Merge branch 'master' into sla-pr/1159-tim-doha

Conflicts:
	spring-cloud/spring-cloud-bootstrap/svc-book/pom.xml
	spring-cloud/spring-cloud-bootstrap/svc-book/src/main/java/com/baeldung/spring/cloud/bootstrap/svcbook/BookServiceApplication.java
	spring-cloud/spring-cloud-bootstrap/svc-rating/pom.xml
	spring-cloud/spring-cloud-bootstrap/svc-rating/src/main/java/com/baeldung/spring/cloud/bootstrap/svcrating/RatingServiceApplication.java

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>
-</project>
+	<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-bval/pom.xml

@@ -0,0 +1,51 @@
+<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>apache-bval</groupId>
+	<artifactId>apache-bval</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.apache.bval</groupId>
+			<artifactId>bval-jsr</artifactId>
+			<version>${bval.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>javax.validation</groupId>
+			<artifactId>validation-api</artifactId>
+			<version>1.1.0.Final</version>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.bval</groupId>
+			<artifactId>bval-extras</artifactId>
+			<version>${bval.version}</version>
+		</dependency>
+
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>${junit.version}</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>${maven-compiler-plugin.version}</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+	<properties>
+		<maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
+		<junit.version>4.12</junit.version>
+		<bval.version>1.1.2</bval.version>
+	</properties>
+</project>

apache-bval/src/main/java/com/baeldung/model/User.java

@@ -0,0 +1,120 @@
+package com.baeldung.model;
+
+import java.io.File;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+import javax.validation.constraints.Size;
+
+import org.apache.bval.constraints.Email;
+import org.apache.bval.constraints.NotEmpty;
+import org.apache.bval.extras.constraints.checkdigit.IBAN;
+import org.apache.bval.extras.constraints.creditcard.Visa;
+import org.apache.bval.extras.constraints.file.Directory;
+import org.apache.bval.extras.constraints.net.InetAddress;
+
+import com.baeldung.validation.Password;
+
+public class User {
+    @NotNull
+    @Email
+    private String email;
+
+    @NotEmpty
+    @Password
+    private String password;
+
+    @Size(min = 1, max = 20)
+    private String name;
+
+    @Min(18)
+    private int age;
+
+    @Visa
+    private String cardNumber = "";
+
+    @IBAN
+    private String iban = "";
+
+    @InetAddress
+    private String website = "";
+
+    @Directory
+    private File mainDirectory=new File(".");
+
+    public User() {
+    }
+
+    public User(String email, String password, String name, int age) {
+        super();
+        this.email = email;
+        this.password = password;
+        this.name = name;
+        this.age = age;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public String getCardNumber() {
+        return cardNumber;
+    }
+
+    public void setCardNumber(String cardNumber) {
+        this.cardNumber = cardNumber;
+    }
+
+    public String getIban() {
+        return iban;
+    }
+
+    public void setIban(String iban) {
+        this.iban = iban;
+    }
+
+    public String getWebsite() {
+        return website;
+    }
+
+    public void setWebsite(String website) {
+        this.website = website;
+    }
+
+    public File getMainDirectory() {
+        return mainDirectory;
+    }
+
+    public void setMainDirectory(File mainDirectory) {
+        this.mainDirectory = mainDirectory;
+    }
+
+}

apache-bval/src/main/java/com/baeldung/validation/Password.java

@@ -0,0 +1,25 @@
+package com.baeldung.validation;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import javax.validation.Constraint;
+import javax.validation.Payload;
+
+import static java.lang.annotation.ElementType.*;
+
+@Constraint(validatedBy = { PasswordValidator.class })
+@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Password {
+    String message() default "Invalid password";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+
+    int length() default 6;
+
+    int nonAlpha() default 1;
+}

apache-bval/src/main/java/com/baeldung/validation/PasswordValidator.java

@@ -0,0 +1,35 @@
+package com.baeldung.validation;
+
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+
+public class PasswordValidator implements ConstraintValidator<Password, String> {
+
+    private int length;
+    private int nonAlpha;
+
+    @Override
+    public void initialize(Password password) {
+        this.length = password.length();
+        this.nonAlpha = password.nonAlpha();
+
+    }
+
+    @Override
+    public boolean isValid(String value, ConstraintValidatorContext context) {
+        if (value.length() < length) {
+            return false;
+        }
+        int nonAlphaNr = 0;
+        for (int i = 0; i < value.length(); i++) {
+            if (!Character.isLetterOrDigit(value.charAt(i))) {
+                nonAlphaNr++;
+            }
+        }
+        if (nonAlphaNr < nonAlpha) {
+            return false;
+        }
+        return true;
+    }
+
+}

