Merge branch 'master' into sla-pr/1272-testng

JGit/README.md

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

algorithms/README.md

@@ -0,0 +1,4 @@
+## Relevant articles:
+
+- [Dijkstra Algorithm in Java](http://www.baeldung.com/java-dijkstra)
+- [Introduction to Cobertura](http://www.baeldung.com/cobertura)

algorithms/pom.xml

@@ -41,4 +41,23 @@
 			</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>

apache-bval/README.md

@@ -0,0 +1,2 @@
+### Relevant Articles:
+- [Intro to Apache BVal](http://www.baeldung.com/apache-bval)

apache-solrj/pom.xml

@@ -0,0 +1,50 @@
+<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-solrj</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <name>apache-solrj</name>
+
+	<properties>
+		<junit.version>4.12</junit.version>
+		<maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.apache.solr</groupId>
+			<artifactId>solr-solrj</artifactId>
+			<version>6.4.0</version>
+		</dependency>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>${junit.version}</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>2.3.2</version>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<version>${maven-surefire-plugin.version}</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+					<excludes>
+						<exclude>**/*IntegrationTest.java</exclude>
+						<exclude>**/*LiveTest.java</exclude>
+					</excludes>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+</project>

apache-solrj/src/main/java/com/baeldung/solrjava/ProductBean.java

@@ -0,0 +1,44 @@
+package com.baeldung.solrjava;
+
+import org.apache.solr.client.solrj.beans.Field;
+
+public class ProductBean {
+
+    String id;
+    String name;
+    String price;
+
+    public ProductBean(String id, String name, String price) {
+        super();
+        this.id = id;
+        this.name = name;
+        this.price = price;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    @Field("id")
+    protected void setId(String id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Field("name")
+    protected void setName(String name) {
+        this.name = name;
+    }
+
+    public String getPrice() {
+        return price;
+    }
+
+    @Field("price")
+    protected void setPrice(String price) {
+        this.price = price;
+    }
+}

apache-solrj/src/main/java/com/baeldung/solrjava/SolrJavaIntegration.java

@@ -0,0 +1,56 @@
+package com.baeldung.solrjava;
+
+import java.io.IOException;
+
+import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.client.solrj.impl.HttpSolrClient;
+import org.apache.solr.client.solrj.impl.XMLResponseParser;
+import org.apache.solr.common.SolrInputDocument;
+
+public class SolrJavaIntegration {
+
+    private HttpSolrClient solrClient;
+
+    public SolrJavaIntegration(String clientUrl) {
+
+        solrClient = new HttpSolrClient.Builder(clientUrl).build();
+        solrClient.setParser(new XMLResponseParser());
+    }
+
+    public void addProductBean(ProductBean pBean) throws IOException, SolrServerException {
+
+        solrClient.addBean(pBean);
+        solrClient.commit();
+    }
+
+    public void addSolrDocument(String documentId, String itemName, String itemPrice) throws SolrServerException, IOException {
+
+        SolrInputDocument document = new SolrInputDocument();
+        document.addField("id", documentId);
+        document.addField("name", itemName);
+        document.addField("price", itemPrice);
+        solrClient.add(document);
+        solrClient.commit();
+    }
+
+    public void deleteSolrDocumentById(String documentId) throws SolrServerException, IOException {
+
+        solrClient.deleteById(documentId);
+        solrClient.commit();
+    }
+
+    public void deleteSolrDocumentByQuery(String query) throws SolrServerException, IOException {
+
+        solrClient.deleteByQuery(query);
+        solrClient.commit();
+    }
+
+    protected HttpSolrClient getSolrClient() {
+        return solrClient;
+    }
+
+    protected void setSolrClient(HttpSolrClient solrClient) {
+        this.solrClient = solrClient;
+    }
+
+}

apache-solrj/src/test/java/com/baeldung/solrjava/SolrJavaIntegrationTest.java

@@ -0,0 +1,108 @@
+package com.baeldung.solrjava;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+
+import org.apache.solr.client.solrj.SolrQuery;
+import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.client.solrj.response.QueryResponse;
+import org.apache.solr.common.SolrDocument;
+import org.apache.solr.common.SolrDocumentList;
+import org.junit.Before;
+import org.junit.Test;
+
+public class SolrJavaIntegrationTest {
+
+    private SolrJavaIntegration solrJavaIntegration;
+
+    @Before
+    public void setUp() throws Exception {
+
+        solrJavaIntegration = new SolrJavaIntegration("http://localhost:8983/solr/bigboxstore");
+        solrJavaIntegration.addSolrDocument("123456", "Kenmore Dishwasher", "599.99");
+    }
+
+    @Test
+    public void whenAdd_thenVerifyAddedByQueryOnId() throws SolrServerException, IOException {
+
+        SolrQuery query = new SolrQuery();
+        query.set("q", "id:123456");
+        QueryResponse response = null;
+
+        response = solrJavaIntegration.getSolrClient().query(query);
+
+        SolrDocumentList docList = response.getResults();
+        assertEquals(docList.getNumFound(), 1);
+
+        for (SolrDocument doc : docList) {
+            assertEquals("Kenmore Dishwasher", (String) doc.getFieldValue("name"));
+            assertEquals((Double) 599.99, (Double) doc.getFieldValue("price"));
+        }
+    }
+
+    @Test
+    public void whenAdd_thenVerifyAddedByQueryOnPrice() throws SolrServerException, IOException {
+
+        SolrQuery query = new SolrQuery();
+        query.set("q", "price:599.99");
+        QueryResponse response = null;
+
+        response = solrJavaIntegration.getSolrClient().query(query);
+
+        SolrDocumentList docList = response.getResults();
+        assertEquals(1, docList.getNumFound());
+
+        for (SolrDocument doc : docList) {
+            assertEquals("123456", (String) doc.getFieldValue("id"));
+            assertEquals((Double) 599.99, (Double) doc.getFieldValue("price"));
+        }
+    }
+
+    @Test
+    public void whenAdd_thenVerifyAddedByQuery() throws SolrServerException, IOException {
+
+        SolrDocument doc = solrJavaIntegration.getSolrClient().getById("123456");
+        assertEquals("Kenmore Dishwasher", (String) doc.getFieldValue("name"));
+        assertEquals((Double) 599.99, (Double) doc.getFieldValue("price"));
+    }
+
+    @Test
+    public void whenAddBean_thenVerifyAddedByQuery() throws SolrServerException, IOException {
+
+        ProductBean pBean = new ProductBean("888", "Apple iPhone 6s", "299.99");
+        solrJavaIntegration.addProductBean(pBean);
+
+        SolrDocument doc = solrJavaIntegration.getSolrClient().getById("888");
+        assertEquals("Apple iPhone 6s", (String) doc.getFieldValue("name"));
+        assertEquals((Double) 299.99, (Double) doc.getFieldValue("price"));
+    }
+
+    @Test
+    public void whenDeleteById_thenVerifyDeleted() throws SolrServerException, IOException {
+
+        solrJavaIntegration.deleteSolrDocumentById("123456");
+
+        SolrQuery query = new SolrQuery();
+        query.set("q", "id:123456");
+        QueryResponse response = solrJavaIntegration.getSolrClient().query(query);
+
+        SolrDocumentList docList = response.getResults();
+        assertEquals(0, docList.getNumFound());
+    }
+
+    @Test
+    public void whenDeleteByQuery_thenVerifyDeleted() throws SolrServerException, IOException {
+
+        solrJavaIntegration.deleteSolrDocumentByQuery("name:Kenmore Dishwasher");
+
+        SolrQuery query = new SolrQuery();
+        query.set("q", "id:123456");
+        QueryResponse response = null;
+
+        response = solrJavaIntegration.getSolrClient().query(query);
+
+        SolrDocumentList docList = response.getResults();
+        assertEquals(0, docList.getNumFound());
+    }
+}

apache-thrift/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Working with Apache Thrift](http://www.baeldung.com/apache-thrift)

apache-velocity/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Introduction to Apache Velocity](http://www.baeldung.com/apache-velocity)

aws/pom.xml

@@ -7,17 +7,36 @@
 	<packaging>jar</packaging>
 	<name>aws</name>
 
+	<properties>
+		<commons-io.version>2.5</commons-io.version>
+		<aws-lambda-java-events.version>1.3.0</aws-lambda-java-events.version>
+		<aws-lambda-java-core.version>1.1.0</aws-lambda-java-core.version>
+		<gson.version>2.8.0</gson.version>
+	</properties>
+
 	<dependencies>
 		<dependency>
 			<groupId>com.amazonaws</groupId>
 			<artifactId>aws-lambda-java-core</artifactId>
-			<version>1.1.0</version>
+			<version>${aws-lambda-java-core.version}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>com.amazonaws</groupId>
+			<artifactId>aws-lambda-java-events</artifactId>
+			<version>${aws-lambda-java-events.version}</version>
 		</dependency>
 
 		<dependency>
 			<groupId>commons-io</groupId>
 			<artifactId>commons-io</artifactId>
-			<version>2.5</version>
+			<version>${commons-io.version}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>com.google.code.gson</groupId>
+			<artifactId>gson</artifactId>
+			<version>${gson.version}</version>
 		</dependency>
 	</dependencies>
 
@@ -26,7 +45,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-shade-plugin</artifactId>
-				<version>2.3</version>
+				<version>3.0.0</version>
 				<configuration>
 					<createDependencyReducedPom>false</createDependencyReducedPom>
 				</configuration>

aws/src/main/java/com/baeldung/lambda/dynamodb/SavePersonHandler.java

@@ -0,0 +1,49 @@
+package com.baeldung.lambda.dynamodb;
+
+import com.amazonaws.regions.Region;
+import com.amazonaws.regions.Regions;
+import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient;
+import com.amazonaws.services.dynamodbv2.document.DynamoDB;
+import com.amazonaws.services.dynamodbv2.document.Item;
+import com.amazonaws.services.dynamodbv2.document.PutItemOutcome;
+import com.amazonaws.services.dynamodbv2.document.spec.PutItemSpec;
+import com.amazonaws.services.dynamodbv2.model.ConditionalCheckFailedException;
+import com.amazonaws.services.lambda.runtime.Context;
+import com.amazonaws.services.lambda.runtime.RequestHandler;
+import com.baeldung.lambda.dynamodb.bean.PersonRequest;
+import com.baeldung.lambda.dynamodb.bean.PersonResponse;
+
+public class SavePersonHandler implements RequestHandler<PersonRequest, PersonResponse> {
+
+    private DynamoDB dynamoDb;
+
+    private String DYNAMODB_TABLE_NAME = "Person";
+    private Regions REGION = Regions.US_WEST_2;
+
+    public PersonResponse handleRequest(PersonRequest personRequest, Context context) {
+        this.initDynamoDbClient();
+
+        persistData(personRequest);
+
+        PersonResponse personResponse = new PersonResponse();
+        personResponse.setMessage("Saved Successfully!!!");
+        return personResponse;
+    }
+
+    private PutItemOutcome persistData(PersonRequest personRequest) throws ConditionalCheckFailedException {
+        return this.dynamoDb.getTable(DYNAMODB_TABLE_NAME)
+          .putItem(
+            new PutItemSpec().withItem(new Item()
+              .withNumber("id", personRequest.getId())
+              .withString("firstName", personRequest.getFirstName())
+              .withString("lastName", personRequest.getLastName())
+              .withNumber("age", personRequest.getAge())
+              .withString("address", personRequest.getAddress())));
+    }
+
+    private void initDynamoDbClient() {
+        AmazonDynamoDBClient client = new AmazonDynamoDBClient();
+        client.setRegion(Region.getRegion(REGION));
+        this.dynamoDb = new DynamoDB(client);
+    }
+}

aws/src/main/java/com/baeldung/lambda/dynamodb/bean/PersonRequest.java

@@ -0,0 +1,67 @@
+package com.baeldung.lambda.dynamodb.bean;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+
+public class PersonRequest {
+    private int id;
+    private String firstName;
+    private String lastName;
+    private int age;
+    private String address;
+
+    public static void main(String[] args) {
+        PersonRequest personRequest = new PersonRequest();
+        personRequest.setId(1);
+        personRequest.setFirstName("John");
+        personRequest.setLastName("Doe");
+        personRequest.setAge(30);
+        personRequest.setAddress("United States");
+        System.out.println(personRequest);
+    }
+
+    public String toString() {
+        final Gson gson = new GsonBuilder().setPrettyPrinting().create();
+        return gson.toJson(this);
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+}

aws/src/main/java/com/baeldung/lambda/dynamodb/bean/PersonResponse.java

@@ -0,0 +1,20 @@
+package com.baeldung.lambda.dynamodb.bean;
+
+import com.google.gson.Gson;
+
+public class PersonResponse {
+    private String message;
+
+    public String toString() {
+        final Gson gson = new Gson();
+        return gson.toJson(this);
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+}

core-java-9/README.md

@@ -6,3 +6,5 @@
 
 ### Relevant Articles:
 - [Java 9 Stream API Improvements](http://www.baeldung.com/java-9-stream-api)
+- [Java 9 Convenience Factory Methods for Collections](http://www.baeldung.com/java-9-collections-factory-methods) 
+- [New Stream Collectors in Java 9](http://www.baeldung.com/java9-stream-collectors)

core-java-9/pom.xml

@@ -21,6 +21,11 @@
             <artifactId>slf4j-api</artifactId>
             <version>${org.slf4j.version}</version>
         </dependency>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>${ch.qos.logback.version}</version>
+        </dependency>
 
         <dependency>
             <groupId>org.hamcrest</groupId>
@@ -76,9 +81,9 @@
     
         <!-- logging -->
         <org.slf4j.version>1.7.21</org.slf4j.version>
-
+        <ch.qos.logback.version>1.2.1</ch.qos.logback.version>
         <!-- maven plugins -->
-        <maven-compiler-plugin.version>3.6-jigsaw-SNAPSHOT</maven-compiler-plugin.version>
+        <maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
         <maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
 
         <!-- testing -->

core-java-9/src/test/java/com/baeldung/java9/process/ProcessAPIEnhancementsTest.java

