Merge remote-tracking branch 'upstream/master'

2018-10-10 18:22:40 +05:30
parent f916c468cd 53d22bebbc
commit 20f2d3a923
76 changed files with 2264 additions and 391 deletions
@@ -62,3 +62,5 @@ jmeter/src/main/resources/*-JMeter.csv
 **/dist
 **/tmp
 **/out-tsc
+**/nbproject/
+**/nb-configuration.xml
@@ -0,0 +1,41 @@
+package com.baeldung.algorithms.insertionsort;
+
+public class InsertionSort {
+
+    public static void insertionSortImperative(int[] input) {
+        for (int i = 1; i < input.length; i++) {
+            int key = input[i];
+            int j = i - 1;
+            while (j >= 0 && input[j] > key) {
+                input[j + 1] = input[j];
+                j = j - 1;
+            }
+            input[j + 1] = key;
+        }
+    }
+
+    public static void insertionSortRecursive(int[] input) {
+        insertionSortRecursive(input, input.length);
+    }
+
+    private static void insertionSortRecursive(int[] input, int i) {
+        // base case
+        if (i <= 1) {
+            return;
+        }
+
+        // sort the first i - 1 elements of the array
+        insertionSortRecursive(input, i - 1);
+
+        // then find the correct position of the element at position i
+        int key = input[i - 1];
+        int j = i - 2;
+        // shifting the elements from their position by 1
+        while (j >= 0 && input[j] > key) {
+            input[j + 1] = input[j];
+            j = j - 1;
+        }
+        // inserting the key at the appropriate position
+        input[j + 1] = key;
+    }
+}
@@ -98,7 +98,7 @@ public class FindKthLargest {

    private int randomPartition(Integer arr[], int left, int right) {
        int n = right - left + 1;
-        int pivot = (int) (Math.random()) % n;
+        int pivot = (int) (Math.random() * n);
        swap(arr, left + pivot, right);
        return partition(arr, left, right);
    }
@@ -0,0 +1,25 @@
+package com.baeldung.algorithms.insertionsort;
+
+import com.baeldung.algorithms.insertionsort.InsertionSort;
+import org.junit.Test;
+
+import static org.junit.Assert.assertArrayEquals;
+
+public class InsertionSortUnitTest {
+
+    @Test
+    public void givenUnsortedArray_whenInsertionSortImperative_thenSortedAsc() {
+        int[] input = {6, 2, 3, 4, 5, 1};
+        InsertionSort.insertionSortImperative(input);
+        int[] expected = {1, 2, 3, 4, 5, 6};
+        assertArrayEquals("the two arrays are not equal", expected, input);
+    }
+
+    @Test
+    public void givenUnsortedArray_whenInsertionSortRecursive_thenSortedAsc() {
+        int[] input = {6, 4, 5, 2, 3, 1};
+        InsertionSort.insertionSortRecursive(input);
+        int[] expected = {1, 2, 3, 4, 5, 6};
+        assertArrayEquals("the two arrays are not equal", expected, input);
+    }
+}
@@ -1,46 +0,0 @@
-package com.baeldung.internationalization;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-import java.time.LocalDateTime;
-import java.time.ZoneId;
-import java.time.ZonedDateTime;
-import java.time.format.DateTimeFormatter;
-import java.time.format.FormatStyle;
-import java.util.Locale;
-import java.util.TimeZone;
-
-public class DateTimeFormatterUnitTest {
-
-    @Test
-    public void givenDefaultUsLocaleAndDateTimeAndPattern_whenFormatWithDifferentLocales_thenGettingLocalizedDateTimes() {
-        Locale.setDefault(Locale.US);
-        LocalDateTime localDateTime = LocalDateTime.of(2018, 1, 1, 10, 15, 50, 500);
-        String pattern = "dd-MMMM-yyyy HH:mm:ss.SSS";
-
-        DateTimeFormatter defaultTimeFormatter = DateTimeFormatter.ofPattern(pattern);
-        DateTimeFormatter plTimeFormatter = DateTimeFormatter.ofPattern(pattern, new Locale("pl", "PL"));
-        DateTimeFormatter deTimeFormatter = DateTimeFormatter.ofPattern(pattern).withLocale(Locale.GERMANY);
-
-        Assert.assertEquals("01-January-2018 10:15:50.000", defaultTimeFormatter.format(localDateTime));
-        Assert.assertEquals("01-stycznia-2018 10:15:50.000", plTimeFormatter.format(localDateTime));
-        Assert.assertEquals("01-Januar-2018 10:15:50.000", deTimeFormatter.format(localDateTime));
-    }
-
-    @Test
-    public void givenDateTimeAndTimeZone_whenFormatWithDifferentLocales_thenGettingLocalizedZonedDateTimes() {
-        Locale.setDefault(Locale.US);
-        LocalDateTime localDateTime = LocalDateTime.of(2018, 1, 1, 10, 15, 50, 500);
-        ZoneId losAngelesTimeZone = TimeZone.getTimeZone("America/Los_Angeles").toZoneId();
-
-        DateTimeFormatter localizedFormatter = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.FULL);
-        DateTimeFormatter frLocalizedFormatter =
-                DateTimeFormatter.ofLocalizedDateTime(FormatStyle.FULL).withLocale(Locale.FRANCE);
-        String formattedDateTime = localizedFormatter.format(ZonedDateTime.of(localDateTime, losAngelesTimeZone));
-        String frFormattedDateTime = frLocalizedFormatter.format(ZonedDateTime.of(localDateTime, losAngelesTimeZone));
-
-        Assert.assertEquals("Monday, January 1, 2018 10:15:50 AM PST", formattedDateTime);
-        Assert.assertEquals("lundi 1 janvier 2018 10 h 15 PST", frFormattedDateTime);
-    }
-}
@@ -48,6 +48,7 @@
