Merge branch 'master' into master

algorithms/src/main/java/com/baeldung/algorithms/automata/FiniteStateMachine.java

@@ -1,4 +1,4 @@
-package com.baeldung.automata;
+package com.baeldung.algorithms.automata;
 
 /**
  * Finite state machine.

algorithms/src/main/java/com/baeldung/algorithms/automata/RtFiniteStateMachine.java

@@ -1,4 +1,4 @@
-package com.baeldung.automata;
+package com.baeldung.algorithms.automata;
 
 /**
  * Default implementation of a finite state machine.

algorithms/src/main/java/com/baeldung/algorithms/automata/RtState.java

@@ -1,4 +1,4 @@
-package com.baeldung.automata;
+package com.baeldung.algorithms.automata;
 
 import java.util.ArrayList;
 import java.util.List;

algorithms/src/main/java/com/baeldung/algorithms/automata/RtTransition.java

@@ -1,4 +1,4 @@
-package com.baeldung.automata;
+package com.baeldung.algorithms.automata;
 
 
 /**

algorithms/src/main/java/com/baeldung/algorithms/automata/State.java

@@ -1,4 +1,4 @@
-package com.baeldung.automata;
+package com.baeldung.algorithms.automata;
 
 /**
  * State. Part of a finite state machine.

algorithms/src/main/java/com/baeldung/algorithms/automata/Transition.java

@@ -1,4 +1,4 @@
-package com.baeldung.automata;
+package com.baeldung.algorithms.automata;
 
 /**
  * Transition in a finite State machine.

algorithms/src/main/java/com/baeldung/algorithms/hillclimbing/HillClimbing.java

@@ -5,7 +5,6 @@ import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Stack;
-import java.util.stream.Collectors;
 
 public class HillClimbing {
     public static void main(String[] args) {
@@ -22,7 +21,7 @@ public class HillClimbing {
         }
     }
 
-    public static void printEachStep(State state) {
+    private static void printEachStep(State state) {
         List<Stack<String>> stackList = state.getState();
         System.out.println("----------------");
         stackList.forEach(stack -> {
@@ -33,8 +32,8 @@ public class HillClimbing {
         });
     }
 
-    public Stack<String> getStackWithValues(String[] blocks) {
-        Stack<String> stack = new Stack<String>();
+    private Stack<String> getStackWithValues(String[] blocks) {
+        Stack<String> stack = new Stack<>();
         for (String block : blocks)
             stack.push(block);
         return stack;
@@ -42,14 +41,9 @@ public class HillClimbing {
 
     /**
      * This method prepares path from init state to goal state
-     *
-     * @param initStateStack
-     * @param goalStateStack
-     * @return
-     * @throws Exception
      */
     public List<State> getRouteWithHillClimbing(Stack<String> initStateStack, Stack<String> goalStateStack) throws Exception {
-        List<Stack<String>> initStateStackList = new ArrayList<Stack<String>>();
+        List<Stack<String>> initStateStackList = new ArrayList<>();
         initStateStackList.add(initStateStack);
         int initStateHeuristics = getHeuristicsValue(initStateStackList, goalStateStack);
         State initState = new State(initStateStackList, initStateHeuristics);
@@ -71,57 +65,51 @@ public class HillClimbing {
             }
         }
 
-        if (noStateFound)
-            throw new Exception("No path found");
         return resultPath;
     }
 
     /**
      * This method finds new state from current state based on goal and
      * heuristics
-     *
-     * @param currentState
-     * @param goalStateStack
-     * @return a next state
      */
     public State findNextState(State currentState, Stack<String> goalStateStack) {
         List<Stack<String>> listOfStacks = currentState.getState();
         int currentStateHeuristics = currentState.getHeuristics();
 
-        Optional<State> newState = listOfStacks.stream()
+        return listOfStacks.stream()
             .map(stack -> {
-                State tempState = null;
-                List<Stack<String>> tempStackList = new ArrayList<Stack<String>>(listOfStacks);
-                String block = stack.pop();
-                if (stack.size() == 0)
-                    tempStackList.remove(stack);
-                tempState = pushElementToNewStack(tempStackList, block, currentStateHeuristics, goalStateStack);
-                if (tempState == null) {
-                    tempState = pushElementToExistingStacks(stack, tempStackList, block, currentStateHeuristics, goalStateStack);
-                }
-                if (tempState == null)
-                    stack.push(block);
-                return tempState;
+                return applyOperationsOnState(listOfStacks, stack, currentStateHeuristics, goalStateStack);
             })
             .filter(Objects::nonNull)
-            .findFirst();
-
-        return newState.orElse(null);
+            .findFirst()
+          .orElse(null);
     }
 
+    /**
+     * This method applies operations on the current state to get a new state
+     */
+    public State applyOperationsOnState(List<Stack<String>> listOfStacks, Stack<String> stack, int currentStateHeuristics, Stack<String> goalStateStack) {
+        State tempState;
+        List<Stack<String>> tempStackList = new ArrayList<>(listOfStacks);
+        String block = stack.pop();
+        if (stack.size() == 0)
+            tempStackList.remove(stack);
+        tempState = pushElementToNewStack(tempStackList, block, currentStateHeuristics, goalStateStack);
+        if (tempState == null) {
+            tempState = pushElementToExistingStacks(stack, tempStackList, block, currentStateHeuristics, goalStateStack);
+        }
+        if (tempState == null)
+            stack.push(block);
+        return tempState;
+    }
+    
     /**
      * Operation to be applied on a state in order to find new states. This
      * operation pushes an element into a new stack
-     *
-     * @param currentStackList
-     * @param block
-     * @param currentStateHeuristics
-     * @param goalStateStack
-     * @return a new state
      */
     private State pushElementToNewStack(List<Stack<String>> currentStackList, String block, int currentStateHeuristics, Stack<String> goalStateStack) {
         State newState = null;
-        Stack<String> newStack = new Stack<String>();
+        Stack<String> newStack = new Stack<>();
         newStack.push(block);
 
         currentStackList.add(newStack);
@@ -138,62 +126,64 @@ public class HillClimbing {
      * Operation to be applied on a state in order to find new states. This
      * operation pushes an element into one of the other stacks to explore new
      * states
-     *
-     * @param stack
-     * @param currentStackList
-     * @param block
-     * @param currentStateHeuristics
-     * @param goalStateStack
-     * @return a new state
      */
     private State pushElementToExistingStacks(Stack currentStack, List<Stack<String>> currentStackList, String block, int currentStateHeuristics, Stack<String> goalStateStack) {
 
         Optional<State> newState = currentStackList.stream()
             .filter(stack -> stack != currentStack)
             .map(stack -> {
-                stack.push(block);
-                int newStateHeuristics = getHeuristicsValue(currentStackList, goalStateStack);
-                if (newStateHeuristics > currentStateHeuristics) {
-                    return new State(currentStackList, newStateHeuristics);
-                }
-                stack.pop();
-                return null;
+                return pushElementToStack(stack, block, currentStackList, currentStateHeuristics, goalStateStack);
             })
             .filter(Objects::nonNull)
             .findFirst();
 
         return newState.orElse(null);
     }
+    
+    /**
+     * This method pushes a block to the stack and returns new state if its closer to goal
+     */
+    private State pushElementToStack(Stack stack, String block, List<Stack<String>> currentStackList, int currentStateHeuristics, Stack<String> goalStateStack) {
+        stack.push(block);
+        int newStateHeuristics = getHeuristicsValue(currentStackList, goalStateStack);
+        if (newStateHeuristics > currentStateHeuristics) {
+            return new State(currentStackList, newStateHeuristics);
+        }
+        stack.pop();
+        return null;
+    }
 
     /**
      * This method returns heuristics value for given state with respect to goal
      * state
-     *
-     * @param currentState
-     * @param goalStateStack
-     * @return
      */
     public int getHeuristicsValue(List<Stack<String>> currentState, Stack<String> goalStateStack) {
-
-        Integer heuristicValue = 0;
+        Integer heuristicValue;
         heuristicValue = currentState.stream()
             .mapToInt(stack -> {
-                int stackHeuristics = 0;
-                boolean isPositioneCorrect = true;
-                int goalStartIndex = 0;
-                for (String currentBlock : stack) {
-                    if (isPositioneCorrect && currentBlock.equals(goalStateStack.get(goalStartIndex))) {
-                        stackHeuristics += goalStartIndex;
-                    } else {
-                        stackHeuristics -= goalStartIndex;
-                        isPositioneCorrect = false;
-                    }
-                    goalStartIndex++;
-                }
-                return stackHeuristics;
+                return getHeuristicsValueForStack(stack, currentState, goalStateStack);
             })
             .sum();
         return heuristicValue;
     }
+    
+    /**
+     * This method returns heuristics value for a particular stack
+     */
+    public int getHeuristicsValueForStack(Stack<String> stack, List<Stack<String>> currentState, Stack<String> goalStateStack) {
+        int stackHeuristics = 0;
+        boolean isPositioneCorrect = true;
+        int goalStartIndex = 0;
+        for (String currentBlock : stack) {
+            if (isPositioneCorrect && currentBlock.equals(goalStateStack.get(goalStartIndex))) {
+                stackHeuristics += goalStartIndex;
+            } else {
+                stackHeuristics -= goalStartIndex;
+                isPositioneCorrect = false;
+            }
+            goalStartIndex++;
+        }
+        return stackHeuristics;
+    }
 
 }

algorithms/src/main/java/com/baeldung/algorithms/hillclimbing/State.java

@@ -5,26 +5,23 @@ import java.util.List;
 import java.util.Stack;
 
 public class State {
-    List<Stack<String>> state;
-    int heuristics;
-
-    public State() {
-    }
+    private List<Stack<String>> state;
+    private int heuristics;
 
     public State(List<Stack<String>> state) {
         this.state = state;
     }
 
-    public State(List<Stack<String>> state, int heuristics) {
+    State(List<Stack<String>> state, int heuristics) {
         this.state = state;
         this.heuristics = heuristics;
     }
 
-    public State(State state) {
+    State(State state) {
         if (state != null) {
-            this.state = new ArrayList<Stack<String>>();
+            this.state = new ArrayList<>();
             for (Stack s : state.getState()) {
-                Stack s1 = new Stack();
+                Stack s1;
                 s1 = (Stack) s.clone();
                 this.state.add(s1);
             }
@@ -36,10 +33,6 @@ public class State {
         return state;
     }
 
-    public void setState(List<Stack<String>> state) {
-        this.state = state;
-    }
-
     public int getHeuristics() {
         return heuristics;
     }

algorithms/src/main/java/com/baeldung/algorithms/mcts/montecarlo/MonteCarloTreeSearch.java

@@ -0,0 +1,109 @@
+package com.baeldung.algorithms.mcts.montecarlo;
+
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.tictactoe.Board;
+import com.baeldung.algorithms.mcts.tree.Node;
+import com.baeldung.algorithms.mcts.tree.Tree;
+
+public class MonteCarloTreeSearch {
+
+    private static final int WIN_SCORE = 10;
+    private int level;
+    private int oponent;
+
+    public MonteCarloTreeSearch() {
+        this.level = 3;
+    }
+
+    public int getLevel() {
+        return level;
+    }
+
+    public void setLevel(int level) {
+        this.level = level;
+    }
+
+    private int getMillisForCurrentLevel() {
+        return 2 * (this.level - 1) + 1;
+    }
+
+    public Board findNextMove(Board board, int playerNo) {
+        long start = System.currentTimeMillis();
+        long end = start + 60 * getMillisForCurrentLevel();
+
+        oponent = 3 - playerNo;
+        Tree tree = new Tree();
+        Node rootNode = tree.getRoot();
+        rootNode.getState().setBoard(board);
+        rootNode.getState().setPlayerNo(oponent);
+
+        while (System.currentTimeMillis() < end) {
+            // Phase 1 - Selection
+            Node promisingNode = selectPromisingNode(rootNode);
+            // Phase 2 - Expansion
+            if (promisingNode.getState().getBoard().checkStatus() == Board.IN_PROGRESS)
+                expandNode(promisingNode);
+
+            // Phase 3 - Simulation
+            Node nodeToExplore = promisingNode;
+            if (promisingNode.getChildArray().size() > 0) {
+                nodeToExplore = promisingNode.getRandomChildNode();
+            }
+            int playoutResult = simulateRandomPlayout(nodeToExplore);
+            // Phase 4 - Update
+            backPropogation(nodeToExplore, playoutResult);
+        }
+
+        Node winnerNode = rootNode.getChildWithMaxScore();
+        tree.setRoot(winnerNode);
+        return winnerNode.getState().getBoard();
+    }
+
+    private Node selectPromisingNode(Node rootNode) {
+        Node node = rootNode;
+        while (node.getChildArray().size() != 0) {
+            node = UCT.findBestNodeWithUCT(node);
+        }
+        return node;
+    }
+
+    private void expandNode(Node node) {
+        List<State> possibleStates = node.getState().getAllPossibleStates();
+        possibleStates.forEach(state -> {
+            Node newNode = new Node(state);
+            newNode.setParent(node);
+            newNode.getState().setPlayerNo(node.getState().getOpponent());
+            node.getChildArray().add(newNode);
+        });
+    }
+
+    private void backPropogation(Node nodeToExplore, int playerNo) {
+        Node tempNode = nodeToExplore;
+        while (tempNode != null) {
+            tempNode.getState().incrementVisit();
+            if (tempNode.getState().getPlayerNo() == playerNo)
+                tempNode.getState().addScore(WIN_SCORE);
+            tempNode = tempNode.getParent();
+        }
+    }
+
+    private int simulateRandomPlayout(Node node) {
+        Node tempNode = new Node(node);
+        State tempState = tempNode.getState();
+        int boardStatus = tempState.getBoard().checkStatus();
+
+        if (boardStatus == oponent) {
+            tempNode.getParent().getState().setWinScore(Integer.MIN_VALUE);
+            return boardStatus;
+        }
+        while (boardStatus == Board.IN_PROGRESS) {
+            tempState.togglePlayer();
+            tempState.randomPlay();
+            boardStatus = tempState.getBoard().checkStatus();
+        }
+
+        return boardStatus;
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/mcts/montecarlo/State.java

@@ -0,0 +1,97 @@
+package com.baeldung.algorithms.mcts.montecarlo;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.tictactoe.Board;
+import com.baeldung.algorithms.mcts.tictactoe.Position;
+
+public class State {
+    private Board board;
+    private int playerNo;
+    private int visitCount;
+    private double winScore;
+
+    public State() {
+        board = new Board();
+    }
+
+    public State(State state) {
+        this.board = new Board(state.getBoard());
+        this.playerNo = state.getPlayerNo();
+        this.visitCount = state.getVisitCount();
+        this.winScore = state.getWinScore();
+    }
+
+    public State(Board board) {
+        this.board = new Board(board);
+    }
+
+    Board getBoard() {
+        return board;
+    }
+
+    void setBoard(Board board) {
+        this.board = board;
+    }
+
+    int getPlayerNo() {
+        return playerNo;
+    }
+
+    void setPlayerNo(int playerNo) {
+        this.playerNo = playerNo;
+    }
+
+    int getOpponent() {
+        return 3 - playerNo;
+    }
+
+    public int getVisitCount() {
+        return visitCount;
+    }
+
+    public void setVisitCount(int visitCount) {
+        this.visitCount = visitCount;
+    }
+
+    double getWinScore() {
+        return winScore;
+    }
+
+    void setWinScore(double winScore) {
+        this.winScore = winScore;
+    }
+
+    public List<State> getAllPossibleStates() {
+        List<State> possibleStates = new ArrayList<>();
+        List<Position> availablePositions = this.board.getEmptyPositions();
+        availablePositions.forEach(p -> {
+            State newState = new State(this.board);
+            newState.setPlayerNo(3 - this.playerNo);
+            newState.getBoard().performMove(newState.getPlayerNo(), p);
+            possibleStates.add(newState);
+        });
+        return possibleStates;
+    }
+
+    void incrementVisit() {
+        this.visitCount++;
+    }
+
+    void addScore(double score) {
+        if (this.winScore != Integer.MIN_VALUE)
+            this.winScore += score;
+    }
+
+    void randomPlay() {
+        List<Position> availablePositions = this.board.getEmptyPositions();
+        int totalPossibilities = availablePositions.size();
+        int selectRandom = (int) (Math.random() * ((totalPossibilities - 1) + 1));
+        this.board.performMove(this.playerNo, availablePositions.get(selectRandom));
+    }
+
+    void togglePlayer() {
+        this.playerNo = 3 - this.playerNo;
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/mcts/montecarlo/UCT.java

