Merge branch 'master' into thombergs-patch-27

Twitter4J/pom.xml

@@ -1,13 +1,9 @@
 <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/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>
-
-    <groupId>com.mabsisa</groupId>
     <artifactId>Twitter4J</artifactId>
     <packaging>jar</packaging>
-    <version>1.0-SNAPSHOT</version>
     <name>Twitter4J</name>
-    <url>http://maven.apache.org</url>
 
     <parent>
         <groupId>com.baeldung</groupId>
@@ -23,27 +19,6 @@
         </dependency>
     </dependencies>
 
-    <build>
-        <finalName>${project.artifactId}</finalName>
-        <resources>
-            <resource>
-                <directory>src/main/resources</directory>
-            </resource>
-        </resources>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <version>${maven-surefire-plugin.version}</version>
-                <configuration>
-                    <excludes>
-                        <exclude>**/ApplicationTest.java</exclude>
-                    </excludes>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
-
     <properties>
         <twitter4j-stream.version>4.0.6</twitter4j-stream.version>
     </properties>

activejdbc/pom.xml

@@ -1,7 +1,6 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-    <groupId>com.baeldung</groupId>
     <artifactId>activejdbc</artifactId>
     <version>1.0-SNAPSHOT</version>
     <packaging>jar</packaging>
@@ -79,55 +78,11 @@
                     </dependency>
                 </dependencies>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <version>${maven-surefire-plugin.version}</version>
-                <configuration>
-                    <reportFormat>brief</reportFormat>
-                    <trimStackTrace>true</trimStackTrace>
-                    <useFile>false</useFile>
-                    <includes>
-                        <include>**/*Spec*.java</include>
-                        <include>**/*Test*.java</include>
-                    </includes>
-                    <excludes>
-                        <exclude>**/helpers/*</exclude>
-                        <exclude>**/*$*</exclude>
-                    </excludes>
-                </configuration>
-            </plugin>
         </plugins>
     </build>
 
-    <repositories>
-        <repository>
-            <id>snapshots1</id>
-            <name>JavaLite Snapshots1</name>
-            <url>http://repo.javalite.io/</url>
-            <snapshots>
-                <enabled>true</enabled>
-                <updatePolicy>always</updatePolicy>
-                <checksumPolicy>warn</checksumPolicy>
-            </snapshots>
-        </repository>
-    </repositories>
-
-    <pluginRepositories>
-        <pluginRepository>
-            <id>snapshots2</id>
-            <name>JavaLite Snapshots2</name>
-            <url>http://repo.javalite.io/</url>
-            <snapshots>
-                <enabled>true</enabled>
-                <updatePolicy>always</updatePolicy>
-                <checksumPolicy>warn</checksumPolicy>
-            </snapshots>
-        </pluginRepository>
-    </pluginRepositories>
-
     <properties>
-        <activejdbc.version>1.4.13</activejdbc.version>
+        <activejdbc.version>2.0</activejdbc.version>
         <environments>development.test,development</environments>
         <mysql.connector.version>5.1.34</mysql.connector.version>
     </properties>

activejdbc/src/main/java/com/baeldung/model/Employee.java

@@ -16,4 +16,8 @@ public class Employee extends Model {
         set("created_by",createdBy);
     }
 
+    public String getLastName() {
+        return getString("last_name");
+    }
+
 }

activejdbc/src/main/java/com/baeldung/model/Role.java

@@ -15,4 +15,8 @@ public class Role extends Model {
         set("role_name",role);
         set("created_by",createdBy);
     }
+
+    public String getRoleName() {
+        return getString("role_name");
+    }
 }

activejdbc/src/test/java/com/baeldung/ActiveJDBCAppManualTest.java

@@ -7,7 +7,7 @@ import org.junit.Test;
 
 import java.util.List;
 
-public class ActiveJDBCAppTest extends DBSpec
+public class ActiveJDBCAppManualTest extends DBSpec
 {
     @Test
     public void ifEmployeeCreated_thenIsValid() {

algorithms/README.md

@@ -24,3 +24,7 @@
 - [Practical Java Examples of the Big O Notation](http://www.baeldung.com/java-algorithm-complexity)
 - [Find the Middle Element of a Linked List](http://www.baeldung.com/java-linked-list-middle-element)
 - [An Introduction to the Theory of Big-O Notation](http://www.baeldung.com/big-o-notation)
+- [Check If Two Rectangles Overlap In Java](https://www.baeldung.com/java-check-if-two-rectangles-overlap)
+- [Calculate the Distance Between Two Points in Java](https://www.baeldung.com/java-distance-between-two-points)
+- [Find the Intersection of Two Lines in Java](https://www.baeldung.com/java-intersection-of-two-lines)
+- [Check If a String Contains All The Letters of The Alphabet](https://www.baeldung.com/java-string-contains-all-letters)

algorithms/roundUpToHundred/.gitignore

@@ -0,0 +1 @@
+/bin/

algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundred.java

@@ -0,0 +1,20 @@
+package com.java.src;
+
+import java.util.Scanner;
+
+public class RoundUpToHundred {
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        double input = scanner.nextDouble();
+        scanner.close();
+
+        RoundUpToHundred.round(input);
+    }
+
+    static long round(double input) {
+        long i = (long) Math.ceil(input);
+        return ((i + 99) / 100) * 100;
+    };
+
+}

algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundredTest.java

@@ -0,0 +1,14 @@
+package com.java.src;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class RoundUpToHundredTest {
+    @Test
+    public void givenInput_whenRound_thenRoundUpToTheNearestHundred() {
+        assertEquals("Rounded up to hundred", 100, RoundUpToHundred.round(99));
+        assertEquals("Rounded up to three hundred ", 300, RoundUpToHundred.round(200.2));
+        assertEquals("Returns same rounded value", 400, RoundUpToHundred.round(400));
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/mergesort/MergeSort.java

@@ -0,0 +1,50 @@
+package com.baeldung.algorithms.mergesort;
+
+public class MergeSort {
+
+    public static void main(String[] args) {
+        int[] a = { 5, 1, 6, 2, 3, 4 };
+        mergeSort(a, a.length);
+        for (int i = 0; i < a.length; i++)
+            System.out.println(a[i]);
+    }
+
+    public static void mergeSort(int[] a, int n) {
+        if (n < 2)
+            return;
+        int mid = n / 2;
+        int[] l = new int[mid];
+        int[] r = new int[n - mid];
+
+        for (int i = 0; i < mid; i++) {
+            l[i] = a[i];
+        }
+        for (int i = mid; i < n; i++) {
+            r[i - mid] = a[i];
+        }
+        mergeSort(l, mid);
+        mergeSort(r, n - mid);
+
+        merge(a, l, r, mid, n - mid);
+    }
+
+    public static void merge(int[] a, int[] l, int[] r, int left, int right) {
+
+        int i = 0, j = 0, k = 0;
+
+        while (i < left && j < right) {
+
+            if (l[i] < r[j])
+                a[k++] = l[i++];
+            else
+                a[k++] = r[j++];
+
+        }
+
+        while (i < left)
+            a[k++] = l[i++];
+
+        while (j < right)
+            a[k++] = r[j++];
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/quicksort/QuickSort.java

@@ -0,0 +1,39 @@
+package com.baeldung.algorithms.quicksort;
+
+public class QuickSort {
+
+    public static void quickSort(int arr[], int begin, int end)
+    {
+        if (begin < end) {
+            int partitionIndex = partition(arr, begin, end);
+
+            // Recursively sort elements of the 2 sub-arrays
+            quickSort(arr, begin, partitionIndex-1);
+            quickSort(arr, partitionIndex+1, end);
+        }
+    }
+
+    private static int partition(int arr[], int begin, int end)
+    {
+        int pivot = arr[end];
+        int i = (begin-1);
+
+        for (int j=begin; j<end; j++)
+        {
+            if (arr[j] <= pivot) {
+                i++;
+
+                int swapTemp = arr[i];
+                arr[i] = arr[j];
+                arr[j] = swapTemp;
+            }
+        }
+
+        int swapTemp = arr[i+1];
+        arr[i+1] = arr[end];
+        arr[end] = swapTemp;
+
+        return i+1;
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/quicksort/ThreeWayQuickSort.java

@@ -0,0 +1,38 @@
+package com.baeldung.algorithms.quicksort;
+
+public class ThreeWayQuickSort {
+
+    public static void threeWayQuickSort(int[] a, int begin, int end)
+    {
+        if (end <= begin) return;
+
+        // partition
+        int i = begin;
+        int less = begin;
+        int greater = end;
+
+        while (i <= greater){
+            if (a[i] < a[less]) {
+                int tmp = a[i];
+                a[i] = a[less];
+                a[less] = tmp;
+
+                i++;
+                less++;
+            }
+            else if (a[less] < a[i])	{
+                int tmp = a[i];
+                a[i] = a[greater];
+                a[greater] = tmp;
+
+                greater--;
+            }
+            else {
+                i++;
+            }
+        }
+
+        threeWayQuickSort(a, begin, less - 1);
+        threeWayQuickSort(a, greater + 1, end);
+    }
+}

algorithms/src/test/java/com/baeldung/algorithms/mergesort/MergeSortUnitTest.java

@@ -0,0 +1,17 @@
+package com.baeldung.algorithms.mergesort;
+
+import org.junit.Assert;
+
+import org.junit.Test;
+
+public class MergeSortUnitTest {
+
+    @Test
+    public void positiveTest() {
+        int[] actual = { 5, 1, 6, 2, 3, 4 };
+        int[] expected = { 1, 2, 3, 4, 5, 6 };
+        MergeSort.mergeSort(actual, actual.length);
+        Assert.assertArrayEquals(expected, actual);
+    }
+
+}

algorithms/src/test/java/com/baeldung/algorithms/quicksort/QuickSortUnitTest.java

@@ -0,0 +1,17 @@
+package com.baeldung.algorithms.quicksort;
+
+import com.baeldung.algorithms.quicksort.QuickSort;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class QuickSortUnitTest {
+
+    @Test
+    public void givenIntegerArray_whenSortedWithQuickSort_thenGetSortedArray() {
+        int[] actual = { 9, 5, 1, 0, 6, 2, 3, 4, 7, 8 };
+        int[] expected = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+        QuickSort.quickSort(actual, 0, actual.length-1);
+        Assert.assertArrayEquals(expected, actual);
+    }
+
+}

algorithms/src/test/java/com/baeldung/algorithms/quicksort/ThreeWayQuickSortUnitTest.java

@@ -0,0 +1,15 @@
+package com.baeldung.algorithms.quicksort;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ThreeWayQuickSortUnitTest {
+
+    @Test
+    public void givenIntegerArray_whenSortedWithThreeWayQuickSort_thenGetSortedArray() {
+        int[] actual = { 3, 5, 5, 5, 3, 7, 7, 3, 5, 5, 7, 3, 3 };
+        int[] expected = { 3, 3, 3, 3, 3, 5, 5, 5, 5, 5, 7, 7, 7 };
+        ThreeWayQuickSort.threeWayQuickSort(actual, 0, actual.length-1);
+        Assert.assertArrayEquals(expected, actual);
+    }
+}

animal-sniffer-mvn-plugin/src/test/java/com/baeldung/AppUnitTest.java

@@ -7,7 +7,7 @@ import junit.framework.TestSuite;
 /**
  * Unit test for simple App.
  */
-public class AppTest 
+public class AppUnitTest 
     extends TestCase
 {
     /**
@@ -15,7 +15,7 @@ public class AppTest
      *
      * @param testName name of the test case
      */
-    public AppTest( String testName )
+    public AppUnitTest( String testName )
     {
         super( testName );
     }
@@ -25,7 +25,7 @@ public class AppTest
      */
     public static Test suite()
     {
-        return new TestSuite( AppTest.class );
+        return new TestSuite( AppUnitTest.class );
     }
 
     /**

apache-avro/pom.xml

@@ -6,7 +6,7 @@
     <groupId>com.baeldung</groupId>
     <artifactId>apache-avro</artifactId>
     <version>0.0.1-SNAPSHOT</version>
-	<name>Apache Avro</version>
+	<name>Apache Avro</name>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

apache-avro/src/test/java/com/baeldung/avro/util/serealization/AvroSerealizerDeSerealizerUnitTest.java

@@ -13,7 +13,7 @@ import java.util.Objects;
 
 import static org.junit.Assert.*;
 