@@ -0,0 +1,133 @@
+package com.baeldung.java9.process;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Stream;
+
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Created by sanaulla on 2/23/2017.
+ */
+
+public class ProcessAPIEnhancementsTest {
+
+    Logger log = LoggerFactory.getLogger(ProcessAPIEnhancementsTest.class);
+
+    @Test
+    public void givenCurrentProcess_whenInvokeGetInfo_thenSuccess() throws IOException {
+        ProcessHandle processHandle = ProcessHandle.current();
+        ProcessHandle.Info processInfo = processHandle.info();
+        assertNotNull(processHandle.getPid());
+        assertEquals(false, processInfo.arguments()
+          .isPresent());
+        assertEquals(true, processInfo.command()
+          .isPresent());
+        assertTrue(processInfo.command()
+          .get()
+          .contains("java"));
+
+        assertEquals(true, processInfo.startInstant()
+          .isPresent());
+        assertEquals(true, processInfo.totalCpuDuration()
+          .isPresent());
+        assertEquals(true, processInfo.user()
+          .isPresent());
+    }
+
+    @Test
+    public void givenSpawnProcess_whenInvokeGetInfo_thenSuccess() throws IOException {
+
+        String javaCmd = ProcessUtils.getJavaCmd()
+          .getAbsolutePath();
+        ProcessBuilder processBuilder = new ProcessBuilder(javaCmd, "-version");
+        Process process = processBuilder.inheritIO()
+          .start();
+        ProcessHandle processHandle = process.toHandle();
+        ProcessHandle.Info processInfo = processHandle.info();
+        assertNotNull(processHandle.getPid());
+        assertEquals(false, processInfo.arguments()
+          .isPresent());
+        assertEquals(true, processInfo.command()
+          .isPresent());
+        assertTrue(processInfo.command()
+          .get()
+          .contains("java"));
+        assertEquals(true, processInfo.startInstant()
+          .isPresent());
+        assertEquals(true, processInfo.totalCpuDuration()
+          .isPresent());
+        assertEquals(true, processInfo.user()
+          .isPresent());
+    }
+
+    @Test
+    public void givenLiveProcesses_whenInvokeGetInfo_thenSuccess() {
+        Stream<ProcessHandle> liveProcesses = ProcessHandle.allProcesses();
+        liveProcesses.filter(ProcessHandle::isAlive)
+            .forEach(ph -> {
+                assertNotNull(ph.getPid());
+                assertEquals(true, ph.info()
+                  .command()
+                  .isPresent());
+                assertEquals(true, ph.info()
+                  .startInstant()
+                  .isPresent());
+                assertEquals(true, ph.info()
+                  .totalCpuDuration()
+                  .isPresent());
+                assertEquals(true, ph.info()
+                  .user()
+                  .isPresent());
+            });
+    }
+
+    @Test
+    public void givenProcess_whenGetChildProcess_thenSuccess() throws IOException {
+        int childProcessCount = 5;
+        for (int i = 0; i < childProcessCount; i++) {
+            String javaCmd = ProcessUtils.getJavaCmd()
+              .getAbsolutePath();
+            ProcessBuilder processBuilder
+              = new ProcessBuilder(javaCmd, "-version");
+            processBuilder.inheritIO().start();
+        }
+
+        Stream<ProcessHandle> children = ProcessHandle.current()
+          .children();
+        children.filter(ProcessHandle::isAlive)
+          .forEach(ph -> log.info("PID: {}, Cmd: {}", ph.getPid(), ph.info()
+            .command()));
+        Stream<ProcessHandle> descendants = ProcessHandle.current()
+          .descendants();
+        descendants.filter(ProcessHandle::isAlive)
+          .forEach(ph -> log.info("PID: {}, Cmd: {}", ph.getPid(), ph.info()
+            .command()));
+    }
+
+    @Test
+    public void givenProcess_whenAddExitCallback_thenSuccess() throws Exception {
+        String javaCmd = ProcessUtils.getJavaCmd()
+          .getAbsolutePath();
+        ProcessBuilder processBuilder
+          = new ProcessBuilder(javaCmd, "-version");
+        Process process = processBuilder.inheritIO()
+          .start();
+        ProcessHandle processHandle = process.toHandle();
+
+        log.info("PID: {} has started", processHandle.getPid());
+        CompletableFuture<ProcessHandle> onProcessExit = processHandle.onExit();
+        onProcessExit.get();
+        assertEquals(false, processHandle.isAlive());
+        onProcessExit.thenAccept(ph -> {
+            log.info("PID: {} has stopped", ph.getPid());
+        });
+    }
+
+}

core-java/README.md

@@ -58,3 +58,24 @@
 - [Guide to java.util.concurrent.BlockingQueue](http://www.baeldung.com/java-blocking-queue)
 - [Guide to CountDownLatch in Java](http://www.baeldung.com/java-countdown-latch)
 - [How to Design a Genetic Algorithm in Java](http://www.baeldung.com/java-genetic-algorithm)
+- [A Guide to ConcurrentMap](http://www.baeldung.com/java-concurrent-map)
+- [Guide to PriorityBlockingQueue in Java](http://www.baeldung.com/java-priority-blocking-queue)
+- [Guide to Java 8 groupingBy Collector](http://www.baeldung.com/java-groupingby-collector)
+- [Avoiding the ConcurrentModificationException in Java](http://www.baeldung.com/java-concurrentmodificationexception)
+- [Guide to WeakHashMap in Java](http://www.baeldung.com/java-weakhashmap)
+- [Strategy Design Pattern in Java 8](http://www.baeldung.com/java-strategy-pattern)
+- [Java 8 and Infinite Streams](http://www.baeldung.com/java-inifinite-streams)
+- [Custom Thread Pools In Java 8 Parallel Streams](http://www.baeldung.com/java-8-parallel-streams-custom-threadpool)
+- [String Operations with Java Streams](http://www.baeldung.com/java-stream-operations-on-strings)
+- [Spring Security – Cache Control Headers](http://www.baeldung.com/spring-security-cache-control-headers)
+- [Basic Introduction to JMX](http://www.baeldung.com/java-management-extensions)
+- [AWS Lambda With Java](http://www.baeldung.com/java-aws-lambda)
+- [Introduction to Nashorn](http://www.baeldung.com/java-nashorn)
+- [Exceptions in Java 8 Lambda Expressions](http://www.baeldung.com/java-lambda-exceptions)
+- [Guide to the Guava BiMap](http://www.baeldung.com/guava-bimap)
+- [Iterable to Stream in Java](http://www.baeldung.com/java-iterable-to-stream)
+- [Java 8 Stream findFirst() vs. findAny()](http://www.baeldung.com/java-stream-findfirst-vs-findany)
+- [Chained Exceptions in Java](http://www.baeldung.com/java-chained-exceptions)
+- [The Java HashMap Under the Hood](http://www.baeldung.com/java-hashmap)
+- [A Guide to LinkedHashMap in Java](http://www.baeldung.com/java-linked-hashmap)
+- [A Guide to TreeMap in Java](http://www.baeldung.com/java-treemap)

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

@@ -2,7 +2,8 @@ package com.baeldung.algorithms;
 
 import java.util.Scanner;
 
-import com.baeldung.algorithms.annealing.SimulatedAnnealing;
+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;
 
@@ -14,6 +15,7 @@ public class RunAlgorithm {
 		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");
 		int decision = in.nextInt();
 		switch (decision) {
 		case 1:
@@ -27,6 +29,10 @@ public class RunAlgorithm {
 			SimpleGeneticAlgorithm ga = new SimpleGeneticAlgorithm();
 			ga.runAlgorithm(50, "1011000100000100010000100000100111001000000100000100000000001111");
 			break;
+		case 4:
+			AntColonyOptimization antColony = new AntColonyOptimization(21);
+			antColony.startAntOptimization();
+			break;
 		default:
 			System.out.println("Unknown option");
 			break;

core-java/src/main/java/com/baeldung/algorithms/ga/annealing/City.java

@@ -1,4 +1,4 @@
-package com.baeldung.algorithms.annealing;
+package com.baeldung.algorithms.ga.annealing;
 
 import lombok.Data;
 

core-java/src/main/java/com/baeldung/algorithms/ga/annealing/SimulatedAnnealing.java

@@ -1,4 +1,4 @@
-package com.baeldung.algorithms.annealing;
+package com.baeldung.algorithms.ga.annealing;
 
 public class SimulatedAnnealing {
 

core-java/src/main/java/com/baeldung/algorithms/ga/annealing/Travel.java

@@ -1,4 +1,4 @@
-package com.baeldung.algorithms.annealing;
+package com.baeldung.algorithms.ga.annealing;
 
 import java.util.ArrayList;
 import java.util.Collections;

core-java/src/main/java/com/baeldung/algorithms/ga/ant_colony/Ant.java

@@ -0,0 +1,37 @@
+package com.baeldung.algorithms.ga.ant_colony;
+
+public class Ant {
+
+	protected int trailSize;
+	protected int trail[];
+	protected boolean visited[];
+
+	public Ant(int tourSize) {
+		this.trailSize = tourSize;
+		this.trail = new int[tourSize];
+		this.visited = new boolean[tourSize];
+	}
+
+	protected void visitCity(int currentIndex, int city) {
+		trail[currentIndex + 1] = city;
+		visited[city] = true;
+	}
+
+	protected boolean visited(int i) {
+		return visited[i];
+	}
+
+	protected double trailLength(double graph[][]) {
+		double length = graph[trail[trailSize - 1]][trail[0]];
+		for (int i = 0; i < trailSize - 1; i++) {
+			length += graph[trail[i]][trail[i + 1]];
+		}
+		return length;
+	}
+
+	protected void clear() {
+		for (int i = 0; i < trailSize; i++)
+			visited[i] = false;
+	}
+
+}

core-java/src/main/java/com/baeldung/algorithms/ga/ant_colony/AntColonyOptimization.java

@@ -0,0 +1,212 @@
+package com.baeldung.algorithms.ga.ant_colony;
+
+import java.util.Arrays;
+import java.util.Random;
+
+public class AntColonyOptimization {
+
+	private double c = 1.0;
+	private double alpha = 1;
+	private double beta = 5;
+	private double evaporation = 0.5;
+	private double Q = 500;
+	private double antFactor = 0.8;
+	private double randomFactor = 0.01;
+
+	private int maxIterations = 1000;
+
+	public int numberOfCities;
+	public int numberOfAnts;
+	private double graph[][];
+	private double trails[][];
+	private Ant ants[];
+	private Random random = new Random();
+	private double probabilities[];
+
+	private int currentIndex;
+
+	public int[] bestTourOrder;
+	public double bestTourLength;
+
+	public AntColonyOptimization(int noOfCities) {
+		graph = generateRandomMatrix(noOfCities);
+		numberOfCities = graph.length;
+		numberOfAnts = (int) (numberOfCities * antFactor);
+
+		trails = new double[numberOfCities][numberOfCities];
+		probabilities = new double[numberOfCities];
+		ants = new Ant[numberOfAnts];
+		for (int j = 0; j < numberOfAnts; j++) {
+			ants[j] = new Ant(numberOfCities);
+		}
+	}
+
+	/**
+	 * Generate initial solution
+	 * @param n
+	 * @return
+	 */
+	public double[][] generateRandomMatrix(int n) {
+		double[][] randomMatrix = new double[n][n];
+		random.setSeed(System.currentTimeMillis());
+		for (int i = 0; i < n; i++) {
+			for (int j = 0; j < n; j++) {
+				Integer r = random.nextInt(100) + 1;
+				randomMatrix[i][j] = Math.abs(r);
+			}
+		}
+		return randomMatrix;
+	}
+	
+	/**
+	 * Perform ant optimization
+	 * @return
+	 */
+	public int[] startAntOptimization() {
+		int[] finalResult = null;
+		for (int i = 1; i <= 3; i++) {
+			System.out.println("Attempt #" + i);
+			finalResult = solve();
+		}
+		return finalResult;
+	}
+	
+	/**
+	 * Use this method to run the main logic
+	 * @return
+	 */
+	private int[] solve() {
+		setupAnts();
+		clearTrails();
+		int iteration = 0;
+		while (iteration < maxIterations) {
+			moveAnts();
+			updateTrails();
+			updateBest();
+			iteration++;
+		}
+		System.out.println("Best tour length: " + (bestTourLength - numberOfCities));
+		System.out.println("Best tour order: " + Arrays.toString(bestTourOrder));
+		return bestTourOrder.clone();
+	}
+	
+	/**
+	 * Prepare ants for the simulation
+	 */
+	private void setupAnts() {
+		currentIndex = -1;
+		for (int i = 0; i < numberOfAnts; i++) {
+			ants[i].clear();
+			ants[i].visitCity(currentIndex, random.nextInt(numberOfCities));
+		}
+		currentIndex++;
+	}
+	
+	/**
+	 * At each iteration, move ants
+	 */
+	private void moveAnts() {
+		while (currentIndex < numberOfCities - 1) {
+			for (Ant a : ants)
+				a.visitCity(currentIndex, selectNextCity(a));
+			currentIndex++;
+		}
+	}
+	
+	/**
+	 * Select next city for each ant
+	 * @param ant
+	 * @return
+	 */
+	private int selectNextCity(Ant ant) {
+		if (random.nextDouble() < randomFactor) {
+			int t = random.nextInt(numberOfCities - currentIndex);
+			int j = -1;
+			for (int i = 0; i < numberOfCities; i++) {
+				if (!ant.visited(i)) {
+					j++;
+				}
+				if (j == t) {
+					return i;
+				}
+			}
+		}
+		calculateProbabilities(ant);
+		double r = random.nextDouble();
+		double total = 0;
+		for (int i = 0; i < numberOfCities; i++) {
+			total += probabilities[i];
+			if (total >= r) {
+				return i;
+			}
+		}
+
+		throw new RuntimeException("There are no other cities");
+	}
+
+	/**
+	 * Calculate the next city picks probabilites
+	 * @param ant
+	 */
+	private void calculateProbabilities(Ant ant) {
+		int i = ant.trail[currentIndex];
+		double pheromone = 0.0;
+		for (int l = 0; l < numberOfCities; l++) {
+			if (!ant.visited(l)) {
+				pheromone += Math.pow(trails[i][l], alpha) * Math.pow(1.0 / graph[i][l], beta);
+			}
+		}
+		for (int j = 0; j < numberOfCities; j++) {
+			if (ant.visited(j)) {
+				probabilities[j] = 0.0;
+			} else {
+				double numerator = Math.pow(trails[i][j], alpha) * Math.pow(1.0 / graph[i][j], beta);
+				probabilities[j] = numerator / pheromone;
+			}
+		}
+	}
+
+	/**
+	 * Update trails that ants used
+	 */
+	private void updateTrails() {
+		for (int i = 0; i < numberOfCities; i++) {
+			for (int j = 0; j < numberOfCities; j++) {
+				trails[i][j] *= evaporation;
+			}
+		}
+		for (Ant a : ants) {
+			double contribution = Q / a.trailLength(graph);
+			for (int i = 0; i < numberOfCities - 1; i++) {
+				trails[a.trail[i]][a.trail[i + 1]] += contribution;
+			}
+			trails[a.trail[numberOfCities - 1]][a.trail[0]] += contribution;
+		}
+	}
+
+	/**
+	 * Update the best solution
+	 */
+	private void updateBest() {
+		if (bestTourOrder == null) {
+			bestTourOrder = ants[0].trail;
+			bestTourLength = ants[0].trailLength(graph);
+		}
+		for (Ant a : ants) {
+			if (a.trailLength(graph) < bestTourLength) {
+				bestTourLength = a.trailLength(graph);
+				bestTourOrder = a.trail.clone();
+			}
+		}
+	}
+
+	/**
+	 * Clear trails after simulation
+	 */
+	private void clearTrails() {
+		for (int i = 0; i < numberOfCities; i++)
+			for (int j = 0; j < numberOfCities; j++)
+				trails[i][j] = c;
+	}
+
+}

core-java/src/main/java/com/baeldung/concurrent/locks/ReentrantLockWithCondition.java