@@ -0,0 +1,24 @@
+package com.baeldung.algorithms.mcts.montecarlo;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.tree.Node;
+
+public class UCT {
+
+    public static double uctValue(int totalVisit, double nodeWinScore, int nodeVisit) {
+        if (nodeVisit == 0) {
+            return Integer.MAX_VALUE;
+        }
+        return (nodeWinScore / (double) nodeVisit) + 1.41 * Math.sqrt(Math.log(totalVisit) / (double) nodeVisit);
+    }
+
+    static Node findBestNodeWithUCT(Node node) {
+        int parentVisit = node.getState().getVisitCount();
+        return Collections.max(
+          node.getChildArray(),
+          Comparator.comparing(c -> uctValue(parentVisit, c.getState().getWinScore(), c.getState().getVisitCount())));
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/mcts/tictactoe/Board.java

@@ -0,0 +1,155 @@
+package com.baeldung.algorithms.mcts.tictactoe;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class Board {
+    int[][] boardValues;
+    int totalMoves;
+
+    public static final int DEFAULT_BOARD_SIZE = 3;
+
+    public static final int IN_PROGRESS = -1;
+    public static final int DRAW = 0;
+    public static final int P1 = 1;
+    public static final int P2 = 2;
+
+    public Board() {
+        boardValues = new int[DEFAULT_BOARD_SIZE][DEFAULT_BOARD_SIZE];
+    }
+
+    public Board(int boardSize) {
+        boardValues = new int[boardSize][boardSize];
+    }
+
+    public Board(int[][] boardValues) {
+        this.boardValues = boardValues;
+    }
+
+    public Board(int[][] boardValues, int totalMoves) {
+        this.boardValues = boardValues;
+        this.totalMoves = totalMoves;
+    }
+
+    public Board(Board board) {
+        int boardLength = board.getBoardValues().length;
+        this.boardValues = new int[boardLength][boardLength];
+        int[][] boardValues = board.getBoardValues();
+        int n = boardValues.length;
+        for (int i = 0; i < n; i++) {
+            int m = boardValues[i].length;
+            for (int j = 0; j < m; j++) {
+                this.boardValues[i][j] = boardValues[i][j];
+            }
+        }
+    }
+
+    public void performMove(int player, Position p) {
+        this.totalMoves++;
+        boardValues[p.getX()][p.getY()] = player;
+    }
+
+    public int[][] getBoardValues() {
+        return boardValues;
+    }
+
+    public void setBoardValues(int[][] boardValues) {
+        this.boardValues = boardValues;
+    }
+
+    public int checkStatus() {
+        int boardSize = boardValues.length;
+        int maxIndex = boardSize - 1;
+        int[] diag1 = new int[boardSize];
+        int[] diag2 = new int[boardSize];
+        
+        for (int i = 0; i < boardSize; i++) {
+            int[] row = boardValues[i];
+            int[] col = new int[boardSize];
+            for (int j = 0; j < boardSize; j++) {
+                col[j] = boardValues[j][i];
+            }
+            
+            int checkRowForWin = checkForWin(row);
+            if(checkRowForWin!=0)
+                return checkRowForWin;
+            
+            int checkColForWin = checkForWin(col);
+            if(checkColForWin!=0)
+                return checkColForWin;
+            
+            diag1[i] = boardValues[i][i];
+            diag2[i] = boardValues[maxIndex - i][i];
+        }
+
+        int checkDia1gForWin = checkForWin(diag1);
+        if(checkDia1gForWin!=0)
+            return checkDia1gForWin;
+        
+        int checkDiag2ForWin = checkForWin(diag2);
+        if(checkDiag2ForWin!=0)
+            return checkDiag2ForWin;
+        
+        if (getEmptyPositions().size() > 0)
+            return IN_PROGRESS;
+        else
+            return DRAW;
+    }
+
+    private int checkForWin(int[] row) {
+        boolean isEqual = true;
+        int size = row.length;
+        int previous = row[0];
+        for (int i = 0; i < size; i++) {
+            if (previous != row[i]) {
+                isEqual = false;
+                break;
+            }
+            previous = row[i];
+        }
+        if(isEqual)
+            return previous;
+        else
+            return 0;
+    }
+
+    public void printBoard() {
+        int size = this.boardValues.length;
+        for (int i = 0; i < size; i++) {
+            for (int j = 0; j < size; j++) {
+                System.out.print(boardValues[i][j] + " ");
+            }
+            System.out.println();
+        }
+    }
+
+    public List<Position> getEmptyPositions() {
+        int size = this.boardValues.length;
+        List<Position> emptyPositions = new ArrayList<>();
+        for (int i = 0; i < size; i++) {
+            for (int j = 0; j < size; j++) {
+                if (boardValues[i][j] == 0)
+                    emptyPositions.add(new Position(i, j));
+            }
+        }
+        return emptyPositions;
+    }
+
+    public void printStatus() {
+        switch (this.checkStatus()) {
+        case P1:
+            System.out.println("Player 1 wins");
+            break;
+        case P2:
+            System.out.println("Player 2 wins");
+            break;
+        case DRAW:
+            System.out.println("Game Draw");
+            break;
+        case IN_PROGRESS:
+            System.out.println("Game In rogress");
+            break;
+        }
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/mcts/tictactoe/Position.java

@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.mcts.tictactoe;
+
+public class Position {
+    int x;
+    int y;
+
+    public Position() {
+    }
+
+    public Position(int x, int y) {
+        this.x = x;
+        this.y = y;
+    }
+
+    public int getX() {
+        return x;
+    }
+
+    public void setX(int x) {
+        this.x = x;
+    }
+
+    public int getY() {
+        return y;
+    }
+
+    public void setY(int y) {
+        this.y = y;
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/mcts/tree/Node.java

@@ -0,0 +1,78 @@
+package com.baeldung.algorithms.mcts.tree;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.montecarlo.State;
+
+public class Node {
+    State state;
+    Node parent;
+    List<Node> childArray;
+
+    public Node() {
+        this.state = new State();
+        childArray = new ArrayList<>();
+    }
+
+    public Node(State state) {
+        this.state = state;
+        childArray = new ArrayList<>();
+    }
+
+    public Node(State state, Node parent, List<Node> childArray) {
+        this.state = state;
+        this.parent = parent;
+        this.childArray = childArray;
+    }
+
+    public Node(Node node) {
+        this.childArray = new ArrayList<>();
+        this.state = new State(node.getState());
+        if (node.getParent() != null)
+            this.parent = node.getParent();
+        List<Node> childArray = node.getChildArray();
+        for (Node child : childArray) {
+            this.childArray.add(new Node(child));
+        }
+    }
+
+    public State getState() {
+        return state;
+    }
+
+    public void setState(State state) {
+        this.state = state;
+    }
+
+    public Node getParent() {
+        return parent;
+    }
+
+    public void setParent(Node parent) {
+        this.parent = parent;
+    }
+
+    public List<Node> getChildArray() {
+        return childArray;
+    }
+
+    public void setChildArray(List<Node> childArray) {
+        this.childArray = childArray;
+    }
+
+    public Node getRandomChildNode() {
+        int noOfPossibleMoves = this.childArray.size();
+        int selectRandom = (int) (Math.random() * ((noOfPossibleMoves - 1) + 1));
+        return this.childArray.get(selectRandom);
+    }
+
+    public Node getChildWithMaxScore() {
+        return Collections.max(this.childArray, Comparator.comparing(c -> {
+            return c.getState().getVisitCount();
+        }));
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/mcts/tree/Tree.java

@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.mcts.tree;
+
+public class Tree {
+    Node root;
+
+    public Tree() {
+        root = new Node();
+    }
+
+    public Tree(Node root) {
+        this.root = root;
+    }
+
+    public Node getRoot() {
+        return root;
+    }
+
+    public void setRoot(Node root) {
+        this.root = root;
+    }
+
+    public void addChild(Node parent, Node child) {
+        parent.getChildArray().add(child);
+    }
+
+}

algorithms/src/test/java/algorithms/HillClimbingAlgorithmTest.java

@@ -14,17 +14,17 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 public class HillClimbingAlgorithmTest {
-    Stack<String> initStack;
-    Stack<String> goalStack;
+    private Stack<String> initStack;
+    private Stack<String> goalStack;
 
     @Before
     public void initStacks() {
         String blockArr[] = { "B", "C", "D", "A" };
         String goalBlockArr[] = { "A", "B", "C", "D" };
-        initStack = new Stack<String>();
+        initStack = new Stack<>();
         for (String block : blockArr)
             initStack.push(block);
-        goalStack = new Stack<String>();
+        goalStack = new Stack<>();
         for (String block : goalBlockArr)
             goalStack.push(block);
     }
@@ -48,7 +48,7 @@ public class HillClimbingAlgorithmTest {
     @Test
     public void givenCurrentState_whenFindNextState_thenBetterHeuristics() {
         HillClimbing hillClimbing = new HillClimbing();
-        List<Stack<String>> initList = new ArrayList<Stack<String>>();
+        List<Stack<String>> initList = new ArrayList<>();
         initList.add(initStack);
         State currentState = new State(initList);
         currentState.setHeuristics(hillClimbing.getHeuristicsValue(initList, goalStack));

algorithms/src/test/java/algorithms/RtFiniteStateMachineLongRunningUnitTest.java

@@ -1,6 +1,6 @@
 package algorithms;
 
-import com.baeldung.automata.*;
+import com.baeldung.algorithms.automata.*;
 import org.junit.Test;
 
 import static org.junit.Assert.assertTrue;

algorithms/src/test/java/algorithms/mcts/MCTSTest.java

@@ -0,0 +1,92 @@
+package algorithms.mcts;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.algorithms.mcts.montecarlo.MonteCarloTreeSearch;
+import com.baeldung.algorithms.mcts.montecarlo.State;
+import com.baeldung.algorithms.mcts.montecarlo.UCT;
+import com.baeldung.algorithms.mcts.tictactoe.Board;
+import com.baeldung.algorithms.mcts.tictactoe.Position;
+import com.baeldung.algorithms.mcts.tree.Tree;
+
+public class MCTSTest {
+    private Tree gameTree;
+    private MonteCarloTreeSearch mcts;
+
+    @Before
+    public void initGameTree() {
+        gameTree = new Tree();
+        mcts = new MonteCarloTreeSearch();
+    }
+
+    @Test
+    public void givenStats_whenGetUCTForNode_thenUCTMatchesWithManualData() {
+        double uctValue = 15.79;
+        assertEquals(UCT.uctValue(600, 300, 20), uctValue, 0.01);
+    }
+
+    @Test
+    public void giveninitBoardState_whenGetAllPossibleStates_thenNonEmptyList() {
+        State initState = gameTree.getRoot().getState();
+        List<State> possibleStates = initState.getAllPossibleStates();
+        assertTrue(possibleStates.size() > 0);
+    }
+
+    @Test
+    public void givenEmptyBoard_whenPerformMove_thenLessAvailablePossitions() {
+        Board board = new Board();
+        int initAvailablePositions = board.getEmptyPositions().size();
+        board.performMove(Board.P1, new Position(1, 1));
+        int availablePositions = board.getEmptyPositions().size();
+        assertTrue(initAvailablePositions > availablePositions);
+    }
+
+    @Test
+    public void givenEmptyBoard_whenSimulateInterAIPlay_thenGameDraw() {
+        Board board = new Board();
+
+        int player = Board.P1;
+        int totalMoves = Board.DEFAULT_BOARD_SIZE * Board.DEFAULT_BOARD_SIZE;
+        for (int i = 0; i < totalMoves; i++) {
+            board = mcts.findNextMove(board, player);
+            if (board.checkStatus() != -1) {
+                break;
+            }
+            player = 3 - player;
+        }
+        int winStatus = board.checkStatus();
+        assertEquals(winStatus, Board.DRAW);
+    }
+
+    @Test
+    public void givenEmptyBoard_whenLevel1VsLevel3_thenLevel3WinsOrDraw() {
+        Board board = new Board();
+        MonteCarloTreeSearch mcts1 = new MonteCarloTreeSearch();
+        mcts1.setLevel(1);
+        MonteCarloTreeSearch mcts3 = new MonteCarloTreeSearch();
+        mcts3.setLevel(3);
+
+        int player = Board.P1;
+        int totalMoves = Board.DEFAULT_BOARD_SIZE * Board.DEFAULT_BOARD_SIZE;
+        for (int i = 0; i < totalMoves; i++) {
+            if (player == Board.P1)
+                board = mcts3.findNextMove(board, player);
+            else
+                board = mcts1.findNextMove(board, player);
+
+            if (board.checkStatus() != -1) {
+                break;
+            }
+            player = 3 - player;
+        }
+        int winStatus = board.checkStatus();
+        assertTrue(winStatus == Board.DRAW || winStatus == Board.P1);
+    }
+
+}

asciidoctor/README.md

@@ -0,0 +1,3 @@
+### Relevant articles
+
+- [Introduction to Asciidoctor](http://www.baeldung.com/introduction-to-asciidoctor)

asciidoctor/pom.xml

@@ -0,0 +1,56 @@
+<?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">
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>asciidoctor</artifactId>
+    <name>asciidoctor</name>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.asciidoctor</groupId>
+                <artifactId>asciidoctor-maven-plugin</artifactId>
+                <version>1.5.5</version>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.asciidoctor</groupId>
+                        <artifactId>asciidoctorj-pdf</artifactId>
+                        <version>1.5.0-alpha.15</version>
+                    </dependency>
+                </dependencies>
+                <executions>
+                    <execution>
+                        <id>output-pdf</id>
+                        <phase>generate-resources</phase>
+                        <goals>
+                            <goal>process-asciidoc</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <sourceDirectory>src/docs/asciidoc</sourceDirectory>
+                    <outputDirectory>target/docs/asciidoc</outputDirectory>
+                    <backend>pdf</backend>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>        
+        <dependency>
+            <groupId>org.asciidoctor</groupId>
+            <artifactId>asciidoctorj</artifactId>
+            <version>1.5.4</version>
+        </dependency>
+        <dependency>
+            <groupId>org.asciidoctor</groupId>
+            <artifactId>asciidoctorj-pdf</artifactId>
+            <version>1.5.0-alpha.11</version>
+        </dependency>        
+    </dependencies>
+</project>

asciidoctor/src/docs/asciidoc/test.adoc

@@ -0,0 +1,3 @@
+== Introduction Section
+
+Hi. I'm a simple test to see if this Maven build is working. If you see me in a nice PDF, then it means everything is [red]#working#.

asciidoctor/src/main/java/com/baeldung/asciidoctor/AsciidoctorDemo.java

@@ -0,0 +1,33 @@
+package com.baeldung.asciidoctor;
+
+import static org.asciidoctor.Asciidoctor.Factory.create;
+import static org.asciidoctor.OptionsBuilder.options;
+
+import java.io.File;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.asciidoctor.Asciidoctor;
+
+public class AsciidoctorDemo {
+
+    private final Asciidoctor asciidoctor;
+
+    AsciidoctorDemo() {
+        asciidoctor = create();
+    }
+
+    public void generatePDFFromString(final String input) {
+
+        final Map<String, Object> options = options().inPlace(true)
+          .backend("pdf")
+          .asMap();
+
+
+        final String outfile = asciidoctor.convertFile(new File("sample.adoc"), options);
+    }
+
+    String generateHTMLFromString(final String input) {
+        return asciidoctor.convert("Hello _Baeldung_!", new HashMap<String, Object>());
+    }
+}