-public class AvroSerealizerDeSerealizerTest {
+public class AvroSerealizerDeSerealizerUnitTest {
 
     AvroSerealizer serealizer;
     AvroDeSerealizer deSerealizer;

apache-geode/pom.xml

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>apache-geode</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    
+    <properties>
+        <geode.core>1.6.0</geode.core>
+    </properties>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.geode</groupId>
+            <artifactId>geode-core</artifactId>
+            <version>${geode.core}</version>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>RELEASE</version>
+        </dependency>
+    </dependencies>
+    
+</project>

apache-geode/src/main/java/com/baeldung/geode/Customer.java

@@ -0,0 +1,78 @@
+package com.baeldung.geode;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+public class Customer implements Serializable {
+
+    private static final long serialVersionUID = -7482516011038799900L;
+
+    private CustomerKey key;
+    private String firstName;
+    private String lastName;
+    private Integer age;
+
+    public Customer() {
+    }
+
+    public Customer(String firstName, String lastName, int age) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.age = age;
+    }
+
+    public Customer(CustomerKey key, String firstName, String lastName, int age) {
+        this(firstName, lastName, age);
+        this.key = key;
+    }
+
+    // setters and getters
+
+    public static long getSerialVersionUID() {
+        return serialVersionUID;
+    }
+
+    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 Integer getAge() {
+        return age;
+    }
+
+    public void setAge(Integer age) {
+        this.age = age;
+    }
+
+    @Override
+    public String toString() {
+        return "Customer{" + "firstName='" + firstName + '\'' + ", lastName='" + lastName + '\'' + ", age=" + age + '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        Customer customer = (Customer) o;
+        return Objects.equals(firstName, customer.firstName) && Objects.equals(lastName, customer.lastName) && Objects.equals(age, customer.age);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(firstName, lastName, age);
+    }
+}

apache-geode/src/main/java/com/baeldung/geode/CustomerKey.java

@@ -0,0 +1,57 @@
+package com.baeldung.geode;
+
+import java.io.Serializable;
+
+public class CustomerKey implements Serializable {
+
+    private static final long serialVersionUID = -3529253035303792458L;
+    private long id;
+    private String country;
+
+    public CustomerKey(long id) {
+        this.id = id;
+        this.country = "USA";
+    }
+
+    public CustomerKey(long id, String country) {
+        this.id = id;
+        this.country = country;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getCountry() {
+        return country;
+    }
+
+    public void setCountry(String country) {
+        this.country = country;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+
+        CustomerKey that = (CustomerKey) o;
+
+        if (id != that.id)
+            return false;
+        return country != null ? country.equals(that.country) : that.country == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = (int) (id ^ (id >>> 32));
+        result = 31 * result + (country != null ? country.hashCode() : 0);
+        return result;
+    }
+}

apache-geode/src/main/java/com/baeldung/geode/functions/UpperCaseNames.java

@@ -0,0 +1,34 @@
+package com.baeldung.geode.functions;
+
+import com.baeldung.geode.Customer;
+import com.baeldung.geode.CustomerKey;
+import org.apache.geode.cache.Region;
+import org.apache.geode.cache.execute.Function;
+import org.apache.geode.cache.execute.FunctionContext;
+import org.apache.geode.cache.execute.RegionFunctionContext;
+
+import java.util.Map;
+
+public class UpperCaseNames implements Function<Boolean> {
+    private static final long serialVersionUID = -8946294032165677602L;
+
+    @Override
+    public void execute(FunctionContext<Boolean> context) {
+        RegionFunctionContext regionContext = (RegionFunctionContext) context;
+        Region<CustomerKey, Customer> region = regionContext.getDataSet();
+
+        for (Map.Entry<CustomerKey, Customer> entry : region.entrySet()) {
+            Customer customer = entry.getValue();
+            customer.setFirstName(customer.getFirstName()
+                .toUpperCase());
+        }
+
+        context.getResultSender()
+            .lastResult(true);
+    }
+
+    @Override
+    public String getId() {
+        return getClass().getName();
+    }
+}

apache-geode/src/test/java/com/baeldung/geode/GeodeSamplesIntegrationTest.java

@@ -0,0 +1,110 @@
+package com.baeldung.geode;
+
+import com.baeldung.geode.functions.UpperCaseNames;
+import org.apache.geode.cache.Region;
+import org.apache.geode.cache.client.ClientCache;
+import org.apache.geode.cache.client.ClientCacheFactory;
+import org.apache.geode.cache.client.ClientRegionShortcut;
+import org.apache.geode.cache.execute.Execution;
+import org.apache.geode.cache.execute.FunctionService;
+import org.apache.geode.cache.query.*;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.junit.Assert.assertEquals;
+
+public class GeodeSamplesIntegrationTest {
+
+    ClientCache cache = null;
+    Region<String, String> region = null;
+    Region<Integer, Customer> queryRegion = null;
+    Region<CustomerKey, Customer> customerRegion = null;
+
+    @Before
+    public void connect() {
+        this.cache = new ClientCacheFactory().addPoolLocator("localhost", 10334)
+            .create();
+        this.region = this.cache.<String, String> createClientRegionFactory(ClientRegionShortcut.CACHING_PROXY)
+            .create("baeldung");
+        this.customerRegion = this.cache.<CustomerKey, Customer> createClientRegionFactory(ClientRegionShortcut.CACHING_PROXY)
+            .create("baeldung-customers");
+    }
+
+    @After
+    public void cleanup() {
+        this.cache.close();
+    }
+
+    @Test
+    public void whenSendMessageToRegion_thenMessageSavedSuccessfully() {
+
+        this.region.put("1", "Hello");
+        this.region.put("2", "Baeldung");
+
+        assertEquals("Hello", region.get("1"));
+        assertEquals("Baeldung", region.get("2"));
+
+    }
+
+    @Test
+    public void whenPutMultipleValuesAtOnce_thenValuesSavedSuccessfully() {
+
+        Supplier<Stream<String>> keys = () -> Stream.of("A", "B", "C", "D", "E");
+        Map<String, String> values = keys.get()
+            .collect(Collectors.toMap(Function.identity(), String::toLowerCase));
+
+        this.region.putAll(values);
+
+        keys.get()
+            .forEach(k -> assertEquals(k.toLowerCase(), this.region.get(k)));
+
+    }
+
+    @Test
+    public void whenPutCustomKey_thenValuesSavedSuccessfully() {
+        CustomerKey key = new CustomerKey(123);
+        Customer customer = new Customer(key, "William", "Russell", 35);
+
+        Map<CustomerKey, Customer> customerInfo = new HashMap<>();
+        customerInfo.put(key, customer);
+
+        this.customerRegion.putAll(customerInfo);
+
+        Customer storedCustomer = this.customerRegion.get(key);
+        assertEquals("William", storedCustomer.getFirstName());
+        assertEquals("Russell", storedCustomer.getLastName());
+
+    }
+
+    @Test
+    public void whenFindACustomerUsingOQL_thenCorrectCustomerObject() throws NameResolutionException, TypeMismatchException, QueryInvocationTargetException, FunctionDomainException {
+
+        Map<CustomerKey, Customer> data = new HashMap<>();
+        data.put(new CustomerKey(1), new Customer("Gheorge", "Manuc", 36));
+        data.put(new CustomerKey(2), new Customer("Allan", "McDowell", 43));
+        this.customerRegion.putAll(data);
+
+        QueryService queryService = this.cache.getQueryService();
+        String query = "select * from /baeldung-customers c where c.firstName = 'Allan'";
+        SelectResults<Customer> queryResults = (SelectResults<Customer>) queryService.newQuery(query)
+            .execute();
+        assertEquals(1, queryResults.size());
+
+    }
+
+    @Test
+    public void whenExecuteUppercaseNames_thenCustomerNamesAreUppercased() {
+        Execution execution = FunctionService.onRegion(this.customerRegion);
+        execution.execute(UpperCaseNames.class.getName());
+        Customer customer = this.customerRegion.get(new CustomerKey(1));
+        assertEquals("GHEORGE", customer.getFirstName());
+    }
+}

apache-shiro/pom.xml

@@ -3,7 +3,6 @@
          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>apache-shiro</artifactId>
     <version>1.0-SNAPSHOT</version>
 
@@ -36,13 +35,11 @@
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>jcl-over-slf4j</artifactId>
-            <version>${slf4j-version}</version>
             <scope>runtime</scope>
         </dependency>
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-log4j12</artifactId>
-            <version>${slf4j-version}</version>
             <scope>runtime</scope>
         </dependency>
         <dependency>
@@ -53,26 +50,9 @@
         </dependency>
     </dependencies>
 
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <version>${maven-compiler-plugin.version}</version>
-                <configuration>
-                    <source>${java.version}</source>
-                    <target>${java.version}</target>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
-
     <properties>
         <apache-shiro-core-version>1.4.0</apache-shiro-core-version>
-        <maven-compiler-plugin.version>3.7.0</maven-compiler-plugin.version>
-        <java.version>1.8</java.version>
         <log4j-version>1.2.17</log4j-version>
-        <slf4j-version>1.7.25</slf4j-version>
     </properties>
 
 </project>

asciidoctor/README.md

@@ -1,5 +1,4 @@
 ### Relevant articles
 
-- [Introduction to Asciidoctor](http://www.baeldung.com/introduction-to-asciidoctor)
 - [Generating a Book with Asciidoctor](http://www.baeldung.com/asciidoctor-book)
 - [Introduction to Asciidoctor in Java](http://www.baeldung.com/asciidoctor)

asciidoctor/pom.xml

@@ -61,9 +61,10 @@
     </build>
 
     <properties>
-        <asciidoctor-maven-plugin.version>1.5.5</asciidoctor-maven-plugin.version>
-        <asciidoctorj.version>1.5.4</asciidoctorj.version>
-        <asciidoctorj-pdf.src.version>1.5.0-alpha.11</asciidoctorj-pdf.src.version>
+        <asciidoctor-maven-plugin.version>1.5.6</asciidoctor-maven-plugin.version>
+        <asciidoctorj.version>1.5.6</asciidoctorj.version>
+        
+        <asciidoctorj-pdf.version>1.5.0-alpha.15</asciidoctorj-pdf.version>
         <asciidoctorj-pdf.plugin.version>1.5.0-alpha.15</asciidoctorj-pdf.plugin.version>
     </properties>
 

asciidoctor/src/test/java/com/baeldung/asciidoctor/AsciidoctorDemoIntegrationTest.java

@@ -3,7 +3,7 @@ package com.baeldung.asciidoctor;
 import org.junit.Assert;
 import org.junit.Test;
 
-public class AsciidoctorDemoTest {
+public class AsciidoctorDemoIntegrationTest {
 
     @Test
     public void givenString_whenConverting_thenResultingHTMLCode() {

asm/pom.xml

@@ -42,14 +42,6 @@
                     </archive>
                 </configuration>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <version>${maven-surefire-plugin.version}</version>
-                <configuration>
-                    <argLine>-javaagent:"C:\asm-1.0.jar"</argLine>
-                </configuration>
-            </plugin>
         </plugins>
     </build>
 

cas/cas-secured-app/pom.xml

@@ -2,12 +2,10 @@
 <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>cas-secured-app</artifactId>
-    <version>0.0.1-SNAPSHOT</version>
     <packaging>jar</packaging>
     <name>cas-secured-app</name>
-    <description>Demo project for Spring Boot</description>
+    <description>Demo project for CAS</description>
 
     <parent>
         <artifactId>parent-boot-1</artifactId>
@@ -60,10 +58,4 @@
         </plugins>
     </build>
 
-    <properties>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
-        <java.version>1.8</java.version>
-    </properties>
-
 </project>

cas/cas-server/pom.xml

@@ -2,11 +2,17 @@
 <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>cas-server</artifactId>
     <packaging>war</packaging>
     <version>1.0</version>
 
+    <parent>
+        <artifactId>parent-boot-1</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-1</relativePath>
+    </parent>
+    
     <dependencies>
         <dependency>
             <groupId>org.apereo.cas</groupId>
@@ -39,7 +45,6 @@
             <plugin>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-maven-plugin</artifactId>
-                <version>${springboot.version}</version>
                 <configuration>
                     <mainClass>${mainClassName}</mainClass>
                     <addResources>true</addResources>
@@ -74,42 +79,10 @@
                     </overlays>
                 </configuration>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <version>${maven-compiler-plugin.version}</version>
-            </plugin>
         </plugins>
         <finalName>cas</finalName>
     </build>
 
