Merge pull request #1 from eugenp/master

Merge remote changes

algorithms/src/main/java/com/baeldung/algorithms/BinarySearch.java

@@ -0,0 +1,26 @@
+public class BinarySearch {
+
+    public int runBinarySearch() {
+        int[] sortedArray = { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
+        int key = 6;
+
+        int low = 0;
+        int high = sortedArray.length - 1;
+        int index = Integer.MAX_VALUE;
+
+        while (low <= high) {
+
+            int mid = (low + high) / 2;
+
+            if (sortedArray[mid] < key) {
+                low = mid + 1;
+            } else if (sortedArray[mid] > key) {
+                high = mid - 1;
+            } else if (sortedArray[mid] == key) {
+                index = mid;
+                break;
+            }
+        }
+        return index;
+    }
+}

algorithms/src/test/java/algorithms/BinarySearchTest.java

@@ -0,0 +1,14 @@
+import org.junit.Assert;
+import org.junit.Test;
+
+
+public class BinarySearchTest {
+
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        int expectedIndexForSearchKey = 7;
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearch());
+    }
+
+}

apache-shiro/.gitignore

@@ -0,0 +1,4 @@
+
+/.idea/
+/target/
+/apache-shiro.iml

apache-shiro/pom.xml

@@ -0,0 +1,65 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>apache-shiro</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <properties>
+        <apache-shiro-core-version>1.4.0</apache-shiro-core-version>
+        <log4j-version>1.2.17</log4j-version>
+        <slf4j-version>1.7.25</slf4j-version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.shiro</groupId>
+            <artifactId>shiro-core</artifactId>
+            <version>${apache-shiro-core-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>jcl-over-slf4j</artifactId>
+            <version>${slf4j-version}</version>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-log4j12</artifactId>
+            <version>${slf4j-version}</version>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>log4j</groupId>
+            <artifactId>log4j</artifactId>
+            <version>${log4j-version}</version>
+            <scope>runtime</scope>
+        </dependency>
+
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.6.2</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    
+</project>

apache-shiro/src/main/java/com/baeldung/Main.java

@@ -0,0 +1,85 @@
+package com.baeldung;
+
+import org.apache.shiro.SecurityUtils;
+import org.apache.shiro.authc.*;
+import org.apache.shiro.mgt.DefaultSecurityManager;
+import org.apache.shiro.mgt.SecurityManager;
+import org.apache.shiro.realm.Realm;
+import org.apache.shiro.realm.text.IniRealm;
+import org.apache.shiro.session.Session;
+import org.apache.shiro.subject.Subject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class Main {
+
+    private static final transient Logger log = LoggerFactory.getLogger(Main.class);
+
+    public static void main(String[] args) {
+
+        Realm realm = new MyCustomRealm();
+        SecurityManager securityManager = new DefaultSecurityManager(realm);
+
+        SecurityUtils.setSecurityManager(securityManager);
+        Subject currentUser = SecurityUtils.getSubject();
+
+        if (!currentUser.isAuthenticated()) {
+          UsernamePasswordToken token 
+            = new UsernamePasswordToken("user", "password");
+          token.setRememberMe(true);
+          try {
+              currentUser.login(token);
+          } catch (UnknownAccountException uae) {
+              log.error("Username Not Found!", uae);
+          } catch (IncorrectCredentialsException ice) {
+              log.error("Invalid Credentials!", ice);
+          } catch (LockedAccountException lae) {
+              log.error("Your Account is Locked!", lae);
+          } catch (AuthenticationException ae) {
+              log.error("Unexpected Error!", ae);
+          }
+        }
+
+        log.info("User [" + currentUser.getPrincipal() + "] logged in successfully.");
+
+        if (currentUser.hasRole("admin")) {
+            log.info("Welcome Admin");
+        } else if(currentUser.hasRole("editor")) {
+            log.info("Welcome, Editor!");
+        } else if(currentUser.hasRole("author")) {
+            log.info("Welcome, Author");
+        } else {
+            log.info("Welcome, Guest");
+        }
+
+        if(currentUser.isPermitted("articles:compose")) {
+            log.info("You can compose an article");
+        } else {
+            log.info("You are not permitted to compose an article!");
+        }
+
+        if(currentUser.isPermitted("articles:save")) {
+            log.info("You can save articles");
+        } else {
+            log.info("You can not save articles");
+        }
+
+        if(currentUser.isPermitted("articles:publish")) {
+            log.info("You can publish articles");
+        } else {
+            log.info("You can not publish articles");
+        }
+
+        Session session = currentUser.getSession();
+        session.setAttribute("key", "value");
+        String value = (String) session.getAttribute("key");
+        if (value.equals("value")) {
+            log.info("Retrieved the correct value! [" + value + "]");
+        }
+
+        currentUser.logout();
+
+        System.exit(0);
+    }
+
+}

apache-shiro/src/main/java/com/baeldung/MyCustomRealm.java

@@ -0,0 +1,102 @@
+package com.baeldung;
+
+import org.apache.shiro.authc.*;
+import org.apache.shiro.authz.AuthorizationInfo;
+import org.apache.shiro.authz.SimpleAuthorizationInfo;
+import org.apache.shiro.realm.jdbc.JdbcRealm;
+import org.apache.shiro.subject.PrincipalCollection;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.util.*;
+
+public class MyCustomRealm extends JdbcRealm {
+
+    private Map<String, String> credentials = new HashMap<>();
+    private Map<String, Set<String>> roles = new HashMap<>();
+    private Map<String, Set<String>> perm = new HashMap<>();
+
+    {
+      credentials.put("user", "password");
+      credentials.put("user2", "password2");
+      credentials.put("user3", "password3");
+
+      roles.put("user", new HashSet<>(Arrays.asList("admin")));
+      roles.put("user2", new HashSet<>(Arrays.asList("editor")));
+      roles.put("user3", new HashSet<>(Arrays.asList("author")));
+
+      perm.put("admin", new HashSet<>(Arrays.asList("*")));
+      perm.put("editor", new HashSet<>(Arrays.asList("articles:*")));
+      perm.put("author",
+        new HashSet<>(Arrays.asList("articles:compose",
+          "articles:save")));
+
+    }
+
+    @Override
+    protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token)
+      throws AuthenticationException {
+
+        UsernamePasswordToken uToken = (UsernamePasswordToken) token;
+
+        if(uToken.getUsername() == null
+          || uToken.getUsername().isEmpty()
+          || !credentials.containsKey(uToken.getUsername())
+          ) {
+            throw new UnknownAccountException("username not found!");
+        }
+
+
+        return new SimpleAuthenticationInfo(
+          uToken.getUsername(), credentials.get(uToken.getUsername()),
+          getName());
+    }
+
+    @Override
+    protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {
+        Set<String> roleNames = new HashSet<>();
+        Set<String> permissions = new HashSet<>();
+
+        principals.forEach(p -> {
+            try {
+                Set<String> roles = getRoleNamesForUser(null, (String) p);
+                roleNames.addAll(roles);
+                permissions.addAll(getPermissions(null, null,roles));
+            } catch (SQLException e) {
+                e.printStackTrace();
+            }
+        });
+
+        SimpleAuthorizationInfo info = new SimpleAuthorizationInfo(roleNames);
+        info.setStringPermissions(permissions);
+        return info;
+    }
+
+    @Override
+    protected Set<String> getRoleNamesForUser(Connection conn, String username) throws SQLException {
+        if(!roles.containsKey(username)) {
+            throw new SQLException("username not found!");
+        }
+
+       return roles.get(username);
+    }
+
+    @Override
+    protected Set<String> getPermissions(Connection conn, String username, Collection<String> roleNames) throws SQLException {
+        for (String role : roleNames) {
+            if (!perm.containsKey(role)) {
+                throw new SQLException("role not found!");
+            }
+        }
+
+        Set<String> finalSet = new HashSet<>();
+        for (String role : roleNames) {
+            finalSet.addAll(perm.get(role));
+        }
+
+        return finalSet;
+    }
+
+}

apache-shiro/src/main/resources/log4j.properties

@@ -0,0 +1,12 @@
+log4j.rootLogger=INFO, stdout
+
+log4j.appender.stdout=org.apache.log4j.ConsoleAppender
+log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
+log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m %n
+
+log4j.logger.org.apache=WARN
+
+log4j.logger.org.apache.shiro=INFO
+
+log4j.logger.org.apache.shiro.util.ThreadContext=WARN
+log4j.logger.org.apache.shiro.cache.ehcache.EhCache=WARN

apache-shiro/src/main/resources/shiro.ini

@@ -0,0 +1,9 @@
+[users]
+user = password,admin
+user2 = password2,editor
+user3 = password3,author
+
+[roles]
+admin = *
+editor = articles:*
+author = articles:compose,articles:save

apache-velocity/src/main/webapp/WEB-INF/velocity.properties

@@ -1,4 +1,4 @@
 resource.loader=webapp
 webapp.resource.loader.class=org.apache.velocity.tools.view.WebappResourceLoader
-webapp.resource.loader.path = .
+webapp.resource.loader.path = 
 webapp.resource.loader.cache = true

asciidoctor/README.md

@@ -1,3 +1,4 @@
 ### Relevant articles
 
-- [Introduction to Asciidoctor](http://www.baeldung.com/introduction-to-asciidoctor)
+- [Introduction to Asciidoctor](http://www.baeldung.com/introduction-to-asciidoctor)
+- [Generating a Book with Asciidoctor](http://www.baeldung.com/asciidoctor-book)