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

@@ -0,0 +1,13 @@
+package com.baeldung.asciidoctor;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class AsciidoctorDemoTest {
+
+    @Test
+    public void givenString_whenConverting_thenResultingHTMLCode() {
+        final AsciidoctorDemo asciidoctorDemo = new AsciidoctorDemo();
+        Assert.assertEquals(asciidoctorDemo.generateHTMLFromString("Hello _Baeldung_!"), "<div class=\"paragraph\">\n<p>Hello <em>Baeldung</em>!</p>\n</div>");
+    }
+}

core-java-9/src/main/java/com/baeldung/java9/time/TimeApi.java

@@ -0,0 +1,43 @@
+package com.baeldung.java9.time;
+
+import java.time.LocalDate;
+import java.time.temporal.ChronoUnit;
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class TimeApi {
+
+    public static List<Date> getDatesBetweenUsingJava7(Date startDate, Date endDate) {
+        List<Date> datesInRange = new ArrayList<Date>();
+        Calendar calendar = new GregorianCalendar();
+        calendar.setTime(startDate);
+
+        Calendar endCalendar = new GregorianCalendar();
+        endCalendar.setTime(endDate);
+
+        while (calendar.before(endCalendar)) {
+            Date result = calendar.getTime();
+            datesInRange.add(result);
+            calendar.add(Calendar.DATE, 1);
+        }
+        return datesInRange;
+    }
+
+    public static List<LocalDate> getDatesBetweenUsingJava8(LocalDate startDate, LocalDate endDate) {
+        long numOfDaysBetween = ChronoUnit.DAYS.between(startDate, endDate);
+        return IntStream.iterate(0, i -> i + 1)
+                 .limit(numOfDaysBetween)
+                 .mapToObj(i -> startDate.plusDays(i))
+                 .collect(Collectors.toList());
+    }
+
+    public static List<LocalDate> getDatesBetweenUsingJava9(LocalDate startDate, LocalDate endDate) {
+        return startDate.datesUntil(endDate).collect(Collectors.toList());
+    }
+
+}

core-java-9/src/test/java/com/baeldung/java9/time/TimeApiTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.java9.time;
+
+import java.time.LocalDate;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class TimeApiTest {
+
+    @Test
+    public void givenGetDatesBetweenWithUsingJava7_WhenStartEndDate_thenDatesList() {
+        Date startDate = Calendar.getInstance().getTime();
+        Calendar endCalendar = Calendar.getInstance();
+        endCalendar.add(Calendar.DATE, 2);
+        Date endDate = endCalendar.getTime();
+
+        List<Date> dates = TimeApi.getDatesBetweenUsingJava7(startDate, endDate);
+        assertEquals(dates.size(), 2);
+
+        Calendar calendar = Calendar.getInstance();
+        Date date1 = calendar.getTime();
+        assertEquals(dates.get(0).getDay(), date1.getDay());
+        assertEquals(dates.get(0).getMonth(), date1.getMonth());
+        assertEquals(dates.get(0).getYear(), date1.getYear());
+
+        calendar.add(Calendar.DATE, 1);
+        Date date2 = calendar.getTime();
+        assertEquals(dates.get(1).getDay(), date2.getDay());
+        assertEquals(dates.get(1).getMonth(), date2.getMonth());
+        assertEquals(dates.get(1).getYear(), date2.getYear());
+    }
+
+    @Test
+    public void givenGetDatesBetweenWithUsingJava8_WhenStartEndDate_thenDatesList() {
+        LocalDate startDate = LocalDate.now();
+        LocalDate endDate = LocalDate.now().plusDays(2);
+
+        List<LocalDate> dates = TimeApi.getDatesBetweenUsingJava8(startDate, endDate);
+        assertEquals(dates.size(), 2);
+        assertEquals(dates.get(0), LocalDate.now());
+        assertEquals(dates.get(1), LocalDate.now().plusDays(1));
+    }
+
+    @Test
+    public void givenGetDatesBetweenWithUsingJava9_WhenStartEndDate_thenDatesList() {
+        LocalDate startDate = LocalDate.now();
+        LocalDate endDate = LocalDate.now().plusDays(2);
+
+        List<LocalDate> dates = TimeApi.getDatesBetweenUsingJava9(startDate, endDate);
+        assertEquals(dates.size(), 2);
+        assertEquals(dates.get(0), LocalDate.now());
+        assertEquals(dates.get(1), LocalDate.now().plusDays(1));
+    }
+
+}

core-java/.gitignore

@@ -17,9 +17,10 @@
 
 # Files generated by integration tests
 *.txt
+backup-pom.xml
 /bin/
 /temp
 
 #IntelliJ specific
-.idea
+.idea/
 *.iml

core-java/README.md

@@ -113,4 +113,21 @@
 - [Difference Between Wait and Sleep in Java](http://www.baeldung.com/java-wait-and-sleep)
 - [LongAdder and LongAccumulator in Java](http://www.baeldung.com/java-longadder-and-longaccumulator)
 - [Using Java MappedByteBuffer](http://www.baeldung.com/java-mapped-byte-buffer)
-
+- [Dynamic Proxies in Java](http://www.baeldung.com/java-dynamic-proxies)
+- [How to Copy an Array in Java](http://www.baeldung.com/java-array-copy)
+- [Introduction to JDBC](http://www.baeldung.com/java-jdbc)
+- [Guide to CopyOnWriteArrayList](http://www.baeldung.com/java-copy-on-write-arraylist)
+- [Period and Duration in Java](http://www.baeldung.com/java-period-duration)
+- [Converting a Stack Trace to a String in Java](http://www.baeldung.com/java-stacktrace-to-string)
+- [Guide to the Java Phaser](http://www.baeldung.com/java-phaser)
+- [Count Occurrences of a Char in a String](http://www.baeldung.com/java-count-chars)
+- [Java Double Brace Initialization](http://www.baeldung.com/java-double-brace-initialization)
+- [The StackOverflowError in Java](http://www.baeldung.com/java-stack-overflow-error)
+- [Split a String in Java](http://www.baeldung.com/java-split-string)
+- [Introduction to Java Serialization](http://www.baeldung.com/java-serialization)
+- [How to Remove the Last Character of a String?](http://www.baeldung.com/java-remove-last-character-of-string)
+- [Guide to Synchronized Keyword in Java](http://www.baeldung.com/java-synchronized)
+- [ClassNotFoundException vs NoClassDefFoundError](http://www.baeldung.com/java-classnotfoundexception-and-noclassdeffounderror)
+- [Guide to UUID in Java](http://www.baeldung.com/java-uuid)
+- [How to Get the Last Element of a Stream in Java?](http://www.baeldung.com/java-stream-last-element)
+- [Guide to Escaping Characters in Java RegExps](http://www.baeldung.com/java-regexp-escape-char)

core-java/pom.xml

@@ -1,405 +1,404 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-	<modelVersion>4.0.0</modelVersion>
-	<groupId>com.baeldung</groupId>
-	<artifactId>core-java</artifactId>
-	<version>0.1.0-SNAPSHOT</version>
-	<packaging>jar</packaging>
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>core-java</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
 
-	<name>core-java</name>
+    <name>core-java</name>
 
-	<dependencies>
+    <dependencies>
 
-		<!-- utils -->
-		<dependency>
-			<groupId>net.sourceforge.collections</groupId>
-			<artifactId>collections-generic</artifactId>
-			<version>${collections-generic.version}</version>
-		</dependency>
-		<dependency>
-			<groupId>com.google.guava</groupId>
-			<artifactId>guava</artifactId>
-			<version>${guava.version}</version>
-		</dependency>
+        <!-- utils -->
+        <dependency>
+            <groupId>net.sourceforge.collections</groupId>
+            <artifactId>collections-generic</artifactId>
+            <version>${collections-generic.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
 
-		<dependency>
-			<groupId>org.apache.commons</groupId>
-			<artifactId>commons-collections4</artifactId>
-			<version>${commons-collections4.version}</version>
-		</dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
 
-		<dependency>
-			<groupId>commons-io</groupId>
-			<artifactId>commons-io</artifactId>
-			<version>${commons-io.version}</version>
-		</dependency>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons-io.version}</version>
+        </dependency>
 
-		<dependency>
-			<groupId>org.apache.commons</groupId>
-			<artifactId>commons-lang3</artifactId>
-			<version>${commons-lang3.version}</version>
-		</dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
 
-		<dependency>
-			<groupId>org.apache.commons</groupId>
-			<artifactId>commons-math3</artifactId>
-			<version>${commons-math3.version}</version>
-		</dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
 
-		<dependency>
-			<groupId>org.decimal4j</groupId>
-			<artifactId>decimal4j</artifactId>
-			<version>${decimal4j.version}</version>
-		</dependency>
+        <dependency>
+            <groupId>org.decimal4j</groupId>
+            <artifactId>decimal4j</artifactId>
+            <version>${decimal4j.version}</version>
+        </dependency>
 
-		<dependency>
-			<groupId>org.bouncycastle</groupId>
-			<artifactId>bcprov-jdk15on</artifactId>
-			<version>${bouncycastle.version}</version>
-		</dependency>
+        <dependency>
+            <groupId>org.bouncycastle</groupId>
+            <artifactId>bcprov-jdk15on</artifactId>
+            <version>${bouncycastle.version}</version>
+        </dependency>
 
-		<dependency>
-			<groupId>org.unix4j</groupId>
-			<artifactId>unix4j-command</artifactId>
-			<version>${unix4j.version}</version>
-		</dependency>
+        <dependency>
+            <groupId>org.unix4j</groupId>
+            <artifactId>unix4j-command</artifactId>
+            <version>${unix4j.version}</version>
+        </dependency>
 
-		<dependency>
-			<groupId>com.googlecode.grep4j</groupId>
-			<artifactId>grep4j</artifactId>
-			<version>${grep4j.version}</version>
-		</dependency>
-		<!-- web -->
+        <dependency>
+            <groupId>com.googlecode.grep4j</groupId>
+            <artifactId>grep4j</artifactId>
+            <version>${grep4j.version}</version>
+        </dependency>
+        <!-- web -->
 
-		<!-- marshalling -->
+        <!-- marshalling -->
 
-		<dependency>
-			<groupId>com.fasterxml.jackson.core</groupId>
-			<artifactId>jackson-databind</artifactId>
-			<version>${jackson.version}</version>
-		</dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
 
-		<!-- logging -->
+        <!-- logging -->
 
-		<dependency>
-			<groupId>org.slf4j</groupId>
-			<artifactId>slf4j-api</artifactId>
-			<version>${org.slf4j.version}</version>
-		</dependency>
-		<dependency>
-			<groupId>ch.qos.logback</groupId>
-			<artifactId>logback-classic</artifactId>
-			<version>${logback.version}</version>
-			<!-- <scope>runtime</scope> -->
-		</dependency>
-		<dependency>
-			<groupId>org.slf4j</groupId>
-			<artifactId>jcl-over-slf4j</artifactId>
-			<version>${org.slf4j.version}</version>
-			<!-- <scope>runtime</scope> --> <!-- some spring dependencies need to compile against jcl -->
-		</dependency>
-		<dependency> <!-- needed to bridge to slf4j for projects that use the log4j APIs directly -->
-			<groupId>org.slf4j</groupId>
-			<artifactId>log4j-over-slf4j</artifactId>
-			<version>${org.slf4j.version}</version>
-		</dependency>
-		<dependency>
-			<groupId>org.projectlombok</groupId>
-			<artifactId>lombok</artifactId>
-			<version>${lombok.version}</version>
-			<scope>provided</scope>
-		</dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>${org.slf4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>${logback.version}</version>
+            <!-- <scope>runtime</scope> -->
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>jcl-over-slf4j</artifactId>
+            <version>${org.slf4j.version}</version>
+            <!-- <scope>runtime</scope> --> <!-- some spring dependencies need to compile against jcl -->
+        </dependency>
+        <dependency> <!-- needed to bridge to slf4j for projects that use the log4j APIs directly -->
+            <groupId>org.slf4j</groupId>
+            <artifactId>log4j-over-slf4j</artifactId>
+            <version>${org.slf4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
 
-		<!-- test scoped -->
+        <!-- test scoped -->
 
-		<dependency>
-			<groupId>org.hamcrest</groupId>
-			<artifactId>hamcrest-all</artifactId>
-			<version>1.3</version>
-			<scope>test</scope>
-		</dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-all</artifactId>
+            <version>1.3</version>
+            <scope>test</scope>
+        </dependency>
 
-		<dependency>
-			<groupId>junit</groupId>
-			<artifactId>junit</artifactId>
-			<version>${junit.version}</version>
-			<scope>test</scope>
-		</dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
 
-		<dependency>
-			<groupId>org.hamcrest</groupId>
-			<artifactId>hamcrest-core</artifactId>
-			<version>${org.hamcrest.version}</version>
-			<scope>test</scope>
-		</dependency>
-		<dependency>
-			<groupId>org.hamcrest</groupId>
-			<artifactId>hamcrest-library</artifactId>
-			<version>${org.hamcrest.version}</version>
-			<scope>test</scope>
-		</dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-core</artifactId>
+            <version>${org.hamcrest.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-library</artifactId>
+            <version>${org.hamcrest.version}</version>
+            <scope>test</scope>
+        </dependency>
 
-		<dependency>
-			<groupId>org.assertj</groupId>
-			<artifactId>assertj-core</artifactId>
-			<version>${assertj.version}</version>
-			<scope>test</scope>
-		</dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
 
-		<dependency>
-			<groupId>org.mockito</groupId>
-			<artifactId>mockito-core</artifactId>
-			<version>${mockito.version}</version>
-			<scope>test</scope>
-		</dependency>
-		<dependency>
-			<groupId>com.jayway.awaitility</groupId>
-			<artifactId>awaitility</artifactId>
-			<version>${avaitility.version}</version>
-			<scope>test</scope>
-		</dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>${mockito.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.jayway.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>${avaitility.version}</version>
+            <scope>test</scope>
+        </dependency>
 
-		<dependency>
-			<groupId>commons-codec</groupId>
-			<artifactId>commons-codec</artifactId>
-			<version>${commons-codec.version}</version>
-		</dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
 
-		<dependency>
-			<groupId>org.javamoney</groupId>
-			<artifactId>moneta</artifactId>
-			<version>1.1</version>
-		</dependency>
+        <dependency>
+            <groupId>org.javamoney</groupId>
+            <artifactId>moneta</artifactId>
+            <version>1.1</version>
+        </dependency>
 
-		<dependency>
-			<groupId>org.owasp.esapi</groupId>
-			<artifactId>esapi</artifactId>
-			<version>2.1.0.1</version>
-		</dependency>
+        <dependency>
+            <groupId>org.owasp.esapi</groupId>
+            <artifactId>esapi</artifactId>
+            <version>2.1.0.1</version>
+        </dependency>
 
-		<dependency>
-			<groupId>com.sun.messaging.mq</groupId>
-			<artifactId>fscontext</artifactId>
-			<version>${fscontext.version}</version>
-		</dependency>
-	</dependencies>
+        <dependency>
+            <groupId>com.sun.messaging.mq</groupId>
+            <artifactId>fscontext</artifactId>
+            <version>${fscontext.version}</version>
+        </dependency>
+    </dependencies>
 
-	<build>
-		<finalName>core-java</finalName>
-		<resources>
-			<resource>
-				<directory>src/main/resources</directory>
-				<filtering>true</filtering>
-			</resource>
-		</resources>
+    <build>
+        <finalName>core-java</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
 
-		<plugins>
+        <plugins>
 
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-compiler-plugin</artifactId>
-				<version>${maven-compiler-plugin.version}</version>
-				<configuration>
-					<source>1.8</source>
-					<target>1.8</target>
-				</configuration>
-			</plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
 
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-surefire-plugin</artifactId>
-				<configuration>
-					<excludes>
-						<exclude>**/*IntegrationTest.java</exclude>
-						<exclude>**/*LongRunningUnitTest.java</exclude>
-						<exclude>**/*ManualTest.java</exclude>
-					</excludes>
-					<testFailureIgnore>true</testFailureIgnore>
-				</configuration>
-			</plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <excludes>
+                        <exclude>**/*IntegrationTest.java</exclude>
+                        <exclude>**/*LongRunningUnitTest.java</exclude>
+                        <exclude>**/*ManualTest.java</exclude>
+                    </excludes>
+                    <testFailureIgnore>true</testFailureIgnore>
+                </configuration>
+            </plugin>
 
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-dependency-plugin</artifactId>
-				<executions>
-					<execution>
-						<id>copy-dependencies</id>
-						<phase>prepare-package</phase>
-						<goals>
-							<goal>copy-dependencies</goal>
-						</goals>
-						<configuration>
-							<outputDirectory>${project.build.directory}/libs</outputDirectory>
-						</configuration>
-					</execution>
-				</executions>
-			</plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-dependency-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>copy-dependencies</id>
+                        <phase>prepare-package</phase>
+                        <goals>
+                            <goal>copy-dependencies</goal>
+                        </goals>
+                        <configuration>
+                            <outputDirectory>${project.build.directory}/libs</outputDirectory>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
 
