Bael-624 - Code Review fixes

aws/src/main/java/com/baeldung/dynamodb/entity/ProductInfo.java

@@ -0,0 +1,51 @@
+package com.baeldung.dynamodb.entity;
+
+import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBAttribute;
+import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBAutoGeneratedKey;
+import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBHashKey;
+import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBTable;
+
+@DynamoDBTable(tableName = "ProductInfo")
+public class ProductInfo {
+
+    private String id;
+    private String msrp;
+    private String cost;
+
+    public ProductInfo() {
+    }
+
+    public ProductInfo(String cost, String msrp) {
+        this.msrp = msrp;
+        this.cost = cost;
+    }
+
+    @DynamoDBHashKey
+    @DynamoDBAutoGeneratedKey
+    public String getId() {
+        return id;
+    }
+
+    @DynamoDBAttribute
+    public String getMsrp() {
+        return msrp;
+    }
+
+    @DynamoDBAttribute
+    public String getCost() {
+        return cost;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public void setMsrp(String msrp) {
+        this.msrp = msrp;
+    }
+
+    public void setCost(String cost) {
+        this.cost = cost;
+    }
+
+}

aws/src/main/java/com/baeldung/dynamodb/repository/AbstractRepository.java

@@ -0,0 +1,49 @@
+package com.baeldung.dynamodb.repository;
+
+import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper;
+import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBScanExpression;
+
+import java.io.Serializable;
+import java.lang.reflect.ParameterizedType;
+import java.util.List;
+
+public abstract class AbstractRepository<T, ID extends Serializable> {
+
+    protected DynamoDBMapper mapper;
+    protected Class<T> entityClass;
+
+    protected AbstractRepository() {
+        ParameterizedType genericSuperclass = (ParameterizedType) getClass().getGenericSuperclass();
+
+        // This entityClass refers to the actual entity class in the subclass declaration.
+
+        // For instance, ProductInfoDAO extends AbstractDAO<ProductInfo, String>
+        // In this case entityClass = ProductInfo, and ID is String type
+        // which refers to the ProductInfo's partition key string value
+        this.entityClass = (Class<T>) genericSuperclass.getActualTypeArguments()[0];
+    }
+
+    public void save(T t) {
+        mapper.save(t);
+    }
+
+    public T findOne(ID id) {
+        return mapper.load(entityClass, id);
+    }
+
+    /**
+     * <strong>WARNING:</strong> It is not recommended to perform full table scan
+     * targeting the real production environment.
+     *
+     * @return All items
+     */
+    public List<T> findAll() {
+        DynamoDBScanExpression scanExpression = new DynamoDBScanExpression();
+        return mapper.scan(entityClass, scanExpression);
+    }
+
+    public void setMapper(DynamoDBMapper dynamoDBMapper) {
+        this.mapper = dynamoDBMapper;
+    }
+
+}

aws/src/main/java/com/baeldung/dynamodb/repository/ProductInfoRepository.java

@@ -0,0 +1,6 @@
+package com.baeldung.dynamodb.repository;
+
+import com.baeldung.dynamodb.entity.ProductInfo;
+
+public class ProductInfoRepository extends AbstractRepository<ProductInfo, String> {
+}

