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

2019-07-28 16:05:52 +05:30 · 2019-07-28 16:05:52 +05:30 · 3b3a0fcd67
commit 3b3a0fcd67
parent 6a29eab820 ba31134cfd
182 changed files with 3714 additions and 568 deletions
--- a/README.md
+++ b/README.md
@ -1,12 +1,16 @@

-The "REST with Spring" Classes
+The Courses
 ==============================

-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)**

-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)**
+Here's the new "Learn Spring" course: <br/>
+**[>> LEARN SPRING - THE MASTER CLASS](https://www.baeldung.com/learn-spring-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=ls#master-class)**
+
+Here's the Master Class of "REST With Spring" (along with the new announced Boot 2 material): <br/>
+**[>> THE REST WITH SPRING - MASTER CLASS](https://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](https://www.baeldung.com/learn-spring-security-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=lss#master-class)**



@ -15,7 +19,7 @@ Java and Spring Tutorials

 This project is **a collection of small and focused tutorials** - each covering a single and well defined area of development in the Java ecosystem. 
 A strong focus of these is, of course, the Spring Framework - Spring, Spring Boot and Spring Security. 
-In additional to Spring, the following technologies are in focus: `core Java`, `Jackson`, `HttpClient`, `Guava`. 
+In additional to Spring, the modules here are covering a number of aspects in Java. 


 Building the project
@ -32,8 +36,15 @@ Running a Spring Boot module
 ====================
 To run a Spring Boot module run the command: `mvn spring-boot:run` in the module directory

-###Running Tests

+Working with the IDE
+====================
+This repo contains a large number of modules. 
+When you're working with an individual module, there's no need to import all of them (or build all of them) - you can simply import that particular module in either Eclipse or IntelliJ. 
+
+
+Running Tests
+=============
 The command `mvn clean install` will run the unit tests in a module.
 To run the integration tests, use the command `mvn clean install -Pintegration-lite-first`

--- a/algorithms-miscellaneous-3/src/main/java/com/baeldung/algorithms/stringsortingbynumber/NaturalOrderComparators.java
+++ b/algorithms-miscellaneous-3/src/main/java/com/baeldung/algorithms/stringsortingbynumber/NaturalOrderComparators.java
@ -0,0 +1,30 @@
+package com.baeldung.algorithms.stringsortingbynumber;
+
+import java.util.Comparator;
+
+public final class NaturalOrderComparators {
+
+    private static final String DIGIT_AND_DECIMAL_REGEX = "[^\\d.]";
+
+    private NaturalOrderComparators() {
+        throw new AssertionError("Let's keep this static");
+    }
+
+    public static Comparator<String> createNaturalOrderRegexComparator() {
+        return Comparator.comparingDouble(NaturalOrderComparators::parseStringToNumber);
+    }
+
+    private static double parseStringToNumber(String input){
+
+        final String digitsOnly = input.replaceAll(DIGIT_AND_DECIMAL_REGEX, "");
+
+        if("".equals(digitsOnly)) return 0;
+
+        try{
+            return Double.parseDouble(digitsOnly);
+        }catch (NumberFormatException nfe){
+            return 0;
+        }
+    }
+
+}
--- a/algorithms-miscellaneous-3/src/test/java/com/baeldung/algorithms/stringsortingbynumber/NaturalOrderComparatorsUnitTest.java
+++ b/algorithms-miscellaneous-3/src/test/java/com/baeldung/algorithms/stringsortingbynumber/NaturalOrderComparatorsUnitTest.java
@ -0,0 +1,79 @@
+package com.baeldung.algorithms.stringsortingbynumber;
+
+import com.baeldung.algorithms.stringsortingbynumber.NaturalOrderComparators;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.Assert.*;
+
+public class NaturalOrderComparatorsUnitTest {
+
+    @Test
+    public void givenSimpleStringsContainingIntsAndDoubles_whenSortedByRegex_checkSortingCorrect() {
+
+        List<String> testStrings = Arrays.asList("a1", "b3", "c4", "d2.2", "d2.4", "d2.3d");
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        List<String> expected = Arrays.asList("a1", "d2.2", "d2.3d", "d2.4", "b3", "c4");
+
+        assertEquals(expected, testStrings);
+
+
+    }
+
+    @Test
+    public void givenSimpleStringsContainingIntsAndDoublesWithAnInvalidNumber_whenSortedByRegex_checkSortingCorrect() {
+
+        List<String> testStrings = Arrays.asList("a1", "b3", "c4", "d2.2", "d2.4", "d2.3.3d");
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        List<String> expected = Arrays.asList("d2.3.3d", "a1", "d2.2", "d2.4", "b3", "c4");
+
+        assertEquals(expected, testStrings);
+
+
+    }
+
+    @Test
+    public void givenAllForseenProblems_whenSortedByRegex_checkSortingCorrect() {
+
+        List<String> testStrings = Arrays.asList("a1", "b3", "c4", "d2.2", "d2.f4", "d2.3.3d");
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        List<String> expected = Arrays.asList("d2.3.3d", "a1", "d2.2", "d2.f4", "b3", "c4");
+
+        assertEquals(expected, testStrings);
+
+
+    }
+
+    @Test
+    public void givenComplexStringsContainingSeparatedNumbers_whenSortedByRegex_checkNumbersCondensedAndSorted() {
+
+        List<String> testStrings = Arrays.asList("a1b2c5", "b3ght3.2", "something65.thensomething5"); //125, 33.2, 65.5
+
+        List<String> expected = Arrays.asList("b3ght3.2", "something65.thensomething5", "a1b2c5" );
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        assertEquals(expected, testStrings);
+
+    }
+
+    @Test
+    public void givenStringsNotContainingNumbers_whenSortedByRegex_checkOrderNotChanged() {
+
+        List<String> testStrings = Arrays.asList("a", "c", "d", "e");
+        List<String> expected = new ArrayList<>(testStrings);
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        assertEquals(expected, testStrings);
+    }
+}
--- a/core-java-modules/core-java-12/README.md
+++ b/core-java-modules/core-java-12/README.md
@ -1,3 +1,4 @@
-## Relevant articles:
+## Relevant Articles:
+

 - [String API Updates in Java 12](https://www.baeldung.com/java12-string-api)
--- a/core-java-modules/core-java-arrays-2/.gitignore
+++ b/core-java-modules/core-java-arrays-2/.gitignore
@ -0,0 +1,25 @@
+*.class
+
+0.*
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+.resourceCache
+
+# Packaged files #
+*.jar
+*.war
+*.ear
+
+# Files generated by integration tests
+backup-pom.xml
+/bin/
+/temp
+
+#IntelliJ specific
+.idea/
+*.iml
--- a/core-java-modules/core-java-arrays-2/README.MD
+++ b/core-java-modules/core-java-arrays-2/README.MD
--- a/core-java-modules/core-java-arrays-2/pom.xml
+++ b/core-java-modules/core-java-arrays-2/pom.xml
@ -0,0 +1,50 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>core-java-arrays-2</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-arrays-2</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+        <!-- test scoped -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj-core.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-arrays-2</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+    <properties>
+
+        <!-- util -->
+        <commons-lang3.version>3.9</commons-lang3.version>
+        <!-- testing -->
+        <assertj-core.version>3.10.0</assertj-core.version>
+    </properties>
+
+</project>
--- a/core-java-modules/core-java-arrays-2/src/main/java/com/baeldung/array/conversions/StreamArrayConversion.java
+++ b/core-java-modules/core-java-arrays-2/src/main/java/com/baeldung/array/conversions/StreamArrayConversion.java
--- a/core-java-modules/core-java-arrays-2/src/main/java/com/baeldung/array/looping/LoopDiagonally.java
+++ b/core-java-modules/core-java-arrays-2/src/main/java/com/baeldung/array/looping/LoopDiagonally.java
--- a/core-java-modules/core-java-arrays-2/src/test/java/com/baeldung/array/conversions/StreamArrayConversionUnitTest.java
+++ b/core-java-modules/core-java-arrays-2/src/test/java/com/baeldung/array/conversions/StreamArrayConversionUnitTest.java
--- a/core-java-modules/core-java-arrays-2/src/test/java/com/baeldung/array/looping/LoopDiagonallyUnitTest.java
+++ b/core-java-modules/core-java-arrays-2/src/test/java/com/baeldung/array/looping/LoopDiagonallyUnitTest.java
@ -4,7 +4,7 @@ import org.junit.Test;

 import static org.junit.Assert.assertEquals;

-public class LoopDiagonallyTest {
+public class LoopDiagonallyUnitTest {

    @Test
    public void twoArrayIsLoopedDiagonallyAsExpected() {
--- a/core-java-modules/core-java-arrays/src/main/java/com/baeldung/array/SortedArrayChecker.java
+++ b/core-java-modules/core-java-arrays/src/main/java/com/baeldung/array/SortedArrayChecker.java
@ -2,7 +2,10 @@ package com.baeldung.array;

 import com.baeldung.arraycopy.model.Employee;

+import java.util.Comparator;
+
 public class SortedArrayChecker {
+
    boolean isSorted(int[] array, int length) {
        if (array == null || length < 2)
            return true;
@ -22,7 +25,7 @@ public class SortedArrayChecker {
        return true;
    }

-    boolean isSorted(String[] array, int length) {
+    boolean isSorted(Comparable[] array, int length) {
        if (array == null || length < 2)
            return true;

@ -32,40 +35,31 @@ public class SortedArrayChecker {
        return isSorted(array, length - 1);
    }

-boolean isSorted(String[] array) {
-    for (int i = 0; i < array.length - 1; ++i) {
-        if (array[i].compareTo(array[i + 1]) > 0)
-            return false;
-    }
-
-    return true;
-}
-
-    boolean isSortedByName(Employee[] array) {
+    boolean isSorted(Comparable[] array) {
        for (int i = 0; i < array.length - 1; ++i) {
-            if (array[i].getName().compareTo(array[i + 1].getName()) > 0)
+            if (array[i].compareTo(array[i + 1]) > 0)
                return false;
        }

        return true;
    }

-boolean isSortedByAge(Employee[] array) {
-    for (int i = 0; i < array.length - 1; ++i) {
-        if (array[i].getAge() > (array[i + 1].getAge()))
-            return false;
+    boolean isSorted(Object[] array, Comparator comparator) {
+        for (int i = 0; i < array.length - 1; ++i) {
+            if (comparator.compare(array[i], (array[i + 1])) > 0)
+                return false;
+        }
+
+        return true;
    }

-    return true;
-}
-
-    boolean isSortedByAge(Employee[] array, int length) {
+    boolean isSorted(Object[] array, Comparator comparator, int length) {
        if (array == null || length < 2)
            return true;

-        if (array[length - 2].getAge() > array[length - 1].getAge())
+        if (comparator.compare(array[length - 2], array[length - 1]) > 0)
            return false;

-        return isSortedByAge(array, length - 1);
+        return isSorted(array, comparator, length - 1);
    }
 }
--- a/core-java-modules/core-java-arrays/src/test/java/com/baeldung/array/SortedArrayCheckerUnitTest.java
+++ b/core-java-modules/core-java-arrays/src/test/java/com/baeldung/array/SortedArrayCheckerUnitTest.java
@ -4,32 +4,33 @@ import com.baeldung.arraycopy.model.Employee;
 import org.junit.Before;
 import org.junit.Test;

+import java.util.Comparator;
+
 import static org.assertj.core.api.Assertions.assertThat;

-class SortedArrayCheckerUnitTest {
-
+public class SortedArrayCheckerUnitTest {
    private static final int[] INTEGER_SORTED = {1, 3, 5, 7, 9};
    private static final int[] INTEGER_NOT_SORTED = {1, 3, 11, 7};

    private static final String[] STRING_SORTED = {"abc", "cde", "fgh"};
    private static final String[] STRING_NOT_SORTED = {"abc", "fgh", "cde", "ijk"};

-    private final Employee[] EMPLOYEES_SORTED_BY_NAME = {
+    private static final Employee[] EMPLOYEES_SORTED_BY_NAME = {
            new Employee(1, "Carlos", 26),
            new Employee(2, "Daniel", 31),
            new Employee(3, "Marta", 27)};

-    private final Employee[] EMPLOYEES_NOT_SORTED_BY_NAME = {
+    private static final Employee[] EMPLOYEES_NOT_SORTED_BY_NAME = {
            new Employee(1, "Daniel", 31),
            new Employee(2, "Carlos", 26),
            new Employee(3, "Marta", 27)};

-    private final Employee[] EMPLOYEES_SORTED_BY_AGE = {
+    private static final Employee[] EMPLOYEES_SORTED_BY_AGE = {
            new Employee(1, "Carlos", 26),
            new Employee(2, "Marta", 27),
            new Employee(3, "Daniel", 31)};

-    private final Employee[] EMPLOYEES_NOT_SORTED_BY_AGE = {
+    private static final Employee[] EMPLOYEES_NOT_SORTED_BY_AGE = {
            new Employee(1, "Marta", 27),
            new Employee(2, "Carlos", 26),
            new Employee(3, "Daniel", 31)};
@ -61,13 +62,18 @@ class SortedArrayCheckerUnitTest {

    @Test
    public void givenEmployeeArray_thenReturnIfItIsSortedOrNot() {
-        assertThat(sortedArrayChecker.isSortedByName(EMPLOYEES_SORTED_BY_NAME)).isEqualTo(true);
-        assertThat(sortedArrayChecker.isSortedByName(EMPLOYEES_NOT_SORTED_BY_NAME)).isEqualTo(false);
+        assertThat(sortedArrayChecker.isSorted(EMPLOYEES_SORTED_BY_NAME, Comparator.comparing(Employee::getName))).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(EMPLOYEES_NOT_SORTED_BY_NAME, Comparator.comparing(Employee::getName))).isEqualTo(false);

-        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_SORTED_BY_AGE)).isEqualTo(true);
-        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_NOT_SORTED_BY_AGE)).isEqualTo(false);
+        assertThat(sortedArrayChecker.isSorted(EMPLOYEES_SORTED_BY_AGE, Comparator.comparingInt(Employee::getAge))).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(EMPLOYEES_NOT_SORTED_BY_AGE, Comparator.comparingInt(Employee::getAge))).isEqualTo(false);