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-jar-plugin</artifactId>
-				<configuration>
-					<archive>
-						<manifest>
-							<addClasspath>true</addClasspath>
-							<classpathPrefix>libs/</classpathPrefix>
-							<mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
-						</manifest>
-					</archive>
-				</configuration>
-			</plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <addClasspath>true</addClasspath>
+                            <classpathPrefix>libs/</classpathPrefix>
+                            <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
 
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-assembly-plugin</artifactId>
-				<executions>
-					<execution>
-						<phase>package</phase>
-						<goals>
-							<goal>single</goal>
-						</goals>
-						<configuration>
-							<archiveBaseDirectory>${project.basedir}</archiveBaseDirectory>
-							<archive>
-								<manifest>
-									<mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
-								</manifest>
-							</archive>
-							<descriptorRefs>
-								<descriptorRef>jar-with-dependencies</descriptorRef>
-							</descriptorRefs>
-						</configuration>
-					</execution>
-				</executions>
-			</plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                        <configuration>
+                            <archiveBaseDirectory>${project.basedir}</archiveBaseDirectory>
+                            <archive>
+                                <manifest>
+                                    <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                                </manifest>
+                            </archive>
+                            <descriptorRefs>
+                                <descriptorRef>jar-with-dependencies</descriptorRef>
+                            </descriptorRefs>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
 
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-shade-plugin</artifactId>
-				<executions>
-					<execution>
-						<goals>
-							<goal>shade</goal>
-						</goals>
-						<configuration>
-							<shadedArtifactAttached>true</shadedArtifactAttached>
-							<transformers>
-								<transformer
-									implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
-									<mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
-								</transformer>
-							</transformers>
-						</configuration>
-					</execution>
-				</executions>
-			</plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <shadedArtifactAttached>true</shadedArtifactAttached>
+                            <transformers>
+                                <transformer
+                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                                </transformer>
+                            </transformers>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
 
-			<plugin>
-				<groupId>com.jolira</groupId>
-				<artifactId>onejar-maven-plugin</artifactId>
-				<executions>
-					<execution>
-						<configuration>
-							<mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
-							<attachToBuild>true</attachToBuild>
-							<filename>${project.build.finalName}-onejar.${project.packaging}</filename>
-						</configuration>
-						<goals>
-							<goal>one-jar</goal>
-						</goals>
-					</execution>
-				</executions>
-			</plugin>
+            <plugin>
+                <groupId>com.jolira</groupId>
+                <artifactId>onejar-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <configuration>
+                            <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                            <attachToBuild>true</attachToBuild>
+                            <filename>${project.build.finalName}-onejar.${project.packaging}</filename>
+                        </configuration>
+                        <goals>
+                            <goal>one-jar</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
 
-			<plugin>
-				<groupId>org.springframework.boot</groupId>
-				<artifactId>spring-boot-maven-plugin</artifactId>
-				<executions>
-					<execution>
-						<goals>
-							<goal>repackage</goal>
-						</goals>
-						<configuration>
-							<classifier>spring-boot</classifier>
-							<mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
-						</configuration>
-					</execution>
-				</executions>
-			</plugin>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>repackage</goal>
+                        </goals>
+                        <configuration>
+                            <classifier>spring-boot</classifier>
+                            <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
 
-		</plugins>
+        </plugins>
 
-	</build>
+    </build>
 
-	<profiles>
-		<profile>
-			<id>integration</id>
-			<build>
-				<plugins>
-					<plugin>
-						<groupId>org.apache.maven.plugins</groupId>
-						<artifactId>maven-surefire-plugin</artifactId>
-						<executions>
-							<execution>
-								<phase>integration-test</phase>
-								<goals>
-									<goal>test</goal>
-								</goals>
-								<configuration>
-									<excludes>
-										<exclude>**/*ManualTest.java</exclude>
-									</excludes>
-									<includes>
-										<include>**/*IntegrationTest.java</include>
-									</includes>
-								</configuration>
-							</execution>
-						</executions>
-						<configuration>
-							<systemPropertyVariables>
-								<test.mime>json</test.mime>
-							</systemPropertyVariables>
-						</configuration>
-					</plugin>
-				</plugins>
-			</build>
-		</profile>
-	</profiles>
+    <profiles>
+        <profile>
+            <id>integration</id>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-surefire-plugin</artifactId>
+                        <executions>
+                            <execution>
+                                <phase>integration-test</phase>
+                                <goals>
+                                    <goal>test</goal>
+                                </goals>
+                                <configuration>
+                                    <excludes>
+                                        <exclude>**/*ManualTest.java</exclude>
+                                    </excludes>
+                                    <includes>
+                                        <include>**/*IntegrationTest.java</include>
+                                    </includes>
+                                </configuration>
+                            </execution>
+                        </executions>
+                        <configuration>
+                            <systemPropertyVariables>
+                                <test.mime>json</test.mime>
+                            </systemPropertyVariables>
+                        </configuration>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
 
-	<properties>
-		<!-- marshalling -->
-		<jackson.version>2.8.5</jackson.version>
+    <properties>
+        <!-- marshalling -->
+        <jackson.version>2.8.5</jackson.version>
 
-		<!-- logging -->
-		<org.slf4j.version>1.7.21</org.slf4j.version>
-		<logback.version>1.1.7</logback.version>
+        <!-- logging -->
+        <org.slf4j.version>1.7.21</org.slf4j.version>
+        <logback.version>1.1.7</logback.version>
 
-		<!-- util -->
-		<guava.version>21.0</guava.version>
-		<commons-lang3.version>3.5</commons-lang3.version>
-		<bouncycastle.version>1.55</bouncycastle.version>
-		<commons-codec.version>1.10</commons-codec.version>
-		<commons-math3.version>3.6.1</commons-math3.version>
-		<decimal4j.version>1.0.3</decimal4j.version>
-		<commons-io.version>2.5</commons-io.version>
-		<commons-collections4.version>4.1</commons-collections4.version>
-		<collections-generic.version>4.01</collections-generic.version>
-		<unix4j.version>0.4</unix4j.version>
-		<grep4j.version>1.8.7</grep4j.version>
-		<lombok.version>1.16.12</lombok.version>
-		<fscontext.version>4.6-b01</fscontext.version>
+        <!-- util -->
+        <guava.version>21.0</guava.version>
+        <commons-lang3.version>3.5</commons-lang3.version>
+        <bouncycastle.version>1.55</bouncycastle.version>
+        <commons-codec.version>1.10</commons-codec.version>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <decimal4j.version>1.0.3</decimal4j.version>
+        <commons-io.version>2.5</commons-io.version>
+        <commons-collections4.version>4.1</commons-collections4.version>
+        <collections-generic.version>4.01</collections-generic.version>
+        <unix4j.version>0.4</unix4j.version>
+        <grep4j.version>1.8.7</grep4j.version>
+        <lombok.version>1.16.12</lombok.version>
+        <fscontext.version>4.6-b01</fscontext.version>
 
-		<!-- testing -->
-		<org.hamcrest.version>1.3</org.hamcrest.version>
-		<junit.version>4.12</junit.version>
-		<mockito.version>1.10.19</mockito.version>
-		<assertj.version>3.6.1</assertj.version>
-		<avaitility.version>1.7.0</avaitility.version>
+        <!-- testing -->
+        <org.hamcrest.version>1.3</org.hamcrest.version>
+        <junit.version>4.12</junit.version>
+        <mockito.version>1.10.19</mockito.version>
+        <assertj.version>3.6.1</assertj.version>
+        <avaitility.version>1.7.0</avaitility.version>
 
-		<!-- maven plugins -->
-		<maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
-		<maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
-
-	</properties>
+        <!-- maven plugins -->
+        <maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
+        <maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
 
+    </properties>
 </project>

core-java/src/main/java/com/baeldung/concurrent/cyclicbarrier/CyclicBarrierDemo.java

@@ -0,0 +1,86 @@
+package com.baeldung.concurrent.cyclicbarrier;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+import java.util.concurrent.BrokenBarrierException;
+import java.util.concurrent.CyclicBarrier;
+
+/**
+ * Created by cv on 24/6/17.
+ */
+public class CyclicBarrierDemo {
+
+    private CyclicBarrier cyclicBarrier;
+    private List<List<Integer>> partialResults = Collections.synchronizedList(new ArrayList<>());
+    private Random random = new Random();
+    private int NUM_PARTIAL_RESULTS;
+    private int NUM_WORKERS;
+
+
+    public void runSimulation(int numWorkers, int numberOfPartialResults) {
+        NUM_PARTIAL_RESULTS = numberOfPartialResults;
+        NUM_WORKERS = numWorkers;
+
+        cyclicBarrier = new CyclicBarrier(NUM_WORKERS, new AggregatorThread());
+        System.out.println("Spawning " + NUM_WORKERS + " worker threads to compute "
+                + NUM_PARTIAL_RESULTS + " partial results each");
+        for (int i = 0; i < NUM_WORKERS; i++) {
+            Thread worker = new Thread(new NumberCruncherThread());
+            worker.setName("Thread " + i);
+            worker.start();
+        }
+    }
+
+    class NumberCruncherThread implements Runnable {
+
+        @Override
+        public void run() {
+            String thisThreadName = Thread.currentThread().getName();
+            List<Integer> partialResult = new ArrayList<>();
+            for (int i = 0; i < NUM_PARTIAL_RESULTS; i++) {
+                Integer num = random.nextInt(10);
+                System.out.println(thisThreadName
+                        + ": Crunching some numbers! Final result - " + num);
+                partialResult.add(num);
+            }
+            partialResults.add(partialResult);
+            try {
+                System.out.println(thisThreadName + " waiting for others to reach barrier.");
+                cyclicBarrier.await();
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            } catch (BrokenBarrierException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    class AggregatorThread implements Runnable {
+
+        @Override
+        public void run() {
+            String thisThreadName = Thread.currentThread().getName();
+            System.out.println(thisThreadName + ": Computing final sum of " + NUM_WORKERS
+                    + " workers, having " + NUM_PARTIAL_RESULTS + " results each.");
+            int sum = 0;
+            for (List<Integer> threadResult : partialResults) {
+                System.out.print("Adding ");
+                for (Integer partialResult : threadResult) {
+                    System.out.print(partialResult+" ");
+                    sum += partialResult;
+                }
+                System.out.println();
+            }
+            System.out.println(Thread.currentThread().getName() + ": Final result = " + sum);
+        }
+
+    }
+
+    public static void main(String[] args) {
+        CyclicBarrierDemo play = new CyclicBarrierDemo();
+        play.runSimulation(5, 3);
+    }
+
+}

core-java/src/main/java/com/baeldung/java/reflection/DynamicGreeter.java

@@ -0,0 +1,23 @@
+package com.baeldung.java.reflection;
+
+import java.lang.annotation.Annotation;
+
+public class DynamicGreeter implements Greeter {
+    
+    private String greet;
+
+    public DynamicGreeter(String greet) {
+        this.greet = greet;
+    }
+
+    @Override
+    public Class<? extends Annotation> annotationType() {
+        return DynamicGreeter.class;
+    }
+
+    @Override
+    public String greet() {
+        return greet;
+    }
+
+}

core-java/src/main/java/com/baeldung/java/reflection/Greeter.java

@@ -0,0 +1,10 @@
+package com.baeldung.java.reflection;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Greeter {
+    
+    public String greet() default ""; 
+}

core-java/src/main/java/com/baeldung/java/reflection/GreetingAnnotation.java

@@ -0,0 +1,58 @@
+package com.baeldung.java.reflection;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.Map;
+
+public class GreetingAnnotation {
+   
+    private static final String ANNOTATION_METHOD = "annotationData";
+    private static final String ANNOTATION_FIELDS = "declaredAnnotations";
+    private static final String ANNOTATIONS = "annotations";
+
+    public static void main(String ...args) {
+        Greeter greetings = Greetings.class.getAnnotation(Greeter.class);
+        System.err.println("Hello there, " + greetings.greet() + " !!");
+
+        Greeter targetValue = new DynamicGreeter("Good evening");
+        //alterAnnotationValueJDK8(Greetings.class, Greeter.class, targetValue);
+        alterAnnotationValueJDK7(Greetings.class, Greeter.class, targetValue);
+        
+        greetings = Greetings.class.getAnnotation(Greeter.class);
+        System.err.println("Hello there, " + greetings.greet() + " !!");
+    }
+    
+    @SuppressWarnings("unchecked")
+    public static void alterAnnotationValueJDK8(Class<?> targetClass, Class<? extends Annotation> targetAnnotation, Annotation targetValue) {
+        try {
+            Method method = Class.class.getDeclaredMethod(ANNOTATION_METHOD, null);
+            method.setAccessible(true);
+
+            Object annotationData = method.invoke(targetClass);
+            
+            Field annotations = annotationData.getClass().getDeclaredField(ANNOTATIONS);
+            annotations.setAccessible(true);
+
+            Map<Class<? extends Annotation>, Annotation> map = (Map<Class<? extends Annotation>, Annotation>) annotations.get(annotationData);
+            map.put(targetAnnotation, targetValue);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+    
+    @SuppressWarnings("unchecked")
+    public static void alterAnnotationValueJDK7(Class<?> targetClass, Class<? extends Annotation> targetAnnotation, Annotation targetValue) {
+        try {            
+            Field annotations = Class.class.getDeclaredField(ANNOTATIONS);
+            annotations.setAccessible(true);
+
+            Map<Class<? extends Annotation>, Annotation> map = (Map<Class<? extends Annotation>, Annotation>) annotations.get(targetClass);
+            System.out.println(map);
+            map.put(targetAnnotation, targetValue);
+            System.out.println(map);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}

core-java/src/main/java/com/baeldung/java/reflection/Greetings.java

@@ -0,0 +1,6 @@
+package com.baeldung.java.reflection;
+
+@Greeter(greet="Good morning")
+public class Greetings {
+
+}

core-java/src/main/java/com/baeldung/javanetworking/url/URLDemo.java

@@ -0,0 +1,69 @@
+package com.baeldung.javanetworking.url;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.net.URLConnection;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class URLDemo {
+    private final Logger log = LoggerFactory.getLogger(URLDemo.class);
+
+    String URLSTRING = "https://wordpress.org:443/support/topic/page-jumps-within-wordpress/?replies=3#post-2278484";
+    // parsed locator
+    String URLPROTOCOL = "https";
+    // final static String URLAUTHORITY = "wordpress.org:443";
+    String URLHOST = "wordpress.org";
+    String URLPATH = "/support/topic/page-jumps-within-wordpress/";
+    // final static String URLFILENAME = "/support/topic/page-jumps-within-wordpress/?replies=3";
+    // final static int URLPORT = 443;
+    int URLDEFAULTPORT = 443;
+    String URLQUERY = "replies=3";
+    String URLREFERENCE = "post-2278484";
+    String URLCOMPOUND = URLPROTOCOL + "://" + URLHOST + ":" + URLDEFAULTPORT + URLPATH + "?" + URLQUERY + "#" + URLREFERENCE;
+
+    URL url;
+    URLConnection urlConnection = null;
+    HttpURLConnection connection = null;
+    BufferedReader in = null;
+    String urlContent = "";
+
+    public String testURL(String urlString) throws IOException, IllegalArgumentException {
+        String urlStringCont = "";
+        // comment the if clause if experiment with URL
+        /*if (!URLSTRING.equals(urlString)) {
+            throw new IllegalArgumentException("URL String argument is not proper: " + urlString);
+        }*/
+        // creating URL object
+        url = new URL(urlString);
+        // get URL connection
+        urlConnection = url.openConnection();
+        connection = null;
+        // we can check, if connection is proper type
+        if (urlConnection instanceof HttpURLConnection) {
+            connection = (HttpURLConnection) urlConnection;
+        } else {
+            log.info("Please enter an HTTP URL");
+            throw new IOException("HTTP URL is not correct");
+        }
+        // we can check response code (200 OK is expected)
+        log.info(connection.getResponseCode() + " " + connection.getResponseMessage());
+        in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
+        String current;
+
+        while ((current = in.readLine()) != null) {
+            urlStringCont += current;
+        }
+        return urlStringCont;
+    }
+
+    public static void main(String[] args) throws Exception {
+        URLDemo demo = new URLDemo();
+        String content = demo.testURL(demo.URLCOMPOUND);
+        demo.log.info(content);
+    }
+}

