Merge remote-tracking branch 'eugenp/master'

algorithms/src/main/java/com/baeldung/algorithms/linesintersection/LinesIntersectionService.java

@@ -0,0 +1,21 @@
+package com.baeldung.algorithms.linesintersection;
+
+import java.awt.Point;
+import java.util.Optional;
+
+public class LinesIntersectionService {
+
+    public Optional<Point> calculateIntersectionPoint(double m1, double b1, double m2, double b2) {
+
+        if (m1 == m2) {
+            return Optional.empty();
+        }
+
+        double x = (b2 - b1) / (m1 - m2);
+        double y = m1 * x + b1;
+
+        Point point = new Point();
+        point.setLocation(x, y);
+        return Optional.of(point);
+    }
+}

algorithms/src/test/java/com/baeldung/algorithms/linesintersection/LinesIntersectionServiceUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.linesintersection;
+package com.baeldung.algorithms.linesintersection;
 
 import java.awt.Point;
 import java.util.Optional;
@@ -14,24 +14,24 @@ public class LinesIntersectionServiceUnitTest {
     @Test
     public void givenNotParallelLines_whenCalculatePoint_thenPresent() {
 
-        float m1 = 0;
+        double m1 = 0;
-        float b1 = 0;
+        double b1 = 0;
-        float m2 = 1;
+        double m2 = 1;
-        float b2 = -1;
+        double b2 = -1;
 
         Optional<Point> point = service.calculateIntersectionPoint(m1, b1, m2, b2);
 
         assertTrue(point.isPresent());
-        assertEquals(point.get().x, 1);
+        assertEquals(point.get().getX(), 1, 0.001);
-        assertEquals(point.get().y, 0);
+        assertEquals(point.get().getY(), 0, 0.001);
     }
 
     @Test
     public void givenParallelLines_whenCalculatePoint_thenEmpty() {
-        float m1 = 1;
+        double m1 = 1;
-        float b1 = 0;
+        double b1 = 0;
-        float m2 = 1;
+        double m2 = 1;
-        float b2 = -1;
+        double b2 = -1;
 
         Optional<Point> point = service.calculateIntersectionPoint(m1, b1, m2, b2);
 

cdi/src/test/java/com/baeldung/test/dependencyinjection/ImageProcessorUnitTest.java

@@ -1,70 +1,91 @@
 package com.baeldung.test.dependencyinjection;
 
-import com.baeldung.dependencyinjection.imagefileeditors.GifFileEditor;
-import com.baeldung.dependencyinjection.imagefileeditors.JpgFileEditor;
-import com.baeldung.dependencyinjection.imagefileeditors.PngFileEditor;
-import com.baeldung.dependencyinjection.imageprocessors.ImageFileProcessor;
-import com.baeldung.dependencyinjection.loggers.TimeLogger;
-import java.text.SimpleDateFormat;
-import java.util.Calendar;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.within;
+
+import java.text.ParseException;
+import java.time.LocalTime;
+import java.time.temporal.ChronoUnit;
+
 import org.jboss.weld.environment.se.Weld;
 import org.jboss.weld.environment.se.WeldContainer;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
+import com.baeldung.dependencyinjection.imagefileeditors.PngFileEditor;
+import com.baeldung.dependencyinjection.imageprocessors.ImageFileProcessor;
+import com.baeldung.dependencyinjection.loggers.TimeLogger;
+
 public class ImageProcessorUnitTest {
-    
+
     private static ImageFileProcessor imageFileProcessor;
-    private static SimpleDateFormat dateFormat;
+
-    private static Calendar calendar;
-    
-    
     @BeforeClass
     public static void setImageProcessorInstance() {
         Weld weld = new Weld();
         WeldContainer container = weld.initialize();
-        imageFileProcessor = container.select(ImageFileProcessor.class).get();
+        imageFileProcessor = container.select(ImageFileProcessor.class)
+            .get();
         container.shutdown();
     }
-    
+
-    @BeforeClass
-    public static void setSimpleDateFormatInstance() {
-        dateFormat = new SimpleDateFormat("HH:mm");
-    }
-    
-    @BeforeClass
-    public static void setCalendarInstance() {
-        calendar = Calendar.getInstance();
-    }
-    
     @Test
     public void givenImageProcessorInstance_whenInjectedPngFileEditorandTimeLoggerInstances_thenTwoAssertions() {
         assertThat(imageFileProcessor.getImageFileditor()).isInstanceOf(PngFileEditor.class);
         assertThat(imageFileProcessor.getTimeLogger()).isInstanceOf(TimeLogger.class);
     }
-    
+
     @Test
-    public void givenImageProcessorInstance_whenCalledopenFile_thenOneAssertion() {
+    public void givenImageProcessorInstance_whenCalledopenFile_thenOneAssertion() throws ParseException {
-        String currentTime = dateFormat.format(calendar.getTime());
+        LocalTime currentTime = LocalTime.now();
-        assertThat(imageFileProcessor.openFile("file1.png")).isEqualTo("Opening PNG file file1.png at: " + currentTime);
+
+        String openFileLog = imageFileProcessor.openFile("file1.png");
+        assertThat(openFileLog).contains("Opening PNG file file1.png at: ");
+
+        LocalTime loggedTime = getLoggedTime(openFileLog);
+        assertThat(loggedTime).isCloseTo(currentTime, within(2, ChronoUnit.MINUTES));
     }
-    
+
     @Test
-    public void givenImageProcessorInstance_whenCallededitFile_thenOneAssertion() {
+    public void givenImageProcessorInstance_whenCallededitFile_thenOneAssertion() throws ParseException {
-        String currentTime = dateFormat.format(calendar.getTime());
+        LocalTime currentTime = LocalTime.now();
-        assertThat(imageFileProcessor.editFile("file1.png")).isEqualTo("Editing PNG file file1.png at: " + currentTime);
+
+        String editFileLog = imageFileProcessor.editFile("file1.png");
+        assertThat(editFileLog).contains("Editing PNG file file1.png at: ");
+
+        LocalTime loggedTime = getLoggedTime(editFileLog);
+        assertThat(loggedTime).isCloseTo(currentTime, within(2, ChronoUnit.MINUTES));
     }
-    
+
     @Test
-    public void givenImageProcessorInstance_whenCalledwriteFile_thenOneAssertion() {
+    public void givenImageProcessorInstance_whenCalledwriteFile_thenOneAssertion() throws ParseException {
-        String currentTime = dateFormat.format(calendar.getTime());
+        LocalTime currentTime = LocalTime.now();
-        assertThat(imageFileProcessor.writeFile("file1.png")).isEqualTo("Writing PNG file file1.png at: " + currentTime);
+
+        String writeFileLog = imageFileProcessor.writeFile("file1.png");
+        assertThat(writeFileLog).contains("Writing PNG file file1.png at: ");
+
+        LocalTime loggedTime = getLoggedTime(writeFileLog);
+        assertThat(loggedTime).isCloseTo(currentTime, within(2, ChronoUnit.MINUTES));
     }
-    
+
     @Test
-    public void givenImageProcessorInstance_whenCalledsaveFile_thenOneAssertion() {
+    public void givenImageProcessorInstance_whenCalledsaveFile_thenOneAssertion() throws ParseException {
-        String currentTime = dateFormat.format(calendar.getTime());
+        LocalTime currentTime = LocalTime.now();
-        assertThat(imageFileProcessor.saveFile("file1.png")).isEqualTo("Saving PNG file file1.png at: " + currentTime);
+
+        String saveFileLog = imageFileProcessor.saveFile("file1.png");
+        assertThat(saveFileLog).contains("Saving PNG file file1.png at: ");
+
+        LocalTime loggedTime = getLoggedTime(saveFileLog);
+        assertThat(loggedTime).isCloseTo(currentTime, within(2, ChronoUnit.MINUTES));
+    }
+
+    private LocalTime getLoggedTime(String log) throws ParseException {
+        String logTimeString = log.split("at: ")[1];
+
+        int hour = Integer.valueOf(logTimeString.split(":")[0]);
+        int minutes = Integer.valueOf(logTimeString.split(":")[1]);
+
+        LocalTime loggedTime = LocalTime.of(hour, minutes);
+        return loggedTime;
     }
 }

core-java-8/README.md

@@ -15,24 +15,17 @@
 - [Guide to Java 8 Comparator.comparing()](http://www.baeldung.com/java-8-comparator-comparing)
 - [Guide To Java 8 Optional](http://www.baeldung.com/java-optional)
 - [Guide to the Java 8 forEach](http://www.baeldung.com/foreach-java)
-- [Finding Max/Min of a List or Collection](http://www.baeldung.com/java-collection-min-max)
 - [Java Base64 Encoding and Decoding](http://www.baeldung.com/java-base64-encode-and-decode)
 - [The Difference Between map() and flatMap()](http://www.baeldung.com/java-difference-map-and-flatmap)
-- [Copy a File with Java](http://www.baeldung.com/java-copy-file)
 - [Static and Default Methods in Interfaces in Java](http://www.baeldung.com/java-static-default-methods)
 - [Efficient Word Frequency Calculator in Java](http://www.baeldung.com/java-word-frequency)
-- [Fail-Safe Iterator vs Fail-Fast Iterator](http://www.baeldung.com/java-fail-safe-vs-fail-fast-iterator)
-- [Shuffling Collections In Java](http://www.baeldung.com/java-shuffle-collection)
 - [Introduction to Spliterator in Java](http://www.baeldung.com/java-spliterator)
 - [Java 8 Math New Methods](http://www.baeldung.com/java-8-math)
 - [Overview of Java Built-in Annotations](http://www.baeldung.com/java-default-annotations)
 - [Finding Min/Max in an Array with Java](http://www.baeldung.com/java-array-min-max)
 - [Internationalization and Localization in Java 8](http://www.baeldung.com/java-8-localization)
-- [How to Find an Element in a List with Java](http://www.baeldung.com/find-list-element-java)
 - [Java Optional – orElse() vs orElseGet()](http://www.baeldung.com/java-optional-or-else-vs-or-else-get)
-- [An Introduction to Java.util.Hashtable Class](http://www.baeldung.com/java-hash-table)
 - [Method Parameter Reflection in Java](http://www.baeldung.com/java-parameter-reflection)
 - [Java 8 Unsigned Arithmetic Support](http://www.baeldung.com/java-unsigned-arithmetic)
 - [Generalized Target-Type Inference in Java](http://www.baeldung.com/java-generalized-target-type-inference)
-- [Copy a List to Another List in Java](http://www.baeldung.com/java-copy-list-to-another)
 - [Overriding System Time for Testing in Java](http://www.baeldung.com/java-override-system-time)

core-java-8/src/test/java/com/baeldung/nullsafecollectionstreams/NullSafeCollectionStreamsUsingJava8OptionalContainerUnitTest.java

@@ -5,25 +5,22 @@
  */
 package com.baeldung.nullsafecollectionstreams;
 
+import static org.junit.Assert.assertEquals;
+
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.stream.Stream;
-import org.junit.After;
+
-import org.junit.AfterClass;
-import org.junit.Before;
-import org.junit.BeforeClass;
 import org.junit.Test;
-import static org.junit.Assert.*;
 
