fix conflicts in pom.xml

.gitignore

@@ -1,3 +1,5 @@
+*/bin/*
+
 *.class
 
 # Package Files #
@@ -27,4 +29,15 @@ target/
 
 spring-openid/src/main/resources/application.properties
 .recommenders/
-/spring-hibernate4/nbproject/
+/spring-hibernate4/nbproject/
+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

.travis.yml

@@ -0,0 +1,23 @@
+language: java
+
+before_install: 
+  - echo "MAVEN_OPTS='-Xmx2048M -Xss128M -XX:+CMSClassUnloadingEnabled -XX:+UseG1GC -XX:-UseGCOverheadLimit'" > ~/.mavenrc
+
+install: travis_wait 60 mvn -q test -fae
+
+sudo: required
+
+jdk:
+  - oraclejdk8
+
+addons:
+  apt:
+    packages:
+      - oracle-java8-installer
+
+cache:
+  directories:
+  - .autoconf
+  - $HOME/.m2
+  
+

JGit/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [A Guide to JGit](http://www.baeldung.com/jgit)

JGit/pom.xml

@@ -6,6 +6,13 @@
     <version>1.0-SNAPSHOT</version>
     <packaging>jar</packaging>
     <url>http://maven.apache.org</url>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+     </parent>
+         
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>1.8</maven.compiler.source>
@@ -40,24 +47,5 @@
 		<artifactId>slf4j-simple</artifactId>
 		<version>1.7.21</version>
 	</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-compiler-plugin</artifactId>
-        <version>3.2</version>
-        <configuration>
-          <source>1.7</source>
-          <target>1.7</target>
-        </configuration>
-      </plugin>
-    </plugins>
-  </build>
 </project>

JGit/src/test/java/com/baeldung/jgit/JGitBugIntegrationTest.java

@@ -0,0 +1,31 @@
+import com.baeldung.jgit.helper.Helper;
+import org.eclipse.jgit.lib.ObjectLoader;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.junit.Test;
+import java.io.IOException;
+import static org.junit.Assert.assertNotNull;
+
+/**
+ * Tests which show issues with JGit that we reported upstream.
+ */
+public class JGitBugIntegrationTest {
+    @Test
+    public void testRevWalkDisposeClosesReader() throws IOException {
+        try (Repository repo = Helper.openJGitRepository()) {
+            try (ObjectReader reader = repo.newObjectReader()) {
+                try (RevWalk walk = new RevWalk(reader)) {
+                    walk.dispose();
+
+                    Ref head = repo.exactRef("refs/heads/master");
+                    System.out.println("Found head: " + head);
+
+                    ObjectLoader loader = reader.open(head.getObjectId());
+                    assertNotNull(loader);
+                }
+            }
+        }
+    }
+}

JGit/src/test/java/com/baeldung/jgit/JGitBugTest.java

@@ -1,31 +0,0 @@
-import com.baeldung.jgit.helper.Helper;
-import org.eclipse.jgit.lib.ObjectLoader;
-import org.eclipse.jgit.lib.ObjectReader;
-import org.eclipse.jgit.lib.Ref;
-import org.eclipse.jgit.lib.Repository;
-import org.eclipse.jgit.revwalk.RevWalk;
-import org.junit.Test;
-import java.io.IOException;
-import static org.junit.Assert.assertNotNull;
-
-/**
- * Tests which show issues with JGit that we reported upstream.
- */
-public class JGitBugTest {
-    @Test
-    public void testRevWalkDisposeClosesReader() throws IOException {
-        try (Repository repo = Helper.openJGitRepository()) {
-            try (ObjectReader reader = repo.newObjectReader()) {
-                try (RevWalk walk = new RevWalk(reader)) {
-                    walk.dispose();
-
-                    Ref head = repo.exactRef("refs/heads/master");
-                    System.out.println("Found head: " + head);
-
-                    ObjectLoader loader = reader.open(head.getObjectId());
-                    assertNotNull(loader);
-                }
-            }
-        }
-    }
-}