@@ -0,0 +1,83 @@
+package com.baeldung.concurrent.locks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Stack;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
+import static java.lang.Thread.sleep;
+
+public class ReentrantLockWithCondition {
+
+	static Logger logger = LoggerFactory.getLogger(ReentrantLockWithCondition.class);
+
+	Stack<String> stack = new Stack<>();
+	int CAPACITY = 5;
+
+	ReentrantLock lock = new ReentrantLock();
+	Condition stackEmptyCondition = lock.newCondition();
+	Condition stackFullCondition = lock.newCondition();
+
+	public void pushToStack(String item) throws InterruptedException {
+		try {
+			lock.lock();
+			if (stack.size() == CAPACITY) {
+				logger.info(Thread.currentThread().getName() + " wait on stack full");
+				stackFullCondition.await();
+			}
+			logger.info("Pushing the item " + item);
+			stack.push(item);
+			stackEmptyCondition.signalAll();
+		} finally {
+			lock.unlock();
+		}
+
+	}
+
+	public String popFromStack() throws InterruptedException {
+		try {
+			lock.lock();
+			if (stack.size() == 0) {
+				logger.info(Thread.currentThread().getName() + " wait on stack empty");
+				stackEmptyCondition.await();
+			}
+			return stack.pop();
+		} finally {
+			stackFullCondition.signalAll();
+			lock.unlock();
+		}
+	}
+
+	public static void main(String[] args) {
+		final int threadCount = 2;
+		ReentrantLockWithCondition object = new ReentrantLockWithCondition();
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		service.execute(() -> {
+			for (int i = 0; i < 10; i++) {
+				try {
+					object.pushToStack("Item " + i);
+				} catch (InterruptedException e) {
+					e.printStackTrace();
+				}
+			}
+
+		});
+
+		service.execute(() -> {
+			for (int i = 0; i < 10; i++) {
+				try {
+					logger.info("Item popped " + object.popFromStack());
+				} catch (InterruptedException e) {
+					e.printStackTrace();
+				}
+			}
+
+		});
+
+		service.shutdown();
+	}
+}

core-java/src/main/java/com/baeldung/concurrent/locks/SharedObjectWithLock.java

@@ -0,0 +1,92 @@
+package com.baeldung.concurrent.locks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.ReentrantLock;
+
+import static java.lang.Thread.sleep;
+
+public class SharedObjectWithLock {
+
+	Logger logger = LoggerFactory.getLogger(SharedObjectWithLock.class);
+
+	ReentrantLock lock = new ReentrantLock(true);
+
+	int counter = 0;
+
+	public void perform() {
+
+		lock.lock();
+		logger.info("Thread - " + Thread.currentThread().getName() + " acquired the lock");
+		try {
+			logger.info("Thread - " + Thread.currentThread().getName() + " processing");
+			counter++;
+		} catch (Exception exception) {
+			logger.error(" Interrupted Exception ", exception);
+		} finally {
+			lock.unlock();
+			logger.info("Thread - " + Thread.currentThread().getName() + " released the lock");
+		}
+	}
+
+	public void performTryLock() {
+
+		logger.info("Thread - " + Thread.currentThread().getName() + " attempting to acquire the lock");
+		try {
+			boolean isLockAcquired = lock.tryLock(2, TimeUnit.SECONDS);
+			if (isLockAcquired) {
+				try {
+					logger.info("Thread - " + Thread.currentThread().getName() + " acquired the lock");
+
+					logger.info("Thread - " + Thread.currentThread().getName() + " processing");
+					sleep(1000);
+				} finally {
+					lock.unlock();
+					logger.info("Thread - " + Thread.currentThread().getName() + " released the lock");
+
+				}
+			}
+		} catch (InterruptedException exception) {
+			logger.error(" Interrupted Exception ", exception);
+		}
+		logger.info("Thread - " + Thread.currentThread().getName() + " could not acquire the lock");
+	}
+
+	public ReentrantLock getLock() {
+		return lock;
+	}
+
+	boolean isLocked() {
+		return lock.isLocked();
+	}
+
+	boolean hasQueuedThreads() {
+		return lock.hasQueuedThreads();
+	}
+
+	int getCounter() {
+		return counter;
+	}
+
+	public static void main(String[] args) {
+
+		final int threadCount = 2;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		final SharedObjectWithLock object = new SharedObjectWithLock();
+
+		service.execute(() -> {
+			object.perform();
+		});
+		service.execute(() -> {
+			object.performTryLock();
+		});
+
+		service.shutdown();
+
+	}
+
+}

core-java/src/main/java/com/baeldung/concurrent/locks/StampedLockDemo.java

@@ -0,0 +1,104 @@
+package com.baeldung.concurrent.locks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.StampedLock;
+
+import static java.lang.Thread.sleep;
+
+public class StampedLockDemo {
+	Map<String, String> map = new HashMap<>();
+	Logger logger = LoggerFactory.getLogger(StampedLockDemo.class);
+
+	private final StampedLock lock = new StampedLock();
+
+	public void put(String key, String value) throws InterruptedException {
+		long stamp = lock.writeLock();
+
+		try {
+			logger.info(Thread.currentThread().getName() + " acquired the write lock with stamp " + stamp);
+			map.put(key, value);
+		} finally {
+			lock.unlockWrite(stamp);
+			logger.info(Thread.currentThread().getName() + " unlocked the write lock with stamp " + stamp);
+		}
+	}
+
+	public String get(String key) throws InterruptedException {
+		long stamp = lock.readLock();
+		logger.info(Thread.currentThread().getName() + " acquired the read lock with stamp " + stamp);
+		try {
+			sleep(5000);
+			return map.get(key);
+
+		} finally {
+			lock.unlockRead(stamp);
+			logger.info(Thread.currentThread().getName() + " unlocked the read lock with stamp " + stamp);
+
+		}
+
+	}
+
+	public String readWithOptimisticLock(String key) throws InterruptedException {
+		long stamp = lock.tryOptimisticRead();
+		String value = map.get(key);
+
+		if (!lock.validate(stamp)) {
+			stamp = lock.readLock();
+			try {
+				sleep(5000);
+				return map.get(key);
+
+			} finally {
+				lock.unlock(stamp);
+				logger.info(Thread.currentThread().getName() + " unlocked the read lock with stamp " + stamp);
+
+			}
+		}
+		return value;
+	}
+
+	public static void main(String[] args) {
+		final int threadCount = 4;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		StampedLockDemo object = new StampedLockDemo();
+
+		Runnable writeTask = () -> {
+
+			try {
+				object.put("key1", "value1");
+			} catch (InterruptedException e) {
+				e.printStackTrace();
+			}
+		};
+		Runnable readTask = () -> {
+
+			try {
+				object.get("key1");
+			} catch (InterruptedException e) {
+				e.printStackTrace();
+			}
+		};
+		Runnable readOptimisticTask = () -> {
+
+			try {
+				object.readWithOptimisticLock("key1");
+			} catch (InterruptedException e) {
+				e.printStackTrace();
+			}
+		};
+		service.submit(writeTask);
+		service.submit(writeTask);
+		service.submit(readTask);
+		service.submit(readOptimisticTask);
+
+		service.shutdown();
+
+	}
+
+}

core-java/src/main/java/com/baeldung/concurrent/locks/SynchronizedHashMapWithRWLock.java

@@ -0,0 +1,120 @@
+package com.baeldung.concurrent.locks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import static java.lang.Thread.sleep;
+
+public class SynchronizedHashMapWithRWLock {
+
+	static Map<String, String> syncHashMap = new HashMap<>();
+	Logger logger = LoggerFactory.getLogger(SynchronizedHashMapWithRWLock.class);
+
+	private final ReadWriteLock lock = new ReentrantReadWriteLock();
+	private final Lock readLock = lock.readLock();
+	private final Lock writeLock = lock.writeLock();
+
+	public void put(String key, String value) throws InterruptedException {
+
+		try {
+			writeLock.lock();
+			logger.info(Thread.currentThread().getName() + " writing");
+			syncHashMap.put(key, value);
+			sleep(1000);
+		} finally {
+			writeLock.unlock();
+		}
+
+	}
+
+	public String get(String key) {
+		try {
+			readLock.lock();
+			logger.info(Thread.currentThread().getName() + " reading");
+			return syncHashMap.get(key);
+		} finally {
+			readLock.unlock();
+		}
+	}
+
+	public String remove(String key) {
+		try {
+			writeLock.lock();
+			return syncHashMap.remove(key);
+		} finally {
+			writeLock.unlock();
+		}
+	}
+
+	public boolean containsKey(String key) {
+		try {
+			readLock.lock();
+			return syncHashMap.containsKey(key);
+		} finally {
+			readLock.unlock();
+		}
+	}
+
+	boolean isReadLockAvailable() {
+		return readLock.tryLock();
+	}
+
+	public static void main(String[] args) throws InterruptedException {
+
+		final int threadCount = 3;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		SynchronizedHashMapWithRWLock object = new SynchronizedHashMapWithRWLock();
+
+		service.execute(new Thread(new Writer(object), "Writer"));
+		service.execute(new Thread(new Reader(object), "Reader1"));
+		service.execute(new Thread(new Reader(object), "Reader2"));
+
+		service.shutdown();
+	}
+
+	private static class Reader implements Runnable {
+
+		SynchronizedHashMapWithRWLock object;
+
+		public Reader(SynchronizedHashMapWithRWLock object) {
+			this.object = object;
+		}
+
+		@Override
+		public void run() {
+			for (int i = 0; i < 10; i++) {
+				object.get("key" + i);
+			}
+		}
+	}
+
+	private static class Writer implements Runnable {
+
+		SynchronizedHashMapWithRWLock object;
+
+		public Writer(SynchronizedHashMapWithRWLock object) {
+			this.object = object;
+		}
+
+		@Override
+		public void run() {
+			for (int i = 0; i < 10; i++) {
+				try {
+					object.put("key" + i, "value" + i);
+					sleep(1000);
+				} catch (InterruptedException e) {
+					e.printStackTrace();
+				}
+			}
+		}
+	}
+
+}

core-java/src/main/java/com/baeldung/list/listoflist/Pen.java

@@ -0,0 +1,18 @@
+package com.baeldung.list.listoflist;
+
+public class Pen implements Stationery {
+
+    public String name;
+
+    public Pen(String name) {
+        this.name = name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return this.name;
+    }
+}

core-java/src/main/java/com/baeldung/list/listoflist/Pencil.java

@@ -0,0 +1,18 @@
+package com.baeldung.list.listoflist;
+
+public class Pencil implements Stationery{
+    
+    public String name;
+    
+    public Pencil(String name) {
+        this.name = name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return this.name;
+    }
+}

core-java/src/main/java/com/baeldung/list/listoflist/Rubber.java

@@ -0,0 +1,18 @@
+package com.baeldung.list.listoflist;
+
+public class Rubber implements Stationery {
+
+    public String name;
+
+    public Rubber(String name) {
+        this.name = name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return this.name;
+    }
+}

core-java/src/main/java/com/baeldung/list/listoflist/Stationery.java

@@ -0,0 +1,5 @@
+package com.baeldung.list.listoflist;
+
+public interface Stationery {
+
+}

core-java/src/test/java/com/baeldung/algorithms/AntColonyOptimizationTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.algorithms;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.baeldung.algorithms.ga.ant_colony.AntColonyOptimization;
+
+public class AntColonyOptimizationTest {
+
+	@Test
+	public void testGenerateRandomMatrix() {
+		AntColonyOptimization antTSP = new AntColonyOptimization(5);
+		Assert.assertNotNull(antTSP.generateRandomMatrix(5));
+	}
+
+	@Test
+	public void testStartAntOptimization() {
+		AntColonyOptimization antTSP = new AntColonyOptimization(5);
+		Assert.assertNotNull(antTSP.startAntOptimization());
+	}
+
+}

core-java/src/test/java/com/baeldung/algorithms/SimulatedAnnealingTest.java

@@ -3,7 +3,7 @@ package com.baeldung.algorithms;
 import org.junit.Assert;
 import org.junit.Test;
 
