Merge remote-tracking branch 'eugenp/master'

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));
+    }
+
+}

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/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>

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/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/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-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/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-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/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-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)
@@ -28,11 +25,7 @@
 - [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)
@@ -40,5 +33,4 @@
 - [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)
-- [Guide to the Kotlin Exposed Framework](https://www.baeldung.com/kotlin-exposed-persistence)
+- [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>
@@ -50,38 +24,12 @@
             <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>${exposed.version}</version>
-        </dependency>
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
@@ -107,19 +55,20 @@
             <artifactId>fuel-coroutines</artifactId>
             <version>${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>
 

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/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)
+    }
+}

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>

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/proxy/HibernateProxyUnitTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.hibernate.proxy;
+
+import org.hibernate.*;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+import java.util.List;
+
+import static org.junit.Assert.fail;
+
+public class HibernateProxyUnitTest {
+
+    private Session session;
+
+    @Before
+    public void init(){
+        try {
+            session = HibernateUtil.getSessionFactory("hibernate.properties")
+                    .openSession();
+        } catch (HibernateException | IOException e) {
+            fail("Failed to initiate Hibernate Session [Exception:" + e.toString() + "]");
+        }
+
+        Boss boss = new Boss("Eduard", "Freud");
+        session.save(boss);
+    }
+
+    @After
+    public void close(){
+        if(session != null) {
+            session.close();
+        }
+    }
+
+    @Test(expected = NullPointerException.class)
+    public void givenAnInexistentEmployeeId_whenUseGetMethod_thenReturnNull() {
+        Employee employee = session.get(Employee.class, new Long(14));
+        assertNull(employee);
+        employee.getId();
+    }
+
+    @Test
+    public void givenAnInexistentEmployeeId_whenUseLoadMethod_thenReturnAProxy() {
+        Employee employee = session.load(Employee.class, new Long(14));
+        assertNotNull(employee);
+    }
+
+    @Test
+    public void givenABatchEmployeeList_whenSaveOne_thenSaveTheWholeBatch() {
+        Transaction transaction = session.beginTransaction();
+
+        for (long i = 1; i <= 5; i++) {
+            Employee employee = new Employee();
+            employee.setName("Employee " + i);
+            session.save(employee);
+        }
+
+        //After this line is possible to see all the insertions in the logs
+        session.flush();
+        session.clear();
+        transaction.commit();
+
+        transaction = session.beginTransaction();
+
+        List<Employee> employeeList = session.createQuery("from Employee")
+                                        .setCacheMode(CacheMode.IGNORE).getResultList();
+
+        assertEquals(employeeList.size(), 5);
+        transaction.commit();
+    }
+}

java-dates/pom.xml

@@ -61,23 +61,6 @@
         </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>

java-numbers/pom.xml

@@ -83,23 +83,6 @@
                 </configuration>
             </plugin>
 
-            <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-javadoc-plugin</artifactId>

java-numbers/src/main/java/com/baeldung/maths/BigDecimalDemo.java

@@ -0,0 +1,29 @@
+package com.baeldung.maths;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+public class BigDecimalDemo {
+
+    /** Calculate total amount to be paid for an item rounded to cents..
+     * @param quantity
+     * @param unitPrice
+     * @param discountRate
+     * @param taxRate
+     * @return
+     */
+    public static BigDecimal calculateTotalAmount(BigDecimal quantity,
+        BigDecimal unitPrice, BigDecimal discountRate, BigDecimal taxRate) {
+        BigDecimal amount = quantity.multiply(unitPrice);
+        BigDecimal discount = amount.multiply(discountRate);
+        BigDecimal discountedAmount = amount.subtract(discount);
+        BigDecimal tax = discountedAmount.multiply(taxRate);
+        BigDecimal total = discountedAmount.add(tax);
+
+        // round to 2 decimal places using HALF_EVEN
+        BigDecimal roundedTotal = total.setScale(2, RoundingMode.HALF_EVEN);
+
+        return roundedTotal;
+    }
+
+}