JGit/src/test/java/com/baeldung/jgit/porcelain/PorcelainTest.java

@@ -1,17 +0,0 @@
-package com.baeldung.jgit.porcelain;
-
-import org.junit.Test;
-
-public class PorcelainTest {
-    @Test
-    public void runSamples() throws Exception {
-        // simply call all the samples to see any severe problems with the samples
-        AddFile.main(null);
-        
-        CommitAll.main(null);
-        
-        CreateAndDeleteTag.main(null);
-         
-        Log.main(null);    
-    }
-}

JGit/src/test/java/com/baeldung/jgit/porcelain/PorcelainUnitTest.java

@@ -0,0 +1,17 @@
+package com.baeldung.jgit.porcelain;
+
+import org.junit.Test;
+
+public class PorcelainUnitTest {
+    @Test
+    public void runSamples() throws Exception {
+        // simply call all the samples to see any severe problems with the samples
+        AddFile.main(null);
+        
+        CommitAll.main(null);
+        
+        CreateAndDeleteTag.main(null);
+         
+        Log.main(null);    
+    }
+}

Twitter4J/README.md

@@ -0,0 +1,3 @@
+### Relevant articles
+
+- [Introduction to Twitter4J](http://www.baeldung.com/twitter4j)

Twitter4J/pom.xml

@@ -0,0 +1,52 @@
+<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.mabsisa</groupId>
+  <artifactId>Twitter4J</artifactId>
+  <packaging>jar</packaging>
+  <version>1.0-SNAPSHOT</version>
+  <name>Twitter4J</name>
+  <url>http://maven.apache.org</url>
+    
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+     </parent>
+         
+	<properties>
+	    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+	    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+	    <java.version>1.8</java.version>
+	</properties>
+
+    <dependencies>
+		<dependency>
+    		<groupId>org.twitter4j</groupId>
+    		<artifactId>twitter4j-stream</artifactId>
+    		<version>4.0.6</version>
+		</dependency>
+    </dependencies>
+    
+    <build>
+	    <finalName>${project.artifactId}</finalName>
+	    <resources>
+      		<resource>
+			<directory>src/main/resources</directory>
+      		</resource>
+	    </resources>
+	    <plugins>
+      		<plugin>
+        		<groupId>org.apache.maven.plugins</groupId>
+        		<artifactId>maven-surefire-plugin</artifactId>
+        		<version>${maven-surefire-plugin.version}</version>
+        		<configuration>
+          			<excludes>
+            			<exclude>**/ApplicationTest.java</exclude>
+          			</excludes>
+        		</configuration>
+      		</plugin>
+    	</plugins>
+	</build>
+
+</project>