 - [Thread Safe LIFO Data Structure Implementations](https://www.baeldung.com/java-lifo-thread-safe)
 - [Collections.emptyList() vs. New List Instance](https://www.baeldung.com/java-collections-emptylist-new-list)
 - [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)
+- [Differences Between Collection.clear() and Collection.removeAll()](https://www.baeldung.com/java-collection-clear-vs-removeall)
 - [Performance of contains() in a HashSet vs ArrayList](https://www.baeldung.com/java-hashset-arraylist-contains-performance)
 - [Get the Key for a Value from a Java Map](https://www.baeldung.com/java-map-key-from-value)
 - [Time Complexity of Java Collections](https://www.baeldung.com/java-collections-complexity)
@@ -1,85 +1,83 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <groupId>com.baeldung</groupId>
-    <artifactId>core-java-collections</artifactId>
-    <version>0.1.0-SNAPSHOT</version>
-    <packaging>jar</packaging>
-    <name>core-java-collections</name>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-java</artifactId>
-        <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../parent-java</relativePath>
-    </parent>
-
-    <dependencies>
-        <dependency>
-            <groupId>net.sourceforge.collections</groupId>
-            <artifactId>collections-generic</artifactId>
-            <version>${collections-generic.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.commons</groupId>
-            <artifactId>commons-collections4</artifactId>
-            <version>${commons-collections4.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>com.jayway.awaitility</groupId>
-            <artifactId>awaitility</artifactId>
-            <version>${avaitility.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.commons</groupId>
-            <artifactId>commons-lang3</artifactId>
-            <version>${commons-lang3.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.eclipse.collections</groupId>
-            <artifactId>eclipse-collections</artifactId>
-            <version>${eclipse.collections.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.junit.platform</groupId>
-            <artifactId>junit-platform-runner</artifactId>
-            <version>${junit.platform.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.openjdk.jmh</groupId>
-            <artifactId>jmh-core</artifactId>
-            <version>${openjdk.jmh.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.openjdk.jmh</groupId>
-            <artifactId>jmh-generator-annprocess</artifactId>
-            <version>${openjdk.jmh.version}</version>
-        </dependency>
-		<dependency>
-		    <groupId>org.apache.commons</groupId>
-		    <artifactId>commons-exec</artifactId>
-		    <version>1.3</version>
-		</dependency>
-		        
-    </dependencies>
-
-
-    <properties>
-        <openjdk.jmh.version>1.19</openjdk.jmh.version>
-        <junit.platform.version>1.2.0</junit.platform.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
-        <commons-collections4.version>4.1</commons-collections4.version>
-        <collections-generic.version>4.01</collections-generic.version>
-        <avaitility.version>1.7.0</avaitility.version>
-        <assertj.version>3.6.1</assertj.version>
-        <eclipse.collections.version>7.1.0</eclipse.collections.version>
-    </properties>
-</project>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>core-java-collections</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <name>core-java-collections</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>net.sourceforge.collections</groupId>
+            <artifactId>collections-generic</artifactId>
+            <version>${collections-generic.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.jayway.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>${avaitility.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.eclipse.collections</groupId>
+            <artifactId>eclipse-collections</artifactId>
+            <version>${eclipse.collections.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit.platform.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${openjdk.jmh.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${openjdk.jmh.version}</version>
+        </dependency>
+	    <dependency>
+		<groupId>org.apache.commons</groupId>
+		<artifactId>commons-exec</artifactId>
+		<version>1.3</version>
+        </dependency>	        
+    </dependencies>
+
+    <properties>
+        <openjdk.jmh.version>1.19</openjdk.jmh.version>
+        <junit.platform.version>1.2.0</junit.platform.version>
+        <commons-lang3.version>3.5</commons-lang3.version>
+        <commons-collections4.version>4.1</commons-collections4.version>
+        <collections-generic.version>4.01</collections-generic.version>
+        <avaitility.version>1.7.0</avaitility.version>
+        <assertj.version>3.6.1</assertj.version>
+        <eclipse.collections.version>7.1.0</eclipse.collections.version>
+    </properties>
+</project>
@@ -0,0 +1,52 @@
+package com.baeldung.convertcollectiontoarraylist;
+
+/**
+ * This POJO is the element type of our collection. It has a deepCopy() method.