 /**
  *
  * @author Kwaje Anthony <kwajeanthony@gmail.com>
  */
 public class NullSafeCollectionStreamsUsingJava8OptionalContainerUnitTest {
-    
+
-    private final NullSafeCollectionStreamsUsingJava8OptionalContainer instance = 
+    private final NullSafeCollectionStreamsUsingJava8OptionalContainer instance = new NullSafeCollectionStreamsUsingJava8OptionalContainer();
-            new NullSafeCollectionStreamsUsingJava8OptionalContainer();
 
     @Test
     public void whenCollectionIsNull_thenExpectAnEmptyStream() {
@@ -49,5 +46,5 @@ public class NullSafeCollectionStreamsUsingJava8OptionalContainerUnitTest {
             assertEquals(iter1.next(), iter2.next());
         assert !iter1.hasNext() && !iter2.hasNext();
     }
-    
+
 }

core-java-8/src/test/java/com/baeldung/streamordering/BenchmarkUnitTest.java

@@ -1,97 +0,0 @@
-package com.baeldung.streamordering;
-
-import org.junit.Test;
-import org.openjdk.jmh.annotations.*;
-import org.openjdk.jmh.infra.Blackhole;
-import org.openjdk.jmh.runner.Runner;
-import org.openjdk.jmh.runner.options.Options;
-import org.openjdk.jmh.runner.options.OptionsBuilder;
-import org.openjdk.jmh.runner.options.TimeValue;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Random;
-import java.util.concurrent.TimeUnit;
-import java.util.stream.IntStream;
-
-
-public class BenchmarkUnitTest
-{
-
-  @Test
-  public void
-  launchBenchmark() throws Exception {
-
-    Options opt = new OptionsBuilder()
-      // Specify which benchmarks to run.
-      // You can be more specific if you'd like to run only one benchmark per test.
-      .include(this.getClass().getName() + ".*")
-      // Set the following options as needed
-      .mode (Mode.AverageTime)
-      .timeUnit(TimeUnit.MICROSECONDS)
-      .warmupTime(TimeValue.seconds(1))
-      .warmupIterations(2)
-      .measurementTime(TimeValue.seconds(1))
-      .measurementIterations(2)
-      .threads(2)
-      .forks(1)
-      .shouldFailOnError(true)
-      .shouldDoGC(true)
-      //.jvmArgs("-XX:+UnlockDiagnosticVMOptions", "-XX:+PrintInlining")
-      //.addProfiler(WinPerfAsmProfiler.class)
-      .build();
-
-    new Runner(opt).run();
-
-
-  }
-
-  @Benchmark
-  public void givenOrderedStreamInput_whenStreamFiltered_showOpsPerMS(){
-    IntStream.range(1, 100_000_000).parallel().filter(i -> i % 10 == 0).toArray();
-  }
-
-  @Benchmark
-  public void givenUnorderedStreamInput_whenStreamFiltered_showOpsPerMS(){
-    IntStream.range(1,100_000_000).unordered().parallel().filter(i -> i % 10 == 0).toArray();
-  }
-
-  @Benchmark
-  public void givenUnorderedStreamInput_whenStreamDistinct_showOpsPerMS(){
-    IntStream.range(1, 1_000_000).unordered().parallel().distinct().toArray();
-  }
-
-  @Benchmark
-  public void givenOrderedStreamInput_whenStreamDistinct_showOpsPerMS() {
-    //section 5.1.
-    IntStream.range(1, 1_000_000).parallel().distinct().toArray();
-  }
-
-
-  // The JMH samples are the best documentation for how to use it
-  // http://hg.openjdk.java.net/code-tools/jmh/file/tip/jmh-samples/src/main/java/org/openjdk/jmh/samples/
-  @State(Scope.Thread)
-  public static class BenchmarkState
-  {
-    List<Integer> list;
-
-    @Setup(Level.Trial) public void
-    initialize() {
-
-      Random rand = new Random();
-
-      list = new ArrayList<>();
-      for (int i = 0; i < 1000; i++)
-        list.add (rand.nextInt());
-    }
-  }
-
-  @Benchmark public void
-  benchmark1 (BenchmarkState state, Blackhole bh) {
-
-    List<Integer> list = state.list;
-
-    for (int i = 0; i < 1000; i++)
-      bh.consume (list.get (i));
-  }
-}

core-java-8/src/test/java/com/baeldung/streamordering/StreamsOrderingUnitTest.java

@@ -1,149 +0,0 @@
-package com.baeldung.streamordering;
-
-import org.junit.Before;
-import org.junit.Test;
-
-import java.util.*;
-import java.util.function.Function;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-import java.util.stream.Collectors;
-import java.util.stream.IntStream;
-
-import static org.junit.Assert.assertEquals;
-
-public class StreamsOrderingUnitTest {
-
-  Logger logger = Logger.getLogger( StreamsOrderingUnitTest.class.getName());
-
-  @Before
-  public void setUp() throws Exception {
-    logger.setLevel(Level.ALL);
-  }
-
-  @Test
-  public void givenTwoCollections_whenStreamed_thenCheckOutputDifferent(){
-
-    List<String> list = Arrays.asList("B", "A", "C", "D", "F");
-    Set<String> set = new TreeSet<>(Arrays.asList("B", "A", "C", "D", "F"));
-
-    Object[] listOutput = list.stream().toArray();
-    Object[] setOutput = set.stream().toArray();
-
-    assertEquals("[B, A, C, D, F]", Arrays.toString(listOutput));
-    assertEquals("[A, B, C, D, F]", Arrays.toString(setOutput));
-
-  }
-
-  @Test
-  public void givenTwoCollections_whenStreamedInParallel_thenCheckOutputDifferent(){
-
-    List<String> list = Arrays.asList("B", "A", "C", "D", "F");
-    Set<String> set = new TreeSet<>(Arrays.asList("B", "A", "C", "D", "F"));
-
-    Object[] listOutput = list.stream().parallel().toArray();
-    Object[] setOutput = set.stream().parallel().toArray();
-
-    assertEquals("[B, A, C, D, F]", Arrays.toString(listOutput));
-    assertEquals("[A, B, C, D, F]", Arrays.toString(setOutput));
-
-  }
-
-
-
-  @Test
-  public void givenOrderedInput_whenUnorderedAndOrderedCompared_thenCheckUnorderedOutputChanges(){
-    Set<Integer> set = new TreeSet<>(
-      Arrays.asList(-9, -5, -4, -2, 1, 2, 4, 5, 7, 9, 12, 13, 16, 29, 23, 34, 57, 68, 90, 102, 230));
-
-      Object[] orderedArray = set.stream()
-        .parallel()
-        .limit(5)
-        .toArray();
-      Object[] unorderedArray = set.stream()
-        .unordered()
-        .parallel()
-        .limit(5)
-        .toArray();
-
-     logger.info(Arrays.toString(orderedArray));
-     logger.info(Arrays.toString(unorderedArray));
-  }
-
-
-  @Test
-  public void givenUnsortedStreamInput_whenStreamSorted_thenCheckOrderChanged(){
-
-    List<Integer> list = Arrays.asList(-3,10,-4,1,3);
-
-    Object[] listOutput = list.stream().toArray();
-    Object[] listOutputSorted = list.stream().sorted().toArray();
-
-    assertEquals("[-3, 10, -4, 1, 3]", Arrays.toString(listOutput));
-    assertEquals("[-4, -3, 1, 3, 10]", Arrays.toString(listOutputSorted));
-
-  }
-
-  @Test
-  public void givenUnsortedStreamInput_whenStreamDistinct_thenShowTimeTaken(){
-    long start, end;
-    start = System.currentTimeMillis();
-    IntStream.range(1,1_000_000).unordered().parallel().distinct().toArray();
-    end = System.currentTimeMillis();
-    System.out.println(String.format("Time taken when unordered: %d ms", (end - start)));
-  }
-
-
-  @Test
-  public void givenSameCollection_whenStreamTerminated_thenCheckEachVsEachOrdered(){
-
-    List<String> list = Arrays.asList("B", "A", "C", "D", "F");
-
-    list.stream().parallel().forEach(e -> logger.log(Level.INFO, e));
-    list.stream().parallel().forEachOrdered(e -> logger.log(Level.INFO, e));
-
-  }
-
-  @Test
-  public void givenSameCollection_whenStreamCollected_thenCheckOutput(){
-
-    List<String> list = Arrays.asList("B", "A", "C", "D", "F");
-
-    List<String> collectionList = list.stream().parallel().collect(Collectors.toList());
-    Set<String> collectionSet = list.stream().parallel().collect(Collectors.toCollection(TreeSet::new));
-
-    assertEquals("[B, A, C, D, F]", collectionList.toString());
-    assertEquals("[A, B, C, D, F]", collectionSet.toString());
-
-  }
-
-
-  @Test
-  public void givenListIterationOrder_whenStreamCollectedToMap_thenCeckOrderChanged() {
-    List<String> list = Arrays.asList("A", "BB", "CCC");
-
-    Map<String, Integer> hashMap = list.stream().collect(Collectors.toMap(Function.identity(), String::length));
-
-    Object[] keySet = hashMap.keySet().toArray();
-
-    assertEquals("[BB, A, CCC]", Arrays.toString(keySet));
-
-  }
-
-  @Test
-  public void givenListIteration_whenStreamCollectedtoHashMap_thenCheckOrderMaintained() {
-    List<String> list = Arrays.asList("A", "BB", "CCC", "CCC");
-
-    Map<String, Integer> linkedHashMap = list.stream().collect(Collectors.toMap(
-      Function.identity(),
-      String::length,
-      (u, v) -> u,
-      LinkedHashMap::new
-    ));
-
-    Object[] keySet = linkedHashMap.keySet().toArray();
-
-    assertEquals("[A, BB, CCC]", Arrays.toString(keySet));
-  }
-
-}

core-java-8/src/test/java/com/baeldung/util/CurrentDateTimeUnitTest.java

@@ -1,7 +1,6 @@
 package com.baeldung.util;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
 
 import java.time.Clock;
 import java.time.Instant;
@@ -10,8 +9,6 @@ import java.time.LocalTime;
 import java.time.ZoneId;
 import java.time.temporal.ChronoField;
 
-import org.joda.time.DateTime;
-import org.joda.time.DateTimeUtils;
 import org.junit.Test;
 
 public class CurrentDateTimeUnitTest {

core-java-9/src/main/java/com/baeldung/java9/process/ChildProcess.java

@@ -0,0 +1,15 @@
+package com.baeldung.java9.process;
+
+import java.util.Scanner;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class ChildProcess {
+
+    public static void main(String[] args) {
+        @SuppressWarnings("resource")
+        Scanner input = new Scanner(System.in);
+        Logger log = Logger.getLogger(ChildProcess.class.getName());
+        log.log(Level.INFO, input.nextLine());
+    }
+}

core-java-9/src/main/java/com/baeldung/java9/process/OutputStreamExample.java

@@ -0,0 +1,16 @@
+package com.baeldung.java9.process;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class OutputStreamExample {
+
+    public static void main(String[] args) {
+        Logger log = Logger.getLogger(OutputStreamExample.class.getName());
+        log.log(Level.INFO, Integer.toString(sum(1,2)));
+    }
+
+    public static int sum(int a, int b) {
+        return a + b;
+    }
+}

core-java-9/src/main/java/com/baeldung/java9/process/ProcessCompilationError.java