apache-bval/src/test/java/com/baeldung/validation/ValidationTest.java

@@ -0,0 +1,97 @@
+package com.baeldung.validation;
+
+import java.io.File;
+import java.util.Set;
+
+import javax.validation.ConstraintViolation;
+import javax.validation.Validation;
+import javax.validation.Validator;
+import javax.validation.ValidatorFactory;
+
+import org.apache.bval.jsr.ApacheValidationProvider;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+import com.baeldung.model.User;
+
+public class ValidationTest {
+    private static ValidatorFactory validatorFactory;
+    private static Validator validator;
+
+    @BeforeClass
+    public static void setup() {
+        validatorFactory = Validation.byProvider(ApacheValidationProvider.class)
+            .configure()
+            .buildValidatorFactory();
+        validator = validatorFactory.getValidator();
+    }
+
+    @Test
+    public void givenUser_whenValidate_thenValidationViolations() {
+        User user = new User("ana@yahoo.com", "pass", "nameTooLong_______________", 15);
+
+        Set<ConstraintViolation<User>> violations = validator.validate(user);
+        assertTrue("no violations", violations.size() > 0);
+    }
+	
+    @Test
+    public void givenInvalidAge_whenValidateProperty_thenConstraintViolation() {
+        User user = new User("ana@yahoo.com", "pass", "Ana", 12);
+
+        Set<ConstraintViolation<User>> propertyViolations = validator.validateProperty(user, "age");
+        assertEquals("size is not 1", 1, propertyViolations.size());
+    }
+	
+    @Test
+    public void givenValidAge_whenValidateValue_thenNoConstraintViolation() {
+        User user = new User("ana@yahoo.com", "pass", "Ana", 18);
+    
+        Set<ConstraintViolation<User>> valueViolations = validator.validateValue(User.class, "age", 20);
+        assertEquals("size is not 0", 0, valueViolations.size());
+    }
+
+    @Test
+    public void whenValidateNonJSR_thenCorrect() {
+        User user = new User("ana@yahoo.com", "pass", "Ana", 20);
+        user.setCardNumber("1234");
+        user.setIban("1234");
+        user.setWebsite("10.0.2.50");
+        user.setMainDirectory(new File("."));
+		
+        Set<ConstraintViolation<User>> violations = validator.validateProperty(user, "iban");
+        assertEquals("size is not 1", 1, violations.size());
+
+        violations = validator.validateProperty(user, "website");
+        assertEquals("size is not 0", 0, violations.size());
+
+        violations = validator.validateProperty(user, "mainDirectory");
+        assertEquals("size is not 0", 0, violations.size());
+    }
+
+    @Test
+    public void givenInvalidPassword_whenValidatePassword_thenConstraintViolation() {
+        User user = new User("ana@yahoo.com", "password", "Ana", 20);
+        Set<ConstraintViolation<User>> violations = validator.validateProperty(user, "password");
+        assertEquals("message incorrect", "Invalid password", violations.iterator()
+            .next()
+            .getMessage());
+    }
+	
+    @Test
+    public void givenValidPassword_whenValidatePassword_thenNoConstraintViolation() {
+        User user = new User("ana@yahoo.com", "password#", "Ana", 20);
+		
+        Set<ConstraintViolation<User>>  violations = validator.validateProperty(user, "password");
+        assertEquals("size is not 0", 0, violations.size());
+    }
+
+    @AfterClass
+    public static void close() {
+        if (validatorFactory != null) {
+            validatorFactory.close();
+        }
+    }
+}

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(1, docList.getNumFound());
+
+        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/junit4vstestng/DivisibilityTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.test.comparison;
+package com.baeldung.junit4vstestng;
 
 import static org.junit.Assert.assertEquals;
 