Twitter4J/src/main/java/com/baeldung/Application.java

@@ -0,0 +1,116 @@
+/**
+ * 
+ */
+package com.baeldung;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import twitter4j.DirectMessage;
+import twitter4j.Query;
+import twitter4j.QueryResult;
+import twitter4j.StallWarning;
+import twitter4j.Status;
+import twitter4j.StatusDeletionNotice;
+import twitter4j.StatusListener;
+import twitter4j.Twitter;
+import twitter4j.TwitterException;
+import twitter4j.TwitterFactory;
+import twitter4j.TwitterStream;
+import twitter4j.TwitterStreamFactory;
+import twitter4j.conf.ConfigurationBuilder;
+
+public class Application {
+
+	public static Twitter getTwitterinstance() {
+		/**
+		 * if not using properties file, we can set access token by following way
+		 */
+//		ConfigurationBuilder cb = new ConfigurationBuilder();
+//		cb.setDebugEnabled(true)
+//		  .setOAuthConsumerKey("//TODO")
+//		  .setOAuthConsumerSecret("//TODO")
+//		  .setOAuthAccessToken("//TODO")
+//		  .setOAuthAccessTokenSecret("//TODO");
+//		TwitterFactory tf = new TwitterFactory(cb.build());
+//		Twitter twitter = tf.getSingleton();
+		
+		Twitter twitter = TwitterFactory.getSingleton();
+		return twitter;
+		
+	}
+	
+	public static String createTweet(String tweet) throws TwitterException {
+		Twitter twitter = getTwitterinstance();
+		Status status = twitter.updateStatus("creating baeldung API");
+	        return status.getText();
+	}
+	
+	public static List<String> getTimeLine() throws TwitterException {
+		Twitter twitter = getTwitterinstance();
+		List<Status> statuses = twitter.getHomeTimeline();
+		return statuses.stream().map(
+				item -> item.getText()).collect(
+						Collectors.toList());
+	}
+	
+	public static String sendDirectMessage(String recipientName, String msg) throws TwitterException {
+		Twitter twitter = getTwitterinstance();
+	        DirectMessage message = twitter.sendDirectMessage(recipientName, msg);
+	        return message.getText();
+	}
+	
+	public static List<String> searchtweets() throws TwitterException {
+		Twitter twitter = getTwitterinstance();
+	        Query query = new Query("source:twitter4j baeldung");
+	        QueryResult result = twitter.search(query);
+	        List<Status> statuses = result.getTweets();
+	        return statuses.stream().map(
+				item -> item.getText()).collect(
+						Collectors.toList());
+	}
+	
+	public static void streamFeed() {
+		
+		StatusListener listener = new StatusListener(){
+
+			@Override
+			public void onException(Exception e) {
+				e.printStackTrace();
+			}
+
+			@Override
+			public void onDeletionNotice(StatusDeletionNotice arg) {
+                                System.out.println("Got a status deletion notice id:" + arg.getStatusId());
+			}
+
+			@Override
+			public void onScrubGeo(long userId, long upToStatusId) {
+                                System.out.println("Got scrub_geo event userId:" + userId + " upToStatusId:" + upToStatusId);
+			}
+
+			@Override
+			public void onStallWarning(StallWarning warning) {
+                                System.out.println("Got stall warning:" + warning);
+			}
+
+			@Override
+			public void onStatus(Status status) {
+                                System.out.println(status.getUser().getName() + " : " + status.getText());
+			}
+
+			@Override
+			public void onTrackLimitationNotice(int numberOfLimitedStatuses) {
+                                System.out.println("Got track limitation notice:" + numberOfLimitedStatuses);
+			}
+		};
+	
+		TwitterStream twitterStream = new TwitterStreamFactory().getInstance();
+		
+	        twitterStream.addListener(listener);
+	    
+	        twitterStream.sample();
+		
+	}
+	
+}

Twitter4J/src/main/resources/twitter4j.properties

@@ -0,0 +1,4 @@
+oauth.consumerKey=//TODO
+oauth.consumerSecret=//TODO
+oauth.accessToken=//TODO
+oauth.accessTokenSecret=//TODO

Twitter4J/src/test/java/com/baeldung/ApplicationIntegrationTest.java

@@ -0,0 +1,40 @@
+package com.baeldung;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Test;
+
+import twitter4j.TwitterException;
+
+public class ApplicationIntegrationTest {
+
+	/**
+	 * In order run this jUnit test you need to configure your API details in the twitter4j.properties
+	 */
+	
+	String tweet = "baeldung is awsome";
+	
+	@Test
+	public void givenText_updateStatus() throws TwitterException {
+		String text = Application.createTweet(tweet);
+		assertEquals(tweet, text);
+	}
+	
+	@Test
+	public void givenCredential_fetchStatus() throws TwitterException {
+		List<String> statuses = Application.getTimeLine();
+		List<String> expectedStatuses = new ArrayList<String>();
+		expectedStatuses.add(tweet);
+		assertEquals(expectedStatuses, statuses);
+	}
+	
+	@Test
+	public void givenRecipientNameAndMessage_sendDirectMessage() throws TwitterException {
+		String msg = Application.sendDirectMessage("YOUR_RECCIPIENT_ID", tweet);
+		assertEquals(msg, tweet);
+	}
+	
+}

akka-streams/README.md

@@ -0,0 +1,3 @@
+### Relevant articles
+
+- [Guide to Akka Streams](http://www.baeldung.com/akka-streams)