@@ -0,0 +1,7 @@
+package com.baeldung.java9.process;
+
+public class ProcessCompilationError {
+    //This method has been written to generate error to display 
+    //how process errorStream() can consume error
+    public static void();
+}

core-java-9/src/main/java/com/baeldung/java9/process/ProcessUnderstanding.java

@@ -0,0 +1,110 @@
+package com.baeldung.java9.process;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.util.Optional;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class ProcessUnderstanding {
+
+    public static int compileAndRunJavaProgram() throws IOException {
+        Process process = Runtime.getRuntime()
+            .exec("javac -cp src src\\main\\java\\com\\baeldung\\java9\\process\\OutputStreamExample.java");
+        process = Runtime.getRuntime()
+            .exec("java -cp  src/main/java com.baeldung.java9.process.OutputStreamExample");
+        BufferedReader output = new BufferedReader(new InputStreamReader(process.getInputStream()));
+        int value = Integer.parseInt(output.readLine());
+        return value;
+    }
+
+    public static String getErrorStreamExample() throws IOException {
+        Process process = Runtime.getRuntime()
+            .exec("javac -cp src src\\main\\java\\com\\baeldung\\java9\\process\\ProcessCompilationError.java");
+        BufferedReader error = new BufferedReader(new InputStreamReader(process.getErrorStream()));
+        String errorString = error.readLine();
+        return errorString;
+    }
+
+    public static void creatingNewProcess() throws IOException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+    }
+
+    public static int filterProcessWithStreamsInSpecificRangeReturnCount() {
+        return (int) ProcessHandle.allProcesses()
+            .filter(ph -> (ph.pid() > 10000 && ph.pid() < 50000))
+            .count();
+    }
+
+    public static void destroyingProcessCreatedBySameProcess() throws IOException, InterruptedException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        Thread.sleep(10000);
+        process.destroy();
+    }
+
+    public static void destroyingProcessCreatedByDifferentProcess() {
+        // find out the process id of current running task by checking
+        // task manager in windows and enter the integer value
+        Optional<ProcessHandle> optionalProcessHandle = ProcessHandle.of(5232);
+        ProcessHandle processHandle = optionalProcessHandle.get();
+        processHandle.destroy();
+    }
+
+    public static int waitForExample() throws IOException, InterruptedException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        return process.waitFor();
+    }
+
+    public static int exitValueExample() throws IOException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        process.destroy();
+        return process.exitValue();
+    }
+
+    public static void destroyExample() throws IOException, InterruptedException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        Thread.sleep(10000);
+        process.destroy();
+    }
+
+    public static void destroyForciblyExample() throws IOException, InterruptedException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        Thread.sleep(10000);
+        process.destroy();
+        if (process.isAlive()) {
+            process.destroyForcibly();
+        }
+    }
+
+    public static void outputStreamDemo() throws IOException, InterruptedException {
+        Logger log = Logger.getLogger(ProcessUnderstanding.class.getName());
+        Process pr = Runtime.getRuntime()
+            .exec("javac -cp src src\\main\\java\\com\\baeldung\\java9\\process\\ChildProcess.java");
+        final Process process = Runtime.getRuntime()
+            .exec("java -cp  src/main/java com.baeldung.java9.process.ChildProcess");
+        try (Writer w = new OutputStreamWriter(process.getOutputStream(), "UTF-8")) {
+            w.write("send to child\n");
+        }
+        new Thread(() -> {
+            try {
+                int c;
+                while ((c = process.getInputStream()
+                    .read()) != -1)
+                    System.out.write((byte) c);
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+        }).start();
+        // send to child
+        log.log(Level.INFO, "rc=" + process.waitFor());
+    }
+}

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

@@ -0,0 +1,121 @@
+package com.baeldung.java9.process;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.lang.String;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+import java.lang.Integer;
+
+import org.junit.jupiter.api.Test;
+
+class ProcessUnderstandingTest {
+
+    @Test
+    public void givenSourceProgram_whenExecutedFromAnotherProgram_thenSourceProgramOutput3() throws IOException {
+        Process process = Runtime.getRuntime()
+            .exec("javac -cp src src\\main\\java\\com\\baeldung\\java9\\process\\OutputStreamExample.java");
+        process = Runtime.getRuntime()
+            .exec("java -cp  src/main/java com.baeldung.java9.process.OutputStreamExample");
+        BufferedReader output = new BufferedReader(new InputStreamReader(process.getInputStream()));
+        int value = Integer.parseInt(output.readLine());
+        assertEquals(3, value);            
+    }
+
+    @Test
+    public void givenSourceProgram_whenReadingInputStream_thenFirstLineEquals3() throws IOException {
+        Process process = Runtime.getRuntime()
+            .exec("javac -cp src src\\main\\java\\com\\baeldung\\java9\\process\\OutputStreamExample.java");
+        process = Runtime.getRuntime()
+            .exec("java -cp  src/main/java com.baeldung.java9.process.OutputStreamExample");
+        BufferedReader output = new BufferedReader(new InputStreamReader(process.getInputStream()));
+        int value = Integer.parseInt(output.readLine());
+        assertEquals(3, value);                   
+    }
+
+    @Test
+    public void givenSubProcess_whenEncounteringError_thenErrorStreamNotNull() throws IOException {
+        Process process = Runtime.getRuntime()
+            .exec("javac -cp src src\\main\\java\\com\\baeldung\\java9\\process\\ProcessCompilationError.java");
+        BufferedReader error = new BufferedReader(new InputStreamReader(process.getErrorStream()));
+        String errorString = error.readLine();
+        assertNotNull(errorString);
+    }
+
+    //@Test - windows specific
+    public void givenSubProcess_thenStartSuccessIsAlive() throws IOException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        assertTrue(builder.start().isAlive());
+    }
+
+    //@Test - windows specific
+    public void givenSubProcess_whenDestroying_thenProcessNotAlive() throws IOException, InterruptedException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        Thread.sleep(10000);
+        process.destroy();
+        assertFalse(process.isAlive());
+    }
+
+    //@Test - windows specific
+    public void givenSubProcess_whenAlive_thenDestroyForcibly() throws IOException, InterruptedException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        Thread.sleep(10000);
+        process.destroy();
+        if (process.isAlive()) {
+            process.destroyForcibly();
+        }
+        assertFalse(process.isAlive());
+    }
+
+    //@Test - windows specific
+    public void givenSubProcess_checkAlive() throws IOException, InterruptedException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        Thread.sleep(10000);
+        process.destroy();
+        assertFalse(process.isAlive());
+    }
+
+    @Test
+    public void givenProcessNotCreated_fromWithinJavaApplicationDestroying_thenProcessNotAlive() {
+        Optional<ProcessHandle> optionalProcessHandle = ProcessHandle.of(5232);
+        ProcessHandle processHandle = optionalProcessHandle.get();
+        processHandle.destroy();
+        assertFalse(processHandle.isAlive());
+    }
+
+    //@Test - windows specific
+    public void givenSubProcess_whenCurrentThreadWaitsIndefinitelyuntilSubProcessEnds_thenProcessWaitForReturnsGrt0() throws IOException, InterruptedException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        assertThat(process.waitFor() >= 0);
+    }
+
+    //@Test - windows specific
+    public void givenSubProcess_whenCurrentThreadWaitsAndSubProcessNotTerminated_thenProcessWaitForReturnsFalse() throws IOException, InterruptedException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        assertFalse(process.waitFor(1, TimeUnit.SECONDS));
+    }
+
+    //@Test - windows specific
+    public void givenSubProcess_whenCurrentThreadWillNotWaitIndefinitelyforSubProcessToEnd_thenProcessExitValueReturnsGrt0() throws IOException {
+        ProcessBuilder builder = new ProcessBuilder("notepad.exe");
+        Process process = builder.start();
+        assertThat(process.exitValue() >= 0);
+    }
+
+    @Test
+    public void givenRunningProcesses_whenFilterOnProcessIdRange_thenGetSelectedProcessPid() {
+        assertThat(((int) ProcessHandle.allProcesses()
+            .filter(ph -> (ph.pid() > 10000 && ph.pid() < 50000))
+            .count()) > 0);
+    }
+}

core-java-collections/README.md

@@ -37,3 +37,9 @@
 - [How to Convert List to Map in Java](http://www.baeldung.com/java-list-to-map)
 - [Initializing HashSet at the Time of Construction](http://www.baeldung.com/java-initialize-hashset)
 - [Removing the First Element of an Array](https://www.baeldung.com/java-array-remove-first-element)
+- [Fail-Safe Iterator vs Fail-Fast Iterator](http://www.baeldung.com/java-fail-safe-vs-fail-fast-iterator)
+- [Shuffling Collections In Java](http://www.baeldung.com/java-shuffle-collection)
+- [How to Find an Element in a List with Java](http://www.baeldung.com/find-list-element-java)
+- [An Introduction to Java.util.Hashtable Class](http://www.baeldung.com/java-hash-table)
+- [Copy a List to Another List in Java](http://www.baeldung.com/java-copy-list-to-another)
+- [Finding Max/Min of a List or Collection](http://www.baeldung.com/java-collection-min-max)

core-java-collections/src/main/java/com/baeldung/java/list/CopyListService.java

@@ -1,4 +1,4 @@
-package com.baeldung.list;
+package com.baeldung.java.list;
 
 import java.util.ArrayList;
 import java.util.Collections;

core-java-collections/src/test/java/com/baeldung/java/list/CopyListServiceUnitTest.java

@@ -1,13 +1,17 @@
-package com.baeldung.list;
+package com.baeldung.java.list;
 
-import org.junit.Before;
+import static org.junit.Assert.assertEquals;
-import org.junit.Test;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
-import static org.junit.Assert.*;
+import org.junit.Before;
+import org.junit.Test;
 
 public class CopyListServiceUnitTest {
 

core-java/src/main/java/com/baeldung/linesintersection/LinesIntersectionService.java

