Merge pull request #1 from eugenp/master

merge from master changes into fork
2018-02-10 16:14:01 +01:00 · 2018-02-10 16:14:01 +01:00 · d65bac08f4
commit d65bac08f4
parent 8b8a6a6e54 87a36777db
172 changed files with 7038 additions and 204 deletions
--- a/.gitignore
+++ b/.gitignore
@ -43,3 +43,4 @@ spring-call-getters-using-reflection/.mvn/wrapper/maven-wrapper.properties
 spring-check-if-a-property-is-null/.mvn/wrapper/maven-wrapper.properties
 *.springBeans

+20171220-JMeter.csv
--- a/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/BFSMazeSolver.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/BFSMazeSolver.java
@ -0,0 +1,52 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+public class BFSMazeSolver {
+    private static final int[][] DIRECTIONS = { { 0, 1 }, { 1, 0 }, { 0, -1 }, { -1, 0 } };
+
+    public List<Coordinate> solve(Maze maze) {
+        LinkedList<Coordinate> nextToVisit = new LinkedList<>();
+        Coordinate start = maze.getEntry();
+        nextToVisit.add(start);
+
+        while (!nextToVisit.isEmpty()) {
+            Coordinate cur = nextToVisit.remove();
+
+            if (!maze.isValidLocation(cur.getX(), cur.getY()) || maze.isExplored(cur.getX(), cur.getY())) {
+                continue;
+            }
+
+            if (maze.isWall(cur.getX(), cur.getY())) {
+                maze.setVisited(cur.getX(), cur.getY(), true);
+                continue;
+            }
+
+            if (maze.isExit(cur.getX(), cur.getY())) {
+                return backtrackPath(cur);
+            }
+
+            for (int[] direction : DIRECTIONS) {
+                Coordinate coordinate = new Coordinate(cur.getX() + direction[0], cur.getY() + direction[1], cur);
+                nextToVisit.add(coordinate);
+                maze.setVisited(cur.getX(), cur.getY(), true);
+            }
+        }
+        return Collections.emptyList();
+    }
+
+    private List<Coordinate> backtrackPath(Coordinate cur) {
+        List<Coordinate> path = new ArrayList<>();
+        Coordinate iter = cur;
+
+        while (iter != null) {
+            path.add(iter);
+            iter = iter.parent;
+        }
+
+        return path;
+    }
+}
--- a/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/Coordinate.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/Coordinate.java
@ -0,0 +1,31 @@
+package com.baeldung.algorithms.maze.solver;
+
+public class Coordinate {
+    int x;
+    int y;
+    Coordinate parent;
+
+    public Coordinate(int x, int y) {
+        this.x = x;
+        this.y = y;
+        this.parent = null;
+    }
+
+    public Coordinate(int x, int y, Coordinate parent) {
+        this.x = x;
+        this.y = y;
+        this.parent = parent;
+    }
+
+    int getX() {
+        return x;
+    }
+
+    int getY() {
+        return y;
+    }
+
+    Coordinate getParent() {
+        return parent;
+    }
+}
--- a/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/DFSMazeSolver.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/DFSMazeSolver.java
@ -0,0 +1,48 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class DFSMazeSolver {
+    private static final int[][] DIRECTIONS = { { 0, 1 }, { 1, 0 }, { 0, -1 }, { -1, 0 } };
+
+    public List<Coordinate> solve(Maze maze) {
+        List<Coordinate> path = new ArrayList<>();
+        if (explore(maze, maze.getEntry()
+            .getX(),
+            maze.getEntry()
+                .getY(),
+            path)) {
+            return path;
+        }
+        return Collections.emptyList();
+    }
+
+    private boolean explore(Maze maze, int row, int col, List<Coordinate> path) {
+        if (!maze.isValidLocation(row, col) || maze.isWall(row, col) || maze.isExplored(row, col)) {
+            return false;
+        }
+
+        path.add(new Coordinate(row, col));
+        maze.setVisited(row, col, true);
+
+        if (maze.isExit(row, col)) {
+            return true;
+        }
+
+        for (int[] direction : DIRECTIONS) {
+            Coordinate coordinate = getNextCoordinate(row, col, direction[0], direction[1]);
+            if (explore(maze, coordinate.getX(), coordinate.getY(), path)) {
+                return true;
+            }
+        }
+
+        path.remove(path.size() - 1);
+        return false;
+    }
+
+    private Coordinate getNextCoordinate(int row, int col, int i, int j) {
+        return new Coordinate(row + i, col + j);
+    }
+}
--- a/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/Maze.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/Maze.java
@ -0,0 +1,141 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Scanner;
+
+public class Maze {
+    private static final int ROAD = 0;
+    private static final int WALL = 1;
+    private static final int START = 2;
+    private static final int EXIT = 3;
+    private static final int PATH = 4;
+
+    private int[][] maze;
+    private boolean[][] visited;
+    private Coordinate start;
+    private Coordinate end;
+
+    public Maze(File maze) throws FileNotFoundException {
+        String fileText = "";
+        try (Scanner input = new Scanner(maze)) {
+            while (input.hasNextLine()) {
+                fileText += input.nextLine() + "\n";
+            }
+        }
+        initializeMaze(fileText);
+    }
+
+    private void initializeMaze(String text) {
+        if (text == null || (text = text.trim()).length() == 0) {
+            throw new IllegalArgumentException("empty lines data");
+        }
+
+        String[] lines = text.split("[\r]?\n");
+        maze = new int[lines.length][lines[0].length()];
+        visited = new boolean[lines.length][lines[0].length()];
+
+        for (int row = 0; row < getHeight(); row++) {
+            if (lines[row].length() != getWidth()) {
+                throw new IllegalArgumentException("line " + (row + 1) + " wrong length (was " + lines[row].length() + " but should be " + getWidth() + ")");
+            }
+
+            for (int col = 0; col < getWidth(); col++) {
+                if (lines[row].charAt(col) == '#')
+                    maze[row][col] = WALL;
+                else if (lines[row].charAt(col) == 'S') {
+                    maze[row][col] = START;
+                    start = new Coordinate(row, col);
+                } else if (lines[row].charAt(col) == 'E') {
+                    maze[row][col] = EXIT;
+                    end = new Coordinate(row, col);
+                } else
+                    maze[row][col] = ROAD;
+            }
+        }
+    }
+
+    public int getHeight() {
+        return maze.length;
+    }
+
+    public int getWidth() {
+        return maze[0].length;
+    }
+
+    public Coordinate getEntry() {
+        return start;
+    }
+
+    public Coordinate getExit() {
+        return end;
+    }
+
+    public boolean isExit(int x, int y) {
+        return x == end.getX() && y == end.getY();
+    }
+
+    public boolean isStart(int x, int y) {
+        return x == start.getX() && y == start.getY();
+    }
+
+    public boolean isExplored(int row, int col) {
+        return visited[row][col];
+    }
+
+    public boolean isWall(int row, int col) {
+        return maze[row][col] == WALL;
+    }
+
+    public void setVisited(int row, int col, boolean value) {
+        visited[row][col] = value;
+    }
+
+    public boolean isValidLocation(int row, int col) {
+        if (row < 0 || row >= getHeight() || col < 0 || col >= getWidth()) {
+            return false;
+        }
+        return true;
+    }
+
+    public void printPath(List<Coordinate> path) {
+        int[][] tempMaze = Arrays.stream(maze)
+            .map(int[]::clone)
+            .toArray(int[][]::new);
+        for (Coordinate coordinate : path) {
+            if (isStart(coordinate.getX(), coordinate.getY()) || isExit(coordinate.getX(), coordinate.getY())) {
+                continue;
+            }
+            tempMaze[coordinate.getX()][coordinate.getY()] = PATH;
+        }
+        System.out.println(toString(tempMaze));
+    }
+
+    public String toString(int[][] maze) {
+        StringBuilder result = new StringBuilder(getWidth() * (getHeight() + 1));
+        for (int row = 0; row < getHeight(); row++) {
+            for (int col = 0; col < getWidth(); col++) {
+                if (maze[row][col] == ROAD) {
+                    result.append(' ');
+                } else if (maze[row][col] == WALL) {
+                    result.append('#');
+                } else if (maze[row][col] == START) {
+                    result.append('S');
+                } else if (maze[row][col] == EXIT) {
+                    result.append('E');
+                } else {
+                    result.append('.');
+                }
+            }
+            result.append('\n');
+        }
+        return result.toString();
+    }
+
+    public void reset() {
+        for (int i = 0; i < visited.length; i++)
+            Arrays.fill(visited[i], false);
+    }
+}
--- a/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/MazeDriver.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/maze/solver/MazeDriver.java
@ -0,0 +1,34 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.io.File;
+import java.util.List;
+
+public class MazeDriver {
+    public static void main(String[] args) throws Exception {
+        File maze1 = new File("src/main/resources/maze/maze1.txt");
+        File maze2 = new File("src/main/resources/maze/maze2.txt");
+
+        execute(maze1);
+        execute(maze2);
+    }
+
+    private static void execute(File file) throws Exception {
+        Maze maze = new Maze(file);
+        dfs(maze);
+        bfs(maze);
+    }
+
+    private static void bfs(Maze maze) {
+        BFSMazeSolver bfs = new BFSMazeSolver();
+        List<Coordinate> path = bfs.solve(maze);
+        maze.printPath(path);
+        maze.reset();
+    }
+
+    private static void dfs(Maze maze) {
+        DFSMazeSolver dfs = new DFSMazeSolver();
+        List<Coordinate> path = dfs.solve(maze);
+        maze.printPath(path);
+        maze.reset();
+    }
+}
--- a/algorithms/src/main/java/com/baeldung/algorithms/sudoku/BacktrackingAlgorithm.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/sudoku/BacktrackingAlgorithm.java
@ -0,0 +1,104 @@
+package com.baeldung.algorithms.sudoku;
+
+import java.util.stream.IntStream;
+
+public class BacktrackingAlgorithm {
+
+    private static final int BOARD_SIZE = 9;
+    private static final int SUBSECTION_SIZE = 3;
+    private static final int BOARD_START_INDEX = 0;
+
+    private static final int NO_VALUE = 0;
+    private static final int MIN_VALUE = 1;
+    private static final int MAX_VALUE = 9;
+
+    private static int[][] board = {
+      {8, 0, 0, 0, 0, 0, 0, 0, 0},
+      {0, 0, 3, 6, 0, 0, 0, 0, 0},
+      {0, 7, 0, 0, 9, 0, 2, 0, 0},
+      {0, 5, 0, 0, 0, 7, 0, 0, 0},
+      {0, 0, 0, 0, 4, 5, 7, 0, 0},
+      {0, 0, 0, 1, 0, 0, 0, 3, 0},
+      {0, 0, 1, 0, 0, 0, 0, 6, 8},
+      {0, 0, 8, 5, 0, 0, 0, 1, 0},
+      {0, 9, 0, 0, 0, 0, 4, 0, 0}
+    };
+
+    public static void main(String[] args) {
+        BacktrackingAlgorithm solver = new BacktrackingAlgorithm();
+        solver.solve(board);
+        solver.printBoard();
+    }
+
+    private void printBoard() {
+        for (int row = BOARD_START_INDEX; row < BOARD_SIZE; row++) {
+            for (int column = BOARD_START_INDEX; column < BOARD_SIZE; column++) {
+                System.out.print(board[row][column] + " ");
+            }
+            System.out.println();
+        }
+    }
+
+    private boolean solve(int[][] board) {
+        for (int r = BOARD_START_INDEX; r < BOARD_SIZE; r++) {
+            for (int c = BOARD_START_INDEX; c < BOARD_SIZE; c++) {
+                if (board[r][c] == NO_VALUE) {
+                    for (int k = MIN_VALUE; k <= MAX_VALUE; k++) {
+                        board[r][c] = k;
+                        if (isValid(board, r, c) && solve(board)) {
+                            return true;
+                        }
+                        board[r][c] = NO_VALUE;
+                    }
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    private boolean isValid(int[][] board, int r, int c) {
+        return rowConstraint(board, r) &&
+          columnConstraint(board, c) &&
+          subsectionConstraint(board, r, c);
+    }
+
+    private boolean subsectionConstraint(int[][] board, int r, int c) {
+        boolean[] constraint = new boolean[BOARD_SIZE];
+        int subsectionRowStart = (r / SUBSECTION_SIZE) * SUBSECTION_SIZE;
+        int subsectionRowEnd = subsectionRowStart + SUBSECTION_SIZE;
+
+        int subsectionColumnStart = (c / SUBSECTION_SIZE) * SUBSECTION_SIZE;
+        int subsectionColumnEnd = subsectionColumnStart + SUBSECTION_SIZE;
+
+        for (int i = subsectionRowStart; i < subsectionRowEnd; i++) {
+            for (int j = subsectionColumnStart; j < subsectionColumnEnd; j++) {
+                if (!checkConstraint(board, i, constraint, j)) return false;
+            }
+        }
+        return true;
+    }
+
+    private boolean columnConstraint(int[][] board, int c) {
+        boolean[] constraint = new boolean[BOARD_SIZE];
+        return IntStream.range(BOARD_START_INDEX, BOARD_SIZE)
+          .allMatch(i -> checkConstraint(board, i, constraint, c));
+    }
+
+    private boolean rowConstraint(int[][] board, int r) {
+        boolean[] constraint = new boolean[BOARD_SIZE];
+        return IntStream.range(BOARD_START_INDEX, BOARD_SIZE)
+          .allMatch(i -> checkConstraint(board, r, constraint, i));
+    }
+
+    private boolean checkConstraint(int[][] board, int r, boolean[] constraint, int c) {
+        if (board[r][c] != NO_VALUE) {
+            if (!constraint[board[r][c] - 1]) {
+                constraint[board[r][c] - 1] = true;
+            } else {
+                return false;
+            }
+        }
+        return true;
+    }
+}
--- a/algorithms/src/main/java/com/baeldung/algorithms/sudoku/ColumnNode.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/sudoku/ColumnNode.java
@ -0,0 +1,33 @@
+package com.baeldung.algorithms.sudoku;
+
+class ColumnNode extends DancingNode {
+    int size;
+    String name;
+
+    ColumnNode(String n) {
+        super();
+        size = 0;
+        name = n;
+        C = this;
+    }
+
+    void cover() {
+        unlinkLR();
+        for (DancingNode i = this.D; i != this; i = i.D) {
+            for (DancingNode j = i.R; j != i; j = j.R) {
+                j.unlinkUD();
+                j.C.size--;
+            }
+        }
+    }
+
+    void uncover() {
+        for (DancingNode i = this.U; i != this; i = i.U) {
+            for (DancingNode j = i.L; j != i; j = j.L) {
+                j.C.size++;
+                j.relinkUD();
+            }
+        }
+        relinkLR();
+    }
+}
--- a/algorithms/src/main/java/com/baeldung/algorithms/sudoku/DancingLinks.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/sudoku/DancingLinks.java
@ -0,0 +1,133 @@
+package com.baeldung.algorithms.sudoku;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+
+public class DancingLinks {
+
+    private ColumnNode header;
+    private List<DancingNode> answer;
+
+    private void search(int k) {
+        if (header.R == header) {
+            handleSolution(answer);
+        } else {
+            ColumnNode c = selectColumnNodeHeuristic();
+            c.cover();
+
+            for (DancingNode r = c.D; r != c; r = r.D) {
+                answer.add(r);
+
+                for (DancingNode j = r.R; j != r; j = j.R) {
+                    j.C.cover();
+                }
+
+                search(k + 1);
+
+                r = answer.remove(answer.size() - 1);
+                c = r.C;
+
+                for (DancingNode j = r.L; j != r; j = j.L) {
+                    j.C.uncover();
+                }
+            }
+            c.uncover();
+        }
+    }
+
+    private ColumnNode selectColumnNodeHeuristic() {
+        int min = Integer.MAX_VALUE;
+        ColumnNode ret = null;
+        for (ColumnNode c = (ColumnNode) header.R; c != header; c = (ColumnNode) c.R) {
+            if (c.size < min) {
+                min = c.size;
+                ret = c;
+            }
+        }
+        return ret;
+    }
+
+    private ColumnNode makeDLXBoard(boolean[][] grid) {
+        final int COLS = grid[0].length;
+
+        ColumnNode headerNode = new ColumnNode("header");
+        List<ColumnNode> columnNodes = new ArrayList<>();
+
+        for (int i = 0; i < COLS; i++) {
+            ColumnNode n = new ColumnNode(Integer.toString(i));
+            columnNodes.add(n);
+            headerNode = (ColumnNode) headerNode.hookRight(n);
+        }
+        headerNode = headerNode.R.C;
+
+        for (boolean[] aGrid : grid) {
+            DancingNode prev = null;
+            for (int j = 0; j < COLS; j++) {
+                if (aGrid[j]) {
+                    ColumnNode col = columnNodes.get(j);
+                    DancingNode newNode = new DancingNode(col);
+                    if (prev == null)
+                        prev = newNode;
+                    col.U.hookDown(newNode);
+                    prev = prev.hookRight(newNode);
+                    col.size++;
+                }
+            }
+        }
+
+        headerNode.size = COLS;
+
+        return headerNode;
+    }
+
+    DancingLinks(boolean[][] cover) {
+        header = makeDLXBoard(cover);
+    }
+
+    public void runSolver() {
+        answer = new LinkedList<>();
+        search(0);
+    }
+
+    private void handleSolution(List<DancingNode> answer) {
+        int[][] result = parseBoard(answer);
+        printSolution(result);
+    }
+
+    private int size = 9;
+
+    private int[][] parseBoard(List<DancingNode> answer) {
+        int[][] result = new int[size][size];
+        for (DancingNode n : answer) {
+            DancingNode rcNode = n;
+            int min = Integer.parseInt(rcNode.C.name);
+            for (DancingNode tmp = n.R; tmp != n; tmp = tmp.R) {
+                int val = Integer.parseInt(tmp.C.name);
+                if (val < min) {
+                    min = val;
+                    rcNode = tmp;
+                }
+            }
+            int ans1 = Integer.parseInt(rcNode.C.name);
+            int ans2 = Integer.parseInt(rcNode.R.C.name);
+            int r = ans1 / size;
+            int c = ans1 % size;
+            int num = (ans2 % size) + 1;
+            result[r][c] = num;
+        }
+        return result;
+    }
+
+    private static void printSolution(int[][] result) {
+        int size = result.length;
+        for (int[] aResult : result) {
+            StringBuilder ret = new StringBuilder();
+            for (int j = 0; j < size; j++) {
+                ret.append(aResult[j]).append(" ");
+            }
+            System.out.println(ret);
+        }
+        System.out.println();
+    }
+}
--- a/algorithms/src/main/java/com/baeldung/algorithms/sudoku/DancingLinksAlgorithm.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/sudoku/DancingLinksAlgorithm.java
@ -0,0 +1,121 @@
+package com.baeldung.algorithms.sudoku;
+
+import java.util.Arrays;
+
+public class DancingLinksAlgorithm {
+    private static final int BOARD_SIZE = 9;
+    private static final int SUBSECTION_SIZE = 3;
+    private static final int NO_VALUE = 0;
+    private static final int CONSTRAINTS = 4;
+    private static final int MIN_VALUE = 1;
+    private static final int MAX_VALUE = 9;
+    private static final int COVER_START_INDEX = 1;
+
+    private static int[][] board = {
+      {8, 0, 0, 0, 0, 0, 0, 0, 0},
+      {0, 0, 3, 6, 0, 0, 0, 0, 0},
+      {0, 7, 0, 0, 9, 0, 2, 0, 0},
+      {0, 5, 0, 0, 0, 7, 0, 0, 0},
+      {0, 0, 0, 0, 4, 5, 7, 0, 0},
+      {0, 0, 0, 1, 0, 0, 0, 3, 0},
+      {0, 0, 1, 0, 0, 0, 0, 6, 8},
+      {0, 0, 8, 5, 0, 0, 0, 1, 0},
+      {0, 9, 0, 0, 0, 0, 4, 0, 0}
+    };
+
+    public static void main(String[] args) {
+        DancingLinksAlgorithm solver = new DancingLinksAlgorithm();
+        solver.solve(board);
+    }
+
+    private void solve(int[][] board) {
+        boolean[][] cover = initializeExactCoverBoard(board);