-import com.baeldung.algorithms.annealing.SimulatedAnnealing;
+import com.baeldung.algorithms.ga.annealing.SimulatedAnnealing;
 
 public class SimulatedAnnealingTest {
 

core-java/src/test/java/com/baeldung/concurrent/locks/SharedObjectWithLockManualTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.concurrent.locks;
+
+import org.junit.Test;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import static junit.framework.TestCase.assertEquals;
+
+public class SharedObjectWithLockManualTest {
+
+	@Test
+	public void whenLockAcquired_ThenLockedIsTrue() {
+		final SharedObjectWithLock object = new SharedObjectWithLock();
+
+		final int threadCount = 2;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+
+		executeThreads(object, threadCount, service);
+
+		assertEquals(true, object.isLocked());
+
+		service.shutdown();
+	}
+
+	@Test
+	public void whenLocked_ThenQueuedThread() {
+		final int threadCount = 4;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		final SharedObjectWithLock object = new SharedObjectWithLock();
+
+		executeThreads(object, threadCount, service);
+
+		assertEquals(object.hasQueuedThreads(), true);
+
+		service.shutdown();
+
+	}
+
+	public void whenTryLock_ThenQueuedThread() {
+		final SharedObjectWithLock object = new SharedObjectWithLock();
+
+		final int threadCount = 2;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+
+		executeThreads(object, threadCount, service);
+
+		assertEquals(true, object.isLocked());
+
+		service.shutdown();
+	}
+
+	@Test
+	public void whenGetCount_ThenCorrectCount() throws InterruptedException {
+		final int threadCount = 4;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+		final SharedObjectWithLock object = new SharedObjectWithLock();
+
+		executeThreads(object, threadCount, service);
+		Thread.sleep(1000);
+		assertEquals(object.getCounter(), 4);
+
+		service.shutdown();
+
+	}
+
+	private void executeThreads(SharedObjectWithLock object, int threadCount, ExecutorService service) {
+		for (int i = 0; i < threadCount; i++) {
+			service.execute(() -> {
+				object.perform();
+			});
+		}
+	}
+
+}

core-java/src/test/java/com/baeldung/concurrent/locks/SynchronizedHashMapWithRWLockManualTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.concurrent.locks;
+
+import jdk.nashorn.internal.ir.annotations.Ignore;
+import org.junit.Test;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import static junit.framework.TestCase.assertEquals;
+
+public class SynchronizedHashMapWithRWLockManualTest {
+
+	@Test
+	public void whenWriting_ThenNoReading() {
+		SynchronizedHashMapWithRWLock object = new SynchronizedHashMapWithRWLock();
+		final int threadCount = 3;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+
+		executeWriterThreads(object, threadCount, service);
+
+		assertEquals(object.isReadLockAvailable(), false);
+
+		service.shutdown();
+	}
+
+	@Test
+	public void whenReading_ThenMultipleReadingAllowed() {
+		SynchronizedHashMapWithRWLock object = new SynchronizedHashMapWithRWLock();
+		final int threadCount = 5;
+		final ExecutorService service = Executors.newFixedThreadPool(threadCount);
+
+		executeReaderThreads(object, threadCount, service);
+
+		assertEquals(object.isReadLockAvailable(), true);
+
+		service.shutdown();
+	}
+
+	private void executeWriterThreads(SynchronizedHashMapWithRWLock object, int threadCount, ExecutorService service) {
+		for (int i = 0; i < threadCount; i++) {
+			service.execute(() -> {
+				try {
+					object.put("key" + threadCount, "value" + threadCount);
+				} catch (InterruptedException e) {
+					e.printStackTrace();
+				}
+			});
+		}
+	}
+
+	private void executeReaderThreads(SynchronizedHashMapWithRWLock object, int threadCount, ExecutorService service) {
+		for (int i = 0; i < threadCount; i++)
+			service.execute(() -> {
+				object.get("key" + threadCount);
+			});
+	}
+
+}

core-java/src/test/java/com/baeldung/java/map/README.md

@@ -1,2 +0,0 @@
-### Relevant Articles:
-- [The Java HashMap Under the Hood](http://www.baeldung.com/java-hashmap)

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

@@ -0,0 +1,76 @@
+package com.baeldung.list.listoflist;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Before;
+import org.junit.Test;
+
+public class ListOfListsTest {
+
+    private List<ArrayList<? extends Stationery>> listOfLists = new ArrayList<ArrayList<? extends Stationery>>();
+    private ArrayList<Pen> penList = new ArrayList<>();
+    private ArrayList<Pencil> pencilList = new ArrayList<>();
+    private ArrayList<Rubber> rubberList = new ArrayList<>();
+
+    @SuppressWarnings("unchecked")
+    @Before
+    public void init() {
+        listOfLists.add(penList);
+        listOfLists.add(pencilList);
+        listOfLists.add(rubberList);
+
+        ((ArrayList<Pen>) listOfLists.get(0)).add(new Pen("Pen 1"));
+        ((ArrayList<Pencil>) listOfLists.get(1)).add(new Pencil("Pencil 1"));
+        ((ArrayList<Rubber>) listOfLists.get(2)).add(new Rubber("Rubber 1"));
+    }
+
+    @Test
+    public void givenListOfLists_thenCheckNames() {
+        assertEquals("Pen 1", ((Pen) listOfLists.get(0)
+            .get(0)).getName());
+        assertEquals("Pencil 1", ((Pencil) listOfLists.get(1)
+            .get(0)).getName());
+        assertEquals("Rubber 1", ((Rubber) listOfLists.get(2)
+            .get(0)).getName());
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void givenListOfLists_whenRemovingElements_thenCheckNames() {
+
+        ((ArrayList<Pencil>) listOfLists.get(1)).remove(0);
+        listOfLists.remove(1);
+        assertEquals("Rubber 1", ((Rubber) listOfLists.get(1)
+            .get(0)).getName());
+        listOfLists.remove(0);
+        assertEquals("Rubber 1", ((Rubber) listOfLists.get(0)
+            .get(0)).getName());
+    }
+
+    @Test
+    public void givenThreeList_whenCombineIntoOneList_thenCheckList() {
+        ArrayList<Pen> pens = new ArrayList<>();
+        pens.add(new Pen("Pen 1"));
+        pens.add(new Pen("Pen 2"));
+        ArrayList<Pencil> pencils = new ArrayList<>();
+        pencils.add(new Pencil("Pencil 1"));
+        pencils.add(new Pencil("Pencil 2"));
+        ArrayList<Rubber> rubbers = new ArrayList<>();
+        rubbers.add(new Rubber("Rubber 1"));
+        rubbers.add(new Rubber("Rubber 2"));
+        
+        List<ArrayList<? extends Stationery>> list = new ArrayList<ArrayList<? extends Stationery>>();
+        list.add(pens);
+        list.add(pencils);
+        list.add(rubbers);
+        
+        assertEquals("Pen 1", ((Pen) list.get(0)
+            .get(0)).getName());
+        assertEquals("Pencil 1", ((Pencil) list.get(1)
+            .get(0)).getName());
+        assertEquals("Rubber 1", ((Rubber) list.get(2)
+            .get(0)).getName());
+    }
+}

couchbase-sdk/README.md

@@ -4,6 +4,7 @@
 - [Introduction to Couchbase SDK for Java](http://www.baeldung.com/java-couchbase-sdk)
 - [Using Couchbase in a Spring Application](http://www.baeldung.com/couchbase-sdk-spring)
 - [Asynchronous Batch Opereations in Couchbase](http://www.baeldung.com/async-batch-operations-in-couchbase)
+- [Querying Couchbase with MapReduce Views](http://www.baeldung.com/couchbase-query-mapreduce-view)
 
 ### Overview
 This Maven project contains the Java code for the Couchbase entities and Spring services

disruptor/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Concurrency with LMAX Disruptor – An Introduction](http://www.baeldung.com/lmax-disruptor-concurrency)

ejb/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Guide to EJB Set-up](http://www.baeldung.com/ejb-intro)

guava/README.md

@@ -16,3 +16,11 @@
 - [Guava – Sets](http://www.baeldung.com/guava-sets)
 - [Guava – Maps](http://www.baeldung.com/guava-maps)
 - [Guava Set + Function = Map](http://www.baeldung.com/guava-set-function-map-tutorial)
+- [Guide to Guava’s Ordering](http://www.baeldung.com/guava-ordering)
+- [Guide to Guava’s PreConditions](http://www.baeldung.com/guava-preconditions)
+- [Introduction to Guava CacheLoader](http://www.baeldung.com/guava-cacheloader)
+- [Guide to Guava’s EventBus](http://www.baeldung.com/guava-eventbus)
+- [Guide to Guava Multimap](http://www.baeldung.com/guava-multimap)
+- [Guide to Guava RangeSet](http://www.baeldung.com/guava-rangeset)
+- [Guide to Guava RangeMap](http://www.baeldung.com/guava-rangemap)
+- [Guide to Guava Table](http://www.baeldung.com/guava-table)

httpclient/README.md

@@ -19,3 +19,4 @@ The "REST With Spring" Classes: http://bit.ly/restwithspring
 - [Multipart Upload with HttpClient 4](http://www.baeldung.com/httpclient-multipart-upload)
 - [HttpAsyncClient Tutorial](http://www.baeldung.com/httpasyncclient-tutorial)
 - [HttpClient 4 Tutorial](http://www.baeldung.com/httpclient-guide)
+- [Advanced HttpClient Configuration](http://www.baeldung.com/httpclient-advanced-config)

jackson/README.md

@@ -25,3 +25,4 @@ The "REST With Spring" Classes: http://bit.ly/restwithspring
 - [More Jackson Annotations](http://www.baeldung.com/jackson-advanced-annotations)
 - [Inheritance with Jackson](http://www.baeldung.com/jackson-inheritance)
 - [Guide to @JsonFormat in Jackson](http://www.baeldung.com/jackson-jsonformat)
+- [A Guide to Optional with Jackson](http://www.baeldung.com/jackson-optional)

java-mongodb/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [A Guide to MongoDB with Java](http://www.baeldung.com/java-mongodb)

javaslang/README.md

@@ -1,2 +1,4 @@
 ### Relevant Articles:
 - [Introduction to Javaslang](http://www.baeldung.com/javaslang)
+- [Guide to Try in Javaslang](http://www.baeldung.com/javaslang-try)
+- [Guide to Pattern Matching in Javaslang](http://www.baeldung.com/javaslang-pattern-matching)

jee7/README.md

@@ -1,2 +1,3 @@
 ### Relevant Articles:
 - [Scheduling in Java EE](http://www.baeldung.com/scheduling-in-java-enterprise-edition)
+- [JSON Processing in Java EE 7](http://www.baeldung.com/jee7-json)

jee7/src/main/java/com/baeldung/javaeeannotations/AccountServlet.java

@@ -0,0 +1,57 @@
+package com.baeldung.javaeeannotations;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.HttpConstraint;
+import javax.servlet.annotation.HttpMethodConstraint;
+import javax.servlet.annotation.ServletSecurity;
+import javax.servlet.annotation.WebInitParam;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@WebServlet(
+  name = "BankAccountServlet", 
+  description = "Represents a Bank Account and it's transactions", 
+  urlPatterns = {"/account", "/bankAccount" }, 
+  initParams = { @WebInitParam(name = "type", value = "savings") }
+  )
+@ServletSecurity(
+  value = @HttpConstraint(rolesAllowed = {"admin"}),
+  httpMethodConstraints = {@HttpMethodConstraint(value = "POST", rolesAllowed = {"admin"})}
+  )
+public class AccountServlet extends javax.servlet.http.HttpServlet {
+
+    String accountType = null;
+
+    @Override
+    public void init(ServletConfig config) throws ServletException {
+        accountType = config.getInitParameter("type");
+    }
+
+    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
+        PrintWriter writer = response.getWriter();
+        writer.println("<html>Hello, I am an AccountServlet!</html>");
+        writer.flush();
+    }
+
+    public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
+        double accountBalance = 1000d;
+        double interestRate = Double.parseDouble(request.getAttribute("interest").toString());
+
+        String paramDepositAmt = request.getParameter("dep");
+        double depositAmt = Double.parseDouble(paramDepositAmt);
+
+        accountBalance = accountBalance + depositAmt;
+
+        PrintWriter writer = response.getWriter();
+        writer.println("<html> Balance of " + accountType + " account is: " + 
+           accountBalance + "<br> This account bares an interest rate of " + interestRate + 
+           " % </html>");
+        writer.flush();
+
+    }
+}

jee7/src/main/java/com/baeldung/javaeeannotations/BankAppServletContextListener.java

@@ -0,0 +1,17 @@
+package com.baeldung.javaeeannotations;
+
+import javax.servlet.ServletContextEvent;
+import javax.servlet.ServletContextListener;
+import javax.servlet.annotation.WebListener;
+
+@WebListener
+public class BankAppServletContextListener implements ServletContextListener {
+
+    public void contextInitialized(ServletContextEvent sce) { 
+        sce.getServletContext().setAttribute("ATTR_DEFAULT_LANGUAGE", "english"); 
+    } 
+    
+    public void contextDestroyed(ServletContextEvent sce) { 
+        System.out.println("CONTEXT DESTROYED"); 
+    } 
+}

jee7/src/main/java/com/baeldung/javaeeannotations/LoggingFilter.java

@@ -0,0 +1,36 @@
+package com.baeldung.javaeeannotations;
+
+import java.io.IOException;
+
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.annotation.WebFilter;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@WebFilter(
+  urlPatterns = "/bankAccount/*",
+  filterName = "LoggingFilter",
+  description = "Filter all account transaction URLs"
+  )
+public class LoggingFilter implements javax.servlet.Filter {
+    @Override
+    public void init(FilterConfig filterConfig) throws ServletException {
+    }
+
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+        HttpServletRequest req = (HttpServletRequest) request;
+        HttpServletResponse res = (HttpServletResponse) response;
+
+        res.sendRedirect(req.getContextPath() + "/login.jsp");
+        chain.doFilter(request, response);
+    }
+
+    @Override
+    public void destroy() {
+    }
+
+}

jee7/src/main/java/com/baeldung/javaeeannotations/UploadCustomerDocumentsServlet.java

