Merge branch 'master' of https://github.com/eugenp/tutorials

algorithms/src/main/java/com/baeldung/algorithms/BinarySearch.java

@@ -1,11 +1,11 @@
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
 public class BinarySearch {
 
-    public int runBinarySearch() {
-        int[] sortedArray = { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
-        int key = 6;
+    public int runBinarySearchIteratively(int[] sortedArray, int key, int low, int high) {
 
-        int low = 0;
-        int high = sortedArray.length - 1;
         int index = Integer.MAX_VALUE;
 
         while (low <= high) {
@@ -23,4 +23,31 @@ public class BinarySearch {
         }
         return index;
     }
+
+    public int runBinarySearchRecursively(int[] sortedArray, int key, int low, int high) {
+
+        int middle = (low + high) / 2;
+        if (high < low) {
+            return -1;
+        }
+
+        if (key == sortedArray[middle]) {
+          return middle;
+        } else if (key < sortedArray[middle]) {
+          return runBinarySearchRecursively(sortedArray, key, low, middle - 1);
+        } else {
+          return runBinarySearchRecursively(sortedArray, key, middle + 1, high);
+        }
+    }
+
+    public int runBinarySearchUsingJavaArrays(int[] sortedArray, Integer key) {
+        int index = Arrays.binarySearch(sortedArray, key);
+        return index;
+    }
+
+    public int runBinarySearchUsingJavaCollections(List<Integer> sortedList, Integer key) {
+        int index = Collections.binarySearch(sortedList, key);
+        return index;
+    }
+
 }

algorithms/src/test/java/algorithms/BinarySearchTest.java

@@ -1,14 +1,41 @@
+import java.util.Arrays;
+import java.util.List;
+
 import org.junit.Assert;
 import org.junit.Test;
 
 
 public class BinarySearchTest {
 
+    int[] sortedArray = { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
+    int key = 6;
+    int expectedIndexForSearchKey = 7;
+    int low = 0;
+    int high = sortedArray.length - 1;
+    List<Integer> sortedList = Arrays.asList(0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9);
+    
     @Test
-    public void givenASortedArrayOfIntegers_whenBinarySearchRunForANumber_thenGetIndexOfTheNumber() {
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunIterativelyForANumber_thenGetIndexOfTheNumber() {
         BinarySearch binSearch = new BinarySearch();
-        int expectedIndexForSearchKey = 7;
-        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearch());
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchIteratively(sortedArray, key, low, high));
     }
 
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunRecursivelyForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchRecursively(sortedArray, key, low, high));
+    }
+    
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunUsingArraysClassStaticMethodForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchUsingJavaArrays(sortedArray, key));
+    }
+    
+    @Test
+    public void givenASortedListOfIntegers_whenBinarySearchRunUsingCollectionsClassStaticMethodForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchUsingJavaCollections(sortedList, key));
+    }
+    
 }

asciidoctor/README.md

@@ -1,3 +1,4 @@
 ### Relevant articles
 
-- [Introduction to Asciidoctor](http://www.baeldung.com/introduction-to-asciidoctor)
+- [Introduction to Asciidoctor](http://www.baeldung.com/introduction-to-asciidoctor)
+- [Generating a Book with Asciidoctor](http://www.baeldung.com/asciidoctor-book)

core-java/src/main/java/com/baeldung/concurrent/blockingqueue/NumbersProducer.java

@@ -19,13 +19,15 @@ public class NumbersProducer implements Runnable {
         try {
             generateNumbers();
         } catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
+            Thread.currentThread()
+                .interrupt();
         }
     }
 
     private void generateNumbers() throws InterruptedException {
         for (int i = 0; i < 100; i++) {
-            numbersQueue.put(ThreadLocalRandom.current().nextInt(100));
+            numbersQueue.put(ThreadLocalRandom.current()
+                .nextInt(100));
         }
         for (int j = 0; j < poisonPillPerProducer; j++) {
             numbersQueue.put(poisonPill);

core-java/src/main/java/com/baeldung/concurrent/delayqueue/DelayObject.java

@@ -27,9 +27,6 @@ public class DelayObject implements Delayed {
 
     @Override
     public String toString() {
-        return "{" +
-                "data='" + data + '\'' +
-                ", startTime=" + startTime +
-                '}';
+        return "{" + "data='" + data + '\'' + ", startTime=" + startTime + '}';
     }
 }

core-java/src/main/java/com/baeldung/designpatterns/adapter/LuxuryCarsSpeed.java

@@ -4,11 +4,11 @@ public class LuxuryCarsSpeed {
     public double bugattiVeyronInMPH() {
         return 268;
     }
-    
+
     public double mcLarenInMPH() {
         return 241;
     }
-    
+
     public double astonMartinInMPH() {
         return 220;
     }

core-java/src/main/java/com/baeldung/designpatterns/adapter/LuxuryCarsSpeedAdapter.java

@@ -2,6 +2,8 @@ package com.baeldung.designpatterns.adapter;
 
 public interface LuxuryCarsSpeedAdapter {
     public double bugattiVeyronInKMPH();
+
     public double mcLarenInKMPH();
+
     public double astonMartinInKMPH();
 }

core-java/src/main/java/com/baeldung/designpatterns/bridge/Blue.java

@@ -5,7 +5,7 @@ import static com.baeldung.designpatterns.util.LogerUtil.LOG;
 public class Blue implements Color {
 
     @Override
-    public void fillColor() { 
+    public void fillColor() {
         LOG.info("Color : Blue");
     }
 

core-java/src/main/java/com/baeldung/designpatterns/decorator/DecoratorPatternDriver.java

@@ -5,16 +5,14 @@ import static com.baeldung.designpatterns.util.LogerUtil.LOG;
 public class DecoratorPatternDriver {
 
     public static void main(String[] args) {
-        //christmas tree with just one Garland
+        // christmas tree with just one Garland
         ChristmasTree tree1 = new Garland(new ChristmasTreeImpl());
         LOG.info(tree1.decorate());
-        
-        //christmas tree with two Garlands and one Bubble lights
-        ChristmasTree tree2 = new BubbleLights(new Garland(
-          new Garland(new ChristmasTreeImpl()))
-        );
+
+        // christmas tree with two Garlands and one Bubble lights
+        ChristmasTree tree2 = new BubbleLights(new Garland(new Garland(new ChristmasTreeImpl())));
         LOG.info(tree2.decorate());
-        
+
     }
 
 }

core-java/src/main/java/com/baeldung/designpatterns/proxy/ExpensiveObjectImpl.java

@@ -7,14 +7,14 @@ public class ExpensiveObjectImpl implements ExpensiveObject {
     public ExpensiveObjectImpl() {
         heavyInitialConfiguration();
     }
-    
+
     @Override
     public void process() {
         LOG.info("processing complete.");
     }
-    
+
     private void heavyInitialConfiguration() {
         LOG.info("Loading initial configuration...");
     }
-    
+
 }

core-java/src/main/java/com/baeldung/forkjoin/CustomRecursiveAction.java

@@ -43,6 +43,7 @@ public class CustomRecursiveAction extends RecursiveAction {
 
     private void processing(String work) {
         String result = work.toUpperCase();
-        logger.info("This result - (" + result + ") - was processed by " + Thread.currentThread().getName());
+        logger.info("This result - (" + result + ") - was processed by " + Thread.currentThread()
+            .getName());
     }
 }

core-java/src/main/java/com/baeldung/java/reflection/Greeter.java

@@ -5,6 +5,6 @@ import java.lang.annotation.RetentionPolicy;
 
 @Retention(RetentionPolicy.RUNTIME)
 public @interface Greeter {
-    
-    public String greet() default ""; 
+
+    public String greet() default "";
 }

core-java/src/main/java/com/baeldung/map/iteration/MapIteration.java

@@ -44,7 +44,8 @@ public class MapIteration {
     }
 
     public void iterateUsingIteratorAndEntry(Map<String, Integer> map) {
-        Iterator<Map.Entry<String, Integer>> iterator = map.entrySet().iterator();
+        Iterator<Map.Entry<String, Integer>> iterator = map.entrySet()
+            .iterator();
         while (iterator.hasNext()) {
             Map.Entry<String, Integer> pair = iterator.next();
             System.out.println(pair.getKey() + ":" + pair.getValue());
@@ -58,7 +59,9 @@ public class MapIteration {
     }
 
     public void iterateUsingStreamAPI(Map<String, Integer> map) {
-        map.entrySet().stream().forEach(e -> System.out.println(e.getKey() + ":" + e.getValue()));
+        map.entrySet()
+            .stream()
+            .forEach(e -> System.out.println(e.getKey() + ":" + e.getValue()));
     }
 
     public void iterateKeys(Map<String, Integer> map) {

core-java/src/main/java/com/baeldung/maths/BigIntegerImpl.java

@@ -8,7 +8,7 @@ public class BigIntegerImpl {
 
         BigInteger numStarsMilkyWay = new BigInteger("8731409320171337804361260816606476");
         BigInteger numStarsAndromeda = new BigInteger("5379309320171337804361260816606476");
-        
+
         BigInteger totalStars = numStarsMilkyWay.add(numStarsAndromeda);
 
     }

core-java/src/main/java/com/baeldung/networking/cookies/PersistentCookieStore.java

@@ -9,7 +9,8 @@ public class PersistentCookieStore implements CookieStore, Runnable {
     public PersistentCookieStore() {
         store = new CookieManager().getCookieStore();
         // deserialize cookies into store
-        Runtime.getRuntime().addShutdownHook(new Thread(this));
+        Runtime.getRuntime()
+            .addShutdownHook(new Thread(this));
     }
 
     @Override

core-java/src/main/java/com/baeldung/printscreen/Screenshot.java

@@ -14,7 +14,8 @@ public class Screenshot {
     }
 
     public void getScreenshot(int timeToWait) throws Exception {
-        Rectangle rectangle = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());
+        Rectangle rectangle = new Rectangle(Toolkit.getDefaultToolkit()
+            .getScreenSize());
         Robot robot = new Robot();
         BufferedImage img = robot.createScreenCapture(rectangle);
         ImageIO.write(img, "jpg", new File(path));

core-java/src/main/java/com/baeldung/uuid/UUIDGenerator.java

@@ -6,16 +6,16 @@ import java.security.NoSuchAlgorithmException;
 import java.util.UUID;
 
 public class UUIDGenerator {
-    
+
     /**
      * These are predefined UUID for name spaces
      */
-    private static final String NAMESPACE_DNS   = "6ba7b810-9dad-11d1-80b4-00c04fd430c8";
-    private static final String NAMESPACE_URL   = "6ba7b811-9dad-11d1-80b4-00c04fd430c8";
-    private static final String NAMESPACE_OID   = "6ba7b812-9dad-11d1-80b4-00c04fd430c8";
-    private static final String NAMESPACE_X500  = "6ba7b814-9dad-11d1-80b4-00c04fd430c8";
+    private static final String NAMESPACE_DNS = "6ba7b810-9dad-11d1-80b4-00c04fd430c8";
+    private static final String NAMESPACE_URL = "6ba7b811-9dad-11d1-80b4-00c04fd430c8";
+    private static final String NAMESPACE_OID = "6ba7b812-9dad-11d1-80b4-00c04fd430c8";
+    private static final String NAMESPACE_X500 = "6ba7b814-9dad-11d1-80b4-00c04fd430c8";
 
-    private static final  char[] hexArray = "0123456789ABCDEF".toCharArray();
+    private static final char[] hexArray = "0123456789ABCDEF".toCharArray();
 
     public static void main(String[] args) {
         try {
@@ -35,7 +35,7 @@ public class UUIDGenerator {
         UUID uuid = UUID.randomUUID();
         return uuid;
     }
-    
+
     /**
      * Type 3 UUID Generation
      * 
@@ -47,7 +47,7 @@ public class UUIDGenerator {
         UUID uuid = UUID.nameUUIDFromBytes(bytes);
         return uuid;
     }
-    
+
     /**
      * Type 5 UUID Generation
      * 
@@ -59,8 +59,7 @@ public class UUIDGenerator {
         UUID uuid = type5UUIDFromBytes(bytes);
         return uuid;
     }
-    
-    
+
     public static UUID type5UUIDFromBytes(byte[] name) {
         MessageDigest md;
         try {
@@ -69,27 +68,26 @@ public class UUIDGenerator {
             throw new InternalError("MD5 not supported", nsae);
         }
         byte[] bytes = md.digest(name);
-        bytes[6]  &= 0x0f;  /* clear version        */
-        bytes[6]  |= 0x50;  /* set to version 5     */
-        bytes[8]  &= 0x3f;  /* clear variant        */
-        bytes[8]  |= 0x80;  /* set to IETF variant  */
+        bytes[6] &= 0x0f; /* clear version        */
+        bytes[6] |= 0x50; /* set to version 5     */
+        bytes[8] &= 0x3f; /* clear variant        */
+        bytes[8] |= 0x80; /* set to IETF variant  */
         return constructType5UUID(bytes);
     }
-    
+
     private static UUID constructType5UUID(byte[] data) {
         long msb = 0;
         long lsb = 0;
         assert data.length == 16 : "data must be 16 bytes in length";
-        
-        for (int i=0; i<8; i++)
+
+        for (int i = 0; i < 8; i++)
             msb = (msb << 8) | (data[i] & 0xff);
-        
-        for (int i=8; i<16; i++)
+
+        for (int i = 8; i < 16; i++)
             lsb = (lsb << 8) | (data[i] & 0xff);
         return new UUID(msb, lsb);
     }
 
-    
     /**
      * Unique Keys Generation Using Message Digest and Type 4 UUID
      * 

core-java/src/test/java/com/baeldung/completablefuture/CompletableFutureLongRunningUnitTest.java

@@ -15,7 +15,6 @@ public class CompletableFutureLongRunningUnitTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(CompletableFutureLongRunningUnitTest.class);
 
-
     @Test
     public void whenRunningCompletableFutureAsynchronously_thenGetMethodWaitsForResult() throws InterruptedException, ExecutionException {
         Future<String> completableFuture = calculateAsync();
@@ -27,11 +26,12 @@ public class CompletableFutureLongRunningUnitTest {
     private Future<String> calculateAsync() throws InterruptedException {
         CompletableFuture<String> completableFuture = new CompletableFuture<>();
 
-        Executors.newCachedThreadPool().submit(() -> {
-            Thread.sleep(500);
-            completableFuture.complete("Hello");
-            return null;
-        });
+        Executors.newCachedThreadPool()
+            .submit(() -> {
+                Thread.sleep(500);
+                completableFuture.complete("Hello");
+                return null;
+            });
 
         return completableFuture;
     }
@@ -47,11 +47,12 @@ public class CompletableFutureLongRunningUnitTest {
     private Future<String> calculateAsyncWithCancellation() throws InterruptedException {
         CompletableFuture<String> completableFuture = new CompletableFuture<>();
 
-        Executors.newCachedThreadPool().submit(() -> {
-            Thread.sleep(500);
-            completableFuture.cancel(false);
-            return null;
-        });
+        Executors.newCachedThreadPool()
+            .submit(() -> {
+                Thread.sleep(500);
+                completableFuture.cancel(false);
+                return null;
+            });
 
         return completableFuture;
     }
@@ -98,21 +99,24 @@ public class CompletableFutureLongRunningUnitTest {
 