+        DancingLinks dlx = new DancingLinks(cover);
+        dlx.runSolver();
+    }
+
+    private int getIndex(int row, int col, int num) {
+        return (row - 1) * BOARD_SIZE * BOARD_SIZE + (col - 1) * BOARD_SIZE + (num - 1);
+    }
+
+    private boolean[][] createExactCoverBoard() {
+        boolean[][] coverBoard = new boolean[BOARD_SIZE * BOARD_SIZE * MAX_VALUE][BOARD_SIZE * BOARD_SIZE * CONSTRAINTS];
+
+        int hBase = 0;
+        hBase = checkCellConstraint(coverBoard, hBase);
+        hBase = checkRowConstraint(coverBoard, hBase);
+        hBase = checkColumnConstraint(coverBoard, hBase);
+        checkSubsectionConstraint(coverBoard, hBase);
+        
+        return coverBoard;
+    }
+
+    private int checkSubsectionConstraint(boolean[][] coverBoard, int hBase) {
+        for (int br = COVER_START_INDEX; br <= BOARD_SIZE; br += SUBSECTION_SIZE) {
+            for (int bc = COVER_START_INDEX; bc <= BOARD_SIZE; bc += SUBSECTION_SIZE) {
+                for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
+                    for (int rDelta = 0; rDelta < SUBSECTION_SIZE; rDelta++) {
+                        for (int cDelta = 0; cDelta < SUBSECTION_SIZE; cDelta++) {
+                            int index = getIndex(br + rDelta, bc + cDelta, n);
+                            coverBoard[index][hBase] = true;
+                        }
+                    }
+                }
+            }
+        }
+        return hBase;
+    }
+
+    private int checkColumnConstraint(boolean[][] coverBoard, int hBase) {
+        for (int c = COVER_START_INDEX; c <= BOARD_SIZE; c++) {
+            for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
+                for (int r1 = COVER_START_INDEX; r1 <= BOARD_SIZE; r1++) {
+                    int index = getIndex(r1, c, n);
+                    coverBoard[index][hBase] = true;
+                }
+            }
+        }
+        return hBase;
+    }
+
+    private int checkRowConstraint(boolean[][] coverBoard, int hBase) {
+        for (int r = COVER_START_INDEX; r <= BOARD_SIZE; r++) {
+            for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
+                for (int c1 = COVER_START_INDEX; c1 <= BOARD_SIZE; c1++) {
+                    int index = getIndex(r, c1, n);
+                    coverBoard[index][hBase] = true;
+                }
+            }
+        }
+        return hBase;
+    }
+
+    private int checkCellConstraint(boolean[][] coverBoard, int hBase) {
+        for (int r = COVER_START_INDEX; r <= BOARD_SIZE; r++) {
+            for (int c = COVER_START_INDEX; c <= BOARD_SIZE; c++, hBase++) {
+                for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++) {
+                    int index = getIndex(r, c, n);
+                    coverBoard[index][hBase] = true;
+                }
+            }
+        }
+        return hBase;
+    }
+
+    private boolean[][] initializeExactCoverBoard(int[][] board) {
+        boolean[][] coverBoard = createExactCoverBoard();
+        for (int i = COVER_START_INDEX; i <= BOARD_SIZE; i++) {
+            for (int j = COVER_START_INDEX; j <= BOARD_SIZE; j++) {
+                int n = board[i - 1][j - 1];
+                if (n != NO_VALUE) {
+                    for (int num = MIN_VALUE; num <= MAX_VALUE; num++) {
+                        if (num != n) {
+                            Arrays.fill(coverBoard[getIndex(i, j, num)], false);
+                        }
+                    }
+                }
+            }
+        }
+        return coverBoard;
+    }
+}
--- a/algorithms/src/main/java/com/baeldung/algorithms/sudoku/DancingNode.java
+++ b/algorithms/src/main/java/com/baeldung/algorithms/sudoku/DancingNode.java
@ -0,0 +1,50 @@
+package com.baeldung.algorithms.sudoku;
+
+class DancingNode {
+    DancingNode L, R, U, D;
+    ColumnNode C;
+
+    DancingNode hookDown(DancingNode n1) {
+        assert (this.C == n1.C);
+        n1.D = this.D;
+        n1.D.U = n1;
+        n1.U = this;
+        this.D = n1;
+        return n1;
+    }
+
+    DancingNode hookRight(DancingNode n1) {
+        n1.R = this.R;
+        n1.R.L = n1;
+        n1.L = this;
+        this.R = n1;
+        return n1;
+    }
+
+    void unlinkLR() {
+        this.L.R = this.R;
+        this.R.L = this.L;
+    }
+
+    void relinkLR() {
+        this.L.R = this.R.L = this;
+    }
+
+    void unlinkUD() {
+        this.U.D = this.D;
+        this.D.U = this.U;
+    }
+
+    void relinkUD() {
+        this.U.D = this.D.U = this;
+    }
+
+    DancingNode() {
+        L = R = U = D = this;
+    }
+
+    DancingNode(ColumnNode c) {
+        this();
+        C = c;
+    }
+}
--- a/algorithms/src/main/resources/maze/maze1.txt
+++ b/algorithms/src/main/resources/maze/maze1.txt
@ -0,0 +1,12 @@
+S ########
+#        #
+# ### ## #
+# #    # #
+# #  # # #
+# ## #####
+# #      #
+# # #  # #
+##### ####
+#   #    E
+# #    # #
+##########
--- a/algorithms/src/main/resources/maze/maze2.txt
+++ b/algorithms/src/main/resources/maze/maze2.txt
@ -0,0 +1,22 @@
+S ##########################
+# #      #                 #
+# # ####   ############### #
+# # #    # #               #
+# # #### # # ###############
+# # #    # # #             #
+# # # #### ### ########### #
+# # # #        #           #
+#       ################## #
+#########    # # #       # #
+# #       #### # ####### # #
+# # ### ###  # # #       # #
+#   #       ##   # ##### # #
+##### #######  # #     # # #
+#     #       ## ## #### # #
+# ##### #######     #      #
+#       #       ############
+####### #########        # #
+#       #         ######## #
+# ####### ###### ##   #    E
+#         #         #   ## #
+############################
--- a/core-java-9/src/test/java/com/baeldung/java9/httpclient/HttpClientTest.java
+++ b/core-java-9/src/test/java/com/baeldung/java9/httpclient/HttpClientTest.java
@ -0,0 +1,218 @@
+package com.baeldung.java9.httpclient;
+
+import jdk.incubator.http.HttpClient;
+import jdk.incubator.http.HttpRequest;
+import jdk.incubator.http.HttpResponse;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.*;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.stream.Collectors;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.collection.IsEmptyCollection.empty;
+import static org.hamcrest.core.IsNot.not;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Created by adam.
+ */
+public class HttpClientTest {
+
+    @Test
+    public void shouldReturnSampleDataContentWhenConnectViaSystemProxy() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyProcessor.fromString("Sample body"))
+            .build();
+
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .proxy(ProxySelector.getDefault())
+            .build()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample body"));
+    }
+
+    @Test
+    public void shouldNotFollowRedirectWhenSetToDefaultNever() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("http://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_1_1)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .build()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_MOVED_PERM));
+        assertThat(response.body(), containsString("https://stackoverflow.com/"));
+    }
+
+    @Test
+    public void shouldFollowRedirectWhenSetToAlways() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("http://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_1_1)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .followRedirects(HttpClient.Redirect.ALWAYS)
+            .build()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.finalRequest()
+            .uri()
+            .toString(), equalTo("https://stackoverflow.com/"));
+    }
+
+    @Test
+    public void shouldReturnOKStatusForAuthenticatedAccess() throws URISyntaxException, IOException, InterruptedException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/basic-auth"))
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .authenticator(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication("postman", "password".toCharArray());
+                }
+            })
+            .build()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldSendRequestAsync() throws URISyntaxException, InterruptedException, ExecutionException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyProcessor.fromString("Sample body"))
+            .build();
+        CompletableFuture<HttpResponse<String>> response = HttpClient.newBuilder()
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldUseJustTwoThreadWhenProcessingSendAsyncRequest() throws URISyntaxException, InterruptedException, ExecutionException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        ExecutorService executorService = Executors.newFixedThreadPool(2);
+
+        CompletableFuture<HttpResponse<String>> response1 = HttpClient.newBuilder()
+            .executor(executorService)
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandler.asString());
+
+        CompletableFuture<HttpResponse<String>> response2 = HttpClient.newBuilder()
+            .executor(executorService)
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandler.asString());
+
+        CompletableFuture<HttpResponse<String>> response3 = HttpClient.newBuilder()
+            .executor(executorService)
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandler.asString());
+
+        CompletableFuture.allOf(response1, response2, response3)
+            .join();
+
+        assertThat(response1.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response2.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response3.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldNotStoreCookieWhenPolicyAcceptNone() throws URISyntaxException, IOException, InterruptedException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        HttpClient httpClient = HttpClient.newBuilder()
+            .cookieManager(new CookieManager(null, CookiePolicy.ACCEPT_NONE))
+            .build();
+
+        httpClient.send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(httpClient.cookieManager()
+            .get()
+            .getCookieStore()
+            .getCookies(), empty());
+    }
+
+    @Test
+    public void shouldStoreCookieWhenPolicyAcceptAll() throws URISyntaxException, IOException, InterruptedException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        HttpClient httpClient = HttpClient.newBuilder()
+            .cookieManager(new CookieManager(null, CookiePolicy.ACCEPT_ALL))
+            .build();
+
+        httpClient.send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(httpClient.cookieManager()
+            .get()
+            .getCookieStore()
+            .getCookies(), not(empty()));
+    }
+
+    @Test
+    public void shouldProcessMultipleRequestViaStream() throws URISyntaxException, ExecutionException, InterruptedException {
+        List<URI> targets = Arrays.asList(new URI("https://postman-echo.com/get?foo1=bar1"), new URI("https://postman-echo.com/get?foo2=bar2"));
+
+        HttpClient client = HttpClient.newHttpClient();
+
+        List<CompletableFuture<String>> futures = targets.stream()
+            .map(target -> client.sendAsync(HttpRequest.newBuilder(target)
+                .GET()
+                .build(), HttpResponse.BodyHandler.asString())
+                .thenApply(response -> response.body()))
+            .collect(Collectors.toList());
+
+        CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
+            .join();
+
+        if (futures.get(0)
+            .get()
+            .contains("foo1")) {
+            assertThat(futures.get(0)
+                .get(), containsString("bar1"));
+            assertThat(futures.get(1)
+                .get(), containsString("bar2"));
+        } else {
+            assertThat(futures.get(1)
+                .get(), containsString("bar2"));
+            assertThat(futures.get(1)
+                .get(), containsString("bar1"));
+        }
+
+    }
+
+}
--- a/core-java-9/src/test/java/com/baeldung/java9/httpclient/HttpRequestTest.java
+++ b/core-java-9/src/test/java/com/baeldung/java9/httpclient/HttpRequestTest.java
@ -0,0 +1,171 @@
+package com.baeldung.java9.httpclient;
+
+import jdk.incubator.http.HttpClient;
+import jdk.incubator.http.HttpRequest;
+import jdk.incubator.http.HttpResponse;
+import org.junit.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.nio.file.Paths;
+import java.security.NoSuchAlgorithmException;
+import java.time.Duration;
+
+import static java.time.temporal.ChronoUnit.SECONDS;
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Created by adam.
+ */
+public class HttpRequestTest {
+
+    @Test
+    public void shouldReturnStatusOKWhenSendGetRequest() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldUseHttp2WhenWebsiteUsesHttp2() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_2)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.version(), equalTo(HttpClient.Version.HTTP_2));
+    }
+
+    @Test
+    public void shouldFallbackToHttp1_1WhenWebsiteDoesNotUseHttp2() throws IOException, InterruptedException, URISyntaxException, NoSuchAlgorithmException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .version(HttpClient.Version.HTTP_2)
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.version(), equalTo(HttpClient.Version.HTTP_1_1));
+    }
+
+    @Test
+    public void shouldReturnStatusOKWhenSendGetRequestWithDummyHeaders() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .headers("key1", "value1", "key2", "value2")
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldReturnStatusOKWhenSendGetRequestTimeoutSet() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .timeout(Duration.of(10, SECONDS))
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldReturnNoContentWhenPostWithNoBody() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .POST(HttpRequest.noBody())
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldReturnSampleDataContentWhenPostWithBodyText() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyProcessor.fromString("Sample request body"))
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample request body"));
+    }
+
+    @Test
+    public void shouldReturnSampleDataContentWhenPostWithInputStream() throws IOException, InterruptedException, URISyntaxException {
+        byte[] sampleData = "Sample request body".getBytes();
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyProcessor.fromInputStream(() -> new ByteArrayInputStream(sampleData)))
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample request body"));
+    }
+
+    @Test
+    public void shouldReturnSampleDataContentWhenPostWithByteArrayProcessorStream() throws IOException, InterruptedException, URISyntaxException {
+        byte[] sampleData = "Sample request body".getBytes();
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyProcessor.fromByteArray(sampleData))
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample request body"));
+    }
+
+    @Test
+    public void shouldReturnSampleDataContentWhenPostWithFileProcessorStream() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyProcessor.fromFile(Paths.get("src/test/resources/sample.txt")))
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample file content"));
+    }
+
+}
--- a/core-java-9/src/test/java/com/baeldung/java9/httpclient/HttpResponseTest.java
+++ b/core-java-9/src/test/java/com/baeldung/java9/httpclient/HttpResponseTest.java
@ -0,0 +1,55 @@
+package com.baeldung.java9.httpclient;
+
+import jdk.incubator.http.HttpClient;
+import jdk.incubator.http.HttpRequest;
+import jdk.incubator.http.HttpResponse;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.Matchers.isEmptyString;
+import static org.hamcrest.core.IsNot.not;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Created by adam.
+ */
+public class HttpResponseTest {
+
+    @Test
+    public void shouldReturnStatusOKWhenSendGetRequest() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), not(isEmptyString()));
+    }
+
+    @Test
+    public void shouldResponseURIDifferentThanRequestUIRWhenRedirect() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("http://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_1_1)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .followRedirects(HttpClient.Redirect.ALWAYS)
+            .build()
+            .send(request, HttpResponse.BodyHandler.asString());
+
+        assertThat(request.uri()
+            .toString(), equalTo("http://stackoverflow.com"));
+        assertThat(response.uri()
+            .toString(), equalTo("https://stackoverflow.com/"));
+    }
+
+}
--- a/core-java-concurrency/src/main/java/com/baeldung/concurrent/prioritytaskexecution/Job.java
+++ b/core-java-concurrency/src/main/java/com/baeldung/concurrent/prioritytaskexecution/Job.java
@ -0,0 +1,24 @@
+package com.baeldung.concurrent.prioritytaskexecution;
+
+public class Job implements Runnable {
+    private String jobName;
+    private JobPriority jobPriority;
+    
+    public Job(String jobName, JobPriority jobPriority) {
+        this.jobName = jobName;
+        this.jobPriority = jobPriority != null ? jobPriority : JobPriority.MEDIUM;
+    }
+
+    public JobPriority getJobPriority() {
+        return jobPriority;
+    }
+
+    @Override
+    public void run() {
+        try {
+            System.out.println("Job:" + jobName + " Priority:" + jobPriority);
+            Thread.sleep(1000);
+        } catch (InterruptedException ignored) {
+        }
+    }
+}
--- a/core-java-concurrency/src/main/java/com/baeldung/concurrent/prioritytaskexecution/JobPriority.java
+++ b/core-java-concurrency/src/main/java/com/baeldung/concurrent/prioritytaskexecution/JobPriority.java
@ -0,0 +1,7 @@
+package com.baeldung.concurrent.prioritytaskexecution;
+
+public enum JobPriority {
+    HIGH,
+    MEDIUM,
+    LOW
+}
--- a/core-java-concurrency/src/main/java/com/baeldung/concurrent/prioritytaskexecution/PriorityJobScheduler.java
+++ b/core-java-concurrency/src/main/java/com/baeldung/concurrent/prioritytaskexecution/PriorityJobScheduler.java
@ -0,0 +1,56 @@
+package com.baeldung.concurrent.prioritytaskexecution;
+
+import java.util.Comparator;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.PriorityBlockingQueue;
+import java.util.concurrent.TimeUnit;
+
+public class PriorityJobScheduler {
+
+    private ExecutorService priorityJobPoolExecutor;
+    private ExecutorService priorityJobScheduler;
+    private PriorityBlockingQueue<Runnable> priorityQueue;
+
+    public PriorityJobScheduler(Integer poolSize, Integer queueSize) {
+        priorityJobPoolExecutor = Executors.newFixedThreadPool(poolSize);
+        Comparator<? super Job> jobComparator = Comparator.comparing(Job::getJobPriority);
+        priorityQueue = new PriorityBlockingQueue<Runnable>(queueSize, 
+          (Comparator<? super Runnable>) jobComparator);
+
+        priorityJobScheduler = Executors.newSingleThreadExecutor();
+        priorityJobScheduler.execute(()->{
+            while (true) {
+                try {
+                    priorityJobPoolExecutor.execute(priorityQueue.take());
+                } catch (InterruptedException e) {
+                    break;
+                }
+            }
+        });
+    }
+
+    public void scheduleJob(Job job) {
+        priorityQueue.add(job);
+    }
+
+    public int getQueuedTaskCount() {
+        return priorityQueue.size();
+    }
+
+    protected void close(ExecutorService scheduler) {
+        scheduler.shutdown();
+        try {
+            if (!scheduler.awaitTermination(5, TimeUnit.SECONDS)) {
+                scheduler.shutdownNow();
+            }
+        } catch (InterruptedException e) {
+            scheduler.shutdownNow();
+        }
+    }
+
+    public void closeScheduler() {
+        close(priorityJobPoolExecutor);
+        close(priorityJobScheduler);
+    }
+}
--- a/core-java-concurrency/src/main/java/com/baeldung/concurrent/waitandnotify/Data.java
+++ b/core-java-concurrency/src/main/java/com/baeldung/concurrent/waitandnotify/Data.java
@ -1,7 +1,5 @@
 package com.baeldung.concurrent.waitandnotify;