bootique/config.yml

@@ -0,0 +1,11 @@
+log:
+  level: warn
+  appenders:
+    - type: file
+      logFormat: '%c{20}: %m%n'
+      file: /home/logger.log
+
+jetty:
+  context: /hello
+  connector:
+    port: 10001

bootique/dependency-reduced-pom.xml

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <parent>
+    <artifactId>bootique-parent</artifactId>
+    <groupId>io.bootique.parent</groupId>
+    <version>0.12</version>
+  </parent>
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.baeldung.bootique</groupId>
+  <artifactId>bootique</artifactId>
+  <name>bootique</name>
+  <version>1.0-SNAPSHOT</version>
+  <url>http://maven.apache.org</url>
+  <build>
+    <plugins>
+      <plugin>
+        <artifactId>maven-shade-plugin</artifactId>
+      </plugin>
+    </plugins>
+  </build>
+  <dependencies>
+    <dependency>
+      <groupId>io.bootique</groupId>
+      <artifactId>bootique-test</artifactId>
+      <version>0.23</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>3.8.1</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+  <dependencyManagement>
+    <dependencies>
+      <dependency>
+        <groupId>io.bootique.bom</groupId>
+        <artifactId>bootique-bom</artifactId>
+        <version>0.23</version>
+        <type>pom</type>
+        <scope>import</scope>
+      </dependency>
+    </dependencies>
+  </dependencyManagement>
+  <properties>
+    <main.class>com.baeldung.bootique.App</main.class>
+  </properties>
+</project>
+

bootique/pom.xml

@@ -0,0 +1,66 @@
+<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/maven-v4_0_0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.baeldung.bootique</groupId>
+	<artifactId>bootique</artifactId>
+	<packaging>jar</packaging>
+	<version>1.0-SNAPSHOT</version>
+	<name>bootique</name>
+	<url>http://maven.apache.org</url>
+
+	<properties>
+		<main.class>com.baeldung.bootique.App</main.class>
+	</properties>
+
+	<parent>
+		<groupId>io.bootique.parent</groupId>
+		<artifactId>bootique-parent</artifactId>
+		<version>0.12</version>
+	</parent>
+
+	<dependencyManagement>
+		<dependencies>
+			<dependency>
+				<groupId>io.bootique.bom</groupId>
+				<artifactId>bootique-bom</artifactId>
+				<version>0.23</version>
+				<type>pom</type>
+				<scope>import</scope>
+			</dependency>
+		</dependencies>
+	</dependencyManagement>
+
+	<dependencies>
+		<dependency>
+			<groupId>io.bootique.jersey</groupId>
+			<artifactId>bootique-jersey</artifactId>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>io.bootique.logback</groupId>
+			<artifactId>bootique-logback</artifactId>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>io.bootique</groupId>
+			<artifactId>bootique-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>4.12</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-shade-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

bootique/src/main/java/com/baeldung/bootique/App.java

@@ -0,0 +1,41 @@
+package com.baeldung.bootique;
+
+import com.baeldung.bootique.module.ModuleBinder;
+import com.baeldung.bootique.router.IndexController;
+import com.baeldung.bootique.router.SaveController;
+import com.google.inject.Module;
+import io.bootique.Bootique;
+import io.bootique.jersey.JerseyModule;
+import io.bootique.log.BootLogger;
+
+import java.util.function.Supplier;
+
+public class App {
+
+    public static void main(String[] args) {
+        Module module = binder -> JerseyModule.extend(binder).addResource(IndexController.class)
+          .addResource(SaveController.class);
+        Bootique.app(args).module(module).module(ModuleBinder.class).bootLogger(new BootLogger() {
+            @Override
+            public void trace(Supplier<String> arg0) {
+                // ...
+            }
+
+            @Override
+            public void stdout(String arg0) {
+                // ...
+            }
+
+            @Override
+            public void stderr(String arg0, Throwable arg1) {
+                // ...
+            }
+
+            @Override
+            public void stderr(String arg0) {
+                // ...
+            }
+        }).autoLoadModules().exec();
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/module/ModuleBinder.java

@@ -0,0 +1,15 @@
+package com.baeldung.bootique.module;
+
+import com.baeldung.bootique.service.HelloService;
+import com.baeldung.bootique.service.impl.HelloServiceImpl;
+import com.google.inject.Binder;
+import com.google.inject.Module;
+
+public class ModuleBinder implements Module {
+
+    @Override
+    public void configure(Binder binder) {
+        binder.bind(HelloService.class).to(HelloServiceImpl.class);
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/module/ModuleProvider.java

@@ -0,0 +1,13 @@
+package com.baeldung.bootique.module;
+
+import com.google.inject.Module;
+import io.bootique.BQModuleProvider;
+
+public class ModuleProvider implements BQModuleProvider {
+
+    @Override
+    public Module module() {
+        return new ModuleBinder();
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/router/IndexController.java

@@ -0,0 +1,14 @@
+package com.baeldung.bootique.router;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+
+@Path("/")
+public class IndexController {
+
+    @GET
+    public String index() {
+        return "Hello, baeldung!";
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/router/SaveController.java

@@ -0,0 +1,20 @@
+package com.baeldung.bootique.router;
+
+import com.baeldung.bootique.service.HelloService;
+import com.google.inject.Inject;
+
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+
+@Path("/save")
+public class SaveController {
+
+    @Inject
+    HelloService helloService;
+
+    @POST
+    public String save() {
+        return "Data Saved!";
+    }
+
+}

bootique/src/main/java/com/baeldung/bootique/service/HelloService.java

@@ -0,0 +1,7 @@
+package com.baeldung.bootique.service;
+
+public interface HelloService {
+
+	boolean save();
+
+}

bootique/src/main/java/com/baeldung/bootique/service/impl/HelloServiceImpl.java

@@ -0,0 +1,12 @@
+package com.baeldung.bootique.service.impl;
+
+import com.baeldung.bootique.service.HelloService;
+
+public class HelloServiceImpl implements HelloService {
+
+	@Override
+	public boolean save() {
+		return true;
+	}
+
+}

bootique/src/main/resources/META-INF/services/io.bootique.BQModuleProvider

@@ -0,0 +1 @@
+com.baeldung.bootique.module.ModuleProvider

bootique/src/test/java/com/baeldung/bootique/AppTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.bootique;
+
+import com.baeldung.bootique.service.HelloService;
+import io.bootique.BQRuntime;
+import io.bootique.test.junit.BQDaemonTestFactory;
+import io.bootique.test.junit.BQTestFactory;
+import org.junit.Rule;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class AppTest {
+
+    @Rule
+    public BQTestFactory bqTestFactory = new BQTestFactory();
+
+    @Rule
+    public BQDaemonTestFactory bqDaemonTestFactory = new BQDaemonTestFactory();
+
+    @Test
+    public void givenService_expectBoolen() {
+        BQRuntime runtime = bqTestFactory.app("--server").autoLoadModules().createRuntime();
+        HelloService service = runtime.getInstance(HelloService.class);
+        assertEquals(true, service.save());
+    }
+
+}

core-java-9/src/main/java/com/baeldung/java9/process/ServiceMain.java

@@ -6,7 +6,7 @@ public class ServiceMain {
 
     public static void main(String[] args) throws InterruptedException {
         ProcessHandle thisProcess = ProcessHandle.current();
-        long pid = thisProcess.getPid();
+        long pid = thisProcess.pid();
 
         Optional<String[]> opArgs = Optional.ofNullable(args);
         String procName = opArgs.map(str -> str.length > 0 ? str[0] : null).orElse(System.getProperty("sun.java.command"));

core-java-9/src/test/java/com/baeldung/java9/language/Java9ObjectsAPIUnitTest.java

@@ -0,0 +1,86 @@
+package com.baeldung.java9.language;
+
+import org.junit.Test;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+
+import static org.hamcrest.Matchers.*;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+public class Java9ObjectsAPIUnitTest {
+
+    private List<String> aMethodReturningNullList(){
+        return null;
+    }
+
+    @Test
+    public void givenNullObject_whenRequireNonNullElse_thenElse(){
+        List<String> aList = Objects.<List>requireNonNullElse(
+                aMethodReturningNullList(), Collections.EMPTY_LIST);
+        assertThat(aList, is(Collections.EMPTY_LIST));
+    }
+
+    private List<String> aMethodReturningNonNullList(){
+        return List.of("item1", "item2");
+    }
+
+    @Test
+    public void givenObject_whenRequireNonNullElse_thenObject(){
+        List<String> aList = Objects.<List>requireNonNullElse(
+                aMethodReturningNonNullList(), Collections.EMPTY_LIST);
+        assertThat(aList, is(List.of("item1", "item2")));
+    }
+
+    @Test(expected = NullPointerException.class)
+    public void givenNull_whenRequireNonNullElse_thenException(){
+        Objects.<List>requireNonNullElse(null, null);
+    }
+
+    @Test
+    public void givenObject_whenRequireNonNullElseGet_thenObject(){
+        List<String> aList = Objects.<List>requireNonNullElseGet(null, List::of);
+        assertThat(aList, is(List.of()));
+    }
+
+    @Test
+    public void givenNumber_whenInvokeCheckIndex_thenNumber(){
+        int length = 5;
+        assertThat(Objects.checkIndex(4, length), is(4));
+    }
+
+    @Test(expected = IndexOutOfBoundsException.class)
+    public void givenOutOfRangeNumber_whenInvokeCheckIndex_thenException(){
+        int length = 5;
+        Objects.checkIndex(5, length);
+    }
+
+
+    @Test
+    public void givenSubRange_whenCheckFromToIndex_thenNumber(){
+        int length = 6;
+        assertThat(Objects.checkFromToIndex(2,length,length), is(2));
+    }
+
+    @Test(expected = IndexOutOfBoundsException.class)
+    public void givenInvalidSubRange_whenCheckFromToIndex_thenException(){
+        int length = 6;
+        Objects.checkFromToIndex(2,7,length);
+    }
+
+
+    @Test
+    public void givenSubRange_whenCheckFromIndexSize_thenNumber(){
+        int length = 6;
+        assertThat(Objects.checkFromIndexSize(2,3,length), is(2));
+    }
+
+    @Test(expected = IndexOutOfBoundsException.class)
+    public void givenInvalidSubRange_whenCheckFromIndexSize_thenException(){
+        int length = 6;
+        Objects.checkFromIndexSize(2, 6, length);
+    }
+
+
+}