aws/src/main/java/com/baeldung/ec2/EC2Application.java

@@ -0,0 +1,137 @@
+package com.baeldung.ec2;
+
+import java.util.Arrays;
+
+import com.amazonaws.auth.AWSCredentials;
+import com.amazonaws.auth.AWSStaticCredentialsProvider;
+import com.amazonaws.auth.BasicAWSCredentials;
+import com.amazonaws.regions.Regions;
+import com.amazonaws.services.ec2.AmazonEC2;
+import com.amazonaws.services.ec2.AmazonEC2ClientBuilder;
+import com.amazonaws.services.ec2.model.AuthorizeSecurityGroupIngressRequest;
+import com.amazonaws.services.ec2.model.CreateKeyPairRequest;
+import com.amazonaws.services.ec2.model.CreateKeyPairResult;
+import com.amazonaws.services.ec2.model.CreateSecurityGroupRequest;
+import com.amazonaws.services.ec2.model.DescribeInstancesRequest;
+import com.amazonaws.services.ec2.model.DescribeInstancesResult;
+import com.amazonaws.services.ec2.model.DescribeKeyPairsRequest;
+import com.amazonaws.services.ec2.model.DescribeKeyPairsResult;
+import com.amazonaws.services.ec2.model.IpPermission;
+import com.amazonaws.services.ec2.model.IpRange;
+import com.amazonaws.services.ec2.model.MonitorInstancesRequest;
+import com.amazonaws.services.ec2.model.RebootInstancesRequest;
+import com.amazonaws.services.ec2.model.RunInstancesRequest;
+import com.amazonaws.services.ec2.model.StartInstancesRequest;
+import com.amazonaws.services.ec2.model.StopInstancesRequest;
+import com.amazonaws.services.ec2.model.UnmonitorInstancesRequest;
+
+public class EC2Application {
+
+    private static final AWSCredentials credentials;
+
+    static {
+        // put your accesskey and secretkey here
+        credentials = new BasicAWSCredentials(
+            "<AWS accesskey>", 
+            "<AWS secretkey>"
+        );
+    }
+
+    public static void main(String[] args) {
+       
+        // Set up the client
+        AmazonEC2 ec2Client = AmazonEC2ClientBuilder.standard()
+            .withCredentials(new AWSStaticCredentialsProvider(credentials))
+            .withRegion(Regions.US_EAST_1)
+            .build();
+
+        // Create a security group
+        CreateSecurityGroupRequest createSecurityGroupRequest = new CreateSecurityGroupRequest().withGroupName("BaeldungSecurityGroup")
+            .withDescription("Baeldung Security Group");
+        ec2Client.createSecurityGroup(createSecurityGroupRequest);
+
+        // Allow HTTP and SSH traffic
+        IpRange ipRange1 = new IpRange().withCidrIp("0.0.0.0/0");
+
+        IpPermission ipPermission1 = new IpPermission().withIpv4Ranges(Arrays.asList(new IpRange[] { ipRange1 }))
+            .withIpProtocol("tcp")
+            .withFromPort(80)
+            .withToPort(80);
+
+        IpPermission ipPermission2 = new IpPermission().withIpv4Ranges(Arrays.asList(new IpRange[] { ipRange1 }))
+            .withIpProtocol("tcp")
+            .withFromPort(22)
+            .withToPort(22);
+
+        AuthorizeSecurityGroupIngressRequest authorizeSecurityGroupIngressRequest = new AuthorizeSecurityGroupIngressRequest()
+            .withGroupName("BaeldungSecurityGroup")
+            .withIpPermissions(ipPermission1, ipPermission2);
+
+        ec2Client.authorizeSecurityGroupIngress(authorizeSecurityGroupIngressRequest);
+
+        // Create KeyPair
+        CreateKeyPairRequest createKeyPairRequest = new CreateKeyPairRequest()
+            .withKeyName("baeldung-key-pair");
+        CreateKeyPairResult createKeyPairResult = ec2Client.createKeyPair(createKeyPairRequest);
+        String privateKey = createKeyPairResult
+            .getKeyPair()
+            .getKeyMaterial(); // make sure you keep it, the private key, Amazon doesn't store the private key
+
+        // See what key-pairs you've got
+        DescribeKeyPairsRequest describeKeyPairsRequest = new DescribeKeyPairsRequest();
+        DescribeKeyPairsResult describeKeyPairsResult = ec2Client.describeKeyPairs(describeKeyPairsRequest);
+
+        // Launch an Amazon Instance
+        RunInstancesRequest runInstancesRequest = new RunInstancesRequest().withImageId("ami-97785bed") // https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AMIs.html | https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/usingsharedamis-finding.html
+            .withInstanceType("t2.micro") // https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html
+            .withMinCount(1)
+            .withMaxCount(1)
+            .withKeyName("baeldung-key-pair") // optional - if not present, can't connect to instance
+            .withSecurityGroups("BaeldungSecurityGroup");
+
+        String yourInstanceId = ec2Client.runInstances(runInstancesRequest).getReservation().getInstances().get(0).getInstanceId();
+
+        // Start an Instance
+        StartInstancesRequest startInstancesRequest = new StartInstancesRequest()
+            .withInstanceIds(yourInstanceId);
+
+        ec2Client.startInstances(startInstancesRequest);
+
+        // Monitor Instances
+        MonitorInstancesRequest monitorInstancesRequest = new MonitorInstancesRequest()
+            .withInstanceIds(yourInstanceId);
+
+        ec2Client.monitorInstances(monitorInstancesRequest);
+
+        UnmonitorInstancesRequest unmonitorInstancesRequest = new UnmonitorInstancesRequest()
+            .withInstanceIds(yourInstanceId);
+
+        ec2Client.unmonitorInstances(unmonitorInstancesRequest);
+
+        // Reboot an Instance
+
+        RebootInstancesRequest rebootInstancesRequest = new RebootInstancesRequest()
+            .withInstanceIds(yourInstanceId);
+
+        ec2Client.rebootInstances(rebootInstancesRequest);
+
+        // Stop an Instance
+        StopInstancesRequest stopInstancesRequest = new StopInstancesRequest()
+            .withInstanceIds(yourInstanceId);
+
+        ec2Client.stopInstances(stopInstancesRequest)
+            .getStoppingInstances()
+            .get(0)
+            .getPreviousState()
+            .getName();
+
+        // Describe an Instance
+        DescribeInstancesRequest describeInstancesRequest = new DescribeInstancesRequest();
+        DescribeInstancesResult response = ec2Client.describeInstances(describeInstancesRequest);
+        System.out.println(response.getReservations()
+            .get(0)
+            .getInstances()
+            .get(0)
+            .getKernelId());
+    }
+}

