/src/main/java/com/baeldung/passwordhashing/SimplePBKDF2Hasher.java

@@ -0,0 +1,18 @@
+package com.baeldung.passwordhashing;
+
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+import java.security.spec.KeySpec;
+
+/** A really simple SimplePBKDF2 Encryption example.
+ *
+ */
+public class SimplePBKDF2Hasher {
+
+  public static String hashSimple(String password, byte[] salt) throws Exception{
+    KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, 65536, 128);
+    SecretKeyFactory f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
+    byte[] hash = f.generateSecret(spec).getEncoded();
+    return String.valueOf(hash);
+  }
+}

core-java/src/main/java/com/baeldung/zoneddatetime/OffsetDateTimeExample.java

@@ -0,0 +1,13 @@
+package com.baeldung.zoneddatetime;
+
+import java.time.OffsetDateTime;
+import java.time.ZoneOffset;
+
+public class OffsetDateTimeExample {
+
+    public OffsetDateTime getCurrentTimeByZoneOffset(String offset) {
+        ZoneOffset zoneOffSet= ZoneOffset.of(offset);
+        OffsetDateTime date = OffsetDateTime.now(zoneOffSet);
+        return date;
+    }
+}

core-java/src/main/java/com/baeldung/zoneddatetime/OffsetTimeExample.java

@@ -0,0 +1,13 @@
+package com.baeldung.zoneddatetime;
+
+import java.time.OffsetTime;
+import java.time.ZoneOffset;
+
+public class OffsetTimeExample {
+
+    public OffsetTime getCurrentTimeByZoneOffset(String offset) {
+        ZoneOffset zoneOffSet = ZoneOffset.of(offset);
+        OffsetTime time = OffsetTime.now(zoneOffSet);
+        return time;
+    }
+}

core-java/src/main/java/com/baeldung/zoneddatetime/ZoneDateTimeExample.java

@@ -0,0 +1,21 @@
+package com.baeldung.zoneddatetime;
+
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+
+public class ZoneDateTimeExample {
+
+    public ZonedDateTime getCurrentTimeByZoneId(String region) {
+        ZoneId zone = ZoneId.of(region);
+        ZonedDateTime date = ZonedDateTime.now(zone);
+        return date;
+    }
+
+    public ZonedDateTime convertZonedDateTime(ZonedDateTime sourceDate, String destZone) {
+
+        ZoneId destZoneId = ZoneId.of(destZone);
+        ZonedDateTime destDate = sourceDate.withZoneSameInstant(destZoneId);
+
+        return destDate;
+    }
+}

core-java/src/test/java/com/baeldung/passwordhashing/PBKDF2HasherUnitTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.passwordhashing;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+
+public class PBKDF2HasherUnitTest {
+
+  private PBKDF2Hasher mPBKDF2Hasher;
+
+  @Before
+  public void setUp() throws Exception {
+    mPBKDF2Hasher = new PBKDF2Hasher();
+  }
+
+  @Test
+  public void givenCorrectMessageAndHash_whenAuthenticated_checkAuthenticationSucceeds() throws Exception {
+    String message1 = "password123";
+
+    String hash1 = mPBKDF2Hasher.hash(message1.toCharArray());
+
+    assertTrue(mPBKDF2Hasher.checkPassword(message1.toCharArray(), hash1));
+
+  }
+
+  @Test
+  public void givenWrongMessage_whenAuthenticated_checkAuthenticationFails() throws Exception {
+    String message1 = "password123";
+
+    String hash1 = mPBKDF2Hasher.hash(message1.toCharArray());
+
+    String wrongPasswordAttempt = "IamWrong";
+
+    assertFalse(mPBKDF2Hasher.checkPassword(wrongPasswordAttempt.toCharArray(), hash1));
+
+  }
+
+
+}

core-java/src/test/java/com/baeldung/passwordhashing/SHA512HasherUnitTest.java

@@ -0,0 +1,70 @@
+package com.baeldung.passwordhashing;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.security.SecureRandom;
+
+import static org.junit.Assert.*;
+
+/**
+ * Created by PhysicsSam on 06-Sep-18.
+ */
+public class SHA512HasherUnitTest {
+
+  private SHA512Hasher hasher;
+  private SecureRandom secureRandom;
+
+  @Before
+  public void setUp() throws Exception {
+    hasher = new SHA512Hasher();
+    secureRandom = new SecureRandom();
+  }
+
+  @Test
+  public void givenSamePasswordAndSalt_whenHashed_checkResultingHashesAreEqual() throws Exception {
+
+    byte[] salt = new byte[16];
+    secureRandom.nextBytes(salt);
+
+    String hash1 = hasher.hash("password", salt);
+    String hash2 = hasher.hash("password", salt);
+
+    assertEquals(hash1, hash2);
+
+  }
+
+  @Test
+  public void givenSamePasswordAndDifferentSalt_whenHashed_checkResultingHashesNotEqual() throws Exception {
+
+    byte[] salt = new byte[16];
+    secureRandom.nextBytes(salt);
+    String hash1 = hasher.hash("password", salt);
+    //generate a second salt
+    byte[] secondSalt = new byte[16];
+    String hash2 = hasher.hash("password", secondSalt);
+
+    assertNotEquals(hash1, hash2);
+
+  }
+
+  @Test
+  public void givenPredefinedHash_whenCorrectAttemptGiven_checkAuthenticationSucceeds() throws Exception {
+    byte[] salt = new byte[16];
+    secureRandom.nextBytes(salt);
+
+    String originalHash = hasher.hash("password123", salt);
+
+    assertTrue(hasher.checkPassword(originalHash, "password123", salt));
+  }
+
+  @Test
+  public void givenPredefinedHash_whenIncorrectAttemptGiven_checkAuthenticationFails() throws Exception {
+    byte[] salt = new byte[16];
+    secureRandom.nextBytes(salt);
+
+    String originalHash = hasher.hash("password123", salt);
+
+    assertFalse(hasher.checkPassword(originalHash, "password124", salt));
+  }
+}

core-java/src/test/java/com/baeldung/removingdecimals/RemovingDecimalsManualTest.java

@@ -0,0 +1,100 @@
+package com.baeldung.removingdecimals;
+
+import org.junit.Test;
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+import java.text.DecimalFormat;
+import java.text.NumberFormat;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * This benchmark compares some of the approaches to formatting a floating-point
+ * value into a {@link String} while removing the decimal part.
+ *
+ * To run, simply run the {@link RemovingDecimalsManualTest#runBenchmarks()} test
+ * at the end of this class.
+ *
+ * The benchmark takes about 15 minutes to run. Since it is using {@link Mode#Throughput},
+ * higher numbers mean better performance.
+ */
+@BenchmarkMode(Mode.Throughput)
+@Warmup(iterations = 5)
+@Measurement(iterations = 20)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@State(Scope.Benchmark)
+public class RemovingDecimalsManualTest {
+    @Param(value = {"345.56", "345345345.56", "345345345345345345.56"}) double doubleValue;
+
+    NumberFormat nf;
+    DecimalFormat df;
+
+    @Setup
+    public void readyFormatters() {
+        nf = NumberFormat.getInstance();
+        nf.setMaximumFractionDigits(0);
+        df = new DecimalFormat("#,###");
+    }
+
+    @Benchmark
+    public String whenCastToInt_thenValueIsTruncated() {
+        return String.valueOf((int) doubleValue);
+    }
+
+    @Benchmark
+    public String whenUsingStringFormat_thenValueIsRounded() {
+        return String.format("%.0f", doubleValue);
+    }
+
+    @Benchmark
+    public String whenUsingNumberFormat_thenValueIsRounded() {
+        nf.setRoundingMode(RoundingMode.HALF_UP);
+        return nf.format(doubleValue);
+    }
+
+    @Benchmark
+    public String whenUsingNumberFormatWithFloor_thenValueIsTruncated() {
+        nf.setRoundingMode(RoundingMode.FLOOR);
+        return nf.format(doubleValue);
+    }
+
+    @Benchmark
+    public String whenUsingDecimalFormat_thenValueIsRounded() {
+        df.setRoundingMode(RoundingMode.HALF_UP);
+        return df.format(doubleValue);
+    }
+
+    @Benchmark
+    public String whenUsingDecimalFormatWithFloor_thenValueIsTruncated() {
+        df.setRoundingMode(RoundingMode.FLOOR);
+        return df.format(doubleValue);
+    }
+
+    @Benchmark
+    public String whenUsingBigDecimalDoubleValue_thenValueIsTruncated() {
+        BigDecimal big = new BigDecimal(doubleValue);
+        big = big.setScale(0, RoundingMode.FLOOR);
+        return big.toString();
+    }
+
+    @Benchmark
+    public String whenUsingBigDecimalDoubleValueWithHalfUp_thenValueIsRounded() {
+        BigDecimal big = new BigDecimal(doubleValue);
+        big = big.setScale(0, RoundingMode.HALF_UP);
+        return big.toString();
+    }
+
+    @Test
+    public void runBenchmarks() throws Exception {
+        Options options = new OptionsBuilder()
+                .include(this.getClass().getSimpleName()).threads(1)
+                .forks(1).shouldFailOnError(true).shouldDoGC(true)
+                .jvmArgs("-server").build();
+
+        new Runner(options).run();
+    }
+}

core-java/src/test/java/com/baeldung/removingdecimals/RemovingDecimalsUnitTest.java