@@ -1,21 +0,0 @@
-package com.baeldung.linesintersection;
-
-import java.awt.Point;
-import java.util.Optional;
-
-public class LinesIntersectionService {
-
-    public Optional<Point> calculateIntersectionPoint(float m1, float b1, float m2, float b2) {
-
-        if (m1 == m2) {
-            return Optional.empty();
-        }
-        
-        float x = (b2 - b1) / (m1 - m2);
-        float y = m1 * x + b1;
-
-        Point point = new Point(Math.round(x), Math.round(y));
-
-        return Optional.of(point);
-    }
-}

core-java/src/main/java/com/baeldung/string/AppendCharAtPositionX.java

@@ -0,0 +1,45 @@
+/**
+ * 
+ */
+package com.baeldung.string;
+
+/**
+ * @author swpraman
+ *
+ */
+public class AppendCharAtPositionX {
+    
+    public String addCharUsingCharArray(String str, char ch, int position) {
+        validate(str, position);
+        int len = str.length();
+        char[] updatedArr = new char[len + 1];
+        str.getChars(0, position, updatedArr, 0);
+        updatedArr[position] = ch;
+        str.getChars(position, len, updatedArr, position + 1);
+        return new String(updatedArr);
+    }
+
+    public String addCharUsingSubstring(String str, char ch, int position) {
+        validate(str, position);
+        return str.substring(0, position) + ch + str.substring(position);
+    }
+
+    public String addCharUsingStringBuilder(String str, char ch, int position) {
+        validate(str, position);
+        StringBuilder sb = new StringBuilder(str);
+        sb.insert(position, ch);
+        return sb.toString();
+    }
+    
+    private void validate(String str, int position) {
+        if (str == null) {
+            throw new IllegalArgumentException("Str should not be null");
+        }
+        int len = str.length();
+        if (position < 0 || position > len) {
+            throw new IllegalArgumentException("position[" + position + "] should be " 
+                            + "in the range 0.." + len + " for string " + str);
+        }
+    }
+
+}

core-java/src/main/java/com/baeldung/synthetic/BridgeMethodDemo.java

@@ -0,0 +1,23 @@
+package com.baeldung.synthetic;
+
+import java.util.Comparator;
+
+/**
+ * Class which contains a synthetic bridge method.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class BridgeMethodDemo implements Comparator<Integer> {
+
+    /*
+     * (non-Javadoc)
+     * 
+     * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
+     */
+    @Override
+    public int compare(Integer o1, Integer o2) {
+        return 0;
+    }
+
+}

core-java/src/main/java/com/baeldung/synthetic/SyntheticConstructorDemo.java

@@ -0,0 +1,34 @@
+package com.baeldung.synthetic;
+
+/**
+ * Wrapper for a class which contains a synthetic constructor.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class SyntheticConstructorDemo {
+
+    /**
+     * We need to instantiate the {@link NestedClass} using a private
+     * constructor from the enclosing instance in order to generate a synthetic
+     * constructor.
+     */
+    private NestedClass nestedClass = new NestedClass();
+
+    /**
+     * Class which contains a synthetic constructor.
+     * 
+     * @author Donato Rimenti
+     *
+     */
+    class NestedClass {
+
+        /**
+         * In order to generate a synthetic constructor, this class must have a
+         * private constructor.
+         */
+        private NestedClass() {
+        }
+    }
+
+}

core-java/src/main/java/com/baeldung/synthetic/SyntheticFieldDemo.java

@@ -0,0 +1,22 @@
+package com.baeldung.synthetic;
+
+/**
+ * Wrapper for a class which contains a synthetic field reference to the outer
+ * class.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class SyntheticFieldDemo {
+
+    /**
+     * Class which contains a synthetic field reference to the outer class.
+     * 
+     * @author Donato Rimenti
+     *
+     */
+    class NestedClass {
+
+    }
+
+}

core-java/src/main/java/com/baeldung/synthetic/SyntheticMethodDemo.java

@@ -0,0 +1,48 @@
+package com.baeldung.synthetic;
+
+/**
+ * Wrapper for a class which contains two synthetic methods accessors to a
+ * private field.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class SyntheticMethodDemo {
+
+    /**
+     * Class which contains two synthetic methods accessors to a private field.
+     * 
+     * @author Donato Rimenti
+     *
+     */
+    class NestedClass {
+
+        /**
+         * Field for which will be generated synthetic methods accessors. It's
+         * important that this field is private for this purpose.
+         */
+        private String nestedField;
+    }
+
+    /**
+     * Gets the private nested field. We need to read the nested field in order
+     * to generate the synthetic getter.
+     * 
+     * @return the {@link NestedClass#nestedField}
+     */
+    public String getNestedField() {
+        return new NestedClass().nestedField;
+    }
+
+    /**
+     * Sets the private nested field. We need to write the nested field in order
+     * to generate the synthetic setter.
+     * 
+     * @param nestedField
+     *            the {@link NestedClass#nestedField}
+     */
+    public void setNestedField(String nestedField) {
+        new NestedClass().nestedField = nestedField;
+    }
+
+}

core-java/src/test/java/com/baeldung/string/AppendCharAtPositionXUnitTest.java

@@ -0,0 +1,110 @@
+/**
+ * 
+ */
+package com.baeldung.string;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+/**
+ * @author swpraman
+ *
+ */
+public class AppendCharAtPositionXUnitTest {
+    
+    private AppendCharAtPositionX appendCharAtPosition = new AppendCharAtPositionX();
+    private String word = "Titanc";
+    private char letter = 'i';
+    
+    @Test
+    public void whenUsingCharacterArrayAndCharacterAddedAtBeginning_shouldAddCharacter() {
+        assertEquals("iTitanc", appendCharAtPosition.addCharUsingCharArray(word, letter, 0));
+    }
+    
+    @Test
+    public void whenUsingSubstringAndCharacterAddedAtBeginning_shouldAddCharacter() {
+        assertEquals("iTitanc", appendCharAtPosition.addCharUsingSubstring(word, letter, 0));
+    }  
+    
+    @Test
+    public void whenUsingStringBuilderAndCharacterAddedAtBeginning_shouldAddCharacter() {
+        assertEquals("iTitanc", appendCharAtPosition.addCharUsingStringBuilder(word, letter, 0));
+    }
+    
+    @Test
+    public void whenUsingCharacterArrayAndCharacterAddedAtMiddle_shouldAddCharacter() {
+        assertEquals("Titianc", appendCharAtPosition.addCharUsingCharArray(word, letter, 3));
+    }
+    
+    @Test
+    public void whenUsingSubstringAndCharacterAddedAtMiddle_shouldAddCharacter() {
+        assertEquals("Titianc", appendCharAtPosition.addCharUsingSubstring(word, letter, 3));
+    }  
+    
+    @Test
+    public void whenUsingStringBuilderAndCharacterAddedAtMiddle_shouldAddCharacter() {
+        assertEquals("Titianc", appendCharAtPosition.addCharUsingStringBuilder(word, letter, 3));
+    }
+    
+    @Test
+    public void whenUsingCharacterArrayAndCharacterAddedAtEnd_shouldAddCharacter() {
+        assertEquals("Titanci", appendCharAtPosition.addCharUsingCharArray(word, letter, word.length()));
+    }
+    
+    @Test
+    public void whenUsingSubstringAndCharacterAddedAtEnd_shouldAddCharacter() {
+        assertEquals("Titanci", appendCharAtPosition.addCharUsingSubstring(word, letter, word.length()));
+    }  
+    
+    @Test
+    public void whenUsingStringBuilderAndCharacterAddedAtEnd_shouldAddCharacter() {
+        assertEquals("Titanci", appendCharAtPosition.addCharUsingStringBuilder(word, letter, word.length()));
+    }
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingCharacterArrayAndCharacterAddedAtNegativePosition_shouldThrowException() {
+        appendCharAtPosition.addCharUsingStringBuilder(word, letter, -1);
+    }
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingSubstringAndCharacterAddedAtNegativePosition_shouldThrowException() {
+        appendCharAtPosition.addCharUsingStringBuilder(word, letter, -1);
+    }  
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingStringBuilderAndCharacterAddedAtNegativePosition_shouldThrowException() {
+        appendCharAtPosition.addCharUsingStringBuilder(word, letter, -1);
+    }
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingCharacterArrayAndCharacterAddedAtInvalidPosition_shouldThrowException() {
+        appendCharAtPosition.addCharUsingStringBuilder(word, letter, word.length() + 2);
+    }
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingSubstringAndCharacterAddedAtInvalidPosition_shouldThrowException() {
+        appendCharAtPosition.addCharUsingStringBuilder(word, letter, word.length() + 2);
+    }  
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingStringBuilderAndCharacterAddedAtInvalidPosition_shouldThrowException() {
+        appendCharAtPosition.addCharUsingStringBuilder(word, letter, word.length() + 2);
+    }
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingCharacterArrayAndCharacterAddedAtPositionXAndStringIsNull_shouldThrowException() {
+        appendCharAtPosition.addCharUsingStringBuilder(null, letter, 3);
+    }
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingSubstringAndCharacterAddedAtPositionXAndStringIsNull_shouldThrowException() {
+        appendCharAtPosition.addCharUsingStringBuilder(null, letter, 3);
+    }  
+    
+    @Test(expected=IllegalArgumentException.class)
+    public void whenUsingStringBuilderAndCharacterAddedAtPositionXAndStringIsNull_shouldThrowException() {
+        appendCharAtPosition.addCharUsingStringBuilder(null, letter, 3);
+    }
+ 
+}

core-java/src/test/java/com/baeldung/synthetic/SyntheticUnitTest.java

@@ -0,0 +1,99 @@
+package com.baeldung.synthetic;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Unit test for {@link SyntheticFieldDemo}, {@link SyntheticMethodDemo},
+ * {@link SyntheticConstructorDemo} and {@link BridgeMethodDemo} classes.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class SyntheticUnitTest {
+
+    /**
+     * Tests that the {@link SyntheticMethodDemo.NestedClass} contains two synthetic
+     * methods.
+     */
+    @Test
+    public void givenSyntheticMethod_whenIsSinthetic_thenTrue() {
+        // Checks that the nested class contains exactly two synthetic methods.
+        Method[] methods = SyntheticMethodDemo.NestedClass.class.getDeclaredMethods();
+        Assert.assertEquals("This class should contain only two methods", 2, methods.length);
+
+        for (Method m : methods) {
+            System.out.println("Method: " + m.getName() + ", isSynthetic: " + m.isSynthetic());
+            Assert.assertTrue("All the methods of this class should be synthetic", m.isSynthetic());
+        }
+    }
+
+    /**
+     * Tests that {@link SyntheticConstructorDemo.NestedClass} contains a synthetic
+     * constructor.
+     */
+    @Test
+    public void givenSyntheticConstructor_whenIsSinthetic_thenTrue() {
+        // Checks that the nested class contains exactly a synthetic
+        // constructor.
+        int syntheticConstructors = 0;
+        Constructor<?>[] constructors = SyntheticConstructorDemo.NestedClass.class.getDeclaredConstructors();
+        Assert.assertEquals("This class should contain only two constructors", 2, constructors.length);
+
+        for (Constructor<?> c : constructors) {
+            System.out.println("Constructor: " + c.getName() + ", isSynthetic: " + c.isSynthetic());
+
+            // Counts the synthetic constructors.
+            if (c.isSynthetic()) {
+                syntheticConstructors++;
+            }
+        }
+
+        // Checks that there's exactly one synthetic constructor.
+        Assert.assertEquals(1, syntheticConstructors);
+    }
+
+    /**
+     * Tests that {@link SyntheticFieldDemo.NestedClass} contains a synthetic field.
+     */
+    @Test
+    public void givenSyntheticField_whenIsSinthetic_thenTrue() {
+        // This class should contain exactly one synthetic field.
+        Field[] fields = SyntheticFieldDemo.NestedClass.class.getDeclaredFields();
+        Assert.assertEquals("This class should contain only one field", 1, fields.length);
+
+        for (Field f : fields) {
+            System.out.println("Field: " + f.getName() + ", isSynthetic: " + f.isSynthetic());
+            Assert.assertTrue("All the fields of this class should be synthetic", f.isSynthetic());
+        }
+    }
+
+    /**
+     * Tests that {@link BridgeMethodDemo} contains a synthetic bridge method.
+     */
+    @Test
+    public void givenBridgeMethod_whenIsBridge_thenTrue() {
+        // This class should contain exactly one synthetic bridge method.
+        int syntheticMethods = 0;
+        Method[] methods = BridgeMethodDemo.class.getDeclaredMethods();
+        for (Method m : methods) {
+            System.out.println(
+                    "Method: " + m.getName() + ", isSynthetic: " + m.isSynthetic() + ", isBridge: " + m.isBridge());
+
+            // Counts the synthetic methods and checks that they are also bridge
+            // methods.
+            if (m.isSynthetic()) {
+                syntheticMethods++;
+                Assert.assertTrue("The synthetic method in this class should also be a bridge method", m.isBridge());
+            }
+        }
+        
+        // Checks that there's exactly one synthetic bridge method.
+        Assert.assertEquals("There should be exactly 1 synthetic bridge method in this class", 1, syntheticMethods);
+    }
+
+}

java-streams/pom.xml

@@ -1,7 +1,6 @@
 <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>java-streams</artifactId>
     <version>0.1.0-SNAPSHOT</version>
     <packaging>jar</packaging>
@@ -15,17 +14,17 @@
     </parent>
 