aws/src/main/java/com/baeldung/rds/AWSRDSService.java

@@ -0,0 +1,184 @@
+package com.baeldung.rds;
+
+import com.amazonaws.auth.AWSCredentialsProvider;
+import com.amazonaws.auth.AWSStaticCredentialsProvider;
+import com.amazonaws.auth.BasicAWSCredentials;
+import com.amazonaws.regions.Regions;
+import com.amazonaws.services.rds.AmazonRDS;
+import com.amazonaws.services.rds.AmazonRDSClientBuilder;
+import com.amazonaws.services.rds.model.*;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.sql.*;
+import java.util.List;
+import java.util.Properties;
+import java.util.UUID;
+import java.util.logging.Logger;
+
+public class AWSRDSService {
+
+
+    final static Logger logger = Logger.getLogger(AWSRDSService.class.getName());
+    private AWSCredentialsProvider credentials;
+    private AmazonRDS amazonRDS;
+    private String db_username;
+    private String db_password;
+    private String db_database;
+    private String db_hostname;
+
+    /*
+    * User access key and secret key must be set before execute any operation.
+    * Follow the link on how to get the user access and secret key
+    * https://aws.amazon.com/blogs/security/wheres-my-secret-access-key/
+    * **/
+    public AWSRDSService() throws IOException {
+        //Init RDS client with credentials and region.
+        credentials = new
+                AWSStaticCredentialsProvider(new
+                BasicAWSCredentials("<ACCESS_KEY>",
+                "<SECRET_KEY>"));
+        amazonRDS = AmazonRDSClientBuilder.standard().withCredentials(credentials)
+                .withRegion(Regions.AP_SOUTHEAST_2).build();
+        Properties prop = new Properties();
+        InputStream input = AWSRDSService.class.getClassLoader().getResourceAsStream("db.properties");
+        prop.load(input);
+        db_username = prop.getProperty("db_username");
+        db_password = prop.getProperty("db_password");
+        db_database = prop.getProperty("db_database");
+    }
+
+    public AWSRDSService(AmazonRDS amazonRDS){
+        this.amazonRDS = amazonRDS;
+    }
+
+    /**
+     * create the RDS instance.
+     * After instance creation, update the db_hostname with endpoint in db.properties.
+     * */
+
+    public String launchInstance() {
+
+        String identifier = "";
+        CreateDBInstanceRequest request = new CreateDBInstanceRequest();
+        // RDS instance name
+        request.setDBInstanceIdentifier("Sydney");
+        request.setEngine("postgres");
+        request.setMultiAZ(false);
+        request.setMasterUsername(db_username);
+        request.setMasterUserPassword(db_password);
+        request.setDBName(db_database);
+        request.setStorageType("gp2");
+        request.setAllocatedStorage(10);
+
+        DBInstance instance = amazonRDS.createDBInstance(request);
+
+        // Information about the new RDS instance
+        identifier = instance.getDBInstanceIdentifier();
+        String status = instance.getDBInstanceStatus();
+        Endpoint endpoint = instance.getEndpoint();
+        String endpoint_url = "Endpoint URL not available yet.";
+        if (endpoint != null) {
+            endpoint_url = endpoint.toString();
+        }
+        logger.info(identifier + "\t" + status);
+        logger.info(endpoint_url);
+
+        return identifier;
+
+    }
+
+    // Describe DB instances
+    public void listInstances() {
+        DescribeDBInstancesResult result = amazonRDS.describeDBInstances();