@@ -0,0 +1,95 @@
+package com.baeldung.removingdecimals;
+
+import org.junit.Test;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+import java.text.DecimalFormat;
+import java.text.NumberFormat;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+
+/**
+ * Tests that demonstrate some different approaches for formatting a
+ * floating-point value into a {@link String} while removing the decimal part.
+ */
+public class RemovingDecimalsUnitTest {
+    private final double doubleValue = 345.56;
+
+    @Test
+    public void whenCastToInt_thenValueIsTruncated() {
+        String truncated = String.valueOf((int) doubleValue);
+        assertEquals("345", truncated);
+    }
+
+    @Test
+    public void givenALargeDouble_whenCastToInt_thenValueIsNotTruncated() {
+        double outOfIntRange = 6_000_000_000.56;
+        String truncationAttempt = String.valueOf((int) outOfIntRange);
+        assertNotEquals("6000000000", truncationAttempt);
+    }
+
+    @Test
+    public void whenUsingStringFormat_thenValueIsRounded() {
+        String rounded = String.format("%.0f", doubleValue);
+        assertEquals("346", rounded);
+    }
+
+    @Test
+    public void givenALargeDouble_whenUsingStringFormat_thenValueIsStillRounded() {
+        double outOfIntRange = 6_000_000_000.56;
+        String rounded = String.format("%.0f", outOfIntRange);
+        assertEquals("6000000001", rounded);
+    }
+
+    @Test
+    public void whenUsingNumberFormat_thenValueIsRounded() {
+        NumberFormat nf = NumberFormat.getInstance();
+        nf.setMaximumFractionDigits(0);
+        nf.setRoundingMode(RoundingMode.HALF_UP);
+        String rounded = nf.format(doubleValue);
+        assertEquals("346", rounded);
+    }
+
+    @Test
+    public void whenUsingNumberFormatWithFloor_thenValueIsTruncated() {
+        NumberFormat nf = NumberFormat.getInstance();
+        nf.setMaximumFractionDigits(0);
+        nf.setRoundingMode(RoundingMode.FLOOR);
+        String truncated = nf.format(doubleValue);
+        assertEquals("345", truncated);
+    }
+
+    @Test
+    public void whenUsingDecimalFormat_thenValueIsRounded() {
+        DecimalFormat df = new DecimalFormat("#,###");
+        df.setRoundingMode(RoundingMode.HALF_UP);
+        String rounded = df.format(doubleValue);
+        assertEquals("346", rounded);
+    }
+
+    @Test
+    public void whenUsingDecimalFormatWithFloor_thenValueIsTruncated() {
+        DecimalFormat df = new DecimalFormat("#,###");
+        df.setRoundingMode(RoundingMode.FLOOR);
+        String truncated = df.format(doubleValue);
+        assertEquals("345", truncated);
+    }
+
+    @Test
+    public void whenUsingBigDecimalDoubleValue_thenValueIsTruncated() {
+        BigDecimal big = new BigDecimal(doubleValue);
+        big = big.setScale(0, RoundingMode.FLOOR);
+        String truncated = big.toString();
+        assertEquals("345", truncated);
+    }
+
+    @Test
+    public void whenUsingBigDecimalDoubleValueWithHalfUp_thenValueIsRounded() {
+        BigDecimal big = new BigDecimal(doubleValue);
+        big = big.setScale(0, RoundingMode.HALF_UP);
+        String truncated = big.toString();
+        assertEquals("346", truncated);
+    }
+}

core-java/src/test/java/com/baeldung/zoneddatetime/OffsetDateTimeExampleUnitTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.zoneddatetime;
+
+import static org.junit.Assert.assertTrue;
+
+import java.time.OffsetDateTime;
+import java.time.ZoneOffset;
+
+import org.junit.Test;
+
+public class OffsetDateTimeExampleUnitTest {
+
+    OffsetDateTimeExample offsetDateTimeExample = new OffsetDateTimeExample();
+
+    @Test
+    public void givenZoneOffset_whenGetCurrentTime_thenResultHasZone() {
+        String offset = "+02:00";
+        OffsetDateTime time = offsetDateTimeExample.getCurrentTimeByZoneOffset(offset);
+
+        assertTrue(time.getOffset()
+            .equals(ZoneOffset.of(offset)));
+    }
+}

core-java/src/test/java/com/baeldung/zoneddatetime/OffsetTimeExampleUnitTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.zoneddatetime;
+
+import static org.junit.Assert.assertTrue;
+
+import java.time.OffsetTime;
+import java.time.ZoneOffset;
+
+import org.junit.Test;
+
+public class OffsetTimeExampleUnitTest {
+
+    OffsetTimeExample offsetTimeExample = new OffsetTimeExample();
+
+    @Test
+    public void givenZoneOffset_whenGetCurrentTime_thenResultHasZone() {
+        String offset = "+02:00";
+        OffsetTime time = offsetTimeExample.getCurrentTimeByZoneOffset(offset);
+
+        assertTrue(time.getOffset()
+            .equals(ZoneOffset.of(offset)));
+    }
+}

core-java/src/test/java/com/baeldung/zoneddatetime/ZoneDateTimeExampleUnitTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.zoneddatetime;
+
+import static org.junit.Assert.assertTrue;
+
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+
+import org.junit.Test;
+
+public class ZoneDateTimeExampleUnitTest {
+
+    ZoneDateTimeExample zoneDateTimeExample = new ZoneDateTimeExample();
+
+    @Test
+    public void givenZone_whenGetCurrentTime_thenResultHasZone() {
+        String zone = "Europe/Berlin";
+        ZonedDateTime time = zoneDateTimeExample.getCurrentTimeByZoneId(zone);
+
+        assertTrue(time.getZone()
+            .equals(ZoneId.of(zone)));
+    }
+
+    @Test
+    public void givenZones_whenConvertDateByZone_thenGetConstantDiff() {
+        String sourceZone = "Europe/Berlin";
+        String destZone = "Asia/Tokyo";
+        ZonedDateTime sourceDate = zoneDateTimeExample.getCurrentTimeByZoneId(sourceZone);
+        ZonedDateTime destDate = zoneDateTimeExample.convertZonedDateTime(sourceDate, destZone);
+        
+        assertTrue(sourceDate.toInstant()
+            .compareTo(destDate.toInstant()) == 0);
+    }
+}

core-kotlin/README.md

@@ -8,7 +8,6 @@
 - [Generics in Kotlin](http://www.baeldung.com/kotlin-generics)
 - [Introduction to Kotlin Coroutines](http://www.baeldung.com/kotlin-coroutines)
 - [Destructuring Declarations in Kotlin](http://www.baeldung.com/kotlin-destructuring-declarations)
-- [Kotlin with Mockito](http://www.baeldung.com/kotlin-mockito)
 - [Lazy Initialization in Kotlin](http://www.baeldung.com/kotlin-lazy-initialization)
 - [Overview of Kotlin Collections API](http://www.baeldung.com/kotlin-collections-api)
 - [Converting a List to Map in Kotlin](http://www.baeldung.com/kotlin-list-to-map)
@@ -19,8 +18,6 @@
 - [Extension Methods in Kotlin](http://www.baeldung.com/kotlin-extension-methods)
 - [Infix Functions in Kotlin](http://www.baeldung.com/kotlin-infix-functions)
 - [Try-with-resources in Kotlin](http://www.baeldung.com/kotlin-try-with-resources)
-- [HTTP Requests with Kotlin and khttp](http://www.baeldung.com/kotlin-khttp)
-- [Kotlin Dependency Injection with Kodein](http://www.baeldung.com/kotlin-kodein-dependency-injection)
 - [Regular Expressions in Kotlin](http://www.baeldung.com/kotlin-regular-expressions)
 - [Objects in Kotlin](http://www.baeldung.com/kotlin-objects)
 - [Reading from a File in Kotlin](http://www.baeldung.com/kotlin-read-file)
@@ -28,13 +25,12 @@
 - [Filtering Kotlin Collections](http://www.baeldung.com/kotlin-filter-collection)
 - [Writing to a File in Kotlin](http://www.baeldung.com/kotlin-write-file)
 - [Lambda Expressions in Kotlin](http://www.baeldung.com/kotlin-lambda-expressions)
-- [Writing Specifications with Kotlin and Spek](http://www.baeldung.com/kotlin-spek)
-- [Processing JSON with Kotlin and Klaxson](http://www.baeldung.com/kotlin-json-klaxson)
 - [Kotlin String Templates](http://www.baeldung.com/kotlin-string-template)
-- [Java EE 8 Security API](http://www.baeldung.com/java-ee-8-security)
-- [Kotlin with Ktor](http://www.baeldung.com/kotlin-ktor)
 - [Working with Enums in Kotlin](http://www.baeldung.com/kotlin-enum)
 - [Create a Java and Kotlin Project with Maven](http://www.baeldung.com/kotlin-maven-java-project)
 - [Reflection with Kotlin](http://www.baeldung.com/kotlin-reflection)
 - [Get a Random Number in Kotlin](http://www.baeldung.com/kotlin-random-number)
 - [Idiomatic Logging in Kotlin](http://www.baeldung.com/kotlin-logging)
+- [Kotlin Constructors](https://www.baeldung.com/kotlin-constructors)
+- [Creational Design Patterns in Kotlin: Builder](https://www.baeldung.com/kotlin-builder-pattern)
+- [Kotlin Nested and Inner Classes](https://www.baeldung.com/kotlin-inner-classes)