-    <repositories>
-        <repository>
-            <id>sonatype-releases</id>
-            <url>http://oss.sonatype.org/content/repositories/releases/</url>
-            <snapshots>
-                <enabled>false</enabled>
-            </snapshots>
-            <releases>
-                <enabled>true</enabled>
-            </releases>
-        </repository>
-        <repository>
-            <id>sonatype-snapshots</id>
-            <url>https://oss.sonatype.org/content/repositories/snapshots/</url>
-            <snapshots>
-                <enabled>true</enabled>
-            </snapshots>
-            <releases>
-                <enabled>false</enabled>
-            </releases>
-        </repository>
-        <repository>
-            <id>shibboleth-releases</id>
-            <url>https://build.shibboleth.net/nexus/content/repositories/releases</url>
-        </repository>
-    </repositories>
-
     <profiles>
         <profile>
             <activation>
@@ -214,8 +187,7 @@
     </profiles>
 
     <properties>
-        <cas.version>5.3.0-SNAPSHOT</cas.version>
-        <springboot.version>1.5.13.RELEASE</springboot.version>
+        <cas.version>5.3.3</cas.version>
         <!-- app.server could be -jetty, -undertow, -tomcat, or blank if you plan to provide appserver -->
         <app.server>-tomcat</app.server>
 
@@ -223,12 +195,10 @@
         <isExecutable>false</isExecutable>
         <manifestFileToUse>${project.build.directory}/war/work/org.apereo.cas/cas-server-webapp${app.server}/META-INF/MANIFEST.MF</manifestFileToUse>
 
-        <maven.compiler.source>1.8</maven.compiler.source>
-        <maven.compiler.target>1.8</maven.compiler.target>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <wrapper-maven-plugin.version>0.0.4</wrapper-maven-plugin.version>
         <maven-war-plugin.version>2.6</maven-war-plugin.version>
         <maven-compiler-plugin.version>3.3</maven-compiler-plugin.version>
+        
         <echo-maven-plugin.version>0.3.0</echo-maven-plugin.version>
         <pgpverify-maven-plugin.version>1.1.0</pgpverify-maven-plugin.version>
     </properties>

cdi-portable-extension/flyway-cdi/pom.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>flyway-cdi</artifactId>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>cdi-portable-extension</artifactId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>javax.enterprise</groupId>
+            <artifactId>cdi-api</artifactId>
+            <version>2.0.SP1</version>
+        </dependency>
+        <dependency>
+            <groupId>org.flywaydb</groupId>
+            <artifactId>flyway-core</artifactId>
+            <version>5.1.4</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.tomcat</groupId>
+            <artifactId>tomcat-jdbc</artifactId>
+            <version>8.5.33</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.annotation</groupId>
+            <artifactId>javax.annotation-api</artifactId>
+            <version>1.3.2</version>
+        </dependency>
+    </dependencies>
+
+</project>

cdi-portable-extension/flyway-cdi/src/main/java/com/baeldung/cdi/extension/FlywayExtension.java

@@ -0,0 +1,74 @@
+package com.baeldung.cdi.extension;
+
+import org.apache.tomcat.jdbc.pool.DataSource;
+import org.flywaydb.core.Flyway;
+
+import javax.annotation.sql.DataSourceDefinition;
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.event.Observes;
+import javax.enterprise.inject.Any;
+import javax.enterprise.inject.Default;
+import javax.enterprise.inject.literal.InjectLiteral;
+import javax.enterprise.inject.spi.*;
+import javax.enterprise.util.AnnotationLiteral;
+
+
+/**
+ * Flyway is now under CDI container like:
+ *
+ * @ApplicationScoped
+ * @FlywayType public class Flyway{
+ * @Inject setDataSource(DataSource dataSource){
+ * //...
+ * }
+ * }
+ */
+
+public class FlywayExtension implements Extension {
+
+    DataSourceDefinition dataSourceDefinition = null;
+
+    public void registerFlywayType(@Observes BeforeBeanDiscovery bbdEvent) {
+        bbdEvent.addAnnotatedType(Flyway.class, Flyway.class.getName());
+    }
+
+    public void detectDataSourceDefinition(@Observes @WithAnnotations(DataSourceDefinition.class) ProcessAnnotatedType<?> patEvent) {
+        AnnotatedType at = patEvent.getAnnotatedType();
+        dataSourceDefinition = at.getAnnotation(DataSourceDefinition.class);
+    }
+
+    public void processAnnotatedType(@Observes ProcessAnnotatedType<Flyway> patEvent) {
+        patEvent.configureAnnotatedType()
+                //Add Scope
+                .add(ApplicationScoped.Literal.INSTANCE)
+                //Add Qualifier
+                .add(new AnnotationLiteral<FlywayType>() {
+                })
+                //Decorate setDataSource(DataSource dataSource){} with @Inject
+                .filterMethods(annotatedMethod -> {
+                    return annotatedMethod.getParameters().size() == 1 &&
+                            annotatedMethod.getParameters().get(0).getBaseType().equals(javax.sql.DataSource.class);
+                })
+                .findFirst().get().add(InjectLiteral.INSTANCE);
+    }
+
+    void afterBeanDiscovery(@Observes AfterBeanDiscovery abdEvent, BeanManager bm) {
+        abdEvent.addBean()
+                .types(javax.sql.DataSource.class, DataSource.class)
+                .qualifiers(new AnnotationLiteral<Default>() {}, new AnnotationLiteral<Any>() {})
+                .scope(ApplicationScoped.class)
+                .name(DataSource.class.getName())
+                .beanClass(DataSource.class)
+                .createWith(creationalContext -> {
+                    DataSource instance = new DataSource();
+                    instance.setUrl(dataSourceDefinition.url());
+                    instance.setDriverClassName(dataSourceDefinition.className());
+                    return instance;
+                });
+    }
+
+    void runFlywayMigration(@Observes AfterDeploymentValidation adv, BeanManager manager) {
+        Flyway flyway = manager.createInstance().select(Flyway.class, new AnnotationLiteral<FlywayType>() {}).get();
+        flyway.migrate();
+    }
+}

cdi-portable-extension/flyway-cdi/src/main/java/com/baeldung/cdi/extension/FlywayType.java

@@ -0,0 +1,14 @@
+package com.baeldung.cdi.extension;
+
+import javax.inject.Qualifier;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.*;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target({FIELD, METHOD, PARAMETER, TYPE})
+@Qualifier
+public @interface FlywayType {
+}

cdi-portable-extension/flyway-cdi/src/main/resources/META-INF/beans.xml

@@ -0,0 +1,6 @@
+<beans version="2.0" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
+		http://xmlns.jcp.org/xml/ns/javaee/beans_2_0.xsd"
+       bean-discovery-mode="annotated">
+</beans>

cdi-portable-extension/flyway-cdi/src/main/resources/META-INF/services/javax.enterprise.inject.spi.Extension

@@ -0,0 +1,2 @@
+com.baeldung.cdi.extension.FlywayExtension
+

cdi-portable-extension/main-app/pom.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>main-app</artifactId>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>cdi-portable-extension</artifactId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+
+        <dependency>
+            <groupId>javax.enterprise</groupId>
+            <artifactId>cdi-api</artifactId>
+            <version>2.0.SP1</version>
+        </dependency>
+        <dependency>
+            <groupId>org.jboss.weld.se</groupId>
+            <artifactId>weld-se-core</artifactId>
+            <version>3.0.5.Final</version>
+            <scope>runtime</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>com.baeldung</groupId>
+            <artifactId>flyway-cdi</artifactId>
+            <version>1.0-SNAPSHOT</version>
+            <scope>runtime</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <version>1.4.197</version>
+            <scope>runtime</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>javax.annotation</groupId>
+            <artifactId>javax.annotation-api</artifactId>
+            <version>1.3.2</version>
+        </dependency>
+
+    </dependencies>
+
+</project>

cdi-portable-extension/main-app/src/main/java/com/baeldung/cdi/extension/MainApp.java

@@ -0,0 +1,16 @@
+package com.baeldung.cdi.extension;
+
+import javax.annotation.sql.DataSourceDefinition;
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.inject.se.SeContainer;
+import javax.enterprise.inject.se.SeContainerInitializer;
+
+@ApplicationScoped
+@DataSourceDefinition(name = "ds", className = "org.h2.Driver", url = "jdbc:h2:mem:testdb")
+public class MainApp {
+    public static void main(String[] args) {
+        SeContainerInitializer initializer = SeContainerInitializer.newInstance();
+        try (SeContainer container = initializer.initialize()) {
+        }
+    }
+}

cdi-portable-extension/main-app/src/main/resources/META-INF/beans.xml

@@ -0,0 +1,6 @@
+<beans version="2.0" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
+		http://xmlns.jcp.org/xml/ns/javaee/beans_2_0.xsd"
+       bean-discovery-mode="annotated">
+</beans>

cdi-portable-extension/main-app/src/main/resources/db/migration/V1__Create_person_table.sql

@@ -0,0 +1,4 @@
+create table PERSON (
+    ID int not null,
+    NAME varchar(100) not null
+);

cdi-portable-extension/main-app/src/main/resources/db/migration/V2__Add_people.sql

@@ -0,0 +1,3 @@
+insert into PERSON (ID, NAME) values (1, 'Axel');
+insert into PERSON (ID, NAME) values (2, 'Mr. Foo');
+insert into PERSON (ID, NAME) values (3, 'Ms. Bar');

cdi-portable-extension/pom.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>cdi-portable-extension</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>pom</packaging>
+
+    <properties>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+
+    <modules>
+        <module>main-app</module>
+        <module>flyway-cdi</module>
+    </modules>
+
+    <dependencies>
+        <dependency>
+            <groupId>javax.enterprise</groupId>
+            <artifactId>cdi-api</artifactId>
+            <version>2.0.SP1</version>
+        </dependency>
+    </dependencies>
+
+</project>

core-java-8/src/test/java/com/baeldung/stream/conditional/StreamForEachIfElseUnitTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.stream.conditional;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class StreamForEachIfElseUnitTest {
+
+    @Test
+    public final void givenIntegerStream_whenCheckingIntegerParityWithIfElse_thenEnsureCorrectParity() {
+        List<Integer> ints = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+
+        ints.stream()
+            .forEach(i -> {
+                if (i.intValue() % 2 == 0) {
+                    Assert.assertTrue(i.intValue() + " is not even", i.intValue() % 2 == 0);
+                } else {
+                    Assert.assertTrue(i.intValue() + " is not odd", i.intValue() % 2 != 0);
+                }
+            });
+
+    }
+
+    @Test
+    public final void givenIntegerStream_whenCheckingIntegerParityWithStreamFilter_thenEnsureCorrectParity() {
+        List<Integer> ints = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+
+        Stream<Integer> evenIntegers = ints.stream()
+            .filter(i -> i.intValue() % 2 == 0);
+        Stream<Integer> oddIntegers = ints.stream()
+            .filter(i -> i.intValue() % 2 != 0);
+
+        evenIntegers.forEach(i -> Assert.assertTrue(i.intValue() + " is not even", i.intValue() % 2 == 0));
+        oddIntegers.forEach(i -> Assert.assertTrue(i.intValue() + " is not odd", i.intValue() % 2 != 0));
+
+    }
+
+}

core-java-collections/README.md

@@ -48,4 +48,6 @@
 - [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)
-- [](https://www.baeldung.com/java-hashset-arraylist-contains-performance)
+- [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)

core-java-collections/pom.xml

@@ -63,6 +63,12 @@
             <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>
 
 

core-java-collections/src/main/java/com/baeldung/combiningcollections/CombiningArrays.java

@@ -0,0 +1,39 @@
+package com.baeldung.combiningcollections;
+
+import java.util.Arrays;
+import java.util.stream.Stream;
+
+import org.apache.commons.lang3.ArrayUtils;
+
+import com.google.common.collect.ObjectArrays;
+
+public class CombiningArrays {
+    
+    public static Object[] usingNativeJava(Object[] first, Object[] second) {
+        Object[] combined = new Object[first.length + second.length];
+        System.arraycopy(first, 0, combined, 0, first.length);
+        System.arraycopy(second, 0, combined, first.length, second.length);
+        return combined;
+    }
+    
+    public static Object[] usingJava8ObjectStream(Object[] first, Object[] second) {
+        Object[] combined = Stream.concat(Arrays.stream(first), Arrays.stream(second)).toArray();
+        return combined;
+    }
+
+    public static Object[] usingJava8FlatMaps(Object[] first, Object[] second) {
+        Object[] combined = Stream.of(first, second).flatMap(Stream::of).toArray(String[]::new);
+        return combined;
+    }
+    
+    public static Object[] usingApacheCommons(Object[] first, Object[] second) {
+        Object[] combined = ArrayUtils.addAll(first, second);
+        return combined;
+    }
+
+    public static Object[] usingGuava(Object[] first, Object[] second) {
+        Object [] combined = ObjectArrays.concat(first, second, Object.class);
+        return combined;
+    }
+    
+}

core-java-collections/src/main/java/com/baeldung/combiningcollections/CombiningLists.java