     <dependencies>
-        <!-- https://mvnrepository.com/artifact/org.openjdk.jmh/jmh-core -->	
+        <!-- https://mvnrepository.com/artifact/org.openjdk.jmh/jmh-core -->
-        <dependency>	
+        <dependency>
-            <groupId>org.openjdk.jmh</groupId>	
+            <groupId>org.openjdk.jmh</groupId>
-            <artifactId>jmh-core</artifactId>	
+            <artifactId>jmh-core</artifactId>
-            <version>${jmh.version}</version>	
+            <version>${jmh.version}</version>
-        </dependency>	
+        </dependency>
-         <dependency>	
+        <dependency>
-            <groupId>org.openjdk.jmh</groupId>	
+            <groupId>org.openjdk.jmh</groupId>
-            <artifactId>jmh-generator-annprocess</artifactId>	
+            <artifactId>jmh-generator-annprocess</artifactId>
-            <version>${jmh.version}</version>	
+            <version>${jmh.version}</version>
-            <scope>provided</scope>	
+            <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>

java-streams/src/test/java/com/baeldung/stream/PrimitiveStreamsUnitTest.java

@@ -1,15 +1,14 @@
 package com.baeldung.stream;
 
-import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
-import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 
-import static org.junit.Assert.assertEquals;
+import org.junit.Test;
-import static org.junit.Assert.assertTrue;
 
 public class PrimitiveStreamsUnitTest {
 
@@ -17,7 +16,7 @@ public class PrimitiveStreamsUnitTest {
 
     @Test
     public void givenAnArrayOfIntegersWhenMinIsCalledThenCorrectMinIsReturned() {
-        int[] integers = new int[] {20, 98, 12, 7, 35};
+        int[] integers = new int[] { 20, 98, 12, 7, 35 };
         int min = streams.min(integers); // returns 7
 
         assertEquals(7, min);
@@ -66,19 +65,14 @@ public class PrimitiveStreamsUnitTest {
     @Test
     public void givenAnArrayWhenSumIsCalledThenTheCorrectSumIsReturned() {
 
-        int sum = Stream.of(33,45)
+        int sum = Stream.of(33, 45).mapToInt(i -> i).sum();
-          .mapToInt(i -> i)
-          .sum();
 
         assertEquals(78, sum);
     }
 
     @Test
     public void givenAnIntStreamThenGetTheEvenIntegers() {
-        List<Integer> evenInts = IntStream.rangeClosed(1, 10)
+        List<Integer> evenInts = IntStream.rangeClosed(1, 10).filter(i -> i % 2 == 0).boxed().collect(Collectors.toList());
-          .filter(i -> i % 2 == 0)
-          .boxed()
-          .collect(Collectors.toList());
 
         List<Integer> expected = IntStream.of(2, 4, 6, 8, 10).boxed().collect(Collectors.toList());
 

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

@@ -18,7 +18,6 @@ import java.util.stream.IntStream;
 public class BenchmarkUnitTest
 {
 
-  @Test
   public void
   launchBenchmark() throws Exception {
 

java-strings/src/main/java/com/baeldung/string/sorting/AnagramValidator.java

@@ -0,0 +1,29 @@
+package com.baeldung.string.sorting;
+
+import java.util.Arrays;
+
+public class AnagramValidator {
+
+    public static boolean isValid(String text, String anagram) {
+        text = prepare(text);
+        anagram = prepare(anagram);
+
+        String sortedText = sort(text);
+        String sortedAnagram = sort(anagram);
+
+        return sortedText.equals(sortedAnagram);
+    }
+
+    private static String sort(String text) {
+        char[] chars = prepare(text).toCharArray();
+
+        Arrays.sort(chars);
+        return new String(chars);
+    }
+
+    private static String prepare(String text) {
+        return text.toLowerCase()
+            .trim()
+            .replaceAll("\\s+", "");
+    }
+}

java-strings/src/test/java/com/baeldung/string/formatter/DateToStringFormatterUnitTest.java

@@ -0,0 +1,67 @@
+package com.baeldung.string.formatter;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.TimeZone;
+
+import static org.junit.Assert.assertEquals;
+
+public class DateToStringFormatterUnitTest {
+
+    private static final String DATE_FORMAT = "MMM d, yyyy HH:mm a";
+    private static final String EXPECTED_STRING_DATE = "Aug 1, 2018 12:00 PM";
+    private static Date date;
+
+    @BeforeClass
+    public static void setUp() {
+        TimeZone.setDefault(TimeZone.getTimeZone("CET"));
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(2018, Calendar.AUGUST, 1, 12, 0);
+        date = calendar.getTime();
+    }
+
+    @Test
+    public void whenDateConvertedUsingSimpleDateFormatToString_thenCorrect() {
+        DateFormat formatter = new SimpleDateFormat(DATE_FORMAT);
+        String formattedDate = formatter.format(date);
+
+        assertEquals(EXPECTED_STRING_DATE, formattedDate);
+    }
+
+    @Test
+    public void whenDateConvertedUsingDateFormatToString_thenCorrect() {
+        String formattedDate = DateFormat
+          .getDateTimeInstance(DateFormat.MEDIUM, DateFormat.SHORT)
+          .format(date);
+
+        assertEquals(EXPECTED_STRING_DATE, formattedDate);
+    }
+
+    @Test
+    public void whenDateConvertedUsingFormatterToString_thenCorrect() {
+        String formattedDate = String.format("%1$tb %1$te, %1$tY %1$tI:%1$tM %1$Tp", date);
+
+        assertEquals(EXPECTED_STRING_DATE, formattedDate);
+    }
+
+    @Test
+    public void whenDateConvertedUsingDateTimeApiToString_thenCorrect() {
+        DateTimeFormatter fmt = DateTimeFormatter.ofPattern(DATE_FORMAT);
+        Instant instant = date.toInstant();
+        LocalDateTime ldt = instant
+          .atZone(ZoneId.of("CET"))
+          .toLocalDateTime();
+        String formattedDate = ldt.format(fmt);
+
+        assertEquals(EXPECTED_STRING_DATE, formattedDate);
+    }
+}

java-strings/src/test/java/com/baeldung/string/sorting/AnagramValidatorUnitTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.string.sorting;
+
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.string.sorting.AnagramValidator;
+
+class AnagramValidatorUnitTest {
+    
+    @Test
+    void givenValidAnagrams_whenSorted_thenEqual() {
+        boolean isValidAnagram = AnagramValidator.isValid("Avida Dollars", "Salvador Dali");
+        
+        assertTrue(isValidAnagram);
+    }
+    
+    @Test
+    void givenNotValidAnagrams_whenSorted_thenNotEqual() {
+        boolean isValidAnagram = AnagramValidator.isValid("abc", "def");
+        
+        assertFalse(isValidAnagram);
+    }
+}

java-strings/src/test/java/com/baeldung/string/sorting/SortStringUnitTest.java

@@ -0,0 +1,31 @@
+package com.baeldung.string.sorting;
+
+import java.util.Arrays;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class SortStringUnitTest {
+
+    @Test
+    void givenString_whenSort_thenSorted() {
+        String abcd = "bdca";
+        char[] chars = abcd.toCharArray();
+
+        Arrays.sort(chars);
+        String sorted = new String(chars);
+
+        assertThat(sorted).isEqualTo("abcd");
+    }
+
+    @Test
+    void givenString_whenSortJava8_thenSorted() {
+        String sorted = "bdca".chars()
+            .sorted()
+            .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
+            .toString();
+
+        assertThat(sorted).isEqualTo("abcd");
+    }
+}

jersey-client-rx/pom.xml

@@ -1,67 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <groupId>com.baeldung.samples</groupId>
-    <artifactId>jersey-client-rx</artifactId>
-    <version>1.0</version>
-    <packaging>jar</packaging>
-    <dependencies>
-        <dependency>
-            <groupId>org.glassfish.jersey.inject</groupId>
-            <artifactId>jersey-hk2</artifactId>
-            <version>2.27</version>
-        </dependency>
-        <dependency>
-            <groupId>org.glassfish.jersey.core</groupId>
-            <artifactId>jersey-client</artifactId>
-            <version>2.27</version>
-        </dependency>
-        <dependency>
-            <groupId>org.glassfish.jersey.ext.rx</groupId>
-            <artifactId>jersey-rx-client-rxjava</artifactId>
-            <version>2.27</version>
-        </dependency>
-        <dependency>
-            <groupId>org.glassfish.jersey.ext.rx</groupId>
-            <artifactId>jersey-rx-client-rxjava2</artifactId>
-            <version>2.27</version>
-        </dependency>
-        <dependency>
-            <groupId>com.github.tomakehurst</groupId>
-            <artifactId>wiremock</artifactId>
-            <version>1.58</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.vintage</groupId>
-            <artifactId>junit-vintage-engine</artifactId>
-            <version>5.2.0</version>
-        </dependency>
-        <dependency>
-            <groupId>org.glassfish.jersey.media</groupId>
-            <artifactId>jersey-media-json-jackson</artifactId>
-            <version>2.25</version>
-        </dependency>
-        <dependency>
-            <groupId>com.fasterxml.jackson.jaxrs</groupId>
-            <artifactId>jackson-jaxrs-json-provider</artifactId>
-            <version>2.4.1</version>
-        </dependency>
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-jdk14</artifactId>
-            <version>1.7.25</version>
-        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>3.10.0</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-    <properties>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <maven.compiler.source>1.8</maven.compiler.source>
-        <maven.compiler.target>1.8</maven.compiler.target>
-    </properties>
-</project>

jersey-client-rx/readme.md

@@ -1,3 +0,0 @@
-# Fluent, Reactive Jersey Client Orchestration #
-
-### Sample code demonstrating the options for asynchronous, reactive RESTful service consumption with JAX-RS ###

