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

.gitignore

@@ -33,3 +33,11 @@ spring-openid/src/main/resources/application.properties
 spring-security-openid/src/main/resources/application.properties
 
 spring-all/*.log
+
+*.jar
+
+SpringDataInjectionDemo/.mvn/wrapper/maven-wrapper.properties
+
+spring-call-getters-using-reflection/.mvn/wrapper/maven-wrapper.properties
+
+spring-check-if-a-property-is-null/.mvn/wrapper/maven-wrapper.properties

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

@@ -186,4 +186,4 @@ public class HillClimbing {
         return stackHeuristics;
     }
 
-}
+}

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

@@ -40,4 +40,4 @@ public class State {
     public void setHeuristics(int heuristics) {
         this.heuristics = heuristics;
     }
-}
+}

algorithms/src/main/java/com/baeldung/algorithms/minimax/GameOfBones.java

@@ -0,0 +1,14 @@
+package com.baeldung.algorithms.minimax;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+class GameOfBones {
+    static List<Integer> getPossibleStates(int noOfBonesInHeap) {
+        return IntStream.rangeClosed(1, 3).boxed()
+          .map(i -> noOfBonesInHeap - i)
+          .filter(newHeapCount -> newHeapCount >= 0)
+          .collect(Collectors.toList());
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/minimax/MiniMax.java

@@ -0,0 +1,60 @@
+package com.baeldung.algorithms.minimax;
+
+import java.util.Comparator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+public class MiniMax {
+    private Tree tree;
+
+    public Tree getTree() {
+        return tree;
+    }
+
+    public void constructTree(int noOfBones) {
+        tree = new Tree();
+        Node root = new Node(noOfBones, true);
+        tree.setRoot(root);
+        constructTree(root);
+    }
+
+    private void constructTree(Node node) {
+        List<Integer> listofPossibleHeaps = GameOfBones.getPossibleStates(node.getNoOfBones());
+        boolean isMaxPlayer = !node.isMaxPlayer();
+        listofPossibleHeaps.forEach(n -> {
+            Node newNode = new Node(n, isMaxPlayer);
+            node.addChild(newNode);
+            if (newNode.getNoOfBones() > 0) {
+                constructTree(newNode);
+            }
+        });
+    }
+
+    public boolean checkWin() {
+        Node root = tree.getRoot();
+        checkWin(root);
+        return root.getScore() == 1;
+    }
+
+    private void checkWin(Node node) {
+        List<Node> children = node.getChildren();
+        boolean isMaxPlayer = node.isMaxPlayer();
+        children.forEach(child -> {
+            if (child.getNoOfBones() == 0) {
+                child.setScore(isMaxPlayer ? 1 : -1);
+            } else {
+                checkWin(child);
+            }
+        });
+        Node bestChild = findBestChild(isMaxPlayer, children);
+        node.setScore(bestChild.getScore());
+    }
+
+    private Node findBestChild(boolean isMaxPlayer, List<Node> children) {
+        Comparator<Node> byScoreComparator = Comparator.comparing(Node::getScore);
+
+        return children.stream()
+          .max(isMaxPlayer ? byScoreComparator : byScoreComparator.reversed())
+          .orElseThrow(NoSuchElementException::new);
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/minimax/Node.java

@@ -0,0 +1,42 @@
+package com.baeldung.algorithms.minimax;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Node {
+    private int noOfBones;
+    private boolean isMaxPlayer;
+    private int score;
+    private List<Node> children;
+
+    public Node(int noOfBones, boolean isMaxPlayer) {
+        this.noOfBones = noOfBones;
+        this.isMaxPlayer = isMaxPlayer;
+        children = new ArrayList<>();
+    }
+
+    int getNoOfBones() {
+        return noOfBones;
+    }
+
+    boolean isMaxPlayer() {
+        return isMaxPlayer;
+    }
+
+    int getScore() {
+        return score;
+    }
+
+    void setScore(int score) {
+        this.score = score;
+    }
+
+    List<Node> getChildren() {
+        return children;
+    }
+
+    void addChild(Node newNode) {
+        children.add(newNode);
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/minimax/Tree.java