core-java/src/main/java/com/baeldung/map/iteration/MapIteration.java

@@ -0,0 +1,71 @@
+package com.baeldung.map.iteration;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+
+public class MapIteration {
+
+    public static void main(String[] args) {
+        MapIteration mapIteration = new MapIteration();
+        Map<String, Integer> map = new HashMap<>();
+
+        map.put("One", 1);
+        map.put("Three", 3);
+        map.put("Two", 2);
+
+        System.out.println("Iterating Keys of Map Using KeySet");
+        mapIteration.iterateKeys(map);
+
+        System.out.println("Iterating Map Using Entry Set");
+        mapIteration.iterateUsingEntrySet(map);
+
+        System.out.println("Iterating Using Iterator and Map Entry");
+        mapIteration.iterateUsingIteratorAndEntry(map);
+
+        System.out.println("Iterating Using KeySet and For Each");
+        mapIteration.iterateUsingKeySetAndForeach(map);
+
+        System.out.println("Iterating Map Using Lambda Expression");
+        mapIteration.iterateUsingLambda(map);
+
+        System.out.println("Iterating Using Stream API");
+        mapIteration.iterateUsingStreamAPI(map);
+    }
+
+    public void iterateUsingEntrySet(Map<String, Integer> map) {
+        for (Map.Entry<String, Integer> entry : map.entrySet()) {
+            System.out.println(entry.getKey() + ":" + entry.getValue());
+        }
+    }
+
+    public void iterateUsingLambda(Map<String, Integer> map) {
+        map.forEach((k, v) -> System.out.println((k + ":" + v)));
+    }
+
+    public void iterateUsingIteratorAndEntry(Map<String, Integer> map) {
+        Iterator<Map.Entry<String, Integer>> iterator = map.entrySet().iterator();
+        while (iterator.hasNext()) {
+            Map.Entry<String, Integer> pair = iterator.next();
+            System.out.println(pair.getKey() + ":" + pair.getValue());
+        }
+    }
+
+    public void iterateUsingKeySetAndForeach(Map<String, Integer> map) {
+        for (String key : map.keySet()) {
+            System.out.println(key + ":" + map.get(key));
+        }
+    }
+
+    public void iterateUsingStreamAPI(Map<String, Integer> map) {
+        map.entrySet().stream().forEach(e -> System.out.println(e.getKey() + ":" + e.getValue()));
+    }
+
+    public void iterateKeys(Map<String, Integer> map) {
+        for (String key : map.keySet()) {
+            System.out.println(key);
+        }
+
+    }
+
+}

core-java/src/main/java/com/baeldung/maths/FloatingPointArithmetic.java

@@ -0,0 +1,51 @@
+package com.baeldung.maths;
+
+import java.math.BigDecimal;
+
+public class FloatingPointArithmetic {
+    public static void main(String[] args) {
+        
+        double a = 13.22;
+        double b = 4.88;
+        double c = 21.45;
+        
+        System.out.println("a =         " + a);
+        System.out.println("b =         " + b);
+        System.out.println("c =         " + c);
+        
+        double sum_ab = a + b;
+        System.out.println("a + b =     " + sum_ab);
+        
+        double abc =  a + b + c;
+        System.out.println("a + b + c = " + abc);
+        
+        double ab_c = sum_ab + c;
+        System.out.println("ab + c =    " + ab_c);
+        
+        double sum_ac = a + c;
+        System.out.println("a + c =     " + sum_ac);
+        
+        double acb = a + c + b;
+        System.out.println("a + c + b = " + acb);
+        
+        double ac_b = sum_ac + b;
+        System.out.println("ac + b =    " + ac_b);
+        
+        double ab = 18.1;
+        double ac = 34.67;
+        double sum_ab_c = ab + c;
+        double sum_ac_b = ac + b;
+        System.out.println("ab + c =    " + sum_ab_c);
+        System.out.println("ac + b =    " + sum_ac_b);
+        
+        BigDecimal d = new BigDecimal(String.valueOf(a));
+        BigDecimal e = new BigDecimal(String.valueOf(b));
+        BigDecimal f = new BigDecimal(String.valueOf(c));
+        
+        BigDecimal def = d.add(e).add(f);
+        BigDecimal dfe = d.add(f).add(e);
+        
+        System.out.println("d + e + f = " + def);
+        System.out.println("d + f + e = " + dfe);
+    }
+}

core-java/src/main/java/com/baeldung/reflection/BaeldungReflectionUtils.java

@@ -0,0 +1,39 @@
+package com.baeldung.reflection;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.beans.Introspector;
+import java.beans.PropertyDescriptor;
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+class BaeldungReflectionUtils {
+
+    private static final Logger LOG = LoggerFactory.getLogger(BaeldungReflectionUtils.class);
+
+    static List<String> getNullPropertiesList(Customer customer) throws Exception {
+        PropertyDescriptor[] propDescArr = Introspector.getBeanInfo(Customer.class, Object.class).getPropertyDescriptors();
+
+        return Arrays.stream(propDescArr)
+          .filter(nulls(customer))
+          .map(PropertyDescriptor::getName)
+          .collect(Collectors.toList());
+    }
+
+    private static Predicate<PropertyDescriptor> nulls(Customer customer) {
+        return pd -> {
+            boolean result = false;
+            try {
+                Method getterMethod = pd.getReadMethod();
+                result = (getterMethod != null && getterMethod.invoke(customer) == null);
+            } catch (Exception e) {
+                LOG.error("error invoking getter method");
+            }
+            return result;
+        };
+    }
+}

core-java/src/main/java/com/baeldung/reflection/Customer.java

@@ -0,0 +1,56 @@
+package com.baeldung.reflection;
+
+public class Customer {
+
+    private Integer id;
+    private String name;
+    private String emailId;
+    private Long phoneNumber;
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getEmailId() {
+        return emailId;
+    }
+
+    public void setEmailId(String emailId) {
+        this.emailId = emailId;
+    }
+
+    @Override
+    public String toString() {
+        return "Customer [id=" + id + ", name=" + name + ", emailId=" + emailId + ", phoneNumber=" +
+          phoneNumber + "]";
+    }
+
+    Customer(Integer id, String name, String emailId, Long phoneNumber) {
+        super();
+        this.id = id;
+        this.name = name;
+        this.emailId = emailId;
+        this.phoneNumber = phoneNumber;
+    }
+
+    public Long getPhoneNumber() {
+        return phoneNumber;
+    }
+
+    public void setPhoneNumber(Long phoneNumber) {
+        this.phoneNumber = phoneNumber;
+    }
+
+}

core-java/src/main/java/com/baeldung/serialization/Address.java

@@ -1,4 +1,4 @@
-package com.baeuldung.serialization;
+package com.baeldung.serialization;
 
 public class Address {
 

core-java/src/main/java/com/baeldung/serialization/Employee.java

@@ -1,4 +1,4 @@
-package com.baeuldung.serialization;
+package com.baeldung.serialization;
 
 import java.io.IOException;
 import java.io.ObjectInputStream;

core-java/src/main/java/com/baeldung/serialization/Person.java

@@ -1,4 +1,4 @@
-package com.baeuldung.serialization;
+package com.baeldung.serialization;
 import java.io.Serializable;
 
 public class Person implements Serializable {

core-java/src/main/java/log4j.properties

@@ -0,0 +1,9 @@
+# Set root logger level to DEBUG and its only appender to A1.
+log4j.rootLogger=DEBUG, A1
+
+# A1 is set to be a ConsoleAppender.
+log4j.appender.A1=org.apache.log4j.ConsoleAppender
+
+# A1 uses PatternLayout.
+log4j.appender.A1.layout=org.apache.log4j.PatternLayout
+log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

core-java/src/test/java/com/baeldung/completablefuture/CompletableFutureLongRunningUnitTest.java

@@ -11,9 +11,9 @@ import java.util.stream.Stream;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
-public class CompletableFutureUnitTest {
+public class CompletableFutureLongRunningUnitTest {
 
-    private static final Logger LOG = LoggerFactory.getLogger(CompletableFutureUnitTest.class);
+    private static final Logger LOG = LoggerFactory.getLogger(CompletableFutureLongRunningUnitTest.class);
 
 
     @Test

core-java/src/test/java/com/baeldung/filesystem/jndi/test/LookupFSJNDIIntegrationTest.java

@@ -11,13 +11,12 @@ import org.junit.Test;
 
 import com.baeldung.filesystem.jndi.LookupFSJNDI;
 
-public class LookupFSJNDITest {
+public class LookupFSJNDIIntegrationTest {
     LookupFSJNDI fsjndi;
-    File file;
     InitialContext ctx = null;
     final String FILENAME = "test.find";
 
-    public LookupFSJNDITest() {
+    public LookupFSJNDIIntegrationTest() {
         try {
             fsjndi = new LookupFSJNDI();
         } catch (NamingException e) {

core-java/src/test/java/com/baeldung/java/currentmethod/CurrentlyExecutedMethodFinderTest.java

@@ -0,0 +1,43 @@
+package com.baeldung.java.currentmethod;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * The class presents various ways of finding the name of currently executed method.
+ */
+public class CurrentlyExecutedMethodFinderTest {
+
+    @Test
+    public void givenCurrentThread_whenGetStackTrace_thenFindMethod() {
+        final StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
+        assertEquals("givenCurrentThread_whenGetStackTrace_thenFindMethod", stackTrace[1].getMethodName());
+    }
+
+    @Test
+    public void givenException_whenGetStackTrace_thenFindMethod() {
+        String methodName = new Exception().getStackTrace()[0].getMethodName();
+        assertEquals("givenException_whenGetStackTrace_thenFindMethod", methodName);
+    }
+
+    @Test
+    public void givenThrowable_whenGetStacktrace_thenFindMethod() {
+        StackTraceElement[] stackTrace = new Throwable().getStackTrace();
+        assertEquals("givenThrowable_whenGetStacktrace_thenFindMethod", stackTrace[0].getMethodName());
+    }
+
+    @Test
+    public void givenObject_whenGetEnclosingMethod_thenFindMethod() {
+        String methodName = new Object() {}.getClass().getEnclosingMethod().getName();
+        assertEquals("givenObject_whenGetEnclosingMethod_thenFindMethod", methodName);
+    }
+
+    @Test
+    public void givenLocal_whenGetEnclosingMethod_thenFindMethod() {
+        class Local {};
+        String methodName = Local.class.getEnclosingMethod().getName();
+        assertEquals("givenLocal_whenGetEnclosingMethod_thenFindMethod", methodName);
+    }
+
+}

core-java/src/test/java/com/baeldung/javanetworking/url/test/URLDemoTest.java

@@ -0,0 +1,106 @@
+package com.baeldung.javanetworking.url.test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLConnection;
+
+import org.junit.BeforeClass;
+import org.junit.FixMethodOrder;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.baeldung.javanetworking.url.URLDemo;
+
+@FixMethodOrder
+public class URLDemoTest {
+    private final Logger log = LoggerFactory.getLogger(URLDemo.class);
+    static String URLSTRING = "https://wordpress.org:443/support/topic/page-jumps-within-wordpress/?replies=3#post-2278484";
+    // parsed locator
+    static String URLPROTOCOL = "https";
+    String URLAUTHORITY = "wordpress.org:443";
+    static String URLHOST = "wordpress.org";
+    static String URLPATH = "/support/topic/page-jumps-within-wordpress/";
+    String URLFILENAME = "/support/topic/page-jumps-within-wordpress/?replies=3";
+    int URLPORT = 443;
+    static int URLDEFAULTPORT = 443;
+    static String URLQUERY = "replies=3";
+    static String URLREFERENCE = "post-2278484";
+    static String URLCOMPOUND = URLPROTOCOL + "://" + URLHOST + ":" + URLDEFAULTPORT + URLPATH + "?" + URLQUERY + "#" + URLREFERENCE;
+
+    static URL url;
+    URLConnection urlConnection = null;
+    HttpURLConnection connection = null;
+    BufferedReader in = null;
+    String urlContent = "";
+
+    @BeforeClass
+    public static void givenEmplyURL_whenInitializeURL_thenSuccess() throws MalformedURLException {
+        url = new URL(URLCOMPOUND);
+    }
+
+    // check parsed URL
+    @Test
+    public void givenURL_whenURLIsParsed_thenSuccess() {
+        assertNotNull("URL is null", url);
+        assertEquals("URL string is not equal", url.toString(), URLSTRING);
+        assertEquals("Protocol is not equal", url.getProtocol(), URLPROTOCOL);
+        assertEquals("Authority is not equal", url.getAuthority(), URLAUTHORITY);
+        assertEquals("Host string is not equal", url.getHost(), URLHOST);
+        assertEquals("Path string is not equal", url.getPath(), URLPATH);
+        assertEquals("File string is not equal", url.getFile(), URLFILENAME);
+        assertEquals("Port number is not equal", url.getPort(), URLPORT);
+        assertEquals("Default port number is not equal", url.getDefaultPort(), URLDEFAULTPORT);
+        assertEquals("Query string is not equal", url.getQuery(), URLQUERY);
+        assertEquals("Reference string is not equal", url.getRef(), URLREFERENCE);
+    }
+
+    // Obtain the content from location
+    @Test
+    public void givenURL_whenOpenConnectionAndContentIsNotEmpty_thenSuccess() throws IOException {
+        try {
+            urlConnection = url.openConnection();
+        } catch (IOException ex) {
+            urlConnection = null;
+            ex.printStackTrace();
+        }
+        assertNotNull("URL Connection is null", urlConnection);
+
+        connection = null;
+        assertTrue("URLConnection is not HttpURLConnection", urlConnection instanceof HttpURLConnection);
+        if (urlConnection instanceof HttpURLConnection) {
+            connection = (HttpURLConnection) urlConnection;
+        }
+        assertNotNull("Connection is null", connection);
+
+        log.info(connection.getResponseCode() + " " + connection.getResponseMessage());
+
+        try {
+            in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
+        } catch (IOException ex) {
+            in = null;
+            ex.printStackTrace();
+        }
+        assertNotNull("Input stream failed", in);
+
+        String current;
+        try {
+            while ((current = in.readLine()) != null) {
+                urlContent += current;
+            }
+        } catch (IOException ex) {
+            urlContent = null;
+            ex.printStackTrace();
+        }
+        assertNotNull("Content is null", urlContent);
+        assertTrue("Content is empty", urlContent.length() > 0);
+    }
+}

core-java/src/test/java/com/baeldung/maths/FloatingPointArithmeticTest.java

@@ -0,0 +1,45 @@
+package com.baeldung.maths;
+
+import java.math.BigDecimal;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class FloatingPointArithmeticTest {
+
+    @Test
+    public void givenDecimalNumbers_whenAddedTogether_thenGetExpectedResult() {
+        double a = 13.22;
+        double b = 4.88;
+        double c = 21.45;
+        double result = 39.55;
+        
+        double abc = a + b + c;
+        double acb = a + c + b;
+        
+        Assert.assertEquals(result, abc, 0);
+        Assert.assertNotEquals(result, acb, 0);
+        
+        double ab = 18.1;
+        double ac = 34.67;
+        
+        double ab_c = ab + c;
+        double ac_b = ac + b;
+        
+        Assert.assertEquals(result, ab_c, 0);
+        Assert.assertNotEquals(result, ac_b, 0);
+        
+        BigDecimal d = new BigDecimal(String.valueOf(a));
+        BigDecimal e = new BigDecimal(String.valueOf(b));
+        BigDecimal f = new BigDecimal(String.valueOf(c));
+        BigDecimal sum = new BigDecimal("39.55");
+        
+        BigDecimal def = d.add(e).add(f);
+        BigDecimal dfe = d.add(f).add(e);
+        
+        Assert.assertEquals(0, def.compareTo(sum));
+        Assert.assertEquals(0, dfe.compareTo(sum));
+        
+        Assert.assertNotEquals(0, sum.compareTo(new BigDecimal(String.valueOf(acb))));
+    }
+}

core-java/src/test/java/com/baeldung/reflection/BaeldungReflectionUtilsTest.java

@@ -0,0 +1,24 @@
+package com.baeldung.reflection;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.Assert.assertTrue;
+
+public class BaeldungReflectionUtilsTest {
+
+    @Test
+    public void givenCustomer_whenAFieldIsNull_thenFieldNameInResult() throws Exception {
+        Customer customer = new Customer(1, "Himanshu", null, null);
+
+        List<String> result = BaeldungReflectionUtils.getNullPropertiesList(customer);
+        List<String> expectedFieldNames = Arrays.asList("emailId", "phoneNumber");
+
+        assertTrue(result.size() == expectedFieldNames.size());
+        assertTrue(result.containsAll(expectedFieldNames));
+
+    }
+
+}

core-java/src/test/java/com/baeldung/serialization/PersonUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeuldung.serialization;
+package com.baeldung.serialization;
 
 import static org.junit.Assert.assertTrue;
 

core-java/src/test/java/com/baeldung/string/StringToCharStreamUnitTest.java

@@ -0,0 +1,59 @@
+package com.baeldung.string;
+
+import org.junit.Test;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+import static org.hamcrest.CoreMatchers.instanceOf;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertThat;
+
+public class StringToCharStreamUnitTest {
+
+    private String testString = "Tests";
+
+    @Test
+    public void givenTestString_whenChars_thenReturnIntStream() {
+        assertThat(testString.chars(), instanceOf(IntStream.class));
+    }
+
+    @Test
+    public void givenTestString_whenCodePoints_thenReturnIntStream() {
+        assertThat(testString.codePoints(), instanceOf(IntStream.class));
+    }
+
+    @Test
+    public void givenTestString_whenCodePoints_thenShowOccurences() throws Exception {
+        Map<Character, Integer> map = testString.codePoints()
+          .mapToObj(c -> (char) c)
+          .filter(Character::isLetter)
+          .collect(Collectors.toMap(c -> c, c -> 1, Integer::sum));
+
+        System.out.println(map);
+    }
+
+    @Test
+    public void givenIntStream_whenMapToObj_thenReturnCharacterStream() {
+        Stream<Character> characterStream = testString.chars()
+          .mapToObj(c -> (char) c);
+        Stream<Character> characterStream1 = testString.codePoints()
+          .mapToObj(c -> (char) c);
+        assertNotNull("IntStream returned by chars() did not map to Stream<Character>", characterStream);
+        assertNotNull("IntStream returned by codePoints() did not map to Stream<Character>", characterStream1);
+    }
+
+    @Test
+    public void givenIntStream_whenMapToObj_thenReturnStringStream() {
+        List<String> strings = testString.codePoints()
+          .mapToObj(c -> String.valueOf((char) c))
+          .collect(Collectors.toList());
+
+        assertEquals(strings.size(), 5);
+    }
+
+}

core-java/src/test/java/com/baeldung/synchronousqueue/SynchronousQueueIntegrationTest.java