java-numbers/src/test/java/com/baeldung/maths/BigDecimalDemoUnitTest.java

@@ -0,0 +1,120 @@
+package com.baeldung.maths;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.math.MathContext;
+import java.math.RoundingMode;
+import java.util.Random;
+
+import org.junit.jupiter.api.Test;
+
+public class BigDecimalDemoUnitTest {
+
+    @Test
+    public void whenBigDecimalCreated_thenValueMatches() {
+        BigDecimal bdFromString = new BigDecimal("0.1");
+        BigDecimal bdFromCharArray = new BigDecimal(
+            new char[] { '3', '.', '1', '6', '1', '5' });
+        BigDecimal bdlFromInt = new BigDecimal(42);
+        BigDecimal bdFromLong = new BigDecimal(123412345678901L);
+        BigInteger bigInteger = BigInteger.probablePrime(100, new Random());
+        BigDecimal bdFromBigInteger = new BigDecimal(bigInteger);
+
+        assertEquals("0.1", bdFromString.toString());
+        assertEquals("3.1615", bdFromCharArray.toString());
+        assertEquals("42", bdlFromInt.toString());
+        assertEquals("123412345678901", bdFromLong.toString());
+        assertEquals(bigInteger.toString(), bdFromBigInteger.toString());
+    }
+
+    @Test
+    public void whenBigDecimalCreatedFromDouble_thenValueMayNotMatch() {
+        BigDecimal bdFromDouble = new BigDecimal(0.1d);
+        assertNotEquals("0.1", bdFromDouble.toString());
+    }
+
+    @Test
+    public void whenBigDecimalCreatedUsingValueOf_thenValueMatches() {
+        BigDecimal bdFromLong1 = BigDecimal.valueOf(123412345678901L);
+        BigDecimal bdFromLong2 = BigDecimal.valueOf(123412345678901L, 2);
+        BigDecimal bdFromDouble = BigDecimal.valueOf(0.1d);
+
+        assertEquals("123412345678901", bdFromLong1.toString());
+        assertEquals("1234123456789.01", bdFromLong2.toString());
+        assertEquals("0.1", bdFromDouble.toString());
+    }
+
+    @Test
+    public void whenEqualsCalled_thenSizeAndScaleMatched() {
+        BigDecimal bd1 = new BigDecimal("1.0");
+        BigDecimal bd2 = new BigDecimal("1.00");
+
+        assertFalse(bd1.equals(bd2));
+    }
+
+    @Test
+    public void whenComparingBigDecimals_thenExpectedResult() {
+        BigDecimal bd1 = new BigDecimal("1.0");
+        BigDecimal bd2 = new BigDecimal("1.00");
+        BigDecimal bd3 = new BigDecimal("2.0");
+
+        assertTrue(bd1.compareTo(bd3) < 0);
+        assertTrue(bd3.compareTo(bd1) > 0);
+        assertTrue(bd1.compareTo(bd2) == 0);
+        assertTrue(bd1.compareTo(bd3) <= 0);
+        assertTrue(bd1.compareTo(bd2) >= 0);
+        assertTrue(bd1.compareTo(bd3) != 0);
+    }
+
+    @Test
+    public void whenPerformingArithmetic_thenExpectedResult() {
+        BigDecimal bd1 = new BigDecimal("4.0");
+        BigDecimal bd2 = new BigDecimal("2.0");
+
+        BigDecimal sum = bd1.add(bd2);
+        BigDecimal difference = bd1.subtract(bd2);
+        BigDecimal quotient = bd1.divide(bd2);
+        BigDecimal product = bd1.multiply(bd2);
+
+        assertTrue(sum.compareTo(new BigDecimal("6.0")) == 0);
+        assertTrue(difference.compareTo(new BigDecimal("2.0")) == 0);
+        assertTrue(quotient.compareTo(new BigDecimal("2.0")) == 0);
+        assertTrue(product.compareTo(new BigDecimal("8.0")) == 0);
+    }
+
+    @Test
+    public void whenGettingAttributes_thenExpectedResult() {
+        BigDecimal bd = new BigDecimal("-12345.6789");
+
+        assertEquals(9, bd.precision());
+        assertEquals(4, bd.scale());
+        assertEquals(-1, bd.signum());
+    }
+
+    @Test
+    public void whenRoundingDecimal_thenExpectedResult() {
+        BigDecimal bd = new BigDecimal("2.5");
+        // Round to 1 digit using HALF_EVEN
+        BigDecimal rounded = bd
+            .round(new MathContext(1, RoundingMode.HALF_EVEN));
+
+        assertEquals("2", rounded.toString());
+    }
+
+    @Test
+    public void givenPurchaseTxn_whenCalculatingTotalAmount_thenExpectedResult() {
+        BigDecimal quantity = new BigDecimal("4.5");
+        BigDecimal unitPrice = new BigDecimal("2.69");
+        BigDecimal discountRate = new BigDecimal("0.10");
+        BigDecimal taxRate = new BigDecimal("0.0725");
+
+        BigDecimal amountToBePaid = BigDecimalDemo
+            .calculateTotalAmount(quantity, unitPrice, discountRate, taxRate);
+        assertEquals("11.68", amountToBePaid.toString());
+    }
+}

java-numbers/src/test/java/com/baeldung/maths/BigIntegerDemoUnitTest.java

@@ -0,0 +1,128 @@
+package com.baeldung.maths;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+import org.junit.jupiter.api.Test;
+
+public class BigIntegerDemoUnitTest {
+
+    @Test
+    public void whenBigIntegerCreatedFromConstructor_thenExpectedResult() {
+        BigInteger biFromString = new BigInteger("1234567890987654321");
+        BigInteger biFromByteArray = new BigInteger(
+            new byte[] { 64, 64, 64, 64, 64, 64 });
+        BigInteger biFromSignMagnitude = new BigInteger(-1,
+            new byte[] { 64, 64, 64, 64, 64, 64 });
+
+        assertEquals("1234567890987654321", biFromString.toString());
+        assertEquals("70644700037184", biFromByteArray.toString());
+        assertEquals("-70644700037184", biFromSignMagnitude.toString());
+    }
+
+    @Test
+    public void whenLongConvertedToBigInteger_thenValueMatches() {
+        BigInteger bi = BigInteger.valueOf(2305843009213693951L);
+
+        assertEquals("2305843009213693951", bi.toString());
+    }
+
+    @Test
+    public void givenBigIntegers_whentCompared_thenExpectedResult() {
+        BigInteger i = new BigInteger("123456789012345678901234567890");
+        BigInteger j = new BigInteger("123456789012345678901234567891");
+        BigInteger k = new BigInteger("123456789012345678901234567892");
+
+        assertTrue(i.compareTo(i) == 0);
+        assertTrue(j.compareTo(i) > 0);
+        assertTrue(j.compareTo(k) < 0);
+    }
+
+    @Test
+    public void givenBigIntegers_whenPerformingArithmetic_thenExpectedResult() {
+        BigInteger i = new BigInteger("4");
+        BigInteger j = new BigInteger("2");
+
+        BigInteger sum = i.add(j);
+        BigInteger difference = i.subtract(j);
+        BigInteger quotient = i.divide(j);
+        BigInteger product = i.multiply(j);
+
+        assertEquals(new BigInteger("6"), sum);
+        assertEquals(new BigInteger("2"), difference);
+        assertEquals(new BigInteger("2"), quotient);
+        assertEquals(new BigInteger("8"), product);
+    }
+
+    @Test
+    public void givenBigIntegers_whenPerformingBitOperations_thenExpectedResult() {
+        BigInteger i = new BigInteger("17");
+        BigInteger j = new BigInteger("7");
+
+        BigInteger and = i.and(j);
+        BigInteger or = i.or(j);
+        BigInteger not = j.not();
+        BigInteger xor = i.xor(j);
+        BigInteger andNot = i.andNot(j);
+        BigInteger shiftLeft = i.shiftLeft(1);
+        BigInteger shiftRight = i.shiftRight(1);
+
+        assertEquals(new BigInteger("1"), and);
+        assertEquals(new BigInteger("23"), or);
+        assertEquals(new BigInteger("-8"), not);
+        assertEquals(new BigInteger("22"), xor);
+        assertEquals(new BigInteger("16"), andNot);
+        assertEquals(new BigInteger("34"), shiftLeft);
+        assertEquals(new BigInteger("8"), shiftRight);
+    }
+
+    @Test
+    public void givenBigIntegers_whenPerformingBitManipulations_thenExpectedResult() {
+        BigInteger i = new BigInteger("1018");
+
+        int bitCount = i.bitCount();
+        int bitLength = i.bitLength();
+        int getLowestSetBit = i.getLowestSetBit();
+        boolean testBit3 = i.testBit(3);
+        BigInteger setBit12 = i.setBit(12);
+        BigInteger flipBit0 = i.flipBit(0);
+        BigInteger clearBit3 = i.clearBit(3);
+
+        assertEquals(8, bitCount);
+        assertEquals(10, bitLength);
+        assertEquals(1, getLowestSetBit);
+        assertEquals(true, testBit3);
+        assertEquals(new BigInteger("5114"), setBit12);
+        assertEquals(new BigInteger("1019"), flipBit0);
+        assertEquals(new BigInteger("1010"), clearBit3);
+    }
+
+    @Test
+    public void givenBigIntegers_whenModularCalculation_thenExpectedResult() {
+        BigInteger i = new BigInteger("31");
+        BigInteger j = new BigInteger("24");
+        BigInteger k = new BigInteger("16");
+
+        BigInteger gcd = j.gcd(k);
+        BigInteger multiplyAndmod = j.multiply(k)
+            .mod(i);
+        BigInteger modInverse = j.modInverse(i);
+        BigInteger modPow = j.modPow(k, i);
+
+        assertEquals(new BigInteger("8"), gcd);
+        assertEquals(new BigInteger("12"), multiplyAndmod);
+        assertEquals(new BigInteger("22"), modInverse);
+        assertEquals(new BigInteger("7"), modPow);
+    }
+
+    @Test
+    public void givenBigIntegers_whenPrimeOperations_thenExpectedResult() {
+        BigInteger i = BigInteger.probablePrime(100, new Random());
+
+        boolean isProbablePrime = i.isProbablePrime(1000);
+        assertEquals(true, isProbablePrime);
+    }
+}