+ *
+ * @author chris
+ */
+public class Foo {
+
+    private int id;
+    private String name;
+    private Foo parent;
+
+    public Foo() {
+    }
+
+    public Foo(int id, String name, Foo parent) {
+        this.id = id;
+        this.name = name;
+        this.parent = parent;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Foo getParent() {
+        return parent;
+    }
+
+    public void setParent(Foo parent) {
+        this.parent = parent;
+    }
+
+    public Foo deepCopy() {
+        return new Foo(
+          this.id, this.name, this.parent != null ? this.parent.deepCopy() : null);
+    }
+
+}
@@ -0,0 +1,105 @@
+package com.baeldung.map.java_8;
+
+import com.baeldung.sort.Employee;
+import one.util.streamex.EntryStream;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class MergeMaps {
+
+    private static Map<String, Employee> map1 = new HashMap<>();
+    private static Map<String, Employee> map2 = new HashMap<>();
+
+    public static void main(String[] args) {
+
+        initialize();
+
+        mergeFunction();
+
+        streamConcat();
+
+        streamOf();
+
+        streamEx();
+
+        streamMerge();
+    }
+
+    private static void streamMerge() {
+
+        Map<String, Employee> map3 = map2.entrySet()
+                .stream()
+                .collect(
+                        Collectors.toMap(
+                                Map.Entry::getKey,
+                                Map.Entry::getValue,
+                                (v1, v2) -> new Employee(v1.getId(), v2.getName()),
+                                () -> new HashMap<>(map1)
+                        )
+                );
+
+        System.out.println(map3);
+    }
+
+    private static void streamEx() {
+        Map<String, Employee> map3 = EntryStream.of(map1)
+                .append(EntryStream.of(map2))
+                .toMap((e1, e2) -> e1);
+
+        System.out.println(map3);
+
+    }
+
+    private static void streamOf() {
+        Map<String, Employee> map3 = Stream.of(map1, map2)
+                .flatMap(map -> map.entrySet().stream())
+                .collect(
+                        Collectors.toMap(
+                                Map.Entry::getKey,
+                                Map.Entry::getValue,
+                                (v1, v2) -> new Employee(v1.getId(), v2.getName())
+                        )
+                );
+
+        map3.entrySet().forEach(System.out::println);
+    }
+
+    private static void streamConcat() {
+        Map<String, Employee> result = Stream.concat(map1.entrySet().stream(), map2.entrySet().stream()).collect(Collectors.toMap(
+                Map.Entry::getKey,
+                Map.Entry::getValue,
+                (value1, value2) -> new Employee(value2.getId(), value1.getName())
+        ));
+
+        result.entrySet().forEach(System.out::println);
+    }
+
+    private static void mergeFunction() {
+        Map<String, Employee> map3 = new HashMap<>(map1);
+
+        map2.forEach(
+                (key, value) -> map3.merge(key, value, (v1, v2) ->
+                        new Employee(v1.getId(), v2.getName()))
+        );
+
+        map3.entrySet().forEach(System.out::println);
+    }
+
+
+    private static void initialize() {
+        Employee employee1 = new Employee(1L, "Henry");
+        map1.put(employee1.getName(), employee1);
+        Employee employee2 = new Employee(22L, "Annie");
+        map1.put(employee2.getName(), employee2);
+        Employee employee3 = new Employee(8L, "John");
+        map1.put(employee3.getName(), employee3);
+
+        Employee employee4 = new Employee(2L, "George");
+        map2.put(employee4.getName(), employee4);
+        Employee employee5 = new Employee(3L, "Henry");
+        map2.put(employee5.getName(), employee5);
+    }
+
+}
@@ -0,0 +1,18 @@
+package com.baeldung.synchronizedcollections.application;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.logging.Logger;
+
+public class Application {
+
+    private static final Logger LOGGER = Logger.getLogger(Application.class.getName());
+    
+    public static void main(String[] args) throws InterruptedException {
+        List<Integer> syncCollection = Collections.synchronizedList(Arrays.asList(1, 2, 3, 4, 5, 6));
+        synchronized (syncCollection) {
+            syncCollection.forEach((e) -> {LOGGER.info(e.toString());});
+        }
+    }
+}
@@ -0,0 +1,148 @@
+package com.baeldung.convertcollectiontoarraylist;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.Iterator;
+import static java.util.stream.Collectors.toCollection;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+/**
+ *
+ * @author chris
+ */
+public class FooUnitTest {
+    private static Collection<Foo> srcCollection = new HashSet<>();
+
+    public FooUnitTest() {
+    }
+    