akka-streams/pom.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>akka-streams</artifactId>
+    <name>akka-streams</name>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.typesafe.akka</groupId>
+            <artifactId>akka-stream_2.11</artifactId>
+            <version>${akkastreams.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.typesafe.akka</groupId>
+            <artifactId>akka-stream-testkit_2.11</artifactId>
+            <version>${akkastreams.version}</version>
+        </dependency>
+    </dependencies>
+    <properties>
+        <akkastreams.version>2.5.2</akkastreams.version>
+    </properties>
+
+</project>

akka-streams/src/main/java/com/baeldung/akkastreams/AverageRepository.java

@@ -0,0 +1,14 @@
+package com.baeldung.akkastreams;
+
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+
+public class AverageRepository {
+    CompletionStage<Double> save(Double average) {
+        return CompletableFuture.supplyAsync(() -> {
+            System.out.println("saving average: " + average);
+            return average;
+        });
+    }
+}

akka-streams/src/main/java/com/baeldung/akkastreams/DataImporter.java

@@ -0,0 +1,74 @@
+package com.baeldung.akkastreams;
+
+
+import akka.Done;
+import akka.NotUsed;
+import akka.actor.ActorSystem;
+import akka.stream.ActorMaterializer;
+import akka.stream.javadsl.Flow;
+import akka.stream.javadsl.Keep;
+import akka.stream.javadsl.Sink;
+import akka.stream.javadsl.Source;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+import java.util.stream.Collectors;
+
+public class DataImporter {
+    private final ActorSystem actorSystem;
+    private final AverageRepository averageRepository = new AverageRepository();
+
+    public DataImporter(ActorSystem actorSystem) {
+        this.actorSystem = actorSystem;
+
+    }
+
+    private List<Integer> parseLine(String line) {
+        String[] fields = line.split(";");
+        return Arrays.stream(fields)
+                .map(Integer::parseInt)
+                .collect(Collectors.toList());
+    }
+
+    private Flow<String, Integer, NotUsed> parseContent() {
+        return Flow.of(String.class).mapConcat(this::parseLine);
+    }
+
+    private Flow<Integer, Double, NotUsed> computeAverage() {
+        return Flow.of(Integer.class).grouped(2).mapAsyncUnordered(8, integers ->
+                CompletableFuture.supplyAsync(() -> integers
+                        .stream()
+                        .mapToDouble(v -> v)
+                        .average()
+                        .orElse(-1.0)));
+    }
+
+    Flow<String, Double, NotUsed> calculateAverage() {
+        return Flow.of(String.class)
+                .via(parseContent())
+                .via(computeAverage());
+    }
+
+    private Sink<Double, CompletionStage<Done>> storeAverages() {
+        return Flow.of(Double.class)
+                .mapAsyncUnordered(4, averageRepository::save)
+                .toMat(Sink.ignore(), Keep.right());
+    }
+
+
+    CompletionStage<Done> calculateAverageForContent(String content) {
+        return Source.single(content)
+                .via(calculateAverage())
+                .runWith(storeAverages(), ActorMaterializer.create(actorSystem))
+                .whenComplete((d, e) -> {
+                    if (d != null) {
+                        System.out.println("Import finished ");
+                    } else {
+                        e.printStackTrace();
+                    }
+                });
+    }
+
+}