-import org.slf4j.Logger;
-
 public class Data {
    private String packet;
    
@ -14,6 +12,7 @@ public class Data {
            try {
                wait();
            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt(); 
                System.out.println("Thread Interrupted");
            }
        }
@ -28,6 +27,7 @@ public class Data {
            try { 
                wait();
            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt(); 
                System.out.println("Thread Interrupted");
            }
        }
--- a/core-java-concurrency/src/main/java/com/baeldung/concurrent/waitandnotify/Receiver.java
+++ b/core-java-concurrency/src/main/java/com/baeldung/concurrent/waitandnotify/Receiver.java
@ -20,6 +20,7 @@ public class Receiver implements Runnable {
            try {
                Thread.sleep(ThreadLocalRandom.current().nextInt(1000, 5000));
            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt(); 
                System.out.println("Thread Interrupted");
            }
        }
--- a/core-java-concurrency/src/main/java/com/baeldung/concurrent/waitandnotify/Sender.java
+++ b/core-java-concurrency/src/main/java/com/baeldung/concurrent/waitandnotify/Sender.java
@ -25,6 +25,7 @@ public class Sender implements Runnable {
            try {
                Thread.sleep(ThreadLocalRandom.current().nextInt(1000, 5000));
            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt(); 
                System.out.println("Thread Interrupted");
            }
        }
--- a/core-java-concurrency/src/test/java/com/baeldung/concurrent/prioritytaskexecution/PriorityJobSchedulerUnitTest.java
+++ b/core-java-concurrency/src/test/java/com/baeldung/concurrent/prioritytaskexecution/PriorityJobSchedulerUnitTest.java
@ -0,0 +1,38 @@
+package com.baeldung.concurrent.prioritytaskexecution;
+
+import org.junit.Test;
+
+public class PriorityJobSchedulerUnitTest {
+    private static int POOL_SIZE = 1;
+    private static int QUEUE_SIZE = 10;
+    
+    @Test
+    public void whenMultiplePriorityJobsQueued_thenHighestPriorityJobIsPicked() {
+        Job job1 = new Job("Job1", JobPriority.LOW);
+        Job job2 = new Job("Job2", JobPriority.MEDIUM);
+        Job job3 = new Job("Job3", JobPriority.HIGH);
+        Job job4 = new Job("Job4", JobPriority.MEDIUM);
+        Job job5 = new Job("Job5", JobPriority.LOW);
+        Job job6 = new Job("Job6", JobPriority.HIGH);
+        
+        PriorityJobScheduler pjs = new PriorityJobScheduler(POOL_SIZE, QUEUE_SIZE);
+        
+        pjs.scheduleJob(job1);
+        pjs.scheduleJob(job2);
+        pjs.scheduleJob(job3);
+        pjs.scheduleJob(job4);
+        pjs.scheduleJob(job5);
+        pjs.scheduleJob(job6);
+        
+        // ensure no tasks is pending before closing the scheduler
+        while (pjs.getQueuedTaskCount() != 0);
+        
+        // delay to avoid job sleep (added for demo) being interrupted
+        try {
+            Thread.sleep(2000);
+        } catch (InterruptedException ignored) {
+        }
+        
+        pjs.closeScheduler();
+    }
+}
--- a/core-java-concurrency/src/test/java/com/baeldung/concurrent/waitandnotify/NetworkIntegrationTest.java
+++ b/core-java-concurrency/src/test/java/com/baeldung/concurrent/waitandnotify/NetworkIntegrationTest.java
@ -57,7 +57,8 @@ public class NetworkIntegrationTest {
            sender.join();
            receiver.join();
        } catch (InterruptedException e) {
-            e.printStackTrace();
+            Thread.currentThread().interrupt(); 
+            System.out.println("Thread Interrupted");
        }
        
