Merge branch 'master' into javabeanconstraints

README.md

@@ -2,41 +2,22 @@
 The "REST with Spring" Classes
 ==============================
 
-Here's the Master Class of REST With Spring (price changes permanently next Friday): <br/>
+Here's the Master Class of REST With Spring (along with the newly announced Boot 2 material): <br/>
-**[>> THE REST WITH SPRING MASTER CLASS](http://www.baeldung.com/rest-with-spring-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=rws#master-class)**
+**[>> THE REST WITH SPRING - MASTER CLASS](http://www.baeldung.com/rest-with-spring-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=rws#master-class)**
 
 And here's the Master Class of Learn Spring Security: <br/>
-**[>> LEARN SPRING SECURITY MASTER CLASS](http://www.baeldung.com/learn-spring-security-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=lss#master-class)**
+**[>> LEARN SPRING SECURITY - MASTER CLASS](http://www.baeldung.com/learn-spring-security-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=lss#master-class)**
 
 
 
-Spring Tutorials
+Java and Spring Tutorials
 ================
 
-This project is **a collection of small and focused tutorials** each covering a single and well defined area of development. 
+This project is **a collection of small and focused tutorials** - each covering a single and well defined area of development in the Java ecosystem. 
-Most of the tutorial projects are focused on the `Spring Framework` (and `Spring Security`).  
+A strong focus of these is, of course, the Spring Framework - Spring, Spring Boot and Spring Securiyt. 
 In additional to Spring, the following technologies are in focus: `core Java`, `Jackson`, `HttpClient`, `Guava`. 
 
+
 Building the project
 ====================
 To do the full build, do: `mvn install -Pdefault -Dgib.enabled=false`
-
-
-Working with the code in Eclipse
-================================
-Any IDE can be used to work with the projects, but if you're using Eclipse, consider the following. 
-
-- import the included **formatter** in Eclipse: 
-`https://github.com/eugenp/tutorials/tree/master/eclipse`
-
-
-CI - Jenkins
-================================
-This tutorials project is being built **[>> HERE](https://rest-security.ci.cloudbees.com/job/tutorials-unit/)**
-
-### Relevant Articles: 
-================================
-
-- [Apache Maven Standard Directory Layout](http://www.baeldung.com/maven-directory-structure)
-- [Apache Maven Tutorial](http://www.baeldung.com/maven)
-- [Designing a User Friendly Java Library](http://www.baeldung.com/design-a-user-friendly-java-library)

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/src/main/java/com/baeldung/algorithms/kthlargest/FindKthLargest.java

@@ -98,7 +98,7 @@ public class FindKthLargest {
 
     private int randomPartition(Integer arr[], int left, int right) {
         int n = right - left + 1;
-        int pivot = (int) (Math.random()) % n;
+        int pivot = (int) (Math.random() * n);
         swap(arr, left + pivot, right);
         return partition(arr, left, right);
     }

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());
+    }
+}

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>
+        <asciidoctor-maven-plugin.version>1.5.6</asciidoctor-maven-plugin.version>
-        <asciidoctorj.version>1.5.4</asciidoctorj.version>
+        <asciidoctorj.version>1.5.6</asciidoctorj.version>
-        <asciidoctorj-pdf.src.version>1.5.0-alpha.11</asciidoctorj-pdf.src.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() {

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/java8/Java8SortUnitTest.java

@@ -1,16 +1,18 @@
 package com.baeldung.java8;
 
-import com.baeldung.java8.entity.Human;
+import static org.hamcrest.Matchers.equalTo;
-import com.google.common.collect.Lists;
-import com.google.common.primitives.Ints;
-import org.junit.Assert;
-import org.junit.Test;
 
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
+import java.util.stream.Collectors;
 
-import static org.hamcrest.Matchers.equalTo;
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.baeldung.java8.entity.Human;
+import com.google.common.collect.Lists;
+import com.google.common.primitives.Ints;
 
 public class Java8SortUnitTest {
 
@@ -112,4 +114,21 @@ public class Java8SortUnitTest {
         Assert.assertThat(humans.get(0), equalTo(new Human("Jack", 12)));
     }
     