     @Test
     public void whenUsingThenCompose_thenFuturesExecuteSequentially() throws ExecutionException, InterruptedException {
-        CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> "Hello").thenCompose(s -> CompletableFuture.supplyAsync(() -> s + " World"));
+        CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> "Hello")
+            .thenCompose(s -> CompletableFuture.supplyAsync(() -> s + " World"));
 
         assertEquals("Hello World", completableFuture.get());
     }
 
     @Test
     public void whenUsingThenCombine_thenWaitForExecutionOfBothFutures() throws ExecutionException, InterruptedException {
-        CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> "Hello").thenCombine(CompletableFuture.supplyAsync(() -> " World"), (s1, s2) -> s1 + s2);
+        CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> "Hello")
+            .thenCombine(CompletableFuture.supplyAsync(() -> " World"), (s1, s2) -> s1 + s2);
 
         assertEquals("Hello World", completableFuture.get());
     }
 
     @Test
     public void whenUsingThenAcceptBoth_thenWaitForExecutionOfBothFutures() throws ExecutionException, InterruptedException {
-        CompletableFuture.supplyAsync(() -> "Hello").thenAcceptBoth(CompletableFuture.supplyAsync(() -> " World"), (s1, s2) -> LOG.debug(s1 + s2));
+        CompletableFuture.supplyAsync(() -> "Hello")
+            .thenAcceptBoth(CompletableFuture.supplyAsync(() -> " World"), (s1, s2) -> LOG.debug(s1 + s2));
     }
 
     @Test
@@ -131,7 +135,9 @@ public class CompletableFutureLongRunningUnitTest {
         assertTrue(future2.isDone());
         assertTrue(future3.isDone());
 
-        String combined = Stream.of(future1, future2, future3).map(CompletableFuture::join).collect(Collectors.joining(" "));
+        String combined = Stream.of(future1, future2, future3)
+            .map(CompletableFuture::join)
+            .collect(Collectors.joining(" "));
 
         assertEquals("Hello Beautiful World", combined);
     }
@@ -147,7 +153,8 @@ public class CompletableFutureLongRunningUnitTest {
                 throw new RuntimeException("Computation error!");
             }
             return "Hello, " + name;
-        }).handle((s, t) -> s != null ? s : "Hello, Stranger!");
+        })
+            .handle((s, t) -> s != null ? s : "Hello, Stranger!");
 
         assertEquals("Hello, Stranger!", completableFuture.get());
     }

core-java/src/test/java/com/baeldung/datetime/UseLocalDateTimeUnitTest.java

@@ -15,7 +15,9 @@ public class UseLocalDateTimeUnitTest {
 
     @Test
     public void givenString_whenUsingParse_thenLocalDateTime() {
-        assertEquals(LocalDate.of(2016, Month.MAY, 10), useLocalDateTime.getLocalDateTimeUsingParseMethod("2016-05-10T06:30").toLocalDate());
-        assertEquals(LocalTime.of(6, 30), useLocalDateTime.getLocalDateTimeUsingParseMethod("2016-05-10T06:30").toLocalTime());
+        assertEquals(LocalDate.of(2016, Month.MAY, 10), useLocalDateTime.getLocalDateTimeUsingParseMethod("2016-05-10T06:30")
+            .toLocalDate());
+        assertEquals(LocalTime.of(6, 30), useLocalDateTime.getLocalDateTimeUsingParseMethod("2016-05-10T06:30")
+            .toLocalTime());
     }
 }

core-java/src/test/java/com/baeldung/datetime/UseLocalDateUnitTest.java

@@ -15,12 +15,14 @@ public class UseLocalDateUnitTest {
 
     @Test
     public void givenValues_whenUsingFactoryOf_thenLocalDate() {
-        assertEquals("2016-05-10", useLocalDate.getLocalDateUsingFactoryOfMethod(2016, 5, 10).toString());
+        assertEquals("2016-05-10", useLocalDate.getLocalDateUsingFactoryOfMethod(2016, 5, 10)
+            .toString());
     }
 
     @Test
     public void givenString_whenUsingParse_thenLocalDate() {
-        assertEquals("2016-05-10", useLocalDate.getLocalDateUsingParseMethod("2016-05-10").toString());
+        assertEquals("2016-05-10", useLocalDate.getLocalDateUsingParseMethod("2016-05-10")
+            .toString());
     }
 
     @Test
@@ -30,12 +32,14 @@ public class UseLocalDateUnitTest {
 
     @Test
     public void givenDate_whenUsingPlus_thenNextDay() {
-        assertEquals(LocalDate.now().plusDays(1), useLocalDate.getNextDay(LocalDate.now()));
+        assertEquals(LocalDate.now()
+            .plusDays(1), useLocalDate.getNextDay(LocalDate.now()));
     }
 
     @Test
     public void givenDate_whenUsingMinus_thenPreviousDay() {
-        assertEquals(LocalDate.now().minusDays(1), useLocalDate.getPreviousDay(LocalDate.now()));
+        assertEquals(LocalDate.now()
+            .minusDays(1), useLocalDate.getPreviousDay(LocalDate.now()));
     }
 
     @Test
@@ -45,7 +49,8 @@ public class UseLocalDateUnitTest {
 
     @Test
     public void givenToday_whenUsingWithTemporalAdjuster_thenFirstDayOfMonth() {
-        assertEquals(1, useLocalDate.getFirstDayOfMonth().getDayOfMonth());
+        assertEquals(1, useLocalDate.getFirstDayOfMonth()
+            .getDayOfMonth());
     }
 
     @Test

core-java/src/test/java/com/baeldung/functionalinterface/FunctionalInterfaceUnitTest.java

@@ -21,7 +21,6 @@ public class FunctionalInterfaceUnitTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(FunctionalInterfaceUnitTest.class);
 
-
     @Test
     public void whenPassingLambdaToComputeIfAbsent_thenTheValueGetsComputedAndPutIntoMap() {
         Map<String, Integer> nameMap = new HashMap<>();
@@ -83,7 +82,8 @@ public class FunctionalInterfaceUnitTest {
             return result;
         });
 
-        List<Integer> fibonacci5 = fibonacci.limit(5).collect(Collectors.toList());
+        List<Integer> fibonacci5 = fibonacci.limit(5)
+            .collect(Collectors.toList());
 
         assertEquals(new Integer(1), fibonacci5.get(0));
         assertEquals(new Integer(1), fibonacci5.get(1));
@@ -112,7 +112,9 @@ public class FunctionalInterfaceUnitTest {
     public void whenUsingPredicateInFilter_thenListValuesAreFilteredOut() {
         List<String> names = Arrays.asList("Angela", "Aaron", "Bob", "Claire", "David");
 
-        List<String> namesWithA = names.stream().filter(name -> name.startsWith("A")).collect(Collectors.toList());
+        List<String> namesWithA = names.stream()
+            .filter(name -> name.startsWith("A"))
+            .collect(Collectors.toList());
 
         assertEquals(2, namesWithA.size());
         assertTrue(namesWithA.contains("Angela"));
@@ -135,7 +137,8 @@ public class FunctionalInterfaceUnitTest {
 
         List<Integer> values = Arrays.asList(3, 5, 8, 9, 12);
 
-        int sum = values.stream().reduce(0, (i1, i2) -> i1 + i2);
+        int sum = values.stream()
+            .reduce(0, (i1, i2) -> i1 + i2);
 
         assertEquals(37, sum);
 

core-java/src/test/java/com/baeldung/java/concurrentmap/ConcurrentMapAggregateStatusManualTest.java

@@ -47,7 +47,8 @@ public class ConcurrentMapAggregateStatusManualTest {
         executorService.awaitTermination(1, TimeUnit.MINUTES);
 
         for (int i = 1; i <= MAX_SIZE; i++) {
-            assertEquals("map size should be consistently reliable", i, mapSizes.get(i - 1).intValue());
+            assertEquals("map size should be consistently reliable", i, mapSizes.get(i - 1)
+                .intValue());
         }
         assertEquals(MAX_SIZE, concurrentMap.size());
     }
@@ -69,7 +70,8 @@ public class ConcurrentMapAggregateStatusManualTest {
         executorService.shutdown();
         executorService.awaitTermination(1, TimeUnit.MINUTES);
 
-        assertNotEquals("map size collected with concurrent updates not reliable", MAX_SIZE, mapSizes.get(MAX_SIZE - 1).intValue());
+        assertNotEquals("map size collected with concurrent updates not reliable", MAX_SIZE, mapSizes.get(MAX_SIZE - 1)
+            .intValue());
         assertEquals(MAX_SIZE, concurrentMap.size());
     }
 

core-java/src/test/java/com/baeldung/java/concurrentmap/ConcurretMapMemoryConsistencyManualTest.java

@@ -16,8 +16,12 @@ public class ConcurretMapMemoryConsistencyManualTest {
     public void givenConcurrentMap_whenSumParallel_thenCorrect() throws Exception {
         Map<String, Integer> map = new ConcurrentHashMap<>();
         List<Integer> sumList = parallelSum100(map, 1000);
-        assertEquals(1, sumList.stream().distinct().count());
-        long wrongResultCount = sumList.stream().filter(num -> num != 100).count();
+        assertEquals(1, sumList.stream()
+            .distinct()
+            .count());
+        long wrongResultCount = sumList.stream()
+            .filter(num -> num != 100)
+            .count();
         assertEquals(0, wrongResultCount);
     }
 
@@ -25,8 +29,12 @@ public class ConcurretMapMemoryConsistencyManualTest {
     public void givenHashtable_whenSumParallel_thenCorrect() throws Exception {
         Map<String, Integer> map = new Hashtable<>();
         List<Integer> sumList = parallelSum100(map, 1000);
-        assertEquals(1, sumList.stream().distinct().count());
-        long wrongResultCount = sumList.stream().filter(num -> num != 100).count();
+        assertEquals(1, sumList.stream()
+            .distinct()
+            .count());
+        long wrongResultCount = sumList.stream()
+            .filter(num -> num != 100)
+            .count();
         assertEquals(0, wrongResultCount);
     }
 
@@ -34,8 +42,12 @@ public class ConcurretMapMemoryConsistencyManualTest {
     public void givenHashMap_whenSumParallel_thenError() throws Exception {
         Map<String, Integer> map = new HashMap<>();
         List<Integer> sumList = parallelSum100(map, 100);
-        assertNotEquals(1, sumList.stream().distinct().count());
-        long wrongResultCount = sumList.stream().filter(num -> num != 100).count();
+        assertNotEquals(1, sumList.stream()
+            .distinct()
+            .count());
+        long wrongResultCount = sumList.stream()
+            .filter(num -> num != 100)
+            .count();
         assertTrue(wrongResultCount > 0);
     }
 

core-java/src/test/java/com/baeldung/java8/Java8GroupingByCollectorUnitTest.java

@@ -13,35 +13,26 @@ import static org.junit.Assert.*;
 
 public class Java8GroupingByCollectorUnitTest {
 
-    private static final List<BlogPost> posts = Arrays.asList(
-      new BlogPost("News item 1", "Author 1", BlogPostType.NEWS, 15),
-      new BlogPost("Tech review 1", "Author 2", BlogPostType.REVIEW, 5),
-      new BlogPost("Programming guide", "Author 1", BlogPostType.GUIDE, 20),
-      new BlogPost("News item 2", "Author 2", BlogPostType.NEWS, 35),
-      new BlogPost("Tech review 2", "Author 1", BlogPostType.REVIEW, 15));
+    private static final List<BlogPost> posts = Arrays.asList(new BlogPost("News item 1", "Author 1", BlogPostType.NEWS, 15), new BlogPost("Tech review 1", "Author 2", BlogPostType.REVIEW, 5),
+        new BlogPost("Programming guide", "Author 1", BlogPostType.GUIDE, 20), new BlogPost("News item 2", "Author 2", BlogPostType.NEWS, 35), new BlogPost("Tech review 2", "Author 1", BlogPostType.REVIEW, 15));
 
     @Test
     public void givenAListOfPosts_whenGroupedByType_thenGetAMapBetweenTypeAndPosts() {
-        Map<BlogPostType, List<BlogPost>> postsPerType = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getType));
+        Map<BlogPostType, List<BlogPost>> postsPerType = posts.stream()
+            .collect(groupingBy(BlogPost::getType));
 
-        assertEquals(2, postsPerType
-          .get(BlogPostType.NEWS)
-          .size());
-        assertEquals(1, postsPerType
-          .get(BlogPostType.GUIDE)
-          .size());
-        assertEquals(2, postsPerType
-          .get(BlogPostType.REVIEW)
-          .size());
+        assertEquals(2, postsPerType.get(BlogPostType.NEWS)
+            .size());
+        assertEquals(1, postsPerType.get(BlogPostType.GUIDE)
+            .size());
+        assertEquals(2, postsPerType.get(BlogPostType.REVIEW)
+            .size());
     }
 
     @Test
     public void givenAListOfPosts_whenGroupedByTypeAndTheirTitlesAreJoinedInAString_thenGetAMapBetweenTypeAndCsvTitles() {
-        Map<BlogPostType, String> postsPerType = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getType, mapping(BlogPost::getTitle, joining(", ", "Post titles: [", "]"))));
+        Map<BlogPostType, String> postsPerType = posts.stream()
+            .collect(groupingBy(BlogPost::getType, mapping(BlogPost::getTitle, joining(", ", "Post titles: [", "]"))));
 
         assertEquals("Post titles: [News item 1, News item 2]", postsPerType.get(BlogPostType.NEWS));
         assertEquals("Post titles: [Programming guide]", postsPerType.get(BlogPostType.GUIDE));
@@ -50,174 +41,135 @@ public class Java8GroupingByCollectorUnitTest {
 
     @Test
     public void givenAListOfPosts_whenGroupedByTypeAndSumTheLikes_thenGetAMapBetweenTypeAndPostLikes() {
-        Map<BlogPostType, Integer> likesPerType = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getType, summingInt(BlogPost::getLikes)));
+        Map<BlogPostType, Integer> likesPerType = posts.stream()
+            .collect(groupingBy(BlogPost::getType, summingInt(BlogPost::getLikes)));
 
-        assertEquals(50, likesPerType
-          .get(BlogPostType.NEWS)
-          .intValue());
-        assertEquals(20, likesPerType
-          .get(BlogPostType.REVIEW)
-          .intValue());
-        assertEquals(20, likesPerType
-          .get(BlogPostType.GUIDE)
-          .intValue());
+        assertEquals(50, likesPerType.get(BlogPostType.NEWS)
+            .intValue());
+        assertEquals(20, likesPerType.get(BlogPostType.REVIEW)
+            .intValue());
+        assertEquals(20, likesPerType.get(BlogPostType.GUIDE)
+            .intValue());
     }
 
     @Test
     public void givenAListOfPosts_whenGroupedByTypeInAnEnumMap_thenGetAnEnumMapBetweenTypeAndPosts() {
-        EnumMap<BlogPostType, List<BlogPost>> postsPerType = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getType, () -> new EnumMap<>(BlogPostType.class), toList()));
+        EnumMap<BlogPostType, List<BlogPost>> postsPerType = posts.stream()
+            .collect(groupingBy(BlogPost::getType, () -> new EnumMap<>(BlogPostType.class), toList()));
 
-        assertEquals(2, postsPerType
-          .get(BlogPostType.NEWS)
-          .size());
-        assertEquals(1, postsPerType
-          .get(BlogPostType.GUIDE)
-          .size());
-        assertEquals(2, postsPerType
-          .get(BlogPostType.REVIEW)
-          .size());
+        assertEquals(2, postsPerType.get(BlogPostType.NEWS)
+            .size());
+        assertEquals(1, postsPerType.get(BlogPostType.GUIDE)
+            .size());
+        assertEquals(2, postsPerType.get(BlogPostType.REVIEW)
+            .size());
     }
 
     @Test
     public void givenAListOfPosts_whenGroupedByTypeInSets_thenGetAMapBetweenTypesAndSetsOfPosts() {
-        Map<BlogPostType, Set<BlogPost>> postsPerType = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getType, toSet()));
+        Map<BlogPostType, Set<BlogPost>> postsPerType = posts.stream()
+            .collect(groupingBy(BlogPost::getType, toSet()));
 
-        assertEquals(2, postsPerType
-          .get(BlogPostType.NEWS)
-          .size());
-        assertEquals(1, postsPerType
-          .get(BlogPostType.GUIDE)
-          .size());
-        assertEquals(2, postsPerType
-          .get(BlogPostType.REVIEW)
-          .size());
+        assertEquals(2, postsPerType.get(BlogPostType.NEWS)
+            .size());
+        assertEquals(1, postsPerType.get(BlogPostType.GUIDE)
+            .size());
+        assertEquals(2, postsPerType.get(BlogPostType.REVIEW)
+            .size());
     }
 