akka-streams/src/test/java/com/baeldung/akkastreams/DataImporterUnitTest.java

@@ -0,0 +1,43 @@
+package com.baeldung.akkastreams;
+
+import akka.NotUsed;
+import akka.actor.ActorSystem;
+import akka.stream.ActorMaterializer;
+import akka.stream.javadsl.Flow;
+import akka.stream.javadsl.Source;
+import akka.stream.testkit.javadsl.TestSink;
+import org.junit.Test;
+
+
+public class DataImporterUnitTest {
+    private final ActorSystem actorSystem = ActorSystem.create();
+
+    @Test
+    public void givenStreamOfIntegers_whenCalculateAverageOfPairs_thenShouldReturnProperResults() {
+        //given
+        Flow<String, Double, NotUsed> tested = new DataImporter(actorSystem).calculateAverage();
+        String input = "1;9;11;0";
+
+        //when
+        Source<Double, NotUsed> flow = Source.single(input).via(tested);
+
+        //then
+        flow
+                .runWith(TestSink.probe(actorSystem), ActorMaterializer.create(actorSystem))
+                .request(4)
+                .expectNextUnordered(5d, 5.5);
+    }
+
+    @Test
+    public void givenStreamOfIntegers_whenCalculateAverageAndSaveToSink_thenShouldFinishSuccessfully() {
+        //given
+        DataImporter dataImporter = new DataImporter(actorSystem);
+        String input = "10;90;110;10";
+
+        //when
+        dataImporter.calculateAverageForContent(input)
+                .thenAccept(d -> actorSystem.terminate());
+
+    }
+
+}

algorithms/.gitignore

@@ -0,0 +1 @@
+/target/

algorithms/README.md

@@ -0,0 +1,10 @@
+## Relevant articles:
+
+- [Dijkstra Algorithm in Java](http://www.baeldung.com/java-dijkstra)
+- [Introduction to Cobertura](http://www.baeldung.com/cobertura)
+- [Ant Colony Optimization](http://www.baeldung.com/java-ant-colony-optimization)
+- [Validating Input With Finite Automata in Java](http://www.baeldung.com/finite-automata-java)
+- [Introduction to Jenetics Library](http://www.baeldung.com/jenetics)
+- [Check If a Number Is Prime in Java](http://www.baeldung.com/java-prime-numbers)
+- [Example of Hill Climbing Algorithm](http://www.baeldung.com/java-hill-climbing-algorithm)
+- [Monte Carlo Tree Search for Tic-Tac-Toe Game](http://www.baeldung.com/java-monte-carlo-tree-search)

algorithms/pom.xml

@@ -1,44 +1,69 @@
 <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>algorithms</artifactId>
-	<version>0.0.1-SNAPSHOT</version>
+    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>algorithms</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
 
-	<properties>
-		<junit.version>4.12</junit.version>
-		<maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
-		<exec-maven-plugin.version>1.5.0</exec-maven-plugin.version>
-	</properties>
+    <properties>
+        <exec-maven-plugin.version>1.5.0</exec-maven-plugin.version>
+        <lombok.version>1.16.12</lombok.version>
+        <commons-math3.version>3.6.1</commons-math3.version>
+    </properties>
 
-	<dependencies>
-		<dependency>
-			<groupId>junit</groupId>
-			<artifactId>junit</artifactId>
-			<version>${junit.version}</version>
-			<scope>test</scope>
-		</dependency>
-	</dependencies>
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
 
-	<build>
-		<defaultGoal>install</defaultGoal>
-		<pluginManagement>
-			<plugins>
-				<plugin>
-					<groupId>org.apache.maven.plugins</groupId>
-					<artifactId>maven-compiler-plugin</artifactId>
-					<version>${maven-compiler-plugin.version}</version>
-					<configuration>
-						<source>1.8</source>
-						<target>1.8</target>
-					</configuration>
-				</plugin>
-				<plugin>
-					<groupId>org.codehaus.mojo</groupId>
-					<artifactId>exec-maven-plugin</artifactId>
-					<version>${exec-maven-plugin.version}</version>
-				</plugin>
-			</plugins>
-		</pluginManagement>
-	</build>
-</project>
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.jenetics</groupId>
+            <artifactId>jenetics</artifactId>
+            <version>3.7.0</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>exec-maven-plugin</artifactId>
+                    <version>${exec-maven-plugin.version}</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+    <reporting>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>cobertura-maven-plugin</artifactId>
+                <version>2.7</version>
+                <configuration>
+                    <instrumentation>
+                        <ignores>
+                            <ignore>com/baeldung/algorithms/dijkstra/*</ignore>
+                        </ignores>
+                        <excludes>
+                            <exclude>com/baeldung/algorithms/dijkstra/*</exclude>
+                        </excludes>
+                    </instrumentation>
+                </configuration>
+            </plugin>
+        </plugins>
+    </reporting>
+</project>