        assertEquals(expected, outContent.toString());
--- a/core-java/src/main/java/com/baeldung/designpatterns/observer/Channel.java
+++ b/core-java/src/main/java/com/baeldung/designpatterns/observer/Channel.java
@ -0,0 +1,5 @@
+package com.baeldung.designpatterns.observer;
+
+public interface Channel {
+    public void update(Object o);
+}
--- a/core-java/src/main/java/com/baeldung/designpatterns/observer/NewsAgency.java
+++ b/core-java/src/main/java/com/baeldung/designpatterns/observer/NewsAgency.java
@ -0,0 +1,24 @@
+package com.baeldung.designpatterns.observer;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class NewsAgency {
+    private String news;
+    private List<Channel> channels = new ArrayList<>();
+
+    public void addObserver(Channel channel) {
+        this.channels.add(channel);
+    }
+
+    public void removeObserver(Channel channel) {
+        this.channels.remove(channel);
+    }
+
+    public void setNews(String news) {
+        this.news = news;
+        for (Channel channel : this.channels) {
+            channel.update(this.news);
+        }
+    }
+}
--- a/core-java/src/main/java/com/baeldung/designpatterns/observer/NewsChannel.java
+++ b/core-java/src/main/java/com/baeldung/designpatterns/observer/NewsChannel.java
@ -0,0 +1,20 @@
+package com.baeldung.designpatterns.observer;
+
+public class NewsChannel implements Channel {
+
+    private String news;
+
+    @Override
+    public void update(Object news) {
+        this.setNews((String) news);
+    }
+
+    public String getNews() {
+        return news;
+    }
+
+    public void setNews(String news) {
+        this.news = news;
+    }
+
+}
--- a/core-java/src/main/java/com/baeldung/designpatterns/observer/ONewsAgency.java
+++ b/core-java/src/main/java/com/baeldung/designpatterns/observer/ONewsAgency.java
@ -0,0 +1,13 @@
+package com.baeldung.designpatterns.observer;
+
+import java.util.Observable;
+
+public class ONewsAgency extends Observable {
+    private String news;
+
+    public void setNews(String news) {
+        this.news = news;
+        setChanged();
+        notifyObservers(news);
+    }
+}
--- a/core-java/src/main/java/com/baeldung/designpatterns/observer/ONewsChannel.java
+++ b/core-java/src/main/java/com/baeldung/designpatterns/observer/ONewsChannel.java
@ -0,0 +1,22 @@
+package com.baeldung.designpatterns.observer;
+
+import java.util.Observable;
+import java.util.Observer;
+
+public class ONewsChannel implements Observer {
+
+    private String news;
+
+    @Override
+    public void update(Observable o, Object news) {
+        this.setNews((String) news);
+    }
+
+    public String getNews() {
+        return news;
+    }
+
+    public void setNews(String news) {
+        this.news = news;
+    }
+}
--- a/core-java/src/main/java/com/baeldung/designpatterns/observer/PCLNewsAgency.java
+++ b/core-java/src/main/java/com/baeldung/designpatterns/observer/PCLNewsAgency.java
@ -0,0 +1,28 @@
+package com.baeldung.designpatterns.observer;
+
+import java.beans.PropertyChangeListener;
+import java.beans.PropertyChangeSupport;
+
+public class PCLNewsAgency {
+    private String news;
+
+    private PropertyChangeSupport support;
+
+    public PCLNewsAgency() {
+        support = new PropertyChangeSupport(this);
+    }
+
+    public void addPropertyChangeListener(PropertyChangeListener pcl) {
+        support.addPropertyChangeListener(pcl);
+    }
+
+    public void removePropertyChangeListener(PropertyChangeListener pcl) {
+        support.removePropertyChangeListener(pcl);
+    }
+
+    public void setNews(String value) {
+        support.firePropertyChange("news", this.news, value);
+        this.news = value;
+
+    }
+}
--- a/core-java/src/main/java/com/baeldung/designpatterns/observer/PCLNewsChannel.java
+++ b/core-java/src/main/java/com/baeldung/designpatterns/observer/PCLNewsChannel.java
@ -0,0 +1,21 @@
+package com.baeldung.designpatterns.observer;
+
+import java.beans.PropertyChangeEvent;
+import java.beans.PropertyChangeListener;
+
+public class PCLNewsChannel implements PropertyChangeListener {
+
+    private String news;
+
+    public void propertyChange(PropertyChangeEvent evt) {
+        this.setNews((String) evt.getNewValue());
+    }
+
+    public String getNews() {
+        return news;
+    }
+
+    public void setNews(String news) {
+        this.news = news;
+    }
+}
--- a/core-java/src/main/java/com/baeldung/javac/Data.java
+++ b/core-java/src/main/java/com/baeldung/javac/Data.java
@ -0,0 +1,16 @@
+package com.baeldung.javac;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Data {
+    List<String> textList = new ArrayList();
+
+    public void addText(String text) {
+        textList.add(text);
+    }
+
+    public List getTextList() {
+        return this.textList;
+    }
+}
--- a/core-java/src/main/java/com/baeldung/string/Palindrome.java
+++ b/core-java/src/main/java/com/baeldung/string/Palindrome.java
@ -0,0 +1,53 @@
+package com.baeldung.string;
+
+public class Palindrome {
+
+    public boolean isPalindrome(String text) {
+        text = text.replaceAll("\\s+", "")
+            .toLowerCase();
+        int length = text.length();
+        int forward = 0;
+        int backward = length - 1;
+        boolean palindrome = true;
+        while (backward > forward) {
+            char forwardChar = text.charAt(forward++);
+            char backwardChar = text.charAt(backward--);
+            if (forwardChar != backwardChar)
+                return false;
+        }
+        return palindrome;
+    }
+
+    public boolean isPalindromeReverseTheString(String text) {
+        String reverse = "";
+        text = text.replaceAll("\\s+", "").toLowerCase();
+        char[] plain = text.toCharArray();
+        for (int i = plain.length - 1; i >= 0; i--)
+            reverse += plain[i];
+        return reverse.equals(text);
+    }
+
+    public boolean isPalindromeUsingStringBuilder(String text) {
+        StringBuilder plain = new StringBuilder(text);
+        StringBuilder reverse = plain.reverse();
+        return reverse.equals(plain);
+    }
+
+    public boolean isPalindromeUsingStringBuffer(String text) {
+        StringBuffer plain = new StringBuffer(text);
+        StringBuffer reverse = plain.reverse();
+        return reverse.equals(plain);
+    }
+
+    public boolean isPalindromeRecursive(String text, int forward, int backward) {
+        if (forward == backward)
+            return true;
+        if ((text.charAt(forward)) != (text.charAt(backward)))
+            return false;
+        if (forward < backward + 1) {
+            return isPalindromeRecursive(text, forward + 1, backward - 1);
+        }
+
+        return true;
+    }
+}
--- a/core-java/src/main/java/javac-args/arguments
+++ b/core-java/src/main/java/javac-args/arguments
@ -0,0 +1,2 @@
+-d javac-target -verbose
+com/baeldung/javac/Data.java
--- a/core-java/src/main/java/javac-args/options
+++ b/core-java/src/main/java/javac-args/options
@ -0,0 +1,2 @@
+-d javac-target
+-verbose
--- a/core-java/src/main/java/javac-args/types
+++ b/core-java/src/main/java/javac-args/types
@ -0,0 +1 @@
+com/baeldung/javac/Data.java
--- a/core-java/src/main/java/javac-args/xlint-ops
+++ b/core-java/src/main/java/javac-args/xlint-ops
@ -0,0 +1,3 @@
+-d javac-target
+-Xlint:rawtypes,unchecked,static,cast,serial,fallthrough
+com/baeldung/javac/Data.java
--- a/core-java/src/test/java/com/baeldung/designpatterns/observer/ObserverIntegrationTest.java
+++ b/core-java/src/test/java/com/baeldung/designpatterns/observer/ObserverIntegrationTest.java
@ -0,0 +1,47 @@
+package com.baeldung.designpatterns.observer;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import com.baeldung.designpatterns.observer.NewsAgency;
+import com.baeldung.designpatterns.observer.NewsChannel;
+
+public class ObserverIntegrationTest {
+
+    @Test
+    public void whenChangingNewsAgencyState_thenNewsChannelNotified() {
+
+        NewsAgency observable = new NewsAgency();
+        NewsChannel observer = new NewsChannel();
+
+        observable.addObserver(observer);
+
+        observable.setNews("news");
+        assertEquals(observer.getNews(), "news");
+    }
+
+    @Test
+    public void whenChangingONewsAgencyState_thenONewsChannelNotified() {
+
+        ONewsAgency observable = new ONewsAgency();
+        ONewsChannel observer = new ONewsChannel();
+
+        observable.addObserver(observer);
+
+        observable.setNews("news");
+        assertEquals(observer.getNews(), "news");
+    }
+
+    @Test
+    public void whenChangingPCLNewsAgencyState_thenONewsChannelNotified() {
+
+        PCLNewsAgency observable = new PCLNewsAgency();
+        PCLNewsChannel observer = new PCLNewsChannel();
+
+        observable.addPropertyChangeListener(observer);
+
+        observable.setNews("news");
+        assertEquals(observer.getNews(), "news");
+    }
+}
--- a/core-java/src/test/java/com/baeldung/string/WhenCheckingPalindrome.java
+++ b/core-java/src/test/java/com/baeldung/string/WhenCheckingPalindrome.java
@ -0,0 +1,114 @@
+package com.baeldung.string;
+
+import java.util.Arrays;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class WhenCheckingPalindrome {
+
+    private String[] words = {
+            "Anna",
+            "Civic",
+            "Kayak",
+            "Level",
+            "Madam",
+    };
+
+    private String[] sentences = {
+            "Sore was I ere I saw Eros",
+            "Euston saw I was not Sue",
+            "Too hot to hoot",
+            "No mists or frost Simon",
+            "Stella won no wallets"
+    };
+    
+    private Palindrome palindrome = new Palindrome();
+    
+    @Test
+    public void whenWord_shouldBePalindrome() {
+        for(String word:words)
+            Assert.assertTrue(palindrome.isPalindrome(word));
+    }
+
+    @Test
+    public void whenSentence_shouldBePalindrome() {
+        for(String sentence:sentences)
+            Assert.assertTrue(palindrome.isPalindrome(sentence));
+    }
+    
+    @Test
+    public void whenReverseWord_shouldBePalindrome() {
+        for(String word:words)
+            Assert.assertTrue(palindrome.isPalindromeReverseTheString(word));
+    }
+    
+    @Test
+    public void whenReverseSentence_shouldBePalindrome() {
+        for(String sentence:sentences)
+            Assert.assertTrue(palindrome.isPalindromeReverseTheString(sentence));
+    }
+    
+    @Test
+    public void whenStringBuilderWord_shouldBePalindrome() {
+        for(String word:words)
+            Assert.assertTrue(palindrome.isPalindromeUsingStringBuilder(word));
+    }
+    
+    @Test
+    public void whenStringBuilderSentence_shouldBePalindrome() {
+        for(String sentence:sentences)
+            Assert.assertTrue(palindrome.isPalindromeUsingStringBuilder(sentence));
+    }
+    
+    @Test
+    public void whenStringBufferWord_shouldBePalindrome() {
+        for(String word:words)
+            Assert.assertTrue(palindrome.isPalindromeUsingStringBuffer(word));
+    }
+    
+    @Test
+    public void whenStringBufferSentence_shouldBePalindrome() {
+        for(String sentence:sentences)
+            
+            Assert.assertTrue(palindrome.isPalindromeUsingStringBuffer(sentence));
+    }
+    
+    @Test
+    public void whenPalindromeRecursive_wordShouldBePalindrome() {
+        for(String word:words) {
+            word = word.replaceAll("\\s+", "").toLowerCase();
+            int backward = word.length()-1;
+            
+            Assert.assertTrue(palindrome.isPalindromeRecursive(word,0,backward));
+        }
+    }
+    
+    @Test
+    public void whenPalindromeRecursive_sentenceShouldBePalindrome() {
+        for(String sentence:sentences) {
+            sentence = sentence.replaceAll("\\s+", "").toLowerCase();
+            int backward = sentence.length()-1;
+            
+            Assert.assertTrue(palindrome.isPalindromeRecursive(sentence,0,backward));
+        }
+    }
+    
+    @Test
+    public void whenPalindromeStreams_wordShouldBePalindrome() {
+        String[] expected = Arrays.stream(words)
+            .filter(palindrome::isPalindrome)
+            .toArray(String[]::new);
+        
+        Assert.assertArrayEquals(expected, words);
+    }
+    
+    @Test
+    public void whenPalindromeStreams_sentenceShouldBePalindrome() {
+        String[] expected = Arrays.stream(sentences)
+            .filter(palindrome::isPalindrome)
+            .toArray(String[]::new);
+        
+        Assert.assertArrayEquals(expected, sentences);
+    }
+}
--- a/core-kotlin/src/test/kotlin/com/baeldung/kotlin/InfixFunctionsTest.kt
+++ b/core-kotlin/src/test/kotlin/com/baeldung/kotlin/InfixFunctionsTest.kt
@ -0,0 +1,51 @@
+package com.baeldung.kotlin
+
+import org.junit.Assert
+import org.junit.Test
+
+class InfixFunctionsTest {
+    @Test
+    fun testColours() {
+        val color = 0x123456
+        val red = (color and 0xff0000) shr 16
+        val green = (color and 0x00ff00) shr 8
+        val blue = (color and 0x0000ff) shr 0
+
+        Assert.assertEquals(0x12, red)
+        Assert.assertEquals(0x34, green)
+        Assert.assertEquals(0x56, blue)
+    }
+
+    @Test
+    fun testNewAssertions() {
+        class Assertion<T>(private val target: T) {
+            infix fun isEqualTo(other: T) {
+                Assert.assertEquals(other, target)
+            }
+
+            infix fun isDifferentFrom(other: T) {
+                Assert.assertNotEquals(other, target)
+            }
+        }
+
+        val result = Assertion(5)
+
+        result isEqualTo 5
+
+        // The following two lines are expected to fail
+        // result isEqualTo 6
+        // result isDifferentFrom 5
+    }
+
+    @Test
+    fun testNewStringMethod() {
+        infix fun String.substringMatches(r: Regex) : List<String> {
+            return r.findAll(this)
+                    .map { it.value }
+                    .toList()
+        }
+
+        val matches = "a bc def" substringMatches ".*? ".toRegex()
+        Assert.assertEquals(listOf("a ", "bc "), matches)
+    }
+}
--- a/core-kotlin/src/test/kotlin/com/baeldung/kotlin/stdlib/RegexTest.kt
+++ b/core-kotlin/src/test/kotlin/com/baeldung/kotlin/stdlib/RegexTest.kt
@ -0,0 +1,128 @@
+package com.baeldung.kotlin.stdlib
+
+import org.junit.Test
+import java.beans.ExceptionListener
+import java.beans.XMLEncoder
+import java.io.*
+import java.lang.Exception
+import kotlin.test.*
+import kotlin.text.RegexOption.*
+
+class RegexTest {
+
+    @Test
+    fun whenRegexIsInstantiated_thenIsEqualToToRegexMethod() {
+        val pattern = """a([bc]+)d?\\"""
+
+        assertEquals(Regex.fromLiteral(pattern).pattern, pattern)
+        assertEquals(pattern, Regex(pattern).pattern)
+        assertEquals(pattern, pattern.toRegex().pattern)
+    }
+
+    @Test
+    fun whenRegexMatches_thenResultIsTrue() {
+        val regex = """a([bc]+)d?""".toRegex()
+
+        assertTrue(regex.containsMatchIn("xabcdy"))
+        assertTrue(regex.matches("abcd"))
+        assertFalse(regex matches "xabcdy")
+    }
+
+    @Test
+    fun givenCompletelyMatchingRegex_whenMatchResult_thenDestructuring() {
+        val regex = """a([bc]+)d?""".toRegex()
+
+        assertNull(regex.matchEntire("xabcdy"))
+
+        val matchResult = regex.matchEntire("abbccbbd")
+
+        assertNotNull(matchResult)
+        assertEquals(matchResult!!.value, matchResult.groupValues[0])
+        assertEquals(matchResult.destructured.toList(), matchResult.groupValues.drop(1))
+        assertEquals("bbccbb", matchResult.destructured.component1())
+        assertNull(matchResult.next())
+    }
+
+    @Test
+    fun givenPartiallyMatchingRegex_whenMatchResult_thenGroups() {
+        val regex = """a([bc]+)d?""".toRegex()
+        var matchResult = regex.find("abcb abbd")
+
+        assertNotNull(matchResult)
+        assertEquals(matchResult!!.value, matchResult.groupValues[0])
+        assertEquals("abcb", matchResult.value)
+        assertEquals(IntRange(0, 3), matchResult.range)
+        assertEquals(listOf("abcb", "bcb"), matchResult.groupValues)
+        assertEquals(matchResult.destructured.toList(), matchResult.groupValues.drop(1))
+
+        matchResult = matchResult.next()
+
+        assertNotNull(matchResult)
+        assertEquals("abbd", matchResult!!.value)
+        assertEquals("bb", matchResult.groupValues[1])
+
+        matchResult = matchResult.next()
+
+        assertNull(matchResult)
+    }
+
+    @Test
+    fun givenPartiallyMatchingRegex_whenMatchResult_thenDestructuring() {
+        val regex = """([\w\s]+) is (\d+) years old""".toRegex()
+        val matchResult = regex.find("Mickey Mouse is 95 years old")
+        val (name, age) = matchResult!!.destructured
+
+        assertEquals("Mickey Mouse", name)
+        assertEquals("95", age)
+    }
+
+    @Test
+    fun givenNonMatchingRegex_whenFindCalled_thenNull() {
+        val regex = """a([bc]+)d?""".toRegex()
+        val matchResult = regex.find("foo")
+
+        assertNull(matchResult)
+    }
+
+    @Test
+    fun givenNonMatchingRegex_whenFindAllCalled_thenEmptySet() {
+        val regex = """a([bc]+)d?""".toRegex()
+        val matchResults = regex.findAll("foo")
+
+        assertNotNull(matchResults)
+        assertTrue(matchResults.none())
+    }
+
+    @Test
+    fun whenReplace_thenReplacement() {
+        val regex = """(red|green|blue)""".toRegex()
+        val beautiful = "Roses are red, Violets are blue"
+        val grim = regex.replace(beautiful, "dark")
+        val shiny = regex.replaceFirst(beautiful, "rainbow")
+
+        assertEquals("Roses are dark, Violets are dark", grim)
+        assertEquals("Roses are rainbow, Violets are blue", shiny)
+    }
+
+    @Test
+    fun whenComplexReplace_thenReplacement() {
+        val regex = """(red|green|blue)""".toRegex()
+        val beautiful = "Roses are red, Violets are blue"
+        val reallyBeautiful = regex.replace(beautiful) {
+            matchResult ->  matchResult.value.toUpperCase() + "!"
+        }
+
+        assertEquals("Roses are RED!, Violets are BLUE!", reallyBeautiful)
+    }
+
+    @Test
+    fun whenSplit_thenList() {
+        val regex = """\W+""".toRegex()
+        val beautiful = "Roses are red, Violets are blue"
+
+        assertEquals(listOf("Roses", "are", "red", "Violets", "are", "blue"), regex.split(beautiful))
+        assertEquals(listOf("Roses", "are", "red", "Violets are blue"), regex.split(beautiful, 4))
+        assertEquals(regex.toPattern().split(beautiful).asList(), regex.split(beautiful))
+    }
+
+}
--- a/guava/src/main/java/org/baeldung/guava/memoizer/CostlySupplier.java
+++ b/guava/src/main/java/org/baeldung/guava/memoizer/CostlySupplier.java
@ -0,0 +1,17 @@
+package org.baeldung.guava.memoizer;
+
+import java.math.BigInteger;
+import java.util.Random;
+import java.util.concurrent.TimeUnit;
+
+public class CostlySupplier {
+
+    public static BigInteger generateBigNumber() {
+        try {
+            TimeUnit.SECONDS.sleep(2);
+        } catch (InterruptedException e) {
+        }
+        return new BigInteger("12345");
+    }
+
+}
--- a/guava/src/main/java/org/baeldung/guava/memoizer/Factorial.java
+++ b/guava/src/main/java/org/baeldung/guava/memoizer/Factorial.java
@ -0,0 +1,22 @@
+package org.baeldung.guava.memoizer;
+
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+
+import java.math.BigInteger;
+
+public class Factorial {
+
+    private static LoadingCache<Integer, BigInteger> memo = CacheBuilder.newBuilder()
+            .build(CacheLoader.from(Factorial::getFactorial));
+
+    public static BigInteger getFactorial(int n) {
+        if (n == 0) {
+            return BigInteger.ONE;
+        } else {
+            return BigInteger.valueOf(n).multiply(memo.getUnchecked(n - 1));
+        }
+    }
+
+}
--- a/guava/src/main/java/org/baeldung/guava/memoizer/FibonacciSequence.java
+++ b/guava/src/main/java/org/baeldung/guava/memoizer/FibonacciSequence.java
@ -0,0 +1,26 @@
+package org.baeldung.guava.memoizer;
+
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+
+import java.math.BigInteger;
+import java.util.concurrent.TimeUnit;
+
+public class FibonacciSequence {
+
+    private static LoadingCache<Integer, BigInteger> memo = CacheBuilder.newBuilder()
+            .maximumSize(100)
+            .build(CacheLoader.from(FibonacciSequence::getFibonacciNumber));
+
+    public static BigInteger getFibonacciNumber(int n) {
+        if (n == 0) {
+            return BigInteger.ZERO;
+        } else if (n == 1) {
+            return BigInteger.ONE;
+        } else {
+            return memo.getUnchecked(n - 1).add(memo.getUnchecked(n - 2));
+        }
+    }
+
+}
--- a/guava/src/test/java/org/baeldung/guava/GuavaMemoizerUnitTest.java
+++ b/guava/src/test/java/org/baeldung/guava/GuavaMemoizerUnitTest.java
@ -0,0 +1,92 @@
+package org.baeldung.guava;
+
+import com.google.common.base.Suppliers;
+import org.baeldung.guava.memoizer.CostlySupplier;
+import org.baeldung.guava.memoizer.Factorial;
+import org.baeldung.guava.memoizer.FibonacciSequence;
+import org.junit.Test;
+
+import java.math.BigInteger;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
+
+import static org.hamcrest.core.Is.is;
+import static org.hamcrest.core.IsEqual.equalTo;
+import static org.hamcrest.number.IsCloseTo.closeTo;
+import static org.junit.Assert.assertThat;
+
+public class GuavaMemoizerUnitTest {
+
+    @Test
+    public void givenInteger_whenGetFibonacciNumber_thenShouldCalculateFibonacciNumber() {
+        // given
+        int n = 95;
+
+        // when
+        BigInteger fibonacciNumber = FibonacciSequence.getFibonacciNumber(n);
+
+        // then
+        BigInteger expectedFibonacciNumber = new BigInteger("31940434634990099905");
+        assertThat(fibonacciNumber, is(equalTo(expectedFibonacciNumber)));
+    }
+
+    @Test
+    public void givenInteger_whenGetFactorial_thenShouldCalculateFactorial() {
+        // given
+        int n = 95;
+
+        // when
+        BigInteger factorial = Factorial.getFactorial(n);
+
+        // then
+        BigInteger expectedFactorial = new BigInteger("10329978488239059262599702099394727095397746340117372869212250571234293987594703124871765375385424468563282236864226607350415360000000000000000000000");
+        assertThat(factorial, is(equalTo(expectedFactorial)));
+    }
+
+    @Test
+    public void givenMemoizedSupplier_whenGet_thenSubsequentGetsAreFast() {
+        // given
+        Supplier<BigInteger> memoizedSupplier;
+        memoizedSupplier = Suppliers.memoize(CostlySupplier::generateBigNumber);
+
+        // when
+        BigInteger expectedValue = new BigInteger("12345");
+        assertSupplierGetExecutionResultAndDuration(memoizedSupplier, expectedValue, 2000D);
+
+        // then
+        assertSupplierGetExecutionResultAndDuration(memoizedSupplier, expectedValue, 0D);
+        assertSupplierGetExecutionResultAndDuration(memoizedSupplier, expectedValue, 0D);
+    }
+
+    @Test
+    public void givenMemoizedSupplierWithExpiration_whenGet_thenSubsequentGetsBeforeExpiredAreFast() throws InterruptedException {
+        // given
+        Supplier<BigInteger> memoizedSupplier;
+        memoizedSupplier = Suppliers.memoizeWithExpiration(CostlySupplier::generateBigNumber, 3, TimeUnit.SECONDS);
+
+        // when
+        BigInteger expectedValue = new BigInteger("12345");
+        assertSupplierGetExecutionResultAndDuration(memoizedSupplier, expectedValue, 2000D);
+
+        // then
+        assertSupplierGetExecutionResultAndDuration(memoizedSupplier, expectedValue, 0D);
+        // add one more second until memoized Supplier is evicted from memory
+        TimeUnit.SECONDS.sleep(1);
+        assertSupplierGetExecutionResultAndDuration(memoizedSupplier, expectedValue, 2000D);
+    }
+
+    private <T> void assertSupplierGetExecutionResultAndDuration(Supplier<T> supplier,
+                                                                 T expectedValue,
+                                                                 double expectedDurationInMs) {
+        Instant start = Instant.now();
+        T value = supplier.get();
+        Long durationInMs = Duration.between(start, Instant.now()).toMillis();
+        double marginOfErrorInMs = 100D;
+
+        assertThat(value, is(equalTo(expectedValue)));
+        assertThat(durationInMs.doubleValue(), is(closeTo(expectedDurationInMs, marginOfErrorInMs)));
+    }
+
+}
--- a/hibernate5/src/main/java/com/baeldung/hibernate/HibernateUtil.java
+++ b/hibernate5/src/main/java/com/baeldung/hibernate/HibernateUtil.java
@ -81,6 +81,7 @@ public class HibernateUtil {
        metadataSources.addAnnotatedClass(Bag.class);
        metadataSources.addAnnotatedClass(PointEntity.class);
        metadataSources.addAnnotatedClass(PolygonEntity.class);
+        metadataSources.addAnnotatedClass(com.baeldung.hibernate.pojo.Person.class);

        Metadata metadata = metadataSources.buildMetadata();
        return metadata.getSessionFactoryBuilder()
--- a/hibernate5/src/main/java/com/baeldung/hibernate/converters/PersonNameConverter.java
+++ b/hibernate5/src/main/java/com/baeldung/hibernate/converters/PersonNameConverter.java
@ -0,0 +1,43 @@
+package com.baeldung.hibernate.converters;
+
+import javax.persistence.AttributeConverter;
+import javax.persistence.Converter;
+
+import com.baeldung.hibernate.pojo.PersonName;
+
+@Converter
+public class PersonNameConverter implements AttributeConverter<PersonName, String> {
+
+    private static final String SEPARATOR = ", ";
+
+    @Override
+    public String convertToDatabaseColumn(PersonName person) {
+        StringBuilder sb = new StringBuilder();
+        if (person.getSurname() != null) {
+            sb.append(person.getSurname());
+            sb.append(SEPARATOR);
+        }
+
+        if (person.getName() != null) {
+            sb.append(person.getName());
+        }
+
+        return sb.toString();
+    }
+
+    @Override
+    public PersonName convertToEntityAttribute(String dbPerson) {
+        String[] pieces = dbPerson.split(SEPARATOR);
+
+        if (pieces == null || pieces.length != 2) {
+            return null;
+        }
+
+        PersonName personName = new PersonName();
+        personName.setSurname(pieces[0]);
+        personName.setName(pieces[1]);
+
+        return personName;
+    }
+
+}
--- a/hibernate5/src/main/java/com/baeldung/hibernate/interceptors/CustomInterceptorImpl.java
+++ b/hibernate5/src/main/java/com/baeldung/hibernate/interceptors/CustomInterceptorImpl.java
@ -9,7 +9,7 @@ import org.hibernate.Interceptor;
 import org.hibernate.Transaction;
 import org.hibernate.type.Type;

-public class CustomInterceptorImpl implements Interceptor {
+public class CustomInterceptorImpl implements Interceptor, Serializable {