@@ -0,0 +1,29 @@
+package com.baeldung.javaeeannotations;
+
+import java.io.IOException;
+
+import javax.servlet.ServletException;
+import javax.servlet.annotation.MultipartConfig;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.Part;
+
+@WebServlet(urlPatterns = { "/uploadCustDocs" })
+@MultipartConfig(
+  fileSizeThreshold = 1024 * 1024 * 20,
+  maxFileSize = 1024 * 1024 * 20,
+  maxRequestSize = 1024 * 1024 * 25,
+  location = "D:/custDocs"
+  )
+public class UploadCustomerDocumentsServlet extends HttpServlet {
+
+    protected void doPost(
+     HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        for (Part part : request.getParts()) {
+            part.write("myFile");
+        }
+    }
+
+}

jee7/src/main/webapp/WEB-INF/web.xml

@@ -0,0 +1,11 @@
+<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
+                             http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1">
+
+    <login-config>
+        <auth-method>BASIC</auth-method>
+        <realm-name>default</realm-name>
+    </login-config>
+
+</web-app>

jee7/src/main/webapp/index.jsp

@@ -0,0 +1,16 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+    pageEncoding="ISO-8859-1"%>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>My Account</title>
+</head>
+<body>
+<form action="account" method="post">
+        Width: <input type="text" size="5" name="dep"/> 
+        &nbsp;&nbsp;
+        <input type="submit" value="Deposit" />
+</form>
+</body>
+</html>

jee7/src/main/webapp/login.jsp

@@ -0,0 +1,12 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+    pageEncoding="ISO-8859-1"%>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Login</title>
+</head>
+<body>
+Login Here...
+</body>
+</html>

jee7/src/main/webapp/upload.jsp

@@ -0,0 +1,16 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+    pageEncoding="ISO-8859-1"%>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Insert title here</title>
+</head>
+<body>
+<form action="uploadCustDocs" method="post" enctype="multipart/form-data">
+<input type="file" name="file" size="50" />
+<br />
+<input type="submit" value="Upload File" />
+</form>
+</body>
+</html>

jooq/pom.xml

@@ -0,0 +1,46 @@
+<?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>jooq</artifactId>
+    <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>org.jooq</groupId>
+            <artifactId>jool</artifactId>
+            <version>${jool.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <jool.version>0.9.12</jool.version>
+        <junit.version>4.12</junit.version>
+    </properties>
+
+
+</project>

jooq/src/test/java/com/baeldung/JOOLTest.java

@@ -0,0 +1,243 @@
+package com.baeldung;
+
+
+import junit.framework.Assert;
+import org.jooq.lambda.Seq;
+import org.jooq.lambda.Unchecked;
+import org.jooq.lambda.function.Function1;
+import org.jooq.lambda.function.Function2;
+import org.jooq.lambda.tuple.Tuple;
+import org.jooq.lambda.tuple.Tuple2;
+import org.jooq.lambda.tuple.Tuple3;
+import org.jooq.lambda.tuple.Tuple4;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static junit.framework.Assert.assertTrue;
+import static junit.framework.TestCase.assertEquals;
+import static org.jooq.lambda.tuple.Tuple.tuple;
+
+public class JOOLTest {
+    @Test
+    public void givenSeq_whenCheckContains_shouldReturnTrue() {
+        List<Integer> concat = Seq.of(1, 2, 3).concat(Seq.of(4, 5, 6)).toList();
+
+        assertEquals(concat, Arrays.asList(1, 2, 3, 4, 5, 6));
+
+
+        assertTrue(Seq.of(1, 2, 3, 4).contains(2));
+
+
+        assertTrue(Seq.of(1, 2, 3, 4).containsAll(2, 3));
+
+
+        assertTrue(Seq.of(1, 2, 3, 4).containsAny(2, 5));
+    }
+
+    @Test
+    public void givenStreams_whenJoin_shouldHaveElementsFromTwoStreams() {
+        //given
+        Stream<Integer> left = Stream.of(1, 2, 4);
+        Stream<Integer> right = Stream.of(1, 2, 3);
+
+        //when
+        List<Integer> rightCollected = right.collect(Collectors.toList());
+        List<Integer> collect = left.filter(rightCollected::contains).collect(Collectors.toList());
+
+        //then
+        assertEquals(collect, Arrays.asList(1, 2));
+    }
+
+    @Test
+    public void givenSeq_whenJoin_shouldHaveElementsFromBothSeq() {
+        assertEquals(
+                Seq.of(1, 2, 4).innerJoin(Seq.of(1, 2, 3), (a, b) -> a == b).toList(),
+                Arrays.asList(tuple(1, 1), tuple(2, 2))
+        );
+
+
+        assertEquals(
+                Seq.of(1, 2, 4).leftOuterJoin(Seq.of(1, 2, 3), (a, b) -> a == b).toList(),
+                Arrays.asList(tuple(1, 1), tuple(2, 2), tuple(4, null))
+        );
+
+        assertEquals(
+                Seq.of(1, 2, 4).rightOuterJoin(Seq.of(1, 2, 3), (a, b) -> a == b).toList(),
+                Arrays.asList(tuple(1, 1), tuple(2, 2), tuple(null, 3))
+        );
+
+        assertEquals(
+                Seq.of(1, 2).crossJoin(Seq.of("A", "B")).toList(),
+                Arrays.asList(tuple(1, "A"), tuple(1, "B"), tuple(2, "A"), tuple(2, "B"))
+        );
+    }
+
+    @Test
+    public void givenSeq_whenManipulateSeq_seqShouldHaveNewElementsInIt() {
+        assertEquals(
+                Seq.of(1, 2, 3).cycle().limit(9).toList(),
+                Arrays.asList(1, 2, 3, 1, 2, 3, 1, 2, 3)
+        );
+
+        assertEquals(
+                Seq.of(1, 2, 3).duplicate().map((first, second) -> tuple(first.toList(), second.toList())),
+                tuple(Arrays.asList(1, 2, 3), Arrays.asList(1, 2, 3))
+        );
+
+        assertEquals(
+                Seq.of(1, 2, 3, 4).intersperse(0).toList(),
+                Arrays.asList(1, 0, 2, 0, 3, 0, 4)
+        );
+
+        assertEquals(
+                Seq.of(1, 2, 3, 4, 5).shuffle().toList().size(),
+                5
+        );
+
+        assertEquals(
+                Seq.of(1, 2, 3, 4).partition(i -> i > 2).map((first, second) -> tuple(first.toList(), second.toList())),
+                tuple(Arrays.asList(3, 4), Arrays.asList(1, 2))
+
+        );
+
+        assertEquals(
+                Seq.of(1, 2, 3, 4).reverse().toList(),
+                Arrays.asList(4, 3, 2, 1)
+        );
+    }
+
+    @Test
+    public void givenSeq_whenGroupByAndFold_shouldReturnProperSeq() {
+
+        Map<Integer, List<Integer>> expectedAfterGroupBy = new HashMap<>();
+        expectedAfterGroupBy.put(1, Arrays.asList(1, 3));
+        expectedAfterGroupBy.put(0, Arrays.asList(2, 4));
+
+        assertEquals(
+                Seq.of(1, 2, 3, 4).groupBy(i -> i % 2),
+                expectedAfterGroupBy
+        );
+
+
+        assertEquals(
+                Seq.of("a", "b", "c").foldLeft("!", (u, t) -> u + t),
+                "!abc"
+        );
+
+
+        assertEquals(
+                Seq.of("a", "b", "c").foldRight("!", (t, u) -> t + u),
+                "abc!"
+        );
+    }
+
+    @Test
+    public void givenSeq_whenUsingSeqWhile_shouldBehaveAsWhileLoop() {
+
+        assertEquals(
+                Seq.of(1, 2, 3, 4, 5).skipWhile(i -> i < 3).toList(),
+                Arrays.asList(3, 4, 5)
+        );
+
+        assertEquals(
+                Seq.of(1, 2, 3, 4, 5).skipUntil(i -> i == 3).toList(),
+                Arrays.asList(3, 4, 5)
+        );
+    }
+
+    @Test
+    public void givenSeq_whenZip_shouldHaveZippedSeq() {
+
+        assertEquals(
+                Seq.of(1, 2, 3).zip(Seq.of("a", "b", "c")).toList(),
+                Arrays.asList(tuple(1, "a"), tuple(2, "b"), tuple(3, "c"))
+        );
+
+        assertEquals(
+                Seq.of(1, 2, 3).zip(Seq.of("a", "b", "c"), (x, y) -> x + ":" + y).toList(),
+                Arrays.asList("1:a", "2:b", "3:c")
+        );
+
+
+        assertEquals(
+                Seq.of("a", "b", "c").zipWithIndex().toList(),
+                Arrays.asList(tuple("a", 0L), tuple("b", 1L), tuple("c", 2L))
+        );
+    }
+
+
+    public Integer methodThatThrowsChecked(String arg) throws Exception {
+        return arg.length();
+    }
+
+    @Test
+    public void givenOperationThatThrowsCheckedException_whenExecuteAndNeedToWrapCheckedIntoUnchecked_shouldPass() {
+        //when
+        List<Integer> collect = Stream.of("a", "b", "c").map(elem -> {
+            try {
+                return methodThatThrowsChecked(elem);
+            } catch (Exception e) {
+                e.printStackTrace();
+                throw new RuntimeException(e);
+            }
+        }).collect(Collectors.toList());
+
+        //then
+        assertEquals(
+                collect,
+                Arrays.asList(1, 1, 1)
+        );
+    }
+
+
+    @Test
+    public void givenOperationThatThrowsCheckedException_whenExecuteUsingUncheckedFuction_shouldPass() {
+        //when
+        List<Integer> collect = Stream.of("a", "b", "c")
+                .map(Unchecked.function(elem -> methodThatThrowsChecked(elem)))
+                .collect(Collectors.toList());
+
+        //then
+        assertEquals(
+                collect,
+                Arrays.asList(1, 1, 1)
+        );
+    }
+
+    @Test
+    public void givenFunction_whenAppliedPartially_shouldAddNumberToPartialArgument() {
+        //given
+        Function2<Integer, Integer, Integer> addTwoNumbers = (v1, v2) -> v1 + v2;
+        addTwoNumbers.toBiFunction();
+        Function1<Integer, Integer> addToTwo = addTwoNumbers.applyPartially(2);
+
+        //when
+        Integer result = addToTwo.apply(5);
+
+        //then
+        assertEquals(result, (Integer) 7);
+    }
+
+    @Test
+    public void givenSeqOfTuples_whenTransformToLowerNumberOfTuples_shouldHaveProperResult() {
+        //given
+        Seq<Tuple3<String, String, Integer>> personDetails = Seq.of(tuple("michael", "similar", 49), tuple("jodie", "variable", 43));
+        Tuple2<String, String> tuple = tuple("winter", "summer");
+
+        //when
+        List<Tuple4<String, String, String, String>> result = personDetails.map(t -> t.limit2().concat(tuple)).toList();
+
+        //then
+        assertEquals(
+          result,
+          Arrays.asList(tuple("michael", "similar", "winter", "summer"), tuple("jodie", "variable", "winter", "summer"))
+        );
+    }
+
+}

kotlin/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Introduction to the Kotlin Language](http://www.baeldung.com/kotlin)

libraries/pom.xml

@@ -0,0 +1,48 @@
+<?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>libraries</artifactId>
+    <name>libraries</name>
+    <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>
+        <!-- https://mvnrepository.com/artifact/cglib/cglib -->
+        <dependency>
+            <groupId>cglib</groupId>
+            <artifactId>cglib</artifactId>
+            <version>${cglib.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <cglib.version>3.2.4</cglib.version>
+        <junit.version>4.12</junit.version>
+    </properties>
+
+
+</project>

libraries/src/main/java/com/baeldung/cglib/mixin/Class1.java

@@ -0,0 +1,8 @@
+package com.baeldung.cglib.mixin;
+
+public class Class1 implements Interface1 {
+    @Override
+    public String first() {
+        return "first behaviour";
+    }
+}

libraries/src/main/java/com/baeldung/cglib/mixin/Class2.java

@@ -0,0 +1,8 @@
+package com.baeldung.cglib.mixin;
+
+public class Class2 implements Interface2 {
+    @Override
+    public String second() {
+        return "second behaviour";
+    }
+}

libraries/src/main/java/com/baeldung/cglib/mixin/Interface1.java

@@ -0,0 +1,5 @@
+package com.baeldung.cglib.mixin;
+
+public interface Interface1 {
+    String first();
+}

libraries/src/main/java/com/baeldung/cglib/mixin/Interface2.java

@@ -0,0 +1,5 @@
+package com.baeldung.cglib.mixin;
+
+public interface Interface2 {
+    String second();
+}

libraries/src/main/java/com/baeldung/cglib/mixin/MixinInterface.java

@@ -0,0 +1,4 @@
+package com.baeldung.cglib.mixin;
+
+public interface MixinInterface extends Interface1, Interface2 {
+}

libraries/src/main/java/com/baeldung/cglib/proxy/PersonService.java

@@ -0,0 +1,11 @@
+package com.baeldung.cglib.proxy;
+
+public class PersonService {
+    public String sayHello(String name) {
+        return "Hello " + name;
+    }
+
+    public Integer lengthOfName(String name) {
+        return name.length();
+    }
+}

libraries/src/test/java/com/baeldung/cglib/proxy/BeanGeneratorTest.java

@@ -0,0 +1,32 @@
+package com.baeldung.cglib.proxy;
+
+
+import net.sf.cglib.beans.BeanGenerator;
+import org.junit.Test;
+
+import java.lang.reflect.Method;
+
+import static junit.framework.TestCase.assertEquals;
+
+public class BeanGeneratorTest {
+
+    @Test
+    public void givenBeanCreator_whenAddProperty_thenClassShouldHaveFieldValue() throws Exception {
+        //given
+        BeanGenerator beanGenerator = new BeanGenerator();
+
+        //when
+        beanGenerator.addProperty("name", String.class);
+        Object myBean = beanGenerator.create();
+        Method setter = myBean
+                .getClass()
+                .getMethod("setName", String.class);
+        setter.invoke(myBean, "some string value set by a cglib");
+
+        //then
+        Method getter = myBean
+                .getClass()
+                .getMethod("getName");
+        assertEquals("some string value set by a cglib", getter.invoke(myBean));
+    }
+}

libraries/src/test/java/com/baeldung/cglib/proxy/MixinTest.java

@@ -0,0 +1,24 @@
+package com.baeldung.cglib.proxy;
+
+import com.baeldung.cglib.mixin.*;
+import net.sf.cglib.proxy.Mixin;
+import org.junit.Test;
+
+import static junit.framework.TestCase.assertEquals;
+
+public class MixinTest {
+
+    @Test
+    public void givenTwoClasses_whenMixedIntoOne_thenMixinShouldHaveMethodsFromBothClasses() throws Exception {
+        //when
+        Mixin mixin = Mixin.create(
+                new Class[]{Interface1.class, Interface2.class, MixinInterface.class},
+                new Object[]{new Class1(), new Class2()}
+        );
+        MixinInterface mixinDelegate = (MixinInterface) mixin;
+
+        //then
+        assertEquals("first behaviour", mixinDelegate.first());
+        assertEquals("second behaviour", mixinDelegate.second());
+    }
+}