+        List<DBInstance> instances = result.getDBInstances();
+        for (DBInstance instance : instances) {
+            // Information about each RDS instance
+            String identifier = instance.getDBInstanceIdentifier();
+            String engine = instance.getEngine();
+            String status = instance.getDBInstanceStatus();
+            Endpoint endpoint = instance.getEndpoint();
+            String endpoint_url = "Endpoint URL not available yet.";
+            if (endpoint != null) {
+                endpoint_url = endpoint.toString();
+            }
+            logger.info(identifier + "\t" + engine + "\t" + status);
+            logger.info("\t" + endpoint_url);
+        }
+
+    }
+
+    //Delete RDS instance
+    public void terminateInstance(String identifier) {
+
+        DeleteDBInstanceRequest request = new DeleteDBInstanceRequest();
+        request.setDBInstanceIdentifier(identifier);
+        request.setSkipFinalSnapshot(true);
+
+        // Delete the RDS instance
+        DBInstance instance = amazonRDS.deleteDBInstance(request);
+
+        // Information about the RDS instance being deleted
+        String status = instance.getDBInstanceStatus();
+        Endpoint endpoint = instance.getEndpoint();
+        String endpoint_url = "Endpoint URL not available yet.";
+        if (endpoint != null) {
+            endpoint_url = endpoint.toString();
+        }
+
+        logger.info(identifier + "\t" + status);
+        logger.info(endpoint_url);
+
+    }
+
+
+    public void runJdbcTests() throws SQLException, IOException {
+
+        // Getting database properties from db.properties
+        Properties prop = new Properties();
+        InputStream input = AWSRDSService.class.getClassLoader().getResourceAsStream("db.properties");
+        prop.load(input);
+        db_hostname = prop.getProperty("db_hostname");
+        String jdbc_url = "jdbc:postgresql://" + db_hostname + ":5432/" + db_database;
+
+        // Create a connection using the JDBC driver
+        try (Connection conn = DriverManager.getConnection(jdbc_url, db_username, db_password)) {
+
+            // Create the test table if not exists
+            Statement statement = conn.createStatement();
+            String sql = "CREATE TABLE IF NOT EXISTS jdbc_test (id SERIAL PRIMARY KEY, content VARCHAR(80))";
+            statement.executeUpdate(sql);
+
+            // Do some INSERT
+            PreparedStatement preparedStatement = conn.prepareStatement("INSERT INTO jdbc_test (content) VALUES (?)");
+            String content = "" + UUID.randomUUID();
+            preparedStatement.setString(1, content);
+            preparedStatement.executeUpdate();
+            logger.info("INSERT: " + content);
+
+            // Do some SELECT
+            sql = "SELECT  * FROM jdbc_test";
+            ResultSet resultSet = statement.executeQuery(sql);
+            while (resultSet.next()) {
+                String count = resultSet.getString("content");
+                logger.info("Total Records: " + count);
+            }
+        }
+
+
+    }
+
+    public static void main(String[] args) throws IOException, SQLException {
+        AWSRDSService awsrdsService = new AWSRDSService();
+
+        String instanceName = awsrdsService.launchInstance();
+
+        //Add some wait for instance creation.
+
+        awsrdsService.listInstances();
+
+        awsrdsService.runJdbcTests();
+
+        awsrdsService.terminateInstance(instanceName);
+    }
+}