+    @BeforeClass
+    public static void setUpClass() {
+        int i = 0;
+        Foo john = new Foo(i++, "John", null);
+        Foo mary = new Foo(i++, "Mary", null);
+        Foo sam = new Foo(i++, "Sam", john);
+        Foo alice = new Foo(i++, "Alice", john);
+        Foo buffy = new Foo(i++, "Buffy", sam);
+        srcCollection.add(john);
+        srcCollection.add(mary);
+        srcCollection.add(sam);
+        srcCollection.add(alice);
+        srcCollection.add(buffy);
+
+        // make sure the collection isn't sorted accidentally
+        assertFalse("Oops: source collection is already sorted!", isSorted(srcCollection));
+    }
+    
+    /**
+     * Section 3. Using the ArrayList Constructor
+     */
+    @Test
+    public void whenUsingConstructor_thenVerifyShallowCopy() {
+        ArrayList<Foo> newList = new ArrayList<>(srcCollection);
+        verifyShallowCopy(srcCollection, newList);
+    }
+    
+    /**
+     * Section 4. Using the Streams API
+     */
+    @Test
+    public void whenUsingStream_thenVerifyShallowCopy() {
+        ArrayList<Foo> newList = srcCollection.stream().collect(toCollection(ArrayList::new));
+
+        verifyShallowCopy(srcCollection, newList);
+    }
+    
+    /**
+     * Section 5. Deep Copy
+     */
+    @Test
+    public void whenUsingDeepCopy_thenVerifyDeepCopy() {
+        ArrayList<Foo> newList = srcCollection.stream()
+          .map(foo -> foo.deepCopy())
+          .collect(toCollection(ArrayList::new));
+
+        verifyDeepCopy(srcCollection, newList);
+    }
+    
+    /**
+     * Section 6. Controlling the List Order
+     */
+    @Test
+    public void whenUsingSortedStream_thenVerifySortOrder() {
+        ArrayList<Foo> newList = srcCollection.stream()
+          .sorted(Comparator.comparing(Foo::getName))
+          .collect(toCollection(ArrayList::new));
+
+        assertTrue("ArrayList is not sorted by name", isSorted(newList));
+    }
+    
+    /**
+     * Verify that the contents of the two collections are the same
+     * @param a
+     * @param b 
+     */
+    private void verifyShallowCopy(Collection a, Collection b) {
+        assertEquals("Collections have different lengths", a.size(), b.size());
+        Iterator<Foo> iterA = a.iterator();
+        Iterator<Foo> iterB = b.iterator();
+        while (iterA.hasNext()) {
+            // use '==' to test instance identity
+            assertTrue("Foo instances differ!", iterA.next() == iterB.next());
+        }
+    }
+    
+    /**
+     * Verify that the contents of the two collections are the same
+     * @param a
+     * @param b 
+     */
+    private void verifyDeepCopy(Collection a, Collection b) {
+        assertEquals("Collections have different lengths", a.size(), b.size());
+        Iterator<Foo> iterA = a.iterator();
+        Iterator<Foo> iterB = b.iterator();
+        while (iterA.hasNext()) {
+            Foo nextA = iterA.next();
+            Foo nextB = iterB.next();
+            // should not be same instance
+            assertFalse("Foo instances are the same!", nextA == nextB);
+            // but should have same content
+            assertFalse("Foo instances have different content!", fooDiff(nextA, nextB));
+        }
+    }
+
+    /**
+     * Return true if the contents of a and b differ.  Test parent recursively
+     * @param a
+     * @param b
+     * @return False if the two items are the same
+     */
+    private boolean fooDiff(Foo a, Foo b) {
+        if (a != null && b != null) {
+            return a.getId() != b.getId() 
+              || !a.getName().equals(b.getName()) 
+              || fooDiff(a.getParent(), b.getParent());
+        }
+        return !(a == null && b == null);
+    }
+    
+    /**
+     * @param c collection of Foo
+     * @return true if the collection is sorted by name
+     */
+    private static boolean isSorted(Collection<Foo> c) {
+        String prevName = null;
+        for (Foo foo : c) {
+            if (prevName == null || foo.getName().compareTo(prevName) > 0) {
+                prevName = foo.getName();
+            } else {
+                return false;
+            }
+        }
+        return true;
+    }
+}
@@ -0,0 +1,29 @@
+package com.baeldung.java.map;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Collections;
+import java.util.Map;
+
+import org.junit.Test;
+
+public class KeyCheckUnitTest {
+
+    @Test
+    public void whenKeyIsPresent_thenContainsKeyReturnsTrue() {
+        Map<String, String> map = Collections.singletonMap("key", "value");
+
+        assertTrue(map.containsKey("key"));
+        assertFalse(map.containsKey("missing"));
+    }
+
+    @Test
+    public void whenKeyHasNullValue_thenGetStillWorks() {
+        Map<String, String> map = Collections.singletonMap("nothing", null);
+