-        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_SORTED_BY_AGE, EMPLOYEES_SORTED_BY_AGE.length)).isEqualTo(true);
-        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_NOT_SORTED_BY_AGE, EMPLOYEES_NOT_SORTED_BY_AGE.length)).isEqualTo(false);
+        assertThat(sortedArrayChecker
+                .isSorted(EMPLOYEES_SORTED_BY_AGE, Comparator.comparingInt(Employee::getAge), EMPLOYEES_SORTED_BY_AGE.length))
+                .isEqualTo(true);
+        assertThat(sortedArrayChecker
+                .isSorted(EMPLOYEES_NOT_SORTED_BY_AGE, Comparator.comparingInt(Employee::getAge), EMPLOYEES_NOT_SORTED_BY_AGE.length))
+                .isEqualTo(false);
    }
+
 }
--- a/core-java-modules/core-java-exceptions/README.md
+++ b/core-java-modules/core-java-exceptions/README.md
@ -1,3 +1,3 @@
-## Relevant articles:
+## Relevant Articles:

 - [Will an Error Be Caught by Catch Block in Java?](https://www.baeldung.com/java-error-catch)
--- a/core-java-modules/core-java-networking-2/.gitignore
+++ b/core-java-modules/core-java-networking-2/.gitignore
@ -0,0 +1,25 @@
+*.class
+
+0.*
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+.resourceCache
+
+# Packaged files #
+*.jar
+*.war
+*.ear
+
+# Files generated by integration tests
+backup-pom.xml
+/bin/
+/temp
+
+#IntelliJ specific
+.idea/
+*.iml
--- a/core-java-modules/core-java-networking-2/pom.xml
+++ b/core-java-modules/core-java-networking-2/pom.xml
@ -0,0 +1,20 @@
+<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>core-java-networking-2</artifactId>
+    <name>core-java-networking-2</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-networking-2</finalName>
+    </build>	
+</project>
--- a/core-java-modules/core-java-networking-2/src/main/java/com/baeldung/url/UrlChecker.java
+++ b/core-java-modules/core-java-networking-2/src/main/java/com/baeldung/url/UrlChecker.java
@ -0,0 +1,25 @@
+package com.baeldung.url;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+public class UrlChecker {
+
+    public int getResponseCodeForURL(String address) throws IOException {
+        return getResponseCodeForURLUsing(address, "GET");
+    }
+
+    public int getResponseCodeForURLUsingHead(String address) throws IOException {
+        return getResponseCodeForURLUsing(address, "HEAD");
+    }
+
+    private int getResponseCodeForURLUsing(String address, String method) throws IOException {
+        HttpURLConnection.setFollowRedirects(false); // Set follow redirects to false
+        final URL url = new URL(address);
+        HttpURLConnection huc = (HttpURLConnection) url.openConnection();
+        huc.setRequestMethod(method);
+        return huc.getResponseCode();
+    }
+
+}
--- a/core-java-modules/core-java-networking-2/src/test/java/com/baeldung/url/UrlCheckerUnitTest.java
+++ b/core-java-modules/core-java-networking-2/src/test/java/com/baeldung/url/UrlCheckerUnitTest.java
@ -0,0 +1,39 @@
+package com.baeldung.url;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+public class UrlCheckerUnitTest {
+
+    @Test
+    public void givenValidUrl_WhenUsingHEAD_ThenReturn200() throws IOException {
+        UrlChecker tester = new UrlChecker();
+        int responseCode = tester.getResponseCodeForURLUsingHead("http://www.example.com");
+        assertEquals(200, responseCode);
+    }
+    
+    @Test
+    public void givenInvalidIUrl_WhenUsingHEAD_ThenReturn404() throws IOException {
+        UrlChecker tester = new UrlChecker();
+        int responseCode = tester.getResponseCodeForURLUsingHead("http://www.example.com/unkownurl");
+        assertEquals(404, responseCode);
+    }
+    
+    @Test
+    public void givenValidUrl_WhenUsingGET_ThenReturn200() throws IOException {
+        UrlChecker tester = new UrlChecker();
+        int responseCode = tester.getResponseCodeForURL("http://www.example.com");
+        assertEquals(200, responseCode);
+    }
+    
+    @Test
+    public void givenInvalidIUrl_WhenUsingGET_ThenReturn404() throws IOException {
+        UrlChecker tester = new UrlChecker();
+        int responseCode = tester.getResponseCodeForURL("http://www.example.com/unkownurl");
+        assertEquals(404, responseCode);
+    }
+    
+}
--- a/core-java-modules/multimodulemavenproject/README.md
+++ b/core-java-modules/multimodulemavenproject/README.md
@ -0,0 +1,3 @@
+## Relevant Articles
+
+- [Multi-Module Maven Application with Java Modules](https://www.baeldung.com/maven-multi-module-project-java-jpms)
--- a/core-java-modules/pom.xml
+++ b/core-java-modules/pom.xml
@ -17,6 +17,7 @@
        <module>pre-jpms</module>
        <module>core-java-exceptions</module>
        <module>core-java-optional</module>
+        <module>core-java-networking-2</module>
    </modules>
    
 </project>
--- a/data-structures/src/main/java/com/baeldung/graph/Graph.java
+++ b/data-structures/src/main/java/com/baeldung/graph/Graph.java
@ -0,0 +1,72 @@
+package com.baeldung.graph;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Stack;
+
+public class Graph {
+
+    private Map<Integer, List<Integer>> adjVertices;
+
+    public Graph() {
+        this.adjVertices = new HashMap<Integer, List<Integer>>();
+    }
+
+    public void addVertex(int vertex) {
+        adjVertices.putIfAbsent(vertex, new ArrayList<>());
+    }
+
+    public void addEdge(int src, int dest) {
+        adjVertices.get(src).add(dest);
+    }
+
+    public void dfsWithoutRecursion(int start) {
+        Stack<Integer> stack = new Stack<Integer>();
+        boolean[] isVisited = new boolean[adjVertices.size()];
+        stack.push(start);
+        while (!stack.isEmpty()) {
+            int current = stack.pop();
+            isVisited[current] = true;
+            System.out.print(" " + current);
+            for (int dest : adjVertices.get(current)) {
+                if (!isVisited[dest])
+                    stack.push(dest);
+            }
+        }
+    }
+
+    public void dfs(int start) {
+        boolean[] isVisited = new boolean[adjVertices.size()];
+        dfsRecursive(start, isVisited);
+    }
+
+    private void dfsRecursive(int current, boolean[] isVisited) {
+        isVisited[current] = true;
+        System.out.print(" " + current);
+        for (int dest : adjVertices.get(current)) {
+            if (!isVisited[dest])
+                dfsRecursive(dest, isVisited);
+        }
+    }
+
+    public void topologicalSort(int start) {
+        Stack<Integer> result = new Stack<Integer>();
+        boolean[] isVisited = new boolean[adjVertices.size()];
+        topologicalSortRecursive(start, isVisited, result);
+        while (!result.isEmpty()) {
+            System.out.print(" " + result.pop());
+        }
+    }
+
+    private void topologicalSortRecursive(int current, boolean[] isVisited, Stack<Integer> result) {
+        isVisited[current] = true;
+        for (int dest : adjVertices.get(current)) {
+            if (!isVisited[dest])
+                topologicalSortRecursive(dest, isVisited, result);
+        }
+        result.push(current);
+    }
+
+}
--- a/data-structures/src/main/java/com/baeldung/tree/BinaryTree.java
+++ b/data-structures/src/main/java/com/baeldung/tree/BinaryTree.java
@ -2,6 +2,7 @@ package com.baeldung.tree;

 import java.util.LinkedList;
 import java.util.Queue;
+import java.util.Stack;

 public class BinaryTree {

@ -147,6 +148,68 @@ public class BinaryTree {
        }
    }

+    
+    public void traverseInOrderWithoutRecursion() {
+        Stack<Node> stack = new Stack<Node>();
+        Node current = root;
+        stack.push(root);
+        while(! stack.isEmpty()) {
+            while(current.left != null) {
+                current = current.left;                
+                stack.push(current);                
+            }
+            current = stack.pop();
+            System.out.print(" " + current.value);
+            if(current.right != null) {
+                current = current.right;                
+                stack.push(current);
+            }
+        }
+    }
+    
+    public void traversePreOrderWithoutRecursion() {
+        Stack<Node> stack = new Stack<Node>();
+        Node current = root;
+        stack.push(root);
+        while(! stack.isEmpty()) {
+            current = stack.pop();
+            System.out.print(" " + current.value);
+            
+            if(current.right != null)
+                stack.push(current.right);
+                
+            if(current.left != null)
+                stack.push(current.left);
+        }        
+    }
+    
+    public void traversePostOrderWithoutRecursion() {
+        Stack<Node> stack = new Stack<Node>();
+        Node prev = root;
+        Node current = root;
+        stack.push(root);
+
+        while (!stack.isEmpty()) {
+            current = stack.peek();
+            boolean hasChild = (current.left != null || current.right != null);
+            boolean isPrevLastChild = (prev == current.right || (prev == current.left && current.right == null));
+
+            if (!hasChild || isPrevLastChild) {
+                current = stack.pop();
+                System.out.print(" " + current.value);
+                prev = current;
+            } else {
+                if (current.right != null) {
+                    stack.push(current.right);
+                }
+                if (current.left != null) {
+                    stack.push(current.left);
+                }
+            }
+        }   
+    }    
+    
+    
    class Node {
        int value;
        Node left;
--- a/data-structures/src/test/java/com/baeldung/graph/GraphUnitTest.java
+++ b/data-structures/src/test/java/com/baeldung/graph/GraphUnitTest.java
@ -0,0 +1,37 @@
+package com.baeldung.graph;
+
+import org.junit.Test;
+
+public class GraphUnitTest {
+
+    @Test
+    public void givenDirectedGraph_whenDFS_thenPrintAllValues() {
+        Graph graph = createDirectedGraph();
+        graph.dfs(0);
+        System.out.println();
+        graph.dfsWithoutRecursion(0);
+    }
+
+    @Test
+    public void givenDirectedGraph_whenGetTopologicalSort_thenPrintValuesSorted() {
+        Graph graph = createDirectedGraph();
+        graph.topologicalSort(0);
+    }
+
+    private Graph createDirectedGraph() {
+        Graph graph = new Graph();
+        graph.addVertex(0);
+        graph.addVertex(1);
+        graph.addVertex(2);
+        graph.addVertex(3);
+        graph.addVertex(4);
+        graph.addVertex(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(1, 3);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 4);
+        graph.addEdge(4, 5);
+        return graph;
+    }
+}
--- a/data-structures/src/test/java/com/baeldung/tree/BinaryTreeUnitTest.java
+++ b/data-structures/src/test/java/com/baeldung/tree/BinaryTreeUnitTest.java
@ -87,6 +87,8 @@ public class BinaryTreeUnitTest {
        BinaryTree bt = createBinaryTree();

        bt.traverseInOrder(bt.root);
+        System.out.println();
+        bt.traverseInOrderWithoutRecursion();
    }

    @Test
@ -95,6 +97,8 @@ public class BinaryTreeUnitTest {
        BinaryTree bt = createBinaryTree();

        bt.traversePreOrder(bt.root);
+        System.out.println();
+        bt.traversePreOrderWithoutRecursion();
    }

    @Test
@ -103,6 +107,8 @@ public class BinaryTreeUnitTest {
        BinaryTree bt = createBinaryTree();

        bt.traversePostOrder(bt.root);
+        System.out.println();
+        bt.traversePostOrderWithoutRecursion();
    }