java-streams/pom.xml

@@ -86,23 +86,6 @@
         </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>

java-streams/src/test/java/com/baeldung/streamordering/BenchmarkManualTest.java

@@ -15,7 +15,7 @@ import java.util.concurrent.TimeUnit;
 import java.util.stream.IntStream;
 
 
-public class BenchmarkUnitTest
+public class BenchmarkManualTest
 {
 
   public void

java-strings/README.md

@@ -26,3 +26,4 @@
 - [Convert a String to Title Case](http://www.baeldung.com/java-string-title-case)
 - [Compact Strings in Java 9](http://www.baeldung.com/java-9-compact-string)
 - [Java Check a String for Lowercase/Uppercase Letter, Special Character and Digit](https://www.baeldung.com/java-lowercase-uppercase-special-character-digit-regex)
+- [Convert java.util.Date to String](https://www.baeldung.com/java-util-date-to-string)

java-strings/pom.xml

@@ -71,23 +71,6 @@
         </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>

java-strings/src/main/java/com/baeldung/string/JoinerSplitter.java

@@ -2,6 +2,7 @@ package com.baeldung.string;
 
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -32,5 +33,12 @@ public class JoinerSplitter {
 				.mapToObj(item -> (char) item)
 				.collect(Collectors.toList());
 	}
+	
+	public static Map<String, String> arrayToMap(String[] arrayOfString) {
+		return Arrays.asList(arrayOfString)
+				.stream()
+				.map(str -> str.split(":"))
+				.collect(Collectors.<String[], String, String>toMap(str -> str[0], str -> str[1]));
+	}
 		
 }

java-strings/src/test/java/com/baeldung/string/JoinerSplitterUnitTest.java

@@ -3,7 +3,9 @@ package com.baeldung.string;
 import org.junit.Test;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import static org.junit.Assert.assertEquals;
 
@@ -62,5 +64,20 @@ public class JoinerSplitterUnitTest {
         assertEquals(result, expectation);
 
     }
+    
+    @Test
+    public void givenStringArray_transformedToStream_convertToMap() {
+
+        String[] programming_languages = new String[] {"language:java","os:linux","editor:emacs"};
+        
+        Map<String,String> expectation=new HashMap<>();
+        expectation.put("language", "java");
+        expectation.put("os", "linux");
+        expectation.put("editor", "emacs");
+        
+        Map<String, String> result = JoinerSplitter.arrayToMap(programming_languages);
+        assertEquals(result, expectation);
+        
+    }
 
 }

java-strings/src/test/java/com/baeldung/string/SplitUnitTest.java

@@ -2,10 +2,11 @@ package com.baeldung.string;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import java.util.Arrays;
 import java.util.List;
 
 import org.apache.commons.lang3.StringUtils;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 import com.google.common.base.Splitter;
 
@@ -54,4 +55,18 @@ public class SplitUnitTest {
         assertThat(resultList)
           .containsExactly("car", "jeep", "scooter");
     }
+    
+    @Test
+    public void givenStringContainsSpaces_whenSplitAndTrim_thenReturnsArray_using_Regex() {
+        assertThat(" car , jeep,  scooter ".trim()
+          .split("\\s*,\\s*")).containsExactly("car", "jeep", "scooter");
+
+    }
+    
+    @Test
+    public void givenStringContainsSpaces_whenSplitAndTrim_thenReturnsArray_using_java_8() {
+        assertThat(Arrays.stream(" car , jeep,  scooter ".split(","))
+          .map(String::trim)
+          .toArray(String[]::new)).containsExactly("car", "jeep", "scooter");
+    }   
 }

jersey/pom.xml

@@ -39,6 +39,11 @@
             <artifactId>jersey-mvc-freemarker</artifactId>
             <version>${jersey.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.glassfish.jersey.ext</groupId>
+            <artifactId>jersey-bean-validation</artifactId>
+            <version>${jersey.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.glassfish.jersey.test-framework</groupId>
             <artifactId>jersey-test-framework-core</artifactId>

jersey/src/main/java/com/baeldung/jersey/server/config/ViewApplicationConfig.java

@@ -1,12 +1,14 @@
 package com.baeldung.jersey.server.config;
 
 import org.glassfish.jersey.server.ResourceConfig;
+import org.glassfish.jersey.server.ServerProperties;
 import org.glassfish.jersey.server.mvc.freemarker.FreemarkerMvcFeature;
 
 public class ViewApplicationConfig extends ResourceConfig {
     
     public ViewApplicationConfig() {
         packages("com.baeldung.jersey.server");
+        property(ServerProperties.BV_SEND_ERROR_IN_RESPONSE, true);
         property(FreemarkerMvcFeature.TEMPLATE_BASE_PATH, "templates/freemarker");
         register(FreemarkerMvcFeature.class);;
     }

jersey/src/main/java/com/baeldung/jersey/server/constraints/SerialNumber.java

@@ -0,0 +1,35 @@
+package com.baeldung.jersey.server.constraints;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.regex.Pattern;
+
+import javax.validation.Constraint;
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+import javax.validation.Payload;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Constraint(validatedBy = { SerialNumber.Validator.class })
+public @interface SerialNumber {
+
+    String message()
+
+    default "Fruit serial number is not valid";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+
+    public class Validator implements ConstraintValidator<SerialNumber, String> {
+        @Override
+        public void initialize(final SerialNumber serial) {
+        }
+
+        @Override
+        public boolean isValid(final String serial, final ConstraintValidatorContext constraintValidatorContext) {
+            final String serialNumRegex = "^\\d{3}-\\d{3}-\\d{4}$";
+            return Pattern.matches(serialNumRegex, serial);
+        }
+    }
+}

jersey/src/main/java/com/baeldung/jersey/server/model/Fruit.java

@@ -1,20 +1,57 @@
 package com.baeldung.jersey.server.model;
 