+        assertTrue(map.containsKey("nothing"));
+        assertNull(map.get("nothing"));
+    }
+}
@@ -0,0 +1,28 @@
+package com.baeldung.synchronizedcollections.test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
+
+public class SynchronizedCollectionUnitTest {
+
+    @Test
+    public void givenSynchronizedCollection_whenTwoThreadsAddElements_thenCorrectCollectionSize() throws InterruptedException {
+        Collection<Integer> syncCollection = Collections.synchronizedCollection(new ArrayList<>());
+
+        Runnable listOperations = () -> {
+            syncCollection.addAll(Arrays.asList(1, 2, 3, 4, 5, 6));
+        };
+        Thread thread1 = new Thread(listOperations);
+        Thread thread2 = new Thread(listOperations);
+        thread1.start();
+        thread2.start();
+        thread1.join();
+        thread2.join();
+
+        assertThat(syncCollection.size()).isEqualTo(12);
+    }
+}
@@ -0,0 +1,51 @@
+package com.baeldung.synchronizedcollections.test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import org.junit.Test;
+import static org.assertj.core.api.Assertions.*;
+
+public class SynchronizedListUnitTest {
+
+    @Test
+    public void givenSynchronizedList_whenTwoThreadsAddElements_thenCorrectListSize() throws InterruptedException {
+        List<Integer> syncList = Collections.synchronizedList(new ArrayList<>());
+
+        Runnable listOperations = () -> {
+            syncList.addAll(Arrays.asList(1, 2, 3, 4, 5, 6));
+        };
+        Thread thread1 = new Thread(listOperations);
+        Thread thread2 = new Thread(listOperations);
+        thread1.start();
+        thread2.start();
+        thread1.join();
+        thread2.join();
+        
+        assertThat(syncList.size()).isEqualTo(12);
+    }
+    
+    @Test
+    public void givenStringList_whenTwoThreadsIterateOnSynchronizedList_thenCorrectResult() throws InterruptedException {
+        List<String> syncCollection = Collections.synchronizedList(Arrays.asList("a", "b", "c"));
+        List<String> uppercasedCollection = new ArrayList<>();
+
+        Runnable listOperations = () -> {
+            synchronized (syncCollection) {
+                syncCollection.forEach((e) -> {
+                    uppercasedCollection.add(e.toUpperCase());
+                });
+            }
+        };
+        
+        Thread thread1 = new Thread(listOperations);
+        Thread thread2 = new Thread(listOperations);
+        thread1.start();
+        thread2.start();
+        thread1.join();
+        thread2.join();
+        
+        assertThat(uppercasedCollection.get(0)).isEqualTo("A");
+    }
+}
@@ -0,0 +1,30 @@
+package com.baeldung.synchronizedcollections.test;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import org.junit.Test;
+import static org.assertj.core.api.Assertions.*;
+
+public class SynchronizedMapUnitTest {
+
+    @Test
+    public void givenSynchronizedMap_whenTwoThreadsAddElements_thenCorrectMapSize() throws InterruptedException {
+        Map<Integer, String> syncMap = Collections.synchronizedMap(new HashMap<>());
+
+        Runnable mapOperations = () -> {
+            syncMap.put(1, "one");
+            syncMap.put(2, "two");
+            syncMap.put(3, "three");
+            
+        };
+        Thread thread1 = new Thread(mapOperations);
+        Thread thread2 = new Thread(mapOperations);
+        thread1.start();
+        thread2.start();
+        thread1.join();
+        thread2.join();
+        
+        assertThat(syncMap.size()).isEqualTo(3);
+    }
+}
@@ -0,0 +1,26 @@
+package com.baeldung.synchronizedcollections.test;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import org.junit.Test;
+import static org.assertj.core.api.Assertions.*;
+
+public class SynchronizedSetUnitTest {
+    
+    @Test
+    public void givenSynchronizedSet_whenTwoThreadsAddElements_thenCorrectSetSize() throws InterruptedException {
+        Set<Integer> syncSet = Collections.synchronizedSet(new HashSet<>());
+        
+        Runnable setOperations = () -> {syncSet.addAll(Arrays.asList(1, 2, 3, 4, 5, 6));};
+        Thread thread1 = new Thread(setOperations);
+        Thread thread2 = new Thread(setOperations);
+        thread1.start();
+        thread2.start();
+        thread1.join();
+        thread2.join();
+        
+        assertThat(syncSet.size()).isEqualTo(6);
+    }
+}
@@ -0,0 +1,29 @@
+package com.baeldung.synchronizedcollections.test;
+
+import java.util.Collections;
+import java.util.Map;
+import java.util.TreeMap;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
+
+public class SynchronizedSortedMapUnitTest {
+    
+    @Test
+    public void givenSynchronizedSorteMap_whenTwoThreadsAddElements_thenCorrectSortedMapSize() throws InterruptedException {
+        Map<Integer, String> syncSortedMap = Collections.synchronizedSortedMap(new TreeMap<>());