libraries/src/test/java/com/baeldung/cglib/proxy/ProxyTest.java

@@ -0,0 +1,60 @@
+package com.baeldung.cglib.proxy;
+
+import net.sf.cglib.proxy.Enhancer;
+import net.sf.cglib.proxy.FixedValue;
+import net.sf.cglib.proxy.MethodInterceptor;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class ProxyTest {
+    @Test
+    public void givenPersonService_whenSayHello_thenReturnResult() {
+        //given
+        PersonService personService = new PersonService();
+
+        //when
+        String res = personService.sayHello("Tom");
+
+        //then
+        assertEquals(res, "Hello Tom");
+    }
+
+    @Test
+    public void givenEnhancerProxy_whenExtendPersonService_thenInterceptMethod() throws Exception {
+        //given
+        Enhancer enhancer = new Enhancer();
+        enhancer.setSuperclass(PersonService.class);
+        enhancer.setCallback((FixedValue) () -> "Hello Tom!");
+        PersonService proxy = (PersonService) enhancer.create();
+
+        //when
+        String res = proxy.sayHello(null);
+
+        //then
+        assertEquals("Hello Tom!", res);
+    }
+
+    @Test
+    public void givenEnhancer_whenExecuteMethodOnProxy_thenInterceptOnlyStringReturnTypeMethod() throws Exception {
+        //given
+        Enhancer enhancer = new Enhancer();
+        enhancer.setSuperclass(PersonService.class);
+        enhancer.setCallback((MethodInterceptor) (obj, method, args, proxy) -> {
+            if (method.getDeclaringClass() != Object.class && method.getReturnType() == String.class) {
+                return "Hello Tom!";
+            } else {
+                return proxy.invokeSuper(obj, args);
+            }
+        });
+
+        //when
+        PersonService proxy = (PersonService) enhancer.create();
+
+        //then
+        assertEquals("Hello Tom!", proxy.sayHello(null));
+        int lengthOfName = proxy.lengthOfName("Mary");
+        assertEquals(4, lengthOfName);
+    }
+
+}

log4j2/src/test/java/com/baeldung/logging/log4j2/tests/CustomLoggingTest.java

@@ -6,6 +6,7 @@ import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.sql.Connection;
 import java.sql.ResultSet;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.Marker;
@@ -25,83 +26,90 @@ public class CustomLoggingTest {
     public static void setup() throws Exception {
         Connection connection = ConnectionFactory.getConnection();
         connection.createStatement()
-            .execute("CREATE TABLE logs(" + "when TIMESTAMP," + "logger VARCHAR(255)," + "level VARCHAR(255)," + "message VARCHAR(4096)," + "throwable TEXT)");
+          .execute("CREATE TABLE logs(" + "when TIMESTAMP," + "logger VARCHAR(255)," + "level VARCHAR(255)," + "message VARCHAR(4096)," + "throwable TEXT)");
         connection.commit();
     }
 
     @Test
-    public void givenLoggerWithDefaultConfig_shouldLogToConsole() throws Exception {
+    public void givenLoggerWithDefaultConfig_whenLogToConsole_thanOK() throws Exception {
         Logger logger = LogManager.getLogger(getClass());
         Exception e = new RuntimeException("This is only a test!");
+
         logger.info("This is a simple message at INFO level. " + "It will be hidden.");
         logger.error("This is a simple message at ERROR level. " + "This is the minimum visible level.", e);
     }
 
     @Test
-    public void givenLoggerWithConsoleConfig_shouldLogToConsoleInColors() throws Exception {
+    public void givenLoggerWithConsoleConfig_whenLogToConsoleInColors_thanOK() throws Exception {
         Logger logger = LogManager.getLogger("CONSOLE_PATTERN_APPENDER_MARKER");
+        Exception e = new RuntimeException("This is only a test!");
+
         logger.trace("This is a colored message at TRACE level.");
         logger.debug("This is a colored message at DEBUG level. " + "This is the minimum visible level.");
         logger.info("This is a colored message at INFO level.");
         logger.warn("This is a colored message at WARN level.");
-        Exception e = new RuntimeException("This is only a test!");
         logger.error("This is a colored message at ERROR level.", e);
         logger.fatal("This is a colored message at FATAL level.");
     }
 
     @Test
-    public void givenLoggerWithConsoleConfig_shouldFilterByMarker() throws Exception {
+    public void givenLoggerWithConsoleConfig_whenFilterByMarker_thanOK() throws Exception {
         Logger logger = LogManager.getLogger("CONSOLE_PATTERN_APPENDER_MARKER");
         Marker appError = MarkerManager.getMarker("APP_ERROR");
-        logger.error(appError, "This marker message at ERROR level should be hidden.");
         Marker connectionTrace = MarkerManager.getMarker("CONN_TRACE");
+
+        logger.error(appError, "This marker message at ERROR level should be hidden.");
         logger.trace(connectionTrace, "This is a marker message at TRACE level.");
     }
 
     @Test
-    public void givenLoggerWithConsoleConfig_shouldFilterByThreadContext() throws Exception {
+    public void givenLoggerWithConsoleConfig_whenFilterByThreadContext_thanOK() throws Exception {
         Logger logger = LogManager.getLogger("CONSOLE_PATTERN_APPENDER_THREAD_CONTEXT");
         ThreadContext.put("userId", "1000");
         logger.info("This is a log-visible user login. Maybe from an admin account?");
         ThreadContext.put("userId", "1001");
         logger.info("This is a log-invisible user login.");
-
     }
 
     @Test
-    public void givenLoggerWithAsyncConfig_shouldLogToJsonFile() throws Exception {
+    public void givenLoggerWithAsyncConfig_whenLogToJsonFile_thanOK() throws Exception {
         Logger logger = LogManager.getLogger("ASYNC_JSON_FILE_APPENDER");
+
         final int count = 88;
         for (int i = 0; i < count; i++) {
             logger.info("This is async JSON message #{} at INFO level.", count);
         }
+
         long logEventsCount = Files.lines(Paths.get("target/logfile.json"))
-            .count();
+                .count();
         assertTrue(logEventsCount > 0 && logEventsCount <= count);
     }
 
     @Test
-    public void givenLoggerWithFailoverConfig_shouldLog() throws Exception {
+    public void givenLoggerWithFailoverConfig_whenLog_thanOK() throws Exception {
         Logger logger = LogManager.getLogger("FAIL_OVER_SYSLOG_APPENDER");
+        Exception e = new RuntimeException("This is only a test!");
+
         logger.trace("This is a syslog message at TRACE level.");
         logger.debug("This is a syslog message at DEBUG level.");
         logger.info("This is a syslog message at INFO level. This is the minimum visible level.");
         logger.warn("This is a syslog message at WARN level.");
-        Exception e = new RuntimeException("This is only a test!");
         logger.error("This is a syslog message at ERROR level.", e);
         logger.fatal("This is a syslog message at FATAL level.");
     }
 
     @Test
-    public void givenLoggerWithJdbcConfig_shouldLogToDataSource() throws Exception {
+    public void givenLoggerWithJdbcConfig_whenLogToDataSource_thanOK() throws Exception {
         Logger logger = LogManager.getLogger("JDBC_APPENDER");
+
         final int count = 88;
         for (int i = 0; i < count; i++) {
             logger.info("This is JDBC message #{} at INFO level.", count);
         }
         Connection connection = ConnectionFactory.getConnection();
         ResultSet resultSet = connection.createStatement()
-            .executeQuery("SELECT COUNT(*) AS ROW_COUNT FROM logs");
+          .executeQuery("SELECT COUNT(*) AS ROW_COUNT FROM logs");
+
         int logCount = 0;
         if (resultSet.next()) {
             logCount = resultSet.getInt("ROW_COUNT");
@@ -110,8 +118,9 @@ public class CustomLoggingTest {
     }
 
     @Test
-    public void givenLoggerWithRollingFileConfig_shouldLogToXMLFile() throws Exception {
+    public void givenLoggerWithRollingFileConfig_whenLogToXMLFile_thanOK() throws Exception {
         Logger logger = LogManager.getLogger("XML_ROLLING_FILE_APPENDER");
+
         final int count = 88;
         for (int i = 0; i < count; i++) {
             logger.info("This is rolling file XML message #{} at INFO level.", i);

log4j2/src/test/java/com/baeldung/logging/log4j2/tests/jdbc/ConnectionFactory.java

@@ -2,6 +2,7 @@ package com.baeldung.logging.log4j2.tests.jdbc;
 
 import org.apache.commons.dbcp2.BasicDataSource;
 import org.h2.Driver;
+
 import java.sql.Connection;
 import java.sql.SQLException;
 

log4j2/src/test/resources/log4j2.xml

@@ -19,12 +19,14 @@
         <Async name="AsyncAppender" bufferSize="80">
             <AppenderRef ref="JSONLogfileAppender" />
         </Async>
-        <Syslog name="Syslog" format="RFC5424" host="localhost" port="514" protocol="TCP" facility="local3" connectTimeoutMillis="10000" reconnectionDelayMillis="5000" />
+<!--
+        <Syslog name="Syslog" format="RFC5424" host="localhost" port="514" protocol="TCP" facility="local3" connectTimeoutMillis="10000" reconnectionDelayMillis="5000" mdcId="mdc" includeMDC="true" />
         <Failover name="FailoverAppender" primary="Syslog">
             <Failovers>
                 <AppenderRef ref="ConsoleAppender" />
             </Failovers>
         </Failover>
+-->
         <JDBC name="JDBCAppender" tableName="logs">
             <ConnectionFactory class="com.baeldung.logging.log4j2.tests.jdbc.ConnectionFactory" method="getConnection" />
             <Column name="when" isEventTimestamp="true" />
@@ -53,9 +55,11 @@
         <Logger name="ASYNC_JSON_FILE_APPENDER" level="INFO" additivity="false">
             <AppenderRef ref="AsyncAppender" />
         </Logger>
+<!--
         <Logger name="FAIL_OVER_SYSLOG_APPENDER" level="INFO" additivity="false">
             <AppenderRef ref="FailoverAppender" />
         </Logger>
+-->
         <Logger name="JDBC_APPENDER" level="INFO" additivity="false">
             <AppenderRef ref="JDBCAppender" />
         </Logger>

metrics/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Intro to Dropwizard Metrics](http://www.baeldung.com/dropwizard-metrics)

pdf/README.md

@@ -1,2 +1,3 @@
 ### Relevant Articles:
 - [PDF Conversions in Java](http://www.baeldung.com/pdf-conversions-java)
+- [Creating PDF Files in Java](http://www.baeldung.com/java-pdf-creation)

pom.xml

@@ -8,7 +8,6 @@
     <name>parent-modules</name>
     <packaging>pom</packaging>
 
-
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <gib.referenceBranch>refs/heads/master</gib.referenceBranch>
@@ -65,6 +64,7 @@
         <module>jaxb</module>
         <module>jee7</module>
         <module>jjwt</module>
+        <module>jooq</module>
         <module>jpa-storedprocedure</module>
         <module>jsf</module>
         <module>json-path</module>
@@ -74,6 +74,7 @@
 
         <module>kotlin</module>
 
+        <module>libraries</module>
         <module>log-mdc</module>
         <module>log4j</module>
         <module>log4j2</module>
@@ -93,6 +94,7 @@
         <module>querydsl</module>
 
         <!-- <module>raml</module> -->
+        <module>reactor-core</module>
         <module>redis</module>
         <module>rest-assured</module>
         <module>rest-testing</module>
@@ -109,6 +111,7 @@
         <module>spring-autowire</module>
         <module>spring-batch</module>
         <module>spring-boot</module>
+        <module>spring-boot-servlet</module>
         <module>spring-cloud-data-flow</module>
         <module>spring-cloud</module>
         <module>spring-core</module>
@@ -194,16 +197,20 @@
 
         <module>struts2</module>
         <module>apache-velocity</module>
+        <module>apache-solrj</module>
+
+        <module>rabbitmq</module>
+
 