    @Override
    public boolean onLoad(Object entity, Serializable id, Object[] state, String[] propertyNames, Type[] types) throws CallbackException {
--- a/hibernate5/src/main/java/com/baeldung/hibernate/pojo/Person.java
+++ b/hibernate5/src/main/java/com/baeldung/hibernate/pojo/Person.java
@ -0,0 +1,32 @@
+package com.baeldung.hibernate.pojo;
+
+import javax.persistence.Convert;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+
+import com.baeldung.hibernate.converters.PersonNameConverter;
+
+@Entity(name = "PersonTable")
+public class Person {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    @Convert(converter = PersonNameConverter.class)
+    private PersonName personName;
+
+    public PersonName getPersonName() {
+        return personName;
+    }
+
+    public void setPersonName(PersonName personName) {
+        this.personName = personName;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+}
--- a/hibernate5/src/main/java/com/baeldung/hibernate/pojo/PersonName.java
+++ b/hibernate5/src/main/java/com/baeldung/hibernate/pojo/PersonName.java
@ -0,0 +1,29 @@
+package com.baeldung.hibernate.pojo;
+
+import java.io.Serializable;
+
+public class PersonName implements Serializable {
+
+    private static final long serialVersionUID = 7883094644631050150L;
+
+    private String name;
+
+    private String surname;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+
+}
--- a/hibernate5/src/test/java/com/baeldung/hibernate/converter/PersonNameConverterTest.java
+++ b/hibernate5/src/test/java/com/baeldung/hibernate/converter/PersonNameConverterTest.java
@ -0,0 +1,74 @@
+package com.baeldung.hibernate.converter;
+
+import java.io.IOException;
+
+import org.hibernate.Session;
+import org.hibernate.Transaction;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.hibernate.HibernateUtil;
+import com.baeldung.hibernate.pojo.Person;
+import com.baeldung.hibernate.pojo.PersonName;
+
+import static org.junit.Assert.assertEquals;
+
+public class PersonNameConverterTest {
+
+    private Session session;
+    private Transaction transaction;
+
+    @Before
+    public void setUp() throws IOException {
+        session = HibernateUtil.getSessionFactory()
+            .openSession();
+        transaction = session.beginTransaction();
+
+        session.createNativeQuery("delete from personTable")
+            .executeUpdate();
+
+        transaction.commit();
+        transaction = session.beginTransaction();
+    }
+
+    @After
+    public void tearDown() {
+        transaction.rollback();
+        session.close();
+    }
+
+    @Test
+    public void givenPersonName_WhenSaving_ThenNameAndSurnameConcat() {
+        final String name = "name";
+        final String surname = "surname";
+
+        PersonName personName = new PersonName();
+        personName.setName(name);
+        personName.setSurname(surname);
+
+        Person person = new Person();
+        person.setPersonName(personName);
+
+        Long id = (Long) session.save(person);
+
+        session.flush();
+        session.clear();
+
+        String dbPersonName = (String) session.createNativeQuery("select p.personName from PersonTable p where p.id = :id")
+            .setParameter("id", id)
+            .getSingleResult();
+
+        assertEquals(surname + ", " + name, dbPersonName);
+
+        Person dbPerson = session.createNativeQuery("select * from PersonTable p where p.id = :id", Person.class)
+            .setParameter("id", id)
+            .getSingleResult();
+
+        assertEquals(dbPerson.getPersonName()
+            .getName(), name);
+        assertEquals(dbPerson.getPersonName()
+            .getSurname(), surname);
+    }
+
+}
--- a/influxdb/README.md
+++ b/influxdb/README.md
@ -2,7 +2,6 @@

 ### Relevant Article:
 - [Introduction to using InfluxDB with Java](http://www.baeldung.com/using-influxdb-with-java/)
- [Using InfluxDB with Java](http://www.baeldung.com/java-influxdb)

 ### Overview
 This Maven project contains the Java code for the article linked above.
--- a/influxdb/src/test/java/com/baeldung/influxdb/InfluxDBConnectionLiveTest.java
+++ b/influxdb/src/test/java/com/baeldung/influxdb/InfluxDBConnectionLiveTest.java
@ -8,7 +8,6 @@ import org.influxdb.dto.*;
 import org.influxdb.impl.InfluxDBResultMapper;
 import org.junit.Test;

-import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.TimeUnit;

@ -103,7 +102,7 @@ public class InfluxDBConnectionLiveTest {
        // another brief pause.
        Thread.sleep(10);

-        List<MemoryPoint> memoryPointList = getPoints(connection, "Select * from memory", "baeldung");
+        List<com.baeldung.influxdb.MemoryPoint> memoryPointList = getPoints(connection, "Select * from memory", "baeldung");

        assertEquals(10, memoryPointList.size());

--- a/jackson/pom.xml
+++ b/jackson/pom.xml
@ -129,7 +129,7 @@

    <properties>
        <!-- marshalling -->
-        <jackson.version>2.9.2</jackson.version>
+        <jackson.version>2.9.4</jackson.version>

        <!-- util -->
        <guava.version>19.0</guava.version>
--- a/javaxval/pom.xml
+++ b/javaxval/pom.xml
@ -6,10 +6,11 @@
    <version>0.1-SNAPSHOT</version>

    <properties>
-        <validation-api.version>2.0.0.Final</validation-api.version>
-        <hibernate-validator.version>6.0.2.Final</hibernate-validator.version>
+        <validation-api.version>2.0.1.Final</validation-api.version>
+        <hibernate-validator.version>6.0.7.Final</hibernate-validator.version>
        <javax.el-api.version>3.0.0</javax.el-api.version>
        <javax.el.version>2.2.6</javax.el.version>
+        <org.springframework.version>5.0.2.RELEASE</org.springframework.version>
    </properties>


@ -21,12 +22,6 @@

    <dependencies>

-        <dependency>
-            <groupId>javax.validation</groupId>
-            <artifactId>validation-api</artifactId>
-            <version>${validation-api.version}</version>
-        </dependency>
-
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
@ -50,6 +45,16 @@
            <artifactId>javax.el</artifactId>
            <version>${javax.el.version}</version>
        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-context</artifactId>
+            <version>${org.springframework.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-test</artifactId>
+            <version>${org.springframework.version}</version>
+        </dependency>