@@ -15,7 +15,7 @@ public class DivisibilityTest {
     }
 
     @Test
-    public void givenNumber_whenDivisiblebyTwo_thenCorrect() {
+    public void givenNumber_whenDivisibleByTwo_thenCorrect() {
         assertEquals(number % 2, 0);
     }
 }

core-java/src/test/java/com/baeldung/junit4vstestng/ParametrizedTests.java

@@ -0,0 +1,34 @@
+package com.baeldung.junit4vstestng;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameters;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+@RunWith(value = Parameterized.class)
+public class ParametrizedTests {
+
+    private int value;
+    private boolean isEven;
+
+    public ParametrizedTests(int value, boolean isEven) {
+        this.value = value;
+        this.isEven = isEven;
+    }
+
+    @Parameters
+    public static Collection<Object[]> data() {
+        Object[][] data = new Object[][]{{1, false}, {2, true}, {4, true}};
+        return Arrays.asList(data);
+    }
+
+    @Test
+    public void givenParametrizedNumber_ifEvenCheckOK_thenCorrect() {
+        Assert.assertEquals(isEven, value % 2 == 0);
+    }
+}

core-java/src/test/java/com/baeldung/junit4vstestng/RegistrationTest.java

@@ -0,0 +1,15 @@
+package com.baeldung.junit4vstestng;
+
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+public class RegistrationTest {
+    private static final Logger LOGGER = LoggerFactory.getLogger(RegistrationTest.class);
+
+    @Test
+    public void whenCalledFromSuite_thanOK() {
+        LOGGER.info("Registration successful");
+    }
+}

core-java/src/test/java/com/baeldung/junit4vstestng/SignInTest.java

@@ -0,0 +1,14 @@
+package com.baeldung.junit4vstestng;
+
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class SignInTest {
+    private static final Logger LOGGER = LoggerFactory.getLogger(SignInTest.class);
+
+    @Test
+    public void whenCalledFromSuite_thanOK() {
+        LOGGER.info("SignIn successful");
+    }
+}

core-java/src/test/java/com/baeldung/junit4vstestng/StringCaseTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.test.comparison;
+package com.baeldung.junit4vstestng;
 
 import static org.junit.Assert.assertEquals;
 

core-java/src/test/java/com/baeldung/junit4vstestng/SuiteTest.java

@@ -1,10 +1,10 @@
-package com.baeldung.test.comparison;
+package com.baeldung.junit4vstestng;
 
 import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
 
 @RunWith(Suite.class)
-@Suite.SuiteClasses({ StringCaseTest.class, DivisibilityTest.class })
+@Suite.SuiteClasses({ RegistrationTest.class, SignInTest.class })
 public class SuiteTest {
 
 }

core-java/src/test/java/com/baeldung/junit4vstestng/SummationServiceTest.java

@@ -1,8 +1,4 @@
-package com.baeldung.test.comparison;
+package com.baeldung.junit4vstestng;
-
-import java.security.Security;
-import java.util.ArrayList;
-import java.util.List;
 
 import org.junit.After;
 import org.junit.AfterClass;
@@ -12,6 +8,9 @@ import org.junit.BeforeClass;
 import org.junit.Ignore;
 import org.junit.Test;
 
+import java.util.ArrayList;
+import java.util.List;
+
 public class SummationServiceTest {
     private static List<Integer> numbers;
 

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());
+    }
+}

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

@@ -12,7 +12,7 @@ import com.baeldung.string.JoinerSplitter;
 public class JoinerSplitterTest {
 
 	@Test
-	public void givenArray_transformedToStream_convertToString() {
+	public void provided_array_convert_to_stream_and_convert_to_string() {
 
 		String[] programming_languages = {"java", "python", "nodejs", "ruby"};
 
@@ -24,6 +24,7 @@ public class JoinerSplitterTest {
 	
 	@Test
 	public void givenArray_transformedToStream_convertToPrefixPostfixString() {
+
 		String[] programming_languages = {"java", "python", 
 				"nodejs", "ruby"};
 		String expectation = "[java,python,nodejs,ruby]";
@@ -34,6 +35,7 @@ public class JoinerSplitterTest {
 	
 	@Test
 	public void givenString_transformedToStream_convertToList() {
+
 		String programming_languages = "java,python,nodejs,ruby";
 		
 		List<String> expectation = new ArrayList<String>();
@@ -49,6 +51,7 @@ public class JoinerSplitterTest {
   
 	@Test
 	public void givenString_transformedToStream_convertToListOfChar() {
+
 		String programming_languages = "java,python,nodejs,ruby";
 		