@@ -12,9 +12,9 @@ import java.util.concurrent.atomic.AtomicInteger;
 import static junit.framework.TestCase.assertEquals;
 
 @FixMethodOrder(MethodSorters.NAME_ASCENDING)
-public class SynchronousQueueUnitTest {
+public class SynchronousQueueIntegrationTest {
 
-    private static final Logger LOG = LoggerFactory.getLogger(SynchronousQueueUnitTest.class);
+    private static final Logger LOG = LoggerFactory.getLogger(SynchronousQueueIntegrationTest.class);
 
 
     @Test

drools/README.MD

@@ -0,0 +1,3 @@
+### Relevant Articles:
+[Introduction to Drools](http://www.baeldung.com/drools)
+[Drools Using Rules from Excel Files](http://www.baeldung.com/drools-excel)

drools/pom.xml

@@ -16,7 +16,7 @@
 
     <properties>
         <http-component-version>4.4.6</http-component-version>
-        <drools-version>7.0.0.CR1</drools-version>
+        <drools-version>7.1.0.Beta2</drools-version>
         <apache-poi-version>3.13</apache-poi-version>
     </properties>
 

drools/src/main/java/com/baeldung/drools/config/DroolsBeanFactory.java

@@ -1,10 +1,15 @@
 package com.baeldung.drools.config;
 
+import org.drools.decisiontable.DecisionTableProviderImpl;
 import org.kie.api.KieServices;
 import org.kie.api.builder.*;
 import org.kie.api.io.KieResources;
+import org.kie.api.io.Resource;
 import org.kie.api.runtime.KieContainer;
 import org.kie.api.runtime.KieSession;
+import org.kie.internal.builder.DecisionTableConfiguration;
+import org.kie.internal.builder.DecisionTableInputType;
+import org.kie.internal.builder.KnowledgeBuilderFactory;
 import org.kie.internal.io.ResourceFactory;
 import java.io.IOException;
 import java.util.Arrays;
@@ -64,4 +69,39 @@ public class DroolsBeanFactory {
 
     }
 
-}
+    public KieSession getKieSession(Resource dt) {
+        KieFileSystem kieFileSystem = kieServices.newKieFileSystem()
+            .write(dt);
+
+        KieBuilder kieBuilder = kieServices.newKieBuilder(kieFileSystem)
+            .buildAll();
+
+        KieRepository kieRepository = kieServices.getRepository();
+
+        ReleaseId krDefaultReleaseId = kieRepository.getDefaultReleaseId();
+
+        KieContainer kieContainer = kieServices.newKieContainer(krDefaultReleaseId);
+
+        KieSession ksession = kieContainer.newKieSession();
+
+        return ksession;
+    }
+
+    /*
+     * Can be used for debugging
+     * Input excelFile example: com/baeldung/drools/rules/Discount.xls
+     */
+    public String getDrlFromExcel(String excelFile) {
+        DecisionTableConfiguration configuration = KnowledgeBuilderFactory.newDecisionTableConfiguration();
+        configuration.setInputType(DecisionTableInputType.XLS);
+
+        Resource dt = ResourceFactory.newClassPathResource(excelFile, getClass());
+
+        DecisionTableProviderImpl decisionTableProvider = new DecisionTableProviderImpl();
+
+        String drl = decisionTableProvider.loadFromResource(dt, null);
+
+        return drl;
+    }
+
+}

drools/src/main/java/com/baeldung/drools/model/Customer.java

@@ -0,0 +1,44 @@
+package com.baeldung.drools.model;
+
+public class Customer {
+
+    private CustomerType type;
+
+    private int years;
+
+    private int discount;
+
+    public Customer(CustomerType type, int numOfYears) {
+        super();
+        this.type = type;
+        this.years = numOfYears;
+    }
+
+    public CustomerType getType() {
+        return type;
+    }
+
+    public void setType(CustomerType type) {
+        this.type = type;
+    }
+
+    public int getYears() {
+        return years;
+    }
+
+    public void setYears(int years) {
+        this.years = years;
+    }
+
+    public int getDiscount() {
+        return discount;
+    }
+
+    public void setDiscount(int discount) {
+        this.discount = discount;
+    }
+
+    public enum CustomerType {
+        INDIVIDUAL, BUSINESS;
+    }
+}

drools/src/test/java/com/baeldung/drools/service/ApplicantServiceIntegrationTest.java

@@ -17,37 +17,39 @@ public class ApplicantServiceIntegrationTest {
     private ApplicantService applicantService;
 
     @Before
-    public void setup(){
+    public void setup() {
         applicantService = new ApplicantService();
     }
 
     @Test
     public void whenCriteriaMatching_ThenSuggestManagerRole() throws IOException {
-        Applicant applicant=new Applicant("Davis",37,1600000.0,11);
-        SuggestedRole suggestedRole=new SuggestedRole();
-        applicantService.suggestARoleForApplicant(applicant,suggestedRole);
-        assertEquals("Manager",suggestedRole.getRole());
+        Applicant applicant = new Applicant("Davis", 37, 1600000.0, 11);
+        SuggestedRole suggestedRole = new SuggestedRole();
+        applicantService.suggestARoleForApplicant(applicant, suggestedRole);
+        assertEquals("Manager", suggestedRole.getRole());
     }
 
     @Test
     public void whenCriteriaMatching_ThenSuggestSeniorDeveloperRole() throws IOException {
-        Applicant applicant=new Applicant("John",37,1200000.0,8);
-        SuggestedRole suggestedRole=new SuggestedRole();
-        applicantService.suggestARoleForApplicant(applicant,suggestedRole);
-        assertEquals("Senior developer",suggestedRole.getRole());
+        Applicant applicant = new Applicant("John", 37, 1200000.0, 8);
+        SuggestedRole suggestedRole = new SuggestedRole();
+        applicantService.suggestARoleForApplicant(applicant, suggestedRole);
+        assertEquals("Senior developer", suggestedRole.getRole());
     }
+
     @Test
     public void whenCriteriaMatching_ThenSuggestDeveloperRole() throws IOException {
-        Applicant applicant=new Applicant("Davis",37,800000.0,3);
-        SuggestedRole suggestedRole=new SuggestedRole();
-        applicantService.suggestARoleForApplicant(applicant,suggestedRole);
-        assertEquals("Developer",suggestedRole.getRole());
+        Applicant applicant = new Applicant("Davis", 37, 800000.0, 3);
+        SuggestedRole suggestedRole = new SuggestedRole();
+        applicantService.suggestARoleForApplicant(applicant, suggestedRole);
+        assertEquals("Developer", suggestedRole.getRole());
     }
+
     @Test
     public void whenCriteriaNotMatching_ThenNoRole() throws IOException {
-        Applicant applicant=new Applicant("John",37,1200000.0,5);
-        SuggestedRole suggestedRole=new SuggestedRole();
-        applicantService.suggestARoleForApplicant(applicant,suggestedRole);
+        Applicant applicant = new Applicant("John", 37, 1200000.0, 5);
+        SuggestedRole suggestedRole = new SuggestedRole();
+        applicantService.suggestARoleForApplicant(applicant, suggestedRole);
         assertNull(suggestedRole.getRole());
     }
 }

drools/src/test/java/com/baeldung/drools/service/DiscountExcelIntegrationTest.java

@@ -0,0 +1,56 @@
+package com.baeldung.drools.service;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.kie.api.io.Resource;
+import org.kie.api.runtime.KieSession;
+import org.kie.internal.io.ResourceFactory;
+
+import com.baeldung.drools.config.DroolsBeanFactory;
+import com.baeldung.drools.model.Customer;
+import com.baeldung.drools.model.Customer.CustomerType;
+
+public class DiscountExcelIntegrationTest {
+
+    private KieSession kSession;
+
+    @Before
+    public void setup() {
+        Resource resource = ResourceFactory.newClassPathResource("com/baeldung/drools/rules/Discount.xls", getClass());
+        kSession = new DroolsBeanFactory().getKieSession(resource);
+    }
+
+    @Test
+    public void giveIndvidualLongStanding_whenFireRule_thenCorrectDiscount() throws Exception {
+        Customer customer = new Customer(CustomerType.INDIVIDUAL, 5);
+        kSession.insert(customer);
+
+        kSession.fireAllRules();
+
+        assertEquals(customer.getDiscount(), 15);
+    }
+
+    @Test
+    public void giveIndvidualRecent_whenFireRule_thenCorrectDiscount() throws Exception {
+
+        Customer customer = new Customer(CustomerType.INDIVIDUAL, 1);
+        kSession.insert(customer);
+
+        kSession.fireAllRules();
+
+        assertEquals(customer.getDiscount(), 5);
+    }
+
+    @Test
+    public void giveBusinessAny_whenFireRule_thenCorrectDiscount() throws Exception {
+        Customer customer = new Customer(CustomerType.BUSINESS, 0);
+        kSession.insert(customer);
+
+        kSession.fireAllRules();
+
+        assertEquals(customer.getDiscount(), 20);
+    }
+
+}

drools/src/test/java/com/baeldung/drools/service/ProductServiceIntegrationTest.java

@@ -3,6 +3,7 @@ package com.baeldung.drools.service;
 import com.baeldung.drools.model.Product;
 import org.junit.Before;
 import org.junit.Test;
+
 import static junit.framework.TestCase.assertEquals;
 
 
@@ -11,22 +12,22 @@ public class ProductServiceIntegrationTest {
     private ProductService productService;
 
     @Before
-    public void setup(){
-        productService=new ProductService();
+    public void setup() {
+        productService = new ProductService();
     }
 
 
     @Test
-    public void whenProductTypeElectronic_ThenLabelBarcode(){
-        Product product=new Product("Microwave","Electronic");
-        product=productService.applyLabelToProduct(product);
-        assertEquals("BarCode",product.getLabel());
+    public void whenProductTypeElectronic_ThenLabelBarcode() {
+        Product product = new Product("Microwave", "Electronic");
+        product = productService.applyLabelToProduct(product);
+        assertEquals("BarCode", product.getLabel());
     }
 
     @Test
-    public void whenProductTypeBook_ThenLabelIsbn(){
-        Product product=new Product("AutoBiography","Book");
-        product=productService.applyLabelToProduct(product);
-        assertEquals("ISBN",product.getLabel());
+    public void whenProductTypeBook_ThenLabelIsbn() {
+        Product product = new Product("AutoBiography", "Book");
+        product = productService.applyLabelToProduct(product);
+        assertEquals("ISBN", product.getLabel());
     }
 }

guava/README.md

@@ -25,3 +25,6 @@
 - [Guide to Guava RangeMap](http://www.baeldung.com/guava-rangemap)
 - [Guide to Guava Table](http://www.baeldung.com/guava-table)
 - [Guide to Guava’s Reflection Utilities](http://www.baeldung.com/guava-reflection)
+- [Guide to Guava ClassToInstanceMap](http://www.baeldung.com/guava-class-to-instance-map)
+- [Guide to Guava MinMaxPriorityQueue and EvictingQueue](http://www.baeldung.com/guava-minmax-priority-queue-and-evicting-queue)
+- [Guide to Mathematical Utilities in Guava](http://www.baeldung.com/guava-math)

guest/junit5-example/.gitignore

@@ -0,0 +1,4 @@
+/target/
+.settings/
+.classpath
+.project

guest/junit5-example/pom.xml

@@ -0,0 +1,68 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>junit5-example</groupId>
+	<artifactId>junit5-example</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.junit.jupiter</groupId>
+			<artifactId>junit-jupiter-engine</artifactId>
+			<version>5.0.0-M4</version>
+		</dependency>
+		<dependency>
+			<groupId>org.junit.jupiter</groupId>
+			<artifactId>junit-jupiter-params</artifactId>
+			<version>5.0.0-M4</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.junit.vintage</groupId>
+			<artifactId>junit-vintage-engine</artifactId>
+			<version>4.12.0-M4</version>
+		</dependency>
+
+		<dependency>
+			<groupId>com.h2database</groupId>
+			<artifactId>h2</artifactId>
+			<version>1.4.195</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.logging.log4j</groupId>
+			<artifactId>log4j-core</artifactId>
+			<version>2.8.2</version>
+		</dependency>
+
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.5</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+				</configuration>
+			</plugin>
+			<plugin>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<version>2.19.1</version>
+				<dependencies>
+					<dependency>
+						<groupId>org.junit.platform</groupId>
+						<artifactId>junit-platform-surefire-provider</artifactId>
+						<version>1.0.0-M4</version>
+					</dependency>
+				</dependencies>
+				<configuration>
+					<properties>
+						<excludeTags>math</excludeTags>
+					</properties>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+</project>

