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;
-        float b1 = 0;
-        float m2 = 1;
-        float b2 = -1;
+        double m1 = 0;
+        double b1 = 0;
+        double m2 = 1;
+        double b2 = -1;
 
         Optional<Point> point = service.calculateIntersectionPoint(m1, b1, m2, b2);
 
         assertTrue(point.isPresent());
-        assertEquals(point.get().x, 1);
-        assertEquals(point.get().y, 0);
+        assertEquals(point.get().getX(), 1, 0.001);
+        assertEquals(point.get().getY(), 0, 0.001);
     }
 
     @Test
     public void givenParallelLines_whenCalculatePoint_thenEmpty() {
-        float m1 = 1;
-        float b1 = 0;
-        float m2 = 1;
-        float b2 = -1;
+        double m1 = 1;
+        double b1 = 0;
+        double m2 = 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() {
-        String currentTime = dateFormat.format(calendar.getTime());
-        assertThat(imageFileProcessor.openFile("file1.png")).isEqualTo("Opening PNG file file1.png at: " + currentTime);
+    public void givenImageProcessorInstance_whenCalledopenFile_thenOneAssertion() throws ParseException {
+        LocalTime currentTime = LocalTime.now();
+
+        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() {
-        String currentTime = dateFormat.format(calendar.getTime());
-        assertThat(imageFileProcessor.editFile("file1.png")).isEqualTo("Editing PNG file file1.png at: " + currentTime);
+    public void givenImageProcessorInstance_whenCallededitFile_thenOneAssertion() throws ParseException {
+        LocalTime currentTime = LocalTime.now();
+
+        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() {
-        String currentTime = dateFormat.format(calendar.getTime());
-        assertThat(imageFileProcessor.writeFile("file1.png")).isEqualTo("Writing PNG file file1.png at: " + currentTime);
+    public void givenImageProcessorInstance_whenCalledwriteFile_thenOneAssertion() throws ParseException {
+        LocalTime currentTime = LocalTime.now();
+
+        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() {
-        String currentTime = dateFormat.format(calendar.getTime());
-        assertThat(imageFileProcessor.saveFile("file1.png")).isEqualTo("Saving PNG file file1.png at: " + currentTime);
+    public void givenImageProcessorInstance_whenCalledsaveFile_thenOneAssertion() throws ParseException {
+        LocalTime currentTime = LocalTime.now();
+
+        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 <[email protected]>
  */
 public class NullSafeCollectionStreamsUsingJava8OptionalContainerUnitTest {
-    
-    private final NullSafeCollectionStreamsUsingJava8OptionalContainer instance = 
-            new NullSafeCollectionStreamsUsingJava8OptionalContainer();
+
+    private final NullSafeCollectionStreamsUsingJava8OptionalContainer instance = 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 org.junit.Test;
+import static org.junit.Assert.assertEquals;
+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;
+    }
+
+}