 		List<Character> expectation = new ArrayList<Character>();

core-java/src/test/java/com/baeldung/test/comparison/DependentTests.java

@@ -1,46 +0,0 @@
-package com.baeldung.test.comparison;
-
-import org.testng.Assert;
-import org.testng.annotations.BeforeClass;
-import org.testng.annotations.Test;
-
-public class DependentTests {
-
-    private EmailValidator emailValidator;
-    private LoginValidator loginValidator;
-    private String validEmail = "abc@qwe.com";
-
-    @BeforeClass
-    public void setup() {
-        emailValidator = new EmailValidator();
-        loginValidator = new LoginValidator();
-    }
-
-    @Test
-    public void givenEmail_ifValid_thenTrue() {
-        boolean valid = emailValidator.validate(validEmail);
-        Assert.assertEquals(valid, true);
-    }
-
-    @Test(dependsOnMethods = { "givenEmail_ifValid_thenTrue" })
-    public void givenValidEmail_whenLoggedin_thenTrue() {
-        boolean valid = loginValidator.validate();
-        Assert.assertEquals(valid, true);
-    }
-}
-
-class EmailValidator {
-
-    public boolean validate(String validEmail) {
-        return true;
-    }
-
-}
-
-class LoginValidator {
-
-    public boolean validate() {
-        return true;
-    }
-
-}

core-java/src/test/java/com/baeldung/test/comparison/MyParameterisedUnitTest.java

@@ -1,49 +0,0 @@
-package com.baeldung.test.comparison;
-
-import java.util.Arrays;
-import java.util.Collection;
-
-import org.junit.Assert;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.Parameterized;
-import org.junit.runners.Parameterized.Parameters;
-
-@RunWith(value = Parameterized.class)
-public class MyParameterisedUnitTest {
-
-    private String name;
-    private NameCheck nameCheck;
-
-    @Before
-    public void initialSetup() {
-        nameCheck = new NameCheck();
-    }
-
-    public MyParameterisedUnitTest(String myName) {
-        this.name = myName;
-    }
-
-    @Parameters
-    public static Collection<Object[]> data() {
-        Object[][] data = new Object[][] { { "Peter" }, { "Sam" }, { "Tim" }, { "Lucy" } };
-        return Arrays.asList(data);
-    }
-
-    @Test
-    public void givenName_whenValidLength_thenTrue() {
-        boolean valid = nameCheck.nameCheck(name);
-        Assert.assertEquals(valid, true);
-    }
-}
-
-class NameCheck {
-
-    public boolean nameCheck(String name) {
-        if (name.length() > 0)
-            return true;
-        return false;
-    }
-
-}

core-java/src/test/java/com/baeldung/test/comparison/MyParameterisedUnitTestNg.java

@@ -1,81 +0,0 @@
-package com.baeldung.test.comparison;
-
-import org.testng.Assert;
-import org.testng.annotations.BeforeClass;
-import org.testng.annotations.DataProvider;
-import org.testng.annotations.Parameters;
-import org.testng.annotations.Test;
-
-public class MyParameterisedUnitTestNg {
-
-    private PrimeNumberCheck primeNumberChecker;
-
-    @BeforeClass
-    public void intialSetup() {
-        primeNumberChecker = new PrimeNumberCheck();
-    }
-
-    @Test(enabled = false)
-    @Parameters({ "num", "expectedResult" })
-    public void givenNumber_ifPrime_thenCorrect(int number, boolean expectedResult) {
-        Assert.assertEquals(expectedResult, primeNumberChecker.validate(number));
-    }
-
-    @DataProvider(name = "test1")
-    public static Object[][] primeNumbers() {
-        return new Object[][] { { 2, true }, { 6, false }, { 19, true }, { 22, false }, { 23, true } };
-    }
-
-    @Test(dataProvider = "test1")
-    public void givenNumber_whenPrime_thenCorrect(Integer inputNumber, Boolean expectedResult) {
-        Assert.assertEquals(expectedResult, primeNumberChecker.validate(inputNumber));
-    }
-
-    @Test(dataProvider = "myDataProvider")
-    public void parameterCheckTest(User user) {
-        Assert.assertEquals("sam", user.getName());
-        Assert.assertEquals(12, user.getAge());
-    }
-
-    @DataProvider(name = "myDataProvider")
-    public Object[][] parameterProvider() {
-        User usr = new User();
-        usr.setName("sam");
-        usr.setAge(12);
-        return new Object[][] { { usr } };
-    }
-
-}
-
-class PrimeNumberCheck {
-
-    public Object validate(int number) {
-        for (int i = 2; i < number; i++) {
-            if (number % i == 0)
-                return false;
-        }
-        return true;
-    }
-
-}
-
-class User {
-    private String name;
-    private int age;
-
-    public String getName() {
-        return name;
-    }
-
-    public void setName(String name) {
-        this.name = name;
-    }
-
-    public int getAge() {
-        return age;
-    }
-
-    public void setAge(int age) {
-        this.age = age;
-    }
-}