jersey/src/main/java/com/baeldung/jersey/server/Responder.java

@@ -0,0 +1,102 @@
+package com.baeldung.jersey.server;
+
+import com.baeldung.jersey.server.model.Person;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+
+@Path("/response")
+public class Responder {
+
+    @GET
+    @Path("/ok")
+    public Response getOkResponse() {
+
+        String message = "This is a text response";
+
+        return Response
+          .status(Response.Status.OK)
+          .entity(message)
+          .build();
+    }
+
+    @GET
+    @Path("/not_ok")
+    public Response getNOkTextResponse() {
+
+        String message = "There was an internal server error";
+
+        return Response
+          .status(Response.Status.INTERNAL_SERVER_ERROR)
+          .entity(message)
+          .build();
+    }
+
+    @GET
+    @Path("/text_plain")
+    public Response getTextResponseTypeDefined() {
+
+        String message = "This is a plain text response";
+
+        return Response
+          .status(Response.Status.OK)
+          .entity(message)
+          .type(MediaType.TEXT_PLAIN)
+          .build();
+    }
+
+    @GET
+    @Path("/text_plain_annotation")
+    @Produces({ MediaType.TEXT_PLAIN })
+    public Response getTextResponseTypeAnnotated() {
+
+        String message = "This is a plain text response via annotation";
+
+        return Response
+          .status(Response.Status.OK)
+          .entity(message)
+          .build();
+    }
+
+    @GET
+    @Path("/pojo")
+    public Response getPojoResponse() {
+
+        Person person = new Person("Abh", "Nepal");
+
+        return Response
+          .status(Response.Status.OK)
+          .entity(person)
+          .build();
+    }
+
+    @GET
+    @Path("/json")
+    public Response getJsonResponse() {
+
+        String message = "{\"hello\": \"This is a JSON response\"}";
+
+        return Response
+          .status(Response.Status.OK)
+          .entity(message)
+          .type(MediaType.APPLICATION_JSON)
+          .build();
+    }
+
+    @GET
+    @Path("/xml")
+    @Produces(MediaType.TEXT_XML)
+    public String sayXMLHello() {
+        return "<?xml version=\"1.0\"?>" + "<hello> This is a xml response </hello>";
+    }
+
+    @GET
+    @Path("/html")
+    @Produces(MediaType.TEXT_HTML)
+    public String sayHtmlHello() {
+        return "<html> " + "<title>" + " This is a html title  </title>" + "<body><h1>" + " This is a html response body " + "</body></h1>" + "</html> ";
+    }
+}

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

@@ -0,0 +1,32 @@
+package com.baeldung.jersey.server.model;
+
+public class Person {
+    String name;
+    String address;
+
+    public Person(String name, String address) {
+        this.name = name;
+        this.address = address;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+
+    @Override
+    public String toString() {
+        return "Person [name: " + getName() + " address: " + getAddress() + "]";
+    }
+}

jpa-storedprocedure/README.md

@@ -1,2 +0,0 @@
-### Relevant Articles:
-- [A Guide to Stored Procedures with JPA](http://www.baeldung.com/jpa-stored-procedures)

jpa-storedprocedure/pom.xml

@@ -1,65 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <groupId>com.baeldung</groupId>
-    <artifactId>jpa-storedprocedure</artifactId>
-    <version>1.0</version>
-    <packaging>jar</packaging>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <dependencies>
-        <!-- core library -->
-        <dependency>
-            <groupId>javax</groupId>
-            <artifactId>javaee-api</artifactId>
-            <version>${jee.version}</version>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.hibernate</groupId>
-            <artifactId>hibernate-entitymanager</artifactId>
-            <version>${hibernate.version}</version>
-        </dependency>
-        <!-- MySql JDBC -->
-        <dependency>
-            <groupId>mysql</groupId>
-            <artifactId>mysql-connector-java</artifactId>
-            <version>${mysql.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>commons-io</groupId>
-            <artifactId>commons-io</artifactId>
-            <version>${commons-io.version}</version>
-        </dependency>
-    </dependencies>
-
-    <build>
-        <finalName>JpaStoredProcedure</finalName>
-        <plugins>
-            <plugin>
-                <artifactId>maven-assembly-plugin</artifactId>
-                <configuration>
-                    <archiveBaseDirectory>${project.basedir}</archiveBaseDirectory>
-                    <!--archive> <manifest> <mainClass>fully.qualified.MainClass</mainClass> </manifest> </archive -->
-                    <descriptorRefs>
-                        <descriptorRef>jar-with-dependencies</descriptorRef>
-                    </descriptorRefs>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
-
-    <properties>
-        <jee.version>7.0</jee.version>
-        <hibernate.version>5.2.5.Final</hibernate.version>
-        <mysql.version>6.0.5</mysql.version>
-        <commons-io.version>2.5</commons-io.version>
-    </properties>
-
-</project>

jpa-storedprocedure/src/main/resources/META-INF/persistence.xml

@@ -1,20 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
-			 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-			 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
-             http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
-			 version="2.1">
-
-	<persistence-unit name="jpa-db">
-		<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
-		<class>com.baeldung.jpa.model.Car</class>
-		<properties>
-			<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
-			<property name="javax.persistence.jdbc.url" value="jdbc:mysql://127.0.0.1:3306/baeldung" />
-			<property name="javax.persistence.jdbc.user" value="baeldung" />
-			<property name="javax.persistence.jdbc.password" value="YourPassword" />
-			<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
-			<property name="hibernate.show_sql" value="true" />
-		</properties>
-	</persistence-unit>
-</persistence>

jpa-storedprocedure/src/main/resources/logback.xml

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

libraries-server/README.md

@@ -0,0 +1,9 @@
+### Relevant articles
+
+- [Embedded Jetty Server in Java](http://www.baeldung.com/jetty-embedded)
+- [Introduction to Netty](http://www.baeldung.com/netty)
+- [Exceptions in Netty](http://www.baeldung.com/netty-exception-handling)
+- [Programatically Create, Configure, and Run a Tomcat Server](http://www.baeldung.com/tomcat-programmatic-setup)
+- [Creating and Configuring Jetty 9 Server in Java](http://www.baeldung.com/jetty-java-programmatic)
+- [Testing Netty with EmbeddedChannel](http://www.baeldung.com/testing-netty-embedded-channel)
+

libraries-server/pom.xml

@@ -14,6 +14,73 @@
             <groupId>org.eclipse.paho</groupId>
             <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
             <version>1.2.0</version>
-        </dependency>	
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/org.assertj/assertj-core -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.eclipse.jetty</groupId>
+            <artifactId>jetty-server</artifactId>
+            <version>${jetty.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.eclipse.jetty</groupId>
+            <artifactId>jetty-servlet</artifactId>
+            <version>${jetty.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.eclipse.jetty</groupId>
+            <artifactId>jetty-webapp</artifactId>
+            <version>${jetty.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>${httpclient.version}</version>
+            <exclusions>
+                <exclusion>
+                    <artifactId>commons-logging</artifactId>
+                    <groupId>commons-logging</groupId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons.io.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.netty</groupId>
+            <artifactId>netty-all</artifactId>
+            <version>${netty.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+		
+        <!-- tomcat -->
+        <dependency>
+            <groupId>org.apache.tomcat</groupId>
+            <artifactId>tomcat-catalina</artifactId>
+            <version>${tomcat.version}</version>
+        </dependency>
     </dependencies>
- </project>
+
+    <properties>
+        <assertj.version>3.6.2</assertj.version>
+        <httpclient.version>4.5.3</httpclient.version>
+        <commons.io.version>2.5</commons.io.version>
+        <jetty.version>9.4.8.v20171121</jetty.version>
+        <netty.version>4.1.20.Final</netty.version>
+        <commons.collections.version>4.1</commons.collections.version>
+        <junit.version>4.12</junit.version>
+        <tomcat.version>8.5.24</tomcat.version>
+    </properties>
+
+</project>

libraries/README.md

@@ -5,13 +5,11 @@
 - [String Processing with Apache Commons Lang 3](http://www.baeldung.com/string-processing-commons-lang)
 - [Introduction to Javatuples](http://www.baeldung.com/java-tuples)
 - [Introduction to Javassist](http://www.baeldung.com/javassist)
-- [Embedded Jetty Server in Java](http://www.baeldung.com/jetty-embedded)
 - [Introduction to Apache Flink with Java](http://www.baeldung.com/apache-flink)
 - [Introduction to JSONassert](http://www.baeldung.com/jsonassert)
 - [Intro to JaVers](http://www.baeldung.com/javers)
 - [Introduction to Apache Commons Math](http://www.baeldung.com/apache-commons-math)
 - [Intro to Serenity BDD](http://www.baeldung.com/serenity-bdd)
-- [Introduction to Netty](http://www.baeldung.com/netty)
 - [Merging Streams in Java](http://www.baeldung.com/java-merge-streams)
 - [Serenity BDD and Screenplay](http://www.baeldung.com/serenity-screenplay)
 - [Introduction to Quartz](http://www.baeldung.com/quartz)
@@ -54,10 +52,7 @@
 - [Introduction to BouncyCastle with Java](http://www.baeldung.com/java-bouncy-castle)
 - [Guide to google-http-client](http://www.baeldung.com/google-http-client)
 - [Interact with Google Sheets from Java](http://www.baeldung.com/google-sheets-java-client)
-- [Programatically Create, Configure, and Run a Tomcat Server](http://www.baeldung.com/tomcat-programmatic-setup)
 - [A Docker Guide for Java](http://www.baeldung.com/docker-java-api)
-- [Exceptions in Netty](http://www.baeldung.com/netty-exception-handling)
-- [Creating and Configuring Jetty 9 Server in Java](http://www.baeldung.com/jetty-java-programmatic)
 - [Introduction To OpenCSV](http://www.baeldung.com/opencsv)
 - [Introduction to Akka Actors in Java](http://www.baeldung.com/akka-actors-java)
 - [Asynchronous HTTP with async-http-client in Java](http://www.baeldung.com/async-http-client)
@@ -77,7 +72,6 @@
 - [Publish and Receive Messages with Nats Java Client](http://www.baeldung.com/nats-java-client)
 - [Java Concurrency Utility with JCTools](http://www.baeldung.com/java-concurrency-jc-tools)
 - [Apache Commons Collections MapUtils](http://www.baeldung.com/apache-commons-map-utils)
-- [Testing Netty with EmbeddedChannel](http://www.baeldung.com/testing-netty-embedded-channel)
 - [Creating REST Microservices with Javalin](http://www.baeldung.com/javalin-rest-microservices)
 - [Introduction to JavaPoet](http://www.baeldung.com/java-poet)
 - [Introduction to Joda-Time](http://www.baeldung.com/joda-time)

libraries/pom.xml

@@ -106,21 +106,6 @@
             <artifactId>javers-core</artifactId>
             <version>${javers.version}</version>
         </dependency>
-        <dependency>
-            <groupId>org.eclipse.jetty</groupId>
-            <artifactId>jetty-server</artifactId>
-            <version>${jetty.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.eclipse.jetty</groupId>
-            <artifactId>jetty-servlet</artifactId>
-            <version>${jetty.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.eclipse.jetty</groupId>
-            <artifactId>jetty-webapp</artifactId>
-            <version>${jetty.version}</version>
-        </dependency>
 