+import javax.validation.constraints.Min;
+import javax.validation.constraints.Size;
+import javax.xml.bind.annotation.XmlRootElement;
+
+@XmlRootElement
 public class Fruit {
 
-    private final String name;
-    private final String colour;
+    @Min(value = 10, message = "Fruit weight must be 10 or greater")
+    private Integer weight;
+    @Size(min = 5, max = 200)
+    private String name;
+    @Size(min = 5, max = 200)
+    private String colour;
+    private String serial;
+
+    public Fruit() {
+    }
 
     public Fruit(String name, String colour) {
         this.name = name;
         this.colour = colour;
     }
-    
+
     public String getName() {
         return name;
     }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public void setColour(String colour) {
+        this.colour = colour;
+    }
 
     public String getColour() {
         return colour;
     }
+
+    public Integer getWeight() {
+        return weight;
+    }
+
+    public void setWeight(Integer weight) {
+        this.weight = weight;
+    }
+    
+    public String getSerial() {
+        return serial;
+    }
+
+    public void setSerial(String serial) {
+        this.serial = serial;
+    }
 }

jersey/src/main/java/com/baeldung/jersey/server/providers/FruitExceptionMapper.java

@@ -0,0 +1,26 @@
+package com.baeldung.jersey.server.providers;
+
+import javax.validation.ConstraintViolation;
+import javax.validation.ConstraintViolationException;
+import javax.ws.rs.core.Response;
+import javax.ws.rs.ext.ExceptionMapper;
+
+public class FruitExceptionMapper implements ExceptionMapper<ConstraintViolationException> {
+
+    @Override
+    public Response toResponse(final ConstraintViolationException exception) {
+        return Response.status(Response.Status.BAD_REQUEST)
+            .entity(prepareMessage(exception))
+            .type("text/plain")
+            .build();
+    }
+
+    private String prepareMessage(ConstraintViolationException exception) {
+        final StringBuilder message = new StringBuilder();
+        for (ConstraintViolation<?> cv : exception.getConstraintViolations()) {
+            message.append(cv.getPropertyPath() + " " + cv.getMessage() + "\n");
+        }
+        return message.toString();
+    }
+
+}

jersey/src/main/java/com/baeldung/jersey/server/rest/FruitResource.java

@@ -5,7 +5,13 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import javax.validation.Valid;
+import javax.validation.constraints.NotNull;
+import javax.ws.rs.Consumes;
+import javax.ws.rs.FormParam;
 import javax.ws.rs.GET;
+import javax.ws.rs.POST;
+import javax.ws.rs.PUT;
 import javax.ws.rs.Path;
 import javax.ws.rs.PathParam;
 import javax.ws.rs.Produces;
@@ -15,7 +21,9 @@ import org.glassfish.jersey.server.mvc.ErrorTemplate;
 import org.glassfish.jersey.server.mvc.Template;
 import org.glassfish.jersey.server.mvc.Viewable;
 
+import com.baeldung.jersey.server.constraints.SerialNumber;
 import com.baeldung.jersey.server.model.Fruit;
+import com.baeldung.jersey.service.SimpleStorageService;
 
 @Path("/fruit")
 public class FruitResource {
@@ -52,4 +60,49 @@ public class FruitResource {
         return name;
     }
 
+    @POST
+    @Path("/create")
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    public void createFruit(
+        @NotNull(message = "Fruit name must not be null") @FormParam("name") String name, 
+        @NotNull(message = "Fruit colour must not be null") @FormParam("colour") String colour) {
+
+        Fruit fruit = new Fruit(name, colour);
+        SimpleStorageService.storeFruit(fruit);
+    }
+    
+    @PUT
+    @Path("/update")
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    public void updateFruit(@SerialNumber @FormParam("serial") String serial) {
+        Fruit fruit = new Fruit();
+        fruit.setSerial(serial);
+        SimpleStorageService.storeFruit(fruit);
+    }
+
+    @POST
+    @Path("/create")
+    @Consumes(MediaType.APPLICATION_JSON)
+    public void createFruit(@Valid Fruit fruit) {
+        SimpleStorageService.storeFruit(fruit);
+    }
+
+    @GET
+    @Valid
+    @Produces(MediaType.APPLICATION_JSON)
+    @Path("/search/{name}")
+    public Fruit findFruitByName(@PathParam("name") String name) {
+        return SimpleStorageService.findByName(name);
+    }
+
+    @GET
+    @Produces(MediaType.TEXT_HTML)
+    @Path("/exception")
+    @Valid
+    public Fruit exception() {
+        Fruit fruit = new Fruit();
+        fruit.setName("a");
+        fruit.setColour("b");
+        return fruit;
+    }
 }

jersey/src/main/java/com/baeldung/jersey/service/SimpleStorageService.java

@@ -0,0 +1,25 @@
+package com.baeldung.jersey.service;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import com.baeldung.jersey.server.model.Fruit;
+
+public class SimpleStorageService {
+
+    private static final Map<String, Fruit> fruits = new HashMap<String, Fruit>();
+
+    public static void storeFruit(final Fruit fruit) {
+        fruits.put(fruit.getName(), fruit);
+    }
+    
+    public static Fruit findByName(final String name) {
+        return fruits.entrySet()
+            .stream()
+            .filter(map -> name.equals(map.getKey()))
+            .map(map -> map.getValue())
+            .findFirst()
+            .get();
+    }
+
+}

jersey/src/test/java/com/baeldung/jersey/server/rest/FruitResourceIntegrationTest.java

@@ -2,41 +2,116 @@ package com.baeldung.jersey.server.rest;
 
 import static org.hamcrest.CoreMatchers.allOf;
 import static org.hamcrest.CoreMatchers.containsString;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
 