core-kotlin/build.gradle

@@ -6,7 +6,6 @@ version '1.0-SNAPSHOT'
 
 buildscript {
     ext.kotlin_version = '1.2.41'
-    ext.ktor_version = '0.9.2'
 
     repositories {
         mavenCentral()
@@ -44,14 +43,6 @@ sourceSets {
 }
 
 dependencies {
-    compile "io.ktor:ktor-server-netty:$ktor_version"
     compile "ch.qos.logback:logback-classic:1.2.1"
-    compile "io.ktor:ktor-gson:$ktor_version"
     testCompile group: 'junit', name: 'junit', version: '4.12'
-    implementation 'com.beust:klaxon:3.0.1'
-
-}
-task runServer(type: JavaExec) {
-    main = 'APIServer'
-   classpath = sourceSets.main.runtimeClasspath
 }

core-kotlin/kotlin-ktor/webapp/WEB-INF/web.xml

@@ -1,35 +0,0 @@
-<?xml version="1.0" encoding="ISO-8859-1" ?>
-
-<web-app xmlns="http://java.sun.com/xml/ns/javaee"
-  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
-  version="3.0">
-  <!-- path to application.conf file, required -->
-  <!-- note that this file is always loaded as an absolute path from the classpath -->
-  <context-param>
-    <param-name>io.ktor.ktor.config</param-name>
-    <param-value>application.conf</param-value>
-  </context-param>
-
-  <servlet>
-    <display-name>KtorServlet</display-name>
-    <servlet-name>KtorServlet</servlet-name>
-    <servlet-class>io.ktor.server.servlet.ServletApplicationEngine</servlet-class>
-
-    <!-- required! -->
-    <async-supported>true</async-supported>
-
-    <!-- 100mb max file upload, optional -->
-    <multipart-config>
-      <max-file-size>304857600</max-file-size>
-      <max-request-size>304857600</max-request-size>
-      <file-size-threshold>0</file-size-threshold>
-    </multipart-config>
-  </servlet>
-
-  <servlet-mapping>
-    <servlet-name>KtorServlet</servlet-name>
-    <url-pattern>/</url-pattern>
-  </servlet-mapping>
-
-</web-app>

core-kotlin/pom.xml

@@ -12,33 +12,7 @@
         <relativePath>../parent-kotlin</relativePath>
     </parent>
 
-    <repositories>
-        <repository>
-            <id>exposed</id>
-            <name>exposed</name>
-            <url>https://dl.bintray.com/kotlin/exposed</url>
-        </repository>
-    </repositories>
-
     <dependencies>
-        <dependency>
-            <groupId>org.jetbrains.spek</groupId>
-            <artifactId>spek-api</artifactId>
-            <version>1.1.5</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.jetbrains.spek</groupId>
-            <artifactId>spek-subject-extension</artifactId>
-            <version>1.1.5</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.jetbrains.spek</groupId>
-            <artifactId>spek-junit-platform-engine</artifactId>
-            <version>1.1.5</version>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-math3</artifactId>
@@ -50,56 +24,52 @@
             <version>${junit.platform.version}</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>khttp</groupId>
-            <artifactId>khttp</artifactId>
-            <version>${khttp.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>com.nhaarman</groupId>
-            <artifactId>mockito-kotlin</artifactId>
-            <version>${mockito-kotlin.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.github.salomonbrys.kodein</groupId>
-            <artifactId>kodein</artifactId>
-            <version>${kodein.version}</version>
-        </dependency>
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
             <version>${assertj.version}</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>com.beust</groupId>
-            <artifactId>klaxon</artifactId>
-            <version>${klaxon.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.jetbrains.exposed</groupId>
-            <artifactId>exposed</artifactId>
-            <version>${exposed.version}</version>
-        </dependency>
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
             <version>${h2database.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.github.kittinunf.fuel</groupId>
+            <artifactId>fuel</artifactId>
+            <version>${fuel.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.github.kittinunf.fuel</groupId>
+            <artifactId>fuel-gson</artifactId>
+            <version>${fuel.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.github.kittinunf.fuel</groupId>
+            <artifactId>fuel-rxjava</artifactId>
+            <version>${fuel.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.github.kittinunf.fuel</groupId>
+            <artifactId>fuel-coroutines</artifactId>
+            <version>${fuel.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>nl.komponents.kovenant</groupId>
+            <artifactId>kovenant</artifactId>
+            <version>3.3.0</version>
+            <type>pom</type>
+        </dependency>
     </dependencies>
 
     <properties>
-        <mockito-kotlin.version>1.5.0</mockito-kotlin.version>
-        <kodein.version>4.1.0</kodein.version>
-        <klaxon.version>3.0.4</klaxon.version>
-        <khttp.version>0.1.0</khttp.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <junit.platform.version>1.1.1</junit.platform.version>
         <junit.vintage.version>5.2.0</junit.vintage.version>
         <assertj.version>3.10.0</assertj.version>
         <h2database.version>1.4.197</h2database.version>
-        <exposed.version>0.10.4</exposed.version>
+        <fuel.version>1.15.0</fuel.version>
     </properties>
 
 </project>

core-kotlin/src/main/kotlin/com/baeldung/fuel/Interceptors.kt

@@ -0,0 +1,11 @@
+package com.baeldung.fuel
+
+import com.github.kittinunf.fuel.core.Request
+
+fun tokenInterceptor() = {
+    next: (Request) -> Request ->
+    { req: Request ->
+        req.header(mapOf("Authorization" to "Bearer AbCdEf123456"))
+        next(req)
+    }
+}

core-kotlin/src/main/kotlin/com/baeldung/fuel/Post.kt

@@ -0,0 +1,15 @@
+package com.baeldung.fuel
+
+import com.github.kittinunf.fuel.core.ResponseDeserializable
+import com.google.gson.Gson
+
+data class Post(var userId:Int,
+                var id:Int,
+                var title:String,
+                var body:String){
+
+
+    class Deserializer : ResponseDeserializable<Array<Post>> {
+        override fun deserialize(content: String): Array<Post> = Gson().fromJson(content, Array<Post>::class.java)
+    }
+}

core-kotlin/src/main/kotlin/com/baeldung/fuel/PostRoutingAPI.kt

@@ -0,0 +1,42 @@
+package com.baeldung.fuel
+
+import com.github.kittinunf.fuel.core.Method
+import com.github.kittinunf.fuel.util.FuelRouting
+
+sealed class PostRoutingAPI : FuelRouting {
+
+    override val basePath = "https://jsonplaceholder.typicode.com"
+
+    class posts(val id: String, override val body: String?): PostRoutingAPI()
+
+    class comments(val postId: String, override val body: String?): PostRoutingAPI()
+
+    override val method: Method
+        get() {
+            return when(this) {
+                is PostRoutingAPI.posts -> Method.GET
+                is PostRoutingAPI.comments -> Method.GET
+            }
+        }
+
+    override val path: String
+        get() {
+            return when(this) {
+                is PostRoutingAPI.posts -> "/posts"
+                is PostRoutingAPI.comments -> "/comments"
+            }
+        }
+
+    override val params: List<Pair<String, Any?>>?
+        get() {
+            return when(this) {
+                is PostRoutingAPI.posts -> listOf("id" to this.id)
+                is PostRoutingAPI.comments -> listOf("postId" to this.postId)
+            }
+        }
+
+    override val headers: Map<String, String>?
+        get() {
+            return null
+        }
+}