         <dependency>
             <groupId>io.nats</groupId>
@@ -169,6 +154,17 @@
             <artifactId>commons-dbutils</artifactId>
             <version>${commons.dbutils.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.apache.flink</groupId>
+            <artifactId>flink-connector-kafka-0.11_2.11</artifactId>
+            <version>${flink.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.flink</groupId>
+            <artifactId>flink-streaming-java_2.11</artifactId>
+            <version>${flink.version}</version>
+        </dependency>
+
         <dependency>
             <groupId>org.apache.flink</groupId>
             <artifactId>flink-core</artifactId>
@@ -193,7 +189,7 @@
         </dependency>
         <dependency>
             <groupId>org.apache.flink</groupId>
-            <artifactId>flink-test-utils_2.10</artifactId>
+            <artifactId>flink-test-utils_2.11</artifactId>
             <version>${flink.version}</version>
             <scope>test</scope>
         </dependency>
@@ -243,6 +239,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.datatype</groupId>
+            <artifactId>jackson-datatype-jsr310</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
         <!-- JDO -->
         <dependency>
             <groupId>org.datanucleus</groupId>
@@ -379,11 +380,6 @@
             <artifactId>jmh-generator-annprocess</artifactId>
             <version>${jmh.version}</version>
         </dependency>
-        <dependency>
-            <groupId>io.netty</groupId>
-            <artifactId>netty-all</artifactId>
-            <version>${netty.version}</version>
-        </dependency>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
@@ -658,13 +654,7 @@
             <classifier>test</classifier>
             <scope>test</scope>
         </dependency>
-
+		
-        <!-- tomcat -->
-        <dependency>
-            <groupId>org.apache.tomcat</groupId>
-            <artifactId>tomcat-catalina</artifactId>
-            <version>${tomcat.version}</version>
-        </dependency>
         <dependency>
             <groupId>org.milyn</groupId>
             <artifactId>milyn-smooks-all</artifactId>
@@ -924,12 +914,11 @@
         <commons.io.version>2.5</commons.io.version>
         <commons.dbutils.version>1.6</commons.dbutils.version>
         <h2.version>1.4.196</h2.version>
-        <jetty.version>9.4.8.v20171121</jetty.version>
         <jnats.version>1.0</jnats.version>
 
         <httpclient.version>4.5.3</httpclient.version>
         <commons.io.version>2.5</commons.io.version>
-        <flink.version>1.2.0</flink.version>
+        <flink.version>1.5.0</flink.version>
         <jackson.version>2.8.5</jackson.version>
         <neuroph.version>2.92</neuroph.version>
         <serenity.version>1.9.26</serenity.version>
@@ -937,7 +926,6 @@
         <serenity.jira.version>1.9.0</serenity.jira.version>
         <serenity.plugin.version>1.9.27</serenity.plugin.version>
         <jUnitParams.version>1.1.0</jUnitParams.version>
-        <netty.version>4.1.20.Final</netty.version>
         <commons.collections.version>4.1</commons.collections.version>
         <junit.version>4.12</junit.version>
         <java-lsh.version>0.10</java-lsh.version>
@@ -966,7 +954,6 @@
         <kafka.version>1.0.0</kafka.version>
         <smooks.version>1.7.0</smooks.version>
         <docker.version>3.0.14</docker.version>
-        <tomcat.version>8.5.24</tomcat.version>
         <async.http.client.version>2.2.0</async.http.client.version>
         <infinispan.version>9.1.5.Final</infinispan.version>
         <opencsv.version>4.1</opencsv.version>

libraries/src/main/java/com/baeldung/flink/FlinkDataPipeline.java

@@ -0,0 +1,82 @@
+package com.baeldung.flink;
+
+
+import com.baeldung.flink.model.Backup;
+import com.baeldung.flink.model.InputMessage;
+import com.baeldung.flink.operator.BackupAggregator;
+import com.baeldung.flink.operator.InputMessageTimestampAssigner;
+import com.baeldung.flink.operator.WordsCapitalizer;
+import org.apache.flink.streaming.api.TimeCharacteristic;
+import org.apache.flink.streaming.api.datastream.DataStream;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.windowing.time.Time;
+import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer011;
+import org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer011;
+
+import static com.baeldung.flink.connector.Consumers.*;
+import static com.baeldung.flink.connector.Producers.*;
+
+public class FlinkDataPipeline {
+
+    public static void capitalize() throws Exception {
+        String inputTopic = "flink_input";
+        String outputTopic = "flink_output";
+        String consumerGroup = "baeldung";
+        String address = "localhost:9092";
+
+        StreamExecutionEnvironment environment =
+          StreamExecutionEnvironment.getExecutionEnvironment();
+
+        FlinkKafkaConsumer011<String> flinkKafkaConsumer =
+          createStringConsumerForTopic(inputTopic, address, consumerGroup);
+        flinkKafkaConsumer.setStartFromEarliest();
+
+        DataStream<String> stringInputStream =
+          environment.addSource(flinkKafkaConsumer);
+
+        FlinkKafkaProducer011<String> flinkKafkaProducer =
+        createStringProducer(outputTopic, address);
+
+        stringInputStream
+          .map(new WordsCapitalizer())
+          .addSink(flinkKafkaProducer);
+
+        environment.execute();
+    }
+
+public static void createBackup () throws Exception {
+    String inputTopic = "flink_input";
+    String outputTopic = "flink_output";
+    String consumerGroup = "baeldung";
+    String kafkaAddress = "localhost:9092";
+
+    StreamExecutionEnvironment environment =
+      StreamExecutionEnvironment.getExecutionEnvironment();
+
+    environment.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
+
+    FlinkKafkaConsumer011<InputMessage> flinkKafkaConsumer =
+      createInputMessageConsumer(inputTopic, kafkaAddress, consumerGroup);
+    flinkKafkaConsumer.setStartFromEarliest();
+
+    flinkKafkaConsumer
+      .assignTimestampsAndWatermarks(new InputMessageTimestampAssigner());
+    FlinkKafkaProducer011<Backup> flinkKafkaProducer =
+      createBackupProducer(outputTopic, kafkaAddress);
+
+    DataStream<InputMessage> inputMessagesStream =
+      environment.addSource(flinkKafkaConsumer);
+
+    inputMessagesStream
+      .timeWindowAll(Time.hours(24))
+      .aggregate(new BackupAggregator())
+      .addSink(flinkKafkaProducer);
+
+    environment.execute();
+}
+
+    public static void main(String[] args) throws Exception {
+        createBackup();
+    }
+
+}

libraries/src/main/java/com/baeldung/flink/connector/Consumers.java

@@ -0,0 +1,32 @@
+package com.baeldung.flink.connector;
+
+import com.baeldung.flink.model.InputMessage;
+import com.baeldung.flink.schema.InputMessageDeserializationSchema;
+import org.apache.flink.api.common.serialization.SimpleStringSchema;
+import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer011;
+
+import java.util.Properties;
+
+public class Consumers {
+
+public static FlinkKafkaConsumer011<String> createStringConsumerForTopic(
+  String topic, String kafkaAddress, String kafkaGroup ) {
+    Properties props = new Properties();
+    props.setProperty("bootstrap.servers", kafkaAddress);
+    props.setProperty("group.id",kafkaGroup);
+    FlinkKafkaConsumer011<String> consumer =
+      new FlinkKafkaConsumer011<>(topic, new SimpleStringSchema(),props);
+
+    return consumer;
+}
+
+    public static FlinkKafkaConsumer011<InputMessage> createInputMessageConsumer(String topic, String kafkaAddress, String kafkaGroup ) {
+        Properties properties = new Properties();
+        properties.setProperty("bootstrap.servers", kafkaAddress);
+        properties.setProperty("group.id",kafkaGroup);
+        FlinkKafkaConsumer011<InputMessage> consumer = new FlinkKafkaConsumer011<InputMessage>(
+                topic, new InputMessageDeserializationSchema(),properties);
+
+        return consumer;
+    }
+}

libraries/src/main/java/com/baeldung/flink/connector/Producers.java

@@ -0,0 +1,17 @@
+package com.baeldung.flink.connector;
+
+import com.baeldung.flink.model.Backup;
+import com.baeldung.flink.schema.BackupSerializationSchema;
+import org.apache.flink.api.common.serialization.SimpleStringSchema;
+import org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer011;
+
+public class Producers {
+
+    public static FlinkKafkaProducer011<String> createStringProducer(String topic, String kafkaAddress) {
+        return new FlinkKafkaProducer011<>(kafkaAddress, topic, new SimpleStringSchema());
+    }
+
+    public static FlinkKafkaProducer011<Backup> createBackupProducer(String topic, String kafkaAddress) {
+        return new FlinkKafkaProducer011<Backup>(kafkaAddress, topic, new BackupSerializationSchema());
+    }
+}

libraries/src/main/java/com/baeldung/flink/model/Backup.java

@@ -0,0 +1,27 @@
+package com.baeldung.flink.model;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.UUID;
+
+public class Backup {
+
+    @JsonProperty("inputMessages")
+    List<InputMessage> inputMessages;
+    @JsonProperty("backupTimestamp")
+    LocalDateTime backupTimestamp;
+    @JsonProperty("uuid")
+    UUID uuid;
+
+    public Backup(List<InputMessage> inputMessages, LocalDateTime backupTimestamp) {
+        this.inputMessages = inputMessages;
+        this.backupTimestamp = backupTimestamp;
+        this.uuid = UUID.randomUUID();
+    }
+
+    public List<InputMessage> getInputMessages() {
+        return inputMessages;
+    }
+}

libraries/src/main/java/com/baeldung/flink/model/InputMessage.java

@@ -0,0 +1,72 @@
+package com.baeldung.flink.model;
+
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+import com.google.common.base.Objects;
+
+import java.time.LocalDateTime;
+
+@JsonSerialize
+public class InputMessage {
+    String sender;
+    String recipient;
+    LocalDateTime sentAt;
+    String message;
+
+    public InputMessage() {
+    }
+
+    public String getSender() {
+        return sender;
+    }
+
+    public void setSender(String sender) {
+        this.sender = sender;
+    }
+
+    public String getRecipient() {
+        return recipient;
+    }
+
+    public void setRecipient(String recipient) {
+        this.recipient = recipient;
+    }
+
+    public LocalDateTime getSentAt() {
+        return sentAt;
+    }
+
+    public void setSentAt(LocalDateTime sentAt) {
+        this.sentAt = sentAt;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+
+    public InputMessage(String sender, String recipient, LocalDateTime sentAt, String message) {
+        this.sender = sender;
+        this.recipient = recipient;
+        this.sentAt = sentAt;
+        this.message = message;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        InputMessage message1 = (InputMessage) o;
+        return Objects.equal(sender, message1.sender) &&
+                Objects.equal(recipient, message1.recipient) &&
+                Objects.equal(sentAt, message1.sentAt) &&
+                Objects.equal(message, message1.message);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(sender, recipient, sentAt, message);
+    }
+}

libraries/src/main/java/com/baeldung/flink/operator/BackupAggregator.java

@@ -0,0 +1,34 @@
+package com.baeldung.flink.operator;
+
+import com.baeldung.flink.model.Backup;
+import com.baeldung.flink.model.InputMessage;
+import org.apache.flink.api.common.functions.AggregateFunction;
+
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+
+    public class BackupAggregator implements AggregateFunction<InputMessage, List<InputMessage>, Backup> {
+        @Override
+        public List<InputMessage> createAccumulator() {
+            return new ArrayList<>();
+        }
+
+        @Override
+        public List<InputMessage> add(InputMessage inputMessage, List<InputMessage> inputMessages) {
+            inputMessages.add(inputMessage);
+            return inputMessages;
+        }
+
+        @Override
+        public Backup getResult(List<InputMessage> inputMessages) {
+            Backup backup = new Backup(inputMessages, LocalDateTime.now());
+                return backup;
+        }
+
+        @Override
+        public List<InputMessage> merge(List<InputMessage> inputMessages, List<InputMessage> acc1) {
+            inputMessages.addAll(acc1);
+            return inputMessages;
+        }
+    }

libraries/src/main/java/com/baeldung/flink/operator/InputMessageTimestampAssigner.java