    @Test
--- a/java-strings-2/src/test/java/com/baeldung/string/changecase/ToLowerCaseUnitTest.java
+++ b/java-strings-2/src/test/java/com/baeldung/string/changecase/ToLowerCaseUnitTest.java
@ -0,0 +1,29 @@
+package com.baeldung.string.changecase;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Locale;
+
+import org.junit.Test;
+
+public class ToLowerCaseUnitTest {
+
+    private static final Locale TURKISH = new Locale("tr");
+    private String name = "John Doe";
+    private String foreignUppercase = "\u0049";
+
+    @Test
+    public void givenMixedCaseString_WhenToLowerCase_ThenResultIsLowerCase() {
+        assertEquals("john doe", name.toLowerCase());
+    }
+
+    @Test
+    public void givenForeignString_WhenToLowerCaseWithoutLocale_ThenResultIsLowerCase() {
+        assertEquals("\u0069", foreignUppercase.toLowerCase());
+    }
+
+    @Test
+    public void givenForeignString_WhenToLowerCaseWithLocale_ThenResultIsLowerCase() {
+        assertEquals("\u0131", foreignUppercase.toLowerCase(TURKISH));
+    }
+}
--- a/java-strings-2/src/test/java/com/baeldung/string/changecase/ToUpperCaseUnitTest.java
+++ b/java-strings-2/src/test/java/com/baeldung/string/changecase/ToUpperCaseUnitTest.java
@ -0,0 +1,29 @@
+package com.baeldung.string.changecase;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Locale;
+
+import org.junit.Test;
+
+public class ToUpperCaseUnitTest {
+
+    private static final Locale TURKISH = new Locale("tr");
+    private String name = "John Doe";
+    private String foreignLowercase = "\u0069";
+
+    @Test
+    public void givenMixedCaseString_WhenToUpperCase_ThenResultIsUpperCase() {
+        assertEquals("JOHN DOE", name.toUpperCase());
+    }
+
+    @Test
+    public void givenForeignString_WhenToUpperCaseWithoutLocale_ThenResultIsUpperCase() {
+        assertEquals("\u0049", foreignLowercase.toUpperCase());
+    }
+
+    @Test
+    public void givenForeignString_WhenToUpperCaseWithLocale_ThenResultIsUpperCase() {
+        assertEquals("\u0130", foreignLowercase.toUpperCase(TURKISH));
+    }
+}
--- a/javaxval/src/main/java/org/baeldung/javabeanconstraints/bigdecimal/Invoice.java
+++ b/javaxval/src/main/java/org/baeldung/javabeanconstraints/bigdecimal/Invoice.java
@ -0,0 +1,19 @@
+package org.baeldung.javabeanconstraints.bigdecimal;
+
+import java.math.BigDecimal;
+
+import javax.validation.constraints.DecimalMin;
+import javax.validation.constraints.Digits;
+
+public class Invoice {
+	
+	@DecimalMin(value = "0.0", inclusive = false)
+	@Digits(integer=3, fraction=2)
+    private BigDecimal price;
+    private String description;
+    
+	public Invoice(BigDecimal price, String description) {
+		this.price = price;
+		this.description = description;
+	}
+}
--- a/javaxval/src/test/java/org/baeldung/javabeanconstraints/bigdecimal/InvoiceUnitTest.java
+++ b/javaxval/src/test/java/org/baeldung/javabeanconstraints/bigdecimal/InvoiceUnitTest.java
@ -0,0 +1,62 @@
+package org.baeldung.javabeanconstraints.bigdecimal;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.math.BigDecimal;
+import java.util.Set;
+
+import javax.validation.ConstraintViolation;
+import javax.validation.Validation;
+import javax.validation.Validator;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class InvoiceUnitTest {
+	
+	private static Validator validator;
+
+    @BeforeClass
+    public static void setupValidatorInstance() {
+        validator = Validation.buildDefaultValidatorFactory().getValidator();
+    }
+    
+    @Test
+    public void whenPriceIntegerDigitLessThanThreeWithDecimalValue_thenShouldGiveConstraintViolations() {
+    	Invoice invoice = new Invoice(new BigDecimal(10.21), "Book purchased");
+        Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
+        assertThat(violations.size()).isEqualTo(1);
+        violations.forEach(action-> assertThat(action.getMessage()).isEqualTo("numeric value out of bounds (<3 digits>.<2 digits> expected)"));
+    }
+    
+    @Test
+    public void whenPriceIntegerDigitLessThanThreeWithIntegerValue_thenShouldNotGiveConstraintViolations() {
+    	Invoice invoice = new Invoice(new BigDecimal(10), "Book purchased");
+        Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
+        assertThat(violations.size()).isEqualTo(0);
+    }
+    
+    @Test
+    public void whenPriceIntegerDigitGreaterThanThree_thenShouldGiveConstraintViolations() {
+    	Invoice invoice = new Invoice(new BigDecimal(1021.21), "Book purchased");
+        Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
+        assertThat(violations.size()).isEqualTo(1);
+        violations.forEach(action-> assertThat(action.getMessage()).isEqualTo("numeric value out of bounds (<3 digits>.<2 digits> expected)"));
+    }
+    
+    @Test
+    public void whenPriceIsZero_thenShouldGiveConstraintViolations() {
+    	Invoice invoice = new Invoice(new BigDecimal(000.00), "Book purchased");
+        Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
+        assertThat(violations.size()).isEqualTo(1);
+        violations.forEach(action-> assertThat(action.getMessage()).isEqualTo("must be greater than 0.0"));
+    }
+    
+    @Test
+    public void whenPriceIsGreaterThanZero_thenShouldNotGiveConstraintViolations() {
+    	Invoice invoice = new Invoice(new BigDecimal(100.50), "Book purchased");
+        Set<ConstraintViolation<Invoice>> violations = validator.validate(invoice);
+        assertThat(violations.size()).isEqualTo(0);
+    }
+
+}
--- a/jgit/README.md
+++ b/jgit/README.md
--- a/jgit/pom.xml
+++ b/jgit/pom.xml
--- a/jgit/src/main/java/com/baeldung/jgit/CreateNewRepository.java
+++ b/jgit/src/main/java/com/baeldung/jgit/CreateNewRepository.java
--- a/jgit/src/main/java/com/baeldung/jgit/OpenRepository.java
+++ b/jgit/src/main/java/com/baeldung/jgit/OpenRepository.java
--- a/jgit/src/main/java/com/baeldung/jgit/helper/Helper.java
+++ b/jgit/src/main/java/com/baeldung/jgit/helper/Helper.java
--- a/jgit/src/main/java/com/baeldung/jgit/porcelain/AddFile.java
+++ b/jgit/src/main/java/com/baeldung/jgit/porcelain/AddFile.java
--- a/jgit/src/main/java/com/baeldung/jgit/porcelain/CommitAll.java
+++ b/jgit/src/main/java/com/baeldung/jgit/porcelain/CommitAll.java
--- a/jgit/src/main/java/com/baeldung/jgit/porcelain/CreateAndDeleteTag.java
+++ b/jgit/src/main/java/com/baeldung/jgit/porcelain/CreateAndDeleteTag.java
--- a/jgit/src/main/java/com/baeldung/jgit/porcelain/Log.java
+++ b/jgit/src/main/java/com/baeldung/jgit/porcelain/Log.java
--- a/jgit/src/main/resources/logback.xml
+++ b/jgit/src/main/resources/logback.xml
--- a/jgit/src/test/java/com/baeldung/jgit/JGitBugIntegrationTest.java
+++ b/jgit/src/test/java/com/baeldung/jgit/JGitBugIntegrationTest.java
--- a/jgit/src/test/java/com/baeldung/jgit/porcelain/PorcelainUnitTest.java
+++ b/jgit/src/test/java/com/baeldung/jgit/porcelain/PorcelainUnitTest.java
--- a/jhipster/jhipster-microservice/README.md
+++ b/jhipster/jhipster-microservice/README.md
@ -0,0 +1,3 @@
+## Relevant Articles
+
+- [JHipster with a Microservice Architecture](https://www.baeldung.com/jhipster-microservices)
--- a/jhipster/jhipster-monolithic/README.md
+++ b/jhipster/jhipster-monolithic/README.md
@ -1,4 +1,6 @@
-### Relevant articles
+## Relevant Articles
+
+- [Intro to JHipster](https://www.baeldung.com/jhipster)


 # baeldung
--- a/jhipster/jhipster-uaa/README.md
+++ b/jhipster/jhipster-uaa/README.md
@ -0,0 +1,3 @@
+## Relevant Articles
+
+- [Building a Basic UAA-Secured JHipster Microservice](https://www.baeldung.com/jhipster-uaa-secured-micro-service)
--- a/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/api/AuthorizationEndpoint.java
+++ b/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/api/AuthorizationEndpoint.java
@ -121,8 +121,8 @@ public class AuthorizationEndpoint {
        String redirectUri = originalParams.getFirst("resolved_redirect_uri");
        StringBuilder sb = new StringBuilder(redirectUri);

-        String approbationStatus = params.getFirst("approbation_status");
-        if ("NO".equals(approbationStatus)) {
+        String approvalStatus = params.getFirst("approval_status");
+        if ("NO".equals(approvalStatus)) {
            URI location = UriBuilder.fromUri(sb.toString())
                    .queryParam("error", "User doesn't approved the request.")
                    .queryParam("error_description", "User doesn't approved the request.")
--- a/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/api/TokenEndpoint.java
+++ b/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/api/TokenEndpoint.java
@ -15,15 +15,14 @@ import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.MultivaluedMap;
 import javax.ws.rs.core.Response;
+import java.util.Arrays;
 import java.util.Base64;
-import java.util.Collections;
 import java.util.List;
-import java.util.Objects;

@Path("token")
 public class TokenEndpoint {

-    List<String> supportedGrantTypes = Collections.singletonList("authorization_code");
+    List<String> supportedGrantTypes = Arrays.asList("authorization_code", "refresh_token");

    @Inject
    private AppDataRepository appDataRepository;
@ -39,36 +38,36 @@ public class TokenEndpoint {

        //Check grant_type params
        String grantType = params.getFirst("grant_type");
-        Objects.requireNonNull(grantType, "grant_type params is required");
-        if (!supportedGrantTypes.contains(grantType)) {
-            JsonObject error = Json.createObjectBuilder()
-                    .add("error", "unsupported_grant_type")
-                    .add("error_description", "grant type should be one of :" + supportedGrantTypes)
-                    .build();
-            return Response.status(Response.Status.BAD_REQUEST)
-                    .entity(error).build();
+        if (grantType == null || grantType.isEmpty())
+            return responseError("Invalid_request", "grant_type is required", Response.Status.BAD_REQUEST);

+        if (!supportedGrantTypes.contains(grantType)) {
+            return responseError("unsupported_grant_type", "grant_type should be one of :" + supportedGrantTypes, Response.Status.BAD_REQUEST);
        }

        //Client Authentication
        String[] clientCredentials = extract(authHeader);
+        if (clientCredentials.length != 2) {
+            return responseError("Invalid_request", "Bad Credentials client_id/client_secret", Response.Status.BAD_REQUEST);
+        }
        String clientId = clientCredentials[0];
-        String clientSecret = clientCredentials[1];
        Client client = appDataRepository.getClient(clientId);
-        if (client == null || clientSecret == null || !clientSecret.equals(client.getClientSecret())) {
-            JsonObject error = Json.createObjectBuilder()
-                    .add("error", "invalid_client")
-                    .build();
-            return Response.status(Response.Status.UNAUTHORIZED)
-                    .entity(error).build();
+        if (client == null) {
+            return responseError("Invalid_request", "Invalid client_id", Response.Status.BAD_REQUEST);
+        }
+        String clientSecret = clientCredentials[1];
+        if (!clientSecret.equals(client.getClientSecret())) {
+            return responseError("Invalid_request", "Invalid client_secret", Response.Status.UNAUTHORIZED);
        }

        AuthorizationGrantTypeHandler authorizationGrantTypeHandler = authorizationGrantTypeHandlers.select(NamedLiteral.of(grantType)).get();
        JsonObject tokenResponse = null;
        try {
            tokenResponse = authorizationGrantTypeHandler.createAccessToken(clientId, params);
+        } catch (WebApplicationException e) {
+            return e.getResponse();
        } catch (Exception e) {
-            e.printStackTrace();
+            return responseError("Invalid_request", "Can't get token", Response.Status.INTERNAL_SERVER_ERROR);
        }

        return Response.ok(tokenResponse)
@ -81,6 +80,15 @@ public class TokenEndpoint {
        if (authHeader != null && authHeader.startsWith("Basic ")) {
            return new String(Base64.getDecoder().decode(authHeader.substring(6))).split(":");
        }
-        return null;
+        return new String[]{};
+    }
+
+    private Response responseError(String error, String errorDescription, Response.Status status) {
+        JsonObject errorResponse = Json.createObjectBuilder()
+                .add("error", error)
+                .add("error_description", errorDescription)
+                .build();
+        return Response.status(status)
+                .entity(errorResponse).build();
    }
 }
--- a/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/handler/AbstractGrantTypeHandler.java
+++ b/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/handler/AbstractGrantTypeHandler.java
@ -0,0 +1,87 @@
+package com.baeldung.oauth2.authorization.server.handler;
+
+import com.baeldung.oauth2.authorization.server.PEMKeyUtils;
+import com.nimbusds.jose.*;
+import com.nimbusds.jose.crypto.RSASSASigner;
+import com.nimbusds.jose.crypto.RSASSAVerifier;
+import com.nimbusds.jose.jwk.JWK;
+import com.nimbusds.jose.jwk.RSAKey;
+import com.nimbusds.jwt.JWTClaimsSet;
+import com.nimbusds.jwt.SignedJWT;
+import org.eclipse.microprofile.config.Config;
+
+import javax.inject.Inject;
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+import java.util.Arrays;
+import java.util.Date;
+import java.util.UUID;
+
+public abstract class AbstractGrantTypeHandler implements AuthorizationGrantTypeHandler {
+
+    //Always RSA 256, but could be parametrized
+    protected JWSHeader jwsHeader = new JWSHeader.Builder(JWSAlgorithm.RS256).type(JOSEObjectType.JWT).build();
+
+    @Inject
+    protected Config config;
+
+    //30 min
+    protected Long expiresInMin = 30L;
+
+    protected JWSVerifier getJWSVerifier() throws Exception {
+        String verificationkey = config.getValue("verificationkey", String.class);
+        String pemEncodedRSAPublicKey = PEMKeyUtils.readKeyAsString(verificationkey);
+        RSAKey rsaPublicKey = (RSAKey) JWK.parseFromPEMEncodedObjects(pemEncodedRSAPublicKey);
+        return new RSASSAVerifier(rsaPublicKey);
+    }
+
+    protected JWSSigner getJwsSigner() throws Exception {
+        String signingkey = config.getValue("signingkey", String.class);
+        String pemEncodedRSAPrivateKey = PEMKeyUtils.readKeyAsString(signingkey);
+        RSAKey rsaKey = (RSAKey) JWK.parseFromPEMEncodedObjects(pemEncodedRSAPrivateKey);
+        return new RSASSASigner(rsaKey.toRSAPrivateKey());
+    }
+
+    protected String getAccessToken(String clientId, String subject, String approvedScope) throws Exception {
+        //4. Signing
+        JWSSigner jwsSigner = getJwsSigner();
+
+        Instant now = Instant.now();
+        //Long expiresInMin = 30L;
+        Date expirationTime = Date.from(now.plus(expiresInMin, ChronoUnit.MINUTES));
+
+        //3. JWT Payload or claims
+        JWTClaimsSet jwtClaims = new JWTClaimsSet.Builder()
+                .issuer("http://localhost:9080")
+                .subject(subject)
+                .claim("upn", subject)
+                .claim("client_id", clientId)
+                .audience("http://localhost:9280")
+                .claim("scope", approvedScope)
+                .claim("groups", Arrays.asList(approvedScope.split(" ")))
+                .expirationTime(expirationTime) // expires in 30 minutes
+                .notBeforeTime(Date.from(now))
+                .issueTime(Date.from(now))
+                .jwtID(UUID.randomUUID().toString())
+                .build();
+        SignedJWT signedJWT = new SignedJWT(jwsHeader, jwtClaims);
+        signedJWT.sign(jwsSigner);
+        return signedJWT.serialize();
+    }
+
+    protected String getRefreshToken(String clientId, String subject, String approvedScope) throws Exception {
+        JWSSigner jwsSigner = getJwsSigner();
+        Instant now = Instant.now();
+        //6.Build refresh token
+        JWTClaimsSet refreshTokenClaims = new JWTClaimsSet.Builder()
+                .subject(subject)
+                .claim("client_id", clientId)
+                .claim("scope", approvedScope)
+                //refresh token for 1 day.
+                .expirationTime(Date.from(now.plus(1, ChronoUnit.DAYS)))
+                .build();
+        SignedJWT signedRefreshToken = new SignedJWT(jwsHeader, refreshTokenClaims);
+        signedRefreshToken.sign(jwsSigner);
+        return signedRefreshToken.serialize();
+    }
+}
--- a/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/handler/AuthorizationCodeGrantTypeHandler.java
+++ b/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/handler/AuthorizationCodeGrantTypeHandler.java
@ -1,18 +1,7 @@
 package com.baeldung.oauth2.authorization.server.handler;