@@ -0,0 +1,16 @@
+package com.baeldung.algorithms.minimax;
+
+public class Tree {
+    private Node root;
+
+    Tree() {
+    }
+
+    Node getRoot() {
+        return root;
+    }
+
+    void setRoot(Node root) {
+        this.root = root;
+    }
+}

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

@@ -55,4 +55,4 @@ public class HillClimbingAlgorithmTest {
         State nextState = hillClimbing.findNextState(currentState, goalStack);
         assertTrue(nextState.getHeuristics() > currentState.getHeuristics());
     }
-}
+}

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

@@ -0,0 +1,92 @@
+package algorithms;
+
+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 {
+    Tree gameTree;
+    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);
+    }
+
+}

algorithms/src/test/java/algorithms/minimax/MinimaxTest.java

@@ -0,0 +1,36 @@
+package algorithms.minimax;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+import com.baeldung.algorithms.minimax.MiniMax;
+import com.baeldung.algorithms.minimax.Tree;
+
+public class MinimaxTest {
+    private Tree gameTree;
+    private MiniMax miniMax;
+
+    @Before
+    public void initMiniMaxUtility() {
+        miniMax = new MiniMax();
+    }
+
+    @Test
+    public void givenMiniMax_whenConstructTree_thenNotNullTree() {
+        assertNull(gameTree);
+        miniMax.constructTree(6);
+        gameTree = miniMax.getTree();
+        assertNotNull(gameTree);
+    }
+
+    @Test
+    public void givenMiniMax_whenCheckWin_thenComputeOptimal() {
+        miniMax.constructTree(6);
+        boolean result = miniMax.checkWin();
+        assertTrue(result);
+        miniMax.constructTree(8);
+        result = miniMax.checkWin();
+        assertFalse(result);
+    }
+}

camel-api/README.md

@@ -0,0 +1,15 @@
+Example for the Article on Camel API with SpringBoot
+
+to start up, run:
+	mvn spring-boot:run
+	
+them, do a POST http request to:
+	http://localhost:8080/camel/api/bean 
+
+with the HEADER: Content-Type: application/json, 
+
+and a BODY Payload like {"id": 1,"name": "World"}
+
+and we will get a return code of 201 and the response: Hello, World - if the transform() method from Application class is uncommented and the process() method is commented
+
+or return code of 201 and the response: {"id": 10,"name": "Hello, World"} - if the transform() method from Application class is commented and the process() method is uncommented 

camel-api/pom.xml

@@ -0,0 +1,80 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+	<modelVersion>4.0.0</modelVersion>
+
+	<groupId>com.example</groupId>
+	<artifactId>spring-boot-camel</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+
+	<name>Spring-Boot - Camel API</name>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
+		<maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
+		<camel.version>2.19.1</camel.version>
+	    <spring-boot-starter.version>1.5.4.RELEASE</spring-boot-starter.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.apache.camel</groupId>
+			<artifactId>camel-servlet-starter</artifactId>
+			<version>${camel.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.camel</groupId>
+			<artifactId>camel-jackson-starter</artifactId>
+			<version>${camel.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.camel</groupId>
+			<artifactId>camel-swagger-java-starter</artifactId>
+			<version>${camel.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.camel</groupId>
+			<artifactId>camel-spring-boot-starter</artifactId>
+			<version>${camel.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+			<version>${spring-boot-starter.version}</version>
+		</dependency>
+	</dependencies>
+	
+	<build>
+		<defaultGoal>spring-boot:run</defaultGoal>
+
+		<plugins>
+			<plugin>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>${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>
+				<version>${maven-surefire-plugin.version}</version>
+			</plugin>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<version>${spring-boot-starter.version}</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>repackage</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+</project>