@@ -0,0 +1,23 @@
+package com.baeldung.flink.operator;
+
+import com.baeldung.flink.model.InputMessage;
+import org.apache.flink.streaming.api.functions.AssignerWithPunctuatedWatermarks;
+import org.apache.flink.streaming.api.watermark.Watermark;
+
+import javax.annotation.Nullable;
+import java.time.ZoneId;
+
+public class InputMessageTimestampAssigner implements AssignerWithPunctuatedWatermarks<InputMessage> {
+
+    @Override
+    public long extractTimestamp(InputMessage element, long previousElementTimestamp) {
+        ZoneId zoneId = ZoneId.systemDefault();
+        return element.getSentAt().atZone(zoneId).toEpochSecond() * 1000;
+    }
+
+    @Nullable
+    @Override
+    public Watermark checkAndGetNextWatermark(InputMessage lastElement, long extractedTimestamp) {
+        return new Watermark(extractedTimestamp - 15);
+    }
+}

libraries/src/main/java/com/baeldung/flink/operator/WordsCapitalizer.java

@@ -0,0 +1,11 @@
+package com.baeldung.flink.operator;
+
+import org.apache.flink.api.common.functions.MapFunction;
+
+public class WordsCapitalizer implements MapFunction<String, String> {
+
+    @Override
+    public String map(String s) {
+        return s.toUpperCase();
+    }
+}

libraries/src/main/java/com/baeldung/flink/schema/BackupSerializationSchema.java

@@ -0,0 +1,33 @@
+package com.baeldung.flink.schema;
+
+import com.baeldung.flink.model.Backup;
+import com.fasterxml.jackson.annotation.JsonAutoDetect;
+import com.fasterxml.jackson.annotation.PropertyAccessor;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.apache.flink.api.common.serialization.SerializationSchema;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class BackupSerializationSchema
+  implements SerializationSchema<Backup> {
+
+    static ObjectMapper objectMapper = new ObjectMapper().registerModule(new JavaTimeModule());
+
+    Logger logger = LoggerFactory.getLogger(BackupSerializationSchema.class);
+
+    @Override
+    public byte[] serialize(Backup backupMessage) {
+        if(objectMapper == null) {
+            objectMapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);
+            objectMapper = new ObjectMapper().registerModule(new JavaTimeModule());
+        }
+        try {
+            String json = objectMapper.writeValueAsString(backupMessage);
+            return json.getBytes();
+        } catch (com.fasterxml.jackson.core.JsonProcessingException e) {
+            logger.error("Failed to parse JSON", e);
+        }
+        return new byte[0];
+    }
+}

libraries/src/main/java/com/baeldung/flink/schema/InputMessageDeserializationSchema.java

@@ -0,0 +1,34 @@
+package com.baeldung.flink.schema;
+
+import com.baeldung.flink.model.InputMessage;
+import com.fasterxml.jackson.annotation.JsonAutoDetect;
+import com.fasterxml.jackson.annotation.PropertyAccessor;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.apache.flink.api.common.serialization.DeserializationSchema;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+
+import java.io.IOException;
+
+public class InputMessageDeserializationSchema implements
+      DeserializationSchema<InputMessage> {
+
+    static ObjectMapper objectMapper = new ObjectMapper().registerModule(new JavaTimeModule());
+
+
+    @Override
+    public InputMessage deserialize(byte[] bytes) throws IOException {
+
+        return objectMapper.readValue(bytes, InputMessage.class);
+    }
+
+    @Override
+    public boolean isEndOfStream(InputMessage inputMessage) {
+        return false;
+    }
+
+    @Override
+    public TypeInformation<InputMessage> getProducedType() {
+        return TypeInformation.of(InputMessage.class);
+    }
+}

libraries/src/test/java/com/baeldung/flink/BackupCreatorIntegrationTest.java

@@ -0,0 +1,103 @@
+package com.baeldung.flink;
+
+import com.baeldung.flink.model.Backup;
+import com.baeldung.flink.model.InputMessage;
+import com.baeldung.flink.operator.BackupAggregator;
+import com.baeldung.flink.operator.InputMessageTimestampAssigner;
+import com.baeldung.flink.schema.BackupSerializationSchema;
+import com.baeldung.flink.schema.InputMessageDeserializationSchema;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.apache.commons.collections.ListUtils;
+import org.apache.flink.api.common.serialization.DeserializationSchema;
+import org.apache.flink.api.common.serialization.SerializationSchema;
+import org.apache.flink.streaming.api.TimeCharacteristic;
+import org.apache.flink.streaming.api.datastream.DataStreamSource;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.sink.SinkFunction;
+import org.apache.flink.streaming.api.windowing.time.Time;
+import org.awaitility.Awaitility;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+
+public class BackupCreatorIntegrationTest {
+    public static ObjectMapper mapper;
+
+    @Before
+    public void setup() {
+        mapper = new ObjectMapper().registerModule(new JavaTimeModule());
+    }
+
+    @Test
+    public void givenProperJson_whenDeserializeIsInvoked_thenProperObjectIsReturned() throws IOException {
+        InputMessage message = new InputMessage("Me", "User", LocalDateTime.now(), "Test Message");
+        byte[] messageSerialized = mapper.writeValueAsBytes(message);
+        DeserializationSchema<InputMessage> deserializationSchema = new InputMessageDeserializationSchema();
+        InputMessage messageDeserialized = deserializationSchema.deserialize(messageSerialized);
+
+        assertEquals(message, messageDeserialized);
+    }
+
+    @Test
+    public void givenMultipleInputMessagesFromDifferentDays_whenBackupCreatorIsUser_thenMessagesAreGroupedProperly() throws Exception {
+        LocalDateTime currentTime = LocalDateTime.now();
+        InputMessage message = new InputMessage("Me", "User", currentTime, "First TestMessage");
+        InputMessage secondMessage = new InputMessage("Me", "User", currentTime.plusHours(1), "First TestMessage");
+        InputMessage thirdMessage = new InputMessage("Me", "User", currentTime.plusHours(2), "First TestMessage");
+        InputMessage fourthMessage = new InputMessage("Me", "User", currentTime.plusHours(3), "First TestMessage");
+        InputMessage fifthMessage = new InputMessage("Me", "User", currentTime.plusHours(25), "First TestMessage");
+        InputMessage sixthMessage = new InputMessage("Me", "User", currentTime.plusHours(26), "First TestMessage");
+
+        List<InputMessage> firstBackupMessages = Arrays.asList(message, secondMessage, thirdMessage, fourthMessage);
+        List<InputMessage> secondBackupMessages = Arrays.asList(fifthMessage, sixthMessage);
+        List<InputMessage> inputMessages = ListUtils.union(firstBackupMessages, secondBackupMessages);
+
+        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
+        env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
+        env.setParallelism(1);
+        DataStreamSource<InputMessage> testDataSet = env.fromCollection(inputMessages);
+        CollectingSink sink = new CollectingSink();
+        testDataSet.assignTimestampsAndWatermarks(new InputMessageTimestampAssigner())
+          .timeWindowAll(Time.hours(24))
+          .aggregate(new BackupAggregator())
+          .addSink(sink);
+
+        env.execute();
+
+        Awaitility.await().until(() ->  sink.backups.size() == 2);
+        assertEquals(2, sink.backups.size());
+        assertEquals(firstBackupMessages, sink.backups.get(0).getInputMessages());
+        assertEquals(secondBackupMessages, sink.backups.get(1).getInputMessages());
+
+    }
+
+    @Test
+    public void givenProperBackupObject_whenSerializeIsInvoked_thenObjectIsProperlySerialized() throws IOException {
+        InputMessage message = new InputMessage("Me", "User", LocalDateTime.now(), "Test Message");
+        List<InputMessage> messages = Arrays.asList(message);
+        Backup backup = new Backup(messages, LocalDateTime.now());
+        byte[] backupSerialized = mapper.writeValueAsBytes(backup);
+        SerializationSchema<Backup> serializationSchema = new BackupSerializationSchema();
+        byte[] backupProcessed = serializationSchema.serialize(backup);
+        
+        assertEquals(backupSerialized, backupProcessed);
+    }
+
+    private static class CollectingSink implements SinkFunction<Backup> {
+        
+        public static List<Backup> backups = new ArrayList<>();
+
+        @Override
+        public synchronized void invoke(Backup value, Context context) throws Exception {
+            backups.add(value);
+        }
+    }
+}

libraries/src/test/java/com/baeldung/flink/WordCapitalizerIntegrationTest.java

@@ -0,0 +1,34 @@
+package com.baeldung.flink;
+
+import com.baeldung.flink.operator.WordsCapitalizer;
+import org.apache.flink.api.java.DataSet;
+import org.apache.flink.api.java.ExecutionEnvironment;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class WordCapitalizerIntegrationTest {
+
+    @Test
+    public void givenDataSet_whenExecuteWordCapitalizer_thenReturnCapitalizedWords() throws Exception {
+        ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
+        List<String> data = Arrays.asList("dog", "cat", "wolf", "pig");
+
+         DataSet<String> testDataSet = env.fromCollection(data);
+
+
+        List<String> dataProcessed = testDataSet
+          .map(new WordsCapitalizer())
+          .collect();
+
+        List<String> testDataCapitalized = data.stream()
+          .map(String::toUpperCase)
+          .collect(Collectors.toList());
+
+        Assert.assertEquals(testDataCapitalized, dataProcessed);
+    }
+
+}

optaplanner/pom.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>optaplanner</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.optaplanner</groupId>
+            <artifactId>optaplanner-core</artifactId>
+            <version>7.9.0.Final</version>
+        </dependency>
+
+        <!--<dependency>-->
+            <!--<groupId></groupId>-->
+            <!--<artifactId></artifactId>-->
+        <!--</dependency>-->
+    </dependencies>
+
+</project>

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

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

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

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

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

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