guest/junit5-example/src/main/java/com/stackify/daos/UserDAO.java

@@ -0,0 +1,141 @@
+package com.stackify.daos;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import com.stackify.models.User;
+import com.stackify.utils.ConnectionUtil;
+
+public class UserDAO {
+
+    private Logger logger = LogManager.getLogger(UserDAO.class);
+
+    public void createTable() {
+        try (Connection con = ConnectionUtil.getConnection()) {
+            String createQuery = "CREATE TABLE users(email varchar(50) primary key, name varchar(50))";
+            PreparedStatement pstmt = con.prepareStatement(createQuery);
+
+            pstmt.execute();
+        } catch (SQLException exc) {
+            logger.error(exc.getMessage());
+        }
+
+    }
+
+    public void add(User user) {
+        try (Connection con = ConnectionUtil.getConnection()) {
+
+            String insertQuery = "INSERT INTO users(email,name) VALUES(?,?)";
+            PreparedStatement pstmt = con.prepareStatement(insertQuery);
+            pstmt.setString(1, user.getEmail());
+            pstmt.setString(2, user.getName());
+
+            pstmt.executeUpdate();
+        } catch (SQLException exc) {
+            logger.error(exc.getMessage());
+        }
+    }
+
+    public void update(User user) {
+        try (Connection con = ConnectionUtil.getConnection()) {
+
+            String updateQuery = "UPDATE users SET name=? WHERE email=?";
+            PreparedStatement pstmt = con.prepareStatement(updateQuery);
+            pstmt.setString(1, user.getName());
+            pstmt.setString(2, user.getEmail());
+
+            pstmt.executeUpdate();
+        } catch (SQLException exc) {
+            logger.error(exc.getMessage());
+        }
+    }
+
+    public void delete(User user) {
+        try (Connection con = ConnectionUtil.getConnection()) {
+
+            String deleteQuery = "DELETE FROM users WHERE email=?";
+            PreparedStatement pstmt = con.prepareStatement(deleteQuery);
+            pstmt.setString(1, user.getEmail());
+
+            pstmt.executeUpdate();
+        } catch (SQLException exc) {
+            logger.error(exc.getMessage());
+        }
+    }
+
+    public void delete(String email) {
+        try (Connection con = ConnectionUtil.getConnection()) {
+
+            String deleteQuery = "DELETE FROM users WHERE email=?";
+            PreparedStatement pstmt = con.prepareStatement(deleteQuery);
+            pstmt.setString(1, email);
+
+            pstmt.executeUpdate();
+        } catch (SQLException exc) {
+            logger.error(exc.getMessage());
+        }
+    }
+
+    public User findOne(String email) {
+        User user = null;
+
+        try (Connection con = ConnectionUtil.getConnection()) {
+            String query = "SELECT * FROM users WHERE email=?";
+            PreparedStatement pstmt = con.prepareStatement(query);
+            pstmt.setString(1, email);
+
+            ResultSet rs = pstmt.executeQuery();
+            while (rs.next()) {
+                user = new User();
+                user.setEmail(rs.getString("email"));
+                user.setName(rs.getString("name"));
+            }
+
+        } catch (SQLException exc) {
+            logger.error(exc.getMessage());
+        }
+
+        return user;
+    }
+
+    public List<User> findAll() {
+        List<User> users = new ArrayList<>();
+
+        try (Connection con = ConnectionUtil.getConnection()) {
+            String query = "SELECT * FROM users";
+            PreparedStatement pstmt = con.prepareStatement(query);
+
+            ResultSet rs = pstmt.executeQuery();
+            while (rs.next()) {
+                User user = new User();
+                user.setEmail(rs.getString("email"));
+                user.setName(rs.getString("name"));
+                users.add(user);
+            }
+        } catch (SQLException exc) {
+            logger.error(exc.getMessage());
+        }
+
+        return users;
+    }
+
+    public void deleteAll() {
+        try (Connection con = ConnectionUtil.getConnection()) {
+
+            String deleteQuery = "DELETE FROM users";
+            PreparedStatement pstmt = con.prepareStatement(deleteQuery);
+
+            pstmt.executeUpdate();
+        } catch (SQLException exc) {
+            logger.error(exc.getMessage());
+        }
+    }
+
+}

guest/junit5-example/src/main/java/com/stackify/models/User.java

@@ -0,0 +1,63 @@
+package com.stackify.models;
+
+public class User {
+    private String email;
+    private String name;
+
+    public User() {
+    }
+
+    public User(String email, String name) {
+        super();
+        this.email = email;
+        this.name = name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((email == null) ? 0 : email.hashCode());
+        result = prime * result + ((name == null) ? 0 : name.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        User other = (User) obj;
+        if (email == null) {
+            if (other.email != null)
+                return false;
+        } else if (!email.equals(other.email))
+            return false;
+        if (name == null) {
+            if (other.name != null)
+                return false;
+        } else if (!name.equals(other.name))
+            return false;
+        return true;
+    }
+
+}

guest/junit5-example/src/main/java/com/stackify/test/conditions/DisabledOnEnvironment.java

@@ -0,0 +1,15 @@
+package com.stackify.test.conditions;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.jupiter.api.extension.ExtendWith;
+
+@Target({ ElementType.METHOD })
+@Retention(RetentionPolicy.RUNTIME)
+@ExtendWith(DisabledOnEnvironmentCondition.class)
+public @interface DisabledOnEnvironment {
+    String[] value();
+}

guest/junit5-example/src/main/java/com/stackify/test/conditions/DisabledOnEnvironmentCondition.java

@@ -0,0 +1,38 @@
+package com.stackify.test.conditions;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Optional;
+import java.util.Properties;
+
+import org.junit.jupiter.api.extension.ConditionEvaluationResult;
+import org.junit.jupiter.api.extension.TestExecutionCondition;
+import org.junit.jupiter.api.extension.TestExtensionContext;
+import org.junit.platform.commons.support.AnnotationSupport;
+
+import com.stackify.utils.ConnectionUtil;
+
+public class DisabledOnEnvironmentCondition implements TestExecutionCondition {
+
+    @Override
+    public ConditionEvaluationResult evaluate(TestExtensionContext context) {
+        Properties props = new Properties();
+        String env = "";
+        try {
+            props.load(ConnectionUtil.class.getResourceAsStream("/application.properties"));
+            env = props.getProperty("env");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        Optional<DisabledOnEnvironment> disabled = AnnotationSupport.findAnnotation(context.getElement().get(), DisabledOnEnvironment.class);
+        if (disabled.isPresent()) {
+            String[] envs = disabled.get().value();
+            if (Arrays.asList(envs).contains(env)) {
+                return ConditionEvaluationResult.disabled("Disabled on environment " + env);
+            }
+        }
+
+        return ConditionEvaluationResult.enabled("Enabled on environment "+env);
+    }
+
+}

guest/junit5-example/src/main/java/com/stackify/utils/ConnectionUtil.java

@@ -0,0 +1,38 @@
+package com.stackify.utils;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.util.Properties;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+public class ConnectionUtil {
+
+    private static Logger logger = LogManager.getLogger(ConnectionUtil.class);
+
+    public static Connection getConnection() {
+        try {
+            Properties props = new Properties();
+            props.load(ConnectionUtil.class.getResourceAsStream("jdbc.properties"));
+            Class.forName(props.getProperty("jdbc.driver"));
+            Connection con = DriverManager.getConnection(props.getProperty("jdbc.url"), props.getProperty("jdbc.user"), props.getProperty("jdbc.password"));
+            return con;
+        }
+
+        catch (FileNotFoundException exc) {
+            logger.error(exc.getMessage());
+        } catch (IOException exc) {
+            logger.error(exc.getMessage());
+        } catch (ClassNotFoundException exc) {
+            logger.error(exc.getMessage());
+        } catch (SQLException exc) {
+            logger.error(exc.getMessage());
+        }
+        return null;
+    }
+
+}

guest/junit5-example/src/main/resources/application.properties

@@ -0,0 +1 @@
+env=dev

guest/junit5-example/src/main/resources/com/stackify/utils/jdbc.properties

@@ -0,0 +1,4 @@
+jdbc.driver=org.h2.Driver
+jdbc.url=jdbc:h2:mem:myDb;DB_CLOSE_DELAY=-1
+jdbc.user=
+jdbc.password=

guest/junit5-example/src/main/resources/log4j2.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Configuration status="WARN">
+  <Appenders>
+    <Console name="Console" target="SYSTEM_OUT">
+      <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
+    </Console>
+  </Appenders>
+  <Loggers>
+    <Root level="info">
+      <AppenderRef ref="Console"/>
+    </Root>
+  </Loggers>
+</Configuration>

guest/junit5-example/src/test/java/com/stackify/test/DatabaseConnectionTest.java

@@ -0,0 +1,19 @@
+package com.stackify.test;
+
+import java.sql.Connection;
+
+import org.junit.jupiter.api.Test;
+
+import com.stackify.utils.ConnectionUtil;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public interface DatabaseConnectionTest {
+
+    @Test
+    default void testDatabaseConnection() {
+        Connection con = ConnectionUtil.getConnection();
+        assertNotNull(con);
+    }
+
+}

guest/junit5-example/src/test/java/com/stackify/test/DynamicTests.java

@@ -0,0 +1,38 @@
+package com.stackify.test;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.*;
+import org.junit.jupiter.api.DynamicTest;
+import org.junit.jupiter.api.TestFactory;
+import org.junit.jupiter.api.function.ThrowingConsumer;
+
+import com.stackify.daos.UserDAO;
+import com.stackify.models.User;
+
+public class DynamicTests {
+    
+    @TestFactory
+    public Collection<DynamicTest> dynamicTestCollection() {
+        return Arrays.asList(DynamicTest.dynamicTest("Dynamic Test", () -> assertTrue(1 == 1)));
+    }
+
+    @TestFactory
+    public Stream<DynamicTest> dynamicUserTestCollection() {
+        List<User> inputList = Arrays.asList(new User("john@yahoo.com", "John"), new User("ana@yahoo.com", "Ana"));
+
+        Function<User, String> displayNameGenerator = (input) -> "Saving user: " + input;
+
+        UserDAO userDAO = new UserDAO();
+        ThrowingConsumer<User> testExecutor = (input) -> {
+            userDAO.add(input);
+            assertNotNull(userDAO.findOne(input.getEmail()));
+        };
+
+        return DynamicTest.stream(inputList.iterator(), displayNameGenerator, testExecutor);
+    }
+}

guest/junit5-example/src/test/java/com/stackify/test/IncrementTest.java

@@ -0,0 +1,25 @@
+package com.stackify.test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.RepeatedTest;
+import org.junit.jupiter.api.RepetitionInfo;
+
+public class IncrementTest {
+    
+    private static Logger logger = LogManager.getLogger(IncrementTest.class);
+
+    @BeforeEach
+    public void increment() {
+        logger.info("Before Each Test");
+    }
+
+    @RepeatedTest(value = 3, name = RepeatedTest.SHORT_DISPLAY_NAME)
+    public void test(RepetitionInfo info) {
+        assertTrue(1 == 1);
+        logger.info("Repetition #" + info.getCurrentRepetition());
+    }
+}

guest/junit5-example/src/test/java/com/stackify/test/TaggedTest.java

@@ -0,0 +1,16 @@
+package com.stackify.test;
+
+import static org.junit.jupiter.api.Assertions.*;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+
+@Tag("math")
+public class TaggedTest {
+
+    @Test
+    @Tag("arithmetic")
+    public void testEquals() {
+        assertTrue(1 == 1);
+    }
+
+}

guest/junit5-example/src/test/java/com/stackify/test/UsersTest.java

@@ -0,0 +1,155 @@
+package com.stackify.test;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInfo;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assumptions.*;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import com.stackify.daos.UserDAO;
+import com.stackify.models.User;
+
+import com.stackify.test.conditions.DisabledOnEnvironment;
+
+public class UsersTest implements DatabaseConnectionTest {
+
+    private static UserDAO userDAO;
+
+    private static Logger logger = LogManager.getLogger(UsersTest.class);
+
+    @BeforeAll
+    public static void addData() {
+        userDAO = new UserDAO();
+        userDAO.createTable();
+
+        User user1 = new User("john@gmail.com", "John");
+        User user2 = new User("ana@gmail.com", "Ana");
+        userDAO.add(user1);
+        userDAO.add(user2);
+    }
+
+    @Test
+    @DisplayName("Test Get Users")
+    public void testGetUsersNumber() {
+        assertEquals(2, userDAO.findAll().size());
+
+    }
+
+    @Test
+    @DisplayName("Test Get Users")
+    public void testGetUsersNumberWithInfo(TestInfo testInfo) {
+        assertEquals(2, userDAO.findAll().size());
+        assertEquals("Test Get Users", testInfo.getDisplayName());
+        assertEquals(UsersTest.class, testInfo.getTestClass().get());
+        logger.info("Running test method:" + testInfo.getTestMethod().get().getName());
+    }
+
+    @Test
+    public void testGetUser() {
+        User user = userDAO.findOne("john@gmail.com");
+        assertEquals("John", user.getName(), "User name:" + user.getName() + " incorrect");
+    }
+
+    @Test
+    public void testClassicAssertions() {
+        User user1 = userDAO.findOne("john@gmail.com");
+        User user2 = userDAO.findOne("john@yahoo.com");
+
+        assertNotNull(user1);
+        assertNull(user2);
+
+        user2 = new User("john@yahoo.com", "John");
+        assertEquals(user1.getName(), user2.getName(), "Names are not equal");
+        assertFalse(user1.getEmail().equals(user2.getEmail()), "Emails are equal");
+        assertNotSame(user1, user2);
+    }
+
+    @Test
+    @Disabled
+    public void testGroupedAssertions() {
+        User user = userDAO.findOne("john@gmail.com");
+        assertAll("user", () -> assertEquals("Johnson", user.getName()), () -> assertEquals("johnson@gmail.com", user.getEmail()));
+    }
+
+    @Test
+    public void testIterableEquals() {
+        User user1 = new User("john@gmail.com", "John");
+        User user2 = new User("ana@gmail.com", "Ana");
+
+        List<User> users = new ArrayList<>();
+        users.add(user1);
+        users.add(user2);
+
+        assertIterableEquals(users, userDAO.findAll());
+    }
+
+    @Test
+    public void testLinesMatch() {
+        List<String> expectedLines = Collections.singletonList("(.*)@(.*)");
+        List<String> emails = Arrays.asList("john@gmail.com");
+        assertLinesMatch(expectedLines, emails);
+    }
+
+    @Test
+    void testThrows() {
+        User user = null;
+        Exception exception = assertThrows(NullPointerException.class, () -> user.getName());
+        logger.info(exception.getMessage());
+    }
+
+    @Test
+    @DisabledOnEnvironment({ "dev", "prod")
+    void testFail() {
+        fail("this test fails");
+    }
+
+    @Test
+    void testAssumptions() {
+        List<User> users = userDAO.findAll();
+        assumeFalse(users == null);
+        assumeTrue(users.size() > 0);
+
+        User user1 = new User("john@gmail.com", "John");
+
+        assumingThat(users.contains(user1), () -> assertTrue(users.size() > 1));
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = { "john@gmail.com", "ana@gmail.com" })
+    public void testParameterized(String email) {
+        assertNotNull(userDAO.findOne(email));
+    }
+
+    @AfterAll
+    public static void removeData() {
+        userDAO.deleteAll();
+    }
+
+    @Nested
+    class DeleteUsersTest {
+        @Test
+        public void addUser() {
+            User user = new User("bob@gmail.com", "Bob");
+            userDAO.add(user);
+            assertNotNull(userDAO.findOne("bob@gmail.com"));
+
+            userDAO.delete("bob@gmail.com");
+            assertNull(userDAO.findOne("bob@gmail.com"));
+        }
+    }
+
+}

guest/memory-leaks/pom.xml

@@ -0,0 +1,39 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.baeldung</groupId>
+	<artifactId>memory-leaks</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+
+	<dependencies>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>4.12</version>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<resources>
+			<resource>
+				<directory>src/main/resources/</directory>
+				<excludes>
+					<exclude>**/*.java</exclude>
+				</excludes>
+			</resource>
+			<resource>
+				<directory>src/test/resources/</directory>
+			</resource>
+		</resources>
+		<plugins>
+			<plugin>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.5</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+</project>

guest/memory-leaks/src/test/java/com/baeldung/Key.java

@@ -0,0 +1,11 @@
+package com.baeldung;
+
+public class Key {
+
+    public static String key;
+
+    public Key(String key) {
+        Key.key = key;
+    }
+
+}