     @Test
     public void givenAListOfPosts_whenGroupedByTypeConcurrently_thenGetAMapBetweenTypeAndPosts() {
-        ConcurrentMap<BlogPostType, List<BlogPost>> postsPerType = posts
-          .parallelStream()
-          .collect(groupingByConcurrent(BlogPost::getType));
+        ConcurrentMap<BlogPostType, List<BlogPost>> postsPerType = posts.parallelStream()
+            .collect(groupingByConcurrent(BlogPost::getType));
 
-        assertEquals(2, postsPerType
-          .get(BlogPostType.NEWS)
-          .size());
-        assertEquals(1, postsPerType
-          .get(BlogPostType.GUIDE)
-          .size());
-        assertEquals(2, postsPerType
-          .get(BlogPostType.REVIEW)
-          .size());
+        assertEquals(2, postsPerType.get(BlogPostType.NEWS)
+            .size());
+        assertEquals(1, postsPerType.get(BlogPostType.GUIDE)
+            .size());
+        assertEquals(2, postsPerType.get(BlogPostType.REVIEW)
+            .size());
     }
 
     @Test
     public void givenAListOfPosts_whenGroupedByTypeAndAveragingLikes_thenGetAMapBetweenTypeAndAverageNumberOfLikes() {
-        Map<BlogPostType, Double> averageLikesPerType = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getType, averagingInt(BlogPost::getLikes)));
+        Map<BlogPostType, Double> averageLikesPerType = posts.stream()
+            .collect(groupingBy(BlogPost::getType, averagingInt(BlogPost::getLikes)));
 
-        assertEquals(25, averageLikesPerType
-          .get(BlogPostType.NEWS)
-          .intValue());
-        assertEquals(20, averageLikesPerType
-          .get(BlogPostType.GUIDE)
-          .intValue());
-        assertEquals(10, averageLikesPerType
-          .get(BlogPostType.REVIEW)
-          .intValue());
+        assertEquals(25, averageLikesPerType.get(BlogPostType.NEWS)
+            .intValue());
+        assertEquals(20, averageLikesPerType.get(BlogPostType.GUIDE)
+            .intValue());
+        assertEquals(10, averageLikesPerType.get(BlogPostType.REVIEW)
+            .intValue());
     }
 
     @Test
     public void givenAListOfPosts_whenGroupedByTypeAndCounted_thenGetAMapBetweenTypeAndNumberOfPosts() {
-        Map<BlogPostType, Long> numberOfPostsPerType = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getType, counting()));
+        Map<BlogPostType, Long> numberOfPostsPerType = posts.stream()
+            .collect(groupingBy(BlogPost::getType, counting()));
 
-        assertEquals(2, numberOfPostsPerType
-          .get(BlogPostType.NEWS)
-          .intValue());
-        assertEquals(1, numberOfPostsPerType
-          .get(BlogPostType.GUIDE)
-          .intValue());
-        assertEquals(2, numberOfPostsPerType
-          .get(BlogPostType.REVIEW)
-          .intValue());
+        assertEquals(2, numberOfPostsPerType.get(BlogPostType.NEWS)
+            .intValue());
+        assertEquals(1, numberOfPostsPerType.get(BlogPostType.GUIDE)
+            .intValue());
+        assertEquals(2, numberOfPostsPerType.get(BlogPostType.REVIEW)
+            .intValue());
     }
 
     @Test
     public void givenAListOfPosts_whenGroupedByTypeAndMaxingLikes_thenGetAMapBetweenTypeAndMaximumNumberOfLikes() {
-        Map<BlogPostType, Optional<BlogPost>> maxLikesPerPostType = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getType, maxBy(comparingInt(BlogPost::getLikes))));
+        Map<BlogPostType, Optional<BlogPost>> maxLikesPerPostType = posts.stream()
+            .collect(groupingBy(BlogPost::getType, maxBy(comparingInt(BlogPost::getLikes))));
 
-        assertTrue(maxLikesPerPostType
-          .get(BlogPostType.NEWS)
-          .isPresent());
-        assertEquals(35, maxLikesPerPostType
-          .get(BlogPostType.NEWS)
-          .get()
-          .getLikes());
+        assertTrue(maxLikesPerPostType.get(BlogPostType.NEWS)
+            .isPresent());
+        assertEquals(35, maxLikesPerPostType.get(BlogPostType.NEWS)
+            .get()
+            .getLikes());
 
-        assertTrue(maxLikesPerPostType
-          .get(BlogPostType.GUIDE)
-          .isPresent());
-        assertEquals(20, maxLikesPerPostType
-          .get(BlogPostType.GUIDE)
-          .get()
-          .getLikes());
+        assertTrue(maxLikesPerPostType.get(BlogPostType.GUIDE)
+            .isPresent());
+        assertEquals(20, maxLikesPerPostType.get(BlogPostType.GUIDE)
+            .get()
+            .getLikes());
 
-        assertTrue(maxLikesPerPostType
-          .get(BlogPostType.REVIEW)
-          .isPresent());
-        assertEquals(15, maxLikesPerPostType
-          .get(BlogPostType.REVIEW)
-          .get()
-          .getLikes());
+        assertTrue(maxLikesPerPostType.get(BlogPostType.REVIEW)
+            .isPresent());
+        assertEquals(15, maxLikesPerPostType.get(BlogPostType.REVIEW)
+            .get()
+            .getLikes());
     }
 
     @Test
     public void givenAListOfPosts_whenGroupedByAuthorAndThenByType_thenGetAMapBetweenAuthorAndMapsBetweenTypeAndBlogPosts() {
-        Map<String, Map<BlogPostType, List<BlogPost>>> map = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getAuthor, groupingBy(BlogPost::getType)));
+        Map<String, Map<BlogPostType, List<BlogPost>>> map = posts.stream()
+            .collect(groupingBy(BlogPost::getAuthor, groupingBy(BlogPost::getType)));
 
-        assertEquals(1, map
-          .get("Author 1")
-          .get(BlogPostType.NEWS)
-          .size());
-        assertEquals(1, map
-          .get("Author 1")
-          .get(BlogPostType.GUIDE)
-          .size());
-        assertEquals(1, map
-          .get("Author 1")
-          .get(BlogPostType.REVIEW)
-          .size());
+        assertEquals(1, map.get("Author 1")
+            .get(BlogPostType.NEWS)
+            .size());
+        assertEquals(1, map.get("Author 1")
+            .get(BlogPostType.GUIDE)
+            .size());
+        assertEquals(1, map.get("Author 1")
+            .get(BlogPostType.REVIEW)
+            .size());
 
-        assertEquals(1, map
-          .get("Author 2")
-          .get(BlogPostType.NEWS)
-          .size());
-        assertEquals(1, map
-          .get("Author 2")
-          .get(BlogPostType.REVIEW)
-          .size());
-        assertNull(map
-          .get("Author 2")
-          .get(BlogPostType.GUIDE));
+        assertEquals(1, map.get("Author 2")
+            .get(BlogPostType.NEWS)
+            .size());
+        assertEquals(1, map.get("Author 2")
+            .get(BlogPostType.REVIEW)
+            .size());
+        assertNull(map.get("Author 2")
+            .get(BlogPostType.GUIDE));
     }
 
     @Test
     public void givenAListOfPosts_whenGroupedByTypeAndSummarizingLikes_thenGetAMapBetweenTypeAndSummary() {
-        Map<BlogPostType, IntSummaryStatistics> likeStatisticsPerType = posts
-          .stream()
-          .collect(groupingBy(BlogPost::getType, summarizingInt(BlogPost::getLikes)));
+        Map<BlogPostType, IntSummaryStatistics> likeStatisticsPerType = posts.stream()
+            .collect(groupingBy(BlogPost::getType, summarizingInt(BlogPost::getLikes)));
 
         IntSummaryStatistics newsLikeStatistics = likeStatisticsPerType.get(BlogPostType.NEWS);
 

core-java/src/test/java/com/baeldung/java8/Java8MapAndFlatMap.java

@@ -17,8 +17,8 @@ public class Java8MapAndFlatMap {
     @Test
     public void givenStream_whenCalledMap_thenProduceList() {
         List<String> myList = Stream.of("a", "b")
-                .map(String::toUpperCase)
-                .collect(Collectors.toList());
+            .map(String::toUpperCase)
+            .collect(Collectors.toList());
         assertEquals(asList("A", "B"), myList);
     }
 
@@ -27,9 +27,9 @@ public class Java8MapAndFlatMap {
         List<List<String>> list = Arrays.asList(Arrays.asList("a"), Arrays.asList("b"));
         System.out.println(list);
 
-        System.out.println(list
-                .stream().flatMap(Collection::stream)
-                .collect(Collectors.toList()));
+        System.out.println(list.stream()
+            .flatMap(Collection::stream)
+            .collect(Collectors.toList()));
     }
 
     @Test
@@ -40,13 +40,11 @@ public class Java8MapAndFlatMap {
 
     @Test
     public void givenOptional_whenCalledFlatMap_thenProduceFlattenedOptional() {
-        assertEquals(Optional.of(Optional.of("STRING")), Optional
-                .of("string")
-                .map(s -> Optional.of("STRING")));
+        assertEquals(Optional.of(Optional.of("STRING")), Optional.of("string")
+            .map(s -> Optional.of("STRING")));
 
-        assertEquals(Optional.of("STRING"), Optional
-                .of("string")
-                .flatMap(s -> Optional.of("STRING")));
+        assertEquals(Optional.of("STRING"), Optional.of("string")
+            .flatMap(s -> Optional.of("STRING")));
     }
 
 }

core-java/src/test/java/com/baeldung/java8/JavaFolderSizeUnitTest.java

@@ -55,7 +55,12 @@ public class JavaFolderSizeUnitTest {
     @Test
     public void whenGetFolderSizeUsingJava8_thenCorrect() throws IOException {
         final Path folder = Paths.get(path);
-        final long size = Files.walk(folder).filter(p -> p.toFile().isFile()).mapToLong(p -> p.toFile().length()).sum();
+        final long size = Files.walk(folder)
+            .filter(p -> p.toFile()
+                .isFile())
+            .mapToLong(p -> p.toFile()
+                .length())
+            .sum();
 
         assertEquals(EXPECTED_SIZE, size);
     }
@@ -72,8 +77,12 @@ public class JavaFolderSizeUnitTest {
     public void whenGetFolderSizeUsingGuava_thenCorrect() {
         final File folder = new File(path);
 
-        final Iterable<File> files = com.google.common.io.Files.fileTreeTraverser().breadthFirstTraversal(folder);
-        final long size = StreamSupport.stream(files.spliterator(), false).filter(File::isFile).mapToLong(File::length).sum();
+        final Iterable<File> files = com.google.common.io.Files.fileTreeTraverser()
+            .breadthFirstTraversal(folder);
+        final long size = StreamSupport.stream(files.spliterator(), false)
+            .filter(File::isFile)
+            .mapToLong(File::length)
+            .sum();
 
         assertEquals(EXPECTED_SIZE, size);
     }

core-java/src/test/java/com/baeldung/java8/comparator/Java8ComparatorUnitTest.java

@@ -1,4 +1,5 @@
 package com.baeldung.java8.comparator;
+
 import java.util.Arrays;
 import java.util.Comparator;
 
@@ -25,44 +26,32 @@ public class Java8ComparatorUnitTest {
 
     @Before
     public void initData() {
-        employees = new Employee[] { new Employee("John", 25, 3000, 9922001), new Employee("Ace", 22, 2000, 5924001),
-             new Employee("Keith", 35, 4000, 3924401) };
-        employeesArrayWithNulls = new Employee[] { new Employee("John", 25, 3000, 9922001), null, new Employee("Ace", 22, 2000, 5924001),
-             null, new Employee("Keith", 35, 4000, 3924401) };
+        employees = new Employee[] { new Employee("John", 25, 3000, 9922001), new Employee("Ace", 22, 2000, 5924001), new Employee("Keith", 35, 4000, 3924401) };
+        employeesArrayWithNulls = new Employee[] { new Employee("John", 25, 3000, 9922001), null, new Employee("Ace", 22, 2000, 5924001), null, new Employee("Keith", 35, 4000, 3924401) };
 
-        sortedEmployeesByName = new Employee[] { new Employee("Ace", 22, 2000, 5924001), 
-            new Employee("John", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
-        sortedEmployeesByNameDesc = new Employee[] { new Employee("Keith", 35, 4000, 3924401), new Employee("John", 25, 3000, 9922001),
-             new Employee("Ace", 22, 2000, 5924001) };
+        sortedEmployeesByName = new Employee[] { new Employee("Ace", 22, 2000, 5924001), new Employee("John", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
+        sortedEmployeesByNameDesc = new Employee[] { new Employee("Keith", 35, 4000, 3924401), new Employee("John", 25, 3000, 9922001), new Employee("Ace", 22, 2000, 5924001) };
 
-        sortedEmployeesByAge = new Employee[] {  new Employee("Ace", 22, 2000, 5924001),
-            new Employee("John", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
+        sortedEmployeesByAge = new Employee[] { new Employee("Ace", 22, 2000, 5924001), new Employee("John", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
 
-        sortedEmployeesByMobile = new Employee[] { new Employee("Keith", 35, 4000, 3924401), new Employee("Ace", 22, 2000, 5924001),
-             new Employee("John", 25, 3000, 9922001), };
+        sortedEmployeesByMobile = new Employee[] { new Employee("Keith", 35, 4000, 3924401), new Employee("Ace", 22, 2000, 5924001), new Employee("John", 25, 3000, 9922001), };
 
-        sortedEmployeesBySalary = new Employee[] { new Employee("Ace", 22, 2000, 5924001), new Employee("John", 25, 3000, 9922001),
-            new Employee("Keith", 35, 4000, 3924401),  };
+        sortedEmployeesBySalary = new Employee[] { new Employee("Ace", 22, 2000, 5924001), new Employee("John", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401), };
 
-        sortedEmployeesArray_WithNullsFirst = new Employee[] { null, null, new Employee("Ace", 22, 2000, 5924001),
-             new Employee("John", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
-        sortedEmployeesArray_WithNullsLast = new Employee[] { new Employee("Ace", 22, 2000, 5924001), 
-            new Employee("John", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401), null, null };
+        sortedEmployeesArray_WithNullsFirst = new Employee[] { null, null, new Employee("Ace", 22, 2000, 5924001), new Employee("John", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
+        sortedEmployeesArray_WithNullsLast = new Employee[] { new Employee("Ace", 22, 2000, 5924001), new Employee("John", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401), null, null };
 
-        someMoreEmployees = new Employee[] { new Employee("Jake", 25, 3000, 9922001), new Employee("Jake", 22, 2000, 5924001),
-            new Employee("Ace", 22, 3000, 6423001),  new Employee("Keith", 35, 4000, 3924401) };
+        someMoreEmployees = new Employee[] { new Employee("Jake", 25, 3000, 9922001), new Employee("Jake", 22, 2000, 5924001), new Employee("Ace", 22, 3000, 6423001), new Employee("Keith", 35, 4000, 3924401) };
 
-        sortedEmployeesByAgeName = new Employee[] {  new Employee("Ace", 22, 3000, 6423001),
-            new Employee("Jake", 22, 2000, 5924001), new Employee("Jake", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
-        sortedEmployeesByNameAge = new Employee[] { new Employee("Ace", 22, 3000, 6423001), 
-            new Employee("Jake", 22, 2000, 5924001), new Employee("Jake", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
+        sortedEmployeesByAgeName = new Employee[] { new Employee("Ace", 22, 3000, 6423001), new Employee("Jake", 22, 2000, 5924001), new Employee("Jake", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
+        sortedEmployeesByNameAge = new Employee[] { new Employee("Ace", 22, 3000, 6423001), new Employee("Jake", 22, 2000, 5924001), new Employee("Jake", 25, 3000, 9922001), new Employee("Keith", 35, 4000, 3924401) };
     }
 