core-java/hashcode/pom.xml

@@ -1,39 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0"
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <groupId>com.baeldung.hashcode</groupId>
-    <artifactId>hashcode</artifactId>
-    <version>1.0</version>
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <configuration>
-                    <source>1.8</source>
-                    <target>1.8</target>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
-    <dependencies>
-        <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <version>4.12</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-api</artifactId>
-            <version>1.7.25</version>
-        </dependency>
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-simple</artifactId>
-            <version>1.7.25</version>
-        </dependency>
-    </dependencies>
-</project>

core-java/hashcode/src/main/java/com/baeldung/application/Application.java

@@ -1,23 +0,0 @@
-package com.baeldung.application;
-
-import com.baeldung.entities.User;
-import java.util.HashMap;
-import java.util.Map;
-
-public class Application {
-
-    public static void main(String[] args) {
-        Map<User, User> users = new HashMap<>();
-        User user1 = new User(1L, "John", "john@domain.com");
-        User user2 = new User(2L, "Jennifer", "jennifer@domain.com");
-        User user3 = new User(3L, "Mary", "mary@domain.com");
-
-        users.put(user1, user1);
-        users.put(user2, user2);
-        users.put(user3, user3);
-
-        if (users.containsKey(user1)) {
-            System.out.print("User found in the collection");
-        }
-    }
-}

core-java/hashcode/src/main/java/com/baeldung/entities/User.java

@@ -1,38 +0,0 @@
-package com.baeldung.entities;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-public class User {
-
-    private final Logger logger = LoggerFactory.getLogger(User.class);
-    private long id;
-    private String name;
-    private String email;
-
-    public User(long id, String name, String email) {
-        this.id = id;
-        this.name = name;
-        this.email = email;
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null) return false;
-        if (this.getClass() != o.getClass()) return false;
-        User user = (User) o;
-        return id != user.id && (!name.equals(user.name) && !email.equals(user.email));
-    }
-    	
-    @Override
-    public int hashCode() {
-        int hash = 7;
-        hash = 31 * hash + (int) id;
-        hash = 31 * hash + (name == null ? 0 : name.hashCode());
-        hash = 31 * hash + (email == null ? 0 : email.hashCode());
-        logger.info("hashCode() method called - Computed hash: " + hash);
-        return hash;
-    }
-    // getters and setters here
-}

core-java/hashcode/src/test/java/com/baeldung/application/ApplicationTest.java

@@ -1,30 +0,0 @@
-package com.baeldung.application;
-
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-import java.io.ByteArrayOutputStream;
-import java.io.PrintStream;
-import static org.junit.Assert.assertEquals;
-
-public class ApplicationTest {
-
-    private ByteArrayOutputStream outContent;
-
-    @Before
-    public void setUpPrintStreamInstance() throws Exception {
-        this.outContent = new ByteArrayOutputStream();
-        System.setOut(new PrintStream(outContent));
-    }
-
-    @After
-    public void tearDownByteArrayOutputStream() throws Exception {
-        outContent = null;
-    }
-
-    @Test
-    public void main_NoInputState_TextPrintedToConsole() throws Exception {
-        Application.main(new String[]{});
-        assertEquals("User found in the collection", outContent.toString());
-    }
-}

core-java/hashcode/src/test/java/com/baeldung/entities/UserTest.java

@@ -1,34 +0,0 @@
-package com.baeldung.entities;
-
-import org.junit.After;
-import org.junit.Assert;
-import org.junit.Before;
-import org.junit.Test;
-
-public class UserTest {
-
-    private User user;
-    private User comparisonUser;
-
-    @Before
-    public void setUpUserInstances() {
-        this.user = new User(1L, "test", "test@domain.com");
-        this.comparisonUser = this.user;
-    }
-
-    @After
-    public void tearDownUserInstances() {
-        user = null;
-        comparisonUser = null;
-    }
-
-    @Test
-    public void equals_EqualUserInstance_TrueAssertion(){
-        Assert.assertTrue(user.equals(comparisonUser));
-    }
-
-    @Test
-    public void hashCode_UserHash_TrueAssertion() {
-        Assert.assertEquals(1792276941, user.hashCode());
-    }
-}

core-java/pom.xml

@@ -80,7 +80,11 @@
         </dependency>
 
         <!-- logging -->
-
+       <dependency>
+            <groupId>log4j</groupId>
+            <artifactId>log4j</artifactId>
+            <version>1.2.17</version>
+        </dependency>
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-api</artifactId>

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

@@ -15,14 +15,12 @@ public class CyclicBarrierDemo {
     private int NUM_PARTIAL_RESULTS;
     private int NUM_WORKERS;
 
-
     private 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 "
+        System.out.println("Spawning " + NUM_WORKERS + " worker threads to compute " + NUM_PARTIAL_RESULTS + " partial results each");
-                + NUM_PARTIAL_RESULTS + " partial results each");
         for (int i = 0; i < NUM_WORKERS; i++) {
             Thread worker = new Thread(new NumberCruncherThread());
             worker.setName("Thread " + i);
@@ -38,8 +36,7 @@ public class CyclicBarrierDemo {
             List<Integer> partialResult = new ArrayList<>();
             for (int i = 0; i < NUM_PARTIAL_RESULTS; i++) {
                 Integer num = random.nextInt(10);
-                System.out.println(thisThreadName
+                System.out.println(thisThreadName + ": Crunching some numbers! Final result - " + num);
-                        + ": Crunching some numbers! Final result - " + num);
                 partialResult.add(num);
             }
             partialResults.add(partialResult);
@@ -57,13 +54,12 @@ public class CyclicBarrierDemo {
         @Override
         public void run() {
             String thisThreadName = Thread.currentThread().getName();
-            System.out.println(thisThreadName + ": Computing final sum of " + NUM_WORKERS
+            System.out.println(thisThreadName + ": Computing final sum of " + NUM_WORKERS + " workers, having " + NUM_PARTIAL_RESULTS + " results each.");
-                    + " 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+" ");
+                    System.out.print(partialResult + " ");
                     sum += partialResult;
                 }
                 System.out.println();

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

@@ -15,7 +15,8 @@ public class Philosopher implements Runnable {
         Thread.sleep(((int) (Math.random() * 100)));
     }
 
-    @Override public void run() {
+    @Override
+    public void run() {
         try {
             while (true) {
                 doAction(System.nanoTime() + ": Thinking"); // thinking

core-java/src/main/java/com/baeldung/concurrent/executorservice/ExecutorServiceDemo.java

@@ -6,22 +6,22 @@ import java.util.concurrent.TimeUnit;
 
 public class ExecutorServiceDemo {
 
-	ExecutorService executor = Executors.newFixedThreadPool(10);
+    ExecutorService executor = Executors.newFixedThreadPool(10);
 
-	public void execute() {
+    public void execute() {
 
-		executor.submit(() -> {
+        executor.submit(() -> {
-			new Task();
+            new Task();
-		});
+        });
 
-		executor.shutdown();
+        executor.shutdown();
-		executor.shutdownNow();
+        executor.shutdownNow();
-		try {
+        try {
-			executor.awaitTermination(20l, TimeUnit.NANOSECONDS);
+            executor.awaitTermination(20l, TimeUnit.NANOSECONDS);
-		} catch (InterruptedException e) {
+        } catch (InterruptedException e) {
-			e.printStackTrace();
+            e.printStackTrace();
-		}
+        }
 
-	}
+    }
 
 }

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

@@ -9,36 +9,36 @@ import java.util.concurrent.TimeoutException;
 
 public class FutureDemo {
 
-	public String invoke() {
+    public String invoke() {
 
-		String str = null;
+        String str = null;
 
-		ExecutorService executorService = Executors.newFixedThreadPool(10);
+        ExecutorService executorService = Executors.newFixedThreadPool(10);
 
-		Future<String> future = executorService.submit(() -> {
+        Future<String> future = executorService.submit(() -> {
-			// Task
+            // Task
-			Thread.sleep(10000l);
+            Thread.sleep(10000l);
-			return "Hellow world";
+            return "Hellow world";
-		});
+        });
 
-		future.cancel(false);
+        future.cancel(false);
 
-		try {
+        try {
-			future.get(20, TimeUnit.SECONDS);
+            future.get(20, TimeUnit.SECONDS);
-		} catch (InterruptedException | ExecutionException | TimeoutException e1) {
+        } catch (InterruptedException | ExecutionException | TimeoutException e1) {
-			e1.printStackTrace();
+            e1.printStackTrace();
-		}
+        }
 