@@ -0,0 +1,46 @@
+package com.baeldung.combiningcollections;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.apache.commons.collections4.ListUtils;
+
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
+
+public class CombiningLists {
+    
+    public static List<Object> usingNativeJava(List<Object> first, List<Object> second) {
+        List<Object> combined = new ArrayList<>();
+        combined.addAll(first);
+        combined.addAll(second);
+        return combined;
+    }
+    
+    public static List<Object> usingJava8ObjectStream(List<Object> first, List<Object> second) {
+        List<Object> combined = Stream.concat(first.stream(), second.stream()).collect(Collectors.toList());
+        return combined;
+    }
+
+    public static List<Object> usingJava8FlatMaps(List<Object> first, List<Object> second) {
+        List<Object> combined = Stream.of(first, second).flatMap(Collection::stream).collect(Collectors.toList());
+        return combined;
+    }
+    
+    public static List<Object> usingApacheCommons(List<Object> first, List<Object> second) {
+        List<Object> combined = ListUtils.union(first, second);
+        return combined;
+    }
+
+    public static List<Object> usingGuava(List<Object> first, List<Object> second) {
+        Iterable<Object> combinedIterables = Iterables.unmodifiableIterable(
+        Iterables.concat(first, second));
+        
+        List<Object> combined = Lists.newArrayList(combinedIterables);
+        return combined;
+    }
+    
+}

core-java-collections/src/main/java/com/baeldung/combiningcollections/CombiningMaps.java

@@ -0,0 +1,47 @@
+package com.baeldung.combiningcollections;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.apache.commons.exec.util.MapUtils;
+
+import com.google.common.collect.ImmutableMap;
+
+public class CombiningMaps {
+    
+    public static Map<String, String> usingPlainJava(Map<String, String> first, Map<String, String> second) {
+    	Map<String, String> combined = new HashMap<>();
+    	combined.putAll(first);
+    	combined.putAll(second);
+        return combined;
+    }
+    
+    public static Map<String, String> usingJava8ForEach(Map<String, String> first, Map<String, String> second) {
+    	second.forEach((key, value) -> first.merge(key, value, String::concat));
+        return first;
+    }
+
+    public static Map<String, String> usingJava8FlatMaps(Map<String, String> first, Map<String, String> second) {
+		Map<String, String> combined = Stream.of(first, second).map(Map::entrySet).flatMap(Collection::stream)
+				.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, String::concat));
+		return combined;
+
+    }
+    
+    public static Map<String, String> usingApacheCommons(Map<String, String> first, Map<String, String> second) {
+        Map<String, String> combined = MapUtils.merge(first, second);
+        return combined;
+    }
+
+    public static Map<String, String> usingGuava(Map<String, String> first, Map<String, String> second) {
+        Map<String, String> combined = ImmutableMap.<String, String>builder()
+          .putAll(first)
+          .putAll(second)
+          .build();
+        return combined;
+    }
+    
+}

core-java-collections/src/main/java/com/baeldung/combiningcollections/CombiningSets.java

@@ -0,0 +1,42 @@
+package com.baeldung.combiningcollections;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.apache.commons.collections4.SetUtils;
+
+import com.google.common.collect.Sets;
+
+public class CombiningSets {
+    
+    public static Set<Object> usingNativeJava(Set<Object> first, Set<Object> second) {
+        Set<Object> combined = new HashSet<>();
+        combined.addAll(first);
+        combined.addAll(second);
+        return combined;
+    }
+    
+    public static Set<Object> usingJava8ObjectStream(Set<Object> first, Set<Object> second) {
+        Set<Object> combined = Stream.concat(first.stream(), second.stream()).collect(Collectors.toSet());
+        return combined;
+    }
+
+    public static Set<Object> usingJava8FlatMaps(Set<Object> first, Set<Object> second) {
+        Set<Object> combined = Stream.of(first, second).flatMap(Collection::stream).collect(Collectors.toSet());
+        return combined;
+    }
+    
+    public static Set<Object> usingApacheCommons(Set<Object> first, Set<Object> second) {
+        Set<Object> combined = SetUtils.union(first, second);
+        return combined;
+    }
+
+    public static Set<Object> usingGuava(Set<Object> first, Set<Object> second) {
+        Set<Object> combined = Sets.union(first, second);
+        return combined;
+    }
+    
+}

core-java-collections/src/main/java/com/baeldung/map/util/MapMax.java

@@ -0,0 +1,96 @@
+package com.baeldung.map.util;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Optional;
+
+public class MapMax {
+
+    public <K, V extends Comparable<V>> V maxUsingIteration(Map<K, V> map) {
+
+        Map.Entry<K, V> maxEntry = null;
+
+        for (Map.Entry<K, V> entry : map.entrySet()) {
+
+            if (maxEntry == null || entry.getValue()
+                .compareTo(maxEntry.getValue()) > 0) {
+                maxEntry = entry;
+            }
+        }
+
+        return maxEntry.getValue();
+    }
+
+    public <K, V extends Comparable<V>> V maxUsingCollectionsMax(Map<K, V> map) {
+
+        Entry<K, V> maxEntry = Collections.max(map.entrySet(), new Comparator<Entry<K, V>>() {
+            public int compare(Entry<K, V> e1, Entry<K, V> e2) {
+                return e1.getValue()
+                    .compareTo(e2.getValue());
+            }
+        });
+
+        return maxEntry.getValue();
+    }
+
+    public <K, V extends Comparable<V>> V maxUsingCollectionsMaxAndLambda(Map<K, V> map) {
+
+        Entry<K, V> maxEntry = Collections.max(map.entrySet(), (Entry<K, V> e1, Entry<K, V> e2) -> e1.getValue()
+            .compareTo(e2.getValue()));
+
+        return maxEntry.getValue();
+    }
+
+    public <K, V extends Comparable<V>> V maxUsingCollectionsMaxAndMethodReference(Map<K, V> map) {
+
+        Entry<K, V> maxEntry = Collections.max(map.entrySet(), Comparator.comparing(Map.Entry::getValue));
+
+        return maxEntry.getValue();
+    }
+
+    public <K, V extends Comparable<V>> V maxUsingStreamAndLambda(Map<K, V> map) {
+
+        Optional<Entry<K, V>> maxEntry = map.entrySet()
+            .stream()
+            .max((Entry<K, V> e1, Entry<K, V> e2) -> e1.getValue()
+                .compareTo(e2.getValue()));
+
+        return maxEntry.get()
+            .getValue();
+    }
+
+    public <K, V extends Comparable<V>> V maxUsingStreamAndMethodReference(Map<K, V> map) {
+
+        Optional<Entry<K, V>> maxEntry = map.entrySet()
+            .stream()
+            .max(Comparator.comparing(Map.Entry::getValue));
+
+        return maxEntry.get()
+            .getValue();
+    }
+
+    public static void main(String[] args) {
+
+        Map<Integer, Integer> map = new HashMap<Integer, Integer>();
+
+        map.put(1, 3);
+        map.put(2, 4);
+        map.put(3, 5);
+        map.put(4, 6);
+        map.put(5, 7);
+        
+        MapMax mapMax = new MapMax();
+
+        System.out.println(mapMax.maxUsingIteration(map));
+        System.out.println(mapMax.maxUsingCollectionsMax(map));
+        System.out.println(mapMax.maxUsingCollectionsMaxAndLambda(map));
+        System.out.println(mapMax.maxUsingCollectionsMaxAndMethodReference(map));
+        System.out.println(mapMax.maxUsingStreamAndLambda(map));
+        System.out.println(mapMax.maxUsingStreamAndMethodReference(map));
+
+    }
+
+}

core-java-collections/src/main/java/com/baeldung/performance/Employee.java

@@ -44,4 +44,12 @@ public class Employee {
         result = 31 * result + name.hashCode();
         return result;
     }
+
+    @Override
+    public String toString() {
+        return "Employee{" +
+                "id=" + id +
+                ", name='" + name + '\'' +
+                '}';
+    }
 }

core-java-collections/src/main/java/com/baeldung/sort/Employee.java

@@ -0,0 +1,60 @@
+package com.baeldung.sort;
+
+public class Employee implements Comparable<Employee> {
+
+    private Long id;
+    private String name;
+
+    public Employee(Long id, String name) {
+        this.name = name;
+        this.id = id;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Employee employee = (Employee) o;
+
+        if (!id.equals(employee.id)) return false;
+        return name.equals(employee.name);
+
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id.hashCode();
+        result = 31 * result + name.hashCode();
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "Employee{" +
+                "id=" + id +
+                ", name='" + name + '\'' +
+                '}';
+    }
+
+    @Override
+    public int compareTo(Employee employee) {
+        return (int)(this.id - employee.getId());
+    }
+}

core-java-collections/src/main/java/com/baeldung/sort/SortHashMap.java

@@ -0,0 +1,104 @@
+package com.baeldung.sort;
+
+import com.google.common.base.Functions;
+import com.google.common.collect.ImmutableSortedMap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Ordering;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class SortHashMap {
+
+    private static Map<String, Employee> map = new HashMap<>();
+
+    public static void main(String[] args) {
+
+        initialize();
+
+        treeMapSortByKey();
+
+        arrayListSortByValue();
+        arrayListSortByKey();
+
+        sortStream();
+
+        sortGuava();
+
+        addDuplicates();
+
+        treeSetByKey();
+        treeSetByValue();
+
+    }
+
+    private static void sortGuava() {
+        final Ordering naturalOrdering =
+        Ordering.natural().onResultOf(Functions.forMap(map, null));
+
+        System.out.println(ImmutableSortedMap.copyOf(map, naturalOrdering));
+    }
+
+    private static void sortStream() {
+        map.entrySet().stream()
+                .sorted(Map.Entry.<String, Employee>comparingByKey().reversed())
+                .forEach(System.out::println);
+
+        Map<String, Employee> result = map.entrySet().stream()
+                .sorted(Map.Entry.comparingByValue())
+                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
+                (oldValue, newValue) -> oldValue, LinkedHashMap::new));
+
+        result.entrySet().forEach(System.out::println);
+    }
+
+    private static void treeSetByValue() {
+        SortedSet<Employee> values = new TreeSet<>(map.values());
+        System.out.println(values);
+    }
+
+    private static void treeSetByKey() {
+        SortedSet<String> keysSet = new TreeSet<>(map.keySet());
+        System.out.println(keysSet);
+    }
+
+    private static void treeMapSortByKey() {
+        TreeMap<String, Employee> sorted = new TreeMap<>(map);
+        sorted.putAll(map);
+
+        sorted.entrySet().forEach(System.out::println);
+
+    }
+
+    private static void arrayListSortByValue() {
+        List<Employee> employeeById = new ArrayList<>(map.values());
+
+        Collections.sort(employeeById);
+
+        System.out.println(employeeById);
+    }
+
+    private static void arrayListSortByKey() {
+        List<String> employeeByKey = new ArrayList<>(map.keySet());
+        Collections.sort(employeeByKey);
+        System.out.println(employeeByKey);
+    }
+
+    private static void initialize() {
+        Employee employee1 = new Employee(1L, "Mher");
+        map.put(employee1.getName(), employee1);
+        Employee employee2 = new Employee(22L, "Annie");
+        map.put(employee2.getName(), employee2);
+        Employee employee3 = new Employee(8L, "John");
+        map.put(employee3.getName(), employee3);
+        Employee employee4 = new Employee(2L, "George");
+        map.put(employee4.getName(), employee4);
+    }
+
+    private static void addDuplicates() {
+        Employee employee5 = new Employee(1L, "Mher");
+        map.put(employee5.getName(), employee5);
+        Employee employee6 = new Employee(22L, "Annie");
+        map.put(employee6.getName(), employee6);
+    }
+}

core-java-collections/src/test/java/com/baeldung/combiningcollections/CombiningArraysUnitTest.java