     @Test
     public void whenComparing_thenSortedByName() {
         Comparator<Employee> employeeNameComparator = Comparator.comparing(Employee::getName);
         Arrays.sort(employees, employeeNameComparator);
-//         System.out.println(Arrays.toString(employees));
+        // System.out.println(Arrays.toString(employees));
         assertTrue(Arrays.equals(employees, sortedEmployeesByName));
     }
 
@@ -72,16 +61,16 @@ public class Java8ComparatorUnitTest {
             return s2.compareTo(s1);
         });
         Arrays.sort(employees, employeeNameComparator);
-//         System.out.println(Arrays.toString(employees));
+        // System.out.println(Arrays.toString(employees));
         assertTrue(Arrays.equals(employees, sortedEmployeesByNameDesc));
     }
-    
+
     @Test
     public void whenReversed_thenSortedByNameDesc() {
-    	Comparator<Employee> employeeNameComparator = Comparator.comparing(Employee::getName);
-    	Comparator<Employee> employeeNameComparatorReversed = employeeNameComparator.reversed();
+        Comparator<Employee> employeeNameComparator = Comparator.comparing(Employee::getName);
+        Comparator<Employee> employeeNameComparatorReversed = employeeNameComparator.reversed();
         Arrays.sort(employees, employeeNameComparatorReversed);
-//         System.out.println(Arrays.toString(employees));
+        // System.out.println(Arrays.toString(employees));
         assertTrue(Arrays.equals(employees, sortedEmployeesByNameDesc));
     }
 
@@ -89,7 +78,7 @@ public class Java8ComparatorUnitTest {
     public void whenComparingInt_thenSortedByAge() {
         Comparator<Employee> employeeAgeComparator = Comparator.comparingInt(Employee::getAge);
         Arrays.sort(employees, employeeAgeComparator);
-//         System.out.println(Arrays.toString(employees));
+        // System.out.println(Arrays.toString(employees));
         assertTrue(Arrays.equals(employees, sortedEmployeesByAge));
     }
 
@@ -97,7 +86,7 @@ public class Java8ComparatorUnitTest {
     public void whenComparingLong_thenSortedByMobile() {
         Comparator<Employee> employeeMobileComparator = Comparator.comparingLong(Employee::getMobile);
         Arrays.sort(employees, employeeMobileComparator);
-//         System.out.println(Arrays.toString(employees));
+        // System.out.println(Arrays.toString(employees));
         assertTrue(Arrays.equals(employees, sortedEmployeesByMobile));
     }
 
@@ -105,7 +94,7 @@ public class Java8ComparatorUnitTest {
     public void whenComparingDouble_thenSortedBySalary() {
         Comparator<Employee> employeeSalaryComparator = Comparator.comparingDouble(Employee::getSalary);
         Arrays.sort(employees, employeeSalaryComparator);
-//         System.out.println(Arrays.toString(employees));
+        // System.out.println(Arrays.toString(employees));
         assertTrue(Arrays.equals(employees, sortedEmployeesBySalary));
     }
 
@@ -113,7 +102,7 @@ public class Java8ComparatorUnitTest {
     public void whenNaturalOrder_thenSortedByName() {
         Comparator<Employee> employeeNameComparator = Comparator.<Employee> naturalOrder();
         Arrays.sort(employees, employeeNameComparator);
-//         System.out.println(Arrays.toString(employees));
+        // System.out.println(Arrays.toString(employees));
         assertTrue(Arrays.equals(employees, sortedEmployeesByName));
     }
 
@@ -121,7 +110,7 @@ public class Java8ComparatorUnitTest {
     public void whenReverseOrder_thenSortedByNameDesc() {
         Comparator<Employee> employeeNameComparator = Comparator.<Employee> reverseOrder();
         Arrays.sort(employees, employeeNameComparator);
-//        System.out.println(Arrays.toString(employees));
+        // System.out.println(Arrays.toString(employees));
         assertTrue(Arrays.equals(employees, sortedEmployeesByNameDesc));
     }
 
@@ -130,7 +119,7 @@ public class Java8ComparatorUnitTest {
         Comparator<Employee> employeeNameComparator = Comparator.comparing(Employee::getName);
         Comparator<Employee> employeeNameComparator_nullFirst = Comparator.nullsFirst(employeeNameComparator);
         Arrays.sort(employeesArrayWithNulls, employeeNameComparator_nullFirst);
-//         System.out.println(Arrays.toString(employeesArrayWithNulls));
+        // System.out.println(Arrays.toString(employeesArrayWithNulls));
         assertTrue(Arrays.equals(employeesArrayWithNulls, sortedEmployeesArray_WithNullsFirst));
     }
 
@@ -139,27 +128,28 @@ public class Java8ComparatorUnitTest {
         Comparator<Employee> employeeNameComparator = Comparator.comparing(Employee::getName);
         Comparator<Employee> employeeNameComparator_nullLast = Comparator.nullsLast(employeeNameComparator);
         Arrays.sort(employeesArrayWithNulls, employeeNameComparator_nullLast);
-//         System.out.println(Arrays.toString(employeesArrayWithNulls));
+        // System.out.println(Arrays.toString(employeesArrayWithNulls));
         assertTrue(Arrays.equals(employeesArrayWithNulls, sortedEmployeesArray_WithNullsLast));
     }
 
     @Test
     public void whenThenComparing_thenSortedByAgeName() {
-        Comparator<Employee> employee_Age_Name_Comparator = Comparator.comparing(Employee::getAge).thenComparing(Employee::getName);
+        Comparator<Employee> employee_Age_Name_Comparator = Comparator.comparing(Employee::getAge)
+            .thenComparing(Employee::getName);
 
         Arrays.sort(someMoreEmployees, employee_Age_Name_Comparator);
-//         System.out.println(Arrays.toString(someMoreEmployees));
+        // System.out.println(Arrays.toString(someMoreEmployees));
         assertTrue(Arrays.equals(someMoreEmployees, sortedEmployeesByAgeName));
     }
 
     @Test
     public void whenThenComparing_thenSortedByNameAge() {
-        Comparator<Employee> employee_Name_Age_Comparator = Comparator.comparing(Employee::getName).thenComparingInt(Employee::getAge);
+        Comparator<Employee> employee_Name_Age_Comparator = Comparator.comparing(Employee::getName)
+            .thenComparingInt(Employee::getAge);
 
         Arrays.sort(someMoreEmployees, employee_Name_Age_Comparator);
-//        System.out.println(Arrays.toString(someMoreEmployees));
+        // System.out.println(Arrays.toString(someMoreEmployees));
         assertTrue(Arrays.equals(someMoreEmployees, sortedEmployeesByNameAge));
     }
 
-
 }

core-java/src/test/java/com/baeldung/java8/optional/OptionalUnitTest.java

@@ -17,7 +17,6 @@ public class OptionalUnitTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(OptionalUnitTest.class);
 
-    
     // creating Optional
     @Test
     public void whenCreatesEmptyOptional_thenCorrect() {
@@ -94,9 +93,11 @@ public class OptionalUnitTest {
     public void whenOptionalFilterWorks_thenCorrect() {
         Integer year = 2016;
         Optional<Integer> yearOptional = Optional.of(year);
-        boolean is2016 = yearOptional.filter(y -> y == 2016).isPresent();
+        boolean is2016 = yearOptional.filter(y -> y == 2016)
+            .isPresent();
         assertTrue(is2016);
-        boolean is2017 = yearOptional.filter(y -> y == 2017).isPresent();
+        boolean is2017 = yearOptional.filter(y -> y == 2017)
+            .isPresent();
         assertFalse(is2017);
     }
 
@@ -128,7 +129,11 @@ public class OptionalUnitTest {
     }
 
     public boolean priceIsInRange2(Modem modem2) {
-        return Optional.ofNullable(modem2).map(Modem::getPrice).filter(p -> p >= 10).filter(p -> p <= 15).isPresent();
+        return Optional.ofNullable(modem2)
+            .map(Modem::getPrice)
+            .filter(p -> p >= 10)
+            .filter(p -> p <= 15)
+            .isPresent();
     }
 
     // Transforming Value With map()
@@ -137,7 +142,8 @@ public class OptionalUnitTest {
         List<String> companyNames = Arrays.asList("paypal", "oracle", "", "microsoft", "", "apple");
         Optional<List<String>> listOptional = Optional.of(companyNames);
 
-        int size = listOptional.map(List::size).orElse(0);
+        int size = listOptional.map(List::size)
+            .orElse(0);
         assertEquals(6, size);
     }
 
@@ -146,7 +152,8 @@ public class OptionalUnitTest {
         String name = "baeldung";
         Optional<String> nameOptional = Optional.of(name);
 
-        int len = nameOptional.map(String::length).orElse(0);
+        int len = nameOptional.map(String::length)
+            .orElse(0);
         assertEquals(8, len);
     }
 
@@ -154,10 +161,13 @@ public class OptionalUnitTest {
     public void givenOptional_whenMapWorksWithFilter_thenCorrect() {
         String password = " password ";
         Optional<String> passOpt = Optional.of(password);
-        boolean correctPassword = passOpt.filter(pass -> pass.equals("password")).isPresent();
+        boolean correctPassword = passOpt.filter(pass -> pass.equals("password"))
+            .isPresent();
         assertFalse(correctPassword);
 
-        correctPassword = passOpt.map(String::trim).filter(pass -> pass.equals("password")).isPresent();
+        correctPassword = passOpt.map(String::trim)
+            .filter(pass -> pass.equals("password"))
+            .isPresent();
         assertTrue(correctPassword);
     }
 
@@ -172,7 +182,8 @@ public class OptionalUnitTest {
         String name1 = nameOptional.orElseThrow(IllegalArgumentException::new);
         assertEquals("john", name1);
 
-        String name = personOptional.flatMap(Person::getName).orElseThrow(IllegalArgumentException::new);
+        String name = personOptional.flatMap(Person::getName)
+            .orElseThrow(IllegalArgumentException::new);
         assertEquals("john", name);
     }
 
@@ -182,7 +193,9 @@ public class OptionalUnitTest {
         person.setPassword("password");
         Optional<Person> personOptional = Optional.of(person);
 
-        String password = personOptional.flatMap(Person::getPassword).filter(cleanPass -> cleanPass.equals("password")).orElseThrow(IllegalArgumentException::new);
+        String password = personOptional.flatMap(Person::getPassword)
+            .filter(cleanPass -> cleanPass.equals("password"))
+            .orElseThrow(IllegalArgumentException::new);
         assertEquals("password", password);
     }
 
@@ -190,7 +203,8 @@ public class OptionalUnitTest {
     @Test
     public void whenOrElseWorks_thenCorrect() {
         String nullName = null;
-        String name = Optional.ofNullable(nullName).orElse("john");
+        String name = Optional.ofNullable(nullName)
+            .orElse("john");
         assertEquals("john", name);
     }
 
@@ -198,7 +212,8 @@ public class OptionalUnitTest {
     @Test
     public void whenOrElseGetWorks_thenCorrect() {
         String nullName = null;
-        String name = Optional.ofNullable(nullName).orElseGet(() -> "john");
+        String name = Optional.ofNullable(nullName)
+            .orElseGet(() -> "john");
         assertEquals("john", name);
 
     }
@@ -207,11 +222,13 @@ public class OptionalUnitTest {
     public void whenOrElseGetAndOrElseOverlap_thenCorrect() {
         String text = null;
         LOG.debug("Using orElseGet:");
-        String defaultText = Optional.ofNullable(text).orElseGet(this::getMyDefault);
+        String defaultText = Optional.ofNullable(text)
+            .orElseGet(this::getMyDefault);
         assertEquals("Default Value", defaultText);
 
         LOG.debug("Using orElse:");
-        defaultText = Optional.ofNullable(text).orElse(getMyDefault());
+        defaultText = Optional.ofNullable(text)
+            .orElse(getMyDefault());
         assertEquals("Default Value", defaultText);
     }
 
@@ -219,11 +236,13 @@ public class OptionalUnitTest {
     public void whenOrElseGetAndOrElseDiffer_thenCorrect() {
         String text = "Text present";
         LOG.debug("Using orElseGet:");
-        String defaultText = Optional.ofNullable(text).orElseGet(this::getMyDefault);
+        String defaultText = Optional.ofNullable(text)
+            .orElseGet(this::getMyDefault);
         assertEquals("Text present", defaultText);
 
         LOG.debug("Using orElse:");
-        defaultText = Optional.ofNullable(text).orElse(getMyDefault());
+        defaultText = Optional.ofNullable(text)
+            .orElse(getMyDefault());
         assertEquals("Text present", defaultText);
     }
 
@@ -231,7 +250,8 @@ public class OptionalUnitTest {
     @Test(expected = IllegalArgumentException.class)
     public void whenOrElseThrowWorks_thenCorrect() {
         String nullName = null;
-        String name = Optional.ofNullable(nullName).orElseThrow(IllegalArgumentException::new);
+        String name = Optional.ofNullable(nullName)
+            .orElseThrow(IllegalArgumentException::new);
     }
 
     public String getMyDefault() {

core-java/src/test/java/com/baeldung/list/flattennestedlist/FlattenNestedListUnitTest.java

@@ -43,6 +43,8 @@ public class FlattenNestedListUnitTest {
     }
 
     private <T> List<T> flattenListOfListsStream(List<List<T>> list) {
-        return list.stream().flatMap(Collection::stream).collect(Collectors.toList());
+        return list.stream()
+            .flatMap(Collection::stream)
+            .collect(Collectors.toList());
     }
 }

core-java/src/test/java/com/baeldung/maths/RoundTest.java

@@ -15,56 +15,56 @@ public class RoundTest {
     private double expected = 2.03d;
 
     @Test
-    public void givenDecimalNumber_whenRoundToNDecimalPlaces_thenGetExpectedResult() {   
+    public void givenDecimalNumber_whenRoundToNDecimalPlaces_thenGetExpectedResult() {
         Assert.assertEquals(expected, Round.round(value, places), delta);
         Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
         Assert.assertEquals(expected, Round.roundAvoid(value, places), delta);
         Assert.assertEquals(expected, Precision.round(value, places), delta);
         Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
-        
+
         places = 3;
         expected = 2.035d;
-        
+
         Assert.assertEquals(expected, Round.round(value, places), delta);
         Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
         Assert.assertEquals(expected, Round.roundAvoid(value, places), delta);
         Assert.assertEquals(expected, Precision.round(value, places), delta);
         Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
-        
+
         value = 1000.0d;
         places = 17;
         expected = 1000.0d;
-        
+
         Assert.assertEquals(expected, Round.round(value, places), delta);
         Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
         Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 92.23372036854776 !
         Assert.assertEquals(expected, Precision.round(value, places), delta);
         Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
-        
+
         value = 256.025d;
         places = 2;
         expected = 256.03d;
-        
+
         Assert.assertEquals(expected, Round.round(value, places), delta);
         Assert.assertNotEquals(expected, Round.roundNotPrecise(value, places), delta); // Returns: 256.02 !
         Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 256.02 !
         Assert.assertEquals(expected, Precision.round(value, places), delta);
         Assert.assertNotEquals(expected, DoubleRounder.round(value, places), delta); // Returns: 256.02 !
-        
-        value = 260.775d; 
+
+        value = 260.775d;
         places = 2;
         expected = 260.78d;
-        
+
         Assert.assertEquals(expected, Round.round(value, places), delta);
         Assert.assertNotEquals(expected, Round.roundNotPrecise(value, places), delta); // Returns: 260.77 !
         Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 260.77 !
         Assert.assertEquals(expected, Precision.round(value, places), delta);
         Assert.assertNotEquals(expected, DoubleRounder.round(value, places), delta); // Returns: 260.77 !
-        
+
         value = 90080070060.1d;
         places = 9;
         expected = 90080070060.1d;
-        
+
         Assert.assertEquals(expected, Round.round(value, places), delta);
         Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
         Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 9.223372036854776E9 !