+import javax.ws.rs.client.Entity;
 import javax.ws.rs.core.Application;
+import javax.ws.rs.core.Form;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
 
 import org.glassfish.jersey.test.JerseyTest;
-import org.junit.Assert;
+import org.glassfish.jersey.test.TestProperties;
 import org.junit.Test;
 
 import com.baeldung.jersey.server.config.ViewApplicationConfig;
+import com.baeldung.jersey.server.model.Fruit;
+import com.baeldung.jersey.server.providers.FruitExceptionMapper;
 
 public class FruitResourceIntegrationTest extends JerseyTest {
 
     @Override
     protected Application configure() {
-        return new ViewApplicationConfig();
+        enable(TestProperties.LOG_TRAFFIC);
+        enable(TestProperties.DUMP_ENTITY);
+
+        ViewApplicationConfig config = new ViewApplicationConfig();
+        config.register(FruitExceptionMapper.class);
+        return config;
     }
 
     @Test
-    public void testAllFruit() {
+    public void givenGetAllFruit_whenCorrectRequest_thenAllTemplateInvoked() {
         final String response = target("/fruit/all").request()
             .get(String.class);
-        Assert.assertThat(response, allOf(containsString("banana"), containsString("apple"), containsString("kiwi")));
+        assertThat(response, allOf(containsString("banana"), containsString("apple"), containsString("kiwi")));
     }
 
     @Test
-    public void testIndex() {
+    public void givenGetFruit_whenCorrectRequest_thenIndexTemplateInvoked() {
         final String response = target("/fruit").request()
             .get(String.class);
-        Assert.assertThat(response, containsString("Welcome Fruit Index Page!"));
+        assertThat(response, containsString("Welcome Fruit Index Page!"));
     }
 
     @Test
-    public void testErrorTemplate() {
+    public void givenGetFruitByName_whenFruitUnknown_thenErrorTemplateInvoked() {
         final String response = target("/fruit/orange").request()
             .get(String.class);
-        Assert.assertThat(response, containsString("Error -  Fruit not found: orange!"));
+        assertThat(response, containsString("Error -  Fruit not found: orange!"));
+    }
+
+    @Test
+    public void givenCreateFruit_whenFormContainsNullParam_thenResponseCodeIsBadRequest() {
+        Form form = new Form();
+        form.param("name", "apple");
+        form.param("colour", null);
+        Response response = target("fruit/create").request(MediaType.APPLICATION_FORM_URLENCODED)
+            .post(Entity.form(form));
+
+        assertEquals("Http Response should be 400 ", 400, response.getStatus());
+        assertThat(response.readEntity(String.class), containsString("Fruit colour must not be null"));
+    }
+
+    @Test
+    public void givenUpdateFruit_whenFormContainsBadSerialParam_thenResponseCodeIsBadRequest() {
+        Form form = new Form();
+        form.param("serial", "2345-2345");
+
+        Response response = target("fruit/update").request(MediaType.APPLICATION_FORM_URLENCODED)
+            .put(Entity.form(form));
+
+        assertEquals("Http Response should be 400 ", 400, response.getStatus());
+        assertThat(response.readEntity(String.class), containsString("Fruit serial number is not valid"));
+    }
+
+    @Test
+    public void givenCreateFruit_whenFruitIsInvalid_thenResponseCodeIsBadRequest() {
+        Fruit fruit = new Fruit("Blueberry", "purple");
+        fruit.setWeight(1);
+
+        Response response = target("fruit/create").request(MediaType.APPLICATION_JSON_TYPE)
+            .post(Entity.entity(fruit, MediaType.APPLICATION_JSON_TYPE));
+
+        assertEquals("Http Response should be 400 ", 400, response.getStatus());
+        assertThat(response.readEntity(String.class), containsString("Fruit weight must be 10 or greater"));
+    }
+
+    @Test
+    public void givenFruitExists_whenSearching_thenResponseContainsFruit() {
+        Fruit fruit = new Fruit();
+        fruit.setName("strawberry");
+        fruit.setWeight(20);
+        Response response = target("fruit/create").request(MediaType.APPLICATION_JSON_TYPE)
+            .post(Entity.entity(fruit, MediaType.APPLICATION_JSON_TYPE));
+
+        assertEquals("Http Response should be 204 ", 204, response.getStatus());
+
+        final String json = target("fruit/search/strawberry").request()
+            .get(String.class);
+        assertThat(json, containsString("{\"name\":\"strawberry\",\"weight\":20}"));
+    }
+
+    @Test
+    public void givenFruit_whenFruitIsInvalid_thenReponseContainsCustomExceptions() {
+        final Response response = target("fruit/exception").request()
+            .get();
+
+        assertEquals("Http Response should be 400 ", 400, response.getStatus());
+        String responseString = response.readEntity(String.class);
+        assertThat(responseString, containsString("exception.<return value>.colour size must be between 5 and 200"));
+        assertThat(responseString, containsString("exception.<return value>.name size must be between 5 and 200"));
     }
 
 }

jta/pom.xml

@@ -0,0 +1,88 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>jta-demo</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <description>JEE JTA demo</description>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>2.0.4.RELEASE</version>
+        <relativePath/>
+    </parent>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+        <java.version>1.8</java.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-jta-bitronix</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-jdbc</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.hsqldb</groupId>
+            <artifactId>hsqldb</artifactId>
+            <version>2.4.1</version>
+        </dependency>
+    </dependencies>
+
+    <profiles>
+        <profile>
+            <id>autoconfiguration</id>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-surefire-plugin</artifactId>
+                        <executions>
+                            <execution>
+                                <phase>integration-test</phase>
+                                <goals>
+                                    <goal>test</goal>
+                                </goals>
+                                <configuration>
+                                    <excludes>
+                                        <exclude>**/*LiveTest.java</exclude>
+                                        <exclude>**/*IntegrationTest.java</exclude>
+                                        <exclude>**/*IntTest.java</exclude>
+                                    </excludes>
+                                    <includes>
+                                        <include>**/AutoconfigurationTest.java</include>
+                                    </includes>
+                                </configuration>
+                            </execution>
+                        </executions>
+                        <configuration>
+                            <systemPropertyVariables>
+                                <test.mime>json</test.mime>
+                            </systemPropertyVariables>
+                        </configuration>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
+</project>