-import com.baeldung.oauth2.authorization.server.PEMKeyUtils;
 import com.baeldung.oauth2.authorization.server.model.AuthorizationCode;
-import com.nimbusds.jose.JOSEObjectType;
-import com.nimbusds.jose.JWSAlgorithm;
-import com.nimbusds.jose.JWSHeader;
-import com.nimbusds.jose.crypto.RSASSASigner;
-import com.nimbusds.jose.jwk.JWK;
-import com.nimbusds.jose.jwk.RSAKey;
-import com.nimbusds.jwt.JWTClaimsSet;
-import com.nimbusds.jwt.SignedJWT;
-import org.eclipse.microprofile.config.Config;

-import javax.inject.Inject;
 import javax.inject.Named;
 import javax.json.Json;
 import javax.json.JsonObject;
@ -20,22 +9,14 @@ import javax.persistence.EntityManager;
 import javax.persistence.PersistenceContext;
 import javax.ws.rs.WebApplicationException;
 import javax.ws.rs.core.MultivaluedMap;
-import java.time.Instant;
 import java.time.LocalDateTime;
-import java.time.temporal.ChronoUnit;
-import java.util.Arrays;
-import java.util.Date;
-import java.util.UUID;

@Named("authorization_code")
-public class AuthorizationCodeGrantTypeHandler implements AuthorizationGrantTypeHandler {
+public class AuthorizationCodeGrantTypeHandler extends AbstractGrantTypeHandler {

    @PersistenceContext
    private EntityManager entityManager;

-    @Inject
-    private Config config;
-
    @Override
    public JsonObject createAccessToken(String clientId, MultivaluedMap<String, String> params) throws Exception {
        //1. code is required
@ -58,42 +39,16 @@ public class AuthorizationCodeGrantTypeHandler implements AuthorizationGrantType
            throw new WebApplicationException("invalid_grant");
        }

-        //JWT Header
-        JWSHeader jwsHeader = new JWSHeader.Builder(JWSAlgorithm.RS256).type(JOSEObjectType.JWT).build();
-
-        Instant now = Instant.now();
-        Long expiresInMin = 30L;
-        Date expiresIn = Date.from(now.plus(expiresInMin, ChronoUnit.MINUTES));
-
        //3. JWT Payload or claims
-        JWTClaimsSet jwtClaims = new JWTClaimsSet.Builder()
-                .issuer("http://localhost:9080")
-                .subject(authorizationCode.getUserId())
-                .claim("upn", authorizationCode.getUserId())
-                .audience("http://localhost:9280")
-                .claim("scope", authorizationCode.getApprovedScopes())
-                .claim("groups", Arrays.asList(authorizationCode.getApprovedScopes().split(" ")))
-                .expirationTime(expiresIn) // expires in 30 minutes
-                .notBeforeTime(Date.from(now))
-                .issueTime(Date.from(now))
-                .jwtID(UUID.randomUUID().toString())
-                .build();
-        SignedJWT signedJWT = new SignedJWT(jwsHeader, jwtClaims);
-
-        //4. Signing
-        String signingkey = config.getValue("signingkey", String.class);
-        String pemEncodedRSAPrivateKey = PEMKeyUtils.readKeyAsString(signingkey);
-        RSAKey rsaKey = (RSAKey) JWK.parseFromPEMEncodedObjects(pemEncodedRSAPrivateKey);
-        signedJWT.sign(new RSASSASigner(rsaKey.toRSAPrivateKey()));
-
-        //5. Finally the JWT access token
-        String accessToken = signedJWT.serialize();
+        String accessToken = getAccessToken(clientId, authorizationCode.getUserId(), authorizationCode.getApprovedScopes());
+        String refreshToken = getRefreshToken(clientId, authorizationCode.getUserId(), authorizationCode.getApprovedScopes());

        return Json.createObjectBuilder()
                .add("token_type", "Bearer")
                .add("access_token", accessToken)
                .add("expires_in", expiresInMin * 60)
                .add("scope", authorizationCode.getApprovedScopes())
+                .add("refresh_token", refreshToken)
                .build();
    }
 }
--- a/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/handler/RefreshTokenGrantTypeHandler.java
+++ b/oauth2-framework-impl/oauth2-authorization-server/src/main/java/com/baeldung/oauth2/authorization/server/handler/RefreshTokenGrantTypeHandler.java
@ -0,0 +1,72 @@
+package com.baeldung.oauth2.authorization.server.handler;
+
+import com.nimbusds.jose.JWSVerifier;
+import com.nimbusds.jwt.SignedJWT;
+
+import javax.inject.Named;
+import javax.json.Json;
+import javax.json.JsonObject;
+import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.MultivaluedMap;
+import javax.ws.rs.core.Response;
+import java.util.Arrays;
+import java.util.Date;
+import java.util.HashSet;
+import java.util.Set;
+
+@Named("refresh_token")
+public class RefreshTokenGrantTypeHandler extends AbstractGrantTypeHandler {
+
+    @Override
+    public JsonObject createAccessToken(String clientId, MultivaluedMap<String, String> params) throws Exception {
+        String refreshToken = params.getFirst("refresh_token");
+        if (refreshToken == null || "".equals(refreshToken)) {
+            throw new WebApplicationException("invalid_grant");
+        }
+
+        //Decode refresh token
+        SignedJWT signedRefreshToken = SignedJWT.parse(refreshToken);
+        JWSVerifier verifier = getJWSVerifier();
+
+        if (!signedRefreshToken.verify(verifier)) {
+            throw new WebApplicationException("Invalid refresh token.");
+        }
+        if (!(new Date().before(signedRefreshToken.getJWTClaimsSet().getExpirationTime()))) {
+            throw new WebApplicationException("Refresh token expired.");
+        }
+        String refreshTokenClientId = signedRefreshToken.getJWTClaimsSet().getStringClaim("client_id");
+        if (!clientId.equals(refreshTokenClientId)) {
+            throw new WebApplicationException("Invalid client_id.");
+        }
+
+        //At this point, the refresh token is valid and not yet expired
+        //So create a new access token from it.
+        String subject = signedRefreshToken.getJWTClaimsSet().getSubject();
+        String approvedScopes = signedRefreshToken.getJWTClaimsSet().getStringClaim("scope");
+
+        String requestedScopes = params.getFirst("scope");
+        if (requestedScopes != null && !requestedScopes.isEmpty()) {
+            Set<String> rScopes = new HashSet(Arrays.asList(requestedScopes.split(" ")));
+            Set<String> aScopes = new HashSet(Arrays.asList(approvedScopes.split(" ")));
+            if (!aScopes.containsAll(rScopes)) {
+                JsonObject error = Json.createObjectBuilder()
+                        .add("error", "Invalid_request")
+                        .add("error_description", "Requested scopes should be a subset of the original scopes.")
+                        .build();
+                Response response = Response.status(Response.Status.BAD_REQUEST).entity(error).build();
+                throw new WebApplicationException(response);
+            }
+        } else {
+            requestedScopes = approvedScopes;
+        }
+
+        String accessToken = getAccessToken(clientId, subject, requestedScopes);
+        return Json.createObjectBuilder()
+                .add("token_type", "Bearer")
+                .add("access_token", accessToken)
+                .add("expires_in", expiresInMin * 60)
+                .add("scope", requestedScopes)
+                .add("refresh_token", refreshToken)
+                .build();
+    }
+}
--- a/oauth2-framework-impl/oauth2-authorization-server/src/main/webapp/authorize.jsp
+++ b/oauth2-framework-impl/oauth2-authorization-server/src/main/webapp/authorize.jsp
@ -41,8 +41,8 @@

            <tr>
                <td colspan="2">
-                    <input type="submit" name="approbation_status" value="YES"/>
-                    <input type="submit" name="approbation_status" value="NO"/>
+                    <input type="submit" name="approval_status" value="YES"/>
+                    <input type="submit" name="approval_status" value="NO"/>
                </td>
            </tr>
        </table>
--- a/oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/AbstractServlet.java
+++ b/oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/AbstractServlet.java
@ -0,0 +1,23 @@
+package com.baeldung.oauth2.client;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.Base64;
+
+public abstract class AbstractServlet extends HttpServlet {
+
+    protected void dispatch(String location, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        RequestDispatcher requestDispatcher = request.getRequestDispatcher(location);
+        requestDispatcher.forward(request, response);
+    }
+
+    protected String getAuthorizationHeaderValue(String clientId, String clientSecret) {
+        String token = clientId + ":" + clientSecret;
+        String encodedString = Base64.getEncoder().encodeToString(token.getBytes());
+        return "Basic " + encodedString;
+    }
+}
--- a/oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/CallbackServlet.java
+++ b/oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/CallbackServlet.java
@ -4,10 +4,8 @@ import org.eclipse.microprofile.config.Config;

 import javax.inject.Inject;
 import javax.json.JsonObject;
-import javax.servlet.RequestDispatcher;
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
-import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.ws.rs.client.Client;
@ -18,10 +16,9 @@ import javax.ws.rs.core.Form;
 import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.MediaType;
 import java.io.IOException;
-import java.util.Base64;

@WebServlet(urlPatterns = "/callback")
-public class CallbackServlet extends HttpServlet {
+public class CallbackServlet extends AbstractServlet {

    @Inject
    private Config config;
@ -29,6 +26,9 @@ public class CallbackServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

+        String clientId = config.getValue("client.clientId", String.class);
+        String clientSecret = config.getValue("client.clientSecret", String.class);
+
        //Error:
        String error = request.getParameter("error");
        if (error != null) {
@ -53,24 +53,15 @@ public class CallbackServlet extends HttpServlet {
        form.param("code", code);
        form.param("redirect_uri", config.getValue("client.redirectUri", String.class));

-        JsonObject tokenResponse = target.request(MediaType.APPLICATION_JSON_TYPE)
-                .header(HttpHeaders.AUTHORIZATION, getAuthorizationHeaderValue())
-                .post(Entity.entity(form, MediaType.APPLICATION_FORM_URLENCODED_TYPE), JsonObject.class);
-
-        request.getSession().setAttribute("tokenResponse", tokenResponse);
+        try {
+            JsonObject tokenResponse = target.request(MediaType.APPLICATION_JSON_TYPE)
+                    .header(HttpHeaders.AUTHORIZATION, getAuthorizationHeaderValue(clientId, clientSecret))
+                    .post(Entity.entity(form, MediaType.APPLICATION_FORM_URLENCODED_TYPE), JsonObject.class);
+            request.getSession().setAttribute("tokenResponse", tokenResponse);
+        } catch (Exception ex) {
+            System.out.println(ex.getMessage());
+            request.setAttribute("error", ex.getMessage());
+        }
        dispatch("/", request, response);
    }
-
-    private void dispatch(String location, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
-        RequestDispatcher requestDispatcher = request.getRequestDispatcher(location);
-        requestDispatcher.forward(request, response);
-    }
-
-    private String getAuthorizationHeaderValue() {
-        String clientId = config.getValue("client.clientId", String.class);
-        String clientSecret = config.getValue("client.clientSecret", String.class);
-        String token = clientId + ":" + clientSecret;
-        String encodedString = Base64.getEncoder().encodeToString(token.getBytes());
-        return "Basic " + encodedString;
-    }
 }
--- a/oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/RefreshTokenServlet.java
+++ b/oauth2-framework-impl/oauth2-client/src/main/java/com/baeldung/oauth2/client/RefreshTokenServlet.java
@ -0,0 +1,57 @@
+package com.baeldung.oauth2.client;
+
+import org.eclipse.microprofile.config.Config;
+
+import javax.inject.Inject;
+import javax.json.JsonObject;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.ws.rs.client.Client;
+import javax.ws.rs.client.ClientBuilder;
+import javax.ws.rs.client.Entity;
+import javax.ws.rs.client.WebTarget;
+import javax.ws.rs.core.Form;
+import javax.ws.rs.core.HttpHeaders;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+import java.io.IOException;
+
+@WebServlet(urlPatterns = "/refreshtoken")
+public class RefreshTokenServlet extends AbstractServlet {
+
+    @Inject
+    private Config config;
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+        String clientId = config.getValue("client.clientId", String.class);
+        String clientSecret = config.getValue("client.clientSecret", String.class);
+
+        JsonObject actualTokenResponse = (JsonObject) request.getSession().getAttribute("tokenResponse");
+        Client client = ClientBuilder.newClient();
+        WebTarget target = client.target(config.getValue("provider.tokenUri", String.class));
+
+        Form form = new Form();
+        form.param("grant_type", "refresh_token");
+        form.param("refresh_token", actualTokenResponse.getString("refresh_token"));
+
+        String scope = request.getParameter("scope");
+        if (scope != null && !scope.isEmpty()) {
+            form.param("scope", scope);
+        }
+
+        Response jaxrsResponse = target.request(MediaType.APPLICATION_JSON_TYPE)
+                .header(HttpHeaders.AUTHORIZATION, getAuthorizationHeaderValue(clientId, clientSecret))
+                .post(Entity.entity(form, MediaType.APPLICATION_FORM_URLENCODED_TYPE), Response.class);
+        JsonObject tokenResponse = jaxrsResponse.readEntity(JsonObject.class);
+        if (jaxrsResponse.getStatus() == 200) {
+            request.getSession().setAttribute("tokenResponse", tokenResponse);
+        } else {
+            request.setAttribute("error", tokenResponse.getString("error_description", "error!"));
+        }
+        dispatch("/", request, response);
+    }
+}
--- a/oauth2-framework-impl/oauth2-client/src/main/webapp/index.jsp
+++ b/oauth2-framework-impl/oauth2-client/src/main/webapp/index.jsp
@ -10,6 +10,7 @@
        body {
            margin: 0px;
        }
+
        input[type=text], input[type=password] {
            width: 75%;
            padding: 4px 0px;
@ -17,6 +18,7 @@
            border: 1px solid #502bcc;
            box-sizing: border-box;
        }
+
        .container-error {
            padding: 16px;
            border: 1px solid #cc102a;
@ -25,6 +27,7 @@
            margin-left: 25px;
            margin-bottom: 25px;
        }
+
        .container {
            padding: 16px;
            border: 1px solid #130ecc;
@ -81,8 +84,20 @@
        <li>access_token: ${tokenResponse.getString("access_token")}</li>
        <li>scope: ${tokenResponse.getString("scope")}</li>
        <li>Expires in (s): ${tokenResponse.getInt("expires_in")}</li>
+        <li>refresh_token: ${tokenResponse.getString("refresh_token")}</li>
    </ul>
 </div>
+
+<div class="container">
+    <span><h4>Refresh Token</h4></span>
+    <hr>
+    <ul>
+        <li><a href="refreshtoken">Refresh token (original scope)</a></li>
+        <li><a href="refreshtoken?scope=resource.read">Refresh token (scope: resource.read)</a></li>
+        <li><a href="refreshtoken?scope=resource.write">Refresh token (scope: resource.write)</a></li>
+    </ul>
+</div>
+
 <div class="container">
    <span><h4>OAuth2 Resource Server Call</h4></span>
    <hr>
@ -90,7 +105,6 @@
        <li><a href="downstream?action=read">Read Protected Resource</a></li>
        <li><a href="downstream?action=write">Write Protected Resource</a></li>
    </ul>
-
 </div>