core-java/src/test/java/com/baeldung/socket/EchoIntegrationTest.java

@@ -14,7 +14,8 @@ public class EchoIntegrationTest {
 
     @BeforeClass
     public static void start() throws InterruptedException {
-        Executors.newSingleThreadExecutor().submit(() -> new EchoServer().start(PORT));
+        Executors.newSingleThreadExecutor()
+            .submit(() -> new EchoServer().start(PORT));
         Thread.sleep(500);
     }
 

core-java/src/test/java/com/baeldung/socket/GreetServerIntegrationTest.java

@@ -17,7 +17,8 @@ public class GreetServerIntegrationTest {
 
     @BeforeClass
     public static void start() throws InterruptedException {
-        Executors.newSingleThreadExecutor().submit(() -> new GreetServer().start(PORT));
+        Executors.newSingleThreadExecutor()
+            .submit(() -> new GreetServer().start(PORT));
         Thread.sleep(500);
     }
 

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

@@ -0,0 +1,47 @@
+package com.baeldung.string;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+
+public class CharSequenceVsStringUnitTest {
+
+    @Test
+    public void givenUsingString_whenInstantiatingString_thenWrong() {
+        CharSequence firstString = "bealdung";
+        String secondString = "baeldung";
+
+        assertNotEquals(firstString, secondString);
+    }
+
+    @Test
+    public void givenIdenticalCharSequences_whenCastToString_thenEqual() {
+        CharSequence charSequence1 = "baeldung_1";
+        CharSequence charSequence2 = "baeldung_2";
+
+        assertTrue(charSequence1.toString().compareTo(charSequence2.toString()) > 0);
+    }
+
+    @Test
+    public void givenString_whenAppended_thenUnmodified() {
+        String test = "a";
+        int firstAddressOfTest = System.identityHashCode(test);
+        test += "b";
+        int secondAddressOfTest = System.identityHashCode(test);
+
+        assertEquals(firstAddressOfTest, secondAddressOfTest);
+    }
+
+    @Test
+    public void givenStringBuilder_whenAppended_thenModified() {
+        StringBuilder test = new StringBuilder();
+        test.append("a");
+        int firstAddressOfTest = System.identityHashCode(test);
+        test.append("b");
+        int secondAddressOfTest = System.identityHashCode(test);
+
+        assertEquals(firstAddressOfTest, secondAddressOfTest);
+    }
+}

core-java/src/test/java/org/baeldung/java/JavaIoUnitTest.java

@@ -96,9 +96,12 @@ public class JavaIoUnitTest {
     // utils
 
     private final void logMemory() {
-        logger.info("Max Memory: {} Mb", Runtime.getRuntime().maxMemory() / 1048576);
-        logger.info("Total Memory: {} Mb", Runtime.getRuntime().totalMemory() / 1048576);
-        logger.info("Free Memory: {} Mb", Runtime.getRuntime().freeMemory() / 1048576);
+        logger.info("Max Memory: {} Mb", Runtime.getRuntime()
+            .maxMemory() / 1048576);
+        logger.info("Total Memory: {} Mb", Runtime.getRuntime()
+            .totalMemory() / 1048576);
+        logger.info("Free Memory: {} Mb", Runtime.getRuntime()
+            .freeMemory() / 1048576);
     }
 
 }

core-java/src/test/java/org/baeldung/java/JavaRandomUnitTest.java

@@ -13,7 +13,6 @@ public class JavaRandomUnitTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(JavaRandomUnitTest.class);
 
-
     // tests - random long
 
     @Test
@@ -25,7 +24,8 @@ public class JavaRandomUnitTest {
 
     @Test
     public void givenUsingApacheCommons_whenGeneratingRandomLongUnbounded_thenCorrect() {
-        final long generatedLong = new RandomDataGenerator().getRandomGenerator().nextLong();
+        final long generatedLong = new RandomDataGenerator().getRandomGenerator()
+            .nextLong();
 
         LOG.debug("{}", generatedLong);
     }
@@ -68,7 +68,8 @@ public class JavaRandomUnitTest {
 
     @Test
     public void givenUsingApache_whenGeneratingRandomIntegerUnbounded_thenCorrect() {
-        final Integer generatedInteger = new RandomDataGenerator().getRandomGenerator().nextInt();
+        final Integer generatedInteger = new RandomDataGenerator().getRandomGenerator()
+            .nextInt();
 
         LOG.debug("{}", generatedInteger);
     }
@@ -93,7 +94,8 @@ public class JavaRandomUnitTest {
 
     @Test
     public void givenUsingApache_whenGeneratingRandomFloatUnbounded_thenCorrect() {
-        final float generatedFloat = new RandomDataGenerator().getRandomGenerator().nextFloat();
+        final float generatedFloat = new RandomDataGenerator().getRandomGenerator()
+            .nextFloat();
 
         LOG.debug("{}", generatedFloat);
     }
@@ -111,7 +113,8 @@ public class JavaRandomUnitTest {
     public void givenUsingApache_whenGeneratingRandomFloatBounded_thenCorrect() {
         final float leftLimit = 1F;
         final float rightLimit = 10F;
-        final float randomFloat = new RandomDataGenerator().getRandomGenerator().nextFloat();
+        final float randomFloat = new RandomDataGenerator().getRandomGenerator()
+            .nextFloat();
         final float generatedFloat = leftLimit + randomFloat * (rightLimit - leftLimit);
 
         LOG.debug("{}", generatedFloat);
@@ -128,7 +131,8 @@ public class JavaRandomUnitTest {
 
     @Test
     public void givenUsingApache_whenGeneratingRandomDoubleUnbounded_thenCorrect() {
-        final double generatedDouble = new RandomDataGenerator().getRandomGenerator().nextDouble();
+        final double generatedDouble = new RandomDataGenerator().getRandomGenerator()
+            .nextDouble();
 
         LOG.debug("{}", generatedDouble);
     }

core-java/src/test/java/org/baeldung/java/JavaTimerLongRunningUnitTest.java

@@ -15,7 +15,6 @@ public class JavaTimerLongRunningUnitTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(JavaTimerLongRunningUnitTest.class);
 
-
     // tests
 
     @Test
@@ -23,7 +22,8 @@ public class JavaTimerLongRunningUnitTest {
         final TimerTask timerTask = new TimerTask() {
             @Override
             public void run() {
-                LOG.debug("Task performed on: " + new Date() + "\n" + "Thread's name: " + Thread.currentThread().getName());
+                LOG.debug("Task performed on: " + new Date() + "\n" + "Thread's name: " + Thread.currentThread()
+                    .getName());
             }
         };
         final Timer timer = new Timer("Timer");

core-java/src/test/java/org/baeldung/java/lists/ListToSTring.java

@@ -0,0 +1,31 @@
+package org.baeldung.java.lists;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.Test;
+
+public class ListToSTring {
+
+    @Test
+    public void whenListToString_thenPrintDefault() {
+        List<Integer> intLIst = Arrays.asList(1, 2, 3);
+        System.out.println(intLIst);
+    }
+
+    @Test
+    public void whenCollectorsJoining_thenPrintCustom() {
+        List<Integer> intList = Arrays.asList(1, 2, 3);
+        System.out.println(intList.stream()
+            .map(n -> String.valueOf(n))
+            .collect(Collectors.joining("-", "{", "}")));
+    }
+    
+    @Test
+    public void whenStringUtilsJoin_thenPrintCustom() {
+        List<Integer> intList = Arrays.asList(1, 2, 3);
+       System.out.println(StringUtils.join(intList, "|"));
+    }
+}

core-java/src/test/java/org/baeldung/java/sorting/Employee.java

@@ -38,7 +38,8 @@ public class Employee implements Comparable {
 
     @Override
     public boolean equals(Object obj) {
-        return ((Employee) obj).getName().equals(getName());
+        return ((Employee) obj).getName()
+            .equals(getName());
     }
 
     @Override
@@ -49,7 +50,13 @@ public class Employee implements Comparable {
 
     @Override
     public String toString() {
-        return new StringBuffer().append("(").append(getName()).append(getAge()).append(",").append(getSalary()).append(")").toString();
+        return new StringBuffer().append("(")
+            .append(getName())
+            .append(getAge())
+            .append(",")
+            .append(getSalary())
+            .append(")")
+            .toString();
     }
 
 }

core-java/src/test/java/org/baeldung/java/sorting/JavaSortingUnitTest.java

@@ -113,7 +113,8 @@ public class JavaSortingUnitTest {
             sortedMap.put(entry.getKey(), entry.getValue());
         }
 
-        assertTrue(Arrays.equals(sortedMap.keySet().toArray(), sortedKeys));
+        assertTrue(Arrays.equals(sortedMap.keySet()
+            .toArray(), sortedKeys));
     }
 
     @Test
@@ -127,7 +128,8 @@ public class JavaSortingUnitTest {
             sortedMap.put(entry.getKey(), entry.getValue());
         }
 
-        assertTrue(Arrays.equals(sortedMap.values().toArray(), sortedValues));
+        assertTrue(Arrays.equals(sortedMap.values()
+            .toArray(), sortedValues));
     }
 
     @Test

feign/src/main/java/com/baeldung/feign/BookControllerFeignClientBuilder.java

@@ -14,6 +14,12 @@ public class BookControllerFeignClientBuilder {
     private BookClient bookClient = createClient(BookClient.class, "http://localhost:8081/api/books");
 
     private static <T> T createClient(Class<T> type, String uri) {
-        return Feign.builder().client(new OkHttpClient()).encoder(new GsonEncoder()).decoder(new GsonDecoder()).logger(new Slf4jLogger(type)).logLevel(Logger.Level.FULL).target(type, uri);
+        return Feign.builder()
+            .client(new OkHttpClient())
+            .encoder(new GsonEncoder())
+            .decoder(new GsonDecoder())
+            .logger(new Slf4jLogger(type))
+            .logLevel(Logger.Level.FULL)
+            .target(type, uri);
     }
 }

feign/src/test/java/com/baeldung/feign/clients/BookClientLiveTest.java

@@ -34,25 +34,31 @@ public class BookClientLiveTest {
 
     @Test
     public void givenBookClient_shouldRunSuccessfully() throws Exception {
-        List<Book> books = bookClient.findAll().stream().map(BookResource::getBook).collect(Collectors.toList());
+        List<Book> books = bookClient.findAll()
+            .stream()
+            .map(BookResource::getBook)
+            .collect(Collectors.toList());
         assertTrue(books.size() > 2);
         log.info("{}", books);
     }
 
     @Test
     public void givenBookClient_shouldFindOneBook() throws Exception {
-        Book book = bookClient.findByIsbn("0151072558").getBook();
+        Book book = bookClient.findByIsbn("0151072558")
+            .getBook();
         assertThat(book.getAuthor(), containsString("Orwell"));
         log.info("{}", book);
     }
 
     @Test
     public void givenBookClient_shouldPostBook() throws Exception {
-        String isbn = UUID.randomUUID().toString();
+        String isbn = UUID.randomUUID()
+            .toString();
         Book book = new Book(isbn, "Me", "It's me!", null, null);
         bookClient.create(book);
 
-        book = bookClient.findByIsbn(isbn).getBook();
+        book = bookClient.findByIsbn(isbn)
+            .getBook();
         assertThat(book.getAuthor(), is("Me"));
         log.info("{}", book);
     }

guest/logback-example/pom.xml

@@ -0,0 +1,41 @@
+<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.stackify</groupId>
+	<artifactId>logback-example</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+
+	<dependencies>
+		<dependency>
+			<groupId>ch.qos.logback</groupId>
+			<artifactId>logback-classic</artifactId>
+			<version>1.2.3</version>
+		</dependency>
+
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>4.12</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.codehaus.janino</groupId>
+			<artifactId>janino</artifactId>
+			<version>3.0.7</version>
+		</dependency>
+
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.5</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+</project>

guest/logback-example/src/main/java/com/stackify/logging/IgnoreLoggerFilter.java

@@ -0,0 +1,28 @@
+package com.stackify.logging;
+
+import org.slf4j.Marker;
+
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.turbo.TurboFilter;
+import ch.qos.logback.core.spi.FilterReply;
+
+public class IgnoreLoggerFilter extends TurboFilter {
+
+    private String loggerName;
+
+    @Override
+    public FilterReply decide(Marker marker, Logger logger, Level level, String format, Object[] params, Throwable t) {
+        if (loggerName == null) {
+            return FilterReply.NEUTRAL;
+        } else if (loggerName.equals(logger.getName())) {
+            return FilterReply.DENY;
+        } else
+            return FilterReply.NEUTRAL;
+    }
+
+    public void setLoggerName(String loggerName) {
+        this.loggerName = loggerName;
+    }
+
+}

guest/logback-example/src/main/java/com/stackify/models/Employee.java

@@ -0,0 +1,43 @@
+package com.stackify.models;
+
+public class Employee {
+
+    private String email;
+    private String name;
+
+    private double salary;
+
+    public Employee() {
+    }
+
+    public Employee(String email, String name, double salary) {
+        this.email = email;
+        this.name = name;
+        this.salary = salary;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public void setSalary(double salary) {
+        this.salary = salary;
+    }
+
+}

guest/logback-example/src/main/java/com/stackify/services/EmployeeService.java

@@ -0,0 +1,11 @@
+package com.stackify.services;
+
+import com.stackify.models.Employee;
+
+public class EmployeeService {
+
+    public double calculateBonus(Employee user) {
+        return 0.1 * user.getSalary();
+    }
+
+}