jta/src/main/java/com/baeldung/jtademo/JtaDemoApplication.java

@@ -0,0 +1,48 @@
+package com.baeldung.jtademo;
+
+import org.hsqldb.jdbc.pool.JDBCXADataSource;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.jta.bitronix.BitronixXADataSourceWrapper;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+
+import javax.sql.DataSource;
+
+@EnableAutoConfiguration
+@EnableTransactionManagement
+@Configuration
+@ComponentScan
+public class JtaDemoApplication {
+
+    @Bean("dataSourceAccount")
+    public DataSource dataSource() throws Exception {
+        return createHsqlXADatasource("jdbc:hsqldb:mem:accountDb");
+    }
+
+    @Bean("dataSourceAudit")
+    public DataSource dataSourceAudit() throws Exception {
+        return createHsqlXADatasource("jdbc:hsqldb:mem:auditDb");
+    }
+
+    private DataSource createHsqlXADatasource(String connectionUrl) throws Exception {
+        JDBCXADataSource dataSource = new JDBCXADataSource();
+        dataSource.setUrl(connectionUrl);
+        dataSource.setUser("sa");
+        BitronixXADataSourceWrapper wrapper = new BitronixXADataSourceWrapper();
+        return wrapper.wrapDataSource(dataSource);
+    }
+
+    @Bean("jdbcTemplateAccount")
+    public JdbcTemplate jdbcTemplate(@Qualifier("dataSourceAccount") DataSource dataSource) {
+        return new JdbcTemplate(dataSource);
+    }
+
+    @Bean("jdbcTemplateAudit")
+    public JdbcTemplate jdbcTemplateAudit(@Qualifier("dataSourceAudit") DataSource dataSource) {
+        return new JdbcTemplate(dataSource);
+    }
+}

jta/src/main/java/com/baeldung/jtademo/dto/TransferLog.java

@@ -0,0 +1,27 @@
+package com.baeldung.jtademo.dto;
+
+import java.math.BigDecimal;
+
+public class TransferLog {
+    private String fromAccountId;
+    private String toAccountId;
+    private BigDecimal amount;
+
+    public TransferLog(String fromAccountId, String toAccountId, BigDecimal amount) {
+        this.fromAccountId = fromAccountId;
+        this.toAccountId = toAccountId;
+        this.amount = amount;
+    }
+
+    public String getFromAccountId() {
+        return fromAccountId;
+    }
+
+    public String getToAccountId() {
+        return toAccountId;
+    }
+
+    public BigDecimal getAmount() {
+        return amount;
+    }
+}

jta/src/main/java/com/baeldung/jtademo/services/AuditService.java

@@ -0,0 +1,33 @@
+package com.baeldung.jtademo.services;
+
+import com.baeldung.jtademo.dto.TransferLog;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.core.ResultSetExtractor;
+import org.springframework.stereotype.Service;
+
+import java.math.BigDecimal;
+
+@Service
+public class AuditService {
+
+    final JdbcTemplate jdbcTemplate;
+
+    @Autowired
+    public AuditService(@Qualifier("jdbcTemplateAudit") JdbcTemplate jdbcTemplate) {
+        this.jdbcTemplate = jdbcTemplate;
+    }
+
+    public void log(String fromAccount, String toAccount, BigDecimal amount) {
+        jdbcTemplate.update("insert into AUDIT_LOG(FROM_ACCOUNT, TO_ACCOUNT, AMOUNT) values ?,?,?", fromAccount, toAccount, amount);
+    }
+
+    public TransferLog lastTransferLog() {
+        return jdbcTemplate.query("select FROM_ACCOUNT,TO_ACCOUNT,AMOUNT from AUDIT_LOG order by ID desc", (ResultSetExtractor<TransferLog>) (rs) -> {
+            if (!rs.next())
+                return null;
+            return new TransferLog(rs.getString(1), rs.getString(2), BigDecimal.valueOf(rs.getDouble(3)));
+        });
+    }
+}

jta/src/main/java/com/baeldung/jtademo/services/BankAccountService.java

@@ -0,0 +1,32 @@
+package com.baeldung.jtademo.services;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.core.ResultSetExtractor;
+import org.springframework.stereotype.Service;
+
+import java.math.BigDecimal;
+
+@Service
+public class BankAccountService {
+
+    final JdbcTemplate jdbcTemplate;
+
+    @Autowired
+    public BankAccountService(@Qualifier("jdbcTemplateAccount") JdbcTemplate jdbcTemplate) {
+        this.jdbcTemplate = jdbcTemplate;
+    }
+
+    public void transfer(String fromAccountId, String toAccountId, BigDecimal amount) {
+        jdbcTemplate.update("update ACCOUNT set BALANCE=BALANCE-? where ID=?", amount, fromAccountId);
+        jdbcTemplate.update("update ACCOUNT set BALANCE=BALANCE+? where ID=?", amount, toAccountId);
+    }
+
+    public BigDecimal balanceOf(String accountId) {
+        return jdbcTemplate.query("select BALANCE from ACCOUNT where ID=?", new Object[] { accountId }, (ResultSetExtractor<BigDecimal>) (rs) -> {
+            rs.next();
+            return new BigDecimal(rs.getDouble(1));
+        });
+    }
+}

jta/src/main/java/com/baeldung/jtademo/services/TellerService.java

@@ -0,0 +1,45 @@
+package com.baeldung.jtademo.services;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import javax.transaction.Transactional;
+import javax.transaction.UserTransaction;
+import java.math.BigDecimal;
+
+@Service
+public class TellerService {
+    private final BankAccountService bankAccountService;
+    private final AuditService auditService;
+    private final UserTransaction userTransaction;
+
+    @Autowired
+    public TellerService(BankAccountService bankAccountService, AuditService auditService, UserTransaction userTransaction) {
+        this.bankAccountService = bankAccountService;
+        this.auditService = auditService;
+        this.userTransaction = userTransaction;
+    }
+
+    @Transactional
+    public void executeTransfer(String fromAccontId, String toAccountId, BigDecimal amount) {
+        bankAccountService.transfer(fromAccontId, toAccountId, amount);
+        auditService.log(fromAccontId, toAccountId, amount);
+        BigDecimal balance = bankAccountService.balanceOf(fromAccontId);
+        if (balance.compareTo(BigDecimal.ZERO) <= 0) {
+            throw new RuntimeException("Insufficient fund.");
+        }
+    }
+
+    public void executeTransferProgrammaticTx(String fromAccontId, String toAccountId, BigDecimal amount) throws Exception {
+        userTransaction.begin();
+        bankAccountService.transfer(fromAccontId, toAccountId, amount);
+        auditService.log(fromAccontId, toAccountId, amount);
+        BigDecimal balance = bankAccountService.balanceOf(fromAccontId);
+        if (balance.compareTo(BigDecimal.ZERO) <= 0) {
+            userTransaction.rollback();
+            throw new RuntimeException("Insufficient fund.");
+        } else {
+            userTransaction.commit();
+        }
+    }
+}