camel-api/src/main/java/com/baeldung/camel/Application.java

@@ -0,0 +1,104 @@
+package com.baeldung.camel;
+
+import javax.ws.rs.core.MediaType;
+
+import org.apache.camel.CamelContext;
+import org.apache.camel.Exchange;
+import org.apache.camel.Processor;
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.component.servlet.CamelHttpTransportServlet;
+import org.apache.camel.impl.DefaultCamelContext;
+import org.apache.camel.model.rest.RestBindingMode;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.web.servlet.ServletRegistrationBean;
+import org.springframework.boot.web.support.SpringBootServletInitializer;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.stereotype.Component;
+
+@SpringBootApplication
+@ComponentScan(basePackages="com.baeldung.camel")
+public class Application extends SpringBootServletInitializer {
+
+    @Value("${server.port}")
+    String serverPort;
+    
+    @Value("${baeldung.api.path}")
+    String contextPath;
+    
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+
+    @Bean
+    ServletRegistrationBean servletRegistrationBean() {
+        ServletRegistrationBean servlet = new ServletRegistrationBean(new CamelHttpTransportServlet(), contextPath+"/*");
+        servlet.setName("CamelServlet");
+        return servlet;
+    }
+
+
+    @Component
+    class RestApi extends RouteBuilder {
+
+        @Override
+        public void configure() {
+
+            CamelContext context = new DefaultCamelContext();
+
+            
+            // http://localhost:8080/camel/api-doc
+            restConfiguration().contextPath(contextPath) //
+                .port(serverPort)
+                .enableCORS(true)
+                .apiContextPath("/api-doc")
+                .apiProperty("api.title", "Test REST API")
+                .apiProperty("api.version", "v1")
+                .apiProperty("cors", "true") // cross-site
+                .apiContextRouteId("doc-api")
+                .component("servlet")
+                .bindingMode(RestBindingMode.json)
+                .dataFormatProperty("prettyPrint", "true");
+/** 
+The Rest DSL supports automatic binding json/xml contents to/from POJOs using Camels Data Format.
+By default the binding mode is off, meaning there is no automatic binding happening for incoming and outgoing messages.
+You may want to use binding if you develop POJOs that maps to your REST services request and response types. 
+This allows you, as a developer, to work with the POJOs in Java code.
+*/         
+            
+            rest("/api/").description("Teste REST Service")
+                .id("api-route")
+                .post("/bean")
+                .produces(MediaType.APPLICATION_JSON)
+                .consumes(MediaType.APPLICATION_JSON)
+//                .get("/hello/{place}")
+                .bindingMode(RestBindingMode.auto)
+                .type(MyBean.class)
+                .enableCORS(true)
+//                .outType(OutBean.class)
+
+                .to("direct:remoteService");
+            
+       
+            from("direct:remoteService")
+                .routeId("direct-route")
+                .tracing()
+                .log(">>> ${body.id}")
+                .log(">>> ${body.name}")
+//                .transform().simple("blue ${in.body.name}")                
+                .process(new Processor() {
+                    @Override
+                    public void process(Exchange exchange) throws Exception {
+                        MyBean bodyIn = (MyBean) exchange.getIn().getBody();
+                        
+                        ExampleServices.example(bodyIn);
+
+                        exchange.getIn().setBody(bodyIn);
+                    }
+                })
+                .setHeader(Exchange.HTTP_RESPONSE_CODE, constant(201));
+        }
+    }
+}

camel-api/src/main/java/com/baeldung/camel/ExampleServices.java

@@ -0,0 +1,15 @@
+package com.baeldung.camel;
+
+/**
+ * a Mock class to show how some other layer
+ * (a persistence layer, for instance)
+ * could be used insida a Camel
+ * 
+ */
+public class ExampleServices {
+
+    public static void example(MyBean bodyIn) {
+        bodyIn.setName( "Hello, " + bodyIn.getName() );
+        bodyIn.setId(bodyIn.getId()*10);
+    }
+}

camel-api/src/main/java/com/baeldung/camel/MyBean.java

@@ -0,0 +1,18 @@
+package com.baeldung.camel;
+
+public class MyBean {
+    private Integer id;
+    private String name;
+    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;
+    }
+}

camel-api/src/main/resources/application.properties

@@ -0,0 +1,15 @@
+logging.config=classpath:logback.xml
+
+# the options from org.apache.camel.spring.boot.CamelConfigurationProperties can be configured here
+camel.springboot.name=MyCamel
+
+# lets listen on all ports to ensure we can be invoked from the pod IP
+server.address=0.0.0.0
+management.address=0.0.0.0
+
+# lets use a different management port in case you need to listen to HTTP requests on 8080
+management.port=8081
+
+# disable all management enpoints except health
+endpoints.enabled = true
+endpoints.health.enabled = true