core-kotlin/src/main/kotlin/com/baeldung/ktor/APIServer.kt

@@ -1,73 +0,0 @@
-@file:JvmName("APIServer")
-
-
-import io.ktor.application.call
-import io.ktor.application.install
-import io.ktor.features.CallLogging
-import io.ktor.features.ContentNegotiation
-import io.ktor.features.DefaultHeaders
-import io.ktor.gson.gson
-import io.ktor.request.path
-import io.ktor.request.receive
-import io.ktor.response.respond
-import io.ktor.routing.*
-import io.ktor.server.engine.embeddedServer
-import io.ktor.server.netty.Netty
-import org.slf4j.event.Level
-
-data class Author(val name: String, val website: String)
-data class ToDo(var id: Int, val name: String, val description: String, val completed: Boolean)
-
-fun main(args: Array<String>) {
-
-    val toDoList = ArrayList<ToDo>();
-    val jsonResponse = """{
-            "id": 1,
-            "task": "Pay waterbill",
-            "description": "Pay water bill today",
-        }"""
-
-
-    embeddedServer(Netty, 8080) {
-        install(DefaultHeaders) {
-            header("X-Developer", "Baeldung")
-        }
-        install(CallLogging) {
-            level = Level.DEBUG
-            filter { call -> call.request.path().startsWith("/todo") }
-            filter { call -> call.request.path().startsWith("/author") }
-        }
-        install(ContentNegotiation) {
-            gson {
-                setPrettyPrinting()
-            }
-        }
-        routing() {
-            route("/todo") {
-                post {
-                    var toDo = call.receive<ToDo>();
-                    toDo.id = toDoList.size;
-                    toDoList.add(toDo);
-                    call.respond("Added")
-
-                }
-                delete("/{id}") {
-                    call.respond(toDoList.removeAt(call.parameters["id"]!!.toInt()));
-                }
-                get("/{id}") {
-
-                    call.respond(toDoList[call.parameters["id"]!!.toInt()]);
-                }
-                get {
-                    call.respond(toDoList);
-                }
-            }
-        get("/author"){
-            call.respond(Author("Baeldung","baeldung.com"));
-
-        }
-
-
-        }
-    }.start(wait = true)
-}

core-kotlin/src/test/kotlin/com/baeldung/builder/BuilderPatternUnitTest.kt

@@ -93,6 +93,7 @@ internal class BuilderPatternUnitTest {
         Assertions.assertNull(foodOrder.fish)
     }
 
+
     @Test
     fun whenBuildingFoodOrderApplySettingValues_thenFieldsNotNull() {
 

core-kotlin/src/test/kotlin/com/baeldung/fuel/FuelHttpUnitTest.kt

@@ -0,0 +1,286 @@
+package com.baeldung.fuel
+
+import awaitObjectResult
+import awaitStringResponse
+import com.github.kittinunf.fuel.Fuel
+import com.github.kittinunf.fuel.core.FuelManager
+import com.github.kittinunf.fuel.core.Request
+import com.github.kittinunf.fuel.core.interceptors.cUrlLoggingRequestInterceptor
+import com.github.kittinunf.fuel.gson.responseObject
+import com.github.kittinunf.fuel.httpGet
+import com.github.kittinunf.fuel.rx.rx_object
+import com.google.gson.Gson
+import kotlinx.coroutines.experimental.runBlocking
+import org.junit.jupiter.api.Assertions
+import org.junit.jupiter.api.Test
+import java.io.File
+import java.util.concurrent.CountDownLatch
+
+internal class FuelHttpUnitTest {
+
+    @Test
+    fun whenMakingAsyncHttpGetRequest_thenResponseNotNullAndErrorNullAndStatusCode200() {
+
+        val latch = CountDownLatch(1)
+
+        "http://httpbin.org/get".httpGet().response{
+            request, response, result ->
+
+            val (data, error) = result
+
+            Assertions.assertNull(error)
+            Assertions.assertNotNull(data)
+            Assertions.assertEquals(200,response.statusCode)
+
+            latch.countDown()
+        }
+
+        latch.await()
+
+    }
+
+    @Test
+    fun whenMakingSyncHttpGetRequest_thenResponseNotNullAndErrorNullAndStatusCode200() {
+
+        val (request, response, result) = "http://httpbin.org/get".httpGet().response()
+        val (data, error) = result
+
+        Assertions.assertNull(error)
+        Assertions.assertNotNull(data)
+        Assertions.assertEquals(200,response.statusCode)
+
+    }
+
+    @Test
+    fun whenMakingSyncHttpGetURLEncodedRequest_thenResponseNotNullAndErrorNullAndStatusCode200() {
+
+        val (request, response, result) =
+          "https://jsonplaceholder.typicode.com/posts"
+          .httpGet(listOf("id" to "1")).response()
+        val (data, error) = result
+
+        Assertions.assertNull(error)
+        Assertions.assertNotNull(data)
+        Assertions.assertEquals(200,response.statusCode)
+
+    }
+
+    @Test
+    fun whenMakingAsyncHttpPostRequest_thenResponseNotNullAndErrorNullAndStatusCode200() {
+
+        val latch = CountDownLatch(1)
+
+        Fuel.post("http://httpbin.org/post").response{
+            request, response, result ->
+
+            val (data, error) = result
+
+            Assertions.assertNull(error)
+            Assertions.assertNotNull(data)
+            Assertions.assertEquals(200,response.statusCode)
+
+            latch.countDown()
+        }
+
+        latch.await()
+
+    }
+
+    @Test
+    fun whenMakingSyncHttpPostRequest_thenResponseNotNullAndErrorNullAndStatusCode200() {
+
+        val (request, response, result) = Fuel.post("http://httpbin.org/post").response()
+        val (data, error) = result
+
+        Assertions.assertNull(error)
+        Assertions.assertNotNull(data)
+        Assertions.assertEquals(200,response.statusCode)
+    }
+
+    @Test
+    fun whenMakingSyncHttpPostRequestwithBody_thenResponseNotNullAndErrorNullAndStatusCode200() {
+
+        val (request, response, result) = Fuel.post("https://jsonplaceholder.typicode.com/posts")
+          .body("{ \"title\" : \"foo\",\"body\" : \"bar\",\"id\" : \"1\"}")
+          .response()
+
+        val (data, error) = result
+
+        Assertions.assertNull(error)
+        Assertions.assertNotNull(data)
+        Assertions.assertEquals(201,response.statusCode)
+    }
+
+    @Test
+    fun givenFuelInstance_whenMakingSyncHttpGetRequest_thenResponseNotNullAndErrorNullAndStatusCode200() {
+
+        FuelManager.instance.basePath = "http://httpbin.org"
+        FuelManager.instance.baseHeaders = mapOf("OS" to "macOS High Sierra")
+
+        FuelManager.instance.addRequestInterceptor(cUrlLoggingRequestInterceptor())
+        FuelManager.instance.addRequestInterceptor(tokenInterceptor())
+
+
+        val (request, response, result) = "/get"
+          .httpGet().response()
+        val (data, error) = result
+
+        Assertions.assertNull(error)
+        Assertions.assertNotNull(data)
+        Assertions.assertEquals(200,response.statusCode)
+    }
+
+    @Test
+    fun givenInterceptors_whenMakingSyncHttpGetRequest_thenResponseNotNullAndErrorNullAndStatusCode200() {
+
+        FuelManager.instance.basePath = "http://httpbin.org"
+        FuelManager.instance.addRequestInterceptor(cUrlLoggingRequestInterceptor())
+        FuelManager.instance.addRequestInterceptor(tokenInterceptor())
+
+        val (request, response, result) = "/get"
+                .httpGet().response()
+        val (data, error) = result
+
+        Assertions.assertNull(error)
+        Assertions.assertNotNull(data)
+        Assertions.assertEquals(200,response.statusCode)
+    }
+
+    @Test
+    fun whenDownloadFile_thenCreateFileResponseNotNullAndErrorNullAndStatusCode200() {
+
+        Fuel.download("http://httpbin.org/bytes/32768").destination { response, url ->
+            File.createTempFile("temp", ".tmp")
+        }.response{
+            request, response, result ->
+
+            val (data, error) = result
+            Assertions.assertNull(error)
+            Assertions.assertNotNull(data)
+            Assertions.assertEquals(200,response.statusCode)
+        }
+    }
+
+    @Test
+    fun whenDownloadFilewithProgressHandler_thenCreateFileResponseNotNullAndErrorNullAndStatusCode200() {
+
+        val (request, response, result) = Fuel.download("http://httpbin.org/bytes/327680")
+          .destination { response, url -> File.createTempFile("temp", ".tmp")
+        }.progress { readBytes, totalBytes ->
+            val progress = readBytes.toFloat() / totalBytes.toFloat()
+        }.response ()
+
+        val (data, error) = result
+        Assertions.assertNull(error)
+        Assertions.assertNotNull(data)
+        Assertions.assertEquals(200,response.statusCode)
+
+
+    }
+
+    @Test
+    fun whenMakeGetRequest_thenDeserializePostwithGson() {
+
+        val latch = CountDownLatch(1)
+
+        "https://jsonplaceholder.typicode.com/posts/1".httpGet().responseObject<Post> { _,_, result ->
+            val post = result.component1()
+            Assertions.assertEquals(1, post?.userId)
+            latch.countDown()
+        }
+
+        latch.await()
+
+    }
+
+    @Test
+    fun whenMakePOSTRequest_thenSerializePostwithGson() {
+
+        val post = Post(1,1, "Lorem", "Lorem Ipse dolor sit amet")
+
+        val (request, response, result) = Fuel.post("https://jsonplaceholder.typicode.com/posts")
+                .header("Content-Type" to "application/json")
+                .body(Gson().toJson(post).toString())
+                .response()
+
+        Assertions.assertEquals(201,response.statusCode)
+
+    }
+
+    @Test
+    fun whenMakeGETRequestWithRxJava_thenDeserializePostwithGson() {
+
+        val latch = CountDownLatch(1)
+
+
+        "https://jsonplaceholder.typicode.com/posts?id=1"
+                .httpGet().rx_object(Post.Deserializer()).subscribe{
+                    res, throwable ->
+
+                    val post = res.component1()
+                    Assertions.assertEquals(1, post?.get(0)?.userId)
+                    latch.countDown()
+                }
+
+        latch.await()
+
+    }
+
+    @Test
+    fun whenMakeGETRequestUsingCoroutines_thenResponseStatusCode200() {
+
+        runBlocking {
+            val (request, response, result) = Fuel.get("http://httpbin.org/get").awaitStringResponse()
+
+            result.fold({ data ->
+                Assertions.assertEquals(200, response.statusCode)
+
+            }, { error -> })
+        }
+
+    }
+
+    @Test
+    fun whenMakeGETRequestUsingCoroutines_thenDeserializeResponse() {
+
+
+        runBlocking {
+            Fuel.get("https://jsonplaceholder.typicode.com/posts?id=1").awaitObjectResult(Post.Deserializer())
+                    .fold({ data ->
+                        Assertions.assertEquals(1, data.get(0).userId)
+                    }, { error -> })
+        }
+
+    }
+
+    @Test
+    fun whenMakeGETPostRequestUsingRoutingAPI_thenDeserializeResponse() {
+
+        val latch = CountDownLatch(1)
+
+        Fuel.request(PostRoutingAPI.posts("1",null))
+          .responseObject(Post.Deserializer()) {
+              request, response, result ->
+              Assertions.assertEquals(1, result.component1()?.get(0)?.userId)
+              latch.countDown()
+          }
+
+        latch.await()
+    }
+
+    @Test
+    fun whenMakeGETCommentRequestUsingRoutingAPI_thenResponseStausCode200() {
+
+        val latch = CountDownLatch(1)
+
+        Fuel.request(PostRoutingAPI.comments("1",null))
+          .responseString { request, response, result ->
+            Assertions.assertEquals(200, response.statusCode)
+            latch.countDown()
+          }
+
+        latch.await()
+    }
+
+
+}