jta/src/main/java/com/baeldung/jtademo/services/TestHelper.java

@@ -0,0 +1,43 @@
+package com.baeldung.jtademo.services;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.core.io.DefaultResourceLoader;
+import org.springframework.core.io.Resource;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.datasource.init.ScriptUtils;
+import org.springframework.stereotype.Component;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.SQLException;
+
+@Component
+public class TestHelper {
+    final JdbcTemplate jdbcTemplateAccount;
+
+    final JdbcTemplate jdbcTemplateAudit;
+
+    @Autowired
+    public TestHelper(@Qualifier("jdbcTemplateAccount") JdbcTemplate jdbcTemplateAccount, @Qualifier("jdbcTemplateAudit") JdbcTemplate jdbcTemplateAudit) {
+        this.jdbcTemplateAccount = jdbcTemplateAccount;
+        this.jdbcTemplateAudit = jdbcTemplateAudit;
+    }
+
+    public void runAccountDbInit() throws SQLException {
+        runScript("account.sql", jdbcTemplateAccount.getDataSource());
+    }
+
+    public void runAuditDbInit() throws SQLException {
+        runScript("audit.sql", jdbcTemplateAudit.getDataSource());
+    }
+
+    private void runScript(String scriptName, DataSource dataSouorce) throws SQLException {
+        DefaultResourceLoader resourceLoader = new DefaultResourceLoader();
+        Resource script = resourceLoader.getResource(scriptName);
+        try (Connection con = dataSouorce.getConnection()) {
+            ScriptUtils.executeSqlScript(con, script);
+        }
+    }
+
+}

jta/src/main/resources/account.sql

@@ -0,0 +1,9 @@
+DROP SCHEMA PUBLIC CASCADE;
+
+create table ACCOUNT (
+ID char(8) PRIMARY KEY,
+BALANCE NUMERIC(28,10)
+);
+
+insert into ACCOUNT(ID, BALANCE) values ('a0000001', 1000);
+insert into ACCOUNT(ID, BALANCE) values ('a0000002', 2000);

jta/src/main/resources/audit.sql

@@ -0,0 +1,8 @@
+DROP SCHEMA PUBLIC CASCADE;
+
+create table AUDIT_LOG (
+ID INTEGER IDENTITY PRIMARY KEY,
+FROM_ACCOUNT varchar(8),
+TO_ACCOUNT varchar(8),
+AMOUNT numeric(28,10)
+);

jta/src/test/java/com/baeldung/jtademo/JtaDemoUnitTest.java

@@ -0,0 +1,91 @@
+package com.baeldung.jtademo;
+
+import com.baeldung.jtademo.dto.TransferLog;
+import com.baeldung.jtademo.services.AuditService;
+import com.baeldung.jtademo.services.BankAccountService;
+import com.baeldung.jtademo.services.TellerService;
+import com.baeldung.jtademo.services.TestHelper;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.math.BigDecimal;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = JtaDemoApplication.class)
+public class JtaDemoUnitTest {
+    @Autowired
+    TestHelper testHelper;
+
+    @Autowired
+    TellerService tellerService;
+
+    @Autowired
+    BankAccountService accountService;
+
+    @Autowired
+    AuditService auditService;
+
+    @Before
+    public void beforeTest() throws Exception {
+        testHelper.runAuditDbInit();
+        testHelper.runAccountDbInit();
+    }
+
+    @Test
+    public void givenAnnotationTx_whenNoException_thenAllCommitted() throws Exception {
+        tellerService.executeTransfer("a0000001", "a0000002", BigDecimal.valueOf(500));
+
+        assertThat(accountService.balanceOf("a0000001")).isEqualByComparingTo(BigDecimal.valueOf(500));
+        assertThat(accountService.balanceOf("a0000002")).isEqualByComparingTo(BigDecimal.valueOf(2500));
+
+        TransferLog lastTransferLog = auditService.lastTransferLog();
+        assertThat(lastTransferLog).isNotNull();
+        assertThat(lastTransferLog.getFromAccountId()).isEqualTo("a0000001");
+        assertThat(lastTransferLog.getToAccountId()).isEqualTo("a0000002");
+        assertThat(lastTransferLog.getAmount()).isEqualByComparingTo(BigDecimal.valueOf(500));
+    }
+
+    @Test
+    public void givenAnnotationTx_whenException_thenAllRolledBack() throws Exception {
+        assertThatThrownBy(() -> {
+            tellerService.executeTransfer("a0000002", "a0000001", BigDecimal.valueOf(100000));
+        }).hasMessage("Insufficient fund.");
+
+        assertThat(accountService.balanceOf("a0000001")).isEqualByComparingTo(BigDecimal.valueOf(1000));
+        assertThat(accountService.balanceOf("a0000002")).isEqualByComparingTo(BigDecimal.valueOf(2000));
+        assertThat(auditService.lastTransferLog()).isNull();
+    }
+
+    @Test
+    public void givenProgrammaticTx_whenCommit_thenAllCommitted() throws Exception {
+        tellerService.executeTransferProgrammaticTx("a0000001", "a0000002", BigDecimal.valueOf(500));
+
+        BigDecimal result = accountService.balanceOf("a0000001");
+        assertThat(accountService.balanceOf("a0000001")).isEqualByComparingTo(BigDecimal.valueOf(500));
+        assertThat(accountService.balanceOf("a0000002")).isEqualByComparingTo(BigDecimal.valueOf(2500));
+
+        TransferLog lastTransferLog = auditService.lastTransferLog();
+        assertThat(lastTransferLog).isNotNull();
+        assertThat(lastTransferLog.getFromAccountId()).isEqualTo("a0000001");
+        assertThat(lastTransferLog.getToAccountId()).isEqualTo("a0000002");
+        assertThat(lastTransferLog.getAmount()).isEqualByComparingTo(BigDecimal.valueOf(500));
+    }
+
+    @Test
+    public void givenProgrammaticTx_whenRollback_thenAllRolledBack() throws Exception {
+        assertThatThrownBy(() -> {
+            tellerService.executeTransferProgrammaticTx("a0000002", "a0000001", BigDecimal.valueOf(100000));
+        }).hasMessage("Insufficient fund.");
+
+        assertThat(accountService.balanceOf("a0000001")).isEqualByComparingTo(BigDecimal.valueOf(1000));
+        assertThat(accountService.balanceOf("a0000002")).isEqualByComparingTo(BigDecimal.valueOf(2000));
+        assertThat(auditService.lastTransferLog()).isNull();
+    }
+}