-		if (future.isDone() && !future.isCancelled()) {
+        if (future.isDone() && !future.isCancelled()) {
-			try {
+            try {
-				str = future.get();
+                str = future.get();
-			} catch (InterruptedException | ExecutionException e) {
+            } catch (InterruptedException | ExecutionException e) {
-				e.printStackTrace();
+                e.printStackTrace();
-			}
+            }
-		}
+        }
 
-		return str;
+        return str;
 
-	}
+    }
 
 }

core-java/src/main/java/com/baeldung/concurrent/threadfactory/BaeldungThreadFactory.java

@@ -4,20 +4,20 @@ import java.util.concurrent.ThreadFactory;
 
 public class BaeldungThreadFactory implements ThreadFactory {
 
-	private int threadId;
+    private int threadId;
-	private String name;
+    private String name;
 
-	public BaeldungThreadFactory(String name) {
+    public BaeldungThreadFactory(String name) {
-		threadId = 1;
+        threadId = 1;
-		this.name = name;
+        this.name = name;
-	}
+    }
 
-	@Override
+    @Override
-	public Thread newThread(Runnable r) {
+    public Thread newThread(Runnable r) {
-		Thread t = new Thread(r, name + "-Thread_" + threadId);
+        Thread t = new Thread(r, name + "-Thread_" + threadId);
-		System.out.println("created new thread with id : " + threadId + " and name : " + t.getName());
+        System.out.println("created new thread with id : " + threadId + " and name : " + t.getName());
-		threadId++;
+        threadId++;
-		return t;
+        return t;
-	}
+    }
 
 }

core-java/src/main/java/com/baeldung/concurrent/threadfactory/Task.java

@@ -2,9 +2,9 @@ package com.baeldung.concurrent.threadfactory;
 
 public class Task implements Runnable {
 
-	@Override
+    @Override
-	public void run() {
+    public void run() {
-		// task details
+        // task details
-	}
+    }
-	
+
 }

core-java/src/main/java/com/baeldung/concurrent/volatilekeyword/SharedObject.java

@@ -0,0 +1,13 @@
+package com.baeldung.concurrent.volatilekeyword;
+
+
+public class SharedObject {
+    private volatile int count=0;
+
+    void increamentCount(){
+        count++;
+    }
+    public int  getCount(){
+        return count;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/adapter/AdapterPatternDriver.java

@@ -0,0 +1,13 @@
+package com.baeldung.designpatterns.adapter;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class AdapterPatternDriver {
+    
+    public static void main(String args[]) {
+        LuxuryCarsSpeedAdapter luxuryCars = new LuxuryCarsSpeedAdapterImpl();
+        LOG.info("Bugatti Veyron Super Sport's top speed is " + luxuryCars.bugattiVeyronInKMPH() + " Kmph.");
+        LOG.info("McLaren F1 top speed is " + luxuryCars.mcLarenInKMPH() + " Kmph.");
+        LOG.info("Aston Martin One-77 top speed is " + luxuryCars.astonMartinInKMPH() + " Kmph.");
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/adapter/LuxuryCarsSpeed.java

@@ -0,0 +1,15 @@
+package com.baeldung.designpatterns.adapter;
+
+public class LuxuryCarsSpeed {
+    public double bugattiVeyronInMPH() {
+        return 268;
+    }
+    
+    public double mcLarenInMPH() {
+        return 241;
+    }
+    
+    public double astonMartinInMPH() {
+        return 220;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/adapter/LuxuryCarsSpeedAdapter.java

@@ -0,0 +1,7 @@
+package com.baeldung.designpatterns.adapter;
+
+public interface LuxuryCarsSpeedAdapter {
+    public double bugattiVeyronInKMPH();
+    public double mcLarenInKMPH();
+    public double astonMartinInKMPH();
+}

core-java/src/main/java/com/baeldung/designpatterns/adapter/LuxuryCarsSpeedAdapterImpl.java

@@ -0,0 +1,26 @@
+package com.baeldung.designpatterns.adapter;
+
+public class LuxuryCarsSpeedAdapterImpl extends LuxuryCarsSpeed implements LuxuryCarsSpeedAdapter {
+
+    @Override
+    public double bugattiVeyronInKMPH() {
+        double mph = super.bugattiVeyronInMPH();
+        return convertMPHtoKMPH(mph);
+    }
+
+    @Override
+    public double mcLarenInKMPH() {
+        double mph = super.mcLarenInMPH();
+        return convertMPHtoKMPH(mph);
+    }
+
+    @Override
+    public double astonMartinInKMPH() {
+        double mph = super.astonMartinInMPH();
+        return convertMPHtoKMPH(mph);
+    }
+
+    private double convertMPHtoKMPH(double mph) {
+        return mph * 1.60934;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Blue.java

@@ -0,0 +1,12 @@
+package com.baeldung.designpatterns.bridge;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class Blue implements Color {
+
+    @Override
+    public void fillColor() { 
+        LOG.info("Color : Blue");
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/BridgePatternDriver.java

@@ -0,0 +1,14 @@
+package com.baeldung.designpatterns.bridge;
+
+public class BridgePatternDriver {
+
+    public static void main(String[] args) {
+        //a square with red color
+        Shape square = new Square(new Red());
+        square.drawShape();
+        
+        //a triangle with blue color
+        Shape triangle = new Triangle(new Blue());
+        triangle.drawShape();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Color.java

@@ -0,0 +1,5 @@
+package com.baeldung.designpatterns.bridge;
+
+public interface Color {
+    public void fillColor();
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Red.java

@@ -0,0 +1,12 @@
+package com.baeldung.designpatterns.bridge;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class Red implements Color {
+
+    @Override
+    public void fillColor() {
+        LOG.info("Color : Red");
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Shape.java

@@ -0,0 +1,11 @@
+package com.baeldung.designpatterns.bridge;
+
+public abstract class Shape {
+    protected Color color;
+    
+    public Shape(Color color) {
+        this.color = color;
+    }
+    
+    abstract public void drawShape();
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Square.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.bridge;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class Square extends Shape {
+
+    public Square(Color color) {
+        super(color);
+    }
+
+    @Override
+    public void drawShape() {
+        LOG.info("Square drawn. ");
+        color.fillColor();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/bridge/Triangle.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.bridge;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class Triangle extends Shape {
+
+    public Triangle(Color color) {
+        super(color);
+    }
+
+    @Override
+    public void drawShape() {
+        LOG.info("Triangle drawn. ");
+        color.fillColor();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/BubbleLights.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.decorator;
+
+public class BubbleLights extends TreeDecorator {
+
+    public BubbleLights(ChristmasTree tree) {
+        super(tree);
+    }
+    
+    public String decorate() {
+        return super.decorate() + decorateWithBubbleLights();
+    }
+    
+    private String decorateWithBubbleLights() {
+        return " with Bubble Lights";
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/ChristmasTree.java

@@ -0,0 +1,5 @@
+package com.baeldung.designpatterns.decorator;
+
+public interface ChristmasTree {
+    public String decorate();
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/ChristmasTreeImpl.java

@@ -0,0 +1,10 @@
+package com.baeldung.designpatterns.decorator;
+
+public class ChristmasTreeImpl implements ChristmasTree {
+
+    @Override
+    public String decorate() {
+        return "Christmas tree";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/DecoratorPatternDriver.java

@@ -0,0 +1,20 @@
+package com.baeldung.designpatterns.decorator;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+
+public class DecoratorPatternDriver {
+
+    public static void main(String[] args) {
+        //christmas tree with just one Garland
+        ChristmasTree tree1 = new Garland(new ChristmasTreeImpl());
+        LOG.info(tree1.decorate());
+        
+        //christmas tree with two Garlands and one Bubble lights
+        ChristmasTree tree2 = new BubbleLights(new Garland(
+          new Garland(new ChristmasTreeImpl()))
+        );
+        LOG.info(tree2.decorate());
+        
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/Garland.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.decorator;
+
+public class Garland extends TreeDecorator {
+
+    public Garland(ChristmasTree tree) {
+        super(tree);
+    }
+    
+    public String decorate() {
+        return super.decorate() + decorateWithGarland();
+    }
+
+    private String decorateWithGarland() {
+        return " with Garland";
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/decorator/TreeDecorator.java

@@ -0,0 +1,15 @@
+package com.baeldung.designpatterns.decorator;
+
+public abstract class TreeDecorator implements ChristmasTree {
+    private ChristmasTree tree;
+    
+    public TreeDecorator(ChristmasTree tree) {
+        this.tree = tree;
+    }
+    
+    @Override
+    public String decorate() {
+        return tree.decorate();
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/proxy/ExpensiveObject.java

@@ -0,0 +1,5 @@
+package com.baeldung.designpatterns.proxy;
+
+public interface ExpensiveObject {
+    public void process();
+}

core-java/src/main/java/com/baeldung/designpatterns/proxy/ExpensiveObjectImpl.java

@@ -0,0 +1,20 @@
+package com.baeldung.designpatterns.proxy;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;;
+
+public class ExpensiveObjectImpl implements ExpensiveObject {
+
+    public ExpensiveObjectImpl() {
+        heavyInitialConfiguration();
+    }
+    
+    @Override
+    public void process() {
+        LOG.info("processing complete.");
+    }
+    
+    private void heavyInitialConfiguration() {
+        LOG.info("Loading initial configuration...");
+    }
+    
+}

core-java/src/main/java/com/baeldung/designpatterns/proxy/ExpensiveObjectProxy.java