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

@@ -0,0 +1,53 @@
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public class BinarySearch {
+
+    public int runBinarySearchIteratively(int[] sortedArray, int key, int low, int high) {
+
+        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;
+    }
+
+    public int runBinarySearchRecursively(int[] sortedArray, int key, int low, int high) {
+
+        int middle = (low + high) / 2;
+        if (high < low) {
+            return -1;
+        }
+
+        if (key == sortedArray[middle]) {
+          return middle;
+        } else if (key < sortedArray[middle]) {
+          return runBinarySearchRecursively(sortedArray, key, low, middle - 1);
+        } else {
+          return runBinarySearchRecursively(sortedArray, key, middle + 1, high);
+        }
+    }
+
+    public int runBinarySearchUsingJavaArrays(int[] sortedArray, Integer key) {
+        int index = Arrays.binarySearch(sortedArray, key);
+        return index;
+    }
+
+    public int runBinarySearchUsingJavaCollections(List<Integer> sortedList, Integer key) {
+        int index = Collections.binarySearch(sortedList, key);
+        return index;
+    }
+
+}

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

@@ -0,0 +1,47 @@
+package com.baeldung.algorithms;
+
+import java.util.Scanner;
+
+import com.baeldung.algorithms.ga.annealing.SimulatedAnnealing;
+import com.baeldung.algorithms.ga.ant_colony.AntColonyOptimization;
+import com.baeldung.algorithms.ga.binary.SimpleGeneticAlgorithm;
+import com.baeldung.algorithms.slope_one.SlopeOne;
+
+public class RunAlgorithm {
+
+	public static void main(String[] args) throws InstantiationException, IllegalAccessException {
+		Scanner in = new Scanner(System.in);
+		System.out.println("Run algorithm:");
+		System.out.println("1 - Simulated Annealing");
+		System.out.println("2 - Slope One");
+		System.out.println("3 - Simple Genetic Algorithm");
+		System.out.println("4 - Ant Colony");
+		System.out.println("5 - Dijkstra");
+		int decision = in.nextInt();
+		switch (decision) {
+		case 1:
+			System.out.println(
+					"Optimized distance for travel: " + SimulatedAnnealing.simulateAnnealing(10, 10000, 0.9995));
+			break;
+		case 2:
+			SlopeOne.slopeOne(3);
+			break;
+		case 3:
+			SimpleGeneticAlgorithm ga = new SimpleGeneticAlgorithm();
+			ga.runAlgorithm(50, "1011000100000100010000100000100111001000000100000100000000001111");
+			break;
+		case 4:
+			AntColonyOptimization antColony = new AntColonyOptimization(21);
+			antColony.startAntOptimization();
+			break;
+		case 5:
+			System.out.println("Please run the DijkstraAlgorithmTest.");
+			break;
+		default:
+			System.out.println("Unknown option");
+			break;
+		}
+		in.close();
+	}
+
+}

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

@@ -0,0 +1,20 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * Finite state machine.
+ */
+public interface FiniteStateMachine {
+
+    /**
+     * Follow a transition, switch the state of the machine.
+     * @param c Char.
+     * @return A new finite state machine with the new state.
+     */
+    FiniteStateMachine switchState(final CharSequence c);
+
+    /**
+     * Is the current state a final one?
+     * @return true or false.
+     */
+    boolean canStop();
+}

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

@@ -0,0 +1,30 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * Default implementation of a finite state machine.
+ * This class is immutable and thread-safe.
+ */
+public final class RtFiniteStateMachine implements FiniteStateMachine {
+
+    /**
+     * Current state.
+     */
+    private State current;
+
+    /**
+     * Ctor.
+     * @param initial Initial state of this machine.
+     */
+    public RtFiniteStateMachine(final State initial) {
+        this.current = initial;
+    }
+
+    public FiniteStateMachine switchState(final CharSequence c) {
+        return new RtFiniteStateMachine(this.current.transit(c));
+    }
+
+    public boolean canStop() {
+        return this.current.isFinal();
+    }
+
+}