     </modules>
 
     <build>
         <extensions>
-            <extension>
+            <!--<extension>
                 <groupId>com.vackosar.gitflowincrementalbuilder</groupId>
                 <artifactId>gitflow-incremental-builder</artifactId>
                 <version>3.1</version>
-            </extension>
+            </extension>-->
         </extensions>
     </build>
 </project>

rabbitmq/pom.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0"?>
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>rabbitmq</artifactId>
+    <version>0.1-SNAPSHOT</version>
+
+    <name>rabbitmq</name>
+    <url>http://maven.apache.org</url>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.rabbitmq</groupId>
+            <artifactId>amqp-client</artifactId>
+            <version>3.6.6</version>
+        </dependency>
+    </dependencies>
+    <build>
+        <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>
+            </plugins>
+
+        </pluginManagement>
+    </build>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+
+        <maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
+    </properties>
+
+</project>

rabbitmq/src/main/java/com/baeldung/consumer/Receiver.java

@@ -0,0 +1,31 @@
+package com.baeldung.consumer;
+
+import com.rabbitmq.client.*;
+
+import java.io.IOException;
+import java.util.concurrent.TimeoutException;
+
+public class Receiver {
+
+    private static final String QUEUE_NAME = "products_queue";
+
+    public static void main (String[] args) throws IOException, TimeoutException {
+        ConnectionFactory factory = new ConnectionFactory();
+        factory.setHost("localhost");
+        Connection connection = factory.newConnection();
+        Channel channel = connection.createChannel();
+
+        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
+
+        Consumer consumer = new DefaultConsumer(channel) {
+            @Override
+            public void handleDelivery(String consumerTag,
+                                       Envelope envelope, AMQP.BasicProperties properties,
+                                       byte[] body) throws IOException {
+                String message = new String(body, "UTF-8");
+                System.out.println(" [x] Received '" + message + "'");
+            }
+        };
+        channel.basicConsume(QUEUE_NAME, true, consumer);
+    }
+}

rabbitmq/src/main/java/com/baeldung/producer/Publisher.java

@@ -0,0 +1,27 @@
+package com.baeldung.producer;
+
+import com.rabbitmq.client.*;
+
+import java.io.IOException;
+import java.util.concurrent.TimeoutException;
+
+public class Publisher {
+
+    private final static String QUEUE_NAME = "products_queue";
+
+    public static void main(String[]args) throws IOException, TimeoutException {
+        ConnectionFactory factory = new ConnectionFactory();
+        factory.setHost("localhost");
+        Connection connection = factory.newConnection();
+        Channel channel = connection.createChannel();
+
+        String message = "product details";
+        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
+
+        channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
+        System.out.println(" [x] Sent '" + message + "'");
+
+        channel.close();
+        connection.close();
+    }
+}

reactor-core/pom.xml

@@ -0,0 +1,59 @@
+<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>org.baeldung</groupId>
+    <artifactId>reactor-core</artifactId>
+    <version>0.0.1-SNAPSHOT</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>io.projectreactor</groupId>
+            <artifactId>reactor-core</artifactId>
+            <version>${reactor-core.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>${logback.version}</version>
+        </dependency>
+
+    </dependencies>
+
+    <properties>
+        <reactor-core.version>3.0.4.RELEASE</reactor-core.version>
+        <junit.version>4.12</junit.version>
+        <assertj.version>3.6.1</assertj.version>
+        <logback.version>1.1.3</logback.version>
+    </properties>
+
+</project>

reactor-core/src/test/java/com/baeldung/reactor/ReactorTest.java

@@ -0,0 +1,122 @@
+package com.baeldung.reactor;
+
+import org.junit.Test;
+import org.reactivestreams.Subscriber;
+import org.reactivestreams.Subscription;
+import reactor.core.publisher.ConnectableFlux;
+import reactor.core.publisher.Flux;
+import reactor.core.scheduler.Schedulers;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class ReactorTest {
+
+    @Test
+    public void givenFlux_whenSubscribing_thenStream() throws InterruptedException {
+
+        List<Integer> elements = new ArrayList<>();
+
+        Flux.just(1, 2, 3, 4)
+                .log()
+                .map(i -> {
+                    System.out.println(i + ":" + Thread.currentThread());
+                    return i * 2;
+                })
+                .subscribe(elements::add);
+
+        assertThat(elements).containsExactly(2, 4, 6, 8);
+    }
+
+    @Test
+    public void givenFlux_whenZipping_thenCombine() {
+        List<String> elements = new ArrayList<>();
+
+        Flux.just(1, 2, 3, 4)
+                .log()
+                .map(i -> i * 2)
+                .zipWith(Flux.range(0, Integer.MAX_VALUE).log(), (two, one) -> String.format("First Flux: %d, Second Flux: %d", one, two))
+                .subscribe(elements::add);
+
+        assertThat(elements).containsExactly(
+                "First Flux: 0, Second Flux: 2",
+                "First Flux: 1, Second Flux: 4",
+                "First Flux: 2, Second Flux: 6",
+                "First Flux: 3, Second Flux: 8");
+    }
+
+    @Test
+    public void givenFlux_whenApplyingBackPressure_thenPushElementsInBatches() throws InterruptedException {
+
+        List<Integer> elements = new ArrayList<>();
+
+        Flux.just(1, 2, 3, 4)
+                .log()
+                .map(i -> i * 2)
+                .onBackpressureBuffer()
+                .subscribe(new Subscriber<Integer>() {
+                    private Subscription s;
+                    int onNextAmount;
+
+                    @Override
+                    public void onSubscribe(final Subscription s) {
+                        this.s = s;
+                        s.request(2);
+                    }
+
+                    @Override
+                    public void onNext(final Integer integer) {
+                        elements.add(integer);
+                        onNextAmount++;
+                        if (onNextAmount % 2 == 0) {
+                            s.request(2);
+                        }
+                    }
+
+                    @Override
+                    public void onError(final Throwable t) {
+                    }
+
+                    @Override
+                    public void onComplete() {
+                        int ham = 2;
+                    }
+                });
+
+        assertThat(elements).containsExactly(2, 4, 6, 8);
+    }
+
+    @Test
+    public void givenFlux_whenInParallel_thenSubscribeInDifferentThreads() throws InterruptedException {
+        List<String> threadNames = new ArrayList<>();
+
+        Flux.just(1, 2, 3, 4)
+                .log()
+                .map(i -> Thread.currentThread().getName())
+                .subscribeOn(Schedulers.parallel())
+                .subscribe(threadNames::add);
+
+        Thread.sleep(1000);
+
+        assertThat(threadNames).containsExactly("parallel-1", "parallel-1", "parallel-1", "parallel-1");
+    }
+
+    @Test
+    public void givenConnectableFlux_whenConnected_thenShouldStream() {
+
+        List<Integer> elements = new ArrayList<>();
+
+        final ConnectableFlux<Integer> publish = Flux.just(1, 2, 3, 4).publish();
+
+        publish.subscribe(elements::add);
+
+        assertThat(elements).isEmpty();
+
+        publish.connect();
+
+        assertThat(elements).containsExactly(1, 2, 3, 4);
+    }
+
+}

rxjava/README.md

@@ -0,0 +1,4 @@
+## Relevant articles:
+
+- [Dealing with Backpressure with RxJava](http://www.baeldung.com/rxjava-backpressure)
+- [How to Test RxJava?](http://www.baeldung.com/rxjava-testing)

solr-fulltext-search/pom.xml

@@ -18,7 +18,7 @@
         <dependency>
             <groupId>org.apache.solr</groupId>
             <artifactId>solr-solrj</artifactId>
-            <version>6.1.0</version>
+            <version>6.4.1</version>
         </dependency>
         <dependency>
             <groupId>log4j</groupId>

solr-fulltext-search/src/main/java/com/baeldung/solr/fulltext/search/model/Item.java

@@ -0,0 +1,51 @@
+package com.baeldung.solr.fulltext.search.model;
+
+import org.apache.solr.client.solrj.beans.Field;
+
+public class Item {
+
+    @Field
+    private String id;
+
+    @Field
+    private String description;
+
+    @Field
+    private String category;
+
+    @Field
+    private float price;
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    public String getCategory() {
+        return category;
+    }
+
+    public void setCategory(String category) {
+        this.category = category;
+    }
+
+    public float getPrice() {
+        return price;
+    }
+
+    public void setPrice(float price) {
+        this.price = price;
+    }
+
+}

solr-fulltext-search/src/main/java/com/baeldung/solr/fulltext/search/service/ItemSearchService.java

@@ -0,0 +1,15 @@
+package com.baeldung.solr.fulltext.search.service;
+
+import java.io.IOException;
+
+import org.apache.solr.client.solrj.SolrServerException;
+
+import com.baeldung.solr.fulltext.search.model.Item;
+
+public interface ItemSearchService {
+
+    public void index(String id, String description, String category, float price) throws SolrServerException, IOException;
+
+    public void indexBean(Item item) throws IOException, SolrServerException;
+
+}

solr-fulltext-search/src/main/java/com/baeldung/solr/fulltext/search/service/ItemSearchServiceImpl.java

@@ -0,0 +1,34 @@
+package com.baeldung.solr.fulltext.search.service;
+
+import java.io.IOException;
+
+import org.apache.solr.client.solrj.SolrClient;
+import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.common.SolrInputDocument;
+
+import com.baeldung.solr.fulltext.search.model.Item;
+
+public class ItemSearchServiceImpl implements ItemSearchService {
+
+    private final SolrClient solrClient;
+
+    public ItemSearchServiceImpl(SolrClient solrClient) {
+        this.solrClient = solrClient;
+    }
+
+    public void index(String id, String description, String category, float price) throws SolrServerException, IOException {
+        SolrInputDocument doc = new SolrInputDocument();
+        doc.addField("id", id);
+        doc.addField("description", description);
+        doc.addField("category", category);
+        doc.addField("price", price);
+        solrClient.add(doc);
+        solrClient.commit();
+    }
+
+    public void indexBean(Item item) throws IOException, SolrServerException {
+        solrClient.addBean(item);
+        solrClient.commit();
+    }
+
+}

solr-fulltext-search/src/test/java/com/baeldung/solr/fulltext/search/service/ItemSearchServiceIntegrationTest.java

@@ -0,0 +1,374 @@
+package com.baeldung.solr.fulltext.search.service;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+import java.util.List;
+import java.util.Map;
+
+import org.apache.solr.client.solrj.SolrClient;
+import org.apache.solr.client.solrj.SolrQuery;
+import org.apache.solr.client.solrj.impl.HttpSolrClient;
+import org.apache.solr.client.solrj.response.FacetField.Count;
+import org.apache.solr.client.solrj.response.QueryResponse;
+import org.apache.solr.client.solrj.response.RangeFacet;
+import org.apache.solr.client.solrj.response.SpellCheckResponse;
+import org.apache.solr.client.solrj.response.SpellCheckResponse.Suggestion;
+import org.apache.solr.client.solrj.response.SuggesterResponse;
+import org.apache.solr.common.SolrDocument;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import com.baeldung.solr.fulltext.search.model.Item;
+
+public class ItemSearchServiceIntegrationTest {
+
+    private static SolrClient solrClient;
+    private static ItemSearchService itemSearchService;
+    private static final String solrUrl = "http://localhost:8987/solr/item";
+
+    @BeforeClass
+    public static void initBeans() throws Exception {
+        solrClient = new HttpSolrClient.Builder(solrUrl).build();
+        itemSearchService = new ItemSearchServiceImpl(solrClient);
+
+        solrClient.commit();
+    }
+
+    @Before
+    public void clearSolrData() throws Exception {
+        solrClient.deleteByQuery("*:*");
+    }
+
+    @Test
+    public void whenIndexing_thenAvailableOnRetrieval() throws Exception {
+        itemSearchService.index("hm0001", "Washing Machine", "Home Appliances", 450f);
+        final SolrDocument indexedDoc = solrClient.getById("hm0001");
+        assertEquals("hm0001", indexedDoc.get("id"));
+    }
+
+    @Test
+    public void whenIndexingBean_thenAvailableOnRetrieval() throws Exception {
+        Item item = new Item();
+        item.setId("hm0002");
+        item.setCategory("Televisions");
+        item.setDescription("LED TV 32");
+        item.setPrice(500);
+        itemSearchService.indexBean(item);
+    }
+
+    @Test
+    public void whenSearchingByBasicQuery_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 450f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 450f);
+        itemSearchService.index("hm0003", "LED TV 32", "Brand1 Home Appliances", 450f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("brand1");
+        query.setStart(0);
+        query.setRows(10);
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(3, items.size());
+
+    }
+
+    @Test
+    public void whenSearchingWithWildCard_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 450f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 450f);
+        itemSearchService.index("hm0003", "LED TV 32", "Brand1 Home Appliances", 450f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("*rand?");
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(3, items.size());
+    }
+
+    @Test
+    public void whenSearchingWithLogicalOperators_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 450f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 450f);
+        itemSearchService.index("hm0003", "Brand2 LED TV 32", "Washing Appliances", 450f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("brand1 AND (Washing OR Refrigerator)");
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(2, items.size());
+    }
+
+    @Test
+    public void whenSearchingWithFields_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("0001", "Brand1 Washing Machine", "Home Appliances", 450f);
+        itemSearchService.index("0002", "Brand1 Refrigerator", "Home Appliances", 450f);
+        itemSearchService.index("0003", "Brand2 LED TV 32", "Brand1 Washing Home Appliances", 450f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("description:Brand* AND category:*Washing*");
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(1, items.size());
+    }
+
+    @Test
+    public void whenSearchingWithPhrase_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 450f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 450f);
+        itemSearchService.index("hm0003", "Brand2 Dishwasher", "Washing tools and equipment ", 450f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("washing MachIne");
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(2, items.size());
+    }
+
+    @Test
+    public void whenSearchingWithRealPhrase_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 450f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 450f);
+        itemSearchService.index("hm0003", "Brand2 Dishwasher", "Washing tools and equipment ", 450f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("\"washing machine\"");
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(1, items.size());
+    }
+
+    @Test
+    public void whenSearchingPhraseWithProximity_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 450f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 450f);
+        itemSearchService.index("hm0003", "Brand2 Dishwasher", "Washing tools and equipment ", 450f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("\"Washing equipment\"~2");
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(1, items.size());
+    }
+
+    @Test
+    public void whenSearchingWithPriceRange_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 100f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 300f);
+        itemSearchService.index("hm0003", "Brand2 Dishwasher", "Home Appliances", 200f);
+        itemSearchService.index("hm0004", "Brand2 Dishwasher", "Washing tools and equipment ", 450f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("price:[100 TO 300]");
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(3, items.size());
+    }
+
+    @Test
+    public void whenSearchingWithPriceRangeInclusiveExclusive_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 100f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 300f);
+        itemSearchService.index("hm0003", "Brand2 Dishwasher", "Home Appliances", 200f);
+        itemSearchService.index("hm0004", "Brand2 Dishwasher", "Washing tools and equipment ", 450f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("price:{100 TO 300]");
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(2, items.size());
+    }
+
+    @Test
+    public void whenSearchingWithFilterQuery_thenAllMatchingItemsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 100f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 300f);
+        itemSearchService.index("hm0003", "Brand2 Ceiling Fan", "Home Appliances", 200f);
+        itemSearchService.index("hm0004", "Brand2 Dishwasher", "Washing tools and equipment ", 250f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("price:[100 TO 300]");
+        query.addFilterQuery("description:Brand1", "category:Home Appliances");
+
+        QueryResponse response = solrClient.query(query);
+        List<Item> items = response.getBeans(Item.class);
+
+        assertEquals(2, items.size());
+    }
+
+    @Test
+    public void whenSearchingWithFacetFields_thenAllMatchingFacetsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "CategoryA", 100f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "CategoryA", 300f);
+        itemSearchService.index("hm0003", "Brand2 Ceiling Fan", "CategoryB", 200f);
+        itemSearchService.index("hm0004", "Brand2 Dishwasher", "CategoryB", 250f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("*:*");
+        query.addFacetField("category");
+
+        QueryResponse response = solrClient.query(query);
+        List<Count> facetResults = response.getFacetField("category").getValues();
+
+        assertEquals(2, facetResults.size());
+
+        for (Count count : facetResults) {
+            if ("categorya".equalsIgnoreCase(count.getName())) {
+                assertEquals(2, count.getCount());
+            } else if ("categoryb".equalsIgnoreCase(count.getName())) {
+                assertEquals(2, count.getCount());
+            } else {
+                fail("unexpected category");
+            }
+        }
+    }
+
+    @Test
+    public void whenSearchingWithFacetQuery_thenAllMatchingFacetsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "CategoryA", 100f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "CategoryA", 300f);
+        itemSearchService.index("hm0003", "Brand2 Ceiling Fan", "CategoryB", 200f);
+        itemSearchService.index("hm0004", "Brand2 Dishwasher", "CategoryB", 250f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("*:*");
+
+        query.addFacetQuery("Washing OR Refrigerator");
+        query.addFacetQuery("Brand2");
+
+        QueryResponse response = solrClient.query(query);
+        Map<String, Integer> facetQueryMap = response.getFacetQuery();
+
+        assertEquals(2, facetQueryMap.size());
+
+        for (Map.Entry<String, Integer> entry : facetQueryMap.entrySet()) {
+            String facetQuery = entry.getKey();
+
+            if ("Washing OR Refrigerator".equals(facetQuery)) {
+                assertEquals(Integer.valueOf(2), entry.getValue());
+            } else if ("Brand2".equals(facetQuery)) {
+                assertEquals(Integer.valueOf(2), entry.getValue());
+            } else {
+                fail("unexpected query");
+            }
+
+        }
+    }
+
+    @Test
+    public void whenSearchingWithFacetRange_thenAllMatchingFacetsShouldAvialble() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "CategoryA", 100f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "CategoryA", 125f);
+        itemSearchService.index("hm0003", "Brand2 Ceiling Fan", "CategoryB", 150f);
+        itemSearchService.index("hm0004", "Brand2 Dishwasher", "CategoryB", 250f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("*:*");
+
+        query.addNumericRangeFacet("price", 100, 275, 25);
+
+        QueryResponse response = solrClient.query(query);
+        List<RangeFacet> rangeFacets = response.getFacetRanges().get(0).getCounts();
+
+        assertEquals(7, rangeFacets.size());
+    }
+
+    @Test
+    public void whenSearchingWithHitHighlighting_thenKeywordsShouldBeHighlighted() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 100f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 300f);
+        itemSearchService.index("hm0003", "Brand2 Ceiling Fan", "Home Appliances", 200f);
+        itemSearchService.index("hm0004", "Brand2 Dishwasher", "Washing equipments", 250f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("Appliances");
+        query.setHighlight(true);
+        query.addHighlightField("category");
+        query.setHighlightSimplePre("<strong>");
+        query.setHighlightSimplePost("</strong>");
+        QueryResponse response = solrClient.query(query);
+
+        Map<String, Map<String, List<String>>> hitHighlightedMap = response.getHighlighting();
+        Map<String, List<String>> highlightedFieldMap = hitHighlightedMap.get("hm0001");
+        List<String> highlightedList = highlightedFieldMap.get("category");
+        String highLightedText = highlightedList.get(0);
+
+        assertEquals("Home <strong>Appliances</strong>", highLightedText);
+
+    }
+
+    @Test
+    public void whenSearchingWithKeywordWithMistake_thenSpellingSuggestionsShouldBeReturned() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 100f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 300f);
+        itemSearchService.index("hm0003", "Brand2 Ceiling Fan", "Home Appliances", 200f);
+        itemSearchService.index("hm0004", "Brand2 Dishwasher", "Washing equipments", 250f);
+
+        SolrQuery query = new SolrQuery();
+        query.setQuery("hme");
+        query.set("spellcheck", "on");
+        QueryResponse response = solrClient.query(query);
+
+        SpellCheckResponse spellCheckResponse = response.getSpellCheckResponse();
+
+        assertEquals(false, spellCheckResponse.isCorrectlySpelled());
+
+        Suggestion suggestion = spellCheckResponse.getSuggestions().get(0);
+
+        assertEquals("hme", suggestion.getToken());
+
+        List<String> alternatives = suggestion.getAlternatives();
+        String alternative = alternatives.get(0);
+
+        assertEquals("home", alternative);
+    }
+
+    @Test
+    public void whenSearchingWithIncompleteKeyword_thenKeywordSuggestionsShouldBeReturned() throws Exception {
+        itemSearchService.index("hm0001", "Brand1 Washing Machine", "Home Appliances", 100f);
+        itemSearchService.index("hm0002", "Brand1 Refrigerator", "Home Appliances", 300f);
+        itemSearchService.index("hm0003", "Brand2 Ceiling Fan", "Home Appliances", 200f);
+        itemSearchService.index("hm0004", "Brand2 Dishwasher", "Home washing equipments", 250f);
+
+        SolrQuery query = new SolrQuery();
+        query.setRequestHandler("/suggest");
+        query.set("suggest", "true");
+        query.set("suggest.build", "true");
+        query.set("suggest.dictionary", "mySuggester");
+        query.set("suggest.q", "Hom");
+        QueryResponse response = solrClient.query(query);
+
+        SuggesterResponse suggesterResponse = response.getSuggesterResponse();
+        Map<String, List<String>> suggestedTerms = suggesterResponse.getSuggestedTerms();
+        List<String> suggestions = suggestedTerms.get("mySuggester");
+
+        assertEquals(2, suggestions.size());
+
+        for (String term : suggestions) {
+            if (!"Home Appliances".equals(term) && !"Home washing equipments".equals(term)) {
+                fail("Unexpected suggestions");
+            }
+        }
+
+    }
+
+}