@@ -0,0 +1,13 @@
+package com.baeldung.designpatterns.proxy;
+
+public class ExpensiveObjectProxy implements ExpensiveObject{
+    private static ExpensiveObject object;
+
+    @Override
+    public void process() {
+        if(object == null) {
+            object = new ExpensiveObjectImpl();
+        }
+        object.process();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/proxy/ProxyPatternDriver.java

@@ -0,0 +1,9 @@
+package com.baeldung.designpatterns.proxy;
+
+public class ProxyPatternDriver {
+    public static void main(String[] args) {
+        ExpensiveObject object = new ExpensiveObjectProxy();
+        object.process();
+        object.process();
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/singleton/ClassSingleton.java

@@ -0,0 +1,28 @@
+package com.baeldung.designpatterns.singleton;
+
+public class ClassSingleton {
+
+    private static ClassSingleton INSTANCE;
+    private String info = "Initial class info";
+    
+    private ClassSingleton(){        
+    }
+    
+    public static ClassSingleton getInstance(){
+        if(INSTANCE == null){
+            INSTANCE = new ClassSingleton();
+        }
+        
+        return INSTANCE;
+    }
+    
+    // getters and setters
+    
+    public String getInfo() {
+        return info;
+    }
+    
+    public void setInfo(String info) {
+        this.info = info;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/singleton/EnumSingleton.java

@@ -0,0 +1,26 @@
+package com.baeldung.designpatterns.singleton;
+
+public enum EnumSingleton {
+    
+    INSTANCE("Initial enum info"); //Name of the single instance
+    
+    private String info;
+    
+    private EnumSingleton(String info) {
+        this.info = info;
+    }
+    
+    public EnumSingleton getInstance(){
+        return INSTANCE;
+    }
+    
+    //getters and setters
+
+    public String getInfo() {
+        return info;
+    }
+
+    public void setInfo(String info) {
+        this.info = info;
+    }    
+}

core-java/src/main/java/com/baeldung/designpatterns/singleton/Sandbox.java

@@ -0,0 +1,32 @@
+package com.baeldung.designpatterns.singleton;
+
+public class Sandbox {
+
+    public static void main(String[] args) {
+        
+        //Class singleton
+        
+        ClassSingleton classSingleton1 = ClassSingleton.getInstance();
+        //OurSingleton object1 = new OurSingleton(); // The constructor OurSingleton() is not visible
+        
+        System.out.println(classSingleton1.getInfo()); //Initial class info
+        
+        ClassSingleton classSingleton2 = ClassSingleton.getInstance();
+        classSingleton2.setInfo("New class info");
+        
+        System.out.println(classSingleton1.getInfo()); //New class info
+        System.out.println(classSingleton2.getInfo()); //New class info
+        
+        //Enum singleton
+        
+        EnumSingleton enumSingleton1 = EnumSingleton.INSTANCE.getInstance();
+        
+        System.out.println(enumSingleton1.getInfo()); //Initial enum info
+        
+        EnumSingleton enumSingleton2 = EnumSingleton.INSTANCE.getInstance();
+        enumSingleton2.setInfo("New enum info");
+        
+        System.out.println(enumSingleton1.getInfo()); //New enum info
+        System.out.println(enumSingleton2.getInfo()); //New enum info
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/util/LogerUtil.java

@@ -0,0 +1,35 @@
+package com.baeldung.designpatterns.util;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Properties;
+
+import org.apache.log4j.Logger;
+import org.apache.log4j.PropertyConfigurator;
+
+public class LogerUtil {
+
+    public final static Logger LOG = Logger.getLogger("GLOBAL");
+    
+    static {
+    	configuration();
+    }
+    
+    private static void configuration() {
+    	Properties props = new Properties();
+    	try {
+			props.load(
+			  new BufferedReader(
+			    new InputStreamReader(
+			      LogerUtil.class.getResourceAsStream("/log4jstructuraldp.properties")
+			    )
+			  )
+			);
+		} catch (IOException e) {
+			System.out.println("log4jstructuraldp.properties file not configured properly");
+			System.exit(0);
+		}
+    	PropertyConfigurator.configure(props);
+    }
+}

core-java/src/main/java/com/baeldung/filesystem/jndi/LookupFSJNDI.java

@@ -14,26 +14,25 @@ public class LookupFSJNDI {
         super();
         init();
     }
-    
+
     private void init() throws NamingException {
         Hashtable<String, String> env = new Hashtable<String, String>();
-        
+
-        env.put (Context.INITIAL_CONTEXT_FACTORY,
+        env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.fscontext.RefFSContextFactory");
-          "com.sun.jndi.fscontext.RefFSContextFactory");
         // URI to namespace (actual directory)
         env.put(Context.PROVIDER_URL, "file:./src/test/resources");
-        
+
         ctx = new InitialContext(env);
     }
 
     public InitialContext getCtx() {
         return ctx;
     }
-    
+
     public File getFile(String fileName) {
         File file;
         try {
-            file = (File)getCtx().lookup(fileName);
+            file = (File) getCtx().lookup(fileName);
         } catch (NamingException e) {
             file = null;
         }

core-java/src/main/java/com/baeldung/hashcode/application/Application.java

@@ -1,23 +0,0 @@
-package com.baeldung.application;
-
-import com.baeldung.entities.User;
-import java.util.HashMap;
-import java.util.Map;
-
-public class Application {
-
-    public static void main(String[] args) {
-        Map<User, User> users = new HashMap<>();
-        User user1 = new User(1L, "John", "john@domain.com");
-        User user2 = new User(2L, "Jennifer", "jennifer@domain.com");
-        User user3 = new User(3L, "Mary", "mary@domain.com");
-
-        users.put(user1, user1);
-        users.put(user2, user2);
-        users.put(user3, user3);
-
-        if (users.containsKey(user1)) {
-            System.out.print("User found in the collection");
-        }
-    }
-}

core-java/src/main/java/com/baeldung/hashcode/entities/User.java

@@ -1,4 +1,4 @@
-package com.baeldung.entities;
+package com.baeldung.hashcode.entities;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -18,13 +18,16 @@ public class User {
 
     @Override
     public boolean equals(Object o) {
-        if (this == o) return true;
+        if (this == o)
-        if (o == null) return false;
+            return true;
-        if (this.getClass() != o.getClass()) return false;
+        if (o == null)
+            return false;
+        if (this.getClass() != o.getClass())
+            return false;
         User user = (User) o;
         return id != user.id && (!name.equals(user.name) && !email.equals(user.email));
     }
-    	
+
     @Override
     public int hashCode() {
         int hash = 7;

core-java/src/main/java/com/baeldung/jmx/JMXTutorialMainlauncher.java

@@ -10,7 +10,6 @@ public class JMXTutorialMainlauncher {
 
     private static final Logger LOG = LoggerFactory.getLogger(JMXTutorialMainlauncher.class);
 
-
     public static void main(String[] args) {
         // TODO Auto-generated method stub
 

core-java/src/main/java/com/baeldung/networking/cookies/PersistentCookieStore.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.networking.cookies;
+package com.baeldung.networking.cookies;
 
 import java.net.*;
 import java.util.List;

core-java/src/main/java/com/baeldung/networking/cookies/ProxyAcceptCookiePolicy.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.networking.cookies;
+package com.baeldung.networking.cookies;
 
 import java.net.*;
 

core-java/src/main/java/com/baeldung/networking/udp/EchoClient.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.networking.udp;
+package com.baeldung.networking.udp;
 
 import java.io.IOException;
 import java.net.DatagramPacket;

core-java/src/main/java/com/baeldung/networking/udp/EchoServer.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.networking.udp;
+package com.baeldung.networking.udp;
 
 import java.io.IOException;
 import java.net.DatagramPacket;

core-java/src/main/java/com/baeldung/networking/udp/broadcast/BroadcastingClient.java

@@ -0,0 +1,85 @@
+package com.baeldung.networking.udp.broadcast;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class BroadcastingClient {
+    private DatagramSocket socket;
+    private InetAddress address;
+    private int expectedServerCount;
+    private byte[] buf;
+
+    public BroadcastingClient(int expectedServerCount) throws Exception {
+        this.expectedServerCount = expectedServerCount;
+        this.address = InetAddress.getByName("255.255.255.255");
+    }
+
+    public int discoverServers(String msg) throws IOException {
+        initializeSocketForBroadcasting();
+        copyMessageOnBuffer(msg);
+
+        // When we want to broadcast not just to local network, call listAllBroadcastAddresses() and execute broadcastPacket for each value.
+        broadcastPacket(address);
+
+        return receivePackets();
+    }
+
+    List<InetAddress> listAllBroadcastAddresses() throws SocketException {
+        List<InetAddress> broadcastList = new ArrayList<>();
+        Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
+        while (interfaces.hasMoreElements()) {
+            NetworkInterface networkInterface = interfaces.nextElement();
+
+            if (networkInterface.isLoopback() || !networkInterface.isUp()) {
+                continue;
+            }
+
+            broadcastList.addAll(networkInterface.getInterfaceAddresses()
+                .stream()
+                .filter(address -> address.getBroadcast() != null)
+                .map(address -> address.getBroadcast())
+                .collect(Collectors.toList()));
+        }
+        return broadcastList;
+    }
+
+    private void initializeSocketForBroadcasting() throws SocketException {
+        socket = new DatagramSocket();
+        socket.setBroadcast(true);
+    }
+
+    private void copyMessageOnBuffer(String msg) {
+        buf = msg.getBytes();
+    }
+
+    private void broadcastPacket(InetAddress address) throws IOException {
+        DatagramPacket packet = new DatagramPacket(buf, buf.length, address, 4445);
+        socket.send(packet);
+    }
+
+    private int receivePackets() throws IOException {
+        int serversDiscovered = 0;
+        while (serversDiscovered != expectedServerCount) {
+            receivePacket();
+            serversDiscovered++;
+        }
+        return serversDiscovered;
+    }
+
+    private void receivePacket() throws IOException {
+        DatagramPacket packet = new DatagramPacket(buf, buf.length);
+        socket.receive(packet);
+    }
+
+    public void close() {
+        socket.close();
+    }
+}

core-java/src/main/java/com/baeldung/networking/udp/broadcast/BroadcastingEchoServer.java