@@ -0,0 +1,52 @@
+package com.baeldung.combiningcollections;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+
+public class CombiningArraysUnitTest {
+    private static final String first[] = {
+            "One", 
+            "Two", 
+            "Three"
+    };
+    
+    private static final String second[] = {
+            "Four", 
+            "Five", 
+            "Six"
+    };
+
+    private static final String expected[] = {
+            "One", 
+            "Two", 
+            "Three",
+            "Four", 
+            "Five", 
+            "Six"
+    };
+    
+    @Test
+    public void givenTwoArrays_whenUsingNativeJava_thenArraysCombined() {
+        assertArrayEquals(expected, CombiningArrays.usingNativeJava(first, second));
+    }
+
+    @Test
+    public void givenTwoArrays_whenUsingObjectStreams_thenArraysCombined() {
+        assertArrayEquals(expected, CombiningArrays.usingJava8ObjectStream(first, second));
+    }
+
+    @Test
+    public void givenTwoArrays_whenUsingFlatMaps_thenArraysCombined() {
+        assertArrayEquals(expected, CombiningArrays.usingJava8FlatMaps(first, second));
+    }
+
+    @Test
+    public void givenTwoArrays_whenUsingApacheCommons_thenArraysCombined() {
+        assertArrayEquals(expected, CombiningArrays.usingApacheCommons(first, second));
+    }
+
+    @Test
+    public void givenTwoArrays_whenUsingGuava_thenArraysCombined() {
+        assertArrayEquals(expected, CombiningArrays.usingGuava(first, second));
+    }
+}

core-java-collections/src/test/java/com/baeldung/combiningcollections/CombiningListsUnitTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.combiningcollections;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Test;
+
+public class CombiningListsUnitTest {
+    private static final List<Object> first = Arrays.asList(new Object[]{
+            "One", 
+            "Two", 
+            "Three"
+    });
+    
+    private static final List<Object> second = Arrays.asList(new Object[]{
+            "Four", 
+            "Five", 
+            "Six"
+    });
+
+    private static final List<Object> expected = Arrays.asList(new Object[]{
+            "One", 
+            "Two", 
+            "Three",
+            "Four", 
+            "Five", 
+            "Six"
+    });
+    
+    @Test
+    public void givenTwoLists_whenUsingNativeJava_thenArraysCombined() {
+    	assertThat(CombiningLists.usingNativeJava(first, second), is(expected));
+    }
+
+    @Test
+    public void givenTwoLists_whenUsingObjectStreams_thenArraysCombined() {
+        assertThat(CombiningLists.usingJava8ObjectStream(first, second), is(expected));
+    }
+
+    @Test
+    public void givenTwoLists_whenUsingFlatMaps_thenArraysCombined() {
+        assertThat(CombiningLists.usingJava8FlatMaps(first, second), is(expected));
+    }
+
+    @Test
+    public void givenTwoLists_whenUsingApacheCommons_thenArraysCombined() {
+        assertThat(CombiningLists.usingApacheCommons(first, second), is(expected));
+    }
+
+    @Test
+    public void givenTwoLists_whenUsingGuava_thenArraysCombined() {
+        assertThat(CombiningLists.usingGuava(first, second), is(expected));
+    }
+}

core-java-collections/src/test/java/com/baeldung/combiningcollections/CombiningMapsUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.combiningcollections;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Test;
+
+public class CombiningMapsUnitTest {
+    private static final Map<String, String> first = new HashMap<>();
+    private static final Map<String, String> second = new HashMap<>();
+    private static Map<String, String> expected = new HashMap<>();
+    
+    static {
+    	first.put("one", "first String");
+    	first.put("two", "second String");
+    	
+    	second.put("three", "third String");
+    	second.put("four", "fourth String");
+
+    	expected.put("one", "first String");
+    	expected.put("two", "second String");
+    	expected.put("three", "third String");
+    	expected.put("four", "fourth String");
+    }
+    
+    @Test
+    public void givenTwoMaps_whenUsingNativeJava_thenMapsCombined() {
+    	assertThat(CombiningMaps.usingPlainJava(first, second), is(expected));
+    }
+
+    
+    @Test
+    public void givenTwoMaps_whenUsingForEach_thenMapsCombined() {
+    	assertThat(CombiningMaps.usingJava8ForEach(first, second), is(expected));
+    }
+    
+    @Test
+    public void givenTwoMaps_whenUsingFlatMaps_thenMapsCombined() {
+    	assertThat(CombiningMaps.usingJava8FlatMaps(first, second), is(expected));
+    }
+    
+    @Test
+    public void givenTwoMaps_whenUsingApacheCommons_thenMapsCombined() {
+    	assertThat(CombiningMaps.usingApacheCommons(first, second), is(expected));
+    }
+    
+    @Test
+    public void givenTwoMaps_whenUsingGuava_thenMapsCombined() {
+    	assertThat(CombiningMaps.usingGuava(first, second), is(expected));
+    }
+}

core-java-collections/src/test/java/com/baeldung/combiningcollections/CombiningSetsUnitTest.java

@@ -0,0 +1,45 @@
+
+package com.baeldung.combiningcollections;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.junit.Test;
+
+public class CombiningSetsUnitTest {
+	private static final Set<Object> first = new HashSet<Object>(Arrays.asList(new Object[] { "One", "Two", "Three" }));
+
+	private static final Set<Object> second = new HashSet<Object>(Arrays.asList(new Object[] { "Four", "Five", "Six" }));
+
+	private static final Set<Object> expected = new HashSet<Object>(Arrays
+			.asList(new Object[] { "One", "Two", "Three", "Four", "Five", "Six" }));
+
+	@Test
+	public void givenTwoSets_whenUsingNativeJava_thenArraysCombined() {
+		assertThat(CombiningSets.usingNativeJava(first, second), is(expected));
+	}
+
+	@Test
+	public void givenTwoSets_whenUsingObjectStreams_thenArraysCombined() {
+		assertThat(CombiningSets.usingJava8ObjectStream(first, second), is(expected));
+	}
+
+	@Test
+	public void givenTwoSets_whenUsingFlatMaps_thenArraysCombined() {
+		assertThat(CombiningSets.usingJava8FlatMaps(first, second), is(expected));
+	}
+
+	@Test
+	public void givenTwoSets_whenUsingApacheCommons_thenArraysCombined() {
+		assertThat(CombiningSets.usingApacheCommons(first, second), is(expected));
+	}
+
+	@Test
+	public void givenTwoSets_whenUsingGuava_thenArraysCombined() {
+		assertThat(CombiningSets.usingGuava(first, second), is(expected));
+	}
+}

core-java-collections/src/test/java/com/baeldung/map/util/MapMaxUnitTest.java

@@ -0,0 +1,59 @@
+package com.baeldung.map.util;
+
+
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class MapMaxUnitTest {
+    
+    Map<Integer, Integer> map = null;
+    MapMax mapMax = null;
+        
+    
+    @Before
+    public void setupTestData() {
+        map = new HashMap<Integer, Integer>();
+        map.put(23, 12);
+        map.put(46, 24);
+        map.put(27, 38); 
+        mapMax = new MapMax();
+    }
+    
+    @Test
+    public void givenMap_whenIterated_thenReturnMaxValue() {
+        assertEquals(new Integer(38), mapMax.maxUsingIteration(map));
+    }
+    
+    @Test
+    public void givenMap_whenUsingCollectionsMax_thenReturnMaxValue() {
+        assertEquals(new Integer(38), mapMax.maxUsingCollectionsMax(map));
+    }
+    
+    @Test
+    public void givenMap_whenUsingCollectionsMaxAndLambda_thenReturnMaxValue() {
+        assertEquals(new Integer(38), mapMax.maxUsingCollectionsMaxAndLambda(map));
+    }
+    
+    @Test
+    public void givenMap_whenUsingCollectionsMaxAndMethodReference_thenReturnMaxValue() {
+        assertEquals(new Integer(38), mapMax.maxUsingCollectionsMaxAndMethodReference(map));
+    }
+    
+    @Test
+    public void givenMap_whenUsingStreamAndLambda_thenReturnMaxValue() {
+        assertEquals(new Integer(38), mapMax.maxUsingStreamAndLambda(map));
+    }
+    
+    @Test
+    public void givenMap_whenUsingStreamAndMethodReference_thenReturnMaxValue() {
+        assertEquals(new Integer(38), mapMax.maxUsingStreamAndMethodReference   (map));
+    }
+
+
+}

core-java-io/README.md

@@ -31,3 +31,4 @@
 - [Create a Symbolic Link with Java](http://www.baeldung.com/java-symlink)
 - [Quick Use of FilenameFilter](http://www.baeldung.com/java-filename-filter)
 - [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)
+- [ Read a File into an ArrayList](https://www.baeldung.com/java-file-to-arraylist)

core-java-io/pom.xml

@@ -1,7 +1,6 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-    <groupId>com.baeldung</groupId>
     <artifactId>core-java-io</artifactId>
     <version>0.1.0-SNAPSHOT</version>
     <packaging>jar</packaging>
@@ -166,36 +165,6 @@
             </resource>
         </resources>
         <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <configuration>
-                    <excludes>
-                        <exclude>**/*LiveTest.java</exclude>
-                        <exclude>**/*IntegrationTest.java</exclude>
-                        <exclude>**/*IntTest.java</exclude>
-                        <exclude>**/*LongRunningUnitTest.java</exclude>
-                        <exclude>**/*ManualTest.java</exclude>
-                    </excludes>
-                    <testFailureIgnore>true</testFailureIgnore>
-                </configuration>
-            </plugin>
-            <plugin>
-                <groupId>org.springframework.boot</groupId>
-                <artifactId>spring-boot-maven-plugin</artifactId>
-                <version>${spring-boot-maven-plugin.version}</version>
-                <executions>
-                    <execution>
-                        <goals>
-                            <goal>repackage</goal>
-                        </goals>
-                        <configuration>
-                            <classifier>spring-boot</classifier>
-                            <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>exec-maven-plugin</artifactId>
@@ -229,32 +198,6 @@
             <id>integration</id>
             <build>
                 <plugins>
-                    <plugin>
-                        <groupId>org.apache.maven.plugins</groupId>
-                        <artifactId>maven-surefire-plugin</artifactId>
-                        <executions>
-                            <execution>
-                                <phase>integration-test</phase>
-                                <goals>
-                                    <goal>test</goal>
-                                </goals>
-                                <configuration>
-                                    <excludes>
-                                        <exclude>**/*ManualTest.java</exclude>
-                                    </excludes>
-                                    <includes>
-                                        <include>**/*IntegrationTest.java</include>
-                                        <include>**/*IntTest.java</include>
-                                    </includes>
-                                </configuration>
-                            </execution>
-                        </executions>
-                        <configuration>
-                            <systemPropertyVariables>
-                                <test.mime>json</test.mime>
-                            </systemPropertyVariables>
-                        </configuration>
-                    </plugin>
                     <plugin>
                         <groupId>org.codehaus.mojo</groupId>
                         <artifactId>exec-maven-plugin</artifactId>
@@ -310,14 +253,11 @@
         <avaitility.version>1.7.0</avaitility.version>
 
         <!-- maven plugins -->
-        <maven.compiler.source>1.8</maven.compiler.source>
-        <maven.compiler.target>1.8</maven.compiler.target>
         <maven-javadoc-plugin.version>3.0.0-M1</maven-javadoc-plugin.version>
         <hsqldb.version>2.4.0</hsqldb.version>
         <esapi.version>2.1.0.1</esapi.version>
         <jmh-generator-annprocess.version>1.19</jmh-generator-annprocess.version>
         <async-http-client.version>2.4.5</async-http-client.version>
-        <spring-boot-maven-plugin.version>2.0.4.RELEASE</spring-boot-maven-plugin.version>
     </properties>
 
 </project>

core-java-io/src/main/java/com/baeldung/zip/ZipDirectory.java

@@ -24,6 +24,13 @@ public class ZipDirectory {
             return;
         }
         if (fileToZip.isDirectory()) {
+            if (fileName.endsWith("/")) {
+                zipOut.putNextEntry(new ZipEntry(fileName));
+                zipOut.closeEntry();
+            } else {
+                zipOut.putNextEntry(new ZipEntry(fileName + "/"));
+                zipOut.closeEntry();
+            }
             final File[] children = fileToZip.listFiles();
             for (final File childFile : children) {
                 zipFile(childFile, fileName + "/" + childFile.getName(), zipOut);

core-java-io/src/test/java/com/baeldung/file/FileOperationsManualTest.java

@@ -1,6 +1,7 @@
 package com.baeldung.file;
 
 import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.IOUtils;
 import org.hamcrest.CoreMatchers;
 import org.hamcrest.Matchers;
 import org.junit.Test;
@@ -17,6 +18,7 @@ import java.net.URLConnection;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import static org.junit.Assert.assertEquals;
@@ -49,7 +51,7 @@ public class FileOperationsManualTest {
 