camel-api/src/main/resources/application.yml

@@ -0,0 +1,27 @@
+server:
+  port: 8080
+
+# for example purposes of Camel version 2.18 and below
+baeldung:
+  api:
+    path: '/camel' 
+
+camel:
+  springboot:
+    # The Camel context name
+    name: ServicesRest
+
+# Binding health checks to a different port
+management:
+  port: 8081
+
+# disable all management enpoints except health
+endpoints:
+  enabled: false
+  health:
+    enabled: true
+
+# The application configuration properties
+quickstart:
+  generateOrderPeriod: 10s
+  processOrderPeriod: 30s

camel-api/src/main/resources/logback.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE xml>
+<configuration>
+
+  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+    <!-- encoders are assigned the type
+         ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
+    <encoder>
+      <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+    </encoder>
+  </appender>
+
+  <root level="info">
+    <appender-ref ref="STDOUT" />
+  </root>
+
+</configuration>

core-java/pom.xml

@@ -327,6 +327,22 @@
                 </executions>
             </plugin>
 
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>1.6.0</version>
+                <configuration>
+                    <executable>java</executable>
+                    <mainClass>com.baeldung.outofmemoryerror.OutOfMemoryGCLimitExceed</mainClass>
+                    <arguments>
+                        <argument>-Xmx300m</argument>
+                        <argument>-XX:+UseParallelGC</argument>
+                        <argument>-classpath</argument>
+                        <classpath/>
+                        <argument>com.baeldung.outofmemoryerror.OutOfMemoryGCLimitExceed</argument>
+                    </arguments>
+                </configuration>
+            </plugin>
         </plugins>
 
     </build>

core-java/src/main/java/com/baeldung/concurrent/blockingqueue/NumbersConsumer.java

@@ -6,7 +6,7 @@ public class NumbersConsumer implements Runnable {
     private final BlockingQueue<Integer> queue;
     private final int poisonPill;
 
-    public NumbersConsumer(BlockingQueue<Integer> queue, int poisonPill) {
+    NumbersConsumer(BlockingQueue<Integer> queue, int poisonPill) {
         this.queue = queue;
         this.poisonPill = poisonPill;
     }

core-java/src/main/java/com/baeldung/concurrent/blockingqueue/NumbersProducer.java

@@ -9,7 +9,7 @@ public class NumbersProducer implements Runnable {
     private final int poisonPill;
     private final int poisonPillPerProducer;
 
-    public NumbersProducer(BlockingQueue<Integer> numbersQueue, int poisonPill, int poisonPillPerProducer) {
+    NumbersProducer(BlockingQueue<Integer> numbersQueue, int poisonPill, int poisonPillPerProducer) {
         this.numbersQueue = numbersQueue;
         this.poisonPill = poisonPill;
         this.poisonPillPerProducer = poisonPillPerProducer;

core-java/src/main/java/com/baeldung/concurrent/countdownlatch/BrokenWorker.java

@@ -7,7 +7,7 @@ public class BrokenWorker implements Runnable {
     private final List<String> outputScraper;
     private final CountDownLatch countDownLatch;
 
-    public BrokenWorker(final List<String> outputScraper, final CountDownLatch countDownLatch) {
+    BrokenWorker(final List<String> outputScraper, final CountDownLatch countDownLatch) {
         this.outputScraper = outputScraper;
         this.countDownLatch = countDownLatch;
     }

core-java/src/main/java/com/baeldung/concurrent/countdownlatch/WaitingWorker.java

@@ -10,7 +10,7 @@ public class WaitingWorker implements Runnable {
     private final CountDownLatch callingThreadBlocker;
     private final CountDownLatch completedThreadCounter;
 
-    public WaitingWorker(final List<String> outputScraper, final CountDownLatch readyThreadCounter, final CountDownLatch callingThreadBlocker, CountDownLatch completedThreadCounter) {
+    WaitingWorker(final List<String> outputScraper, final CountDownLatch readyThreadCounter, final CountDownLatch callingThreadBlocker, CountDownLatch completedThreadCounter) {
 
         this.outputScraper = outputScraper;
         this.readyThreadCounter = readyThreadCounter;

core-java/src/main/java/com/baeldung/concurrent/countdownlatch/Worker.java

@@ -7,7 +7,7 @@ public class Worker implements Runnable {
     private final List<String> outputScraper;
     private final CountDownLatch countDownLatch;
 