core-kotlin/src/test/kotlin/com/baeldung/kotlin/KovenantTest.kt

@@ -0,0 +1,191 @@
+package com.baeldung.kotlin
+
+import nl.komponents.kovenant.*
+import nl.komponents.kovenant.Kovenant.deferred
+import nl.komponents.kovenant.combine.and
+import nl.komponents.kovenant.combine.combine
+import org.junit.Assert
+import org.junit.Before
+import org.junit.Test
+import java.io.IOException
+import java.util.*
+import java.util.concurrent.TimeUnit
+
+class KovenantTest {
+    @Before
+    fun setupTestMode() {
+        Kovenant.testMode { error ->
+            println("An unexpected error occurred")
+            Assert.fail(error.message)
+        }
+    }
+
+    @Test
+    fun testSuccessfulDeferred() {
+        val def = deferred<Long, Exception>()
+        Assert.assertFalse(def.promise.isDone())
+
+        def.resolve(1L)
+        Assert.assertTrue(def.promise.isDone())
+        Assert.assertTrue(def.promise.isSuccess())
+        Assert.assertFalse(def.promise.isFailure())
+    }
+
+    @Test
+    fun testFailedDeferred() {
+        val def = deferred<Long, Exception>()
+        Assert.assertFalse(def.promise.isDone())
+
+        def.reject(RuntimeException())
+        Assert.assertTrue(def.promise.isDone())
+        Assert.assertFalse(def.promise.isSuccess())
+        Assert.assertTrue(def.promise.isFailure())
+    }
+
+    @Test
+    fun testResolveDeferredTwice() {
+        val def = deferred<Long, Exception>()
+        def.resolve(1L)
+        try {
+            def.resolve(1L)
+        } catch (e: AssertionError) {
+            // Expected.
+            // This is slightly unusual. The AssertionError comes from Assert.fail() from setupTestMode()
+        }
+    }
+
+    @Test
+    fun testSuccessfulTask() {
+        val promise = task { 1L }
+        Assert.assertTrue(promise.isDone())
+        Assert.assertTrue(promise.isSuccess())
+        Assert.assertFalse(promise.isFailure())
+    }
+
+    @Test
+    fun testFailedTask() {
+        val promise = task { throw RuntimeException() }
+        Assert.assertTrue(promise.isDone())
+        Assert.assertFalse(promise.isSuccess())
+        Assert.assertTrue(promise.isFailure())
+    }
+
+    @Test
+    fun testCallbacks() {
+        val promise = task { 1L }
+
+        promise.success {
+            println("This was a success")
+            Assert.assertEquals(1L, it)
+        }
+
+        promise.fail {
+            println(it)
+            Assert.fail("This shouldn't happen")
+        }
+
+        promise.always {
+            println("This always happens")
+        }
+    }
+
+    @Test
+    fun testGetValues() {
+        val promise = task { 1L }
+        Assert.assertEquals(1L, promise.get())
+    }
+
+    @Test
+    fun testAllSucceed() {
+        val numbers = all(
+                task { 1L },
+                task { 2L },
+                task { 3L }
+        )
+
+        Assert.assertEquals(listOf(1L, 2L, 3L), numbers.get())
+    }
+
+    @Test
+    fun testOneFails() {
+        val runtimeException = RuntimeException()
+
+        val numbers = all(
+                task { 1L },
+                task { 2L },
+                task { throw runtimeException }
+        )
+
+        Assert.assertEquals(runtimeException, numbers.getError())
+    }
+
+    @Test
+    fun testAnySucceeds() {
+        val promise = any(
+                task {
+                    TimeUnit.SECONDS.sleep(3)
+                    1L
+                },
+                task {
+                    TimeUnit.SECONDS.sleep(2)
+                    2L
+                },
+                task {
+                    TimeUnit.SECONDS.sleep(1)
+                    3L
+                }
+        )
+
+        Assert.assertTrue(promise.isDone())
+        Assert.assertTrue(promise.isSuccess())
+        Assert.assertFalse(promise.isFailure())
+    }
+
+    @Test
+    fun testAllFails() {
+        val runtimeException = RuntimeException()
+        val ioException = IOException()
+        val illegalStateException = IllegalStateException()
+        val promise = any(
+                task {
+                    TimeUnit.SECONDS.sleep(3)
+                    throw runtimeException
+                },
+                task {
+                    TimeUnit.SECONDS.sleep(2)
+                    throw ioException
+                },
+                task {
+                    TimeUnit.SECONDS.sleep(1)
+                    throw illegalStateException
+                }
+        )
+
+        Assert.assertTrue(promise.isDone())
+        Assert.assertFalse(promise.isSuccess())
+        Assert.assertTrue(promise.isFailure())
+    }
+
+    @Test
+    fun testSimpleCombine() {
+        val promise = task { 1L } and task { "Hello" }
+        val result = promise.get()
+
+        Assert.assertEquals(1L, result.first)
+        Assert.assertEquals("Hello", result.second)
+    }
+
+    @Test
+    fun testLongerCombine() {
+        val promise = combine(
+                task { 1L },
+                task { "Hello" },
+                task { Currency.getInstance("USD") }
+        )
+        val result = promise.get()
+
+        Assert.assertEquals(1L, result.first)
+        Assert.assertEquals("Hello", result.second)
+        Assert.assertEquals(Currency.getInstance("USD"), result.third)
+    }
+}

core-kotlin/src/test/kotlin/com/baeldung/kotlin/KovenantTimeoutTest.kt

@@ -0,0 +1,38 @@
+package com.baeldung.kotlin
+
+import nl.komponents.kovenant.Promise
+import nl.komponents.kovenant.any
+import nl.komponents.kovenant.task
+import org.junit.Assert
+import org.junit.Ignore
+import org.junit.Test
+
+@Ignore
+// Note that this can not run in the same test run if KovenantTest has already been executed
+class KovenantTimeoutTest {
+    @Test
+    fun testTimeout() {
+        val promise = timedTask(1000) { "Hello" }
+        val result = promise.get()
+        Assert.assertEquals("Hello", result)
+    }
+
+    @Test
+    fun testTimeoutExpired() {
+        val promise = timedTask(1000) {
+            Thread.sleep(3000)
+            "Hello"
+        }
+        val result = promise.get()
+        Assert.assertNull(result)
+    }
+
+    fun <T> timedTask(millis: Long, body: () -> T) : Promise<T?, List<Exception>> {
+        val timeoutTask = task {
+            Thread.sleep(millis)
+            null
+        }
+        val activeTask = task(body = body)
+        return any(activeTask, timeoutTask)
+    }
+}