 </body>
--- a/parent-boot-performance/README.md
+++ b/parent-boot-performance/README.md
@ -1 +0,0 @@
-This is a parent module for projects that want to take advantage of the latest Spring Boot improvements/features.
--- a/parent-boot-performance/pom.xml
+++ b/parent-boot-performance/pom.xml
@ -1,92 +0,0 @@
-<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>parent-boot-performance</artifactId>
-    <version>0.0.1-SNAPSHOT</version>
-    <name>parent-boot-performance</name>
-    <packaging>pom</packaging>
-    <description>Parent for all modules that want to take advantage of the latest Spring Boot improvements/features. Current version: 2.2</description>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <dependencyManagement>
-        <dependencies>
-            <dependency>
-                <groupId>org.springframework.boot</groupId>
-                <artifactId>spring-boot-dependencies</artifactId>
-                <version>${spring-boot.version}</version>
-                <type>pom</type>
-                <scope>import</scope>
-            </dependency>
-        </dependencies>
-    </dependencyManagement>
-	
-    <dependencies>
-        <dependency>
-            <groupId>io.rest-assured</groupId>
-            <artifactId>rest-assured</artifactId>
-            </dependency>
-        <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-starter-test</artifactId>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
-    <build>
-        <pluginManagement>
-            <plugins>
-                <plugin>
-                    <groupId>org.springframework.boot</groupId>
-                    <artifactId>spring-boot-maven-plugin</artifactId>
-                    <version>${spring-boot.version}</version>
-                    <configuration>
-                        <mainClass>${start-class}</mainClass>
-                        <!-- this is necessary as we're not using the Boot parent -->
-                    </configuration>
-                </plugin>
-            </plugins>
-        </pluginManagement>
-    </build>
-    
-    <repositories>
-        <repository>
-            <id>spring-milestones</id>
-            <name>Spring Milestones</name>
-            <url>https://repo.spring.io/milestone</url>
-        </repository>
-    </repositories>
-    
-    <profiles>
-        <profile>
-            <id>thin-jar</id>
-            <build>
-                <plugins>
-                    <plugin>
-                        <groupId>org.springframework.boot</groupId>
-                        <artifactId>spring-boot-maven-plugin</artifactId>
-                        <dependencies>
-                            <!-- The following enables the "thin jar" deployment option. -->
-                            <dependency>
-                                <groupId>org.springframework.boot.experimental</groupId>
-                                <artifactId>spring-boot-thin-layout</artifactId>
-                                <version>${thin.version}</version>
-                            </dependency>
-                        </dependencies>
-                    </plugin>
-                </plugins>
-            </build>
-        </profile>
-    </profiles>
-
-    <properties>
-        <rest-assured.version>3.1.0</rest-assured.version>
-        <!-- plugins -->
-        <thin.version>1.0.21.RELEASE</thin.version>
-        <spring-boot.version>2.2.0.M3</spring-boot.version>
-    </properties>
-</project>
--- a/parent-java/README.md
+++ b/parent-java/README.md
@ -1 +1 @@
-## Relevant articles:
+## Relevant Articles:
--- a/parent-spring-4/README.md
+++ b/parent-spring-4/README.md
@ -1 +1 @@
-## Relevant articles:
+## Relevant Articles:
--- a/parent-spring-5/README.md
+++ b/parent-spring-5/README.md
@ -1 +1 @@
-## Relevant articles:
+## Relevant Articles:
--- a/persistence-modules/jpa-hibernate-cascade-type/pom.xml
+++ b/persistence-modules/jpa-hibernate-cascade-type/pom.xml
@ -2,10 +2,6 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <artifactId>jpa-hibernate-cascade-type</artifactId>
-    <modelVersion>4.0.0</modelVersion>
-    <version>1.0.0-SNAPSHOT</version>
-	
    <parent>
        <groupId>com.baeldung</groupId>
        <artifactId>parent-modules</artifactId>
@ -13,6 +9,10 @@
        <relativePath>../../</relativePath>
    </parent>