     @Test
     public void givenFileName_whenUsingJarFile_thenFileData() throws IOException {
-        String expectedData = "BSD License";
+        String expectedData = "MIT License";
 
         Class clazz = Matchers.class;
         InputStream inputStream = clazz.getResourceAsStream("/LICENSE.txt");
@@ -78,7 +80,7 @@ public class FileOperationsManualTest {
 
         ClassLoader classLoader = getClass().getClassLoader();
         File file = new File(classLoader.getResource("fileTest.txt").getFile());
-        String data = FileUtils.readFileToString(file);
+        String data = FileUtils.readFileToString(file, "UTF-8");
 
         assertEquals(expectedData, data.trim());
     }
@@ -101,12 +103,11 @@ public class FileOperationsManualTest {
 
         Path path = Paths.get(getClass().getClassLoader().getResource("fileTest.txt").toURI());
 
-        StringBuilder data = new StringBuilder();
         Stream<String> lines = Files.lines(path);
-        lines.forEach(line -> data.append(line).append("\n"));
+        String data = lines.collect(Collectors.joining("\n"));
         lines.close();
 
-        assertEquals(expectedData, data.toString().trim());
+        assertEquals(expectedData, data.trim());
     }
 
     private String readFromInputStream(InputStream inputStream) throws IOException {
@@ -120,4 +121,14 @@ public class FileOperationsManualTest {
 
         return resultStringBuilder.toString();
     }
+    
+    @Test
+    public void givenFileName_whenUsingIOUtils_thenFileData() throws IOException {
+        String expectedData = "This is a content of the file";
+
+        FileInputStream fis = new FileInputStream("src/test/resources/fileToRead.txt");
+        String data = IOUtils.toString(fis, "UTF-8");
+        
+        assertEquals(expectedData, data.trim());
+    }
 }

core-java-io/src/test/java/com/baeldung/symlink/SymLinkExampleManualTest.java

@@ -9,7 +9,7 @@ import java.nio.file.Paths;
 
 import org.junit.Test;
 
-public class SymLinkExampleUnitTest {
+public class SymLinkExampleManualTest {
 
     @Test
     public void whenUsingFiles_thenCreateSymbolicLink() throws IOException {

core-java-io/src/test/resources/fileTest.txt

@@ -0,0 +1 @@
+Hello World from fileTest.txt!!!

core-java/README.md

@@ -151,3 +151,4 @@
 - [ClassCastException: Arrays$ArrayList cannot be cast to ArrayList](https://www.baeldung.com/java-classcastexception-arrays-arraylist)
 - [Throw Exception in Optional in Java 8](https://www.baeldung.com/java-optional-throw-exception)
 - [Add a Character to a String at a Given Position](https://www.baeldung.com/java-add-character-to-string)
+- [Synthetic Constructs in Java](https://www.baeldung.com/java-synthetic)

core-java/src/main/java/com/baeldung/doubles/SplitFloatingPointNumbers.java

@@ -0,0 +1,40 @@
+package com.baeldung.doubles;
+
+import java.math.BigDecimal;
+
+public class SplitFloatingPointNumbers {
+
+    public static void main(String[] args) {
+        
+        double doubleNumber = 24.04;
+        splitUsingFloatingTypes(doubleNumber); 
+        splitUsingString(doubleNumber);
+        splitUsingBigDecimal(doubleNumber);
+    }
+
+    private static void splitUsingFloatingTypes(double doubleNumber) {
+        System.out.println("Using Floating Point Arithmetics:");
+        int intPart = (int) doubleNumber;
+        System.out.println("Double Number: "+doubleNumber);
+        System.out.println("Integer Part: "+ intPart);
+        System.out.println("Decimal Part: "+ (doubleNumber - intPart));
+    }
+
+    private static void splitUsingString(double doubleNumber) {
+        System.out.println("Using String Operations:");
+        String doubleAsString = String.valueOf(doubleNumber);
+        int indexOfDecimal = doubleAsString.indexOf(".");
+        System.out.println("Double Number: "+doubleNumber);
+        System.out.println("Integer Part: "+ doubleAsString.substring(0, indexOfDecimal));
+        System.out.println("Decimal Part: "+ doubleAsString.substring(indexOfDecimal));
+    }
+
+    private static void splitUsingBigDecimal(double doubleNumber) {
+        System.out.println("Using BigDecimal Operations:");
+        BigDecimal bigDecimal = new BigDecimal(String.valueOf(doubleNumber));
+        int intValue = bigDecimal.intValue();
+        System.out.println("Double Number: "+bigDecimal.toPlainString());
+        System.out.println("Integer Part: "+intValue);
+        System.out.println("Decimal Part: "+bigDecimal.subtract(new BigDecimal(intValue)).toPlainString());
+    }
+}

core-java/src/main/java/com/baeldung/heapdump/HeapDump.java

@@ -0,0 +1,25 @@
+package com.baeldung.heapdump;
+
+import com.sun.management.HotSpotDiagnosticMXBean;
+
+import javax.management.MBeanServer;
+
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.nio.file.Paths;
+
+public class HeapDump {
+
+    public static void dumpHeap(String filePath, boolean live) throws IOException {
+        MBeanServer server = ManagementFactory.getPlatformMBeanServer();
+        HotSpotDiagnosticMXBean mxBean = ManagementFactory.newPlatformMXBeanProxy(
+          server, "com.sun.management:type=HotSpotDiagnostic", HotSpotDiagnosticMXBean.class);
+        mxBean.dumpHeap(filePath, live);
+    }
+
+    public static void main(String[] args) throws IOException {
+        String file = Paths.get("dump.hprof").toFile().getPath();
+
+        dumpHeap(file, true);
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/equalshashcode/Person.java

@@ -0,0 +1,9 @@
+package com.baeldung.memoryleaks.equalshashcode;
+
+public class Person {
+    public String name;
+     
+    public Person(String name) {
+        this.name = name;
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/equalshashcode/PersonOptimized.java

@@ -0,0 +1,25 @@
+package com.baeldung.memoryleaks.equalshashcode;
+
+public class PersonOptimized {
+    public String name;
+     
+    public PersonOptimized(String name) {
+        this.name = name;
+    }
+     
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) return true;
+        if (!(o instanceof PersonOptimized)) {
+            return false;
+        }
+        PersonOptimized person = (PersonOptimized) o;
+        return person.name.equals(name);
+    }
+     
+    @Override
+    public int hashCode() {
+        int result = 17;
+        result = 31 * result + name.hashCode();
+        return result;
+    }}

core-java/src/main/java/com/baeldung/memoryleaks/finalize/BulkyObject.java

@@ -0,0 +1,32 @@
+package com.baeldung.memoryleaks.finalize;
+
+import java.nio.charset.Charset;
+import java.util.Random;
+
+public class BulkyObject {
+    private String data[];
+    
+    public BulkyObject() {
+        data = new String[1000000];
+        
+        for(int i=0; i<1000000; i++) {
+            data[i] = getRandomString();
+        }
+    }
+    
+    private String getRandomString() {
+        byte[] array = new byte[1000];
+        new Random().nextBytes(array);
+        return new String(array, Charset.forName("UTF-8"));
+    }
+    
+    @Override
+    public void finalize() {
+        try {
+            Thread.sleep(100);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        System.out.println("Finalizer called");
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/finalize/BulkyObjectOptimized.java

@@ -0,0 +1,22 @@
+package com.baeldung.memoryleaks.finalize;
+
+import java.nio.charset.Charset;
+import java.util.Random;
+
+public class BulkyObjectOptimized {
+    private String data[];
+    
+    public BulkyObjectOptimized() {
+        data = new String[1000000];
+        
+        for(int i=0; i<1000000; i++) {
+            data[i] = getRandomString();
+        }
+    }
+    
+    private String getRandomString() {
+        byte[] array = new byte[1000];
+        new Random().nextBytes(array);
+        return new String(array, Charset.forName("UTF-8"));
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/innerclass/BulkyObject.java

@@ -0,0 +1,22 @@
+package com.baeldung.memoryleaks.innerclass;
+
+import java.nio.charset.Charset;
+import java.util.Random;
+
+public class BulkyObject {
+    private String data[];
+    
+    public BulkyObject() {
+        data = new String[1000000];
+        
+        for(int i=0; i<1000000; i++) {
+            data[i] = getRandomString();
+        }
+    }
+    
+    private String getRandomString() {
+        byte[] array = new byte[1000];
+        new Random().nextBytes(array);
+        return new String(array, Charset.forName("UTF-8"));
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/innerclass/InnerClassDriver.java

@@ -0,0 +1,17 @@
+package com.baeldung.memoryleaks.innerclass;
+
+public class InnerClassDriver {
+    public static InnerClassWrapper.SimpleInnerClass getSimpleInnerClassObj() {
+        return new InnerClassWrapper().new SimpleInnerClass();
+    }
+    
+    public static void main2(String[] args) {
+        InnerClassWrapper.SimpleInnerClass simpleInnerClassObj = getSimpleInnerClassObj();
+        System.out.println("Debug point");
+    }
+    
+    public static void main(String[] args) {
+        StaticNestedClassWrapper.StaticNestedClass simpleInnerClassObj = new StaticNestedClassWrapper.StaticNestedClass();
+        System.out.println("Debug point");
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/innerclass/InnerClassWrapper.java

@@ -0,0 +1,10 @@
+package com.baeldung.memoryleaks.innerclass;
+
+
+public class InnerClassWrapper {
+    private BulkyObject bulkyObject = new BulkyObject();
+    
+    public class SimpleInnerClass {
+        
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/innerclass/StaticNestedClassWrapper.java

@@ -0,0 +1,10 @@
+package com.baeldung.memoryleaks.innerclass;
+
+
+public class StaticNestedClassWrapper {
+    private BulkyObject bulkyObject = new BulkyObject();
+    
+    public static class StaticNestedClass {
+        
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/internedstrings/InternedString.java

@@ -0,0 +1,17 @@
+package com.baeldung.memoryleaks.internedstrings;
+
+public class InternedString {
+    private static final String FILEPATH = "C:\\bigstring.txt";
+    
+    public void readString() {
+        String s1 = ReadStringFromFileUtil.read(FILEPATH).intern();
+        String s2 = ReadStringFromFileUtil.read(FILEPATH).intern();
+
+        if (s1 == s2) {
+            System.out.println("Both the strings objects are same");
+        }
+        else {
+            System.out.println("Both the strings objects are different");
+        }
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/internedstrings/ReadStringFromFileUtil.java

@@ -0,0 +1,34 @@
+package com.baeldung.memoryleaks.internedstrings;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class ReadStringFromFileUtil {
+
+    public static String read(String fileName) {
+        BufferedReader br = null;
+        try {
+            br = new BufferedReader(new FileReader(fileName));
+            StringBuilder sb = new StringBuilder();
+            String line = br.readLine();
+
+            while (line != null) {
+                sb.append(line);
+                sb.append("\n");
+                line = br.readLine();
+            }
+            return sb.toString();
+        } catch (IOException e) {
+            e.printStackTrace();
+        } finally {
+            try {
+                br.close();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+        return null;
+    }
+
+}

core-java/src/main/java/com/baeldung/memoryleaks/internedstrings/StringObject.java

@@ -0,0 +1,17 @@
+package com.baeldung.memoryleaks.internedstrings;
+
+public class StringObject {
+    private static final String FILEPATH = "C:\\bigstring.txt";
+    
+    public void readString() {
+        String s1 = ReadStringFromFileUtil.read(FILEPATH);
+        String s2 = ReadStringFromFileUtil.read(FILEPATH);
+
+        if (s1 == s2) {
+            System.out.println("Both the strings objects are same");
+        }
+        else {
+            System.out.println("Both the strings objects are different");
+        }
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/staticfields/NonStaticFieldsDemo.java