+    @Test
+    public final void givenStreamNaturalOrdering_whenSortingEntitiesByName_thenCorrectlySorted() {
+        final List<String> letters = Lists.newArrayList("B", "A", "C");
+        
+        final List<String> sortedLetters = letters.stream().sorted().collect(Collectors.toList());
+        Assert.assertThat(sortedLetters.get(0), equalTo("A"));
+    }
+
+    @Test
+    public final void givenStreamCustomOrdering_whenSortingEntitiesByName_thenCorrectlySorted() {
+        
+        final List<Human> humans = Lists.newArrayList(new Human("Sarah", 10), new Human("Jack", 12));
+        final Comparator<Human> nameComparator = (h1, h2) -> h1.getName().compareTo(h2.getName());
+        
+        final List<Human> sortedHumans = humans.stream().sorted(nameComparator).collect(Collectors.toList());
+        Assert.assertThat(sortedHumans.get(0), equalTo(new Human("Jack", 12)));
+    }
 }

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 +63,17 @@
             <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>
+        <dependency>
+            <groupId>one.util</groupId>
+            <artifactId>streamex</artifactId>
+            <version>0.6.5</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/java_8/MergeMaps.java

@@ -0,0 +1,105 @@
+package com.baeldung.map.java_8;
+
+import com.baeldung.sort.Employee;
+import one.util.streamex.EntryStream;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class MergeMaps {
+
+    private static Map<String, Employee> map1 = new HashMap<>();
+    private static Map<String, Employee> map2 = new HashMap<>();
+
+    public static void main(String[] args) {
+
+        initialize();
+
+        mergeFunction();
+
+        streamConcat();
+
+        streamOf();
+
+        streamEx();
+
+        streamMerge();
+    }
+
+    private static void streamMerge() {
+
+        Map<String, Employee> map3 = map2.entrySet()
+                .stream()
+                .collect(
+                        Collectors.toMap(
+                                Map.Entry::getKey,
+                                Map.Entry::getValue,
+                                (v1, v2) -> new Employee(v1.getId(), v2.getName()),
+                                () -> new HashMap<>(map1)
+                        )
+                );
+
+        System.out.println(map3);
+    }
+
+    private static void streamEx() {
+        Map<String, Employee> map3 = EntryStream.of(map1)
+                .append(EntryStream.of(map2))
+                .toMap((e1, e2) -> e1);
+
+        System.out.println(map3);
+
+    }
+
+    private static void streamOf() {
+        Map<String, Employee> map3 = Stream.of(map1, map2)
+                .flatMap(map -> map.entrySet().stream())
+                .collect(
+                        Collectors.toMap(
+                                Map.Entry::getKey,
+                                Map.Entry::getValue,
+                                (v1, v2) -> new Employee(v1.getId(), v2.getName())
+                        )
+                );
+
+        map3.entrySet().forEach(System.out::println);
+    }
+
+    private static void streamConcat() {
+        Map<String, Employee> result = Stream.concat(map1.entrySet().stream(), map2.entrySet().stream()).collect(Collectors.toMap(
+                Map.Entry::getKey,
+                Map.Entry::getValue,
+                (value1, value2) -> new Employee(value2.getId(), value1.getName())
+        ));
+
+        result.entrySet().forEach(System.out::println);
+    }
+
+    private static void mergeFunction() {
+        Map<String, Employee> map3 = new HashMap<>(map1);
+
+        map2.forEach(
+                (key, value) -> map3.merge(key, value, (v1, v2) ->
+                        new Employee(v1.getId(), v2.getName()))
+        );
+
+        map3.entrySet().forEach(System.out::println);
+    }
+
+
+    private static void initialize() {
+        Employee employee1 = new Employee(1L, "Henry");
+        map1.put(employee1.getName(), employee1);
+        Employee employee2 = new Employee(22L, "Annie");
+        map1.put(employee2.getName(), employee2);
+        Employee employee3 = new Employee(8L, "John");
+        map1.put(employee3.getName(), employee3);
+
+        Employee employee4 = new Employee(2L, "George");
+        map2.put(employee4.getName(), employee4);
+        Employee employee5 = new Employee(3L, "Henry");
+        map2.put(employee5.getName(), employee5);
+    }
+
+}