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

@@ -0,0 +1,42 @@
+package com.baeldung.algorithms.automata;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * State in a finite state machine.
+ */
+public final class RtState implements State {
+
+    private List<Transition> transitions;
+    private boolean isFinal;
+
+    public RtState() {
+        this(false);
+    }
+    
+    public RtState(final boolean isFinal) {
+        this.transitions = new ArrayList<>();
+        this.isFinal = isFinal;
+    }
+
+    public State transit(final CharSequence c) {
+        return transitions
+          .stream()
+          .filter(t -> t.isPossible(c))
+          .map(Transition::state)
+          .findAny()
+          .orElseThrow(() -> new IllegalArgumentException("Input not accepted: " + c));
+    }
+
+    public boolean isFinal() {
+        return this.isFinal;
+    }
+
+    @Override
+    public State with(Transition tr) {
+        this.transitions.add(tr);
+        return this;
+    }
+
+}

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

@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.automata;
+
+
+/**
+ * Transition in finite state machine.
+ */
+public final class RtTransition implements Transition {
+
+    private String rule;
+    private State next;
+    
+    /**
+     * Ctor.
+     * @param rule Rule that a character has to meet 
+     *  in order to get to the next state.  
+     * @param next Next state.
+     */
+    public RtTransition (String rule, State next) {
+        this.rule = rule;
+        this.next = next;
+    }
+    
+    public State state() {
+        return this.next;
+    }
+
+    public boolean isPossible(CharSequence c) {
+        return this.rule.equalsIgnoreCase(String.valueOf(c));
+    }
+
+}

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

@@ -0,0 +1,29 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * State. Part of a finite state machine.
+ */
+public interface State {
+
+    /**
+     * Add a Transition to this state.
+     * @param tr Given transition.
+     * @return Modified State.
+     */
+    State with(final Transition tr);
+
+    /**
+     * Follow one of the transitions, to get 
+     * to the next state.
+     * @param c Character.
+     * @return State.
+     * @throws IllegalStateException if the char is not accepted.
+     */
+    State transit(final CharSequence c);
+    
+    /**
+     * Can the automaton stop on this state?
+     * @return true or false
+     */
+    boolean isFinal();
+}

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

@@ -0,0 +1,20 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * Transition in a finite State machine.
+ */
+public interface Transition {
+
+    /**
+     * Is the transition possible with the given character?
+     * @param c char.
+     * @return true or false.
+     */
+    boolean isPossible(final CharSequence c);
+
+    /**
+     * The state to which this transition leads.
+     * @return State.
+     */
+    State state();
+}

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

@@ -1,58 +0,0 @@
-package com.baeldung.algorithms.dijkstra;
-
-import java.util.HashMap;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-
-public class Node {
-
-    private String name;
-
-    private LinkedList<Node> shortestPath = new LinkedList<>();
-
-    private Integer distance = Integer.MAX_VALUE;
-
-    private Map<Node, Integer> adjacentNodes = new HashMap<>();
-
-    public Node(String name) {
-        this.name = name;
-    }
-
-    public void addDestination(Node destination, int distance) {
-        adjacentNodes.put(destination, distance);
-    }
-
-    public String getName() {
-        return name;
-    }
-
-    public void setName(String name) {
-        this.name = name;
-    }
-
-    public Map<Node, Integer> getAdjacentNodes() {
-        return adjacentNodes;
-    }
-
-    public void setAdjacentNodes(Map<Node, Integer> adjacentNodes) {
-        this.adjacentNodes = adjacentNodes;
-    }
-
-    public Integer getDistance() {
-        return distance;
-    }
-
-    public void setDistance(Integer distance) {
-        this.distance = distance;
-    }
-
-    public List<Node> getShortestPath() {
-        return shortestPath;
-    }
-
-    public void setShortestPath(LinkedList<Node> shortestPath) {
-        this.shortestPath = shortestPath;
-    }
-
-}