@@ -0,0 +1,21 @@
+package com.baeldung.memoryleaks.staticfields;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class NonStaticFieldsDemo {
+    public List<Double> list = new ArrayList<>();
+ 
+    public void populateList() {
+        for (int i = 0; i < 10000000; i++) {
+            list.add(Math.random());
+        }
+        System.out.println("Debug Point 2");
+    }
+ 
+    public static void main(String[] args) {
+        System.out.println("Debug Point 1");
+        new NonStaticFieldsDemo().populateList();
+        System.out.println("Debug Point 3");
+    }
+}

core-java/src/main/java/com/baeldung/memoryleaks/staticfields/StaticFieldsDemo.java

@@ -0,0 +1,21 @@
+package com.baeldung.memoryleaks.staticfields;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class StaticFieldsDemo {
+    public static List<Double> list = new ArrayList<>();
+ 
+    public void populateList() {
+        for (int i = 0; i < 10000000; i++) {
+            list.add(Math.random());
+        }
+        System.out.println("Debug Point 2");
+    }
+ 
+    public static void main(String[] args) {
+        System.out.println("Debug Point 1");
+        new StaticFieldsDemo().populateList();
+        System.out.println("Debug Point 3");
+    }
+}

core-java/src/main/java/com/baeldung/nth/root/calculator/NthRootCalculator.java

@@ -0,0 +1,8 @@
+package com.baeldung.nth.root.calculator;
+
+public class NthRootCalculator
+{
+    public Double calculate(Double base, Double n) {
+        return Math.pow(Math.E, Math.log(base)/n);
+    }
+}

core-java/src/main/java/com/baeldung/nth/root/main/Main.java

@@ -0,0 +1,13 @@
+package com.baeldung.nth.root.main;
+
+import com.baeldung.nth.root.calculator.NthRootCalculator;
+
+public class Main {
+    public static void main(String[] args) {
+        NthRootCalculator calculator = new NthRootCalculator();
+        Double base = Double.parseDouble(args[0]);
+        Double n = Double.parseDouble(args[1]);
+        Double result = calculator.calculate(base, n);
+        System.out.println("The " + n + " root of " + base + " equals to " + result + ".");
+    }
+}

core-java/src/main/java/com/baeldung/passwordhashing/PBKDF2Hasher.java

@@ -0,0 +1,149 @@
+package com.baeldung.passwordhashing;
+
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.KeySpec;
+import java.util.Arrays;
+import java.util.Base64;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+
+/**
+ * Hash passwords for storage, and test passwords against password tokens.
+ *
+ * Instances of this class can be used concurrently by multiple threads.
+ *
+ * @author erickson
+ * @see <a href="http://stackoverflow.com/a/2861125/3474">StackOverflow</a>
+ */
+public final class PBKDF2Hasher
+{
+
+  /**
+   * Each token produced by this class uses this identifier as a prefix.
+   */
+  public static final String ID = "$31$";
+
+  /**
+   * The minimum recommended cost, used by default
+   */
+  public static final int DEFAULT_COST = 16;
+
+  private static final String ALGORITHM = "PBKDF2WithHmacSHA1";
+
+  private static final int SIZE = 128;
+
+  private static final Pattern layout = Pattern.compile("\\$31\\$(\\d\\d?)\\$(.{43})");
+
+  private final SecureRandom random;
+
+  private final int cost;
+
+  public PBKDF2Hasher()
+  {
+    this(DEFAULT_COST);
+  }
+
+  /**
+   * Create a password manager with a specified cost
+   *
+   * @param cost the exponential computational cost of hashing a password, 0 to 30
+   */
+  public PBKDF2Hasher(int cost)
+  {
+    iterations(cost); /* Validate cost */
+    this.cost = cost;
+    this.random = new SecureRandom();
+  }
+
+  private static int iterations(int cost)
+  {
+    if ((cost < 0) || (cost > 30))
+      throw new IllegalArgumentException("cost: " + cost);
+    return 1 << cost;
+  }
+
+  /**
+   * Hash a password for storage.
+   *
+   * @return a secure authentication token to be stored for later authentication
+   */
+  public String hash(char[] password)
+  {
+    byte[] salt = new byte[SIZE / 8];
+    random.nextBytes(salt);
+    byte[] dk = pbkdf2(password, salt, 1 << cost);
+    byte[] hash = new byte[salt.length + dk.length];
+    System.arraycopy(salt, 0, hash, 0, salt.length);
+    System.arraycopy(dk, 0, hash, salt.length, dk.length);
+    Base64.Encoder enc = Base64.getUrlEncoder().withoutPadding();
+    return ID + cost + '$' + enc.encodeToString(hash);
+  }
+
+  /**
+   * Authenticate with a password and a stored password token.
+   *
+   * @return true if the password and token match
+   */
+  public boolean checkPassword(char[] password, String token)
+  {
+    Matcher m = layout.matcher(token);
+    if (!m.matches())
+      throw new IllegalArgumentException("Invalid token format");
+    int iterations = iterations(Integer.parseInt(m.group(1)));
+    byte[] hash = Base64.getUrlDecoder().decode(m.group(2));
+    byte[] salt = Arrays.copyOfRange(hash, 0, SIZE / 8);
+    byte[] check = pbkdf2(password, salt, iterations);
+    int zero = 0;
+    for (int idx = 0; idx < check.length; ++idx)
+      zero |= hash[salt.length + idx] ^ check[idx];
+    return zero == 0;
+  }
+
+  private static byte[] pbkdf2(char[] password, byte[] salt, int iterations)
+  {
+    KeySpec spec = new PBEKeySpec(password, salt, iterations, SIZE);
+    try {
+      SecretKeyFactory f = SecretKeyFactory.getInstance(ALGORITHM);
+      return f.generateSecret(spec).getEncoded();
+    }
+    catch (NoSuchAlgorithmException ex) {
+      throw new IllegalStateException("Missing algorithm: " + ALGORITHM, ex);
+    }
+    catch (InvalidKeySpecException ex) {
+      throw new IllegalStateException("Invalid SecretKeyFactory", ex);
+    }
+  }
+
+  /**
+   * Hash a password in an immutable {@code String}.
+   *
+   * <p>Passwords should be stored in a {@code char[]} so that it can be filled
+   * with zeros after use instead of lingering on the heap and elsewhere.
+   *
+   * @deprecated Use {@link #hash(char[])} instead
+   */
+  @Deprecated
+  public String hash(String password)
+  {
+    return hash(password.toCharArray());
+  }
+
+  /**
+   * Authenticate with a password in an immutable {@code String} and a stored
+   * password token.
+   *
+   * @deprecated Use {@link #checkPassword(char[],String)} instead.
+   * @see #hash(String)
+   */
+  @Deprecated
+  public boolean checkPassword(String password, String token)
+  {
+    return checkPassword(password.toCharArray(), token);
+  }
+
+}

core-java/src/main/java/com/baeldung/passwordhashing/SHA512Hasher.java

@@ -0,0 +1,35 @@
+package com.baeldung.passwordhashing;
+
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+
+/** A really simple SHA_512 Encryption example.
+ *
+ */
+public class SHA512Hasher {
+
+  public String hash(String passwordToHash, byte[] salt){
+    String generatedPassword = null;
+    try {
+      MessageDigest md = MessageDigest.getInstance("SHA-512");
+      md.update(salt);
+      byte[] bytes = md.digest(passwordToHash.getBytes(StandardCharsets.UTF_8));
+      StringBuilder sb = new StringBuilder();
+      for(int i=0; i< bytes.length ;i++){
+        sb.append(Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1));
+      }
+      generatedPassword = sb.toString();
+    }
+    catch (NoSuchAlgorithmException e){
+      e.printStackTrace();
+    }
+    return generatedPassword;
+  }
+
+  public boolean checkPassword(String hash, String attempt, byte[] salt){
+    String generatedHash = hash(attempt, salt);
+    return hash.equals(generatedHash);
+  }
+}

core-java/src/main/java/com/baeldung/passwordhashing/SimplePBKDF2Hasher.java

@@ -0,0 +1,18 @@
+package com.baeldung.passwordhashing;
+
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+import java.security.spec.KeySpec;
+
+/** A really simple SimplePBKDF2 Encryption example.
+ *
+ */
+public class SimplePBKDF2Hasher {
+
+  public static String hashSimple(String password, byte[] salt) throws Exception{
+    KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, 65536, 128);
+    SecretKeyFactory f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
+    byte[] hash = f.generateSecret(spec).getEncoded();
+    return String.valueOf(hash);
+  }
+}

core-java/src/main/java/com/baeldung/switchstatement/SwitchStatement.java

@@ -0,0 +1,70 @@
+package com.baeldung.switchstatement;
+
+public class SwitchStatement {
+
+    public String exampleOfIF(String animal) {
+
+        String result;
+
+        if (animal.equals("DOG") || animal.equals("CAT")) {
+            result = "domestic animal";
+        } else if (animal.equals("TIGER")) {
+            result = "wild animal";
+        } else {
+            result = "unknown animal";
+        }
+        return result;
+    }
+
+    public String exampleOfSwitch(String animal) {
+
+        String result;
+
+        switch (animal) {
+        case "DOG":
+        case "CAT":
+            result = "domestic animal";
+            break;
+        case "TIGER":
+            result = "wild animal";
+            break;
+        default:
+            result = "unknown animal";
+            break;
+        }
+        return result;
+    }
+
+    public String forgetBreakInSwitch(String animal) {
+
+        String result;
+
+        switch (animal) {
+
+        case "DOG":
+            System.out.println("domestic animal");
+            result = "domestic animal";
+
+        default:
+            System.out.println("unknown animal");
+            result = "unknown animal";
+
+        }
+        return result;
+    }
+
+    public String constantCaseValue(String animal) {
+
+        String result = "";
+
+        final String dog = "DOG";
+
+        switch (animal) {
+
+        case dog:
+            result = "domestic animal";
+        }
+        return result;
+    }
+
+}

core-java/src/main/java/com/baeldung/zoneddatetime/OffsetDateTimeExample.java

@@ -0,0 +1,13 @@
+package com.baeldung.zoneddatetime;
+
+import java.time.OffsetDateTime;
+import java.time.ZoneOffset;
+
+public class OffsetDateTimeExample {
+
+    public OffsetDateTime getCurrentTimeByZoneOffset(String offset) {
+        ZoneOffset zoneOffSet= ZoneOffset.of(offset);
+        OffsetDateTime date = OffsetDateTime.now(zoneOffSet);
+        return date;
+    }
+}

core-java/src/main/java/com/baeldung/zoneddatetime/OffsetTimeExample.java

@@ -0,0 +1,13 @@
+package com.baeldung.zoneddatetime;
+
+import java.time.OffsetTime;
+import java.time.ZoneOffset;
+
+public class OffsetTimeExample {
+
+    public OffsetTime getCurrentTimeByZoneOffset(String offset) {
+        ZoneOffset zoneOffSet = ZoneOffset.of(offset);
+        OffsetTime time = OffsetTime.now(zoneOffSet);
+        return time;
+    }
+}

core-java/src/main/java/com/baeldung/zoneddatetime/ZoneDateTimeExample.java

@@ -0,0 +1,21 @@
+package com.baeldung.zoneddatetime;
+
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+
+public class ZoneDateTimeExample {
+
+    public ZonedDateTime getCurrentTimeByZoneId(String region) {
+        ZoneId zone = ZoneId.of(region);
+        ZonedDateTime date = ZonedDateTime.now(zone);
+        return date;
+    }
+
+    public ZonedDateTime convertZonedDateTime(ZonedDateTime sourceDate, String destZone) {
+
+        ZoneId destZoneId = ZoneId.of(destZone);
+        ZonedDateTime destDate = sourceDate.withZoneSameInstant(destZoneId);
+
+        return destDate;
+    }
+}

core-java/src/test/java/com/baeldung/memoryleaks/equalshashcode/PersonMemoryLeakUnitTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.memoryleaks.equalshashcode;
+
+import static org.junit.Assert.assertTrue;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class PersonMemoryLeakUnitTest {
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenMap_whenEqualsAndHashCodeNotOverridden_thenMemoryLeak() {
+        Map<Person, Integer> map = new HashMap<Person, Integer>();
+        for(int i=0; i<10000000; i++) {
+            map.put(new Person("jon"), 1);
+        }
+        assertTrue(map.size() > 1);
+        System.out.print("Debug Point - VisuaLVM");
+    }
+    
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenMap_whenEqualsAndHashCodeOverridden_thenNoMemoryLeak() {
+        Map<PersonOptimized, Integer> map = new HashMap<PersonOptimized, Integer>();
+        for(int i=0; i<10000; i++) {
+            map.put(new PersonOptimized("jon"), 1);
+        }
+        assertTrue(map.size() == 1);
+        System.out.print("Debug Point - VisuaLVM");
+    }
+}