    </dependencies>

--- a/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/MethodValidationConfig.java
+++ b/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/MethodValidationConfig.java
@ -0,0 +1,38 @@
+package org.baeldung.javaxval.methodvalidation;
+
+import org.baeldung.javaxval.methodvalidation.model.Customer;
+import org.baeldung.javaxval.methodvalidation.model.Reservation;
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Scope;
+import org.springframework.validation.beanvalidation.MethodValidationPostProcessor;
+
+import java.time.LocalDate;
+
+@Configuration
+@ComponentScan({ "org.baeldung.javaxval.methodvalidation.model" })
+public class MethodValidationConfig {
+
+    @Bean
+    public MethodValidationPostProcessor methodValidationPostProcessor() {
+        return new MethodValidationPostProcessor();
+    }
+
+    @Bean("customer")
+    @Scope(BeanDefinition.SCOPE_PROTOTYPE)
+    public Customer customer(String firstName, String lastName) {
+
+        Customer customer = new Customer(firstName, lastName);
+        return customer;
+    }
+
+    @Bean("reservation")
+    @Scope(BeanDefinition.SCOPE_PROTOTYPE)
+    public Reservation reservation(LocalDate begin, LocalDate end, Customer customer, int room) {
+
+        Reservation reservation = new Reservation(begin, end, customer, room);
+        return reservation;
+    }
+}
--- a/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/constraints/ConsistentDateParameterValidator.java
+++ b/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/constraints/ConsistentDateParameterValidator.java
@ -0,0 +1,25 @@
+package org.baeldung.javaxval.methodvalidation.constraints;
+
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+import javax.validation.constraintvalidation.SupportedValidationTarget;
+import javax.validation.constraintvalidation.ValidationTarget;
+import java.time.LocalDate;
+
+@SupportedValidationTarget(ValidationTarget.PARAMETERS)
+public class ConsistentDateParameterValidator implements ConstraintValidator<ConsistentDateParameters, Object[]> {
+
+    @Override
+    public boolean isValid(Object[] value, ConstraintValidatorContext context) {
+
+        if (value[0] == null || value[1] == null) {
+            return true;
+        }
+
+        if (!(value[0] instanceof LocalDate) || !(value[1] instanceof LocalDate)) {
+            throw new IllegalArgumentException("Illegal method signature, expected two parameters of type LocalDate.");
+        }
+
+        return ((LocalDate) value[0]).isAfter(LocalDate.now()) && ((LocalDate) value[0]).isBefore((LocalDate) value[1]);
+    }
+}
--- a/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/constraints/ConsistentDateParameters.java
+++ b/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/constraints/ConsistentDateParameters.java
@ -0,0 +1,23 @@
+package org.baeldung.javaxval.methodvalidation.constraints;
+
+import javax.validation.Constraint;
+import javax.validation.Payload;
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.*;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+@Constraint(validatedBy = ConsistentDateParameterValidator.class)
+@Target({ METHOD, CONSTRUCTOR })
+@Retention(RUNTIME)
+@Documented
+public @interface ConsistentDateParameters {
+
+    String message() default "End date must be after begin date and both must be in the future";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+}
--- a/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/constraints/ValidReservation.java
+++ b/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/constraints/ValidReservation.java
@ -0,0 +1,24 @@
+package org.baeldung.javaxval.methodvalidation.constraints;
+
+import javax.validation.Constraint;
+import javax.validation.Payload;
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.CONSTRUCTOR;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+@Constraint(validatedBy = ValidReservationValidator.class)
+@Target({ METHOD, CONSTRUCTOR })
+@Retention(RUNTIME)
+@Documented
+public @interface ValidReservation {
+
+    String message() default "End date must be after begin date and both must be in the future, room number must be bigger than 0";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+}
--- a/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/constraints/ValidReservationValidator.java
+++ b/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/constraints/ValidReservationValidator.java
@ -0,0 +1,32 @@
+package org.baeldung.javaxval.methodvalidation.constraints;
+
+import org.baeldung.javaxval.methodvalidation.model.Reservation;
+
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+import java.time.LocalDate;
+
+public class ValidReservationValidator implements ConstraintValidator<ValidReservation, Reservation> {
+
+    @Override
+    public boolean isValid(Reservation reservation, ConstraintValidatorContext context) {
+
+        if (reservation == null) {
+            return true;
+        }
+
+        if (!(reservation instanceof Reservation)) {
+            throw new IllegalArgumentException("Illegal method signature, expected parameter of type Reservation.");
+        }
+
+        if (reservation.getBegin() == null || reservation.getEnd() == null || reservation.getCustomer() == null) {
+            return false;
+        }
+
+        return (reservation.getBegin()
+            .isAfter(LocalDate.now())
+            && reservation.getBegin()
+                .isBefore(reservation.getEnd())
+            && reservation.getRoom() > 0);
+    }
+}
--- a/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/model/Customer.java
+++ b/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/model/Customer.java
@ -0,0 +1,41 @@
+package org.baeldung.javaxval.methodvalidation.model;
+
+import org.springframework.validation.annotation.Validated;
+
+import javax.validation.constraints.NotNull;
+import javax.validation.constraints.Size;
+
+@Validated
+public class Customer {
+
+    @Size(min = 5, max = 200)
+    private String firstName;
+
+    @Size(min = 5, max = 200)
+    private String lastName;
+
+    public Customer(@Size(min = 5, max = 200) @NotNull String firstName, @Size(min = 5, max = 200) @NotNull String lastName) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+    }
+
+    public Customer() {
+
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+}
--- a/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/model/Reservation.java
+++ b/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/model/Reservation.java
@ -0,0 +1,64 @@
+package org.baeldung.javaxval.methodvalidation.model;
+
+import org.baeldung.javaxval.methodvalidation.constraints.ConsistentDateParameters;
+import org.baeldung.javaxval.methodvalidation.constraints.ValidReservation;
+import org.springframework.validation.annotation.Validated;
+
+import javax.validation.Valid;
+import javax.validation.constraints.Positive;
+import java.time.LocalDate;
+
+@Validated
+public class Reservation {
+
+    private LocalDate begin;
+
+    private LocalDate end;
+
+    @Valid
+    private Customer customer;
+
+    @Positive
+    private int room;
+
+    @ConsistentDateParameters
+    @ValidReservation
+    public Reservation(LocalDate begin, LocalDate end, Customer customer, int room) {
+        this.begin = begin;
+        this.end = end;
+        this.customer = customer;
+        this.room = room;
+    }
+
+    public LocalDate getBegin() {
+        return begin;
+    }
+
+    public void setBegin(LocalDate begin) {
+        this.begin = begin;
+    }
+
+    public LocalDate getEnd() {
+        return end;
+    }
+
+    public void setEnd(LocalDate end) {
+        this.end = end;
+    }
+
+    public Customer getCustomer() {
+        return customer;
+    }
+
+    public void setCustomer(Customer customer) {
+        this.customer = customer;
+    }
+
+    public int getRoom() {
+        return room;
+    }
+
+    public void setRoom(int room) {
+        this.room = room;
+    }
+}
--- a/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/model/ReservationManagement.java
+++ b/javaxval/src/main/java/org/baeldung/javaxval/methodvalidation/model/ReservationManagement.java
@ -0,0 +1,50 @@
+package org.baeldung.javaxval.methodvalidation.model;
+
+import org.baeldung.javaxval.methodvalidation.constraints.ConsistentDateParameters;
+import org.baeldung.javaxval.methodvalidation.constraints.ValidReservation;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationContext;
+import org.springframework.stereotype.Controller;
+import org.springframework.validation.annotation.Validated;
+
+import javax.validation.Valid;
+import javax.validation.constraints.*;
+import java.time.LocalDate;
+import java.util.List;
+
+@Controller
+@Validated
+public class ReservationManagement {
+
+    @Autowired
+    private ApplicationContext applicationContext;
+
+    @ConsistentDateParameters
+    public void createReservation(LocalDate begin, LocalDate end, @NotNull Customer customer) {
+
+        // ...
+    }
+
+    public void createReservation(@NotNull @Future LocalDate begin, @Min(1) int duration, @NotNull Customer customer) {
+
+        // ...
+    }
+
+    public void createReservation(@Valid Reservation reservation) {
+
+        // ...
+    }
+
+    @NotNull
+    @Size(min = 1)
+    public List<@NotNull Customer> getAllCustomers() {
+
+        return null;
+    }
+
+    @Valid
+    public Reservation getReservationById(int id) {
+
+        return null;
+    }
+}
--- a/javaxval/src/test/java/org/baeldung/javaxval/methodvalidation/ContainerValidationIntegrationTest.java
+++ b/javaxval/src/test/java/org/baeldung/javaxval/methodvalidation/ContainerValidationIntegrationTest.java
@ -0,0 +1,97 @@
+package org.baeldung.javaxval.methodvalidation;
+
+import org.baeldung.javaxval.methodvalidation.model.Customer;
+import org.baeldung.javaxval.methodvalidation.model.Reservation;
+import org.baeldung.javaxval.methodvalidation.model.ReservationManagement;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.support.AnnotationConfigContextLoader;
+
+import javax.validation.ConstraintViolationException;
+import java.time.LocalDate;
+import java.util.List;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = { MethodValidationConfig.class }, loader = AnnotationConfigContextLoader.class)
+public class ContainerValidationIntegrationTest {
+
+    @Autowired
+    ReservationManagement reservationManagement;
+
+    @Rule
+    public final ExpectedException exception = ExpectedException.none();
+
+    @Test
+    public void whenValidationWithInvalidMethodParameters_thenConstraintViolationException() {
+
+        exception.expect(ConstraintViolationException.class);
+        reservationManagement.createReservation(LocalDate.now(), 0, null);
+    }
+
+    @Test
+    public void whenValidationWithValidMethodParameters_thenNoException() {
+
+        reservationManagement.createReservation(LocalDate.now()
+            .plusDays(1), 1, new Customer("William", "Smith"));
+    }
+
+    @Test
+    public void whenCrossParameterValidationWithInvalidParameters_thenConstraintViolationException() {
+
+        exception.expect(ConstraintViolationException.class);
+        reservationManagement.createReservation(LocalDate.now(), LocalDate.now(), null);
+    }
+
+    @Test
+    public void whenCrossParameterValidationWithValidParameters_thenNoException() {
+
+        reservationManagement.createReservation(LocalDate.now()
+            .plusDays(1),
+            LocalDate.now()
+                .plusDays(2),
+            new Customer("William", "Smith"));
+    }
+
+    @Test
+    public void whenValidationWithInvalidReturnValue_thenConstraintViolationException() {
+
+        exception.expect(ConstraintViolationException.class);
+        List<Customer> list = reservationManagement.getAllCustomers();
+    }
+
+    @Test
+    public void whenValidationWithInvalidCascadedValue_thenConstraintViolationException() {
+
+        Customer customer = new Customer();
+        customer.setFirstName("John");
+        customer.setLastName("Doe");
+        Reservation reservation = new Reservation(LocalDate.now()
+            .plusDays(1),
+            LocalDate.now()
+                .plusDays(2),
+            customer, 1);
+
+        exception.expect(ConstraintViolationException.class);
+        reservationManagement.createReservation(reservation);
+    }
+
+    @Test
+    public void whenValidationWithValidCascadedValue_thenCNoException() {
+
+        Customer customer = new Customer();
+        customer.setFirstName("William");
+        customer.setLastName("Smith");
+        Reservation reservation = new Reservation(LocalDate.now()
+            .plusDays(1),
+            LocalDate.now()
+                .plusDays(2),
+            customer, 1);
+
+        reservationManagement.createReservation(reservation);
+    }
+}
--- a/javaxval/src/test/java/org/baeldung/javaxval/methodvalidation/ValidationIntegrationTest.java
+++ b/javaxval/src/test/java/org/baeldung/javaxval/methodvalidation/ValidationIntegrationTest.java
@ -0,0 +1,209 @@
+package org.baeldung.javaxval.methodvalidation;
+
+import org.baeldung.javaxval.methodvalidation.model.Customer;
+import org.baeldung.javaxval.methodvalidation.model.Reservation;
+import org.baeldung.javaxval.methodvalidation.model.ReservationManagement;
+import org.junit.Before;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+import javax.validation.ConstraintViolation;
+import javax.validation.Validation;
+import javax.validation.ValidatorFactory;
+import javax.validation.executable.ExecutableValidator;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+import java.time.LocalDate;
+import java.util.Collections;
+import java.util.Set;
+
+public class ValidationIntegrationTest {
+
+    private ExecutableValidator executableValidator;
+
+    @Before
+    public void getExecutableValidator() {
+
+        ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
+        this.executableValidator = factory.getValidator()
+            .forExecutables();
+    }
+
+    @Test
+    public void whenValidationWithInvalidMethodParameters_thenCorrectNumberOfVoilations() throws NoSuchMethodException {
+
+        ReservationManagement object = new ReservationManagement();
+        Method method = ReservationManagement.class.getMethod("createReservation", LocalDate.class, int.class, Customer.class);
+        Object[] parameterValues = { LocalDate.now(), 0, null };
+        Set<ConstraintViolation<ReservationManagement>> violations = executableValidator.validateParameters(object, method, parameterValues);
+
+        assertEquals(3, violations.size());
+    }
+
+    @Test
+    public void whenValidationWithValidMethodParameters_thenZeroVoilations() throws NoSuchMethodException {
+
+        ReservationManagement object = new ReservationManagement();
+        Method method = ReservationManagement.class.getMethod("createReservation", LocalDate.class, int.class, Customer.class);
+        Object[] parameterValues = { LocalDate.now()
+            .plusDays(1), 1, new Customer("John", "Doe") };
+        Set<ConstraintViolation<ReservationManagement>> violations = executableValidator.validateParameters(object, method, parameterValues);
+
+        assertEquals(0, violations.size());
+    }
+
+    @Test
+    public void whenCrossParameterValidationWithInvalidParameters_thenCorrectNumberOfVoilations() throws NoSuchMethodException {
+
+        ReservationManagement object = new ReservationManagement();
+        Method method = ReservationManagement.class.getMethod("createReservation", LocalDate.class, LocalDate.class, Customer.class);
+        Object[] parameterValues = { LocalDate.now(), LocalDate.now(), new Customer("John", "Doe") };
+        Set<ConstraintViolation<ReservationManagement>> violations = executableValidator.validateParameters(object, method, parameterValues);
+
+        assertEquals(1, violations.size());
+    }
+
+    @Test
+    public void whenCrossParameterValidationWithValidParameters_thenZeroVoilations() throws NoSuchMethodException {
+
+        ReservationManagement object = new ReservationManagement();
+        Method method = ReservationManagement.class.getMethod("createReservation", LocalDate.class, LocalDate.class, Customer.class);
+        Object[] parameterValues = { LocalDate.now()
+            .plusDays(1),
+                LocalDate.now()
+                    .plusDays(2),
+                new Customer("John", "Doe") };
+        Set<ConstraintViolation<ReservationManagement>> violations = executableValidator.validateParameters(object, method, parameterValues);
+
+        assertEquals(0, violations.size());
+    }
+
+    @Test
+    public void whenValidationWithInvalidConstructorParameters_thenCorrectNumberOfVoilations() throws NoSuchMethodException {
+
+        Constructor<Customer> constructor = Customer.class.getConstructor(String.class, String.class);
+        Object[] parameterValues = { "John", "Doe" };
+        Set<ConstraintViolation<Customer>> violations = executableValidator.validateConstructorParameters(constructor, parameterValues);
+
+        assertEquals(2, violations.size());
+    }
+
+    @Test
+    public void whenValidationWithValidConstructorParameters_thenZeroVoilations() throws NoSuchMethodException {
+
+        Constructor<Customer> constructor = Customer.class.getConstructor(String.class, String.class);
+        Object[] parameterValues = { "William", "Smith" };
+        Set<ConstraintViolation<Customer>> violations = executableValidator.validateConstructorParameters(constructor, parameterValues);
+
+        assertEquals(0, violations.size());
+    }
+
+    @Test
+    public void whenCrossParameterValidationWithInvalidConstructorParameters_thenCorrectNumberOfVoilations() throws NoSuchMethodException {
+
+        Constructor<Reservation> constructor = Reservation.class.getConstructor(LocalDate.class, LocalDate.class, Customer.class, int.class);
+        Object[] parameterValues = { LocalDate.now(), LocalDate.now(), new Customer("William", "Smith"), 1 };
+        Set<ConstraintViolation<Reservation>> violations = executableValidator.validateConstructorParameters(constructor, parameterValues);
+
+        assertEquals(1, violations.size());
+    }
+
+    @Test
+    public void whenCrossParameterValidationWithValidConstructorParameters_thenZeroVoilations() throws NoSuchMethodException {
+
+        Constructor<Reservation> constructor = Reservation.class.getConstructor(LocalDate.class, LocalDate.class, Customer.class, int.class);
+        Object[] parameterValues = { LocalDate.now()
+            .plusDays(1),
+                LocalDate.now()
+                    .plusDays(2),
+                new Customer("William", "Smith"), 1 };
+        Set<ConstraintViolation<Reservation>> violations = executableValidator.validateConstructorParameters(constructor, parameterValues);
+
+        assertEquals(0, violations.size());
+    }
+
+    @Test
+    public void whenValidationWithInvalidReturnValue_thenCorrectNumberOfVoilations() throws NoSuchMethodException {
+
+        ReservationManagement object = new ReservationManagement();
+        Method method = ReservationManagement.class.getMethod("getAllCustomers");
+        Object returnValue = Collections.<Customer> emptyList();
+        Set<ConstraintViolation<ReservationManagement>> violations = executableValidator.validateReturnValue(object, method, returnValue);
+
+        assertEquals(1, violations.size());
+    }
+
+    @Test
+    public void whenValidationWithValidReturnValue_thenZeroVoilations() throws NoSuchMethodException {
+
+        ReservationManagement object = new ReservationManagement();
+        Method method = ReservationManagement.class.getMethod("getAllCustomers");
+        Object returnValue = Collections.singletonList(new Customer("William", "Smith"));
+        Set<ConstraintViolation<ReservationManagement>> violations = executableValidator.validateReturnValue(object, method, returnValue);
+
+        assertEquals(0, violations.size());
+    }
+
+    @Test
+    public void whenValidationWithInvalidConstructorReturnValue_thenCorrectNumberOfVoilations() throws NoSuchMethodException {
+
+        Constructor<Reservation> constructor = Reservation.class.getConstructor(LocalDate.class, LocalDate.class, Customer.class, int.class);
+        Reservation createdObject = new Reservation(LocalDate.now(), LocalDate.now(), new Customer("William", "Smith"), 0);
+        Set<ConstraintViolation<Reservation>> violations = executableValidator.validateConstructorReturnValue(constructor, createdObject);
+
+        assertEquals(1, violations.size());
+    }
+
+    @Test
+    public void whenValidationWithValidConstructorReturnValue_thenZeroVoilations() throws NoSuchMethodException {
+
+        Constructor<Reservation> constructor = Reservation.class.getConstructor(LocalDate.class, LocalDate.class, Customer.class, int.class);
+        Reservation createdObject = new Reservation(LocalDate.now()
+            .plusDays(1),
+            LocalDate.now()
+                .plusDays(2),
+            new Customer("William", "Smith"), 1);
+        Set<ConstraintViolation<Reservation>> violations = executableValidator.validateConstructorReturnValue(constructor, createdObject);
+
+        assertEquals(0, violations.size());
+    }
+
+    @Test
+    public void whenValidationWithInvalidCascadedValue_thenCorrectNumberOfVoilations() throws NoSuchMethodException {
+
+        ReservationManagement object = new ReservationManagement();
+        Method method = ReservationManagement.class.getMethod("createReservation", Reservation.class);
+        Customer customer = new Customer();
+        customer.setFirstName("John");
+        customer.setLastName("Doe");
+        Reservation reservation = new Reservation(LocalDate.now()
+            .plusDays(1),
+            LocalDate.now()
+                .plusDays(2),
+            customer, 1);
+        Object[] parameterValues = { reservation };
+        Set<ConstraintViolation<ReservationManagement>> violations = executableValidator.validateParameters(object, method, parameterValues);
+
+        assertEquals(2, violations.size());
+    }
+
+    @Test
+    public void whenValidationWithValidCascadedValue_thenCorrectNumberOfVoilations() throws NoSuchMethodException {
+
+        ReservationManagement object = new ReservationManagement();
+        Method method = ReservationManagement.class.getMethod("createReservation", Reservation.class);
+        Customer customer = new Customer();
+        customer.setFirstName("William");
+        customer.setLastName("Smith");
+        Reservation reservation = new Reservation(LocalDate.now()
+            .plusDays(1),
+            LocalDate.now()
+                .plusDays(2),
+            customer, 1);
+        Object[] parameterValues = { reservation };
+        Set<ConstraintViolation<ReservationManagement>> violations = executableValidator.validateParameters(object, method, parameterValues);
+
+        assertEquals(0, violations.size());
+    }
+
+}
--- a/jgroups/README.md
+++ b/jgroups/README.md
@ -0,0 +1,15 @@
+## Reliable Messaging with JGroups Tutorial Project
+
+### Relevant Article:
+- [Reliable Messaging with JGroups](http://www.baeldung.com/reliable-messaging-with-jgroups/)
+
+### Overview
+This Maven project contains the Java code for the article linked above.
+
+### Package Organization
+Java classes for the intro tutorial are in the org.baeldung.jgroups package.
+
+
+### Running the tests
+
+```
--- a/jgroups/pom.xml
+++ b/jgroups/pom.xml
@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>jgroups</artifactId>
+    <version>0.1-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <name>jgroups</name>
+    <description>Reliable Messaging with JGroups Tutorial</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.jgroups</groupId>
+            <artifactId>jgroups</artifactId>
+            <version>4.0.10.Final</version>
+        </dependency>
+
+        <dependency>
+            <groupId>commons-cli</groupId>
+            <artifactId>commons-cli</artifactId>
+            <version>1.4</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <java.version>1.8</java.version>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+</project>
--- a/jgroups/src/main/java/com/baeldung/jgroups/JGroupsMessenger.java
+++ b/jgroups/src/main/java/com/baeldung/jgroups/JGroupsMessenger.java
@ -0,0 +1,212 @@
+package com.baeldung.jgroups;
+
+import org.apache.commons.cli.*;
+import org.jgroups.*;
+import org.jgroups.util.Util;
+
+import java.io.*;
+import java.util.List;
+import java.util.Optional;
+
+public class JGroupsMessenger extends ReceiverAdapter {
+
+    private JChannel channel;
+    private String userName;
+    private String clusterName;
+    private View lastView;
+    private boolean running = true;
+
+    // Our shared state
+    private Integer messageCount = 0;
+
+    /**
+     * Connect to a JGroups cluster using command line options
+     * @param args command line arguments
+     * @throws Exception
+     */
+    private void start(String[] args) throws Exception {
+        processCommandline(args);
+
+        // Create the channel
+        // This file could be moved, or made a command line option.
+        channel = new JChannel("src/main/resources/udp.xml");
+
+        // Set a name
+        channel.name(userName);
+
+        // Register for callbacks
+        channel.setReceiver(this);
+
+        // Ignore our messages
+        channel.setDiscardOwnMessages(true);
+
+        // Connect
+        channel.connect(clusterName);
+
+        // Start state transfer
+        channel.getState(null, 0);
+
+        // Do the things
+        processInput();
+
+        // Clean up
+        channel.close();
+
+    }
+
+    /**
+     * Quick and dirty implementaton of commons cli for command line args
+     * @param args the command line args
+     * @throws ParseException
+     */
+    private void processCommandline(String[] args) throws ParseException {
+
+        // Options, parser, friendly help
+        Options options = new Options();
+        CommandLineParser parser = new DefaultParser();
+        HelpFormatter formatter = new HelpFormatter();
+
+        options.addOption("u", "user", true, "User name")
+            .addOption("c", "cluster", true, "Cluster name");
+
+        CommandLine line = parser.parse(options, args);
+
+        if (line.hasOption("user")) {
+            userName = line.getOptionValue("user");
+        } else {
+            formatter.printHelp("JGroupsMessenger: need a user name.\n", options);
+            System.exit(-1);
+        }
+
+        if (line.hasOption("cluster")) {
+            clusterName = line.getOptionValue("cluster");
+        } else {
+            formatter.printHelp("JGroupsMessenger: need a cluster name.\n", options);
+            System.exit(-1);
+        }
+    }
+
+    // Start it up
+    public static void main(String[] args) throws Exception {
+        new JGroupsMessenger().start(args);
+    }
+
+
+    @Override
+    public void viewAccepted(View newView) {
+
+        // Save view if this is the first
+        if (lastView == null) {
+            System.out.println("Received initial view:");
+            newView.forEach(System.out::println);
+        } else {
+            // Compare to last view
+            System.out.println("Received new view.");
+
+            List<Address> newMembers = View.newMembers(lastView, newView);
+            System.out.println("New members: ");
+            newMembers.forEach(System.out::println);
+
+            List<Address> exMembers = View.leftMembers(lastView, newView);
+            System.out.println("Exited members:");
+            exMembers.forEach(System.out::println);
+        }
+        lastView = newView;
+    }
+
+    /**
+     * Loop on console input until we see 'x' to exit
+     */
+    private void processInput() throws Exception {
+
+        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
+        while (running) {
+            try {
+
+                // Get a destination, <enter> means broadcast
+                Address destination = null;
+                System.out.print("Enter a destination: ");
+                System.out.flush();
+                String destinationName = in.readLine().toLowerCase();
+
+                if (destinationName.equals("x")) {
+                    running = false;
+                    continue;
+                } else if (!destinationName.isEmpty()) {
+                    destination = getAddress(destinationName)
+                      . orElseThrow(() -> new Exception("Destination not found"));
+                }
+
+                // Accept a string to send
+                System.out.print("Enter a message: ");
+                System.out.flush();
+                String line = in.readLine().toLowerCase();
+                sendMessage(destination, line);
+            } catch (IOException ioe) {
+                running = false;
+            }
+        }
+        System.out.println("Exiting.");
+    }
+
+    /**
+     * Send message from here
+     * @param destination the destination
+     * @param messageString the message
+     */
+    private void sendMessage(Address destination, String messageString) {
+        try {
+            System.out.println("Sending " + messageString + " to " + destination);
+            Message message = new Message(destination, messageString);
+            channel.send(message);
+        } catch (Exception exception) {
+            System.err.println("Exception sending message: " + exception.getMessage());
+            running = false;
+        }
+    }
+
+    @Override
+    public void receive(Message message) {
+        // Print source and dest with message
+        String line = "Message received from: " + message.getSrc() + " to: " + message.getDest() + " -> " + message.getObject();
+
+        // Only track the count of broadcast messages
+        // Tracking direct message would make for a pointless state
+        if (message.getDest() == null) {
+            messageCount++;
+            System.out.println("Message count: " + messageCount);
+        }
+
+        System.out.println(line);
+    }
+
+    @Override
+    public void getState(OutputStream output) throws Exception {
+        // Serialize into the stream
+        Util.objectToStream(messageCount, new DataOutputStream(output));
+    }
+
+    @Override
+    public void setState(InputStream input) {
+
+        // NOTE: since we know that incrementing the count and transferring the state
+        // is done inside the JChannel's thread, we don't have to worry about synchronizing
+        // messageCount. For production code it should be synchronized!
+        try {
+            // Deserialize
+            messageCount = Util.objectFromStream(new DataInputStream(input));
+        } catch (Exception e) {
+            System.out.println("Error deserialing state!");
+        }
+        System.out.println(messageCount + " is the current messagecount.");
+    }
+
+
+    private Optional<Address> getAddress(String name) {
+        View view = channel.view();
+        return view.getMembers().stream().filter(address -> name.equals(address.toString())).findFirst();
+    }
+
+}
+
+
--- a/jgroups/src/main/resources/udp.xml
+++ b/jgroups/src/main/resources/udp.xml
@ -0,0 +1,48 @@
+<config xmlns="urn:org:jgroups"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="urn:org:jgroups http://www.jgroups.org/schema/jgroups.xsd">
+    <UDP
+         mcast_port="${jgroups.udp.mcast_port:45588}"
+         ip_ttl="4"
+         tos="8"
+         ucast_recv_buf_size="5M"
+         ucast_send_buf_size="5M"
+         mcast_recv_buf_size="5M"
+         mcast_send_buf_size="5M"
+         max_bundle_size="64K"
+         enable_diagnostics="true"
+         thread_naming_pattern="cl"
+
+         thread_pool.min_threads="0"
+         thread_pool.max_threads="20"
+         thread_pool.keep_alive_time="30000"/>
+
+    <PING />
+    <MERGE3 max_interval="30000"
+            min_interval="10000"/>
+    <FD_SOCK/>
+    <FD_ALL/>
+    <VERIFY_SUSPECT timeout="1500"  />
+    <BARRIER />
+    <pbcast.NAKACK2 xmit_interval="500"
+                    xmit_table_num_rows="100"
+                    xmit_table_msgs_per_row="2000"
+                    xmit_table_max_compaction_time="30000"
+                    use_mcast_xmit="false"
+                    discard_delivered_msgs="true"/>
+    <UNICAST3 xmit_interval="500"
+              xmit_table_num_rows="100"
+              xmit_table_msgs_per_row="2000"
+              xmit_table_max_compaction_time="60000"
+              conn_expiry_timeout="0"/>
+    <pbcast.STABLE desired_avg_gossip="50000"
+                   max_bytes="4M"/>
+    <pbcast.GMS print_local_addr="true" join_timeout="2000"/>
+    <UFC max_credits="2M"
+         min_threshold="0.4"/>
+    <MFC max_credits="2M"
+         min_threshold="0.4"/>
+    <FRAG2 frag_size="60K"  />
+    <RSVP resend_interval="2000" timeout="10000"/>
+    <pbcast.STATE_TRANSFER />
+</config>
--- a/json/pom.xml
+++ b/json/pom.xml
@ -31,6 +31,11 @@
            <version>${fastjson.version}</version>
        </dependency>

+        <dependency>
+            <groupId>org.json</groupId>
+            <artifactId>json</artifactId>
+            <version>20171018</version>
+        </dependency>
    </dependencies>