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/java/map/KeyCheckTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.java.map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.commons.collections4.MultiMap;
+import org.apache.commons.collections4.MultiMapUtils;
+import org.apache.commons.collections4.MultiValuedMap;
+import org.apache.commons.collections4.map.MultiValueMap;
+import org.apache.commons.collections4.multimap.ArrayListValuedHashMap;
+import org.apache.commons.collections4.multimap.HashSetValuedHashMap;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.LinkedHashMultimap;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.TreeMultimap;
+
+
+public class KeyCheckTest {
+
+    @Test
+    public void whenKeyIsPresent_thenContainsKeyReturnsTrue() {
+        Map<String, String> map = Collections.singletonMap("key", "value");
+
+        assertTrue(map.containsKey("key"));
+        assertFalse(map.containsKey("missing"));
+    }
+
+    @Test
+    public void whenKeyHasNullValue_thenGetStillWorks() {
+        Map<String, String> map = Collections.singletonMap("nothing", null);
+
+        assertTrue(map.containsKey("nothing"));
+        assertNull(map.get("nothing"));
+    }
+}

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/src/test/java/com/baeldung/file/FileOperationsManualTest.java

@@ -18,6 +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;
@@ -50,7 +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");
@@ -79,7 +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());
     }
@@ -102,12 +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 {

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

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

core-java/README.md

@@ -25,7 +25,6 @@
 - [The Traveling Salesman Problem in Java](http://www.baeldung.com/java-simulated-annealing-for-traveling-salesman)
 - [How to Create an Executable JAR with Maven](http://www.baeldung.com/executable-jar-with-maven)
 - [How to Design a Genetic Algorithm in Java](http://www.baeldung.com/java-genetic-algorithm)
-- [Spring Security – Cache Control Headers](http://www.baeldung.com/spring-security-cache-control-headers)
 - [Basic Introduction to JMX](http://www.baeldung.com/java-management-extensions)
 - [AWS Lambda With Java](http://www.baeldung.com/java-aws-lambda)
 - [Introduction to Nashorn](http://www.baeldung.com/java-nashorn)
@@ -37,7 +36,6 @@
 - [Guide to sun.misc.Unsafe](http://www.baeldung.com/java-unsafe)
 - [How to Perform a Simple HTTP Request in Java](http://www.baeldung.com/java-http-request)
 - [Call Methods at Runtime Using Java Reflection](http://www.baeldung.com/java-method-reflection)
-- [Guide to UUID in JAVA](http://www.baeldung.com/guide-to-uuid-in-java)
 - [How to Add a Single Element to a Stream](http://www.baeldung.com/java-stream-append-prepend)
 - [Iterating Over Enum Values in Java](http://www.baeldung.com/java-enum-iteration)
 - [Kotlin Java Interoperability](http://www.baeldung.com/kotlin-java-interoperability)
@@ -151,3 +149,4 @@
 - [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/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/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/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/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");
+    }
+}

core-kotlin/README.md

@@ -34,3 +34,6 @@
 - [Kotlin Constructors](https://www.baeldung.com/kotlin-constructors)
 - [Creational Design Patterns in Kotlin: Builder](https://www.baeldung.com/kotlin-builder-pattern)
 - [Kotlin Nested and Inner Classes](https://www.baeldung.com/kotlin-inner-classes)
+- [Kotlin with Ktor](https://www.baeldung.com/kotlin-ktor)
+- [Fuel HTTP Library with Kotlin](https://www.baeldung.com/kotlin-fuel)
+- [Introduction to Kovenant Library for Kotlin](https://www.baeldung.com/kotlin-kovenant)