guest/logback-example/src/main/resources/application.properties

@@ -0,0 +1 @@
+env=dev

guest/logback-example/src/main/resources/logback.xml

@@ -0,0 +1,151 @@
+<configuration debug="true">
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n</pattern>
+        </encoder>
+        <target>System.out</target>
+    </appender>
+
+    <property name="fileName" value="file.log" />
+    <property scope="context" resource="application.properties" />
+
+    <!-- configure appenders -->
+    <appender name="rollingFileAppender" class="ch.qos.logback.core.rolling.RollingFileAppender">
+        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
+            <fileNamePattern>log-%d{yyyy-MM-dd}.log</fileNamePattern>
+            <maxHistory>30</maxHistory>
+            <totalSizeCap>3GB</totalSizeCap>
+        </rollingPolicy>
+        <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
+            <maxFileSize>3MB</maxFileSize>
+        </triggeringPolicy>
+        <encoder>
+            <pattern>%d [%thread] %-5level %logger{50} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="roleSiftingAppender" class="ch.qos.logback.classic.sift.SiftingAppender">
+        <discriminator>
+            <key>userRole</key>
+            <defaultValue>ANONYMOUS</defaultValue>
+        </discriminator>
+        <sift>
+            <appender name="fileAppender" class="ch.qos.logback.core.FileAppender">
+                <file>${userRole}.log</file>
+                <layout class="ch.qos.logback.classic.PatternLayout">
+                    <pattern>%d [%thread] %level %mdc %logger{50} - %msg%n</pattern>
+                </layout>
+            </appender>
+        </sift>
+    </appender>
+
+    <!-- configure layouts -->
+    <appender name="colorAppender" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
+            <pattern>%d %green([%thread]) %highlight(%level) %logger{50} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="htmlAppender" class="ch.qos.logback.core.FileAppender">
+        <encoder class="ch.qos.logback.core.encoder.LayoutWrappingEncoder">
+            <layout class="ch.qos.logback.classic.html.HTMLLayout">
+                <pattern>%thread%level%logger%msg</pattern>
+            </layout>
+        </encoder>
+        <file>log.html</file>
+    </appender>
+
+    <!-- configure filters -->
+    <appender name="STDOUT_LEVEL_FILTER_APPENDER" class="ch.qos.logback.core.ConsoleAppender">
+        <filter class="ch.qos.logback.classic.filter.LevelFilter">
+            <level>ERROR</level>
+            <onMatch>ACCEPT</onMatch>
+            <onMismatch>DENY</onMismatch>
+        </filter>
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n</pattern>
+        </encoder>
+        <target>System.err</target>
+    </appender>
+
+    <appender name="STDOUT_THRESHOLD_FILTER_APPENDER" class="ch.qos.logback.core.ConsoleAppender">
+        <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
+            <level>WARN</level>
+        </filter>
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="STDOUT_EVALUATOR_FILTER_APPENDER" class="ch.qos.logback.core.ConsoleAppender">
+        <filter class="ch.qos.logback.core.filter.EvaluatorFilter">
+            <evaluator class="ch.qos.logback.classic.boolex.JaninoEventEvaluator">
+                <expression>return (level > DEBUG &amp;&amp; message.toLowerCase().contains("employee"));</expression>
+            </evaluator>
+            <OnMismatch>DENY</OnMismatch>
+            <OnMatch>NEUTRAL</OnMatch>
+        </filter>
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <!-- configure turbo filters -->
+    <turboFilter class="ch.qos.logback.classic.turbo.DuplicateMessageFilter">
+        <AllowedRepetitions>2</AllowedRepetitions>
+    </turboFilter>
+
+    <turboFilter class="com.stackify.logging.IgnoreLoggerFilter">
+        <LoggerName>ignoredColorLogger</LoggerName>
+    </turboFilter>
+
+    <!-- configure loggers -->
+    <logger level="info" name="rollingFileLogger" additivity="false">
+        <appender-ref ref="rollingFileAppender" />
+    </logger>
+    
+    <logger level="info" name="htmlLogger" additivity="false">
+        <appender-ref ref="htmlAppender" />
+    </logger>
+    
+    <logger level="info" name="roleSiftingLogger" additivity="false">
+        <appender-ref ref="roleSiftingAppender" />
+    </logger>
+	
+    <logger level="info" name="colorLogger" additivity="false">
+        <appender-ref ref="colorAppender" />
+    </logger>
+    
+    <logger level="info" name="ignoredColorLogger">
+        <appender-ref ref="colorAppender" />
+    </logger>
+    
+    <logger level="info" name="levelFilterLogger" additivity="false">
+        <appender-ref ref="STDOUT_LEVEL_FILTER_APPENDER" />
+    </logger>
+    
+    <logger level="info" name="thresholdFilterLogger" additivity="false">
+        <appender-ref ref="STDOUT_THRESHOLD_FILTER_APPENDER" />
+    </logger>
+    
+    <logger level="info" name="evaluatorFilterLogger" additivity="false">
+        <appender-ref ref="STDOUT_EVALUATOR_FILTER_APPENDER" />
+    </logger>
+    
+    <!-- configure root logger -->
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+	
+    <!-- configure root logger conditionally -->	
+    <property scope="context" resource="application.properties" />
+	
+    <if condition='property("env").equals("dev")'>
+        <then>
+            <root level="TRACE">
+                <appender-ref ref="STDOUT" />
+            </root>
+        </then>
+    </if>
+
+</configuration>

guest/logback-example/src/test/java/com/stackify/services/EmployeeServiceTest.java

@@ -0,0 +1,74 @@
+package com.stackify.services;
+
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.slf4j.MDC;
+
+import com.stackify.models.Employee;
+
+import ch.qos.logback.classic.Level;
+
+public class EmployeeServiceTest {
+    private static final Logger logger = LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
+
+    private EmployeeService employeeService = new EmployeeService();
+
+    @Test
+    public void testAppenders() {
+        Logger rollingFileLogger = LoggerFactory.getLogger("rollingFileLogger");
+        rollingFileLogger.info("Testing rolling file logger");
+
+        MDC.put("userRole", "ADMIN");
+        Logger siftingLogger = LoggerFactory.getLogger("roleSiftingLogger");
+        siftingLogger.info("Admin Action");
+    }
+
+    @Test
+    public void testLayouts() {
+        Logger htmlLogger = LoggerFactory.getLogger("htmlLogger");
+        htmlLogger.error("Employee Information Update Failed");
+        htmlLogger.info("New Account Created");
+        
+        Logger colorLogger = LoggerFactory.getLogger("colorLogger");
+        colorLogger.error("Employee Information Update Failed");
+        colorLogger.info("New Account Created");
+    }
+
+    @Test
+    public void testLogLevel() {
+        ch.qos.logback.classic.Logger rollingFileLogger = (ch.qos.logback.classic.Logger) LoggerFactory.getLogger("rollingFileLogger");
+        rollingFileLogger.setLevel(Level.DEBUG);
+        rollingFileLogger.debug("Testing Log Level");
+    }
+
+    @Test
+    public void testParameter() {
+        Employee employee = new Employee("john@gmail.com", "John", 2000);
+        if (logger.isDebugEnabled()) {
+            logger.debug("The bonus for employee: " + employee.getName() + " is " + employeeService.calculateBonus(employee));
+        }
+        logger.debug("The bonus for employee {} is {}", employee.getName(), employeeService.calculateBonus(employee));
+    }
+
+    @Test
+    public void testFilters() {
+        Logger levelFilterLogger = LoggerFactory.getLogger("levelFilterLogger");
+        levelFilterLogger.error("Employee Information Update Failed");
+        Logger thresholdFilterLogger = LoggerFactory.getLogger("thresholdFilterLogger");
+        thresholdFilterLogger.trace("Employee record inserted");
+        Logger evaluatorFilterLogger = LoggerFactory.getLogger("evaluatorFilterLogger");
+        evaluatorFilterLogger.debug("Employee account deactivated");
+    }
+
+    @Test
+    public void testIgnoredLogger() {
+        Logger colorLogger = LoggerFactory.getLogger("ignoredColorLogger");
+        colorLogger.info("Ignored Log Message");
+    }
+
+    @Test
+    public void testConditionalConfiguration() {
+        logger.trace("Employee record updated");
+    }
+}

guest/thread-pools/pom.xml

@@ -0,0 +1,28 @@
+<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.stackify</groupId>
+	<artifactId>thread-pools</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+
+	<dependencies>
+		<dependency>
+			<groupId>ch.qos.logback</groupId>
+			<artifactId>logback-classic</artifactId>
+			<version>1.2.3</version>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.5.1</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+</project>

guest/thread-pools/src/main/java/com/stackify/models/Employee.java

@@ -0,0 +1,28 @@
+package com.stackify.models;
+
+public class Employee {
+    private String name;
+    private double salary;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public void setSalary(double salary) {
+        this.salary = salary;
+    }
+
+    public Employee(String name, double salary) {
+        super();
+        this.name = name;
+        this.salary = salary;
+    }
+}

guest/thread-pools/src/main/java/com/stackify/services/EmployeeService.java

@@ -0,0 +1,9 @@
+package com.stackify.services;
+
+import com.stackify.models.Employee;
+
+public class EmployeeService {
+    public double calculateBonus(Employee employee) {
+        return 0.1 * employee.getSalary();
+    }
+}

guest/thread-pools/src/main/java/com/stackify/threadpools/FactorialTask.java

@@ -0,0 +1,64 @@
+package com.stackify.threadpools;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.ForkJoinTask;
+import java.util.concurrent.RecursiveTask;
+import java.util.stream.IntStream;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class FactorialTask extends RecursiveTask<BigInteger> {
+    
+    private static final Logger logger = LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
+
+    private static final long serialVersionUID = 1L;
+
+    private int start = 1;
+    private int n;
+
+    private static final int THRESHOLD = 20;
+
+    public FactorialTask(int n) {
+        this.n = n;
+    }
+
+    public FactorialTask(int start, int n) {
+        logger.info("New FactorialTask Created");
+        this.start = start;
+        this.n = n;
+    }
+
+    @Override
+    protected BigInteger compute() {        
+        if ((n - start) >= THRESHOLD) {
+            return ForkJoinTask.invokeAll(createSubtasks())
+                .stream()
+                .map(ForkJoinTask::join)
+                .reduce(BigInteger.ONE, BigInteger::multiply);
+        } else {
+            return calculate(start, n);
+        }
+    }
+
+    private Collection<FactorialTask> createSubtasks() {
+        List<FactorialTask> dividedTasks = new ArrayList<>();
+
+        int mid = (start + n) / 2;
+
+        dividedTasks.add(new FactorialTask(start, mid));
+        dividedTasks.add(new FactorialTask(mid + 1, n));
+        return dividedTasks;
+    }
+
+    private BigInteger calculate(int start, int n) {
+        logger.info("Calculate factorial from " + start + " to " + n);
+        return IntStream.rangeClosed(start, n)
+            .mapToObj(BigInteger::valueOf)
+            .reduce(BigInteger.ONE, BigInteger::multiply);
+    }
+
+}

guest/thread-pools/src/main/java/com/stackify/threadpools/ThreadsApplication.java

@@ -0,0 +1,102 @@
+package com.stackify.threadpools;
+
+import java.math.BigInteger;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ForkJoinPool;
+import java.util.concurrent.Future;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.stackify.models.Employee;
+import com.stackify.services.EmployeeService;
+
+public class ThreadsApplication {
+
+    private static final Logger logger = LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
+
+    public static void main(String[] args) {
+         testExecutor();
+         testExecutorService();
+         testScheduledExecutorService();
+         testThreadPoolExecutor();
+        testForkJoinPool();
+    }
+
+    private static EmployeeService employeeService = new EmployeeService();
+
+    public static void testExecutor() {
+        Executor executor = Executors.newSingleThreadExecutor();
+        executor.execute(() -> System.out.println("Single thread pool test"));
+    }
+
+    public static void testExecutorService() {
+
+        Employee employee = new Employee("John", 2000);
+
+        ExecutorService executor = Executors.newFixedThreadPool(10);
+
+        Callable<Double> callableTask = () -> {
+            return employeeService.calculateBonus(employee);
+        };
+        Future<Double> future = executor.submit(callableTask);
+
+        try {
+            if (future.isDone()) {
+                double result = future.get();
+                System.out.println("Bonus is:" + result);
+            }
+        } catch (InterruptedException | ExecutionException e) {
+            e.printStackTrace();
+        }
+
+        executor.shutdown();
+    }
+
+    public static void testScheduledExecutorService() {
+        Employee employee = new Employee("John", 2000);
+
+        ScheduledExecutorService executor = Executors.newScheduledThreadPool(10);
+
+        Callable<Double> callableTask = () -> {
+            return employeeService.calculateBonus(employee);
+        };
+
+        Future<Double> futureScheduled = executor.schedule(callableTask, 2, TimeUnit.MILLISECONDS);
+
+        try {
+            System.out.println("Bonus:" + futureScheduled.get());
+        } catch (InterruptedException | ExecutionException e) {
+            e.printStackTrace();
+        }
+
+        executor.scheduleAtFixedRate(() -> System.out.println("Fixed Rate Scheduled"), 2, 2000, TimeUnit.MILLISECONDS);
+        executor.scheduleWithFixedDelay(() -> System.out.println("Fixed Delay Scheduled"), 2, 2000, TimeUnit.MILLISECONDS);
+    }
+
+    public static void testThreadPoolExecutor() {
+        ThreadPoolExecutor fixedPoolExecutor = (ThreadPoolExecutor) Executors.newFixedThreadPool(10);
+        ThreadPoolExecutor cachedPoolExecutor = (ThreadPoolExecutor) Executors.newCachedThreadPool();
+
+        ThreadPoolExecutor executor = new ThreadPoolExecutor(4, 6, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>());
+        executor.setMaximumPoolSize(8);
+
+        ScheduledThreadPoolExecutor scheduledExecutor = (ScheduledThreadPoolExecutor) Executors.newScheduledThreadPool(5);
+    }
+
+    public static void testForkJoinPool() {
+        ForkJoinPool pool = ForkJoinPool.commonPool();
+        logger.info("Thread Pool Created");
+        BigInteger result = pool.invoke(new FactorialTask(100));
+        System.out.println(result.toString());
+    }
+}

jackson/pom.xml

@@ -129,7 +129,7 @@
 
     <properties>
         <!-- marshalling -->
-        <jackson.version>2.8.7</jackson.version>
+        <jackson.version>2.9.0</jackson.version>
 
         <!-- util -->
         <guava.version>19.0</guava.version>

jackson/src/main/java/com/baeldung/jackson/deserialization/jacksoninject/Author.java

@@ -9,7 +9,8 @@ public class Author extends Person {
 
     List<Item> items = new ArrayList<>();
 
-    public Author(){}
+    public Author() {
+    }
 
     public Author(String firstName, String lastName) {
         super(firstName, lastName);

jackson/src/main/java/com/baeldung/jackson/deserialization/jacksoninject/Person.java

@@ -11,7 +11,7 @@ public class Person {
     private String firstName;
     private String lastName;
 
-    public Person(){
+    public Person() {
 
     }
 

jackson/src/main/java/com/baeldung/jackson/deserialization/jsoncreator/Author.java

@@ -1,6 +1,5 @@
 package com.baeldung.jackson.deserialization.jsoncreator;
 
-
 import com.baeldung.jackson.domain.Person;
 import com.baeldung.jackson.domain.Item;
 import com.fasterxml.jackson.annotation.JsonCreator;
@@ -14,9 +13,7 @@ public class Author extends Person {
     List<Item> items = new ArrayList<>();
 
     @JsonCreator
-    public Author(
-            @JsonProperty("christianName") String firstName,
-            @JsonProperty("surname") String lastName) {
+    public Author(@JsonProperty("christianName") String firstName, @JsonProperty("surname") String lastName) {
         super(firstName, lastName);
     }
 

jackson/src/main/java/com/baeldung/jackson/deserialization/jsondeserialize/Book.java

@@ -13,7 +13,8 @@ public class Book extends Item {
     private Date published;
     private BigDecimal pages;
 
-    public Book() {}
+    public Book() {
+    }
 
     public Book(String title, Author author) {
         super(title, author);

jackson/src/main/java/com/baeldung/jackson/deserialization/jsondeserialize/CustomDateDeserializer.java

@@ -11,8 +11,7 @@ import java.util.Date;
 
 public class CustomDateDeserializer extends StdDeserializer<Date> {
 
-    private static SimpleDateFormat formatter =
-            new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
+    private static SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
 
     public CustomDateDeserializer() {
         this(null);
@@ -23,8 +22,7 @@ public class CustomDateDeserializer extends StdDeserializer<Date> {
     }
 
     @Override
-    public Date deserialize(JsonParser jsonparser, DeserializationContext context)
-            throws IOException {
+    public Date deserialize(JsonParser jsonparser, DeserializationContext context) throws IOException {
         String date = jsonparser.getText();
         try {
             return formatter.parse(date);

jackson/src/main/java/com/baeldung/jackson/deserialization/jsondeserialize/Item.java

@@ -19,7 +19,8 @@ public class Item {
     private List<Person> authors = new ArrayList<>();
     private float price;
 
-    public Item(){}
+    public Item() {
+    }
 
     public Item(String title, Author author) {
         this.id = UUID.randomUUID();

jackson/src/main/java/com/baeldung/jackson/deserialization/jsonsetter/Author.java

@@ -18,7 +18,8 @@ public class Author extends Person {
 
     private List<Item> items = new ArrayList<>();
 
-    public Author(){}
+    public Author() {
+    }
 
     public Author(String firstName, String lastName) {
         super(firstName, lastName);

jackson/src/main/java/com/baeldung/jackson/domain/Book.java

@@ -15,7 +15,7 @@ public class Book extends Item {
     private Date published;
     private BigDecimal pages;
 
-    public Book(){
+    public Book() {
     }
 
     public Book(String title, Author author) {

jackson/src/main/java/com/baeldung/jackson/domain/Course.java

@@ -10,7 +10,9 @@ import java.util.List;
  */
 public class Course extends Item {
 