kotlin-libraries/README.md

@@ -0,0 +1,10 @@
+## Relevant articles:
+
+- [Kotlin with Mockito](http://www.baeldung.com/kotlin-mockito)
+- [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)
+- [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 with Ktor](http://www.baeldung.com/kotlin-ktor)
+- [Idiomatic Logging in Kotlin](http://www.baeldung.com/kotlin-logging)
+- [Guide to the Kotlin Exposed Framework](https://www.baeldung.com/kotlin-exposed-persistence)

kotlin-libraries/build.gradle

@@ -1,47 +1,57 @@
-
-
-group 'com.baeldung.ktor'
-version '1.0-SNAPSHOT'
-
-
-buildscript {
-    ext.kotlin_version = '1.2.41'
-    ext.ktor_version = '0.9.2'
-
-    repositories {
-        mavenCentral()
-    }
-    dependencies {
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-    }
-}
-
-apply plugin: 'java'
-apply plugin: 'kotlin'
-apply plugin: 'application'
-
-mainClassName = 'APIServer.kt'
-
-sourceCompatibility = 1.8
-compileKotlin { kotlinOptions.jvmTarget = "1.8" }
-compileTestKotlin { kotlinOptions.jvmTarget = "1.8" }
-
-kotlin { experimental { coroutines "enable" } }
-
-repositories {
-    mavenCentral()
-    jcenter()
-    maven { url "https://dl.bintray.com/kotlin/ktor" }
-}
-
-dependencies {
-    compile "io.ktor:ktor-server-netty:$ktor_version"
-    compile "ch.qos.logback:logback-classic:1.2.1"
-    compile "io.ktor:ktor-gson:$ktor_version"
-    testCompile group: 'junit', name: 'junit', version: '4.12'
-
-}
-task runServer(type: JavaExec) {
-    main = 'APIServer'
-    classpath = sourceSets.main.runtimeClasspath
+
+
+group 'com.baeldung.ktor'
+version '1.0-SNAPSHOT'
+
+
+buildscript {
+    ext.kotlin_version = '1.2.41'
+    ext.ktor_version = '0.9.2'
+
+    repositories {
+        mavenCentral()
+    }
+    dependencies {
+
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+apply plugin: 'java'
+apply plugin: 'kotlin'
+apply plugin: 'application'
+
+mainClassName = 'APIServer.kt'
+
+sourceCompatibility = 1.8
+compileKotlin { kotlinOptions.jvmTarget = "1.8" }
+compileTestKotlin { kotlinOptions.jvmTarget = "1.8" }
+
+kotlin { experimental { coroutines "enable" } }
+
+repositories {
+    mavenCentral()
+    jcenter()
+    maven { url "https://dl.bintray.com/kotlin/ktor" }
+}
+sourceSets {
+    main{
+        kotlin{
+            srcDirs 'com/baeldung/ktor'
+        }
+    }
+
+}
+
+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
 }

kotlin-libraries/gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
-distributionBase=GRADLE_USER_HOME
-distributionPath=wrapper/dists
-zipStoreBase=GRADLE_USER_HOME
-zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-bin.zip
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-bin.zip

kotlin-libraries/gradlew.bat

@@ -1,84 +1,84 @@
-@if "%DEBUG%" == "" @echo off
-@rem ##########################################################################
-@rem
-@rem  Gradle startup script for Windows
-@rem
-@rem ##########################################################################
-
-@rem Set local scope for the variables with windows NT shell
-if "%OS%"=="Windows_NT" setlocal
-
-set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
-set APP_BASE_NAME=%~n0
-set APP_HOME=%DIRNAME%
-
-@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=
-
-@rem Find java.exe
-if defined JAVA_HOME goto findJavaFromJavaHome
-
-set JAVA_EXE=java.exe
-%JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
-
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
-
-goto fail
-
-:findJavaFromJavaHome
-set JAVA_HOME=%JAVA_HOME:"=%
-set JAVA_EXE=%JAVA_HOME%/bin/java.exe
-
-if exist "%JAVA_EXE%" goto init
-
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
-
-goto fail
-
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-
-:execute
-@rem Setup the command line
-
-set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
-
-@rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
-
-:end
-@rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
-
-:fail
-rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
-rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
-
-:mainEnd
-if "%OS%"=="Windows_NT" endlocal
-
-:omega
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

kotlin-libraries/pom.xml

@@ -0,0 +1,105 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>kotlin-libraries</artifactId>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-kotlin</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <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>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${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>
+    </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>
+    </properties>
+
+</project>

kotlin-libraries/resources/logback.xml

@@ -1,11 +1,11 @@
-<configuration>
-  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-    <encoder>
-      <pattern>%d{YYYY-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
-    </encoder>
-  </appender>
-
-  <root level="INFO">
-    <appender-ref ref="STDOUT"/>
-  </root>
+<configuration>
+  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+    <encoder>
+      <pattern>%d{YYYY-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+    </encoder>
+  </appender>
+
+  <root level="INFO">
+    <appender-ref ref="STDOUT"/>
+  </root>
 </configuration>

kotlin-libraries/settings.gradle

@@ -1,2 +1,2 @@
-rootProject.name = 'KtorWithKotlin'
-
+rootProject.name = 'KtorWithKotlin'
+

kotlin-libraries/src/test/kotlin/com/baeldung/kotlin/junit5/Calculator.kt

@@ -0,0 +1,17 @@
+package com.baeldung.kotlin.junit5
+
+class Calculator {
+    fun add(a: Int, b: Int) = a + b
+
+    fun divide(a: Int, b: Int) = if (b == 0) {
+        throw DivideByZeroException(a)
+    } else {
+        a / b
+    }
+
+    fun square(a: Int) = a * a
+
+    fun squareRoot(a: Int) = Math.sqrt(a.toDouble())
+
+    fun log(base: Int, value: Int) = Math.log(value.toDouble()) / Math.log(base.toDouble())
+}

kotlin-libraries/src/test/kotlin/com/baeldung/kotlin/junit5/DivideByZeroException.kt

@@ -0,0 +1,3 @@
+package com.baeldung.kotlin.junit5
+
+class DivideByZeroException(val numerator: Int) : Exception()