@@ -0,0 +1,44 @@
+package com.baeldung.networking.udp.broadcast;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+
+public class BroadcastingEchoServer extends Thread {
+
+    protected DatagramSocket socket = null;
+    protected boolean running;
+    protected byte[] buf = new byte[256];
+
+    public BroadcastingEchoServer() throws IOException {
+        socket = new DatagramSocket(null);
+        socket.setReuseAddress(true);
+        socket.bind(new InetSocketAddress(4445));
+    }
+
+    public void run() {
+        running = true;
+
+        while (running) {
+            try {
+                DatagramPacket packet = new DatagramPacket(buf, buf.length);
+                socket.receive(packet);
+                InetAddress address = packet.getAddress();
+                int port = packet.getPort();
+                packet = new DatagramPacket(buf, buf.length, address, port);
+                String received = new String(packet.getData(), 0, packet.getLength());
+                if (received.equals("end")) {
+                    running = false;
+                    continue;
+                }
+                socket.send(packet);
+            } catch (IOException e) {
+                e.printStackTrace();
+                running = false;
+            }
+        }
+        socket.close();
+    }
+}

core-java/src/main/java/com/baeldung/networking/udp/multicast/MulticastEchoServer.java

@@ -0,0 +1,41 @@
+package com.baeldung.networking.udp.multicast;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.InetAddress;
+import java.net.MulticastSocket;
+
+public class MulticastEchoServer extends Thread {
+
+    protected MulticastSocket socket = null;
+    protected byte[] buf = new byte[256];
+    protected InetAddress group = null;
+
+    public MulticastEchoServer() throws IOException {
+        socket = new MulticastSocket(4446);
+        socket.setReuseAddress(true);
+        group = InetAddress.getByName("230.0.0.0");
+        socket.joinGroup(group);
+    }
+
+    public void run() {
+        try {
+            while (true) {
+                DatagramPacket packet = new DatagramPacket(buf, buf.length);
+                socket.receive(packet);
+                InetAddress address = packet.getAddress();
+                int port = packet.getPort();
+                packet = new DatagramPacket(buf, buf.length, address, port);
+                String received = new String(packet.getData(), 0, packet.getLength());
+                if (received.equals("end")) {
+                    break;
+                }
+                socket.send(packet);
+            }
+            socket.leaveGroup(group);
+            socket.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}

core-java/src/main/java/com/baeldung/networking/udp/multicast/MulticastingClient.java

@@ -0,0 +1,53 @@
+package com.baeldung.networking.udp.multicast;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+
+public class MulticastingClient {
+    private DatagramSocket socket;
+    private InetAddress group;
+    private int expectedServerCount;
+    private byte[] buf;
+
+    public MulticastingClient(int expectedServerCount) throws Exception {
+        this.expectedServerCount = expectedServerCount;
+        this.socket = new DatagramSocket();
+        this.group = InetAddress.getByName("230.0.0.0");
+    }
+
+    public int discoverServers(String msg) throws IOException {
+        copyMessageOnBuffer(msg);
+        multicastPacket();
+
+        return receivePackets();
+    }
+
+    private void copyMessageOnBuffer(String msg) {
+        buf = msg.getBytes();
+    }
+
+    private void multicastPacket() throws IOException {
+        DatagramPacket packet = new DatagramPacket(buf, buf.length, group, 4446);
+        socket.send(packet);
+    }
+
+    private int receivePackets() throws IOException {
+        int serversDiscovered = 0;
+        while (serversDiscovered != expectedServerCount) {
+            receivePacket();
+            serversDiscovered++;
+        }
+        return serversDiscovered;
+    }
+
+    private void receivePacket() throws IOException {
+        DatagramPacket packet = new DatagramPacket(buf, buf.length);
+        socket.receive(packet);
+    }
+
+    public void close() {
+        socket.close();
+    }
+}

core-java/src/main/java/com/baeldung/socket/EchoClient.java

@@ -8,9 +8,8 @@ import java.net.*;
 
 public class EchoClient {
 
-
     private static final Logger LOG = LoggerFactory.getLogger(EchoClient.class);
-    
+
     private Socket clientSocket;
     private PrintWriter out;
     private BufferedReader in;

core-java/src/main/java/com/baeldung/stream/InfiniteStreams.java

@@ -1,6 +1,5 @@
 package com.baeldung.stream;
 
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 

core-java/src/main/java/com/baeldung/string/StringHelper.java

@@ -12,15 +12,10 @@ class StringHelper {
     }
 
     static String removeLastCharOptional(String s) {
-        return Optional.ofNullable(s)
+        return Optional.ofNullable(s).filter(str -> str.length() != 0).map(str -> str.substring(0, str.length() - 1)).orElse(s);
-            .filter(str -> str.length() != 0)
-            .map(str -> str.substring(0, str.length() - 1))
-            .orElse(s);
     }
 
     static String removeLastCharRegexOptional(String s) {
-        return Optional.ofNullable(s)
+        return Optional.ofNullable(s).map(str -> str.replaceAll(".$", "")).orElse(s);
-            .map(str -> str.replaceAll(".$", ""))
-            .orElse(s);
     }
 }

core-java/src/main/java/com/baeldung/stringtokenizer/MyTokenizer.java

@@ -25,11 +25,7 @@ public class MyTokenizer {
     }
 
     public List<String> getTokensWithCollection(String str) {
-        return Collections
+        return Collections.list(new StringTokenizer(str, ",")).stream().map(token -> (String) token).collect(Collectors.toList());
-          .list(new StringTokenizer(str, ","))
-          .stream()
-          .map(token -> (String) token)
-          .collect(Collectors.toList());
     }
 
     public List<String> getTokensFromFile(String path, String delim) {

core-java/src/main/java/com/baeldung/temporaladjuster/CustomTemporalAdjuster.java

@@ -11,12 +11,12 @@ public class CustomTemporalAdjuster implements TemporalAdjuster {
     @Override
     public Temporal adjustInto(Temporal temporal) {
         switch (DayOfWeek.of(temporal.get(ChronoField.DAY_OF_WEEK))) {
-            case FRIDAY:
+        case FRIDAY:
-                return temporal.plus(3, ChronoUnit.DAYS);
+            return temporal.plus(3, ChronoUnit.DAYS);
-            case SATURDAY:
+        case SATURDAY:
-                return temporal.plus(2, ChronoUnit.DAYS);
+            return temporal.plus(2, ChronoUnit.DAYS);
-            default:
+        default:
-                return temporal.plus(1, ChronoUnit.DAYS);
+            return temporal.plus(1, ChronoUnit.DAYS);
         }
     }
 }

core-java/src/main/java/com/baeldung/transferqueue/Consumer.java

@@ -9,7 +9,6 @@ import java.util.concurrent.atomic.AtomicInteger;
 public class Consumer implements Runnable {
     private static final Logger LOG = LoggerFactory.getLogger(Consumer.class);
 
-    
     private final TransferQueue<String> transferQueue;
     private final String name;
     private final int numberOfMessagesToConsume;

core-java/src/main/resources/log4jstructuraldp.properties

@@ -0,0 +1,9 @@
+
+# Root logger 
+log4j.rootLogger=INFO, file, stdout
+
+# Write to console
+log4j.appender.stdout=org.apache.log4j.ConsoleAppender
+log4j.appender.stdout.Target=System.out
+log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
+log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

core-java/src/test/java/com/baeldung/concurrent/accumulator/LongAccumulatorUnitTest.java

@@ -15,28 +15,24 @@ public class LongAccumulatorUnitTest {
 
     @Test
     public void givenLongAccumulator_whenApplyActionOnItFromMultipleThrads_thenShouldProduceProperResult() throws InterruptedException {
-        //given
+        // given
         ExecutorService executorService = Executors.newFixedThreadPool(8);
         LongBinaryOperator sum = Long::sum;
         LongAccumulator accumulator = new LongAccumulator(sum, 0L);
         int numberOfThreads = 4;
         int numberOfIncrements = 100;
 
-        //when
+        // when
-        Runnable accumulateAction = () -> IntStream
+        Runnable accumulateAction = () -> IntStream.rangeClosed(0, numberOfIncrements).forEach(accumulator::accumulate);
-          .rangeClosed(0, numberOfIncrements)
-          .forEach(accumulator::accumulate);
 
         for (int i = 0; i < numberOfThreads; i++) {
             executorService.execute(accumulateAction);
         }
 