core-kotlin/src/test/kotlin/com/baeldung/kotlin/StringConcatenationTest.kt

@@ -0,0 +1,48 @@
+package com.baeldung.kotlin
+
+import org.junit.Test
+import kotlin.test.assertEquals
+
+class StringConcatenationTest {
+
+    @Test
+    fun givenTwoStrings_concatenateWithTemplates_thenEquals() {
+        val a = "Hello"
+        val b = "Baeldung"
+        val c = "$a $b"
+
+        assertEquals("Hello Baeldung", c)
+    }
+
+    @Test
+    fun givenTwoStrings_concatenateWithPlusOperator_thenEquals() {
+        val a = "Hello"
+        val b = "Baeldung"
+        val c = a + " " + b
+
+        assertEquals("Hello Baeldung", c)
+    }
+
+    @Test
+    fun givenTwoStrings_concatenateWithStringBuilder_thenEquals() {
+        val a = "Hello"
+        val b = "Baeldung"
+
+        val builder = StringBuilder()
+        builder.append(a).append(" ").append(b)
+
+        val c = builder.toString()
+
+        assertEquals("Hello Baeldung", c)
+    }
+
+    @Test
+    fun givenTwoStrings_concatenateWithPlusMethod_thenEquals() {
+        val a = "Hello"
+        val b = "Baeldung"
+        val c = a.plus(" ").plus(b)
+
+        assertEquals("Hello Baeldung", c)
+    }
+
+}

core-kotlin/src/test/kotlin/com/baeldung/kotlin/gson/GsonUnitTest.kt

@@ -0,0 +1,30 @@
+package com.baeldung.kotlin.gson
+
+import com.google.gson.Gson
+
+import org.junit.Assert
+import org.junit.Test
+
+class GsonUnitTest {
+
+    var gson = Gson()
+
+    @Test
+    fun givenObject_thenGetJSONString() {
+        var jsonString = gson.toJson(TestModel(1,"Test"))
+        Assert.assertEquals(jsonString, "{\"id\":1,\"description\":\"Test\"}")
+    }
+
+    @Test
+    fun givenJSONString_thenGetObject() {
+        var jsonString = "{\"id\":1,\"description\":\"Test\"}";
+        var testModel = gson.fromJson(jsonString, TestModel::class.java)
+        Assert.assertEquals(testModel.id, 1)
+        Assert.assertEquals(testModel.description, "Test")
+    }
+
+    data class TestModel(
+        val id: Int,
+        val description: String
+    )
+}

disruptor/pom.xml

@@ -36,22 +36,6 @@
             </resource>
         </resources>
         <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-dependency-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <id>copy-dependencies</id>
-                        <phase>prepare-package</phase>
-                        <goals>
-                            <goal>copy-dependencies</goal>
-                        </goals>
-                        <configuration>
-                            <outputDirectory>${project.build.directory}/libs</outputDirectory>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-jar-plugin</artifactId>

drools/pom.xml

@@ -48,12 +48,18 @@
             <artifactId>poi-ooxml</artifactId>
             <version>${apache-poi-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.optaplanner</groupId>
+            <artifactId>optaplanner-core</artifactId>
+            <version>${opta-planner-version}</version>
+        </dependency>
     </dependencies>
 
     <properties>
         <http-component-version>4.4.6</http-component-version>
         <drools-version>7.4.1.Final</drools-version>
         <apache-poi-version>3.13</apache-poi-version>
+        <opta-planner-version>7.10.0.Final</opta-planner-version>
     </properties>
 
 </project>

drools/src/main/java/com/baeldung/drools/optaplanner/CourseSchedule.java

@@ -0,0 +1,63 @@
+package com.baeldung.drools.optaplanner;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.optaplanner.core.api.domain.solution.PlanningEntityCollectionProperty;
+import org.optaplanner.core.api.domain.solution.PlanningScore;
+import org.optaplanner.core.api.domain.solution.PlanningSolution;
+import org.optaplanner.core.api.domain.solution.drools.ProblemFactCollectionProperty;
+import org.optaplanner.core.api.domain.valuerange.ValueRangeProvider;
+import org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScore;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@PlanningSolution
+public class CourseSchedule {
+
+    Logger logger = LoggerFactory.getLogger("CourseSchedule");
+
+    private List<Integer> roomList;
+    private List<Integer> periodList;
+    private List<Lecture> lectureList;
+    private HardSoftScore score;
+
+    public CourseSchedule(){
+        roomList = new ArrayList<>();
+        periodList = new ArrayList<>();
+        lectureList = new ArrayList<>();
+    }
+
+    @ValueRangeProvider(id = "availableRooms")
+    @ProblemFactCollectionProperty
+    public List<Integer> getRoomList() {
+        return roomList;
+    }
+
+    @ValueRangeProvider(id = "availablePeriods")
+    @ProblemFactCollectionProperty
+    public List<Integer> getPeriodList() {
+        return periodList;
+    }
+
+    @PlanningEntityCollectionProperty
+    public List<Lecture> getLectureList() {
+        return lectureList;
+    }
+
+    @PlanningScore
+    public HardSoftScore getScore() {
+        return score;
+    }
+
+    public void setScore(HardSoftScore score) {
+        this.score = score;
+    }
+
+    public void printCourseSchedule() {
+        lectureList.stream()
+                .map(c -> "Lecture in Room " + c.getRoomNumber().toString() + " during Period " + c.getPeriod().toString())
+                .forEach(k -> logger.info(k));
+    }
+
+}

drools/src/main/java/com/baeldung/drools/optaplanner/Lecture.java

@@ -0,0 +1,30 @@
+package com.baeldung.drools.optaplanner;
+
+import org.optaplanner.core.api.domain.entity.PlanningEntity;
+import org.optaplanner.core.api.domain.variable.PlanningVariable;
+
+@PlanningEntity
+public class Lecture {
+
+    private Integer roomNumber;
+    private Integer period;
+
+    @PlanningVariable(valueRangeProviderRefs = {"availablePeriods"})
+    public Integer getPeriod() {
+        return period;
+    }
+
+    @PlanningVariable(valueRangeProviderRefs = {"availableRooms"})
+    public Integer getRoomNumber() {
+        return roomNumber;
+    }
+
+    public void setPeriod(Integer period) {
+        this.period = period;
+    }
+
+    public void setRoomNumber(Integer roomNumber) {
+        this.roomNumber = roomNumber;
+    }
+
+}

drools/src/main/java/com/baeldung/drools/optaplanner/ScoreCalculator.java

@@ -0,0 +1,32 @@
+package com.baeldung.drools.optaplanner;
+
+import java.util.HashSet;
+
+import org.optaplanner.core.api.score.Score;
+import org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScore;
+import org.optaplanner.core.impl.score.director.easy.EasyScoreCalculator;
+
+public class ScoreCalculator implements EasyScoreCalculator<CourseSchedule> {
+
+    @Override
+    public Score calculateScore(CourseSchedule courseSchedule) {
+        int hardScore = 0;
+        int softScore = 0;
+
+        HashSet<String> occupiedRooms = new HashSet<>();
+        for (Lecture lecture : courseSchedule.getLectureList()) {
+            if(lecture.getPeriod() != null && lecture.getRoomNumber() != null) {
+                String roomInUse = lecture.getPeriod().toString() + ":" + lecture.getRoomNumber().toString();
+                if (occupiedRooms.contains(roomInUse)) {
+                    hardScore += -1;
+                } else {
+                    occupiedRooms.add(roomInUse);
+                }
+            } else {
+                hardScore += -1;
+            }
+        }
+
+        return HardSoftScore.valueOf(hardScore, softScore);
+    }
+}

drools/src/main/resources/courseSchedule.drl

@@ -0,0 +1,14 @@
+package com.baeldung.drools.optaplanner
+
+import com.baeldung.drools.optaplanner.Lecture;
+import org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScoreHolder;
+
+global HardSoftScoreHolder scoreHolder;
+
+rule "noNullRoomPeriod"
+    when
+        Lecture( roomNumber == null );
+        Lecture( period == null );
+    then
+        scoreHolder.addHardConstraintMatch(kcontext, -1);
+end

drools/src/main/resources/courseScheduleSolverConfigDrools.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<solver>
+    <scanAnnotatedClasses/>
+
+    <scoreDirectorFactory>
+        <scoreDrl>courseSchedule.drl</scoreDrl>
+    </scoreDirectorFactory>
+
+    <termination>
+        <secondsSpentLimit>10</secondsSpentLimit>
+    </termination>
+</solver>

drools/src/main/resources/courseScheduleSolverConfiguration.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<solver>
+    <scanAnnotatedClasses/>
+
+    <scoreDirectorFactory>
+        <easyScoreCalculatorClass>com.baeldung.drools.optaplanner.ScoreCalculator</easyScoreCalculatorClass>
+    </scoreDirectorFactory>
+
+    <termination>
+        <secondsSpentLimit>10</secondsSpentLimit>
+    </termination>
+</solver>