core-java/src/test/java/com/baeldung/test/comparison/RegistrationTest.java

@@ -1,11 +0,0 @@
-package com.baeldung.test.comparison;
-
-import org.testng.annotations.Test;
-
-public class RegistrationTest {
-
-    @Test
-    public void givenEmail_ifValid_thenCorrect() {
-
-    }
-}

core-java/src/test/java/com/baeldung/test/comparison/SignInTest.java

@@ -1,12 +0,0 @@
-package com.baeldung.test.comparison;
-
-import org.testng.annotations.Test;
-
-public class SignInTest {
-
-    @Test
-    public void givenUsername_ifValid_thenCorrect() {
-
-    }
-
-}

core-java/src/test/resources/parameterised_test.xml

@@ -1,10 +0,0 @@
-<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
-<suite name="My test suite">
-    <test name="testing">
-       <parameter name="num" value="2"/>    
-       <parameter name="expectedResult" value="true"/>
-    <classes>
-        <class name="com.baeldung.test.comparison.MyParameterisedUnitTestNg"/>
-    </classes>
-    </test>
-</suite>

core-java/src/test/resources/test_group.xml

@@ -1,13 +0,0 @@
-<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
-<suite name="regression_test">
-<test name="testing">
-    <groups>
-        <run>
-            <include name="sanity" />
-        </run>
-    </groups>
-    <classes>
-        <class name="com.baeldung.test.comparison.SummationServiceTestTestNg" />
-    </classes>
-</test>
-</suite>

core-java/src/test/resources/test_suite.xml

@@ -1,9 +0,0 @@
-<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
-<suite name="Evaluation_Suite">
-    <test name="Sanity">
-        <classes>
-            <class name="com.baeldung.test.comparison.RegistrationTest" />
-            <class name="com.baeldung.test.comparison.SignInTest" />
-        </classes>
-    </test>
-</suite>

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/pom.xml

@@ -1,105 +1,104 @@
 <?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">
+	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>
+	<modelVersion>4.0.0</modelVersion>
 
-    <artifactId>log4j2</artifactId>
+	<artifactId>log4j2</artifactId>
 
-    <parent>
+	<parent>
-        <groupId>com.baeldung</groupId>
+		<groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
+		<artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
+		<version>1.0.0-SNAPSHOT</version>
-        <relativePath>..</relativePath>
+		<relativePath>..</relativePath>
-    </parent>
+	</parent>
 
-    <dependencies>
+	<dependencies>
-        <!-- This is the needed core component. -->
+		<!-- This is the needed core component. -->
-        <dependency>
+		<dependency>
-            <groupId>org.apache.logging.log4j</groupId>
+			<groupId>org.apache.logging.log4j</groupId>
-            <artifactId>log4j-core</artifactId>
+			<artifactId>log4j-core</artifactId>
-            <version>${log4j-core.version}</version>
+			<version>${log4j-core.version}</version>
-        </dependency>
+		</dependency>
 
-        <!-- This is used by JSONLayout. -->
+		<!-- This is used by JSONLayout. -->
-        <dependency>
+		<dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
+			<groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
+			<artifactId>jackson-databind</artifactId>
-            <version>${jackson.version}</version>
+			<version>${jackson.version}</version>
-        </dependency>
+		</dependency>
 
-        <!-- This is used by XMLLayout. -->
+		<!-- This is used by XMLLayout. -->
-        <dependency>
+		<dependency>
-            <groupId>com.fasterxml.jackson.dataformat</groupId>
+			<groupId>com.fasterxml.jackson.dataformat</groupId>
-            <artifactId>jackson-dataformat-xml</artifactId>
+			<artifactId>jackson-dataformat-xml</artifactId>
-            <version>${jackson.version}</version>
+			<version>${jackson.version}</version>
-        </dependency>
+		</dependency>
 