-
+        // then
-        //then
         executorService.awaitTermination(500, TimeUnit.MILLISECONDS);
         executorService.shutdown();
         assertEquals(accumulator.get(), 20200);
 
-
     }
 }

core-java/src/test/java/com/baeldung/concurrent/volatilekeyword/SharedObjectManualTest.java

@@ -0,0 +1,71 @@
+package com.baeldung.concurrent.volatilekeyword;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import static junit.framework.Assert.assertEquals;
+
+public class SharedObjectManualTest {
+
+    private SharedObject sharedObject;
+    private int valueReadByThread2;
+    private int valueReadByThread3;
+
+    @Before
+    public void setUp() {
+        sharedObject = new SharedObject();
+    }
+
+    @Test
+    public void whenOneThreadWrites_thenVolatileReadsFromMainMemory() throws InterruptedException {
+        Thread writer = new Thread(() -> sharedObject.increamentCount());
+        writer.start();
+
+
+        Thread readerOne = new Thread(() -> {
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+            valueReadByThread2 = sharedObject.getCount();
+        });
+        readerOne.start();
+
+        Thread readerTwo = new Thread(() -> {
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+            valueReadByThread3 = sharedObject.getCount();
+        });
+        readerTwo.start();
+
+        assertEquals(1, valueReadByThread2);
+        assertEquals(1, valueReadByThread3);
+
+    }
+
+    @Test
+    public void whenTwoThreadWrites_thenVolatileReadsFromMainMemory() throws InterruptedException {
+        Thread writerOne = new Thread(() -> sharedObject.increamentCount());
+        writerOne.start();
+        Thread.sleep(100);
+
+        Thread writerTwo = new Thread(() -> sharedObject.increamentCount());
+        writerTwo.start();
+        Thread.sleep(100);
+
+        Thread readerOne = new Thread(() -> valueReadByThread2 = sharedObject.getCount());
+        readerOne.start();
+
+        Thread readerTwo = new Thread(() -> valueReadByThread3 = sharedObject.getCount());
+        readerTwo.start();
+
+        assertEquals(2, valueReadByThread2);
+        assertEquals(2, valueReadByThread3);
+
+    }
+}

core-java/src/test/java/com/baeldung/designpatterns/AdapterPatternIntegrationTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.designpatterns;
+
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import com.baeldung.designpatterns.adapter.LuxuryCarsSpeedAdapter;
+import com.baeldung.designpatterns.adapter.LuxuryCarsSpeedAdapterImpl;
+
+public class AdapterPatternIntegrationTest {
+    @Test
+    public void givenLuxuryCarsAdapter_WhenConvertingMPHToKMPH_thenSuccessfullyConverted() {
+        LuxuryCarsSpeedAdapter luxuryCars = new LuxuryCarsSpeedAdapterImpl();
+        assertEquals(luxuryCars.bugattiVeyronInKMPH(), 431.30312, 0.00001);
+        assertEquals(luxuryCars.mcLarenInKMPH(), 387.85094, 0.00001);
+        assertEquals(luxuryCars.astonMartinInKMPH(), 354.0548, 0.00001);
+    }
+}
+

core-java/src/test/java/com/baeldung/designpatterns/BridgePatternIntegrationTest.java

@@ -0,0 +1,52 @@
+package com.baeldung.designpatterns;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.List;
+
+import org.apache.log4j.spi.LoggingEvent;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.designpatterns.bridge.Blue;
+import com.baeldung.designpatterns.bridge.Red;
+import com.baeldung.designpatterns.bridge.Shape;
+import com.baeldung.designpatterns.bridge.Square;
+import com.baeldung.designpatterns.bridge.Triangle;
+
+public class BridgePatternIntegrationTest {
+    public static TestAppenderDP appender;
+    
+    @Before
+    public void setUp() {
+        appender = new TestAppenderDP();
+        LOG.addAppender(appender);
+    }
+    
+    @Test
+    public void whenBridgePatternInvoked_thenConfigSuccess() {
+        //a square with red color
+        Shape square = new Square(new Red());
+        square.drawShape();
+        
+        //a triangle with blue color
+        Shape triangle = new Triangle(new Blue());
+        triangle.drawShape();
+
+        final List<LoggingEvent> log = appender.getLog();
+        
+        assertThat((String) log.get(0).getMessage(), is("Square drawn. "));
+        assertThat((String) log.get(1).getMessage(), is("Color : Red"));
+        assertThat((String) log.get(2).getMessage(), is("Triangle drawn. "));
+        assertThat((String) log.get(3).getMessage(), is("Color : Blue"));
+    }
+    
+    @After
+    public void tearDown() {
+        LOG.removeAppender(appender);
+    }
+}
+

core-java/src/test/java/com/baeldung/designpatterns/DecoratorPatternIntegrationTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.designpatterns;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import com.baeldung.designpatterns.decorator.BubbleLights;
+import com.baeldung.designpatterns.decorator.ChristmasTree;
+import com.baeldung.designpatterns.decorator.ChristmasTreeImpl;
+import com.baeldung.designpatterns.decorator.Garland;
+
+public class DecoratorPatternIntegrationTest {
+    private ChristmasTree tree;
+    
+    @Test
+    public void givenDecoratorPattern_WhenDecoratorsInjectedAtRuntime_thenConfigSuccess() {
+        //christmas tree with just one Garland
+        tree = new Garland(new ChristmasTreeImpl());
+        assertEquals(tree.decorate(), "Christmas tree with Garland");
+        
+        //christmas tree with two Garlands and one Bubble lights
+        tree = new BubbleLights(new Garland(
+          new Garland(new ChristmasTreeImpl()))
+        );
+        assertEquals(tree.decorate(), "Christmas tree with Garland with Garland with Bubble Lights");
+    }
+}
+

core-java/src/test/java/com/baeldung/designpatterns/ProxyPatternIntegrationTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.designpatterns;
+
+import static com.baeldung.designpatterns.util.LogerUtil.LOG;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.List;
+
+import org.apache.log4j.spi.LoggingEvent;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.designpatterns.proxy.ExpensiveObject;
+import com.baeldung.designpatterns.proxy.ExpensiveObjectProxy;
+
+public class ProxyPatternIntegrationTest {
+    public static TestAppenderDP appender;
+    
+    @Before
+    public void setUp() {
+        appender = new TestAppenderDP();
+        LOG.addAppender(appender);
+    }
+    
+    @Test
+    public void givenExpensiveObjectProxy_WhenObjectInitialized_thenInitializedOnlyOnce() {
+        ExpensiveObject object = new ExpensiveObjectProxy();
+        object.process();
+        object.process();
+
+        final List<LoggingEvent> log = appender.getLog();
+        
+        assertThat((String) log.get(0).getMessage(), is("Loading initial configuration..."));
+        assertThat((String) log.get(1).getMessage(), is("processing complete."));
+        assertThat((String) log.get(2).getMessage(), is("processing complete."));
+    }
+    
+    @After
+    public void tearDown() {
+        LOG.removeAppender(appender);
+    }
+}
+

core-java/src/test/java/com/baeldung/designpatterns/TestAppenderDP.java

@@ -0,0 +1,29 @@
+package com.baeldung.designpatterns;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.log4j.AppenderSkeleton;
+import org.apache.log4j.spi.LoggingEvent;
+
+public class TestAppenderDP extends AppenderSkeleton {
+    private final List<LoggingEvent> log = new ArrayList<LoggingEvent>();
+
+    @Override
+    public boolean requiresLayout() {
+        return false;
+    }
+
+    @Override
+    protected void append(final LoggingEvent loggingEvent) {
+        log.add(loggingEvent);
+    }
+
+    @Override
+    public void close() {
+    }
+
+    public List<LoggingEvent> getLog() {
+        return new ArrayList<LoggingEvent>(log);
+    }
+}

core-java/src/test/java/com/baeldung/hashcode/application/ApplicationTest.java

@@ -1,30 +1,26 @@
-package com.baeldung.application;
+package com.baeldung.hashcode.application;
 
-import org.junit.After;
+import com.baeldung.hashcode.entities.User;
-import org.junit.Before;
 import org.junit.Test;
-import java.io.ByteArrayOutputStream;
+
-import java.io.PrintStream;
+import java.util.HashMap;
-import static org.junit.Assert.assertEquals;
+import java.util.Map;
+
+import static org.junit.Assert.assertTrue;
 
 public class ApplicationTest {
 
-    private ByteArrayOutputStream outContent;
-
-    @Before
-    public void setUpPrintStreamInstance() throws Exception {
-        this.outContent = new ByteArrayOutputStream();
-        System.setOut(new PrintStream(outContent));
-    }
-
-    @After
-    public void tearDownByteArrayOutputStream() throws Exception {
-        outContent = null;
-    }
-
     @Test
     public void main_NoInputState_TextPrintedToConsole() throws Exception {
-        Application.main(new String[]{});
+        Map<User, User> users = new HashMap<>();
-        assertEquals("User found in the collection", outContent.toString());
+        User user1 = new User(1L, "John", "john@domain.com");
+        User user2 = new User(2L, "Jennifer", "jennifer@domain.com");
+        User user3 = new User(3L, "Mary", "mary@domain.com");
+
+        users.put(user1, user1);
+        users.put(user2, user2);
+        users.put(user3, user3);
+
+        assertTrue(users.containsKey(user1));
     }
 }

core-java/src/test/java/com/baeldung/hashcode/entities/UserTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.entities;
+package com.baeldung.hashcode.entities;
 
 import org.junit.After;
 import org.junit.Assert;
@@ -23,7 +23,7 @@ public class UserTest {
     }
 