-    public enum Medium {CLASSROOM, ONLINE}
+    public enum Medium {
+        CLASSROOM, ONLINE
+    }
 
     public enum Level {
         BEGINNER("Beginner", 1), INTERMEDIATE("Intermediate", 2), ADVANCED("Advanced", 3);

jackson/src/main/java/com/baeldung/jackson/domain/Item.java

@@ -17,7 +17,8 @@ public class Item {
     private List<Person> authors = new ArrayList<>();
     private float price;
 
-    public Item(){}
+    public Item() {
+    }
 
     public Item(String title, Author author) {
         this.id = UUID.randomUUID();

jackson/src/main/java/com/baeldung/jackson/domain/Person.java

@@ -14,7 +14,8 @@ public class Person {
     private String firstName;
     private String lastName;
 
-    public Person(){}
+    public Person() {
+    }
 
     public Person(String firstName, String lastName) {
         this.id = UUID.randomUUID();

jackson/src/main/java/com/baeldung/jackson/entities/ClassWithAMap.java

@@ -9,16 +9,16 @@ import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 
 public class ClassWithAMap {
 
-	@JsonProperty("map")
-	@JsonDeserialize(keyUsing = MyPairDeserializer.class)
-	private final Map<MyPair, String> map;
+    @JsonProperty("map")
+    @JsonDeserialize(keyUsing = MyPairDeserializer.class)
+    private final Map<MyPair, String> map;
 
-	@JsonCreator
-	public ClassWithAMap(Map<MyPair, String> map) {
-		this.map = map;
-	}
+    @JsonCreator
+    public ClassWithAMap(Map<MyPair, String> map) {
+        this.map = map;
+    }
 
-	public Map<MyPair, String> getMap() {
-		return map;
-	}
+    public Map<MyPair, String> getMap() {
+        return map;
+    }
 }

jackson/src/main/java/com/baeldung/jackson/entities/MyPair.java

@@ -4,77 +4,77 @@ import com.fasterxml.jackson.annotation.JsonValue;
 
 public class MyPair {
 
-	private String first;
-	private String second;
+    private String first;
+    private String second;
 
-	public MyPair(String first, String second) {
-		this.first = first;
-		this.second = second;
-	}
+    public MyPair(String first, String second) {
+        this.first = first;
+        this.second = second;
+    }
 
-	public MyPair(String both) {
-		String[] pairs = both.split("and");
-		this.first = pairs[0].trim();
-		this.second = pairs[1].trim();
-	}
+    public MyPair(String both) {
+        String[] pairs = both.split("and");
+        this.first = pairs[0].trim();
+        this.second = pairs[1].trim();
+    }
 
-	@Override
-	@JsonValue
-	public String toString() {
-		return first + " and " + second;
-	}
+    @Override
+    @JsonValue
+    public String toString() {
+        return first + " and " + second;
+    }
 
-	@Override
-	public int hashCode() {
-		final int prime = 31;
-		int result = 1;
-		result = prime * result + ((first == null) ? 0 : first.hashCode());
-		result = prime * result + ((second == null) ? 0 : second.hashCode());
-		return result;
-	}
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((first == null) ? 0 : first.hashCode());
+        result = prime * result + ((second == null) ? 0 : second.hashCode());
+        return result;
+    }
 
-	@Override
-	public boolean equals(Object obj) {
-		if (this == obj) {
-			return true;
-		}
-		if (obj == null) {
-			return false;
-		}
-		if (!(obj instanceof MyPair)) {
-			return false;
-		}
-		MyPair other = (MyPair) obj;
-		if (first == null) {
-			if (other.first != null) {
-				return false;
-			}
-		} else if (!first.equals(other.first)) {
-			return false;
-		}
-		if (second == null) {
-			if (other.second != null) {
-				return false;
-			}
-		} else if (!second.equals(other.second)) {
-			return false;
-		}
-		return true;
-	}
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (!(obj instanceof MyPair)) {
+            return false;
+        }
+        MyPair other = (MyPair) obj;
+        if (first == null) {
+            if (other.first != null) {
+                return false;
+            }
+        } else if (!first.equals(other.first)) {
+            return false;
+        }
+        if (second == null) {
+            if (other.second != null) {
+                return false;
+            }
+        } else if (!second.equals(other.second)) {
+            return false;
+        }
+        return true;
+    }
 
-	public String getFirst() {
-		return first;
-	}
+    public String getFirst() {
+        return first;
+    }
 
-	public void setFirst(String first) {
-		this.first = first;
-	}
+    public void setFirst(String first) {
+        this.first = first;
+    }
 
-	public String getSecond() {
-		return second;
-	}
+    public String getSecond() {
+        return second;
+    }
 
-	public void setSecond(String second) {
-		this.second = second;
-	}
+    public void setSecond(String second) {
+        this.second = second;
+    }
 }

jackson/src/main/java/com/baeldung/jackson/format/User.java

@@ -13,28 +13,25 @@ public class User extends Person {
     private String firstName;
     private String lastName;
 
-    @JsonFormat(shape = JsonFormat.Shape.STRING,
-		pattern = "yyyy-MM-dd@HH:mm:ss.SSSZ")
+    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd@HH:mm:ss.SSSZ")
     private Date createdDate;
 
-    public User(String firstName,String lastName) {
-	super(firstName, lastName);
-	this.createdDate = new Date();
+    public User(String firstName, String lastName) {
+        super(firstName, lastName);
+        this.createdDate = new Date();
     }
 
     public Date getCreatedDate() {
         return createdDate;
     }
 
-    @JsonFormat(shape = JsonFormat.Shape.STRING,
-		pattern = "yyyy-MM-dd@HH:mm:ss.SSSZ",
-		locale = "en_GB")
+    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd@HH:mm:ss.SSSZ", locale = "en_GB")
     public Date getCurrentDate() {
-	return new Date();
+        return new Date();
     }
 
     @JsonFormat(shape = JsonFormat.Shape.NUMBER)
     public Date getDateNum() {
-	return new Date();
+        return new Date();
     }
 }

jackson/src/main/java/com/baeldung/jackson/inclusion/jsonignore/Person.java

@@ -17,7 +17,8 @@ public class Person {
     private String firstName;
     private String lastName;
 
-    public Person(){}
+    public Person() {
+    }
 
     public Person(String firstName, String lastName) {
         this.id = UUID.randomUUID();

jackson/src/main/java/com/baeldung/jackson/inclusion/jsonignoreproperties/Course.java

@@ -12,10 +12,12 @@ import java.util.List;
  * @author Alex Theedom www.readlearncode.com
  * @version 1.0
  */
-@JsonIgnoreProperties({"medium"})
+@JsonIgnoreProperties({ "medium" })
 public class Course extends Item {
 
-    public enum Medium {CLASSROOM, ONLINE}
+    public enum Medium {
+        CLASSROOM, ONLINE
+    }
 
     public enum Level {
         BEGINNER("Beginner", 1), INTERMEDIATE("Intermediate", 2), ADVANCED("Advanced", 3);

jackson/src/main/java/com/baeldung/jackson/inheritance/ItemIdAddedToUser.java

@@ -12,10 +12,7 @@ public class ItemIdAddedToUser extends Event {
     private final Long quantity;
 
     @JsonCreator
-    public ItemIdAddedToUser(@JsonProperty("id") String id,
-                             @JsonProperty("timestamp") Long timestamp,
-                             @JsonProperty("itemId") String itemId,
-                             @JsonProperty("quantity") Long quantity) {
+    public ItemIdAddedToUser(@JsonProperty("id") String id, @JsonProperty("timestamp") Long timestamp, @JsonProperty("itemId") String itemId, @JsonProperty("quantity") Long quantity) {
         super(id, timestamp);
         this.itemId = itemId;
         this.quantity = quantity;

jackson/src/main/java/com/baeldung/jackson/inheritance/ItemIdRemovedFromUser.java

@@ -10,10 +10,7 @@ public class ItemIdRemovedFromUser extends Event {
     private final Long quantity;
 
     @JsonCreator
-    public ItemIdRemovedFromUser(@JsonProperty("id") String id,
-                                 @JsonProperty("timestamp") Long timestamp,
-                                 @JsonProperty("itemId") String itemId,
-                                 @JsonProperty("quantity") Long quantity) {
+    public ItemIdRemovedFromUser(@JsonProperty("id") String id, @JsonProperty("timestamp") Long timestamp, @JsonProperty("itemId") String itemId, @JsonProperty("quantity") Long quantity) {
         super(id, timestamp);
         this.itemId = itemId;
         this.quantity = quantity;

jackson/src/main/java/com/baeldung/jackson/miscellaneous/custom/Course.java

@@ -13,7 +13,9 @@ import java.util.List;
 @CustomCourseAnnotation
 public class Course extends Item {
 
-    public enum Medium {CLASSROOM, ONLINE}
+    public enum Medium {
+        CLASSROOM, ONLINE
+    }
 
     public enum Level {
         BEGINNER("Beginner", 1), INTERMEDIATE("Intermediate", 2), ADVANCED("Advanced", 3);

jackson/src/main/java/com/baeldung/jackson/miscellaneous/custom/CustomCourseAnnotation.java

@@ -14,7 +14,7 @@ import java.lang.annotation.RetentionPolicy;
 @Retention(RetentionPolicy.RUNTIME)
 @JacksonAnnotationsInside
 @JsonInclude(JsonInclude.Include.NON_NULL)
-@JsonPropertyOrder({"title", "price", "id", "duration", "authors", "level"})
-@JsonIgnoreProperties({"prerequisite"})
+@JsonPropertyOrder({ "title", "price", "id", "duration", "authors", "level" })
+@JsonIgnoreProperties({ "prerequisite" })
 public @interface CustomCourseAnnotation {
 }

jackson/src/main/java/com/baeldung/jackson/miscellaneous/custom/Item.java

@@ -20,7 +20,8 @@ public class Item {
     private List<Person> authors = new ArrayList<>();
     private float price;
 
-    public Item(){}
+    public Item() {
+    }
 
     public Item(String title, Author author) {
         this.id = UUID.randomUUID();

jackson/src/main/java/com/baeldung/jackson/miscellaneous/disable/Author.java

@@ -16,7 +16,7 @@ import java.util.List;
  * @version 1.0
  */
 @JsonInclude(JsonInclude.Include.NON_NULL)
-@JsonPropertyOrder({"lastName", "items", "firstName", "id"})
+@JsonPropertyOrder({ "lastName", "items", "firstName", "id" })
 public class Author extends Person {
 
     @JsonIgnore

jackson/src/main/java/com/baeldung/jackson/polymorphism/Order.java

@@ -18,12 +18,8 @@ public class Order {
     private Type type;
     private int internalAudit;
 
-    @JsonTypeInfo(use = JsonTypeInfo.Id.NAME,
-            include = JsonTypeInfo.As.PROPERTY,
-            property = "ordertype")
-    @JsonSubTypes({
-            @JsonSubTypes.Type(value = InternalType.class, name = "internal")
-    })
+    @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "ordertype")
+    @JsonSubTypes({ @JsonSubTypes.Type(value = InternalType.class, name = "internal") })
     public static class Type {
         public long id;
         public String name;

jackson/src/main/java/com/baeldung/jackson/serialization/ActorJacksonSerializer.java

@@ -24,8 +24,11 @@ public class ActorJacksonSerializer extends StdSerializer<ActorJackson> {
         jsonGenerator.writeStartObject();
         jsonGenerator.writeStringField("imdbId", actor.getImdbId());
         jsonGenerator.writeObjectField("dateOfBirth", actor.getDateOfBirth() != null ? sdf.format(actor.getDateOfBirth()) : null);
-        jsonGenerator.writeNumberField("N° Film: ", actor.getFilmography() != null ? actor.getFilmography().size() : null);
-        jsonGenerator.writeStringField("filmography", actor.getFilmography().stream().collect(Collectors.joining("-")));
+        jsonGenerator.writeNumberField("N° Film: ", actor.getFilmography() != null ? actor.getFilmography()
+            .size() : null);
+        jsonGenerator.writeStringField("filmography", actor.getFilmography()
+            .stream()
+            .collect(Collectors.joining("-")));
         jsonGenerator.writeEndObject();
     }
 }

jackson/src/main/java/com/baeldung/jackson/serialization/MyPairDeserializer.java

@@ -9,10 +9,9 @@ import com.fasterxml.jackson.databind.KeyDeserializer;
 
 public class MyPairDeserializer extends KeyDeserializer {
 
-	@Override
-	public MyPair deserializeKey(String key, DeserializationContext ctxt)
-			throws IOException, JsonProcessingException {
+    @Override
+    public MyPair deserializeKey(String key, DeserializationContext ctxt) throws IOException, JsonProcessingException {
 
-		return new MyPair(key);
-	}
+        return new MyPair(key);
+    }
 }

jackson/src/main/java/com/baeldung/jackson/serialization/MyPairSerializer.java

@@ -12,14 +12,12 @@ import com.fasterxml.jackson.databind.SerializerProvider;
 
 public class MyPairSerializer extends JsonSerializer<MyPair> {
 
-	private final ObjectMapper mapper = new ObjectMapper();
+    private final ObjectMapper mapper = new ObjectMapper();
 
-	@Override
-	public void serialize(MyPair value, JsonGenerator gen,
-			SerializerProvider serializers) throws IOException,
-			JsonProcessingException {
-		StringWriter writer = new StringWriter();
-		mapper.writeValue(writer, value);
-		gen.writeFieldName(writer.toString());
-	}
+    @Override
+    public void serialize(MyPair value, JsonGenerator gen, SerializerProvider serializers) throws IOException, JsonProcessingException {
+        StringWriter writer = new StringWriter();
+        mapper.writeValue(writer, value);
+        gen.writeFieldName(writer.toString());
+    }
 }

jackson/src/main/java/com/baeldung/jackson/serialization/jsongetter/Author.java

@@ -1,6 +1,5 @@
 package com.baeldung.jackson.serialization.jsongetter;
 
-
 import com.baeldung.jackson.domain.Item;
 import com.baeldung.jackson.domain.Person;
 import com.fasterxml.jackson.annotation.JsonGetter;

jackson/src/main/java/com/baeldung/jackson/serialization/jsonpropertyorder/Author.java

@@ -1,6 +1,5 @@
 package com.baeldung.jackson.serialization.jsonpropertyorder;
 
-
 import com.baeldung.jackson.domain.Item;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
@@ -13,7 +12,7 @@ import java.util.List;
  * @author Alex Theedom www.readlearncode.com
  * @version 1.0
  */
-@JsonPropertyOrder({"items", "firstName", "lastName", "id"})
+@JsonPropertyOrder({ "items", "firstName", "lastName", "id" })
 public class Author extends Person {
 
     List<Item> items = new ArrayList<>();

jackson/src/main/java/com/baeldung/jackson/serialization/jsonserialize/Book.java

@@ -19,7 +19,8 @@ public class Book extends Item {
     private Date published;
     private BigDecimal pages;
 
-    public Book(){}
+    public Book() {
+    }
 
     public Book(String title, Author author) {
         super(title, author);

jackson/src/main/java/com/baeldung/jackson/serialization/jsonserialize/CustomDateSerializer.java

@@ -17,8 +17,7 @@ import java.util.Date;
  */
 public class CustomDateSerializer extends StdSerializer<Date> {
 
-    private static SimpleDateFormat formatter =
-            new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
+    private static SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
 
     public CustomDateSerializer() {
         this(null);
@@ -29,8 +28,7 @@ public class CustomDateSerializer extends StdSerializer<Date> {
     }
 
     @Override
-    public void serialize(Date value, JsonGenerator gen, SerializerProvider arg2)
-            throws IOException, JsonProcessingException {
+    public void serialize(Date value, JsonGenerator gen, SerializerProvider arg2) throws IOException, JsonProcessingException {
         gen.writeString(formatter.format(value));
     }
 }

jackson/src/main/java/com/baeldung/jackson/serialization/jsonserialize/Item.java

@@ -19,7 +19,8 @@ public class Item {
     private List<Person> authors = new ArrayList<>();
     private float price;
 