+    <artifactId>jpa-hibernate-cascade-type</artifactId>
+    <modelVersion>4.0.0</modelVersion>
+    <version>1.0.0-SNAPSHOT</version>
+
    <dependencies>
        <dependency>
            <groupId>org.hibernate</groupId>
--- a/persistence-modules/pom.xml
+++ b/persistence-modules/pom.xml
@ -58,5 +58,6 @@
        <module>spring-jpa</module>
        <module>spring-persistence-simple</module>
        <module>jpa-hibernate-cascade-type</module>
+				<module>r2dbc</module>
    </modules>
 </project>
--- a/persistence-modules/r2dbc/.gitignore
+++ b/persistence-modules/r2dbc/.gitignore
@ -0,0 +1,31 @@
+HELP.md
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**
+!**/src/test/**
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+
+### VS Code ###
+.vscode/
--- a/persistence-modules/r2dbc/.mvn/wrapper/MavenWrapperDownloader.java
+++ b/persistence-modules/r2dbc/.mvn/wrapper/MavenWrapperDownloader.java
@ -0,0 +1,114 @@
+/*
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you under the Apache License, Version 2.0 (the
+"License"); you may not use this file except in compliance
+with the License.  You may obtain a copy of the License at
+
+  https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing,
+software distributed under the License is distributed on an
+"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, either express or implied.  See the License for the
+specific language governing permissions and limitations
+under the License.
+*/
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.net.URL;
+import java.nio.channels.Channels;
+import java.nio.channels.ReadableByteChannel;
+import java.util.Properties;
+
+public class MavenWrapperDownloader {
+
+    /**
+     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
+     */
+    private static final String DEFAULT_DOWNLOAD_URL =
+            "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.4.2/maven-wrapper-0.4.2.jar";
+
+    /**
+     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
+     * use instead of the default one.
+     */
+    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
+            ".mvn/wrapper/maven-wrapper.properties";
+
+    /**
+     * Path where the maven-wrapper.jar will be saved to.
+     */
+    private static final String MAVEN_WRAPPER_JAR_PATH =
+            ".mvn/wrapper/maven-wrapper.jar";
+
+    /**
+     * Name of the property which should be used to override the default download url for the wrapper.
+     */
+    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
+
+    public static void main(String args[]) {
+        System.out.println("- Downloader started");
+        File baseDirectory = new File(args[0]);
+        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
+
+        // If the maven-wrapper.properties exists, read it and check if it contains a custom
+        // wrapperUrl parameter.
+        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
+        String url = DEFAULT_DOWNLOAD_URL;
+        if(mavenWrapperPropertyFile.exists()) {
+            FileInputStream mavenWrapperPropertyFileInputStream = null;
+            try {
+                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
+                Properties mavenWrapperProperties = new Properties();
+                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
+                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
+            } catch (IOException e) {
+                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
+            } finally {
+                try {
+                    if(mavenWrapperPropertyFileInputStream != null) {
+                        mavenWrapperPropertyFileInputStream.close();
+                    }
+                } catch (IOException e) {
+                    // Ignore ...
+                }
+            }
+        }
+        System.out.println("- Downloading from: : " + url);
+
+        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
+        if(!outputFile.getParentFile().exists()) {
+            if(!outputFile.getParentFile().mkdirs()) {
+                System.out.println(
+                        "- ERROR creating output direcrory '" + outputFile.getParentFile().getAbsolutePath() + "'");
+            }
+        }
+        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
+        try {
+            downloadFileFromURL(url, outputFile);
+            System.out.println("Done");
+            System.exit(0);
+        } catch (Throwable e) {
+            System.out.println("- Error downloading");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
+        URL website = new URL(urlString);
+        ReadableByteChannel rbc;
+        rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(destination);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        fos.close();
+        rbc.close();
+    }
+
+}
--- a/persistence-modules/r2dbc/.mvn/wrapper/maven-wrapper.jar
+++ b/persistence-modules/r2dbc/.mvn/wrapper/maven-wrapper.jar
--- a/persistence-modules/r2dbc/.mvn/wrapper/maven-wrapper.properties
+++ b/persistence-modules/r2dbc/.mvn/wrapper/maven-wrapper.properties
@ -0,0 +1 @@
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.0/apache-maven-3.6.0-bin.zip
--- a/persistence-modules/r2dbc/README.md
+++ b/persistence-modules/r2dbc/README.md
@ -0,0 +1,3 @@
+### Relevant Articles:
+- [R2DBC – Reactive Relational Database Connectivity](https://www.baeldung.com/r2dbc)
+
--- a/persistence-modules/r2dbc/mvnw
+++ b/persistence-modules/r2dbc/mvnw
@ -0,0 +1,286 @@
+#!/bin/sh
+# ----------------------------------------------------------------------------
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#    https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+# ----------------------------------------------------------------------------
+
+# ----------------------------------------------------------------------------
+# Maven2 Start Up Batch script
+#
+# Required ENV vars:
+# ------------------
+#   JAVA_HOME - location of a JDK home dir
+#
+# Optional ENV vars
+# -----------------
+#   M2_HOME - location of maven2's installed home dir
+#   MAVEN_OPTS - parameters passed to the Java VM when running Maven
+#     e.g. to debug Maven itself, use
+#       set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+#   MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+# ----------------------------------------------------------------------------
+
+if [ -z "$MAVEN_SKIP_RC" ] ; then
+
+  if [ -f /etc/mavenrc ] ; then
+    . /etc/mavenrc
+  fi
+
+  if [ -f "$HOME/.mavenrc" ] ; then
+    . "$HOME/.mavenrc"
+  fi
+
+fi
+
+# OS specific support.  $var _must_ be set to either true or false.
+cygwin=false;
+darwin=false;
+mingw=false
+case "`uname`" in
+  CYGWIN*) cygwin=true ;;
+  MINGW*) mingw=true;;
+  Darwin*) darwin=true
+    # Use /usr/libexec/java_home if available, otherwise fall back to /Library/Java/Home
+    # See https://developer.apple.com/library/mac/qa/qa1170/_index.html
+    if [ -z "$JAVA_HOME" ]; then
+      if [ -x "/usr/libexec/java_home" ]; then
+        export JAVA_HOME="`/usr/libexec/java_home`"
+      else
+        export JAVA_HOME="/Library/Java/Home"
+      fi
+    fi
+    ;;
+esac
+
+if [ -z "$JAVA_HOME" ] ; then
+  if [ -r /etc/gentoo-release ] ; then
+    JAVA_HOME=`java-config --jre-home`
+  fi
+fi
+
+if [ -z "$M2_HOME" ] ; then
+  ## resolve links - $0 may be a link to maven's home
+  PRG="$0"
+
+  # need this for relative symlinks
+  while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+      PRG="$link"
+    else
+      PRG="`dirname "$PRG"`/$link"
+    fi
+  done
+
+  saveddir=`pwd`
+
+  M2_HOME=`dirname "$PRG"`/..
+
+  # make it fully qualified
+  M2_HOME=`cd "$M2_HOME" && pwd`
+
+  cd "$saveddir"
+  # echo Using m2 at $M2_HOME
+fi
+
+# For Cygwin, ensure paths are in UNIX format before anything is touched
+if $cygwin ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --unix "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
+fi
+
+# For Mingw, ensure paths are in UNIX format before anything is touched
+if $mingw ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME="`(cd "$M2_HOME"; pwd)`"
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME="`(cd "$JAVA_HOME"; pwd)`"
+  # TODO classpath?
+fi
+
+if [ -z "$JAVA_HOME" ]; then
+  javaExecutable="`which javac`"
+  if [ -n "$javaExecutable" ] && ! [ "`expr \"$javaExecutable\" : '\([^ ]*\)'`" = "no" ]; then
+    # readlink(1) is not available as standard on Solaris 10.
+    readLink=`which readlink`
+    if [ ! `expr "$readLink" : '\([^ ]*\)'` = "no" ]; then
+      if $darwin ; then
+        javaHome="`dirname \"$javaExecutable\"`"
+        javaExecutable="`cd \"$javaHome\" && pwd -P`/javac"
+      else
+        javaExecutable="`readlink -f \"$javaExecutable\"`"
+      fi
+      javaHome="`dirname \"$javaExecutable\"`"
+      javaHome=`expr "$javaHome" : '\(.*\)/bin'`
+      JAVA_HOME="$javaHome"
+      export JAVA_HOME
+    fi
+  fi
+fi
+
+if [ -z "$JAVACMD" ] ; then
+  if [ -n "$JAVA_HOME"  ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+      # IBM's JDK on AIX uses strange locations for the executables
+      JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+      JAVACMD="$JAVA_HOME/bin/java"
+    fi
+  else
+    JAVACMD="`which java`"
+  fi
+fi
+
+if [ ! -x "$JAVACMD" ] ; then
+  echo "Error: JAVA_HOME is not defined correctly." >&2
+  echo "  We cannot execute $JAVACMD" >&2
+  exit 1
+fi
+
+if [ -z "$JAVA_HOME" ] ; then
+  echo "Warning: JAVA_HOME environment variable is not set."
+fi
+
+CLASSWORLDS_LAUNCHER=org.codehaus.plexus.classworlds.launcher.Launcher
+
+# traverses directory structure from process work directory to filesystem root
+# first directory with .mvn subdirectory is considered project base directory
+find_maven_basedir() {
+
+  if [ -z "$1" ]
+  then
+    echo "Path not specified to find_maven_basedir"
+    return 1
+  fi
+
+  basedir="$1"
+  wdir="$1"
+  while [ "$wdir" != '/' ] ; do
+    if [ -d "$wdir"/.mvn ] ; then
+      basedir=$wdir
+      break
+    fi
+    # workaround for JBEAP-8937 (on Solaris 10/Sparc)
+    if [ -d "${wdir}" ]; then
+      wdir=`cd "$wdir/.."; pwd`
+    fi
+    # end of workaround
+  done
+  echo "${basedir}"
+}
+
+# concatenates all lines of a file
+concat_lines() {
+  if [ -f "$1" ]; then
+    echo "$(tr -s '\n' ' ' < "$1")"
+  fi
+}
+
+BASE_DIR=`find_maven_basedir "$(pwd)"`
+if [ -z "$BASE_DIR" ]; then
+  exit 1;
+fi
+
+##########################################################################################
+# Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+# This allows using the maven wrapper in projects that prohibit checking in binary data.
+##########################################################################################
+if [ -r "$BASE_DIR/.mvn/wrapper/maven-wrapper.jar" ]; then
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Found .mvn/wrapper/maven-wrapper.jar"
+    fi
+else
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Couldn't find .mvn/wrapper/maven-wrapper.jar, downloading it ..."
+    fi
+    jarUrl="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.4.2/maven-wrapper-0.4.2.jar"
+    while IFS="=" read key value; do
+      case "$key" in (wrapperUrl) jarUrl="$value"; break ;;
+      esac
+    done < "$BASE_DIR/.mvn/wrapper/maven-wrapper.properties"
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Downloading from: $jarUrl"
+    fi
+    wrapperJarPath="$BASE_DIR/.mvn/wrapper/maven-wrapper.jar"
+
+    if command -v wget > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found wget ... using wget"
+        fi
+        wget "$jarUrl" -O "$wrapperJarPath"
+    elif command -v curl > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found curl ... using curl"
+        fi
+        curl -o "$wrapperJarPath" "$jarUrl"
+    else
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Falling back to using Java to download"
+        fi
+        javaClass="$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.java"
+        if [ -e "$javaClass" ]; then
+            if [ ! -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Compiling MavenWrapperDownloader.java ..."
+                fi
+                # Compiling the Java class
+                ("$JAVA_HOME/bin/javac" "$javaClass")
+            fi
+            if [ -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                # Running the downloader
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Running MavenWrapperDownloader.java ..."
+                fi
+                ("$JAVA_HOME/bin/java" -cp .mvn/wrapper MavenWrapperDownloader "$MAVEN_PROJECTBASEDIR")
+            fi
+        fi
+    fi
+fi
+##########################################################################################
+# End of extension
+##########################################################################################
+
+export MAVEN_PROJECTBASEDIR=${MAVEN_BASEDIR:-"$BASE_DIR"}
+if [ "$MVNW_VERBOSE" = true ]; then
+  echo $MAVEN_PROJECTBASEDIR
+fi
+MAVEN_OPTS="$(concat_lines "$MAVEN_PROJECTBASEDIR/.mvn/jvm.config") $MAVEN_OPTS"
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --path --windows "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --path --windows "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
+  [ -n "$MAVEN_PROJECTBASEDIR" ] &&
+    MAVEN_PROJECTBASEDIR=`cygpath --path --windows "$MAVEN_PROJECTBASEDIR"`
+fi
+
+WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+exec "$JAVACMD" \
+  $MAVEN_OPTS \
+  -classpath "$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.jar" \
+  "-Dmaven.home=${M2_HOME}" "-Dmaven.multiModuleProjectDirectory=${MAVEN_PROJECTBASEDIR}" \
+  ${WRAPPER_LAUNCHER} $MAVEN_CONFIG "$@"
--- a/persistence-modules/r2dbc/mvnw.cmd
+++ b/persistence-modules/r2dbc/mvnw.cmd
@ -0,0 +1,161 @@
+@REM ----------------------------------------------------------------------------
+@REM Licensed to the Apache Software Foundation (ASF) under one
+@REM or more contributor license agreements.  See the NOTICE file
+@REM distributed with this work for additional information
+@REM regarding copyright ownership.  The ASF licenses this file
+@REM to you under the Apache License, Version 2.0 (the
+@REM "License"); you may not use this file except in compliance
+@REM with the License.  You may obtain a copy of the License at
+@REM
+@REM    https://www.apache.org/licenses/LICENSE-2.0
+@REM
+@REM Unless required by applicable law or agreed to in writing,
+@REM software distributed under the License is distributed on an
+@REM "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+@REM KIND, either express or implied.  See the License for the
+@REM specific language governing permissions and limitations
+@REM under the License.
+@REM ----------------------------------------------------------------------------
+
+@REM ----------------------------------------------------------------------------
+@REM Maven2 Start Up Batch script
+@REM
+@REM Required ENV vars:
+@REM JAVA_HOME - location of a JDK home dir
+@REM
+@REM Optional ENV vars
+@REM M2_HOME - location of maven2's installed home dir
+@REM MAVEN_BATCH_ECHO - set to 'on' to enable the echoing of the batch commands
+@REM MAVEN_BATCH_PAUSE - set to 'on' to wait for a key stroke before ending
+@REM MAVEN_OPTS - parameters passed to the Java VM when running Maven
+@REM     e.g. to debug Maven itself, use
+@REM set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+@REM MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+@REM ----------------------------------------------------------------------------
+
+@REM Begin all REM lines with '@' in case MAVEN_BATCH_ECHO is 'on'
+@echo off
+@REM set title of command window
+title %0
+@REM enable echoing my setting MAVEN_BATCH_ECHO to 'on'
+@if "%MAVEN_BATCH_ECHO%" == "on"  echo %MAVEN_BATCH_ECHO%
+
+@REM set %HOME% to equivalent of $HOME
+if "%HOME%" == "" (set "HOME=%HOMEDRIVE%%HOMEPATH%")
+
+@REM Execute a user defined script before this one
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPre
+@REM check for pre script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_pre.bat" call "%HOME%\mavenrc_pre.bat"
+if exist "%HOME%\mavenrc_pre.cmd" call "%HOME%\mavenrc_pre.cmd"
+:skipRcPre
+
+@setlocal
+
+set ERROR_CODE=0
+
+@REM To isolate internal variables from possible post scripts, we use another setlocal
+@setlocal
+
+@REM ==== START VALIDATION ====
+if not "%JAVA_HOME%" == "" goto OkJHome
+
+echo.
+echo Error: JAVA_HOME not found in your environment. >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+:OkJHome
+if exist "%JAVA_HOME%\bin\java.exe" goto init
+
+echo.
+echo Error: JAVA_HOME is set to an invalid directory. >&2
+echo JAVA_HOME = "%JAVA_HOME%" >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+@REM ==== END VALIDATION ====
+
+:init
+
+@REM Find the project base dir, i.e. the directory that contains the folder ".mvn".
+@REM Fallback to current working directory if not found.
+
+set MAVEN_PROJECTBASEDIR=%MAVEN_BASEDIR%
+IF NOT "%MAVEN_PROJECTBASEDIR%"=="" goto endDetectBaseDir
+
+set EXEC_DIR=%CD%
+set WDIR=%EXEC_DIR%
+:findBaseDir
+IF EXIST "%WDIR%"\.mvn goto baseDirFound
+cd ..
+IF "%WDIR%"=="%CD%" goto baseDirNotFound
+set WDIR=%CD%
+goto findBaseDir
+
+:baseDirFound
+set MAVEN_PROJECTBASEDIR=%WDIR%
+cd "%EXEC_DIR%"
+goto endDetectBaseDir
+
+:baseDirNotFound
+set MAVEN_PROJECTBASEDIR=%EXEC_DIR%
+cd "%EXEC_DIR%"
+
+:endDetectBaseDir
+
+IF NOT EXIST "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" goto endReadAdditionalConfig
+
+@setlocal EnableExtensions EnableDelayedExpansion
+for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do set JVM_CONFIG_MAVEN_PROPS=!JVM_CONFIG_MAVEN_PROPS! %%a
+@endlocal & set JVM_CONFIG_MAVEN_PROPS=%JVM_CONFIG_MAVEN_PROPS%
+
+:endReadAdditionalConfig
+
+SET MAVEN_JAVA_EXE="%JAVA_HOME%\bin\java.exe"
+set WRAPPER_JAR="%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.jar"
+set WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+set DOWNLOAD_URL="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.4.2/maven-wrapper-0.4.2.jar"
+FOR /F "tokens=1,2 delims==" %%A IN (%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.properties) DO (
+	IF "%%A"=="wrapperUrl" SET DOWNLOAD_URL=%%B 
+)
+
+@REM Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+@REM This allows using the maven wrapper in projects that prohibit checking in binary data.
+if exist %WRAPPER_JAR% (
+    echo Found %WRAPPER_JAR%
+) else (
+    echo Couldn't find %WRAPPER_JAR%, downloading it ...
+	echo Downloading from: %DOWNLOAD_URL%
+    powershell -Command "(New-Object Net.WebClient).DownloadFile('%DOWNLOAD_URL%', '%WRAPPER_JAR%')"
+    echo Finished downloading %WRAPPER_JAR%
+)
+@REM End of extension
+
+%MAVEN_JAVA_EXE% %JVM_CONFIG_MAVEN_PROPS% %MAVEN_OPTS% %MAVEN_DEBUG_OPTS% -classpath %WRAPPER_JAR% "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" %WRAPPER_LAUNCHER% %MAVEN_CONFIG% %*
+if ERRORLEVEL 1 goto error
+goto end
+
+:error
+set ERROR_CODE=1
+
+:end
+@endlocal & set ERROR_CODE=%ERROR_CODE%
+
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPost
+@REM check for post script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_post.bat" call "%HOME%\mavenrc_post.bat"
+if exist "%HOME%\mavenrc_post.cmd" call "%HOME%\mavenrc_post.cmd"
+:skipRcPost
+
+@REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
+if "%MAVEN_BATCH_PAUSE%" == "on" pause
+
+if "%MAVEN_TERMINATE_CMD%" == "on" exit %ERROR_CODE%
+
+exit /B %ERROR_CODE%
--- a/persistence-modules/r2dbc/pom.xml
+++ b/persistence-modules/r2dbc/pom.xml
@ -0,0 +1,90 @@
+<?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>
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.1.6.RELEASE</version>
+		<relativePath /> <!-- lookup parent from repository -->
+	</parent>
+	<groupId>org.baeldung.examples.r2dbc</groupId>
+	<artifactId>r2dbc-example</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>r2dbc-example</name>
+	<description>Sample R2DBC Project</description>
+
+	<properties>
+		<java.version>1.8</java.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-webflux</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>io.projectreactor</groupId>
+			<artifactId>reactor-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+
+
+		<!-- R2DBC H2 Driver -->
+		<dependency>
+			<groupId>io.r2dbc</groupId>
+			<artifactId>r2dbc-h2</artifactId>
+			<version>0.8.0.M8</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-configuration-processor</artifactId>
+			<optional>true</optional>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-devtools</artifactId>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+
+	<!-- Extra repositories for R2DBC-H2 -->
+	<repositories>
+
+		<repository>
+			<id>spring-snapshots</id>
+			<name>Spring Snapshots</name>
+			<url>https://repo.spring.io/snapshot</url>
+			<snapshots>
+				<enabled>true</enabled>
+			</snapshots>
+		</repository>
+
+		<repository>
+			<id>spring-milestones</id>
+			<name>Spring Milestones</name>
+			<url>https://repo.spring.io/milestone</url>
+			<snapshots>
+				<enabled>false</enabled>
+			</snapshots>
+		</repository>
+
+	</repositories>
+
+</project>
--- a/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/Account.java
+++ b/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/Account.java
@ -0,0 +1,68 @@
+package org.baeldung.examples.r2dbc;
+
+import java.math.BigDecimal;
+
+public class Account {
+
+    private Long id;
+    private String iban;
+    private BigDecimal balance;
+    
+    
+    public Account() {}
+    
+    public Account(Long id, String iban, BigDecimal balance) {
+        this.id = id;
+        this.iban = iban;
+        this.balance = balance;
+    }
+
+    public Account(Long id, String iban, Double balance) {
+        this.id = id;
+        this.iban = iban;
+        this.balance = new BigDecimal(balance);
+    }
+    
+    /**
+     * @return the id
+     */
+    public Long getId() {
+        return id;
+    }
+
+    /**
+     * @param id the id to set
+     */
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    /**
+     * @return the iban
+     */
+    public String getIban() {
+        return iban;
+    }
+
+    /**
+     * @param iban the iban to set
+     */
+    public void setIban(String iban) {
+        this.iban = iban;
+    }
+
+    /**
+     * @return the balance
+     */
+    public BigDecimal getBalance() {
+        return balance;
+    }
+
+    /**
+     * @param balance the balance to set
+     */
+    public void setBalance(BigDecimal balance) {
+        this.balance = balance;
+    }
+
+}
--- a/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/AccountResource.java
+++ b/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/AccountResource.java
@ -0,0 +1,56 @@
+/**
+ * 
+ */
+package org.baeldung.examples.r2dbc;
+
+import java.math.BigDecimal;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+import io.r2dbc.spi.Connection;
+import io.r2dbc.spi.ConnectionFactory;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+/**
+ * @author Philippe
+ *
+ */
+@RestController
+public class AccountResource {
+
+    private final ReactiveAccountDao accountDao;
+
+    public AccountResource(ReactiveAccountDao accountDao) {
+        this.accountDao = accountDao;
+    }
+
+    @GetMapping("/accounts/{id}")
+    public Mono<ResponseEntity<Account>> getAccount(@PathVariable("id") Long id) {
+
+        return accountDao.findById(id)
+          .map(acc -> new ResponseEntity<>(acc, HttpStatus.OK))
+          .switchIfEmpty(Mono.just(new ResponseEntity<>(null, HttpStatus.NOT_FOUND)));
+    }
+
+    @GetMapping("/accounts")
+    public Flux<Account> getAllAccounts() {
+        return accountDao.findAll();
+    }
+
+    @PostMapping("/accounts")
+    public Mono<ResponseEntity<Account>> postAccount(@RequestBody Account account) {
+        return accountDao.createAccount(account)
+          .map(acc -> new ResponseEntity<>(acc, HttpStatus.CREATED))
+          .log();
+    }
+
+}
--- a/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/DatasourceConfig.java
+++ b/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/DatasourceConfig.java
@ -0,0 +1,65 @@
+package org.baeldung.examples.r2dbc;
+
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.util.StringUtils;
+
+import io.netty.util.internal.StringUtil;
+import io.r2dbc.spi.ConnectionFactories;
+import io.r2dbc.spi.ConnectionFactory;
+import io.r2dbc.spi.ConnectionFactoryOptions;
+import io.r2dbc.spi.ConnectionFactoryOptions.Builder;
+import io.r2dbc.spi.Option;
+import reactor.core.publisher.Flux;
+
+import static io.r2dbc.spi.ConnectionFactoryOptions.*;
+
+
+@Configuration
+public class DatasourceConfig {
+    
+    @Bean
+    public ConnectionFactory connectionFactory(R2DBCConfigurationProperties properties) {
+        
+        ConnectionFactoryOptions baseOptions = ConnectionFactoryOptions.parse(properties.getUrl());
+        Builder ob = ConnectionFactoryOptions.builder().from(baseOptions);
+        if ( !StringUtil.isNullOrEmpty(properties.getUser())) {
+            ob = ob.option(USER, properties.getUser());
+        }
+
+        if ( !StringUtil.isNullOrEmpty(properties.getPassword())) {
+            ob = ob.option(PASSWORD, properties.getPassword());
+        }
+        
+        ConnectionFactory cf = ConnectionFactories.get(ob.build());
+        return cf;
+    }
+    
+
+    @Bean
+    public CommandLineRunner initDatabase(ConnectionFactory cf) {
+    
+        return (args) ->
+          Flux.from(cf.create())
+              .flatMap(c -> 
+                Flux.from(c.createBatch()
+                  .add("drop table if exists Account")
+                  .add("create table Account(" +
+                    "id IDENTITY(1,1)," +
+                    "iban varchar(80) not null," +
+                    "balance DECIMAL(18,2) not null)")
+                  .add("insert into Account(iban,balance)" +
+                    "values('BR430120980198201982',100.00)")
+                  .add("insert into Account(iban,balance)" +
+                    "values('BR430120998729871000',250.00)")
+                  .execute())
+                .doFinally((st) -> c.close())
+              )
+              .log()
+              .blockLast();
+    }
+
+
+}
+
--- a/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/R2DBCConfigurationProperties.java
+++ b/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/R2DBCConfigurationProperties.java
@ -0,0 +1,58 @@
+package org.baeldung.examples.r2dbc;
+
+import javax.validation.constraints.NotEmpty;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+@ConfigurationProperties(prefix = "r2dbc")
+public class R2DBCConfigurationProperties {
+
+    @NotEmpty
+    private String url;
+
+    private String user;
+    private String password;
+
+    /**
+     * @return the url
+     */
+    public String getUrl() {
+        return url;
+    }
+
+    /**
+     * @param url the url to set
+     */
+    public void setUrl(String url) {
+        this.url = url;
+    }
+
+    /**
+     * @return the user
+     */
+    public String getUser() {
+        return user;
+    }
+
+    /**
+     * @param user the user to set
+     */
+    public void setUser(String user) {
+        this.user = user;
+    }
+
+    /**
+     * @return the password
+     */
+    public String getPassword() {
+        return password;
+    }
+
+    /**
+     * @param password the password to set
+     */
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+}
--- a/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/R2dbcExampleApplication.java
+++ b/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/R2dbcExampleApplication.java
@ -0,0 +1,17 @@
+package org.baeldung.examples.r2dbc;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+
+@SpringBootApplication
+@EnableConfigurationProperties(R2DBCConfigurationProperties.class)
+public class R2dbcExampleApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(R2dbcExampleApplication.class, args);
+    }
+    
+    
+
+}
--- a/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/ReactiveAccountDao.java
+++ b/persistence-modules/r2dbc/src/main/java/org/baeldung/examples/r2dbc/ReactiveAccountDao.java
@ -0,0 +1,76 @@
+package org.baeldung.examples.r2dbc;
+
+import java.math.BigDecimal;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Component;
+
+import io.r2dbc.spi.Connection;
+import io.r2dbc.spi.ConnectionFactory;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+@Component
+public class ReactiveAccountDao {
+
+    private ConnectionFactory connectionFactory;
+
+    public ReactiveAccountDao(ConnectionFactory connectionFactory) {
+        this.connectionFactory = connectionFactory;
+    }
+
+    public Mono<Account> findById(long id) {
+
+        return Mono.from(connectionFactory.create())
+          .flatMap(c -> Mono.from(c.createStatement("select id,iban,balance from Account where id = $1")
+            .bind("$1", id)
+            .execute())
+             .doFinally((st) -> close(c)))
+          .map(result -> result.map((row, meta) -> 
+            new Account(row.get("id", Long.class),
+              row.get("iban", String.class),
+              row.get("balance", BigDecimal.class))))
+          .flatMap( p -> Mono.from(p));
+    }
+
+    public Flux<Account> findAll() {
+
+        return Mono.from(connectionFactory.create())
+            .flatMap((c) -> Mono.from(c.createStatement("select id,iban,balance from Account")
+                .execute())
+                .doFinally((st) -> close(c)))
+            .flatMapMany(result -> Flux.from(result.map((row, meta) -> {
+                Account acc = new Account();
+                acc.setId(row.get("id", Long.class));
+                acc.setIban(row.get("iban", String.class));
+                acc.setBalance(row.get("balance", BigDecimal.class));
+                return acc;
+            })));
+    }
+    
+    public Mono<Account> createAccount(Account account) {
+        
+        return Mono.from(connectionFactory.create())
+          .flatMap(c -> Mono.from(c.beginTransaction())
+            .then(Mono.from(c.createStatement("insert into Account(iban,balance) values($1,$2)")
+              .bind("$1", account.getIban())
+              .bind("$2", account.getBalance())
+              .returnGeneratedValues("id")
+              .execute()))
+            .map(result -> result.map((row, meta) -> 
+                new Account(row.get("id", Long.class),
+                  account.getIban(),
+                  account.getBalance())))
+            .flatMap(pub -> Mono.from(pub))
+            .delayUntil(r -> c.commitTransaction())
+            .doFinally((st) -> c.close()));
+        
+    }
+
+    private <T> Mono<T> close(Connection connection) {
+        return Mono.from(connection.close())
+          .then(Mono.empty());
+    }
+
+}
--- a/persistence-modules/r2dbc/src/main/resources/META-INF/additional-spring-configuration-metadata.json
+++ b/persistence-modules/r2dbc/src/main/resources/META-INF/additional-spring-configuration-metadata.json
@ -0,0 +1,5 @@
+{"properties": [{
+  "name": "r2dbc",
+  "type": "org.baeldung.examples.r2dbc.R2DBCConfigurationProperties",
+  "description": "R2DBC Connection properties"
+}]}
--- a/persistence-modules/r2dbc/src/main/resources/application.yml
+++ b/persistence-modules/r2dbc/src/main/resources/application.yml
@ -0,0 +1,13 @@
+spring:
+  application:
+    name: r2dbc-test
+    
+# R2DBC URL
+r2dbc:
+  url: r2dbc:h2:mem://./testdb
+  
+  
+  
+    
+    
+    
--- a/persistence-modules/r2dbc/src/test/java/org/baeldung/examples/r2dbc/R2dbcExampleApplicationTests.java
+++ b/persistence-modules/r2dbc/src/test/java/org/baeldung/examples/r2dbc/R2dbcExampleApplicationTests.java
@ -0,0 +1,102 @@
+package org.baeldung.examples.r2dbc;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+
+import java.util.List;
+
+import org.hamcrest.core.IsNull;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.reactive.server.WebTestClient;
+
+import io.r2dbc.spi.ConnectionFactory;
+import reactor.core.publisher.Flux;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+public class R2dbcExampleApplicationTests {
+    
+    
+    @Autowired
+    private WebTestClient webTestClient;
+    
+    @Autowired
+    ConnectionFactory cf;
+    
+    @Before
+    public void initDatabase() {
+        
+        Flux.from(cf.create())
+          .flatMap(c -> 
+            c.createBatch()
+              .add("drop table if exists Account")
+              .add("create table Account(id IDENTITY(1,1), iban varchar(80) not null, balance DECIMAL(18,2) not null)")
+              .add("insert into Account(iban,balance) values ( 'BR430120980198201982', 100.00 ) ")
+              .add("insert into Account(iban,balance) values ( 'BR430120998729871000', 250.00 ) ")
+              .execute()
+          )
+          .log()
+          .blockLast();
+    }
+
+    @Test
+    public void givenExistingAccountId_whenGetAccount_thenReturnExistingAccountInfo() {
+        
+        webTestClient
+          .get()
+          .uri("/accounts/1")
+          .accept(MediaType.APPLICATION_JSON)
+          .exchange()
+          .expectStatus()
+            .isOk()
+          .expectBody(Account.class)
+            .value((acc) -> {
+                assertThat(acc.getId(),is(1l));
+            });
+    }
+    
+    @Test
+    public void givenDatabaseHasSomeAccounts_whenGetAccount_thenReturnExistingAccounts() {
+        
+        webTestClient
+          .get()
+          .uri("/accounts")
+          .accept(MediaType.APPLICATION_JSON)
+          .exchange()
+          .expectStatus()
+            .isOk()
+          .expectBody(List.class)
+            .value((accounts) -> {
+                assertThat(accounts.size(),not(is(0)));
+            });
+    }
+    
+    
+    @Test
+    public void givenNewAccountData_whenPostAccount_thenReturnNewAccountInfo() {
+
+        webTestClient
+        .post()
+        .uri("/accounts")
+        .syncBody(new Account(null,"BR4303010298012098", 151.00 ))
+        .accept(MediaType.APPLICATION_JSON)
+        .exchange()
+        .expectStatus()
+          .is2xxSuccessful()
+        .expectBody(Account.class)
+          .value((acc) -> {
+              assertThat(acc.getId(),is(notNullValue()));
+          });
+        
+    }
+
+}
--- a/persistence-modules/r2dbc/src/test/resources/application.yml
+++ b/persistence-modules/r2dbc/src/test/resources/application.yml
@ -0,0 +1,6 @@
+# R2DBC Test configuration
+r2dbc:
+  url: r2dbc:h2:mem://./testdb
+  
+  
+  
--- a/persistence-modules/spring-data-jpa/README.md
+++ b/persistence-modules/spring-data-jpa/README.md
@ -10,7 +10,6 @@
 - [Spring Data Java 8 Support](http://www.baeldung.com/spring-data-java-8)
 - [A Simple Tagging Implementation with JPA](http://www.baeldung.com/jpa-tagging)
 - [Spring Data Composable Repositories](https://www.baeldung.com/spring-data-composable-repositories)
- [Auditing with JPA, Hibernate, and Spring Data JPA](https://www.baeldung.com/database-auditing-jpa)
 - [Query Entities by Dates and Times with Spring Data JPA](https://www.baeldung.com/spring-data-jpa-query-by-date)
 - [DDD Aggregates and @DomainEvents](https://www.baeldung.com/spring-data-ddd)
 - [Spring Data – CrudRepository save() Method](https://www.baeldung.com/spring-data-crud-repository-save)
--- a/persistence-modules/spring-hibernate4/README.md
+++ b/persistence-modules/spring-hibernate4/README.md
@ -10,6 +10,7 @@
 - [Hibernate: save, persist, update, merge, saveOrUpdate](http://www.baeldung.com/hibernate-save-persist-update-merge-saveorupdate)
 - [Eager/Lazy Loading In Hibernate](http://www.baeldung.com/hibernate-lazy-eager-loading)
 - [The DAO with Spring and Hibernate](http://www.baeldung.com/persistence-layer-with-spring-and-hibernate)
+- [Auditing with JPA, Hibernate, and Spring Data JPA](https://www.baeldung.com/database-auditing-jpa)