core-kotlin/src/test/kotlin/com/baeldung/kotlin/StructuralJumpUnitTest.kt

@@ -0,0 +1,121 @@
+package com.baeldung.kotlin
+
+import org.junit.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+
+class StructuralJumpUnitTest {
+
+    @Test
+    fun givenLoop_whenBreak_thenComplete() {
+        var value = ""
+        for (i in "hello_world") {
+            if (i == '_')
+                break
+            value += i.toString()
+        }
+        assertEquals("hello", value)
+    }
+    @Test
+    fun givenLoop_whenBreakWithLabel_thenComplete() {
+        var value = ""
+        outer_loop@ for (i in 'a'..'d') {
+            for (j in 1..3) {
+                value += "" + i + j
+                if (i == 'b' && j == 1)
+                    break@outer_loop
+            }
+        }
+        assertEquals("a1a2a3b1", value)
+    }
+
+    @Test
+    fun givenLoop_whenContinue_thenComplete() {
+        var result = ""
+        for (i in "hello_world") {
+            if (i == '_')
+                continue
+            result += i
+        }
+        assertEquals("helloworld", result)
+    }
+    @Test
+    fun givenLoop_whenContinueWithLabel_thenComplete() {
+        var result = ""
+        outer_loop@ for (i in 'a'..'c') {
+            for (j in 1..3) {
+                if (i == 'b')
+                    continue@outer_loop
+                result += "" + i + j
+            }
+        }
+        assertEquals("a1a2a3c1c2c3", result)
+    }
+
+    @Test
+    fun givenLambda_whenReturn_thenComplete() {
+        var result = returnInLambda();
+        assertEquals("hello", result)
+    }
+
+    private fun returnInLambda(): String {
+        var result = ""
+        "hello_world".forEach {
+            // non-local return directly to the caller
+            if (it == '_') return result
+            result += it.toString()
+        }
+        //this line won't be reached
+        return result;
+    }
+
+    @Test
+    fun givenLambda_whenReturnWithExplicitLabel_thenComplete() {
+        var result = ""
+        "hello_world".forEach lit@{
+            if (it == '_') {
+                // local return to the caller of the lambda, i.e. the forEach loop
+                return@lit
+            }
+            result += it.toString()
+        }
+        assertEquals("helloworld", result)
+    }
+
+    @Test
+    fun givenLambda_whenReturnWithImplicitLabel_thenComplete() {
+        var result = ""
+        "hello_world".forEach {
+            if (it == '_') {
+                // local return to the caller of the lambda, i.e. the forEach loop
+                return@forEach
+            }
+            result += it.toString()
+        }
+        assertEquals("helloworld", result)
+    }
+
+    @Test
+    fun givenAnonymousFunction_return_thenComplete() {
+        var result = ""
+        "hello_world".forEach(fun(element) {
+            // local return to the caller of the anonymous fun, i.e. the forEach loop
+            if (element == '_') return
+            result += element.toString()
+        })
+        assertEquals("helloworld", result)
+    }
+
+    @Test
+    fun givenAnonymousFunction_returnToLabel_thenComplete() {
+        var result = ""
+        run loop@{
+            "hello_world".forEach {
+                // non-local return from the lambda passed to run
+                if (it == '_') return@loop
+                result += it.toString()
+            }
+        }
+        assertEquals("hello", result)
+    }
+}

ejb/ejb-remote/pom.xml

@@ -15,7 +15,6 @@
         <dependency>
             <groupId>javax</groupId>
             <artifactId>javaee-api</artifactId>
-            <version>${javaee-api.version}</version>
             <scope>provided</scope>
         </dependency>
     </dependencies>

ejb/ejb-session-beans/pom.xml

@@ -24,7 +24,6 @@
         <dependency>
             <groupId>javax</groupId>
             <artifactId>javaee-api</artifactId>
-            <version>${javaee-api.version}</version>
             <scope>provided</scope>
         </dependency>
         <dependency>

flyway-cdi-extension/pom.xml

@@ -0,0 +1,51 @@
+<?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>flyway-cdi-extension</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+
+    <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>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>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <version>1.4.197</version>
+            <scope>runtime</scope>
+        </dependency>
+    </dependencies>
+
+</project>

flyway-cdi-extension/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();
+    }
+}

flyway-cdi-extension/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 {
+}

flyway-cdi-extension/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()) {
+        }
+    }
+}

flyway-cdi-extension/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>

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

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

flyway-cdi-extension/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
+);

flyway-cdi-extension/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');

flyway/pom.xml

@@ -65,6 +65,7 @@
     <properties>
         <flyway-core.version>5.0.2</flyway-core.version>
         <flyway-maven-plugin.version>5.0.2</flyway-maven-plugin.version>
+        <h2.version>1.4.195</h2.version>
     </properties>
 