-        <!-- This is used by JDBC Appender. -->
+		<!-- This is used by JDBC Appender. -->
-        <dependency>
+		<dependency>
-            <groupId>com.h2database</groupId>
+			<groupId>com.h2database</groupId>
-            <artifactId>h2</artifactId>
+			<artifactId>h2</artifactId>
-            <version>${h2.version}</version>
+			<version>${h2.version}</version>
-        </dependency>
+		</dependency>
-        <dependency>
+		<dependency>
-            <groupId>org.apache.commons</groupId>
+			<groupId>org.apache.commons</groupId>
-            <artifactId>commons-dbcp2</artifactId>
+			<artifactId>commons-dbcp2</artifactId>
-            <version>${commons-dbcp2.version}</version>
+			<version>${commons-dbcp2.version}</version>
-        </dependency>
+		</dependency>
 
-        <!-- This is used for testing only. -->
+		<!-- This is used for testing only. -->
-        <dependency>
+		<dependency>
-            <groupId>org.apache.logging.log4j</groupId>
+			<groupId>org.apache.logging.log4j</groupId>
-            <artifactId>log4j-core</artifactId>
+			<artifactId>log4j-core</artifactId>
-            <version>${log4j-core.version}</version>
+			<version>${log4j-core.version}</version>
-            <type>test-jar</type>
+			<type>test-jar</type>
-            <scope>test</scope>
+			<scope>test</scope>
-        </dependency>
+		</dependency>
-        <dependency>
+		<dependency>
-            <groupId>junit</groupId>
+			<groupId>junit</groupId>
-            <artifactId>junit</artifactId>
+			<artifactId>junit</artifactId>
-            <version>${junit.version}</version>
+			<version>${junit.version}</version>
-            <scope>test</scope>
+			<scope>test</scope>
-        </dependency>
+		</dependency>
-    </dependencies>
+	</dependencies>
 
-    <build>
+	<build>
-        <plugins>
+		<plugins>
 
-            <plugin>
+			<plugin>
-                <groupId>org.apache.maven.plugins</groupId>
+				<groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
+				<artifactId>maven-compiler-plugin</artifactId>
-                <version>${maven-compiler-plugin.version}</version>
+				<version>${maven-compiler-plugin.version}</version>
-                <configuration>
+				<configuration>
-                    <source>1.8</source>
+					<source>1.8</source>
-                    <target>1.8</target>
+					<target>1.8</target>
-                </configuration>
+				</configuration>
-            </plugin>
+			</plugin>
-            <plugin>
+			<plugin>
-                <groupId>org.apache.maven.plugins</groupId>
+				<groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
+				<artifactId>maven-surefire-plugin</artifactId>
-                <version>${maven-surefire-plugin.version}</version>
+				<version>${maven-surefire-plugin.version}</version>
-                <configuration>
+				<configuration>
-                    <excludes>
+					<excludes>
-                        <exclude>**/*IntegrationTest.java</exclude>
+						<exclude>**/*IntegrationTest.java</exclude>
-                        <exclude>**/*LongRunningUnitTest.java</exclude>
+						<exclude>**/*LongRunningUnitTest.java</exclude>
-                        <exclude>**/*ManualTest.java</exclude>
+						<exclude>**/*ManualTest.java</exclude>
-                    </excludes>
+					</excludes>
-                    <testFailureIgnore>true</testFailureIgnore>
+					<testFailureIgnore>true</testFailureIgnore>
-                </configuration>
+				</configuration>
-            </plugin>
+			</plugin>
 
-        </plugins>
+		</plugins>
-    </build>
+	</build>
 
-    <properties>
+	<properties>
-        <jackson.version>2.8.5</jackson.version>
+		<jackson.version>2.8.5</jackson.version>
-        <h2.version>1.4.193</h2.version>
+		<h2.version>1.4.193</h2.version>
-        <commons-dbcp2.version>2.1.1</commons-dbcp2.version>
+		<commons-dbcp2.version>2.1.1</commons-dbcp2.version>
-        <log4j-core.version>2.7</log4j-core.version>
+		<log4j-core.version>2.7</log4j-core.version>
-        <junit.version>4.12</junit.version>
+		<junit.version>4.12</junit.version>
-        
+		<maven-compiler-plugin.version>3.6.0</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>
-        <maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
+	</properties>
-    </properties>
 