+        
+        Runnable sortedMapOperations = () -> {
+            syncSortedMap.put(1, "One");
+            syncSortedMap.put(2, "Two");
+            syncSortedMap.put(3, "Three");
+        };
+        Thread thread1 = new Thread(sortedMapOperations);
+        Thread thread2 = new Thread(sortedMapOperations);
+        thread1.start();
+        thread2.start();
+        thread1.join();
+        thread2.join();
+        
+        assertThat(syncSortedMap.size()).isEqualTo(3);
+    }
+}
@@ -0,0 +1,28 @@
+package com.baeldung.synchronizedcollections.test;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.SortedSet;
+import java.util.TreeSet;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
+
+public class SynchronizedSortedSetUnitTest {
+    
+    @Test
+    public void givenSynchronizedSortedSet_whenTwoThreadsAddElements_thenCorrectSortedSetSize() throws InterruptedException {
+        SortedSet<Integer> syncSortedSet = Collections.synchronizedSortedSet(new TreeSet<>());
+        
+        Runnable sortedSetOperations = () -> {syncSortedSet.addAll(Arrays.asList(1, 2, 3, 4, 5, 6));};
+        sortedSetOperations.run();
+        sortedSetOperations.run();
+        Thread thread1 = new Thread(sortedSetOperations);
+        Thread thread2 = new Thread(sortedSetOperations);
+        thread1.start();
+        thread2.start();
+        thread1.join();
+        thread2.join();
+        
+        assertThat(syncSortedSet.size()).isEqualTo(6);
+    }
+}
@@ -0,0 +1,48 @@
+package com.baeldung.stream;
+
+import java.io.BufferedOutputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+
+public class OutputStreamExamples {
+
+    public void fileOutputStreamByteSequence(String file, String data) throws IOException {
+        byte[] bytes = data.getBytes();
+        try (OutputStream out = new FileOutputStream(file)) {
+            out.write(bytes);
+        }
+    }
+
+    public void fileOutputStreamByteSubSequence(String file, String data) throws IOException {
+        byte[] bytes = data.getBytes();
+        try (OutputStream out = new FileOutputStream(file)) {
+            out.write(bytes, 6, 5);
+        }
+    }
+
+    public void fileOutputStreamByteSingle(String file, String data) throws IOException {
+        byte[] bytes = data.getBytes();
+        try (OutputStream out = new FileOutputStream(file)) {
+            out.write(bytes[6]);
+        }
+    }
+
+    public void bufferedOutputStream(String file, String... data) throws IOException {
+        try (BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(file))) {
+            for (String s : data) {
+                out.write(s.getBytes());
+                out.write(" ".getBytes());
+            }
+        }
+    }
+
+    public void outputStreamWriter(String file, String data) throws IOException {
+        try (OutputStream out = new FileOutputStream(file); Writer writer = new OutputStreamWriter(out, "UTF-8")) {
+            writer.write(data);
+        }
+    }
+
+}
@@ -0,0 +1,76 @@
+package com.baeldung.stream;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class OutputStreamExamplesTest {
+    
+    StringBuilder filePath = new StringBuilder();
+    
+    @Before
+    public void init() {
+        filePath.append("src");
+        filePath.append(File.separator);
+        filePath.append("test");
+        filePath.append(File.separator);
+        filePath.append("resources");
+        filePath.append(File.separator);
+        filePath.append("output_file.txt");
+    }
+    
+    @Test
+    public void givenOutputStream_whenWriteSingleByteCalled_thenOutputCreated() throws IOException {
+        
+        final File file = new File(filePath.toString());    
+        OutputStreamExamples examples = new OutputStreamExamples();    
+        examples.fileOutputStreamByteSingle(filePath.toString(), "Hello World!");
+        assertTrue(file.exists());
+        file.delete();
+    }
+    
+    @Test
+    public void givenOutputStream_whenWriteByteSequenceCalled_thenOutputCreated() throws IOException {
+        
+        final File file = new File(filePath.toString());    
+        OutputStreamExamples examples = new OutputStreamExamples();    
+        examples.fileOutputStreamByteSequence(filePath.toString(), "Hello World!");
+        assertTrue(file.exists());
+        file.delete();
+    }
+    
+    @Test
+    public void givenOutputStream_whenWriteByteSubSequenceCalled_thenOutputCreated() throws IOException {
+        
+        final File file = new File(filePath.toString());    
+        OutputStreamExamples examples = new OutputStreamExamples();    
+        examples.fileOutputStreamByteSubSequence(filePath.toString(), "Hello World!");
+        assertTrue(file.exists());
+        file.delete();
+    }
+