 </project>

flyway/src/test/java/com/baeldung/flywaycallbacks/FlywayApplicationUnitTest.java

@@ -16,7 +16,7 @@ import org.springframework.test.context.junit4.SpringRunner;
 @RunWith(SpringRunner.class)
 @DirtiesContext(classMode = ClassMode.AFTER_EACH_TEST_METHOD)
 @ContextConfiguration(classes = FlywayCallbackTestConfig.class)
-public class FlywayApplicationTest {
+public class FlywayApplicationUnitTest {
 
     private Log log = LogFactory.getLog(getClass());
 

gson/pom.xml

@@ -1,73 +1,73 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         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">
+         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>
+    <modelVersion>4.0.0</modelVersion>
-	<groupId>com.baeldung</groupId>
+    <groupId>com.baeldung</groupId>
-	<artifactId>gson</artifactId>
+    <artifactId>gson</artifactId>
-	<version>0.1-SNAPSHOT</version>
+    <version>0.1-SNAPSHOT</version>
-	<name>gson</name>
+    <name>gson</name>
 
-	<parent>
+    <parent>
-		<groupId>com.baeldung</groupId>
+        <groupId>com.baeldung</groupId>
-		<artifactId>parent-java</artifactId>
+        <artifactId>parent-java</artifactId>
-		<version>0.0.1-SNAPSHOT</version>
+        <version>0.0.1-SNAPSHOT</version>
-		<relativePath>../parent-java</relativePath>
+        <relativePath>../parent-java</relativePath>
-	</parent>
+    </parent>
 
-	<dependencies>
+    <dependencies>
-		<!-- utils -->
+        <!-- utils -->
-		<dependency>
+        <dependency>
-			<groupId>org.projectlombok</groupId>
+            <groupId>org.projectlombok</groupId>
-			<artifactId>lombok</artifactId>
+            <artifactId>lombok</artifactId>
-			<version>${lombok.version}</version>
+            <version>${lombok.version}</version>
-			<scope>provided</scope>
+            <scope>provided</scope>
-		</dependency>
+        </dependency>
-		<dependency>
+        <dependency>
-			<groupId>joda-time</groupId>
+            <groupId>joda-time</groupId>
-			<artifactId>joda-time</artifactId>
+            <artifactId>joda-time</artifactId>
-			<version>${joda-time.version}</version>
+            <version>${joda-time.version}</version>
-		</dependency>
+        </dependency>
-		<dependency>
+        <dependency>
-			<groupId>commons-io</groupId>
+            <groupId>commons-io</groupId>
-			<artifactId>commons-io</artifactId>
+            <artifactId>commons-io</artifactId>
-			<version>${commons-io.version}</version>
+            <version>${commons-io.version}</version>
-		</dependency>
+        </dependency>
-		<dependency>
+        <dependency>
-			<groupId>org.apache.commons</groupId>
+            <groupId>org.apache.commons</groupId>
-			<artifactId>commons-collections4</artifactId>
+            <artifactId>commons-collections4</artifactId>
-			<version>${commons-collections4.version}</version>
+            <version>${commons-collections4.version}</version>
-		</dependency>
+        </dependency>
-		<dependency>
+        <dependency>
-			<groupId>org.apache.commons</groupId>
+            <groupId>org.apache.commons</groupId>
-			<artifactId>commons-lang3</artifactId>
+            <artifactId>commons-lang3</artifactId>
-			<version>${commons-lang3.version}</version>
+            <version>${commons-lang3.version}</version>
-		</dependency>
+        </dependency>
-		<!-- marshalling -->
+        <!-- marshalling -->
-		<dependency>
+        <dependency>
-			<groupId>com.google.code.gson</groupId>
+            <groupId>com.google.code.gson</groupId>
-			<artifactId>gson</artifactId>
+            <artifactId>gson</artifactId>
-			<version>${gson.version}</version>
+            <version>${gson.version}</version>
-		</dependency>
+        </dependency>
-	</dependencies>
+    </dependencies>
 