     @Test
-    public void equals_EqualUserInstance_TrueAssertion(){
+    public void equals_EqualUserInstance_TrueAssertion() {
         Assert.assertTrue(user.equals(comparisonUser));
     }
 

core-java/src/test/java/com/baeldung/java8/lambda/exceptions/LambdaExceptionWrappersUnitTest.java

@@ -15,7 +15,6 @@ public class LambdaExceptionWrappersUnitTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(LambdaExceptionWrappersUnitTest.class);
 
-
     private List<Integer> integers;
 
     @Before

core-java/src/test/java/com/baeldung/javanetworking/uriurl/URIvsURLUnitTest.java

@@ -0,0 +1,78 @@
+package com.baeldung.javanetworking.uriurl;
+
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URL;
+import org.apache.commons.io.IOUtils;
+import static org.junit.Assert.*;
+import org.junit.Test;
+
+public class URIvsURLUnitTest {
+
+    @Test
+    public void whenCreatingURIs_thenSameInfo() throws URISyntaxException {
+        URI firstURI = new URI("somescheme://theuser:thepassword@someauthority:80/some/path?thequery#somefragment");
+        URI secondURI = new URI("somescheme", "theuser:thepassword", "someuthority", 80, "/some/path", "thequery", "somefragment");
+
+        assertEquals(firstURI.getScheme(), secondURI.getScheme());
+        assertEquals(firstURI.getPath(), secondURI.getPath());
+    }
+
+    @Test
+    public void whenCreatingURLs_thenSameInfo() throws MalformedURLException {
+        URL firstURL = new URL("http://theuser:thepassword@somehost:80/path/to/file?thequery#somefragment");
+        URL secondURL = new URL("http", "somehost", 80, "/path/to/file");
+
+        assertEquals(firstURL.getHost(), secondURL.getHost());
+        assertEquals(firstURL.getPath(), secondURL.getPath());
+    }
+
+    @Test
+    public void whenCreatingURI_thenCorrect() {
+        URI uri = URI.create("urn:isbn:1234567890");
+
+        assertNotNull(uri);
+    }
+
+    @Test(expected = MalformedURLException.class)
+    public void whenCreatingURLs_thenException() throws MalformedURLException {
+        URL theURL = new URL("otherprotocol://somehost/path/to/file");
+
+        assertNotNull(theURL);
+    }
+
+    @Test
+    public void givenObjects_whenConverting_thenCorrect() throws MalformedURLException, URISyntaxException {
+        String aURIString = "http://somehost:80/path?thequery";
+        URI uri = new URI(aURIString);
+        URL url = new URL(aURIString);
+
+        URL toURL = uri.toURL();
+        URI toURI = url.toURI();
+
+        assertNotNull(url);
+        assertNotNull(uri);
+        assertEquals(toURL.toString(), toURI.toString());
+    }
+
+    @Test(expected = MalformedURLException.class)
+    public void givenURI_whenConvertingToURL_thenException() throws MalformedURLException, URISyntaxException {
+        URI uri = new URI("somescheme://someauthority/path?thequery");
+
+        URL url = uri.toURL();
+
+        assertNotNull(url);
+    }
+
+    @Test
+    public void givenURL_whenGettingContents_thenCorrect() throws MalformedURLException, IOException {
+        URL url = new URL("http://courses.baeldung.com");
+
+        String contents = IOUtils.toString(url.openStream());
+        
+        assertTrue(contents.contains("<!DOCTYPE html>"));
+    }
+    
+}

core-java/src/test/java/com/baeldung/list/listoflist/ListOfListsUnitTest.java

@@ -29,12 +29,9 @@ public class ListOfListsUnitTest {
 
     @Test
     public void givenListOfLists_thenCheckNames() {
-        assertEquals("Pen 1", ((Pen) listOfLists.get(0)
+        assertEquals("Pen 1", ((Pen) listOfLists.get(0).get(0)).getName());
-          .get(0)).getName());
+        assertEquals("Pencil 1", ((Pencil) listOfLists.get(1).get(0)).getName());
-        assertEquals("Pencil 1", ((Pencil) listOfLists.get(1)
+        assertEquals("Rubber 1", ((Rubber) listOfLists.get(2).get(0)).getName());
-          .get(0)).getName());
-        assertEquals("Rubber 1", ((Rubber) listOfLists.get(2)
-          .get(0)).getName());
     }
 
     @SuppressWarnings("unchecked")
@@ -43,11 +40,9 @@ public class ListOfListsUnitTest {
 
         ((ArrayList<Pencil>) listOfLists.get(1)).remove(0);
         listOfLists.remove(1);
-        assertEquals("Rubber 1", ((Rubber) listOfLists.get(1)
+        assertEquals("Rubber 1", ((Rubber) listOfLists.get(1).get(0)).getName());
-          .get(0)).getName());
         listOfLists.remove(0);
-        assertEquals("Rubber 1", ((Rubber) listOfLists.get(0)
+        assertEquals("Rubber 1", ((Rubber) listOfLists.get(0).get(0)).getName());
-          .get(0)).getName());
     }
 
     @Test
@@ -67,11 +62,8 @@ public class ListOfListsUnitTest {
         list.add(pencils);
         list.add(rubbers);
 
-        assertEquals("Pen 1", ((Pen) list.get(0)
+        assertEquals("Pen 1", ((Pen) list.get(0).get(0)).getName());
-          .get(0)).getName());
+        assertEquals("Pencil 1", ((Pencil) list.get(1).get(0)).getName());
-        assertEquals("Pencil 1", ((Pencil) list.get(1)
+        assertEquals("Rubber 1", ((Rubber) list.get(2).get(0)).getName());
-          .get(0)).getName());
-        assertEquals("Rubber 1", ((Rubber) list.get(2)
-          .get(0)).getName());
     }
 }

core-java/src/test/java/com/baeldung/networking/udp/UDPIntegrationTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.networking.udp;
+package com.baeldung.networking.udp;
 
 import org.junit.After;
 import org.junit.Before;

core-java/src/test/java/com/baeldung/networking/udp/broadcast/BroadcastIntegrationTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.networking.udp.broadcast;
+
+import org.junit.After;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
+
+public class BroadcastIntegrationTest {
+    private BroadcastingClient client;
+
+    @Test
+    public void whenBroadcasting_thenDiscoverExpectedServers() throws Exception {
+        int expectedServers = 4;
+        initializeForExpectedServers(expectedServers);
+
+        int serversDiscovered = client.discoverServers("hello server");
+        assertEquals(expectedServers, serversDiscovered);
+    }
+
+    private void initializeForExpectedServers(int expectedServers) throws Exception {
+        for (int i = 0; i < expectedServers; i++) {
+            new BroadcastingEchoServer().start();
+        }
+
+        client = new BroadcastingClient(expectedServers);
+    }
+
+    @After
+    public void tearDown() throws IOException {
+        stopEchoServer();
+        client.close();
+    }
+
+    private void stopEchoServer() throws IOException {
+        client.discoverServers("end");
+    }
+}

core-java/src/test/java/com/baeldung/networking/udp/multicast/MulticastIntegrationTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.networking.udp.multicast;
+
+import org.junit.After;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
+
+public class MulticastIntegrationTest {
+    private MulticastingClient client;
+
+    @Test
+    public void whenBroadcasting_thenDiscoverExpectedServers() throws Exception {
+        int expectedServers = 4;
+        initializeForExpectedServers(expectedServers);
+
+        int serversDiscovered = client.discoverServers("hello server");
+        assertEquals(expectedServers, serversDiscovered);
+    }
+
+    private void initializeForExpectedServers(int expectedServers) throws Exception {
+        for (int i = 0; i < expectedServers; i++) {
+            new MulticastEchoServer().start();
+        }
+
+        client = new MulticastingClient(expectedServers);
+    }
+
+    @After
+    public void tearDown() throws IOException {
+        stopEchoServer();
+        client.close();
+    }
+
+    private void stopEchoServer() throws IOException {
+        client.discoverServers("end");
+    }
+}

core-java/src/test/java/com/baeldung/threadpool/CoreThreadPoolIntegrationTest.java

@@ -13,7 +13,6 @@ public class CoreThreadPoolIntegrationTest {
 
     private static final Logger LOG = LoggerFactory.getLogger(CoreThreadPoolIntegrationTest.class);
 
-
     @Test(timeout = 1000)
     public void whenCallingExecuteWithRunnable_thenRunnableIsExecuted() throws InterruptedException {
 

ejb/ejb-client/src/main/resources/jboss-ejb-client.properties

@@ -1,8 +1,8 @@
+endpoint.name=client-endpoint
+remote.connectionprovider.create.options.org.xnio.Options.SSL_ENABLED=false
 remote.connections=default
 remote.connection.default.host=127.0.0.1
 remote.connection.default.port=8080
 remote.connection.default.connect.options.org.xnio.Options.SASL_POLICY_NOANONYMOUS=false
-remote.connection.default.connect.options.org.xnio.Options.SASL_POLICY_NOPLAINTEXT=false
+remote.connection.default.username=myusername
-remote.connection.default.connect.options.org.xnio.Options.SASL_DISALLOWED_MECHANISMS=${host.auth:JBOSS-LOCAL-USER}
+remote.connection.default.password=mypassword
-remote.connection.default.username=testUser
-remote.connection.default.password=admin1234!