+    @Test
+    public void givenBufferedOutputStream_whenCalled_thenOutputCreated() throws IOException {
+        
+        final File file = new File(filePath.toString());    
+        OutputStreamExamples examples = new OutputStreamExamples();    
+        examples.bufferedOutputStream(filePath.toString(), "Hello", "World!");
+        assertTrue(file.exists());
+        file.delete();
+    }
+    
+    @Test
+    public void givenOutputStreamWriter_whenCalled_thenOutputCreated() throws IOException {
+        
+        final File file = new File(filePath.toString());    
+        OutputStreamExamples examples = new OutputStreamExamples();    
+        examples.outputStreamWriter(filePath.toString(), "Hello World!");
+        assertTrue(file.exists());
+        file.delete();
+    }
+
+}
@@ -25,7 +25,6 @@
 - [The Traveling Salesman Problem in Java](http://www.baeldung.com/java-simulated-annealing-for-traveling-salesman)
 - [How to Create an Executable JAR with Maven](http://www.baeldung.com/executable-jar-with-maven)
 - [How to Design a Genetic Algorithm in Java](http://www.baeldung.com/java-genetic-algorithm)
- [Spring Security – Cache Control Headers](http://www.baeldung.com/spring-security-cache-control-headers)
 - [Basic Introduction to JMX](http://www.baeldung.com/java-management-extensions)
 - [AWS Lambda With Java](http://www.baeldung.com/java-aws-lambda)
 - [Introduction to Nashorn](http://www.baeldung.com/java-nashorn)
@@ -37,7 +36,6 @@
 - [Guide to sun.misc.Unsafe](http://www.baeldung.com/java-unsafe)
 - [How to Perform a Simple HTTP Request in Java](http://www.baeldung.com/java-http-request)
 - [Call Methods at Runtime Using Java Reflection](http://www.baeldung.com/java-method-reflection)
- [Guide to UUID in JAVA](http://www.baeldung.com/guide-to-uuid-in-java)
 - [How to Add a Single Element to a Stream](http://www.baeldung.com/java-stream-append-prepend)
 - [Iterating Over Enum Values in Java](http://www.baeldung.com/java-enum-iteration)
 - [Kotlin Java Interoperability](http://www.baeldung.com/kotlin-java-interoperability)
@@ -1,11 +1,14 @@
 package com.baeldung.classloader;

-import java.io.*;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;

 public class CustomClassLoader extends ClassLoader {

-
-    public Class getClass(String name) throws ClassNotFoundException {
+    @Override
+    public Class findClass(String name) throws ClassNotFoundException {
        byte[] b = loadClassFromFile(name);
        return defineClass(name, b, 0, b.length);
    }
@@ -11,7 +11,7 @@ public class CustomClassLoaderUnitTest {
    public void customLoader() throws ClassNotFoundException, IllegalAccessException, InstantiationException, NoSuchMethodException, InvocationTargetException {

        CustomClassLoader customClassLoader = new CustomClassLoader();
-        Class<?> c = customClassLoader.getClass(PrintClassLoader.class.getName());
+        Class<?> c = customClassLoader.findClass(PrintClassLoader.class.getName());

        Object ob = c.newInstance();

@@ -0,0 +1,3 @@
+### Relevant articles
+
+- [CDI Portable Extension and Flyway](https://www.baeldung.com/cdi-portable-extension)
@@ -14,4 +14,5 @@
 - [Bootstrapping JPA Programmatically in Java](http://www.baeldung.com/java-bootstrap-jpa)
 - [Optimistic Locking in JPA](http://www.baeldung.com/jpa-optimistic-locking)
 - [Hibernate Entity Lifecycle](https://www.baeldung.com/hibernate-entity-lifecycle)
+- [Mapping A Hibernate Query to a Custom Class](https://www.baeldung.com/hibernate-query-to-custom-class)
 - [@JoinColumn Annotation Explained](https://www.baeldung.com/jpa-join-column)
@@ -0,0 +1,47 @@
+package com.baeldung.hibernate.namingstrategy;
+
+import org.hibernate.boot.model.naming.Identifier;
+import org.hibernate.boot.model.naming.PhysicalNamingStrategy;
+import org.hibernate.engine.jdbc.env.spi.JdbcEnvironment;
+
+public class CustomPhysicalNamingStrategy implements PhysicalNamingStrategy {
+
+    @Override
+    public Identifier toPhysicalCatalogName(final Identifier identifier, final JdbcEnvironment jdbcEnv) {
+        return convertToSnakeCase(identifier);
+    }
+
+    @Override
+    public Identifier toPhysicalColumnName(final Identifier identifier, final JdbcEnvironment jdbcEnv) {
+        return convertToSnakeCase(identifier);
+    }
+
+    @Override
+    public Identifier toPhysicalSchemaName(final Identifier identifier, final JdbcEnvironment jdbcEnv) {
+        return convertToSnakeCase(identifier);
+    }
+
+    @Override
+    public Identifier toPhysicalSequenceName(final Identifier identifier, final JdbcEnvironment jdbcEnv) {
+        return convertToSnakeCase(identifier);
+    }
+
+    @Override
+    public Identifier toPhysicalTableName(final Identifier identifier, final JdbcEnvironment jdbcEnv) {
+        return convertToSnakeCase(identifier);