-	<build>
+    <build>
-		<finalName>gson</finalName>
+        <finalName>gson</finalName>
-		<resources>
+        <resources>
-			<resource>
+            <resource>
-				<directory>src/main/resources</directory>
+                <directory>src/main/resources</directory>
-				<filtering>true</filtering>
+                <filtering>true</filtering>
-			</resource>
+            </resource>
-		</resources>
+        </resources>
-	</build>
+    </build>
 
-	<properties>
+    <properties>
-		<!-- marshalling -->
+        <!-- marshalling -->
-		<gson.version>2.8.0</gson.version>
+        <gson.version>2.8.0</gson.version>
-		<!-- util -->
+        <!-- util -->
-		<commons-lang3.version>3.5</commons-lang3.version>
+        <commons-lang3.version>3.5</commons-lang3.version>
-		<commons-collections4.version>4.1</commons-collections4.version>
+        <commons-collections4.version>4.1</commons-collections4.version>
-		<joda-time.version>2.9.6</joda-time.version>
+        <joda-time.version>2.9.6</joda-time.version>
         <lombok.version>1.16.10</lombok.version>
-	</properties>
+    </properties>
 
 </project>

gson/src/main/java/org/baeldung/gson/entities/Employee.java

@@ -0,0 +1,36 @@
+package org.baeldung.gson.entities;
+
+public class Employee {
+    private int id;
+    private String name;
+    private String address;
+
+    public Employee(int id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+}

gson/src/main/java/org/baeldung/gson/serialization/HashMapDeserializer.java

@@ -0,0 +1,66 @@
+package org.baeldung.gson.serialization;
+
+import java.lang.reflect.Type;
+import java.math.BigDecimal;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.baeldung.gson.entities.Employee;
+
+import com.google.gson.*;
+
+public class HashMapDeserializer implements JsonDeserializer<HashMap<String, Object>> {
+
+    @Override
+    public HashMap<String, Object> deserialize(JsonElement elem, Type type, JsonDeserializationContext context) throws JsonParseException {
+        HashMap<String, Object> map = new HashMap<>();
+        for (Map.Entry<String, JsonElement> entry : elem.getAsJsonObject().entrySet()) {
+            JsonElement jsonValue = entry.getValue();
+            Object value = null;
+            if (jsonValue.isJsonPrimitive()) {
+                value = toPrimitive(jsonValue.getAsJsonPrimitive(), context);
+            } else {
+                value = context.deserialize(jsonValue, Employee.class);
+            }
+            map.put(entry.getKey(), value);
+        }
+        return map;
+
+    }
+
+    private Object toPrimitive(JsonPrimitive jsonValue, JsonDeserializationContext context) {
+        if (jsonValue.isBoolean())
+            return jsonValue.getAsBoolean();
+        else if (jsonValue.isString())
+            return jsonValue.getAsString();
+        else {
+            BigDecimal bigDec = jsonValue.getAsBigDecimal();
+            Long l;
+            Integer i;
+            if ((i = toInteger(bigDec)) != null) {
+                return i;
+            } else if ((l = toLong(bigDec)) != null) {
+                return l;
+            } else {
+                return bigDec.doubleValue();
+            }
+        }
+    }
+
+    private Long toLong(BigDecimal val) {
+        try {
+            return val.toBigIntegerExact().longValue();
+        } catch (ArithmeticException e) {
+            return null;
+        }
+    }
+
+    private Integer toInteger(BigDecimal val) {
+        try {
+            return val.intValueExact();
+        } catch (ArithmeticException e) {
+            return null;
+        }
+    }
+
+}

gson/src/main/resources/logback.xml

@@ -7,13 +7,13 @@
         </encoder>
     </appender>
 
-    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework" level="WARN"/>
-    <logger name="org.springframework.transaction" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN"/>
 
     <!-- in order to debug some marshalling issues, this needs to be TRACE -->
-    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
+    <logger name="org.springframework.web.servlet.mvc" level="WARN"/>
 