 ### Quick Start

--- a/persistence-modules/spring-hibernate4/src/main/java/com/baeldung/spring/PersistenceConfig.java
+++ b/persistence-modules/spring-hibernate4/src/main/java/com/baeldung/spring/PersistenceConfig.java
@ -47,7 +47,7 @@ import com.google.common.base.Preconditions;
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = { "com.baeldung.persistence" }, transactionManagerRef = "jpaTransactionManager")
@EnableJpaAuditing
-@PropertySource({ "classpath:persistence-mysql.properties" })
+@PropertySource({ "classpath:persistence-h2.properties" })
@ComponentScan({ "com.baeldung.persistence" })
 public class PersistenceConfig {

--- a/persistence-modules/spring-hibernate4/src/test/java/com/baeldung/persistence/audit/EnversFooBarAuditIntegrationTest.java
+++ b/persistence-modules/spring-hibernate4/src/test/java/com/baeldung/persistence/audit/EnversFooBarAuditIntegrationTest.java
@ -2,6 +2,7 @@ package com.baeldung.persistence.audit;

 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;

 import java.util.List;

@ -17,6 +18,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.test.context.support.AnnotationConfigContextLoader;
@ -29,6 +31,7 @@ import com.baeldung.spring.config.PersistenceTestConfig;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = { PersistenceTestConfig.class }, loader = AnnotationConfigContextLoader.class)
+@DirtiesContext(classMode = DirtiesContext.ClassMode.BEFORE_CLASS)
 public class EnversFooBarAuditIntegrationTest {

    private static Logger logger = LoggerFactory.getLogger(EnversFooBarAuditIntegrationTest.class);
--- a/pom.xml
+++ b/pom.xml
@ -392,6 +392,7 @@
                <!--<module>core-java-modules/core-java-9</module> --> <!-- We haven't upgraded to java 9. Fixing in BAEL-10841 -->
                <!--<module>core-java-modules/core-java-os</module> --> <!-- We haven't upgraded to java 9.-->
                <module>core-java-modules/core-java-arrays</module>
+                <module>core-java-modules/core-java-arrays-2</module>
                <module>core-java-modules/core-java-collections</module>
                <module>core-java-modules/core-java-collections-list</module>
                <module>core-java-modules/core-java-collections-list-2</module>
@ -482,7 +483,7 @@
                <module>jee-7</module> -->
 				<module>jee-7-security</module>
 				<module>jersey</module>
-				<module>JGit</module>
+				<module>jgit</module>
 				<module>jgroups</module>
 				<module>jhipster-5</module>
 				<module>jib</module>
@ -561,7 +562,7 @@
 				<module>tensorflow-java</module>
 				<module>spring-boot-flowable</module>
 				<module>spring-security-kerberos</module>
-
+				<module>oauth2-framework-impl</module>
 			</modules>