spring-5/.gitignore

@@ -0,0 +1,13 @@
+*.class
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear

spring-5/README.md

@@ -0,0 +1,6 @@
+## Spring REST Example Project
+
+###The Course
+The "REST With Spring" Classes: http://bit.ly/restwithspring
+
+### Relevant Articles:

spring-5/pom.xml

@@ -0,0 +1,116 @@
+<?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>spring-5</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>spring-5</name>
+    <description></description>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>2.0.0.BUILD-SNAPSHOT</version>
+        <relativePath /> <!-- lookup parent from repository -->
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-security</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <!-- utils -->
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+        </dependency>
+
+        <!-- runtime and test scoped -->
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-devtools</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+    <repositories>
+        <repository>
+            <id>spring-snapshots</id>
+            <name>Spring Snapshots</name>
+            <url>https://repo.spring.io/snapshot</url>
+            <snapshots>
+                <enabled>true</enabled>
+            </snapshots>
+        </repository>
+        <repository>
+            <id>spring-milestones</id>
+            <name>Spring Milestones</name>
+            <url>https://repo.spring.io/milestone</url>
+            <snapshots>
+                <enabled>false</enabled>
+            </snapshots>
+        </repository>
+    </repositories>
+    <pluginRepositories>
+        <pluginRepository>
+            <id>spring-snapshots</id>
+            <name>Spring Snapshots</name>
+            <url>https://repo.spring.io/snapshot</url>
+            <snapshots>
+                <enabled>true</enabled>
+            </snapshots>
+        </pluginRepository>
+        <pluginRepository>
+            <id>spring-milestones</id>
+            <name>Spring Milestones</name>
+            <url>https://repo.spring.io/milestone</url>
+            <snapshots>
+                <enabled>false</enabled>
+            </snapshots>
+        </pluginRepository>
+    </pluginRepositories>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+        <java.version>1.8</java.version>
+    </properties>
+
+</project>

spring-5/src/main/java/com/baeldung/Spring5Application.java

@@ -0,0 +1,13 @@
+package com.baeldung;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Spring5Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Spring5Application.class, args);
+    }
+
+}

spring-5/src/main/java/com/baeldung/persistence/DataSetupBean.java

@@ -0,0 +1,26 @@
+package com.baeldung.persistence;
+
+import static org.apache.commons.lang3.RandomStringUtils.randomAlphabetic;
+
+import java.util.stream.IntStream;
+
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import com.baeldung.web.Foo;
+
+@Component
+public class DataSetupBean implements InitializingBean {
+
+    @Autowired
+    private FooRepository repo;
+
+    //
+
+    @Override
+    public void afterPropertiesSet() throws Exception {
+        IntStream.range(1, 20).forEach(i -> repo.save(new Foo(randomAlphabetic(8))));
+    }
+
+}

spring-5/src/main/java/com/baeldung/persistence/FooRepository.java

@@ -0,0 +1,10 @@
+package com.baeldung.persistence;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
+
+import com.baeldung.web.Foo;
+
+public interface FooRepository extends JpaRepository<Foo, Long>, JpaSpecificationExecutor<Foo> {
+
+}

spring-5/src/main/java/com/baeldung/web/Foo.java

@@ -0,0 +1,84 @@
+package com.baeldung.web;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class Foo {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private long id;
+
+    private String name;
+
+    public Foo() {
+        super();
+    }
+
+    public Foo(final String name) {
+        super();
+
+        this.name = name;
+    }
+
+    public Foo(final long id, final String name) {
+        super();
+
+        this.id = id;
+        this.name = name;
+    }
+
+    // API
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(final long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(final String name) {
+        this.name = name;
+    }
+
+    //
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((name == null) ? 0 : name.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        Foo other = (Foo) obj;
+        if (name == null) {
+            if (other.name != null)
+                return false;
+        } else if (!name.equals(other.name))
+            return false;
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return "Foo [name=" + name + "]";
+    }
+
+}

spring-5/src/main/java/com/baeldung/web/FooController.java

@@ -0,0 +1,62 @@
+package com.baeldung.web;
+
+import java.util.List;
+
+import javax.validation.constraints.Max;
+import javax.validation.constraints.Min;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.http.HttpStatus;
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.persistence.FooRepository;
+
+@RestController("/foos")
+public class FooController {
+
+    @Autowired
+    private FooRepository repo;
+
+    // API - read
+
+    @RequestMapping(method = RequestMethod.GET, value = "/foos/{id}")
+    @ResponseBody
+    @Validated
+    public Foo findById(@PathVariable @Min(0) final long id) {
+        return repo.findOne(id);
+    }
+
+    @RequestMapping(method = RequestMethod.GET)
+    @ResponseBody
+    public List<Foo> findAll() {
+        return repo.findAll();
+    }
+
+    @RequestMapping(params = { "page", "size" }, method = RequestMethod.GET)
+    @ResponseBody
+    @Validated
+    public List<Foo> findPaginated(@RequestParam("page") @Min(0) final int page, @Max(100) @RequestParam("size") final int size) {
+        final Page<Foo> resultPage = repo.findAll(new PageRequest(page, size));
+        return resultPage.getContent();
+    }
+
+    // API - write
+
+    @RequestMapping(method = RequestMethod.PUT, value = "/foos/{id}")
+    @ResponseStatus(HttpStatus.OK)
+    @ResponseBody
+    public Foo update(@PathVariable("id") final String id, @RequestBody final Foo foo) {
+        return foo;
+    }
+
+}

spring-5/src/main/resources/application.properties

@@ -0,0 +1,6 @@
+server.port=8081
+
+security.user.name=user
+security.user.password=pass
+
+logging.level.root=INFO

spring-5/src/test/java/com/baeldung/IntegrationTestExample1.java

@@ -0,0 +1,29 @@
+package com.baeldung;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class IntegrationTestExample1 {
+
+    @Test
+    public void test1a() {
+        block(3000);
+    }
+
+    @Test
+    public void test1b() {
+        block(3000);
+    }
+
+    public static void block(long ms) {
+        try {
+            Thread.sleep(ms);
+        } catch (InterruptedException e) {
+            System.out.println("Thread interrupted");
+        }
+    }
+}

spring-5/src/test/java/com/baeldung/IntegrationTestExample2.java

@@ -0,0 +1,29 @@
+package com.baeldung;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class IntegrationTestExample2 {
+
+    @Test
+    public void test1a() {
+        block(3000);
+    }
+
+    @Test
+    public void test1b() {
+        block(3000);
+    }
+
+    public static void block(long ms) {
+        try {
+            Thread.sleep(ms);
+        } catch (InterruptedException e) {
+            System.out.println("Thread Interrupted");
+        }
+    }
+}

spring-5/src/test/java/com/baeldung/ParallelTestExample.java

@@ -0,0 +1,24 @@
+package com.baeldung;
+
+import org.junit.Test;
+import org.junit.experimental.ParallelComputer;
+import org.junit.runner.Computer;
+import org.junit.runner.JUnitCore;
+
+public class ParallelTestExample {
+
+    @Test
+    public void runTests() {
+        final Class<?>[] classes = { IntegrationTestExample1.class, IntegrationTestExample2.class };
+
+        JUnitCore.runClasses(new Computer(), classes);
+    }
+
+    @Test
+    public void runTestsInParallel() {
+        final Class<?>[] classes = { IntegrationTestExample1.class, IntegrationTestExample2.class };
+
+        JUnitCore.runClasses(new ParallelComputer(true, true), classes);
+    }
+
+}

spring-5/src/test/java/com/baeldung/Spring5ApplicationTests.java

@@ -0,0 +1,16 @@
+package com.baeldung;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class Spring5ApplicationTests {
+
+    @Test
+    public void contextLoads() {
+    }
+
+}

spring-all/README.md

@@ -16,3 +16,5 @@ The "REST With Spring" Classes: http://bit.ly/restwithspring
 - [Quick Guide to Spring Controllers](http://www.baeldung.com/spring-controllers)
 - [Quick Guide to Spring Bean Scopes](http://www.baeldung.com/spring-bean-scopes)
 - [Introduction To Ehcache](http://www.baeldung.com/ehcache)
+- [A Guide to the Spring Task Scheduler](http://www.baeldung.com/spring-task-scheduler)
+- [Guide to Spring Retry](http://www.baeldung.com/spring-retry)

spring-all/src/main/java/org/baeldung/bean/config/ConstructorBasedShipConfig.java

@@ -0,0 +1,20 @@
+package org.baeldung.bean.config;
+
+import org.baeldung.bean.injection.Helm;
+import org.baeldung.bean.injection.Ship;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class ConstructorBasedShipConfig {
+
+    @Bean
+    public Ship ship() {
+        return new Ship(helm());
+    }
+
+    @Bean
+    public Helm helm() {
+        return new Helm();
+    }
+}