     <root level="INFO">
-        <appender-ref ref="STDOUT" />
+        <appender-ref ref="STDOUT"/>
     </root>
 </configuration>

gson/src/test/java/org/baeldung/gson/deserialization/HashMapDeserializationUnitTest.java

@@ -0,0 +1,86 @@
+package org.baeldung.gson.deserialization;
+
+import java.lang.reflect.Type;
+import java.util.HashMap;
+
+import org.baeldung.gson.entities.Employee;
+import org.baeldung.gson.serialization.HashMapDeserializer;
+import org.junit.Assert;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonSyntaxException;
+import com.google.gson.internal.LinkedTreeMap;
+import com.google.gson.reflect.TypeToken;
+
+public class HashMapDeserializationUnitTest {
+
+    private static final Logger logger = LoggerFactory.getLogger(HashMapDeserializationUnitTest.class);
+
+    @Test
+    public void whenUsingHashMapClass_thenShouldReturnMapWithDefaultClasses() {
+
+        String jsonString = "{'employee.name':'Bob','employee.salary':10000, 'employee.active':true, "
+          + "'employee':{'id':10, 'name': 'Bob Willis', 'address':'London'}}";
+
+        Gson gson = new Gson();
+        HashMap map = gson.fromJson(jsonString, HashMap.class);
+
+        logger.info("The converted map: {}", map);
+        Assert.assertEquals(4, map.size());
+        Assert.assertEquals(Double.class, map.get("employee.salary").getClass());
+        Assert.assertEquals(LinkedTreeMap.class, map.get("employee").getClass());
+
+    }
+
+    @Test(expected = JsonSyntaxException.class)
+    public void whenUsingJsonStringWithDuplicateKey_thenShouldThrowJsonSyntaxException() {
+
+        String jsonString = "{'employee.name':'Bob', 'employee.name':'Jenny','employee.salary':10000, "
+          + "'employee.active':true, " + "'employee':{'id':10, 'name': 'Bob Willis', 'address':'London'}}";
+
+        Gson gson = new Gson();
+        HashMap map = gson.fromJson(jsonString, HashMap.class);
+
+        logger.info("The converted map: {}", map);
+    }
+
+    @Test
+    public void whenUsingTypeToken_thenShouldReturnMapWithProperClass() {
+
+        String jsonString = "{'Bob':{'id':10, 'name': 'Bob Willis', 'address':'UK'},"
+          + "'Jenny':{'id':10, 'name': 'Jenny McCarthy', 'address':'USA'}, "
+          + "'Steve':{'id':10, 'name': 'Steven Waugh', 'address':'Australia'}}";
+
+        Gson gson = new Gson();
+        Type empMapType = new TypeToken<HashMap<String, Employee>>(){}.getType();
+        HashMap<String, Employee> nameEmployeeMap = gson.fromJson(jsonString, empMapType);
+
+        logger.info("The converted map: {}", nameEmployeeMap);
+        Assert.assertEquals(3, nameEmployeeMap.size());
+        Assert.assertEquals(Employee.class, nameEmployeeMap.get("Bob").getClass());
+    }
+
+    @Test
+    public void whenUsingCustomDeserializer_thenShouldReturnMapWithProperClass() {
+
+        String jsonString = "{'employee.name':'Bob','employee.salary':10000, 'employee.active':true, "
+          + "'employee':{'id':10, 'name': 'Bob Willis', 'address':'London'}}";
+
+        Type type = new TypeToken<HashMap<String, Object>>(){}.getType();
+        Gson gson = new GsonBuilder()
+          .registerTypeAdapter(type, new HashMapDeserializer())
+          .create();
+        HashMap<String, Object> blendedMap = gson.fromJson(jsonString, type);
+
+        logger.info("The converted map: {}", blendedMap);
+        Assert.assertEquals(4, blendedMap.size());
+        Assert.assertEquals(Integer.class, blendedMap.get("employee.salary").getClass());
+        Assert.assertEquals(Employee.class, blendedMap.get("employee").getClass());
+
+    }
+
+}

gson/src/test/resources/logback-test.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <logger name="org.springframework" level="WARN"/>
+    <logger name="org.springframework.transaction" level="WARN"/>
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN"/>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT"/>
+    </root>
+</configuration>