    <properties>
--- a/json/src/main/java/com/baeldung/jsonjava/CDLDemo.java
+++ b/json/src/main/java/com/baeldung/jsonjava/CDLDemo.java
@ -0,0 +1,59 @@
+package com.baeldung.jsonjava;
+
+import org.json.CDL;
+import org.json.JSONArray;
+import org.json.JSONTokener;
+
+public class CDLDemo {
+    public static void main(String[] args) {
+        System.out.println("7.1. Producing JSONArray Directly from Comma Delimited Text: ");
+        jsonArrayFromCDT();
+        
+        System.out.println("\n7.2. Producing Comma Delimited Text from JSONArray: ");
+        cDTfromJSONArray();
+        
+        System.out.println("\n7.3.1. Producing JSONArray of JSONObjects Using Comma Delimited Text: ");
+        jaOfJOFromCDT2();
+        
+        System.out.println("\n7.3.2. Producing JSONArray of JSONObjects Using Comma Delimited Text: ");
+        jaOfJOFromCDT2();
+    }
+    
+    public static void jsonArrayFromCDT() {
+        JSONArray ja = CDL.rowToJSONArray(new JSONTokener("England, USA, Canada"));
+        System.out.println(ja);
+    }
+    
+    public static void cDTfromJSONArray() {
+        JSONArray ja = new JSONArray("[\"England\",\"USA\",\"Canada\"]");
+        String cdt = CDL.rowToString(ja);
+        System.out.println(cdt);
+    }
+    
+    public static void jaOfJOFromCDT() {
+        String string = 
+          "name, city, age \n" +
+          "john, chicago, 22 \n" +
+          "gary, florida, 35 \n" +
+          "sal, vegas, 18";
+         
+        JSONArray result = CDL.toJSONArray(string);
+        System.out.println(result.toString());
+    }
+    
+    public static void jaOfJOFromCDT2() {
+        JSONArray ja = new JSONArray();
+        ja.put("name");
+        ja.put("city");
+        ja.put("age");
+         
+        String string = 
+          "john, chicago, 22 \n" +
+          "gary, florida, 35 \n" +
+          "sal, vegas, 18";
+         
+        JSONArray result = CDL.toJSONArray(ja, string);
+        System.out.println(result.toString());
+    }
+    
+}
--- a/json/src/main/java/com/baeldung/jsonjava/CookieDemo.java
+++ b/json/src/main/java/com/baeldung/jsonjava/CookieDemo.java
@ -0,0 +1,30 @@
+package com.baeldung.jsonjava;
+
+import org.json.Cookie;
+import org.json.JSONObject;
+
+public class CookieDemo {
+    public static void main(String[] args) {
+        System.out.println("8.1. Converting a Cookie String into a JSONObject");
+        cookieStringToJSONObject();
+        
+        System.out.println("\n8.2. Converting a JSONObject into Cookie String");
+        jSONObjectToCookieString();
+    }
+    
+    public static void cookieStringToJSONObject() {
+        String cookie = "username=John Doe; expires=Thu, 18 Dec 2013 12:00:00 UTC; path=/";
+        JSONObject cookieJO = Cookie.toJSONObject(cookie);
+        System.out.println(cookieJO);
+    }
+    
+    public static void jSONObjectToCookieString() {
+        JSONObject cookieJO = new JSONObject();
+        cookieJO.put("name", "username");
+        cookieJO.put("value", "John Doe");
+        cookieJO.put("expires", "Thu, 18 Dec 2013 12:00:00 UTC");
+        cookieJO.put("path", "/");
+        String cookie = Cookie.toString(cookieJO);
+        System.out.println(cookie);
+    }
+}
--- a/json/src/main/java/com/baeldung/jsonjava/DemoBean.java
+++ b/json/src/main/java/com/baeldung/jsonjava/DemoBean.java
@ -0,0 +1,26 @@
+package com.baeldung.jsonjava;
+
+public class DemoBean {
+    private int id;
+    private String name;
+    private boolean active;
+    
+    public int getId() {
+        return id;
+    }
+    public void setId(int id) {
+        this.id = id;
+    }
+    public String getName() {
+        return name;
+    }
+    public void setName(String name) {
+        this.name = name;
+    }
+    public boolean isActive() {
+        return active;
+    }
+    public void setActive(boolean active) {
+        this.active = active;
+    }
+}
--- a/json/src/main/java/com/baeldung/jsonjava/HTTPDemo.java
+++ b/json/src/main/java/com/baeldung/jsonjava/HTTPDemo.java
@ -0,0 +1,27 @@
+package com.baeldung.jsonjava;
+
+import org.json.HTTP;
+import org.json.JSONObject;
+
+public class HTTPDemo {
+    public static void main(String[] args) {
+        System.out.println("9.1. Converting JSONObject to HTTP Header: ");
+        jSONObjectToHTTPHeader();
+        
+        System.out.println("\n9.2. Converting HTTP Header String Back to JSONObject: ");
+        hTTPHeaderToJSONObject();
+    }
+    
+    public static void jSONObjectToHTTPHeader() {
+        JSONObject jo = new JSONObject();
+        jo.put("Method", "POST");
+        jo.put("Request-URI", "http://www.example.com/");
+        jo.put("HTTP-Version", "HTTP/1.1");
+        System.out.println(HTTP.toString(jo));
+    }
+    
+    public static void hTTPHeaderToJSONObject() {
+        JSONObject obj = HTTP.toJSONObject("POST \"http://www.example.com/\" HTTP/1.1");
+        System.out.println(obj);
+    }
+}
--- a/json/src/main/java/com/baeldung/jsonjava/JSONArrayDemo.java
+++ b/json/src/main/java/com/baeldung/jsonjava/JSONArrayDemo.java
@ -0,0 +1,52 @@
+package com.baeldung.jsonjava;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.json.JSONArray;
+import org.json.JSONObject;
+
+public class JSONArrayDemo {
+    public static void main(String[] args) {
+        System.out.println("5.1. Creating JSON Array: ");
+        creatingJSONArray();
+        
+        System.out.println("\n5.2. Creating JSON Array from JSON string: ");
+        jsonArrayFromJSONString();
+        
+        System.out.println("\n5.3. Creating JSON Array from Collection Object: ");
+        jsonArrayFromCollectionObj();
+    }
+    
+    public static void creatingJSONArray() {
+        JSONArray ja = new JSONArray();
+        ja.put(Boolean.TRUE);
+        ja.put("lorem ipsum");
+         
+        // We can also put a JSONObject in JSONArray
+        JSONObject jo = new JSONObject();
+        jo.put("name", "jon doe");
+        jo.put("age", "22");
+        jo.put("city", "chicago");
+         
+        ja.put(jo);
+         
+        System.out.println(ja.toString());
+    }
+    
+    public static void jsonArrayFromJSONString() {
+        JSONArray ja = new JSONArray("[true, \"lorem ipsum\", 215]");
+        System.out.println(ja);
+    }
+    
+    public static void jsonArrayFromCollectionObj() {
+        List<String> list = new ArrayList<>();
+        list.add("California");
+        list.add("Texas");
+        list.add("Hawaii");
+        list.add("Alaska");
+         
+        JSONArray ja = new JSONArray(list);
+        System.out.println(ja);
+    }
+}
--- a/json/src/main/java/com/baeldung/jsonjava/JSONObjectDemo.java
+++ b/json/src/main/java/com/baeldung/jsonjava/JSONObjectDemo.java
@ -0,0 +1,59 @@
+package com.baeldung.jsonjava;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.json.JSONObject;
+
+public class JSONObjectDemo {
+    public static void main(String[] args) {
+        System.out.println("4.1. Creating JSONObject: ");
+        jsonFromJSONObject();
+        
+        System.out.println("\n4.2. Creating JSONObject from Map: ");
+        jsonFromMap();
+        
+        System.out.println("\n4.3. Creating JSONObject from JSON string: ");
+        jsonFromJSONString();
+        
+        System.out.println("\n4.4. Creating JSONObject from Java Bean: ");
+        jsonFromDemoBean();
+    }
+    
+    public static void jsonFromJSONObject() {
+        JSONObject jo = new JSONObject();
+        jo.put("name", "jon doe");
+        jo.put("age", "22");
+        jo.put("city", "chicago");
+             
+        System.out.println(jo.toString());
+    }
+    
+    public static void jsonFromMap() {
+        Map<String, String> map = new HashMap<>();
+        map.put("name", "jon doe");
+        map.put("age", "22");
+        map.put("city", "chicago");
+        JSONObject jo = new JSONObject(map);
+         
+        System.out.println(jo.toString());
+    }
+    
+    public static void jsonFromJSONString() {
+        JSONObject jo = new JSONObject(
+          "{\"city\":\"chicago\",\"name\":\"jon doe\",\"age\":\"22\"}"
+        );
+        
+        System.out.println(jo.toString());
+    }
+    
+    public static void jsonFromDemoBean() {
+        DemoBean demo = new DemoBean();
+        demo.setId(1);
+        demo.setName("lorem ipsum");
+        demo.setActive(true);
+         
+        JSONObject jo = new JSONObject(demo);
+        System.out.println(jo);
+    }
+}
--- a/json/src/main/java/com/baeldung/jsonjava/JSONTokenerDemo.java
+++ b/json/src/main/java/com/baeldung/jsonjava/JSONTokenerDemo.java
@ -0,0 +1,13 @@
+package com.baeldung.jsonjava;
+
+import org.json.JSONTokener;
+
+public class JSONTokenerDemo {
+    public static void main(String[] args) {
+        JSONTokener jt = new JSONTokener("Sample String");
+         
+        while(jt.more()) {
+            System.out.println(jt.next());
+        }
+    }
+}
--- a/json/src/test/java/com/baeldung/jsonjava/CDLIntegrationTest.java
+++ b/json/src/test/java/com/baeldung/jsonjava/CDLIntegrationTest.java
@ -0,0 +1,52 @@
+package com.baeldung.jsonjava;
+
+import static org.junit.Assert.assertEquals;
+
+import org.json.CDL;
+import org.json.JSONArray;
+import org.json.JSONTokener;
+import org.junit.Test;
+
+public class CDLIntegrationTest {
+    @Test
+    public void givenCommaDelimitedText_thenConvertToJSONArray() {
+        JSONArray ja = CDL.rowToJSONArray(new JSONTokener("England, USA, Canada"));
+        assertEquals("[\"England\",\"USA\",\"Canada\"]", ja.toString());
+    }
+
+    @Test
+    public void givenJSONArray_thenConvertToCommaDelimitedText() {
+        JSONArray ja = new JSONArray("[\"England\",\"USA\",\"Canada\"]");
+        String cdt = CDL.rowToString(ja);
+        assertEquals("England,USA,Canada", cdt.toString().trim());
+    }
+
+    @Test
+    public void givenCommaDelimitedText_thenGetJSONArrayOfJSONObjects() {
+        String string = 
+          "name, city, age \n" +
+          "john, chicago, 22 \n" +
+          "gary, florida, 35 \n" +
+          "sal, vegas, 18";
+         
+        JSONArray result = CDL.toJSONArray(string);
+        assertEquals("[{\"name\":\"john\",\"city\":\"chicago\",\"age\":\"22\"},{\"name\":\"gary\",\"city\":\"florida\",\"age\":\"35\"},{\"name\":\"sal\",\"city\":\"vegas\",\"age\":\"18\"}]", result.toString());
+    }
+
+    @Test
+    public void givenCommaDelimitedText_thenGetJSONArrayOfJSONObjects2() {
+        JSONArray ja = new JSONArray();
+        ja.put("name");
+        ja.put("city");
+        ja.put("age");
+         
+        String string = 
+          "john, chicago, 22 \n" +
+          "gary, florida, 35 \n" +
+          "sal, vegas, 18";
+         
+        JSONArray result = CDL.toJSONArray(ja, string);
+        assertEquals("[{\"name\":\"john\",\"city\":\"chicago\",\"age\":\"22\"},{\"name\":\"gary\",\"city\":\"florida\",\"age\":\"35\"},{\"name\":\"sal\",\"city\":\"vegas\",\"age\":\"18\"}]", result.toString());
+    }
+    
+}
--- a/json/src/test/java/com/baeldung/jsonjava/CookieIntegrationTest.java
+++ b/json/src/test/java/com/baeldung/jsonjava/CookieIntegrationTest.java
@ -0,0 +1,29 @@
+package com.baeldung.jsonjava;
+
+import static org.junit.Assert.assertEquals;
+
+import org.json.Cookie;
+import org.json.JSONObject;
+import org.junit.Test;
+
+public class CookieIntegrationTest {
+    @Test
+    public void givenCookieString_thenConvertToJSONObject() {
+        String cookie = "username=John Doe; expires=Thu, 18 Dec 2013 12:00:00 UTC; path=/";
+        JSONObject cookieJO = Cookie.toJSONObject(cookie);
+
+        assertEquals("{\"path\":\"/\",\"expires\":\"Thu, 18 Dec 2013 12:00:00 UTC\",\"name\":\"username\",\"value\":\"John Doe\"}", cookieJO.toString());
+    }
+    
+    @Test
+    public void givenJSONObject_thenConvertToCookieString() {
+        JSONObject cookieJO = new JSONObject();
+        cookieJO.put("name", "username");
+        cookieJO.put("value", "John Doe");
+        cookieJO.put("expires", "Thu, 18 Dec 2013 12:00:00 UTC");
+        cookieJO.put("path", "/");
+        String cookie = Cookie.toString(cookieJO);
+
+        assertEquals("username=John Doe;expires=Thu, 18 Dec 2013 12:00:00 UTC;path=/", cookie.toString());
+    }
+}
--- a/json/src/test/java/com/baeldung/jsonjava/HTTPIntegrationTest.java
+++ b/json/src/test/java/com/baeldung/jsonjava/HTTPIntegrationTest.java
@ -0,0 +1,25 @@
+package com.baeldung.jsonjava;
+
+import static org.junit.Assert.assertEquals;
+import org.json.HTTP;
+import org.json.JSONObject;
+import org.junit.Test;
+
+public class HTTPIntegrationTest {
+    @Test
+    public void givenJSONObject_thenConvertToHTTPHeader() {
+        JSONObject jo = new JSONObject();
+        jo.put("Method", "POST");
+        jo.put("Request-URI", "http://www.example.com/");
+        jo.put("HTTP-Version", "HTTP/1.1");
+        
+        assertEquals("POST \"http://www.example.com/\" HTTP/1.1"+HTTP.CRLF+HTTP.CRLF, HTTP.toString(jo));
+    }
+
+    @Test
+    public void givenHTTPHeader_thenConvertToJSONObject() {
+        JSONObject obj = HTTP.toJSONObject("POST \"http://www.example.com/\" HTTP/1.1");
+        
+        assertEquals("{\"Request-URI\":\"http://www.example.com/\",\"Method\":\"POST\",\"HTTP-Version\":\"HTTP/1.1\"}", obj.toString());
+    }
+}
--- a/json/src/test/java/com/baeldung/jsonjava/JSONArrayIntegrationTest.java
+++ b/json/src/test/java/com/baeldung/jsonjava/JSONArrayIntegrationTest.java
@ -0,0 +1,47 @@
+package com.baeldung.jsonjava;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.json.JSONArray;
+import org.json.JSONObject;
+import org.junit.Test;
+
+public class JSONArrayIntegrationTest {
+    @Test
+    public void givenJSONJava_thenCreateNewJSONArrayFromScratch() {
+        JSONArray ja = new JSONArray();
+        ja.put(Boolean.TRUE);
+        ja.put("lorem ipsum");
+         
+        // We can also put a JSONObject in JSONArray
+        JSONObject jo = new JSONObject();
+        jo.put("name", "jon doe");
+        jo.put("age", "22");
+        jo.put("city", "chicago");
+         
+        ja.put(jo);
+         
+        assertEquals("[true,\"lorem ipsum\",{\"city\":\"chicago\",\"name\":\"jon doe\",\"age\":\"22\"}]", ja.toString());
+    }
+    
+    @Test
+    public void givenJsonString_thenCreateNewJSONArray() {
+        JSONArray ja = new JSONArray("[true, \"lorem ipsum\", 215]");
+        assertEquals("[true,\"lorem ipsum\",215]", ja.toString());
+    }
+
+    @Test
+    public void givenListObject_thenConvertItToJSONArray() {
+        List<String> list = new ArrayList<>();
+        list.add("California");
+        list.add("Texas");
+        list.add("Hawaii");
+        list.add("Alaska");
+         
+        JSONArray ja = new JSONArray(list);
+        assertEquals("[\"California\",\"Texas\",\"Hawaii\",\"Alaska\"]", ja.toString());
+    }
+}
--- a/json/src/test/java/com/baeldung/jsonjava/JSONObjectIntegrationTest.java
+++ b/json/src/test/java/com/baeldung/jsonjava/JSONObjectIntegrationTest.java
@ -0,0 +1,53 @@
+package com.baeldung.jsonjava;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.json.JSONObject;
+import org.junit.Test;
+
+public class JSONObjectIntegrationTest {
+    @Test
+    public void givenJSONJava_thenCreateNewJSONObject() {
+        JSONObject jo = new JSONObject();
+        jo.put("name", "jon doe");
+        jo.put("age", "22");
+        jo.put("city", "chicago");
+             
+        assertEquals("{\"city\":\"chicago\",\"name\":\"jon doe\",\"age\":\"22\"}", jo.toString());
+        
+    }
+
+    @Test
+    public void givenMapObject_thenCreateJSONObject() {
+        Map<String, String> map = new HashMap<>();
+        map.put("name", "jon doe");
+        map.put("age", "22");
+        map.put("city", "chicago");
+        JSONObject jo = new JSONObject(map);
+         
+        assertEquals("{\"name\":\"jon doe\",\"city\":\"chicago\",\"age\":\"22\"}", jo.toString());
+    }
+
+    @Test
+    public void givenJsonString_thenCreateJSONObject() {
+        JSONObject jo = new JSONObject(
+          "{\"city\":\"chicago\",\"name\":\"jon doe\",\"age\":\"22\"}"
+        );
+        
+        assertEquals("{\"city\":\"chicago\",\"name\":\"jon doe\",\"age\":\"22\"}", jo.toString());
+    }
+
+    @Test
+    public void givenDemoBean_thenCreateJSONObject() {
+        DemoBean demo = new DemoBean();
+        demo.setId(1);
+        demo.setName("lorem ipsum");
+        demo.setActive(true);
+         
+        JSONObject jo = new JSONObject(demo);
+        assertEquals("{\"name\":\"lorem ipsum\",\"active\":true,\"id\":1}", jo.toString());
+    }
+}
--- a/json/src/test/java/com/baeldung/jsonjava/JSONTokenerIntegrationTest.java
+++ b/json/src/test/java/com/baeldung/jsonjava/JSONTokenerIntegrationTest.java
@ -0,0 +1,21 @@
+package com.baeldung.jsonjava;
+
+import static org.junit.Assert.assertEquals;
+
+import org.json.JSONTokener;
+import org.junit.Test;
+
+public class JSONTokenerIntegrationTest {
+    @Test
+    public void givenString_convertItToJSONTokens() {
+        String str = "Sample String";
+        JSONTokener jt = new JSONTokener(str);
+        
+        char[] expectedTokens = str.toCharArray();
+        int index = 0;
+        
+        while(jt.more()) {
+            assertEquals(expectedTokens[index++], jt.next());
+        }
+    }
+}
--- a/libraries/README.md
+++ b/libraries/README.md
@ -59,6 +59,7 @@
 - [Intro to JDO Queries 2/2](http://www.baeldung.com/jdo-queries)
 - [Guide to google-http-client](http://www.baeldung.com/google-http-client)
 - [Interact with Google Sheets from Java](http://www.baeldung.com/google-sheets-java-client)
+- [Programatically Create, Configure, and Run a Tomcat Server] (http://www.baeldung.com/tomcat-programmatic-setup)