-    public Item(){}
+    public Item() {
+    }
 
     public Item(String title, Author author) {
         this.id = UUID.randomUUID();

jackson/src/main/java/com/baeldung/jackson/serialization/jsonvalue/Course.java

@@ -14,7 +14,9 @@ import java.util.List;
  */
 public class Course extends Item {
 
-    public enum Medium {CLASSROOM, ONLINE}
+    public enum Medium {
+        CLASSROOM, ONLINE
+    }
 
     public enum Level {
         BEGINNER("Beginner", 1), INTERMEDIATE("Intermediate", 2), ADVANCED("Advanced", 3);

jackson/src/test/java/com/baeldung/jackson/annotation/extra/ExtraAnnotationUnitTest.java

@@ -47,9 +47,10 @@ public class ExtraAnnotationUnitTest {
         ObjectMapper mapper = new ObjectMapper();
 
         BeanWithoutAppend bean = new BeanWithoutAppend(2, "Bean Without Append Annotation");
-        ObjectWriter writer = mapper.writerFor(BeanWithoutAppend.class).withAttribute("version", "1.0");
+        ObjectWriter writer = mapper.writerFor(BeanWithoutAppend.class)
+            .withAttribute("version", "1.0");
         String jsonString = writer.writeValueAsString(bean);
-        
+
         assertThat(jsonString, not(containsString("version")));
         assertThat(jsonString, not(containsString("1.0")));
     }
@@ -59,9 +60,10 @@ public class ExtraAnnotationUnitTest {
         ObjectMapper mapper = new ObjectMapper();
 
         BeanWithAppend bean = new BeanWithAppend(2, "Bean With Append Annotation");
-        ObjectWriter writer = mapper.writerFor(BeanWithAppend.class).withAttribute("version", "1.0");
+        ObjectWriter writer = mapper.writerFor(BeanWithAppend.class)
+            .withAttribute("version", "1.0");
         String jsonString = writer.writeValueAsString(bean);
-        
+
         assertThat(jsonString, containsString("version"));
         assertThat(jsonString, containsString("1.0"));
     }
@@ -71,7 +73,7 @@ public class ExtraAnnotationUnitTest {
         ObjectMapper mapper = new ObjectMapper();
         NamingBean bean = new NamingBean(3, "Naming Bean");
         String jsonString = mapper.writeValueAsString(bean);
-        
+
         assertThat(jsonString, containsString("bean_name"));
     }
 

jackson/src/test/java/com/baeldung/jackson/annotation/extra/IdentityReferenceBeans.java

@@ -4,7 +4,6 @@ import com.fasterxml.jackson.annotation.JsonIdentityInfo;
 import com.fasterxml.jackson.annotation.JsonIdentityReference;
 import com.fasterxml.jackson.annotation.ObjectIdGenerators;
 
-
 public class IdentityReferenceBeans {
     @JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
     public static class BeanWithoutIdentityReference {
@@ -32,7 +31,7 @@ public class IdentityReferenceBeans {
             this.name = name;
         }
     }
-    
+
     @JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
     @JsonIdentityReference(alwaysAsId = true)
     public static class BeanWithIdentityReference {

jackson/src/test/java/com/baeldung/jackson/bidirection/CustomListSerializer.java

@@ -20,6 +20,7 @@ public class CustomListSerializer extends StdSerializer<List<ItemWithSerializer>
     public CustomListSerializer(final Class<List<ItemWithSerializer>> t) {
         super(t);
     }
+
     @Override
     public void serialize(final List<ItemWithSerializer> items, final JsonGenerator generator, final SerializerProvider provider) throws IOException, JsonProcessingException {
         final List<Integer> ids = new ArrayList<Integer>();

jackson/src/test/java/com/baeldung/jackson/date/CustomLocalDateTimeSerializer.java

@@ -11,7 +11,6 @@ import com.fasterxml.jackson.databind.ser.std.StdSerializer;
 
 public class CustomLocalDateTimeSerializer extends StdSerializer<LocalDateTime> {
 
-
     private static final long serialVersionUID = -7449444168934819290L;
     private static DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm");
 

jackson/src/test/java/com/baeldung/jackson/deserialization/ItemDeserializer.java

@@ -28,9 +28,11 @@ public class ItemDeserializer extends StdDeserializer<Item> {
      */
     @Override
     public Item deserialize(final JsonParser jp, final DeserializationContext ctxt) throws IOException, JsonProcessingException {
-        final JsonNode node = jp.getCodec().readTree(jp);
+        final JsonNode node = jp.getCodec()
+            .readTree(jp);
         final int id = (Integer) ((IntNode) node.get("id")).numberValue();
-        final String itemName = node.get("itemName").asText();
+        final String itemName = node.get("itemName")
+            .asText();
         final int userId = (Integer) ((IntNode) node.get("createdBy")).numberValue();
 
         return new Item(id, itemName, new User(userId, null));

jackson/src/test/java/com/baeldung/jackson/deserialization/ItemDeserializerOnClass.java

@@ -28,9 +28,11 @@ public class ItemDeserializerOnClass extends StdDeserializer<ItemWithSerializer>
      */
     @Override
     public ItemWithSerializer deserialize(final JsonParser jp, final DeserializationContext ctxt) throws IOException, JsonProcessingException {
-        final JsonNode node = jp.getCodec().readTree(jp);
+        final JsonNode node = jp.getCodec()
+            .readTree(jp);
         final int id = (Integer) ((IntNode) node.get("id")).numberValue();
-        final String itemName = node.get("itemName").asText();
+        final String itemName = node.get("itemName")
+            .asText();
         final int userId = (Integer) ((IntNode) node.get("owner")).numberValue();
 
         return new ItemWithSerializer(id, itemName, new User(userId, null));

jackson/src/test/java/com/baeldung/jackson/deserialization/JacksonMapDeserializeUnitTest.java

@@ -16,54 +16,49 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 
 public class JacksonMapDeserializeUnitTest {
 
-	private Map<MyPair, String> map;
-	private Map<MyPair, MyPair> cmap;
-	final ObjectMapper mapper = new ObjectMapper();
+    private Map<MyPair, String> map;
+    private Map<MyPair, MyPair> cmap;
+    final ObjectMapper mapper = new ObjectMapper();
 
-	@Test
-	public void whenSimpleMapDeserialize_thenCorrect()
-			throws JsonParseException, JsonMappingException, IOException {
+    @Test
+    public void whenSimpleMapDeserialize_thenCorrect() throws JsonParseException, JsonMappingException, IOException {
 
-		final String jsonInput = "{\"key\": \"value\"}";
-		TypeReference<HashMap<String, String>> typeRef = new TypeReference<HashMap<String, String>>() {
-		};
+        final String jsonInput = "{\"key\": \"value\"}";
+        TypeReference<HashMap<String, String>> typeRef = new TypeReference<HashMap<String, String>>() {
+        };
 
-		final Map<String, String> map = mapper.readValue(jsonInput, typeRef);
+        final Map<String, String> map = mapper.readValue(jsonInput, typeRef);
 
-		Assert.assertEquals("value", map.get("key"));
-	}
+        Assert.assertEquals("value", map.get("key"));
+    }
 
-	@Test
-	public void whenObjectStringMapDeserialize_thenCorrect()
-			throws JsonParseException, JsonMappingException, IOException {
+    @Test
+    public void whenObjectStringMapDeserialize_thenCorrect() throws JsonParseException, JsonMappingException, IOException {
 
-		final String jsonInput = "{\"Abbott and Costello\":\"Comedy\"}";
+        final String jsonInput = "{\"Abbott and Costello\":\"Comedy\"}";
 
-		TypeReference<HashMap<MyPair, String>> typeRef = new TypeReference<HashMap<MyPair, String>>() {
-		};
+        TypeReference<HashMap<MyPair, String>> typeRef = new TypeReference<HashMap<MyPair, String>>() {
+        };
 
-		map = mapper.readValue(jsonInput, typeRef);
+        map = mapper.readValue(jsonInput, typeRef);
 
-		Assert.assertEquals("Comedy", map.get(new MyPair("Abbott", "Costello")));
+        Assert.assertEquals("Comedy", map.get(new MyPair("Abbott", "Costello")));
 
-		ClassWithAMap classWithMap = mapper.readValue(jsonInput,
-				ClassWithAMap.class);
+        ClassWithAMap classWithMap = mapper.readValue(jsonInput, ClassWithAMap.class);
 
-		Assert.assertEquals("Comedy",
-				classWithMap.getMap().get(new MyPair("Abbott", "Costello")));
-	}
+        Assert.assertEquals("Comedy", classWithMap.getMap()
+            .get(new MyPair("Abbott", "Costello")));
+    }
 
-	@Test
-	public void whenObjectObjectMapDeserialize_thenCorrect()
-			throws JsonParseException, JsonMappingException, IOException {
+    @Test
+    public void whenObjectObjectMapDeserialize_thenCorrect() throws JsonParseException, JsonMappingException, IOException {
 
-		final String jsonInput = "{\"Abbott and Costello\" : \"Comedy and 1940s\"}";
-		TypeReference<HashMap<MyPair, MyPair>> typeRef = new TypeReference<HashMap<MyPair, MyPair>>() {
-		};
+        final String jsonInput = "{\"Abbott and Costello\" : \"Comedy and 1940s\"}";
+        TypeReference<HashMap<MyPair, MyPair>> typeRef = new TypeReference<HashMap<MyPair, MyPair>>() {
+        };
 
-		cmap = mapper.readValue(jsonInput, typeRef);
+        cmap = mapper.readValue(jsonInput, typeRef);
 
-		Assert.assertEquals(new MyPair("Comedy", "1940s"),
-				cmap.get(new MyPair("Abbott", "Costello")));
-	}
+        Assert.assertEquals(new MyPair("Comedy", "1940s"), cmap.get(new MyPair("Abbott", "Costello")));
+    }
 }

jackson/src/test/java/com/baeldung/jackson/deserialization/jacksoninject/JacksonInjectUnitTest.java

@@ -27,7 +27,9 @@ public class JacksonInjectUnitTest {
 
         // act
         InjectableValues inject = new InjectableValues.Std().addValue(UUID.class, id);
-        Author author = new ObjectMapper().reader(inject).forType(Author.class).readValue(authorJson);
+        Author author = new ObjectMapper().reader(inject)
+            .forType(Author.class)
+            .readValue(authorJson);
 
         // assert
         assertThat(author.getId()).isEqualTo(id);

jackson/src/test/java/com/baeldung/jackson/deserialization/jsonanysetter/JsonAnySetterUnitTest.java

@@ -23,15 +23,28 @@ public class JsonAnySetterUnitTest {
         String json = "{\"USA\":10.00,\"UK\":15.00,\"China\":23.00,\"Brazil\":12.00,\"France\":8.00,\"Russia\":18.00}";
 
         // act
-        Inventory inventory = new ObjectMapper().readerFor(Inventory.class).readValue(json);
+        Inventory inventory = new ObjectMapper().readerFor(Inventory.class)
+            .readValue(json);
 
         // assert
-        assertThat(from(json).getMap(".").get("USA")).isEqualTo(inventory.getCountryDeliveryCost().get("USA"));
-        assertThat(from(json).getMap(".").get("UK")).isEqualTo(inventory.getCountryDeliveryCost().get("UK"));
-        assertThat(from(json).getMap(".").get("China")).isEqualTo(inventory.getCountryDeliveryCost().get("China"));
-        assertThat(from(json).getMap(".").get("Brazil")).isEqualTo(inventory.getCountryDeliveryCost().get("Brazil"));
-        assertThat(from(json).getMap(".").get("France")).isEqualTo(inventory.getCountryDeliveryCost().get("France"));
-        assertThat(from(json).getMap(".").get("Russia")).isEqualTo(inventory.getCountryDeliveryCost().get("Russia"));
+        assertThat(from(json).getMap(".")
+            .get("USA")).isEqualTo(inventory.getCountryDeliveryCost()
+                .get("USA"));
+        assertThat(from(json).getMap(".")
+            .get("UK")).isEqualTo(inventory.getCountryDeliveryCost()
+                .get("UK"));
+        assertThat(from(json).getMap(".")
+            .get("China")).isEqualTo(inventory.getCountryDeliveryCost()
+                .get("China"));
+        assertThat(from(json).getMap(".")
+            .get("Brazil")).isEqualTo(inventory.getCountryDeliveryCost()
+                .get("Brazil"));
+        assertThat(from(json).getMap(".")
+            .get("France")).isEqualTo(inventory.getCountryDeliveryCost()
+                .get("France"));
+        assertThat(from(json).getMap(".")
+            .get("Russia")).isEqualTo(inventory.getCountryDeliveryCost()
+                .get("Russia"));
 
     }
 }

jackson/src/test/java/com/baeldung/jackson/deserialization/jsoncreator/JsonCreatorUnitTest.java

@@ -20,14 +20,11 @@ public class JsonCreatorUnitTest {
     public void whenDeserializingUsingJsonCreator_thenCorrect() throws IOException {
 
         // arrange
-        String authorJson =
-                "{" +
-                "    \"christianName\": \"Alex\"," +
-                "    \"surname\": \"Theedom\"" +
-                "}";
+        String authorJson = "{" + "    \"christianName\": \"Alex\"," + "    \"surname\": \"Theedom\"" + "}";
 
         // act
-        final Author author = new ObjectMapper().readerFor(Author.class).readValue(authorJson);
+        final Author author = new ObjectMapper().readerFor(Author.class)
+            .readValue(authorJson);
 
         // assert
         assertThat(from(authorJson).getString("christianName")).isEqualTo(author.getFirstName());

jackson/src/test/java/com/baeldung/jackson/deserialization/jsondeserialize/JsonDeserializeUnitTest.java

@@ -24,7 +24,8 @@ public class JsonDeserializeUnitTest {
         String bookJson = "{\"id\":\"957c43f2-fa2e-42f9-bf75-6e3d5bb6960a\",\"title\":\"Effective Java\",\"authors\":[{\"id\":\"9bcd817d-0141-42e6-8f04-e5aaab0980b6\",\"firstName\":\"Joshua\",\"lastName\":\"Bloch\"}],\"price\":0,\"published\":\"25-12-2017 13:30:25\",\"pages\":null,\"isbn\":null}";
 
         // act
-        Book book = new ObjectMapper().readerFor(Book.class).readValue(bookJson);
+        Book book = new ObjectMapper().readerFor(Book.class)
+            .readValue(bookJson);
 
         // assert
         SimpleDateFormat df = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");

jackson/src/test/java/com/baeldung/jackson/deserialization/jsonsetter/JsonSetterUnitTest.java

@@ -23,10 +23,13 @@ public class JsonSetterUnitTest {
         String json = "{\"firstName\":\"Alex\",\"lastName\":\"Theedom\",\"publications\":[{\"title\":\"Professional Java EE Design Patterns\"}]}";
 
         // act
-        Author author = new ObjectMapper().readerFor(Author.class).readValue(json);
+        Author author = new ObjectMapper().readerFor(Author.class)
+            .readValue(json);
 
         // assert
-        assertThat(from(json).getList("publications").size()).isEqualTo(author.getItems().size());
+        assertThat(from(json).getList("publications")
+            .size()).isEqualTo(author.getItems()
+                .size());
 
     }
 }

jackson/src/test/java/com/baeldung/jackson/dynamicIgnore/Address.java

@@ -1,6 +1,5 @@
 package com.baeldung.jackson.dynamicIgnore;
 
-
 public class Address implements Hidable {
     private String city;
     private String country;

jackson/src/test/java/com/baeldung/jackson/dynamicIgnore/Hidable.java

@@ -2,7 +2,6 @@ package com.baeldung.jackson.dynamicIgnore;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
-
 @JsonIgnoreProperties("hidden")
 public interface Hidable {
     boolean isHidden();