-    public Worker(final List<String> outputScraper, final CountDownLatch countDownLatch) {
+    Worker(final List<String> outputScraper, final CountDownLatch countDownLatch) {
         this.outputScraper = outputScraper;
         this.countDownLatch = countDownLatch;
     }

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

@@ -7,9 +7,6 @@ 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;
@@ -19,7 +16,7 @@ public class CyclicBarrierDemo {
     private int NUM_WORKERS;
 
 
-    public void runSimulation(int numWorkers, int numberOfPartialResults) {
+    private void runSimulation(int numWorkers, int numberOfPartialResults) {
         NUM_PARTIAL_RESULTS = numberOfPartialResults;
         NUM_WORKERS = numWorkers;
 
@@ -49,9 +46,7 @@ public class CyclicBarrierDemo {
             try {
                 System.out.println(thisThreadName + " waiting for others to reach barrier.");
                 cyclicBarrier.await();
-            } catch (InterruptedException e) {
-                e.printStackTrace();
-            } catch (BrokenBarrierException e) {
+            } catch (InterruptedException | BrokenBarrierException e) {
                 e.printStackTrace();
             }
         }

core-java/src/main/java/com/baeldung/concurrent/delayqueue/DelayObject.java

@@ -9,7 +9,7 @@ public class DelayObject implements Delayed {
     private String data;
     private long startTime;
 
-    public DelayObject(String data, long delayInMilliseconds) {
+    DelayObject(String data, long delayInMilliseconds) {
         this.data = data;
         this.startTime = System.currentTimeMillis() + delayInMilliseconds;
     }

core-java/src/main/java/com/baeldung/concurrent/delayqueue/DelayQueueConsumer.java

@@ -7,9 +7,9 @@ import java.util.concurrent.atomic.AtomicInteger;
 public class DelayQueueConsumer implements Runnable {
     private BlockingQueue<DelayObject> queue;
     private final Integer numberOfElementsToTake;
-    public final AtomicInteger numberOfConsumedElements = new AtomicInteger();
+    final AtomicInteger numberOfConsumedElements = new AtomicInteger();
 
-    public DelayQueueConsumer(BlockingQueue<DelayObject> queue, Integer numberOfElementsToTake) {
+    DelayQueueConsumer(BlockingQueue<DelayObject> queue, Integer numberOfElementsToTake) {
         this.queue = queue;
         this.numberOfElementsToTake = numberOfElementsToTake;
     }

core-java/src/main/java/com/baeldung/concurrent/delayqueue/DelayQueueProducer.java

@@ -9,9 +9,9 @@ public class DelayQueueProducer implements Runnable {
     private final Integer numberOfElementsToProduce;
     private final Integer delayOfEachProducedMessageMilliseconds;
 
-    public DelayQueueProducer(BlockingQueue<DelayObject> queue,
-                              Integer numberOfElementsToProduce,
-                              Integer delayOfEachProducedMessageMilliseconds) {
+    DelayQueueProducer(BlockingQueue<DelayObject> queue,
+                       Integer numberOfElementsToProduce,
+                       Integer delayOfEachProducedMessageMilliseconds) {
         this.queue = queue;
         this.numberOfElementsToProduce = numberOfElementsToProduce;
         this.delayOfEachProducedMessageMilliseconds = delayOfEachProducedMessageMilliseconds;

core-java/src/main/java/com/baeldung/concurrent/diningphilosophers/Philosopher.java

@@ -5,7 +5,7 @@ public class Philosopher implements Runnable {
     private final Object leftFork;
     private final Object rightFork;
 
-    public Philosopher(Object left, Object right) {
+    Philosopher(Object left, Object right) {
         this.leftFork = left;
         this.rightFork = right;
     }
@@ -30,7 +30,6 @@ public class Philosopher implements Runnable {
             }
         } catch (InterruptedException e) {
             Thread.currentThread().interrupt();
-            return;
         }
     }
 }

core-java/src/main/java/com/baeldung/concurrent/future/FactorialSquareCalculator.java

@@ -7,7 +7,7 @@ public class FactorialSquareCalculator extends RecursiveTask<Integer> {
 
     final private Integer n;
 
-    public FactorialSquareCalculator(Integer n) {
+    FactorialSquareCalculator(Integer n) {
         this.n = n;
     }