drools/src/test/java/com/baeldung/drools/optaplanner/OptaPlannerUnitTest.java

@@ -0,0 +1,49 @@
+package com.baeldung.drools.optaplanner;
+
+import java.util.Arrays;
+
+import org.junit.Assert;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.optaplanner.core.api.solver.Solver;
+import org.optaplanner.core.api.solver.SolverFactory;
+
+public class OptaPlannerUnitTest {
+
+    static CourseSchedule unsolvedCourseSchedule;
+
+    @BeforeAll
+    public static void setUp() {
+
+        unsolvedCourseSchedule = new CourseSchedule();
+
+        for(int i = 0; i < 10; i++){
+            unsolvedCourseSchedule.getLectureList().add(new Lecture());
+        }
+
+        unsolvedCourseSchedule.getPeriodList().addAll(Arrays.asList(new Integer[] { 1, 2, 3 }));
+        unsolvedCourseSchedule.getRoomList().addAll(Arrays.asList(new Integer[] { 1, 2 }));
+    }
+
+    @Test
+    public void test_whenCustomJavaSolver() {
+
+        SolverFactory<CourseSchedule> solverFactory = SolverFactory.createFromXmlResource("courseScheduleSolverConfiguration.xml");
+        Solver<CourseSchedule> solver = solverFactory.buildSolver();
+        CourseSchedule solvedCourseSchedule = solver.solve(unsolvedCourseSchedule);
+
+        Assert.assertNotNull(solvedCourseSchedule.getScore());
+        Assert.assertEquals(-4, solvedCourseSchedule.getScore().getHardScore());
+    }
+
+    @Test
+    public void test_whenDroolsSolver() {
+
+        SolverFactory<CourseSchedule> solverFactory = SolverFactory.createFromXmlResource("courseScheduleSolverConfigDrools.xml");
+        Solver<CourseSchedule> solver = solverFactory.buildSolver();
+        CourseSchedule solvedCourseSchedule = solver.solve(unsolvedCourseSchedule);
+
+        Assert.assertNotNull(solvedCourseSchedule.getScore());
+        Assert.assertEquals(0, solvedCourseSchedule.getScore().getHardScore());
+    }
+}

enterprise-patterns/README.md

@@ -1 +0,0 @@
-## Relevant articles:

enterprise-patterns/intercepting-filter-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/filters/AuditFilter.java

@@ -1,25 +0,0 @@
-package com.baeldung.enterprise.patterns.front.controller.filters;
-
-import javax.servlet.FilterChain;
-import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpSession;
-import java.io.IOException;
-
-public class AuditFilter extends BaseFilter {
-    @Override
-    public void doFilter(
-      ServletRequest request,
-      ServletResponse response,
-      FilterChain chain
-    ) throws IOException, ServletException {
-        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
-        HttpSession session = httpServletRequest.getSession(false);
-        if (session != null && session.getAttribute("username") != null) {
-            request.setAttribute("username", session.getAttribute("username"));
-        }
-        chain.doFilter(request, response);
-    }
-}

enterprise-patterns/intercepting-filter-pattern/src/main/java/com/baeldung/enterprise/patterns/front/controller/filters/VisitorCounterFilter.java

@@ -1,23 +0,0 @@
-package com.baeldung.enterprise.patterns.front.controller.filters;
-
-import javax.servlet.FilterChain;
-import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
-import javax.servlet.annotation.WebFilter;
-import java.io.IOException;
-
-@WebFilter(servletNames = "front-controller")
-public class VisitorCounterFilter extends BaseFilter {
-    private int counter;
-
-    @Override
-    public void doFilter(
-      ServletRequest request,
-      ServletResponse response,
-      FilterChain chain
-    ) throws IOException, ServletException {
-        request.setAttribute("counter", ++counter);
-        chain.doFilter(request, response);
-    }
-}

enterprise-patterns/pom.xml

@@ -1,19 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <groupId>com.baeldung.enterprise.patterns</groupId>
-    <artifactId>enterprise-patterns-parent</artifactId>
-    <packaging>pom</packaging>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <modules>
-        <module>spring-dispatcher-servlet</module>
-    </modules>
-
-</project>

gson/README.md

@@ -7,3 +7,4 @@
 - [Gson Deserialization Cookbook](http://www.baeldung.com/gson-deserialization-guide)
 - [Jackson vs Gson](http://www.baeldung.com/jackson-vs-gson)
 - [Exclude Fields from Serialization in Gson](http://www.baeldung.com/gson-exclude-fields-serialization)
+- [Save Data to a JSON File with Gson](https://www.baeldung.com/gson-save-file)

guava/README.md

@@ -33,3 +33,4 @@
 - [Using Guava CountingOutputStream](http://www.baeldung.com/guava-counting-outputstream)
 - [Hamcrest Text Matchers](http://www.baeldung.com/hamcrest-text-matchers)
 - [Quick Guide to the Guava RateLimiter](http://www.baeldung.com/guava-rate-limiter)
+- [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)

hazelcast/README.md

@@ -1,2 +1,3 @@
 ### Relevant Articles:
 - [Guide to Hazelcast with Java](http://www.baeldung.com/java-hazelcast)
+- [Introduction to Hazelcast Jet](https://www.baeldung.com/hazelcast-jet)

hibernate5/README.md

@@ -13,3 +13,4 @@
 - [Pessimistic Locking in JPA](http://www.baeldung.com/jpa-pessimistic-locking)
 - [Bootstrapping JPA Programmatically in Java](http://www.baeldung.com/java-bootstrap-jpa)
 - [Optimistic Locking in JPA](http://www.baeldung.com/jpa-optimistic-locking)
+- [Hibernate Entity Lifecycle](https://www.baeldung.com/hibernate-entity-lifecycle)

hibernate5/src/main/java/com/baeldung/hibernate/HibernateUtil.java

@@ -1,5 +1,11 @@
 package com.baeldung.hibernate;
 
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.net.URL;
+import java.util.Properties;
+
+import com.baeldung.hibernate.entities.DeptEmployee;
 import com.baeldung.hibernate.optimisticlocking.OptimisticLockingCourse;
 import com.baeldung.hibernate.optimisticlocking.OptimisticLockingStudent;
 import com.baeldung.hibernate.pessimisticlocking.Individual;
@@ -16,10 +22,30 @@ import org.hibernate.boot.MetadataSources;
 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
 import org.hibernate.service.ServiceRegistry;
 
-import java.io.FileInputStream;
+import com.baeldung.hibernate.pojo.Course;
-import java.io.IOException;
+import com.baeldung.hibernate.pojo.Employee;
-import java.net.URL;
+import com.baeldung.hibernate.pojo.EntityDescription;
-import java.util.Properties;
+import com.baeldung.hibernate.pojo.OrderEntry;
+import com.baeldung.hibernate.pojo.OrderEntryIdClass;
+import com.baeldung.hibernate.pojo.OrderEntryPK;
+import com.baeldung.hibernate.pojo.Person;
+import com.baeldung.hibernate.pojo.Phone;
+import com.baeldung.hibernate.pojo.PointEntity;
+import com.baeldung.hibernate.pojo.PolygonEntity;
+import com.baeldung.hibernate.pojo.Product;
+import com.baeldung.hibernate.pojo.Student;
+import com.baeldung.hibernate.pojo.TemporalValues;
+import com.baeldung.hibernate.pojo.User;
+import com.baeldung.hibernate.pojo.UserProfile;
+import com.baeldung.hibernate.pojo.inheritance.Animal;
+import com.baeldung.hibernate.pojo.inheritance.Bag;
+import com.baeldung.hibernate.pojo.inheritance.Book;
+import com.baeldung.hibernate.pojo.inheritance.Car;
+import com.baeldung.hibernate.pojo.inheritance.MyEmployee;
+import com.baeldung.hibernate.pojo.inheritance.MyProduct;
+import com.baeldung.hibernate.pojo.inheritance.Pen;
+import com.baeldung.hibernate.pojo.inheritance.Pet;
+import com.baeldung.hibernate.pojo.inheritance.Vehicle;
 
 public class HibernateUtil {
     private static SessionFactory sessionFactory;
@@ -72,6 +98,8 @@ public class HibernateUtil {
         metadataSources.addAnnotatedClass(PessimisticLockingCourse.class);
         metadataSources.addAnnotatedClass(com.baeldung.hibernate.pessimisticlocking.Customer.class);
         metadataSources.addAnnotatedClass(com.baeldung.hibernate.pessimisticlocking.Address.class);
+        metadataSources.addAnnotatedClass(DeptEmployee.class);
+        metadataSources.addAnnotatedClass(com.baeldung.hibernate.entities.Department.class);
         metadataSources.addAnnotatedClass(OptimisticLockingCourse.class);
         metadataSources.addAnnotatedClass(OptimisticLockingStudent.class);
 

hibernate5/src/main/java/com/baeldung/hibernate/entities/Department.java

@@ -0,0 +1,45 @@
+package com.baeldung.hibernate.entities;
+
+import java.util.List;
+
+import javax.persistence.*;
+
+@Entity
+public class Department {
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    private long id;
+
+    private String name;
+
+    @OneToMany(mappedBy="department")
+    private List<DeptEmployee> employees;
+
+    public Department(String name) {
+        this.name = name;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public List<DeptEmployee> getEmployees() {
+        return employees;
+    }
+
+    public void setEmployees(List<DeptEmployee> employees) {
+        this.employees = employees;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/entities/DeptEmployee.java