core-java/src/test/java/com/baeldung/memoryleaks/finalize/FinalizeMemoryLeakUnitTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.memoryleaks.finalize;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class FinalizeMemoryLeakUnitTest {
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenObjectWithFinalizer_whenCreatingAndDestroyingThisObject_thenMemoryLeak() {
+        BulkyObject[] stock = new BulkyObject[100000];
+        
+        for(int i=0; i<100000; i++) {
+            stock[i] = new BulkyObject();
+        }
+        System.out.print("Debug Point - VisuaLVM");
+    }
+    
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenObjectWithoutFinalizer_whenCreatingAndDestroyingThisObject_thenNoMemoryLeak() {
+        BulkyObjectOptimized[] stock = new BulkyObjectOptimized[100000];
+        
+        for(int i=0; i<100000; i++) {
+            stock[i] = new BulkyObjectOptimized();
+        }
+        System.out.print("Debug Point - VisuaLVM");
+    }
+}

core-java/src/test/java/com/baeldung/memoryleaks/innerclass/StaticInnerClassMemoryLeakUnitTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.memoryleaks.innerclass;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class StaticInnerClassMemoryLeakUnitTest {
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenUsingInnerClass_whenInitializingInnerClass_thenInnerClassHoldsReferenceOfOuterObject() {
+        InnerClassWrapper.SimpleInnerClass simpleInnerClassObj = new InnerClassWrapper().new SimpleInnerClass();
+        System.out.print("Debug Point - VisuaLVM");
+    }
+    
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenUsingStaticNestedClass_whenInitializingInnerClass_thenStaticNestedClassDoesntReferenceOuterObject() {
+        StaticNestedClassWrapper.StaticNestedClass staticNestedClassObj = new StaticNestedClassWrapper.StaticNestedClass();
+        System.out.print("Debug Point - VisuaLVM");
+    }
+}

core-java/src/test/java/com/baeldung/memoryleaks/internedstrings/StringInternMemoryLeakUnitTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.memoryleaks.internedstrings;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class StringInternMemoryLeakUnitTest {
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenJava6OrBelow_whenInterningLargeStrings_thenPermgenIncreases() {
+        new InternedString().readString();
+        System.out.print("Debug Point - VisuaLVM");
+    }
+    
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenJava6OrBelow_whenNotInterningLargeStrings_thenPermgenDoesntIncrease() {
+        new StringObject().readString();
+        System.out.print("Debug Point - VisuaLVM");
+    }
+}

core-java/src/test/java/com/baeldung/memoryleaks/staticfields/NonStaticFieldsMemoryLeakUnitTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.memoryleaks.staticfields;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class NonStaticFieldsMemoryLeakUnitTest {
+    public List<Double> list = new ArrayList<>();
+ 
+    public void populateList() {
+        for (int i = 0; i < 10000000; i++) {
+            list.add(Math.random());
+        }
+        System.out.println("Debug Point 2");
+    }
+ 
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenNonStaticLargeList_whenPopulatingList_thenListGarbageCollected() {
+        System.out.println("Debug Point 1");
+        new NonStaticFieldsMemoryLeakUnitTest().populateList();
+        System.out.println("Debug Point 3");
+    }
+}

core-java/src/test/java/com/baeldung/memoryleaks/staticfields/StaticFieldsMemoryLeakUnitTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.memoryleaks.staticfields;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class StaticFieldsMemoryLeakUnitTest {
+    public static List<Double> list = new ArrayList<>();
+ 
+    public void populateList() {
+        for (int i = 0; i < 10000000; i++) {
+            list.add(Math.random());
+        }
+        System.out.println("Debug Point 2");
+    }
+ 
+    @Test
+    @Ignore // Test deliberately ignored as memory leak tests consume lots of resources
+    public void givenStaticLargeList_whenPopulatingList_thenListIsNotGarbageCollected() {
+        System.out.println("Debug Point 1");
+        new StaticFieldsDemo().populateList();
+        System.out.println("Debug Point 3");
+    }
+}

core-java/src/test/java/com/baeldung/nth/root/calculator/NthRootCalculatorUnitTest.java

@@ -0,0 +1,21 @@
+package com.baeldung.nth.root.calculator;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.InjectMocks;
+import org.mockito.runners.MockitoJUnitRunner;
+
+import static org.junit.Assert.assertEquals;
+
+@RunWith(MockitoJUnitRunner.class)
+public class NthRootCalculatorUnitTest {
+
+    @InjectMocks
+    private NthRootCalculator nthRootCalculator;
+
+    @Test
+    public void giventThatTheBaseIs125_andTheExpIs3_whenCalculateIsCalled_thenTheResultIsTheCorrectOne() {
+       Double result = nthRootCalculator.calculate(125.0, 3.0);
+       assertEquals(result, (Double) 5.0d);
+    }
+}

core-java/src/test/java/com/baeldung/nth/root/main/MainUnitTest.java

@@ -0,0 +1,34 @@
+package com.baeldung.nth.root.main;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InjectMocks;
+import static org.junit.Assert.assertEquals;
+
+public class MainUnitTest {
+    @InjectMocks
+    private Main main;
+
+    private final ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+    private final PrintStream originalOut = System.out;
+
+    @Before
+    public void setUpStreams() {
+        System.setOut(new PrintStream(outContent));
+    }
+
+    @After
+    public void restoreStreams() {
+        System.setOut(originalOut);
+    }
+
+    @Test
+    public void givenThatTheBaseIs125_andTheExpIs3_whenMainIsCalled_thenTheCorrectResultIsPrinted() {
+        main.main(new String[]{"125.0", "3.0"});
+        assertEquals("The 3.0 root of 125.0 equals to 5.0.\n", outContent.toString().replaceAll("\r", ""));
+    }
+}

core-java/src/test/java/com/baeldung/passwordhashing/PBKDF2HasherUnitTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.passwordhashing;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+
+public class PBKDF2HasherUnitTest {
+
+  private PBKDF2Hasher mPBKDF2Hasher;
+
+  @Before
+  public void setUp() throws Exception {
+    mPBKDF2Hasher = new PBKDF2Hasher();
+  }
+
+  @Test
+  public void givenCorrectMessageAndHash_whenAuthenticated_checkAuthenticationSucceeds() throws Exception {
+    String message1 = "password123";
+
+    String hash1 = mPBKDF2Hasher.hash(message1.toCharArray());
+
+    assertTrue(mPBKDF2Hasher.checkPassword(message1.toCharArray(), hash1));
+
+  }
+
+  @Test
+  public void givenWrongMessage_whenAuthenticated_checkAuthenticationFails() throws Exception {
+    String message1 = "password123";
+
+    String hash1 = mPBKDF2Hasher.hash(message1.toCharArray());
+
+    String wrongPasswordAttempt = "IamWrong";
+
+    assertFalse(mPBKDF2Hasher.checkPassword(wrongPasswordAttempt.toCharArray(), hash1));
+
+  }
+
+
+}

core-java/src/test/java/com/baeldung/passwordhashing/SHA512HasherUnitTest.java

@@ -0,0 +1,70 @@
+package com.baeldung.passwordhashing;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.security.SecureRandom;
+
+import static org.junit.Assert.*;
+
+/**
+ * Created by PhysicsSam on 06-Sep-18.
+ */
+public class SHA512HasherUnitTest {
+
+  private SHA512Hasher hasher;
+  private SecureRandom secureRandom;
+
+  @Before
+  public void setUp() throws Exception {
+    hasher = new SHA512Hasher();
+    secureRandom = new SecureRandom();
+  }
+
+  @Test
+  public void givenSamePasswordAndSalt_whenHashed_checkResultingHashesAreEqual() throws Exception {
+
+    byte[] salt = new byte[16];
+    secureRandom.nextBytes(salt);
+
+    String hash1 = hasher.hash("password", salt);
+    String hash2 = hasher.hash("password", salt);
+
+    assertEquals(hash1, hash2);
+
+  }
+
+  @Test
+  public void givenSamePasswordAndDifferentSalt_whenHashed_checkResultingHashesNotEqual() throws Exception {
+
+    byte[] salt = new byte[16];
+    secureRandom.nextBytes(salt);
+    String hash1 = hasher.hash("password", salt);
+    //generate a second salt
+    byte[] secondSalt = new byte[16];
+    String hash2 = hasher.hash("password", secondSalt);
+
+    assertNotEquals(hash1, hash2);
+
+  }
+
+  @Test
+  public void givenPredefinedHash_whenCorrectAttemptGiven_checkAuthenticationSucceeds() throws Exception {
+    byte[] salt = new byte[16];
+    secureRandom.nextBytes(salt);
+
+    String originalHash = hasher.hash("password123", salt);
+
+    assertTrue(hasher.checkPassword(originalHash, "password123", salt));
+  }
+
+  @Test
+  public void givenPredefinedHash_whenIncorrectAttemptGiven_checkAuthenticationFails() throws Exception {
+    byte[] salt = new byte[16];
+    secureRandom.nextBytes(salt);
+
+    String originalHash = hasher.hash("password123", salt);
+
+    assertFalse(hasher.checkPassword(originalHash, "password124", salt));
+  }
+}

core-java/src/test/java/com/baeldung/switchstatement/SwitchStatementUnitTest.java

@@ -0,0 +1,38 @@
+package com.baeldung.switchstatement;
+
+import org.junit.Test;
+
+import org.junit.Assert;
+
+public class SwitchStatementUnitTest {
+    private SwitchStatement s = new SwitchStatement();
+
+    
+    @Test
+    public void whenDog_thenDomesticAnimal() {
+        
+        String animal = "DOG";
+        Assert.assertEquals("domestic animal", s.exampleOfSwitch(animal));
+    }
+    
+    @Test
+    public void whenNoBreaks_thenGoThroughBlocks() {
+        String animal = "DOG";
+        Assert.assertEquals("unknown animal", s.forgetBreakInSwitch(animal));
+    }
+    
+    @Test(expected=NullPointerException.class)
+    public void whenSwitchAgumentIsNull_thenNullPointerException() {
+        String animal = null;
+        Assert.assertEquals("domestic animal", s.exampleOfSwitch(animal));
+    }
+    
+       
+    @Test
+    public void whenCompareStrings_thenByEqual() {
+        String animal = new String("DOG");
+        Assert.assertEquals("domestic animal", s.exampleOfSwitch(animal));
+    }
+    
+  
+}

core-java/src/test/java/com/baeldung/ternaryoperator/TernaryOperatorUnitTest.java

@@ -0,0 +1,43 @@
+package com.baeldung.ternaryoperator;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
+
+public class TernaryOperatorUnitTest {
+
+    @Test
+    public void givenACondition_whenUsingTernaryOperator_thenItEvaluatesConditionAndReturnsAValue() {
+        int number = 10;
+        String msg = number > 10 ? "Number is greater than 10" : "Number is less than or equal to 10";
+
+        assertThat(msg).isEqualTo("Number is less than or equal to 10");
+    }
+
+    @Test
+    public void givenATrueCondition_whenUsingTernaryOperator_thenOnlyExpression1IsEvaluated() {
+        int exp1 = 0, exp2 = 0;
+        int result = 12 > 10 ? ++exp1 : ++exp2;
+
+        assertThat(exp1).isEqualTo(1);
+        assertThat(exp2).isEqualTo(0);
+        assertThat(result).isEqualTo(1);
+    }
+
+    @Test
+    public void givenAFalseCondition_whenUsingTernaryOperator_thenOnlyExpression2IsEvaluated() {
+        int exp1 = 0, exp2 = 0;
+        int result = 8 > 10 ? ++exp1 : ++exp2;
+
+        assertThat(exp1).isEqualTo(0);
+        assertThat(exp2).isEqualTo(1);
+        assertThat(result).isEqualTo(1);
+    }
+
+    @Test
+    public void givenANestedCondition_whenUsingTernaryOperator_thenCorrectValueIsReturned() {
+        int number = 6;
+        String msg = number > 10 ? "Number is greater than 10" : number > 5 ? "Number is greater than 5" : "Number is less than or equal to 5";
+
+        assertThat(msg).isEqualTo("Number is greater than 5");
+    }
+}