guest/memory-leaks/src/test/java/com/baeldung/MemoryLeaksTest.java

@@ -0,0 +1,86 @@
+//package com.baeldung;
+//
+//import java.io.BufferedReader;
+//import java.io.File;
+//import java.io.IOException;
+//import java.io.InputStream;
+//import java.io.InputStreamReader;
+//import java.net.URISyntaxException;
+//import java.net.URL;
+//import java.net.URLConnection;
+//import java.nio.charset.StandardCharsets;
+//import java.nio.file.Files;
+//import java.nio.file.Paths;
+//import java.nio.file.StandardOpenOption;
+//import java.util.ArrayList;
+//import java.util.Map;
+//import java.util.Random;
+//import java.util.Scanner;
+//
+//import org.junit.FixMethodOrder;
+//import org.junit.Test;
+//import org.junit.runner.RunWith;
+//import org.junit.runners.JUnit4;
+//import org.junit.runners.MethodSorters;
+//
+//@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+//@RunWith(JUnit4.class)
+//public class MemoryLeaksTest {
+
+//    private Random random = new Random();
+//    public static final ArrayList<Double> list = new ArrayList<Double>(1000000);
+//
+//    @Test(expected = OutOfMemoryError.class)
+//    public void givenStaticField_whenLotsOfOperations_thenMemoryLeak() throws InterruptedException {
+//        while (true) {
+//            int k = random.nextInt(100000);
+//            System.out.println(k);
+//            Thread.sleep(10000); //to allow GC do its job
+//            for (int i = 0; i < k; i++) {
+//                list.add(random.nextDouble());
+//            }
+//        }
+//
+//    }
+//
+//    @SuppressWarnings({ "resource" })
+//    @Test(expected = OutOfMemoryError.class)
+//    public void givenLengthString_whenIntern_thenOutOfMemory() throws IOException {
+//        String str = new Scanner(new File("src/test/resources/large.txt"), "UTF-8").useDelimiter("\\A")
+//            .next();
+//        str.intern();
+//        System.out.println("Done");
+//    }
+
+//    @Test(expected = OutOfMemoryError.class)
+//    public void givenURL_whenUnclosedStream_thenOutOfMemory() throws IOException, URISyntaxException {
+//        String str = "";
+//        URLConnection conn = new URL("http://norvig.com/big.txt").openConnection();
+//        BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8));
+//        while (br.readLine() != null) {
+//            str += br.readLine();
+//        }
+//        Files.write(Paths.get("src/main/resources/"), str.getBytes(), StandardOpenOption.CREATE);
+//    }
+//
+//    @SuppressWarnings("unused")
+//    @Test(expected = OutOfMemoryError.class)
+//    public void givenConnection_whenUnclosed_thenOutOfMemory() throws IOException, URISyntaxException {
+//        URL url = new URL("ftp://speedtest.tele2.net");
+//        URLConnection urlc = url.openConnection();
+//        InputStream is = urlc.getInputStream();
+//        String str = "";
+//        while (true) {
+//            str += is.toString()
+//                .intern();
+//        }
+//    }
+//
+//    @Test(expected = OutOfMemoryError.class)
+//    public void givenMap_whenNoEqualsNoHashCodeMethods_thenOutOfMemory() throws IOException, URISyntaxException {
+//        Map<Object, Object> map = System.getProperties();
+//        while (true) {
+//            map.put(new Key("key"), "value");
+//        }
+//    }
+//}

guest/webservices/rest-client/WebContent/META-INF/MANIFEST.MF

@@ -0,0 +1,3 @@
+Manifest-Version: 1.0
+Class-Path: 
+

guest/webservices/rest-client/pom.xml

@@ -0,0 +1,27 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.stackify</groupId>
+  <artifactId>rest-client</artifactId>
+  <version>0.0.1-SNAPSHOT</version>
+  <packaging>war</packaging>
+  <build>
+    <plugins>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.5</version>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
+      <plugin>
+        <artifactId>maven-war-plugin</artifactId>
+        <version>2.6</version>
+        <configuration>
+          <warSourceDirectory>WebContent</warSourceDirectory>
+          <failOnMissingWebXml>false</failOnMissingWebXml>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

guest/webservices/rest-client/rest-client/.angular-cli.json

@@ -0,0 +1,57 @@
+{
+  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
+  "project": {
+    "name": "rest-client"
+  },
+  "apps": [
+    {
+      "root": "src",
+      "outDir": "dist",
+      "assets": [
+        "assets",
+        "favicon.ico"
+      ],
+      "index": "index.html",
+      "main": "main.ts",
+      "polyfills": "polyfills.ts",
+      "test": "test.ts",
+      "tsconfig": "tsconfig.app.json",
+      "testTsconfig": "tsconfig.spec.json",
+      "prefix": "app",
+      "styles": [
+        "styles.css"
+      ],
+      "scripts": [],
+      "environmentSource": "environments/environment.ts",
+      "environments": {
+        "dev": "environments/environment.ts",
+        "prod": "environments/environment.prod.ts"
+      }
+    }
+  ],
+  "e2e": {
+    "protractor": {
+      "config": "./protractor.conf.js"
+    }
+  },
+  "lint": [
+    {
+      "project": "src/tsconfig.app.json"
+    },
+    {
+      "project": "src/tsconfig.spec.json"
+    },
+    {
+      "project": "e2e/tsconfig.e2e.json"
+    }
+  ],
+  "test": {
+    "karma": {
+      "config": "./karma.conf.js"
+    }
+  },
+  "defaults": {
+    "styleExt": "css",
+    "component": {}
+  }
+}

guest/webservices/rest-client/rest-client/.editorconfig

@@ -0,0 +1,13 @@
+# Editor configuration, see http://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.md]
+max_line_length = off
+trim_trailing_whitespace = false

guest/webservices/rest-client/rest-client/.gitignore

@@ -0,0 +1,42 @@
+# See http://help.github.com/ignore-files/ for more about ignoring files.
+
+# compiled output
+/dist
+/tmp
+/out-tsc
+
+# dependencies
+/node_modules
+
+# IDEs and editors
+/.idea
+.project
+.classpath
+.c9/
+*.launch
+.settings/
+*.sublime-workspace
+
+# IDE - VSCode
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+
+# misc
+/.sass-cache
+/connect.lock
+/coverage
+/libpeerconnection.log
+npm-debug.log
+testem.log
+/typings
+
+# e2e
+/e2e/*.js
+/e2e/*.map
+
+# System Files
+.DS_Store
+Thumbs.db

guest/webservices/rest-client/rest-client/README.md

@@ -0,0 +1,28 @@
+# RestClient
+
+This project was generated with [Angular CLI](https://github.com/angular/angular-cli) version 1.1.3.
+
+## Development server
+
+Run `ng serve` for a dev server. Navigate to `http://localhost:4200/`. The app will automatically reload if you change any of the source files.
+
+## Code scaffolding
+
+Run `ng generate component component-name` to generate a new component. You can also use `ng generate directive|pipe|service|class|module`.
+
+## Build
+
+Run `ng build` to build the project. The build artifacts will be stored in the `dist/` directory. Use the `-prod` flag for a production build.
+
+## Running unit tests
+
+Run `ng test` to execute the unit tests via [Karma](https://karma-runner.github.io).
+
+## Running end-to-end tests
+
+Run `ng e2e` to execute the end-to-end tests via [Protractor](http://www.protractortest.org/).
+Before running the tests make sure you are serving the app via `ng serve`.
+
+## Further help
+
+To get more help on the Angular CLI use `ng help` or go check out the [Angular CLI README](https://github.com/angular/angular-cli/blob/master/README.md).

guest/webservices/rest-client/rest-client/e2e/app.e2e-spec.ts

@@ -0,0 +1,14 @@
+import { RestClientPage } from './app.po';
+
+describe('rest-client App', () => {
+  let page: RestClientPage;
+
+  beforeEach(() => {
+    page = new RestClientPage();
+  });
+
+  it('should display welcome message', () => {
+    page.navigateTo();
+    expect(page.getParagraphText()).toEqual('Welcome to app!!');
+  });
+});

guest/webservices/rest-client/rest-client/e2e/app.po.ts

@@ -0,0 +1,11 @@
+import { browser, by, element } from 'protractor';
+
+export class RestClientPage {
+  navigateTo() {
+    return browser.get('/');
+  }
+
+  getParagraphText() {
+    return element(by.css('app-root h1')).getText();
+  }
+}

guest/webservices/rest-client/rest-client/e2e/tsconfig.e2e.json

@@ -0,0 +1,12 @@
+{
+  "extends": "../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../out-tsc/e2e",
+    "module": "commonjs",
+    "target": "es5",
+    "types": [
+      "jasmine",
+      "node"
+    ]
+  }
+}

guest/webservices/rest-client/rest-client/karma.conf.js

@@ -0,0 +1,33 @@
+// Karma configuration file, see link for more information
+// https://karma-runner.github.io/0.13/config/configuration-file.html
+
+module.exports = function (config) {
+  config.set({
+    basePath: '',
+    frameworks: ['jasmine', '@angular/cli'],
+    plugins: [
+      require('karma-jasmine'),
+      require('karma-chrome-launcher'),
+      require('karma-jasmine-html-reporter'),
+      require('karma-coverage-istanbul-reporter'),
+      require('@angular/cli/plugins/karma')
+    ],
+    client:{
+      clearContext: false // leave Jasmine Spec Runner output visible in browser
+    },
+    coverageIstanbulReporter: {
+      reports: [ 'html', 'lcovonly' ],
+      fixWebpackSourcePaths: true
+    },
+    angularCli: {
+      environment: 'dev'
+    },
+    reporters: ['progress', 'kjhtml'],
+    port: 9876,
+    colors: true,
+    logLevel: config.LOG_INFO,
+    autoWatch: true,
+    browsers: ['Chrome'],
+    singleRun: false
+  });
+};

guest/webservices/rest-client/rest-client/package.json

@@ -0,0 +1,48 @@
+{
+  "name": "rest-client",
+  "version": "0.0.0",
+  "license": "MIT",
+  "scripts": {
+    "ng": "ng",
+    "start": "ng serve",
+    "build": "ng build",
+    "test": "ng test",
+    "lint": "ng lint",
+    "e2e": "ng e2e"
+  },
+  "private": true,
+  "dependencies": {
+    "@angular/animations": "^4.0.0",
+    "@angular/common": "^4.0.0",
+    "@angular/compiler": "^4.0.0",
+    "@angular/core": "^4.0.0",
+    "@angular/forms": "^4.0.0",
+    "@angular/http": "^4.0.0",
+    "@angular/platform-browser": "^4.0.0",
+    "@angular/platform-browser-dynamic": "^4.0.0",
+    "@angular/router": "^4.0.0",
+    "core-js": "^2.4.1",
+    "rxjs": "^5.1.0",
+    "zone.js": "^0.8.4"
+  },
+  "devDependencies": {
+    "@angular/cli": "1.1.3",
+    "@angular/compiler-cli": "^4.0.0",
+    "@angular/language-service": "^4.0.0",
+    "@types/jasmine": "2.5.45",
+    "@types/node": "~6.0.60",
+    "codelyzer": "~3.0.1",
+    "jasmine-core": "~2.6.2",
+    "jasmine-spec-reporter": "~4.1.0",
+    "karma": "~1.7.0",
+    "karma-chrome-launcher": "~2.1.1",
+    "karma-cli": "~1.0.1",
+    "karma-coverage-istanbul-reporter": "^1.2.1",
+    "karma-jasmine": "~1.1.0",
+    "karma-jasmine-html-reporter": "^0.2.2",
+    "protractor": "~5.1.2",
+    "ts-node": "~3.0.4",
+    "tslint": "~5.3.2",
+    "typescript": "~2.3.3"
+  }
+}

guest/webservices/rest-client/rest-client/protractor.conf.js

@@ -0,0 +1,28 @@
+// Protractor configuration file, see link for more information
+// https://github.com/angular/protractor/blob/master/lib/config.ts
+
+const { SpecReporter } = require('jasmine-spec-reporter');
+
+exports.config = {
+  allScriptsTimeout: 11000,
+  specs: [
+    './e2e/**/*.e2e-spec.ts'
+  ],
+  capabilities: {
+    'browserName': 'chrome'
+  },
+  directConnect: true,
+  baseUrl: 'http://localhost:4200/',
+  framework: 'jasmine',
+  jasmineNodeOpts: {
+    showColors: true,
+    defaultTimeoutInterval: 30000,
+    print: function() {}
+  },
+  onPrepare() {
+    require('ts-node').register({
+      project: 'e2e/tsconfig.e2e.json'
+    });
+    jasmine.getEnv().addReporter(new SpecReporter({ spec: { displayStacktrace: true } }));
+  }
+};

guest/webservices/rest-client/rest-client/src/app/app.component.html

@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Angular QuickStart</title>
+    <base href="/">
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+  </head>
+
+  <body>
+    <users-page>loading users component</users-page>
+  </body>
+</html>

guest/webservices/rest-client/rest-client/src/app/app.component.spec.ts

@@ -0,0 +1,32 @@
+import { TestBed, async } from '@angular/core/testing';
+
+import { AppComponent } from './app.component';
+
+describe('AppComponent', () => {
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      declarations: [
+        AppComponent
+      ],
+    }).compileComponents();
+  }));
+
+  it('should create the app', async(() => {
+    const fixture = TestBed.createComponent(AppComponent);
+    const app = fixture.debugElement.componentInstance;
+    expect(app).toBeTruthy();
+  }));
+
+  it(`should have as title 'app'`, async(() => {
+    const fixture = TestBed.createComponent(AppComponent);
+    const app = fixture.debugElement.componentInstance;
+    expect(app.title).toEqual('app');
+  }));
+
+  it('should render title in a h1 tag', async(() => {
+    const fixture = TestBed.createComponent(AppComponent);
+    fixture.detectChanges();
+    const compiled = fixture.debugElement.nativeElement;
+    expect(compiled.querySelector('h1').textContent).toContain('Welcome to app!!');
+  }));
+});

guest/webservices/rest-client/rest-client/src/app/app.component.ts

@@ -0,0 +1,10 @@
+import { Component } from '@angular/core';
+
+@Component({
+  selector: 'app-root',
+  templateUrl: './app.component.html',
+  styleUrls: ['./app.component.css']
+})
+export class AppComponent {
+  title = 'app';
+}

guest/webservices/rest-client/rest-client/src/app/app.module.ts

@@ -0,0 +1,25 @@
+import { BrowserModule } from '@angular/platform-browser';
+import { NgModule } from '@angular/core';
+import { HttpModule } from '@angular/http';
+import { FormsModule } from '@angular/forms';
+
+import { AppComponent } from './app.component';
+import { UsersComponent } from './users.component';
+import { RouterModule }   from '@angular/router';
+
+@NgModule({
+  declarations: [
+    AppComponent,
+    UsersComponent
+  ],
+  imports: [
+    BrowserModule,
+    HttpModule,
+	FormsModule,
+    RouterModule.forRoot([
+      { path: '', component: AppComponent },
+      { path: 'users', component: UsersComponent }])],
+  providers: [],
+  bootstrap: [AppComponent]
+})
+export class AppModule { }

guest/webservices/rest-client/rest-client/src/app/app.service.ts

@@ -0,0 +1,36 @@
+import {Injectable} from '@angular/core';
+import { Http, Response, Headers, RequestOptions } from '@angular/http';
+import 'rxjs/add/operator/map';
+
+export class User {
+  constructor(
+    public email: string,
+    public name: string) { }
+} 
+ 
+@Injectable()
+export class UserService {
+  constructor(
+    private _http: Http){}
+    
+    url = 'http://localhost:8080/rest-server/users';
+	
+    addUser(user){   
+      let headers = new Headers({'Content-Type': 'application/json'});
+      let options = new RequestOptions({ headers: headers});
+     
+      return this._http.post(this.url, JSON.stringify(user), options)
+        .map( 
+		  (_response: Response) => {
+            return _response;
+		  },
+          err => alert('Error adding user')); 
+    }
+    
+    getUsers() {
+      return this._http.get(this.url)
+        .map((_response: Response) => {
+          return _response.json();
+        });
+    }    
+}

guest/webservices/rest-client/rest-client/src/app/users.component.html

@@ -0,0 +1,15 @@
+<form>
+Email: <input type="text" [(ngModel)]="user.email" name="email"/><br />
+Name: <input type="text" [(ngModel)]="user.name" name="name"/><br />
+<input type="submit" (click)="addUser()" value="Add User"/>
+</form>
+
+<br />
+<table>
+<tr *ngFor="let user of res" >
+<td>{{user.email}}
+</td>
+<td>{{user.name}}</td>
+</tr>
+</table>
+

guest/webservices/rest-client/rest-client/src/app/users.component.ts

@@ -0,0 +1,39 @@
+import { Component } from '@angular/core';
+import {UserService, User} from './app.service';
+
+@Component({
+  selector: 'users-page',
+  providers: [UserService],
+  templateUrl: './users.component.html',
+  styleUrls: ['./app.component.css']
+})
+export class UsersComponent {
+  title = 'Users';
+  
+  constructor(
+        private _service:UserService){}
+     
+    public user = {email: "", name: ""}; 	
+	public res=[];
+ 
+    addUser() {
+      this._service.addUser(this.user)
+		.subscribe( () => this.getUsers());
+    }
+    
+    getUsers() {
+      this._service.getUsers()
+        .subscribe(
+          users => {
+	        this.res=[];
+            users.forEach(usr => {
+              this.res.push(
+                new User(
+                  usr.email,
+                  usr.name
+                )
+              )
+            });
+          });
+    }
+}