@@ -0,0 +1,65 @@
+package com.baeldung.hibernate.entities;
+
+import javax.persistence.*;
+
+@Entity
+public class DeptEmployee {
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    private long id;
+
+    private String employeeNumber;
+
+    private String designation;
+
+    private String name;
+
+    @ManyToOne
+    private Department department;
+    
+    public DeptEmployee(String name, String employeeNumber, Department department) {
+        this.name = name;
+        this.employeeNumber = employeeNumber;
+        this.department = department;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getEmployeeNumber() {
+        return employeeNumber;
+    }
+
+    public void setEmployeeNumber(String employeeNumber) {
+        this.employeeNumber = employeeNumber;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Department getDepartment() {
+        return department;
+    }
+
+    public void setDepartment(Department department) {
+        this.department = department;
+    }
+
+    public String getDesignation() {
+        return designation;
+    }
+
+    public void setDesignation(String designation) {
+        this.designation = designation;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/pojo/Result.java

@@ -0,0 +1,31 @@
+package com.baeldung.hibernate.pojo;
+
+public class Result {
+    private String employeeName;
+
+    private String departmentName;
+    
+    public Result(String employeeName, String departmentName) {
+        this.employeeName = employeeName;
+        this.departmentName = departmentName;
+    }
+
+    public Result() {
+    }
+
+    public String getEmployeeName() {
+        return employeeName;
+    }
+
+    public void setEmployeeName(String employeeName) {
+        this.employeeName = employeeName;
+    }
+
+    public String getDepartmentName() {
+        return departmentName;
+    }
+
+    public void setDepartmentName(String departmentName) {
+        this.departmentName = departmentName;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/proxy/BatchEmployee.java

@@ -0,0 +1,56 @@
+package com.baeldung.hibernate.proxy;
+
+import org.hibernate.annotations.BatchSize;
+
+import javax.persistence.*;
+import java.io.Serializable;
+
+@Entity
+@BatchSize(size = 5)
+public class BatchEmployee implements Serializable {
+
+    @Id
+    @GeneratedValue (strategy = GenerationType.SEQUENCE)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    private Boss boss;
+
+    @Column(name = "name")
+    private String name;
+
+    @Column(name = "surname")
+    private String surname;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Boss getBoss() {
+        return boss;
+    }
+
+    public void setBoss(Boss boss) {
+        this.boss = boss;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/proxy/Boss.java

@@ -0,0 +1,49 @@
+package com.baeldung.hibernate.proxy;
+
+import javax.persistence.*;
+import java.io.Serializable;
+
+@Entity
+public class Boss implements Serializable {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    private Long id;
+
+    @Column(name = "name")
+    private String name;
+
+    @Column(name = "surname")
+    private String surname;
+
+    public Boss() { }
+
+    public Boss(String name, String surname) {
+        this.name = name;
+        this.surname = surname;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/proxy/Employee.java

@@ -0,0 +1,53 @@
+package com.baeldung.hibernate.proxy;
+
+import javax.persistence.*;
+import java.io.Serializable;
+
+@Entity
+public class Employee implements Serializable {
+
+    @Id
+    @GeneratedValue (strategy = GenerationType.SEQUENCE)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    private Boss boss;
+
+    @Column(name = "name")
+    private String name;
+
+    @Column(name = "surname")
+    private String surname;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Boss getBoss() {
+        return boss;
+    }
+
+    public void setBoss(Boss boss) {
+        this.boss = boss;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/proxy/HibernateUtil.java

@@ -0,0 +1,57 @@
+package com.baeldung.hibernate.proxy;
+
+import org.apache.commons.lang3.StringUtils;
+import org.hibernate.SessionFactory;
+import org.hibernate.boot.Metadata;
+import org.hibernate.boot.MetadataSources;
+import org.hibernate.boot.SessionFactoryBuilder;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.service.ServiceRegistry;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.net.URL;
+import java.util.Properties;
+
+public class HibernateUtil {
+
+    private static SessionFactory sessionFactory;
+    private static String PROPERTY_FILE_NAME;
+
+    public static SessionFactory getSessionFactory(String propertyFileName) throws IOException {
+        PROPERTY_FILE_NAME = propertyFileName;
+        if (sessionFactory == null) {
+            ServiceRegistry serviceRegistry = configureServiceRegistry();
+            sessionFactory = getSessionFactoryBuilder(serviceRegistry).build();
+        }
+        return sessionFactory;
+    }
+
+    private static SessionFactoryBuilder getSessionFactoryBuilder(ServiceRegistry serviceRegistry) {
+        MetadataSources metadataSources = new MetadataSources(serviceRegistry);
+        metadataSources.addPackage("com.baeldung.hibernate.proxy");
+        metadataSources.addAnnotatedClass(Boss.class);
+        metadataSources.addAnnotatedClass(Employee.class);
+
+        Metadata metadata = metadataSources.buildMetadata();
+        return metadata.getSessionFactoryBuilder();
+
+    }
+
+    private static ServiceRegistry configureServiceRegistry() throws IOException {
+        Properties properties = getProperties();
+        return new StandardServiceRegistryBuilder().applySettings(properties)
+            .build();
+    }
+
+    private static Properties getProperties() throws IOException {
+        Properties properties = new Properties();
+        URL propertiesURL = Thread.currentThread()
+            .getContextClassLoader()
+            .getResource(StringUtils.defaultString(PROPERTY_FILE_NAME, "hibernate.properties"));
+        try (FileInputStream inputStream = new FileInputStream(propertiesURL.getFile())) {
+            properties.load(inputStream);
+        }
+        return properties;
+    }
+}

hibernate5/src/test/java/com/baeldung/hibernate/CustomClassIntegrationTest.java

@@ -0,0 +1,77 @@
+package com.baeldung.hibernate;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+import java.util.List;
+
+import com.baeldung.hibernate.entities.DeptEmployee;
+import org.hibernate.Session;
+import org.hibernate.Transaction;
+import org.hibernate.query.Query;
+import org.hibernate.transform.Transformers;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.hibernate.entities.Department;
+import com.baeldung.hibernate.pojo.Result;
+
+public class CustomClassIntegrationTest {
+
+    private Session session;
+
+    private Transaction transaction;
+
+    @BeforeEach
+    public void setUp() throws IOException {
+        session = HibernateUtil.getSessionFactory().openSession();
+        transaction = session.beginTransaction();
+        session.createNativeQuery("delete from manager").executeUpdate();
+        session.createNativeQuery("delete from department").executeUpdate();
+        Department department = new Department("Sales");
+        DeptEmployee employee = new DeptEmployee("John Smith", "001", department);
+        session.persist(department);
+        session.persist(employee);
+        transaction.commit();
+        transaction = session.beginTransaction();
+    }
+    
+    @Test
+    public void whenAllManagersAreSelected_ThenObjectGraphIsReturned() {
+        Query<DeptEmployee> query = session.createQuery("from com.baeldung.hibernate.entities.DeptEmployee");
+        List<DeptEmployee> deptEmployees = query.list();
+        DeptEmployee deptEmployee = deptEmployees.get(0);
+        assertEquals("John Smith", deptEmployee.getName());
+        assertEquals("Sales", deptEmployee.getDepartment().getName());
+    }
+    
+    @Test
+    public void whenIndividualPropertiesAreSelected_ThenObjectArrayIsReturned() {
+        Query query = session.createQuery("select m.name, m.department.name from com.baeldung.hibernate.entities.DeptEmployee m");
+        List managers = query.list();
+        Object[] manager = (Object[]) managers.get(0);
+        assertEquals("John Smith", manager[0]);
+        assertEquals("Sales", manager[1]);
+    }
+    
+    @Test
+    public void whenResultConstructorInSelect_ThenListOfResultIsReturned() {
+        Query<Result> query = session.createQuery("select new com.baeldung.hibernate.pojo.Result(m.name, m.department.name) "
+                + "from DeptEmployee m");
+        List<Result> results = query.list();
+        Result result = results.get(0);
+        assertEquals("John Smith", result.getEmployeeName());
+        assertEquals("Sales", result.getDepartmentName());
+    }
+    
+    @Test
+    public void whenResultTransformerOnQuery_ThenListOfResultIsReturned() {
+        Query query = session.createQuery("select m.name as employeeName, m.department.name as departmentName "
+                + "from com.baeldung.hibernate.entities.DeptEmployee m");
+        query.setResultTransformer(Transformers.aliasToBean(Result.class));
+        List<Result> results = query.list();
+        Result result = results.get(0);
+        assertEquals("John Smith", result.getEmployeeName());
+        assertEquals("Sales", result.getDepartmentName());   
+    }
+}