--- a/libraries/pom.xml
+++ b/libraries/pom.xml
@ -116,6 +116,12 @@
        </plugins>
    </build>
    <dependencies>
+    	<!-- https://mvnrepository.com/artifact/org.asynchttpclient/async-http-client -->
+        <dependency>
+            <groupId>org.asynchttpclient</groupId>
+            <artifactId>async-http-client</artifactId>
+            <version>${async.http.client.version}</version>
+        </dependency>
        <!-- https://mvnrepository.com/artifact/org.beykery/neuroph/2.92 -->
        <dependency>
            <groupId>org.beykery</groupId>
@ -710,6 +716,18 @@
            <classifier>test</classifier>
            <scope>test</scope>
        </dependency>
+
+        <!-- tomcat -->
+        <dependency>
+            <groupId>org.apache.tomcat</groupId>
+            <artifactId>tomcat-catalina</artifactId>
+            <version>${tomcat.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.milyn</groupId>
+            <artifactId>milyn-smooks-all</artifactId>
+            <version>${smooks.version}</version>
+        </dependency>
    </dependencies>
    <repositories>
        <repository>
@ -761,7 +779,7 @@
        <serenity.jira.version>1.1.3-rc.5</serenity.jira.version>
        <serenity.plugin.version>1.4.0</serenity.plugin.version>
        <jUnitParams.version>1.1.0</jUnitParams.version>
-        <netty.version>4.1.15.Final</netty.version>
+        <netty.version>4.1.20.Final</netty.version>
        <commons.collections.version>4.1</commons.collections.version>
        <junit.version>4.12</junit.version>
        <java-lsh.version>0.10</java-lsh.version>
@ -789,6 +807,9 @@
        <google-api.version>1.23.0</google-api.version>
        <google-sheets.version>v4-rev493-1.21.0</google-sheets.version>
        <kafka.version>1.0.0</kafka.version>
+        <smooks.version>1.7.0</smooks.version>
        <docker.version>3.0.14</docker.version>
+        <tomcat.version>8.5.24</tomcat.version>
+        <async.http.client.version>2.2.0</async.http.client.version>
    </properties>
 </project>
--- a/libraries/src/main/java/com/baeldung/smooks/converter/OrderConverter.java
+++ b/libraries/src/main/java/com/baeldung/smooks/converter/OrderConverter.java
@ -0,0 +1,45 @@
+package com.baeldung.smooks.converter;
+
+import com.baeldung.smooks.model.Order;
+import org.milyn.Smooks;
+import org.milyn.payload.JavaResult;
+import org.milyn.payload.StringResult;
+import org.xml.sax.SAXException;
+
+import javax.xml.transform.stream.StreamSource;
+import java.io.IOException;
+
+public class OrderConverter {
+
+    public Order convertOrderXMLToOrderObject(String path) throws IOException, SAXException {
+        Smooks smooks = new Smooks(OrderConverter.class.getResourceAsStream("/smooks/smooks-mapping.xml"));
+        try {
+            JavaResult javaResult = new JavaResult();
+            smooks.filterSource(new StreamSource(OrderConverter.class.getResourceAsStream(path)), javaResult);
+            return (Order) javaResult.getBean("order");
+        } finally {
+            smooks.close();
+        }
+    }
+    
+
+    public String convertOrderXMLtoEDIFACT(String path) throws IOException, SAXException {
+        return convertDocumentWithTempalte(path, "/smooks/smooks-transform-edi.xml");
+    }
+
+    public String convertOrderXMLtoEmailMessage(String path) throws IOException, SAXException {
+        return convertDocumentWithTempalte(path, "/smooks/smooks-transform-email.xml");
+    }
+
+    private String convertDocumentWithTempalte(String path, String config) throws IOException, SAXException {
+        Smooks smooks = new Smooks(config);
+
+        try {
+            StringResult stringResult = new StringResult();
+            smooks.filterSource(new StreamSource(OrderConverter.class.getResourceAsStream(path)), stringResult);
+            return stringResult.toString();
+        } finally {
+            smooks.close();
+        }
+    }
+}
--- a/libraries/src/main/java/com/baeldung/smooks/converter/OrderValidator.java
+++ b/libraries/src/main/java/com/baeldung/smooks/converter/OrderValidator.java
@ -0,0 +1,27 @@
+package com.baeldung.smooks.converter;
+
+import org.milyn.Smooks;
+import org.milyn.payload.JavaResult;
+import org.milyn.payload.StringResult;
+import org.milyn.validation.ValidationResult;
+import org.xml.sax.SAXException;
+
+import javax.xml.transform.stream.StreamSource;
+import java.io.IOException;
+
+public class OrderValidator {
+
+    public ValidationResult validate(String path) throws IOException, SAXException {
+        Smooks smooks = new Smooks(OrderValidator.class.getResourceAsStream("/smooks/smooks-validation.xml"));
+
+        try {
+            StringResult xmlResult = new StringResult();
+            JavaResult javaResult = new JavaResult();
+            ValidationResult validationResult = new ValidationResult();
+            smooks.filterSource(new StreamSource(OrderValidator.class.getResourceAsStream(path)), xmlResult, javaResult, validationResult);
+            return validationResult;
+        } finally {
+            smooks.close();
+        }
+    }
+}
--- a/libraries/src/main/java/com/baeldung/smooks/model/Item.java
+++ b/libraries/src/main/java/com/baeldung/smooks/model/Item.java
@ -0,0 +1,71 @@
+package com.baeldung.smooks.model;
+
+public class Item {
+
+    public Item() {
+    }
+
+    public Item(String code, Double price, Integer quantity) {
+        this.code = code;
+        this.price = price;
+        this.quantity = quantity;
+    }
+
+    private String code;
+    private Double price;
+    private Integer quantity;
+
+
+    public String getCode() {
+        return code;
+    }
+
+    public void setCode(String code) {
+        this.code = code;
+    }
+
+    public Double getPrice() {
+        return price;
+    }
+
+    public void setPrice(Double price) {
+        this.price = price;
+    }
+
+    public Integer getQuantity() {
+        return quantity;
+    }
+
+    public void setQuantity(Integer quantity) {
+        this.quantity = quantity;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Item item = (Item) o;
+
+        if (code != null ? !code.equals(item.code) : item.code != null) return false;
+        if (price != null ? !price.equals(item.price) : item.price != null) return false;
+        return quantity != null ? quantity.equals(item.quantity) : item.quantity == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = code != null ? code.hashCode() : 0;
+        result = 31 * result + (price != null ? price.hashCode() : 0);
+        result = 31 * result + (quantity != null ? quantity.hashCode() : 0);
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "Item{" +
+                "code='" + code + '\'' +
+                ", price=" + price +
+                ", quantity=" + quantity +
+                '}';
+    }
+}
--- a/libraries/src/main/java/com/baeldung/smooks/model/Order.java
+++ b/libraries/src/main/java/com/baeldung/smooks/model/Order.java
@ -0,0 +1,52 @@
+package com.baeldung.smooks.model;
+
+import java.util.Date;
+import java.util.List;
+
+public class Order {
+    private Date creationDate;
+    private Long number;
+    private Status status;
+    private Supplier supplier;
+    private List<Item> items;
+
+    public Date getCreationDate() {
+        return creationDate;
+    }
+
+    public void setCreationDate(Date creationDate) {
+        this.creationDate = creationDate;
+    }
+
+    public Long getNumber() {
+        return number;
+    }
+
+    public void setNumber(Long number) {
+        this.number = number;
+    }
+
+    public Status getStatus() {
+        return status;
+    }
+
+    public void setStatus(Status status) {
+        this.status = status;
+    }
+
+    public Supplier getSupplier() {
+        return supplier;
+    }
+
+    public void setSupplier(Supplier supplier) {
+        this.supplier = supplier;
+    }
+
+    public List<Item> getItems() {
+        return items;
+    }
+
+    public void setItems(List<Item> items) {
+        this.items = items;
+    }
+}
--- a/libraries/src/main/java/com/baeldung/smooks/model/Status.java
+++ b/libraries/src/main/java/com/baeldung/smooks/model/Status.java
@ -0,0 +1,5 @@
+package com.baeldung.smooks.model;
+
+public enum Status {
+    NEW, IN_PROGRESS, FINISHED
+}
--- a/libraries/src/main/java/com/baeldung/smooks/model/Supplier.java
+++ b/libraries/src/main/java/com/baeldung/smooks/model/Supplier.java
@ -0,0 +1,49 @@
+package com.baeldung.smooks.model;
+
+public class Supplier {
+
+    private String name;
+    private String phoneNumber;
+
+    public Supplier() {
+    }
+
+    public Supplier(String name, String phoneNumber) {
+        this.name = name;
+        this.phoneNumber = phoneNumber;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getPhoneNumber() {
+        return phoneNumber;
+    }
+
+    public void setPhoneNumber(String phoneNumber) {
+        this.phoneNumber = phoneNumber;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Supplier supplier = (Supplier) o;
+
+        if (name != null ? !name.equals(supplier.name) : supplier.name != null) return false;
+        return phoneNumber != null ? phoneNumber.equals(supplier.phoneNumber) : supplier.phoneNumber == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = name != null ? name.hashCode() : 0;
+        result = 31 * result + (phoneNumber != null ? phoneNumber.hashCode() : 0);
+        return result;
+    }
+}
--- a/libraries/src/main/java/com/baeldung/tomcat/MyFilter.java
+++ b/libraries/src/main/java/com/baeldung/tomcat/MyFilter.java
@ -0,0 +1,31 @@
+package com.baeldung.tomcat;
+
+import javax.servlet.*;
+import javax.servlet.annotation.WebFilter;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+/**
+ * Created by adi on 1/14/18.
+ */
+@WebFilter(urlPatterns = "/my-servlet/*")
+public class MyFilter implements Filter {
+
+    @Override
+    public void init(FilterConfig filterConfig) {
+
+    }
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+        System.out.println("Filtering stuff...");
+        HttpServletResponse httpResponse = (HttpServletResponse) response;
+        httpResponse.addHeader("myHeader", "myHeaderValue");
+        chain.doFilter(request, httpResponse);
+    }
+
+    @Override
+    public void destroy() {
+
+    }
+}
--- a/libraries/src/main/java/com/baeldung/tomcat/MyServlet.java
+++ b/libraries/src/main/java/com/baeldung/tomcat/MyServlet.java
@ -0,0 +1,25 @@
+package com.baeldung.tomcat;
+
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+/**
+ * Created by adi on 1/10/18.
+ */
+@WebServlet(
+  name = "com.baeldung.tomcat.programmatic.MyServlet",
+  urlPatterns = {"/my-servlet"}
+)
+public class MyServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+        resp.setStatus(HttpServletResponse.SC_OK);
+        resp.getWriter().write("test");
+        resp.getWriter().flush();
+        resp.getWriter().close();
+    }
+}
--- a/libraries/src/main/java/com/baeldung/tomcat/ProgrammaticTomcat.java
+++ b/libraries/src/main/java/com/baeldung/tomcat/ProgrammaticTomcat.java
@ -0,0 +1,63 @@
+package com.baeldung.tomcat;
+
+import org.apache.catalina.Context;
+import org.apache.catalina.LifecycleException;
+import org.apache.catalina.startup.Tomcat;
+import org.apache.tomcat.util.descriptor.web.FilterDef;
+import org.apache.tomcat.util.descriptor.web.FilterMap;
+
+import java.io.File;
+
+/**
+ * Created by adi on 1/10/18.
+ */
+public class ProgrammaticTomcat {
+
+    private Tomcat tomcat = null;
+
+    //uncomment for live test
+    //    public static void main(String[] args) throws LifecycleException, ServletException, URISyntaxException, IOException {
+    //        startTomcat();
+    //    }
+
+    public void startTomcat() throws LifecycleException {
+        tomcat = new Tomcat();
+        tomcat.setPort(8080);
+        tomcat.setHostname("localhost");
+        String appBase = ".";
+        tomcat
+          .getHost()
+          .setAppBase(appBase);
+
+        File docBase = new File(System.getProperty("java.io.tmpdir"));
+        Context context = tomcat.addContext("", docBase.getAbsolutePath());
+
+        //add a servlet
+        Class servletClass = MyServlet.class;
+        Tomcat.addServlet(context, servletClass.getSimpleName(), servletClass.getName());
+        context.addServletMappingDecoded("/my-servlet/*", servletClass.getSimpleName());
+
+        //add a filter and filterMapping
+        Class filterClass = MyFilter.class;
+        FilterDef myFilterDef = new FilterDef();
+        myFilterDef.setFilterClass(filterClass.getName());
+        myFilterDef.setFilterName(filterClass.getSimpleName());
+        context.addFilterDef(myFilterDef);
+
+        FilterMap myFilterMap = new FilterMap();
+        myFilterMap.setFilterName(filterClass.getSimpleName());
+        myFilterMap.addURLPattern("/my-servlet/*");
+        context.addFilterMap(myFilterMap);
+
+        tomcat.start();
+        //uncomment for live test
+        //        tomcat
+        //          .getServer()
+        //          .await();
+    }
+
+    public void stopTomcat() throws LifecycleException {
+        tomcat.stop();
+        tomcat.destroy();
+    }
+}
--- a/libraries/src/main/resources/smooks/email.ftl
+++ b/libraries/src/main/resources/smooks/email.ftl
@ -0,0 +1,8 @@
+<#setting locale="en_US">
+Hi,
+Order number #${order.number} created on ${order.creationDate?string["yyyy-MM-dd"]} is currently in ${order.status} status.
+Consider contact supplier "${supplier.name}"  with phone number: "${supplier.phoneNumber}".
+Order items:
+<#list items as item>
+${item.quantity}  X ${item.code} (total price ${item.price * item.quantity})
+</#list>
--- a/libraries/src/main/resources/smooks/item-rules.csv
+++ b/libraries/src/main/resources/smooks/item-rules.csv
@ -0,0 +1 @@
+"max_total","item.quantity * item.price < 300.00"
--- a/libraries/src/main/resources/smooks/order.ftl
+++ b/libraries/src/main/resources/smooks/order.ftl
@ -0,0 +1,7 @@
+<#setting locale="en_US">
+UNA:+.? '
+UNH+${order.number}+${order.status}+${order.creationDate?string["yyyy-MM-dd"]}'
+CTA+${supplier.name}+${supplier.phoneNumber}'
+<#list items as item>
+LIN+${item.quantity}+${item.code}+${item.price}'
+</#list>
--- a/libraries/src/main/resources/smooks/order.json
+++ b/libraries/src/main/resources/smooks/order.json
@ -0,0 +1,21 @@
+{
+  "creationDate":"2018-01-14",
+  "orderNumber":771,
+  "orderStatus":"IN_PROGRESS",
+  "supplier":{
+    "name":"CompanyX",
+    "phone":"1234567"
+  },
+  "orderItems":[
+    {
+      "quantity":1,
+      "code":"PX1234",
+      "price":9.99
+    },
+    {
+      "quantity":2,
+      "code":"RX1990",
+      "price":120.32
+    }
+  ]
+}
--- a/libraries/src/main/resources/smooks/order.xml
+++ b/libraries/src/main/resources/smooks/order.xml
@ -0,0 +1,20 @@
+<order creation-date="2018-01-14">
+    <order-number>771</order-number>
+    <order-status>IN_PROGRESS</order-status>
+    <supplier>
+        <name>CompanyX</name>
+        <phone>1234567</phone>
+    </supplier>
+    <order-items>
+        <item>
+            <quantity>1</quantity>
+            <code>PX1234</code>
+            <price>9.99</price>
+        </item>
+        <item>
+            <quantity>2</quantity>
+            <code>RX990</code>
+            <price>120.32</price>
+        </item>
+    </order-items>
+</order>
--- a/libraries/src/main/resources/smooks/smooks-mapping.xml
+++ b/libraries/src/main/resources/smooks/smooks-mapping.xml
@ -0,0 +1,29 @@
+<?xml version="1.0"?>
+<smooks-resource-list xmlns="http://www.milyn.org/xsd/smooks-1.1.xsd"
+                      xmlns:jb="http://www.milyn.org/xsd/smooks/javabean-1.2.xsd">
+
+    <jb:bean beanId="order" class="com.baeldung.smooks.model.Order" createOnElement="order">
+        <jb:value property="number" data="order/order-number" />
+        <jb:value property="status" data="order/order-status" />
+        <jb:value property="creationDate" data="order/@creation-date"  decoder="Date">
+            <jb:decodeParam name="format">yyyy-MM-dd</jb:decodeParam>
+        </jb:value>
+        <jb:wiring property="supplier" beanIdRef="supplier" />
+        <jb:wiring property="items" beanIdRef="items" />
+    </jb:bean>
+
+    <jb:bean beanId="supplier" class="com.baeldung.smooks.model.Supplier" createOnElement="supplier">
+        <jb:value property="name" data="name" />
+        <jb:value property="phoneNumber" data="phone" />
+    </jb:bean>
+
+    <jb:bean beanId="items" class="java.util.ArrayList" createOnElement="order">
+        <jb:wiring beanIdRef="item" />
+    </jb:bean>
+    <jb:bean beanId="item" class="com.baeldung.smooks.model.Item" createOnElement="item">
+        <jb:value property="code"  data="item/code" />
+        <jb:value property="price" decoder="Double" data="item/price" />
+        <jb:value property="quantity" decoder="Integer" data="item/quantity" />
+    </jb:bean>
+
+</smooks-resource-list>
--- a/Show More
+++ b/Show More
				`@ -0,0 +1 @@`
				`"max_total","item.quantity * item.price < 300.00"`