aws/src/main/java/com/baeldung/s3/AWSS3Service.java

@@ -0,0 +1,87 @@
+package com.baeldung.s3;
+
+import java.io.File;
+import java.util.List;
+
+import com.amazonaws.services.s3.AmazonS3;
+import com.amazonaws.services.s3.AmazonS3Client;
+import com.amazonaws.services.s3.model.Bucket;
+import com.amazonaws.services.s3.model.CopyObjectResult;
+import com.amazonaws.services.s3.model.DeleteObjectsRequest;
+import com.amazonaws.services.s3.model.DeleteObjectsResult;
+import com.amazonaws.services.s3.model.ObjectListing;
+import com.amazonaws.services.s3.model.PutObjectResult;
+import com.amazonaws.services.s3.model.S3Object;
+
+public class AWSS3Service {
+    private final AmazonS3 s3client;
+
+    public AWSS3Service() { 
+        this(new AmazonS3Client() {
+        }); 
+    } 
+    
+    public AWSS3Service(AmazonS3 s3client) {
+        this.s3client = s3client;
+    }
+    
+    //is bucket exist?
+    public boolean doesBucketExist(String bucketName) { 
+        return s3client.doesBucketExist(bucketName); 
+    } 
+    
+    //create a bucket
+    public Bucket createBucket(String bucketName) { 
+        return s3client.createBucket(bucketName); 
+    } 
+
+    //list all buckets
+    public List<Bucket> listBuckets() { 
+        return s3client.listBuckets(); 
+    }
+
+    //delete a bucket
+    public void deleteBucket(String bucketName) { 
+        s3client.deleteBucket(bucketName); 
+    }  
+    
+    //uploading object
+    public PutObjectResult putObject(String bucketName, String key, File file) {
+        return s3client.putObject(bucketName, key, file);
+    }
+    
+    //listing objects
+    public ObjectListing listObjects(String bucketName) {
+        return s3client.listObjects(bucketName);
+    }
+    
+    //get an object
+    public S3Object getObject(String bucketName, String objectKey) {
+        return s3client.getObject(bucketName, objectKey);
+    } 
+    
+    //copying an object
+    public CopyObjectResult copyObject(
+      String sourceBucketName,
+      String sourceKey,
+      String destinationBucketName,
+      String destinationKey
+    ) {
+        return s3client.copyObject(
+          sourceBucketName, 
+          sourceKey, 
+          destinationBucketName, 
+          destinationKey
+        );
+    }
+    
+    //deleting an object
+    public void deleteObject(String bucketName, String objectKey) {
+        s3client.deleteObject(bucketName, objectKey);
+    }
+    
+    //deleting multiple Objects
+    public DeleteObjectsResult deleteObjects(DeleteObjectsRequest delObjReq) {
+        return s3client.deleteObjects(delObjReq);
+    }
+}

aws/src/main/java/com/baeldung/s3/MultipartUpload.java

@@ -0,0 +1,56 @@
+package com.baeldung.s3;
+
+import com.amazonaws.AmazonClientException;
+import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
+import com.amazonaws.event.ProgressListener;
+import com.amazonaws.regions.Regions;
+import com.amazonaws.services.s3.AmazonS3;
+import com.amazonaws.services.s3.AmazonS3ClientBuilder;
+import com.amazonaws.services.s3.model.PutObjectRequest;
+import com.amazonaws.services.s3.transfer.TransferManager;
+import com.amazonaws.services.s3.transfer.TransferManagerBuilder;
+import com.amazonaws.services.s3.transfer.Upload;
+
+import java.io.File;
+import java.util.concurrent.Executors;
+
+public class MultipartUpload {
+
+    public static void main(String[] args) throws Exception {
+        String existingBucketName = "baeldung-bucket";
+        String keyName = "my-picture.jpg";
+        String filePath = "documents/my-picture.jpg";
+
+        AmazonS3 amazonS3 = AmazonS3ClientBuilder
+                .standard()
+                .withCredentials(new DefaultAWSCredentialsProviderChain())
+                .withRegion(Regions.DEFAULT_REGION)
+                .build();
+
+        int maxUploadThreads = 5;
+
+        TransferManager tm = TransferManagerBuilder
+                .standard()
+                .withS3Client(amazonS3)
+                .withMultipartUploadThreshold((long) (5 * 1024 * 1024))
+                .withExecutorFactory(() -> Executors.newFixedThreadPool(maxUploadThreads))
+                .build();
+
+        ProgressListener progressListener =
+                progressEvent -> System.out.println("Transferred bytes: " + progressEvent.getBytesTransferred());
+
+        PutObjectRequest request = new PutObjectRequest(existingBucketName, keyName, new File(filePath));
+
+        request.setGeneralProgressListener(progressListener);
+
+        Upload upload = tm.upload(request);
+
+        try {
+            upload.waitForCompletion();
+            System.out.println("Upload complete.");
+        } catch (AmazonClientException e) {
+            System.out.println("Error occurred while uploading file");
+            e.printStackTrace();
+        }
+    }
+}