+    }
+
+    private Identifier convertToSnakeCase(final Identifier identifier) {
+        if (identifier == null) {
+            return identifier;
+        }
+
+        final String regex = "([a-z])([A-Z])";
+        final String replacement = "$1_$2";
+        final String newName = identifier.getText()
+            .replaceAll(regex, replacement)
+            .toLowerCase();
+        return Identifier.toIdentifier(newName);
+    }
+
+}
@@ -0,0 +1,56 @@
+package com.baeldung.hibernate.namingstrategy;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "Customers")
+public class Customer {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    private String firstName;
+
+    private String lastName;
+
+    @Column(name = "email")
+    private String emailAddress;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public String getEmailAddress() {
+        return emailAddress;
+    }
+
+    public void setEmailAddress(String emailAddress) {
+        this.emailAddress = emailAddress;
+    }
+
+}
@@ -4,13 +4,23 @@ import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.GenerationType;
 import javax.persistence.Id;
-import javax.persistence.SequenceGenerator;
+
+import org.hibernate.annotations.GenericGenerator;
+import org.hibernate.annotations.Parameter;

@Entity
 public class User {
    @Id
-    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequence-generator")
-    @SequenceGenerator(name = "sequence-generator", sequenceName = "user_sequence", initialValue = 4)
+    @GeneratedValue(generator = "sequence-generator")
+    @GenericGenerator(
+        name = "sequence-generator",
+        strategy = "org.hibernate.id.enhanced.SequenceStyleGenerator",
+        parameters = {
+                @Parameter(name = "sequence_name", value = "user_sequence"),
+                @Parameter(name = "initial_value", value = "4"),
+                @Parameter(name = "increment_size", value = "1")
+        }
+    )
    private long userId;

    public long getUserId() {
@@ -0,0 +1,75 @@
+package com.baeldung.hibernate.namingstrategy;
+
+import static org.junit.Assert.fail;
+
+import java.io.IOException;
+import java.util.Properties;
+
+import org.hibernate.HibernateException;
+import org.hibernate.Session;
+import org.hibernate.SessionFactory;
+import org.hibernate.boot.MetadataSources;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.cfg.Configuration;
+import org.hibernate.service.ServiceRegistry;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class NamingStrategyLiveTest {
+
+    private Session session;
+
+    @Before
+    public void init() {
+        try {
+            Configuration configuration = new Configuration();
+
+            Properties properties = new Properties();
+            properties.load(Thread.currentThread()
+                .getContextClassLoader()
+                .getResourceAsStream("hibernate-namingstrategy.properties"));
+
+            configuration.setProperties(properties);
+
+            ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties())
+                .build();
+            MetadataSources metadataSources = new MetadataSources(serviceRegistry);
+            metadataSources.addAnnotatedClass(Customer.class);
+
+            SessionFactory factory = metadataSources.buildMetadata()
+                .buildSessionFactory();
+
+            session = factory.openSession();
+        } catch (HibernateException | IOException e) {
+            fail("Failed to initiate Hibernate Session [Exception:" + e.toString() + "]");
+        }
+    }
+
+    @After
+    public void close() {
+        if (session != null)
+            session.close();
+    }
+
+    @Test
+    public void testCustomPhysicalNamingStrategy() {
+
+        Customer customer = new Customer();
+        customer.setFirstName("first name");
+        customer.setLastName("last name");
+        customer.setEmailAddress("[email protected]");
+
+        session.beginTransaction();
+
+        Long id = (Long) session.save(customer);
+
+        session.flush();
+        session.clear();
+
+        Object[] result = (Object[]) session.createNativeQuery("select c.first_name, c.last_name, c.email from customers c where c.id = :id")
+            .setParameter("id", id)
+            .getSingleResult();
+
+    }
+}
@@ -0,0 +1,10 @@
+hibernate.connection.driver_class=org.h2.Driver
+hibernate.connection.url=jdbc:h2:mem:mydb1;DB_CLOSE_DELAY=-1
+hibernate.connection.username=sa
+hibernate.dialect=org.hibernate.dialect.H2Dialect
+
+hibernate.show_sql=true
+hibernate.hbm2ddl.auto=create-drop
+
+hibernate.physical_naming_strategy=com.baeldung.hibernate.namingstrategy.CustomPhysicalNamingStrategy
+hibernate.implicit_naming_strategy=org.hibernate.boot.model.naming.ImplicitNamingStrategyJpaCompliantImpl
--- a/Show More
+++ b/Show More