 		</profile>
@ -614,6 +615,7 @@
 				<module>spring-5-data-reactive</module>
 				<module>spring-5-mvc</module>
 				<module>spring-5-reactive</module>
+				<module>spring-5-reactive-2</module>
 				<module>spring-5-reactive-client</module>
 				<module>spring-5-reactive-oauth</module>
 				<module>spring-5-reactive-security</module>
@ -742,7 +744,7 @@
 				<module>spring-security-mvc-ldap</module>
 				<module>spring-security-mvc-login</module>
 				<module>spring-security-mvc-persisted-remember-me</module>
-				<module>spring-security-mvc-session</module>
+				<module>spring-security-mvc</module>
 				<module>spring-security-mvc-socket</module>
 				<module>spring-security-openid</module>
 				<!--<module>spring-security-react</module> --> <!-- fails on Travis, fails intermittently on the new Jenkins (01.12.2018) BAEL-10834 -->
@ -779,7 +781,7 @@
 				<module>testing-modules</module>

 				<module>twilio</module>
-				<module>Twitter4J</module>
+				<module>twitter4j</module>

 				<module>undertow</module>

@ -826,6 +828,7 @@
 				<module>spring-5</module>
 				<module>spring-5-data-reactive</module>
 				<module>spring-5-reactive</module>
+				<module>spring-5-reactive-2</module>
 				<module>spring-5-reactive-client</module>
 				<module>spring-5-reactive-security</module>
 				<module>spring-5-security</module>
@ -917,7 +920,7 @@
 				<module>spring-security-mvc-digest-auth</module>
 				<module>spring-security-mvc-ldap</module>
 				<module>spring-security-mvc-persisted-remember-me</module>
-				<module>spring-security-mvc-session</module>
+				<module>spring-security-mvc</module>
 				<module>spring-security-mvc-socket</module>
 				<module>spring-security-rest</module>
 				<module>spring-security-sso</module>
@ -1086,6 +1089,7 @@
 				<!--<module>core-java-modules/core-java-9</module> --> <!-- We haven't upgraded to java 9. Fixing in BAEL-10841 -->
 				<!--<module>core-java-modules/core-java-os</module> --> <!-- We haven't upgraded to java 9.-->
 				<module>core-java-modules/core-java-arrays</module>
+				<module>core-java-modules/core-java-arrays-2</module>
 				<module>core-java-modules/core-java-collections</module>
 				<module>core-java-modules/core-java-collections-list</module>
 				<module>core-java-modules/core-java-collections-list-2</module>
@ -1172,7 +1176,7 @@
                <module>jee-7</module> -->
 				<module>jee-7-security</module>
 				<module>jersey</module>
-				<module>JGit</module>
+				<module>jgit</module>
 				<module>jgroups</module>
 				<module>jhipster-5</module>
 				<module>jib</module>
@ -1242,6 +1246,7 @@
 				<module>rsocket</module>
 				<module>rxjava</module>
 				<module>rxjava-2</module>
+				<module>oauth2-framework-impl</module>

 			</modules>

@ -1286,6 +1291,7 @@
 				<module>spring-5-data-reactive</module>
 				<module>spring-5-mvc</module>
 				<module>spring-5-reactive</module>
+				<module>spring-5-reactive-2</module>
 				<module>spring-5-reactive-client</module>
 				<module>spring-5-reactive-oauth</module>
 				<module>spring-5-reactive-security</module>
@ -1408,7 +1414,7 @@
 				<module>spring-security-mvc-ldap</module>
 				<module>spring-security-mvc-login</module>
 				<module>spring-security-mvc-persisted-remember-me</module>
-				<module>spring-security-mvc-session</module>
+				<module>spring-security-mvc</module>
 				<module>spring-security-mvc-socket</module>
 				<module>spring-security-openid</module>
 				<!--<module>spring-security-react</module> --> <!-- fails on Travis, fails intermittently on the new Jenkins (01.12.2018) BAEL-10834 -->
@ -1445,7 +1451,7 @@
 				<module>testing-modules</module>

 				<module>twilio</module>
-				<module>Twitter4J</module>
+				<module>twitter4j</module>

 				<module>undertow</module>

--- a/quarkus/README.md
+++ b/quarkus/README.md
@ -1,3 +1,3 @@
-## Relevant articles:
+## Relevant Articles:

 - [Guide to QuarkusIO](https://www.baeldung.com/quarkus-io)
--- a/quarkus/src/test/java/com/baeldung/quarkus/HelloResourceUnitTest.java
+++ b/quarkus/src/test/java/com/baeldung/quarkus/HelloResourceUnitTest.java
@ -7,7 +7,7 @@ import static io.restassured.RestAssured.given;
 import static org.hamcrest.CoreMatchers.is;

@QuarkusTest
-public class HelloResourceTest {
+public class HelloResourceUnitTest {

    @Test
    public void testHelloEndpoint() {
--- a/quarkus/src/test/java/com/baeldung/quarkus/NativeHelloResourceIT.java
+++ b/quarkus/src/test/java/com/baeldung/quarkus/NativeHelloResourceIT.java
@ -3,7 +3,7 @@ package com.baeldung.quarkus;
 import io.quarkus.test.junit.SubstrateTest;

@SubstrateTest
-public class NativeHelloResourceIT extends HelloResourceTest {
+public class NativeHelloResourceIT extends HelloResourceUnitTest {

    // Execute the same tests but in native mode.
 }
--- a/resteasy/bin/README.md
+++ b/resteasy/bin/README.md
@ -1,6 +0,0 @@
-=========
-
-## A Guide to RESTEasy
-
-
-### Relevant Articles:
--- a/spring-5-mvc/README.md
+++ b/spring-5-mvc/README.md
@ -1,4 +1,3 @@
 ### Relevant Articles:
 - [Spring Boot and Kotlin](http://www.baeldung.com/spring-boot-kotlin)
 - [Spring MVC Streaming and SSE Request Processing](https://www.baeldung.com/spring-mvc-sse-streams)
- [Overview and Need for DelegatingFilterProxy in Spring](https://www.baeldung.com/spring-delegating-filter-proxy)
--- a/spring-5-mvc/pom.xml
+++ b/spring-5-mvc/pom.xml
@ -23,10 +23,6 @@
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
-        <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-starter-security</artifactId>
-        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
--- a/spring-5-mvc/src/main/java/com/baeldung/Spring5Application.java
+++ b/spring-5-mvc/src/main/java/com/baeldung/Spring5Application.java
@ -1,12 +1,8 @@
 package com.baeldung;

-import javax.servlet.Filter;
-
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration;
-import org.springframework.web.filter.DelegatingFilterProxy;
-import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

@SpringBootApplication( exclude = SecurityAutoConfiguration.class)
 public class Spring5Application {
@ -14,32 +10,4 @@ public class Spring5Application {
    public static void main(String[] args) {
        SpringApplication.run(Spring5Application.class, args);
    }
-
-    public static class ApplicationInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
-
-        @Override
-        protected Class<?>[] getRootConfigClasses() {
-            return null;
-        }
-
-        @Override
-        protected Class<?>[] getServletConfigClasses() {
-            // TODO Auto-generated method stub
-            return null;
-        }
-
-        @Override
-        protected String[] getServletMappings() {
-            // TODO Auto-generated method stub
-            return null;
-        }
-
-        @Override
-        protected javax.servlet.Filter[] getServletFilters() {
-            DelegatingFilterProxy delegateFilterProxy = new DelegatingFilterProxy();
-            delegateFilterProxy.setTargetBeanName("loggingFilter");
-            return new Filter[] { delegateFilterProxy };
-        }
-    }
-
 }
--- a/spring-5-mvc/src/main/webapp/WEB-INF/web.xml
+++ b/spring-5-mvc/src/main/webapp/WEB-INF/web.xml
@ -16,14 +16,5 @@
        <servlet-name>functional</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
-	<filter>
-		<filter-name>loggingFilter</filter-name>
-		<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
-	</filter>
-
-	<filter-mapping>
-		<filter-name>loggingFilter</filter-name>
-		<url-pattern>/*</url-pattern>
-	</filter-mapping>

 </web-app>
--- a/spring-5-reactive-2/.gitignore
+++ b/spring-5-reactive-2/.gitignore
@ -0,0 +1,12 @@
+#folders#
+.idea
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear
--- a/spring-5-reactive-2/README.md
+++ b/spring-5-reactive-2/README.md
@ -0,0 +1 @@
+## Spring 5 Reactive Project
--- a/spring-5-reactive-2/pom.xml
+++ b/spring-5-reactive-2/pom.xml
@ -0,0 +1,50 @@
+<?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>spring-5-reactive-2</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>spring-5-reactive-2</name>
+    <packaging>jar</packaging>
+    <description>spring 5 sample project about new features</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-boot-2</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-boot-2</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-webflux</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <configuration>
+                    <mainClass>com.baeldung.webclient.WebClientApplication</mainClass>
+                    <layout>JAR</layout>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>
--- a/spring-5-reactive-2/src/main/java/com/baeldung/webclient/Tweet.java
+++ b/spring-5-reactive-2/src/main/java/com/baeldung/webclient/Tweet.java
@ -0,0 +1,13 @@
+package com.baeldung.webclient;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class Tweet {
+    private String text;
+    private String username;
+}
--- a/spring-5-reactive-2/src/main/java/com/baeldung/webclient/TweetsSlowServiceController.java
+++ b/spring-5-reactive-2/src/main/java/com/baeldung/webclient/TweetsSlowServiceController.java
@ -0,0 +1,20 @@
+package com.baeldung.webclient;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.Arrays;
+import java.util.List;
+
+@RestController
+public class TweetsSlowServiceController {
+
+    @GetMapping("/slow-service-tweets")
+    private List<Tweet> getAllTweets() throws Exception {
+        Thread.sleep(2000L); // delay
+        return Arrays.asList(
+          new Tweet("RestTemplate rules", "@user1"),
+          new Tweet("WebClient is better", "@user2"),
+          new Tweet("OK, both are useful", "@user1"));
+    }
+}
--- a/spring-5-reactive-2/src/main/java/com/baeldung/webclient/WebClientApplication.java
+++ b/spring-5-reactive-2/src/main/java/com/baeldung/webclient/WebClientApplication.java
@ -0,0 +1,11 @@
+package com.baeldung.webclient;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class WebClientApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(WebClientApplication.class, args);
+    }
+}
--- a/spring-5-reactive-2/src/main/java/com/baeldung/webclient/WebController.java
+++ b/spring-5-reactive-2/src/main/java/com/baeldung/webclient/WebController.java
@ -0,0 +1,60 @@
+package com.baeldung.webclient;
+
+import lombok.Setter;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.client.RestTemplate;
+import org.springframework.web.reactive.function.client.WebClient;
+import reactor.core.publisher.Flux;
+
+import java.util.List;
+
+@Slf4j
+@RestController
+public class WebController {
+
+    private static final int DEFAULT_PORT = 8080;
+
+    @Setter
+    private int serverPort = DEFAULT_PORT;
+
+    @GetMapping("/tweets-blocking")
+    public List<Tweet> getTweetsBlocking() {
+        log.info("Starting BLOCKING Controller!");
+        final String uri = getSlowServiceUri();
+
+        RestTemplate restTemplate = new RestTemplate();
+        ResponseEntity<List<Tweet>> response = restTemplate.exchange(
+          uri, HttpMethod.GET, null,
+          new ParameterizedTypeReference<List<Tweet>>(){});
+
+        List<Tweet> result = response.getBody();
+        result.forEach(tweet -> log.info(tweet.toString()));
+        log.info("Exiting BLOCKING Controller!");
+        return result;
+    }
+
+    @GetMapping(value = "/tweets-non-blocking", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
+    public Flux<Tweet> getTweetsNonBlocking() {
+        log.info("Starting NON-BLOCKING Controller!");
+        Flux<Tweet> tweetFlux = WebClient.create()
+          .get()
+          .uri(getSlowServiceUri())
+          .retrieve()
+          .bodyToFlux(Tweet.class);
+
+        tweetFlux.subscribe(tweet -> log.info(tweet.toString()));
+        log.info("Exiting NON-BLOCKING Controller!");
+        return tweetFlux;
+    }
+
+    private String getSlowServiceUri() {
+        return "http://localhost:" + serverPort + "/slow-service-tweets";
+    }
+
+}
--- a/spring-5-reactive-2/src/test/java/com/baeldung/webclient/WebControllerIntegrationTest.java
+++ b/spring-5-reactive-2/src/test/java/com/baeldung/webclient/WebControllerIntegrationTest.java
@ -0,0 +1,51 @@
+package com.baeldung.webclient;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.web.server.LocalServerPort;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.reactive.server.WebTestClient;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, classes = WebClientApplication.class)
+public class WebControllerIntegrationTest {
+
+    @LocalServerPort
+    int randomServerPort;
+
+    @Autowired
+    private WebTestClient testClient;
+
+    @Autowired
+    private WebController webController;
+
+    @Before
+    public void setup() {
+        webController.setServerPort(randomServerPort);
+    }
+
+    @Test
+    public void whenEndpointWithBlockingClientIsCalled_thenThreeTweetsAreReceived() {
+        testClient.get()
+          .uri("/tweets-blocking")
+          .exchange()
+          .expectStatus()
+          .isOk()
+          .expectBodyList(Tweet.class)
+          .hasSize(3);
+    }
+
+    @Test
+    public void whenEndpointWithNonBlockingClientIsCalled_thenThreeTweetsAreReceived() {
+        testClient.get()
+          .uri("/tweets-non-blocking")
+          .exchange()
+          .expectStatus()
+          .isOk()
+          .expectBodyList(Tweet.class)
+          .hasSize(3);
+    }
+}
--- a/spring-5-reactive-client/README.md
+++ b/spring-5-reactive-client/README.md
@ -4,3 +4,4 @@
 The "REST With Spring" Classes: http://bit.ly/restwithspring

 ### Relevant Articles
+
--- a/Show More
+++ b/Show More
				`@ -1 +0,0 @@`
				`This is a parent module for projects that want to take advantage of the latest Spring Boot improvements/features.`
				`@ -0,0 +1 @@`
				`distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.0/apache-maven-3.6.0-bin.zip`