 </project>

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

@@ -1,32 +0,0 @@
-package com.baeldung.logging.log4j2.tests;
-
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.junit.LoggerContextRule;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
-import java.nio.file.Files;
-import java.nio.file.Paths;
-
-import static org.junit.Assert.assertTrue;
-
-@RunWith(JUnit4.class)
-public class AsyncFileAppenderUsingJsonLayoutTest {
-    @Rule
-    public LoggerContextRule contextRule =
-      new LoggerContextRule("log4j2-async-file-appender_json-layout.xml");
-
-    @Test
-    public void givenLoggerWithAsyncConfig_shouldLogToJsonFile()
-      throws Exception {
-        Logger logger = contextRule.getLogger(getClass().getSimpleName());
-        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();
-        assertTrue(logEventsCount > 0 && logEventsCount <= count);
-    }
-}

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

@@ -1,21 +0,0 @@
-package com.baeldung.logging.log4j2.tests;
-
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
-@RunWith(JUnit4.class)
-public class ConsoleAppenderUsingDefaultLayoutTest {
-    @Test
-    public void givenLoggerWithDefaultConfig_shouldLogToConsole()
-      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);
-    }
-}

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

@@ -1,51 +0,0 @@
-package com.baeldung.logging.log4j2.tests;
-
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.Marker;
-import org.apache.logging.log4j.MarkerManager;
-import org.apache.logging.log4j.ThreadContext;
-import org.apache.logging.log4j.junit.LoggerContextRule;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
-@RunWith(JUnit4.class)
-public class ConsoleAppenderUsingPatternLayoutWithColorsTest {
-    @Rule
-    public LoggerContextRule contextRule =
-      new LoggerContextRule("log4j2-console-appender_pattern-layout.xml");
-
-    @Test
-    public void givenLoggerWithConsoleConfig_shouldLogToConsoleInColors()
-      throws Exception {
-        Logger logger = contextRule.getLogger(getClass().getSimpleName());
-        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 {
-        Logger logger = contextRule.getLogger("ConnTrace");
-        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.trace(connectionTrace, "This is a marker message at TRACE level.");
-    }
-
-    @Test
-    public void givenLoggerWithConsoleConfig_shouldFilterByThreadContext() throws Exception {
-        Logger logger = contextRule.getLogger("UserAudit");
-        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.");
-        boolean b = true;
-    }
-}

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

@@ -0,0 +1,130 @@
+package com.baeldung.logging.log4j2.tests;
+
+import static org.junit.Assert.assertTrue;
+
+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;
+import org.apache.logging.log4j.MarkerManager;
+import org.apache.logging.log4j.ThreadContext;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import com.baeldung.logging.log4j2.tests.jdbc.ConnectionFactory;
+
+@RunWith(JUnit4.class)
+public class CustomLoggingTest {
+
+    @BeforeClass
+    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)");
+        connection.commit();
+    }
+
+    @Test
+    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_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.");
+        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_whenFilterByMarker_thanOK() throws Exception {
+        Logger logger = LogManager.getLogger("CONSOLE_PATTERN_APPENDER_MARKER");
+        Marker appError = MarkerManager.getMarker("APP_ERROR");
+        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_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_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();
+        assertTrue(logEventsCount > 0 && logEventsCount <= count);
+    }
+
+    @Test
+    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.");
+        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_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");
+
+        int logCount = 0;
+        if (resultSet.next()) {
+            logCount = resultSet.getInt("ROW_COUNT");
+        }
+        assertTrue(logCount == count);
+    }
+
+    @Test
+    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/FailoverSyslogConsoleAppenderTest.java

@@ -1,27 +0,0 @@
-package com.baeldung.logging.log4j2.tests;
-
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.junit.LoggerContextRule;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
-@RunWith(JUnit4.class)
-public class FailoverSyslogConsoleAppenderTest {
-    @Rule
-    public LoggerContextRule contextRule = 
-      new LoggerContextRule("log4j2-failover-syslog-console-appender_pattern-layout.xml");
-
-    @Test
-    public void givenLoggerWithFailoverConfig_shouldLog() throws Exception {
-        Logger logger = contextRule.getLogger(getClass().getSimpleName());
-        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.");
-    }
-}