aws/src/main/java/com/baeldung/s3/S3Application.java

@@ -0,0 +1,101 @@
+package com.baeldung.s3;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.apache.commons.io.FileUtils;
+
+import com.amazonaws.auth.AWSCredentials;
+import com.amazonaws.auth.AWSStaticCredentialsProvider;
+import com.amazonaws.auth.BasicAWSCredentials;
+import com.amazonaws.regions.Regions;
+import com.amazonaws.services.s3.AmazonS3;
+import com.amazonaws.services.s3.AmazonS3ClientBuilder;
+import com.amazonaws.services.s3.model.Bucket;
+import com.amazonaws.services.s3.model.DeleteObjectsRequest;
+import com.amazonaws.services.s3.model.ObjectListing;
+import com.amazonaws.services.s3.model.S3Object;
+import com.amazonaws.services.s3.model.S3ObjectInputStream;
+import com.amazonaws.services.s3.model.S3ObjectSummary;
+
+public class S3Application {
+
+    private static final AWSCredentials credentials;
+    private static String bucketName;  
+
+    static {
+        //put your accesskey and secretkey here
+        credentials = new BasicAWSCredentials(
+          "<AWS accesskey>", 
+          "<AWS secretkey>"
+        );
+    }
+    
+    public static void main(String[] args) throws IOException {
+        //set-up the client
+        AmazonS3 s3client = AmazonS3ClientBuilder
+          .standard()
+          .withCredentials(new AWSStaticCredentialsProvider(credentials))
+          .withRegion(Regions.US_EAST_2)
+          .build();
+        
+        AWSS3Service awsService = new AWSS3Service(s3client);
+
+        bucketName = "baeldung-bucket";
+
+        //creating a bucket
+        if(awsService.doesBucketExist(bucketName)) {
+            System.out.println("Bucket name is not available."
+              + " Try again with a different Bucket name.");
+            return;
+        }
+        awsService.createBucket(bucketName);
+        
+        //list all the buckets
+        for(Bucket s : awsService.listBuckets() ) {
+            System.out.println(s.getName());
+        }
+        
+        //deleting bucket
+        awsService.deleteBucket("baeldung-bucket-test2");
+        
+        //uploading object
+        awsService.putObject(
+          bucketName, 
+          "Document/hello.txt",
+          new File("/Users/user/Document/hello.txt")
+        );
+
+        //listing objects
+        ObjectListing objectListing = awsService.listObjects(bucketName);
+        for(S3ObjectSummary os : objectListing.getObjectSummaries()) {
+            System.out.println(os.getKey());
+        }
+
+        //downloading an object
+        S3Object s3object = awsService.getObject(bucketName, "Document/hello.txt");
+        S3ObjectInputStream inputStream = s3object.getObjectContent();
+        FileUtils.copyInputStreamToFile(inputStream, new File("/Users/user/Desktop/hello.txt"));
+        
+        //copying an object
+        awsService.copyObject(
+          "baeldung-bucket", 
+          "picture/pic.png", 
+          "baeldung-bucket2", 
+          "Document/picture.png"
+        );
+        
+        //deleting an object
+        awsService.deleteObject(bucketName, "Document/hello.txt");
+
+        //deleting multiple objects
+        String objkeyArr[] = {
+          "Document/hello2.txt", 
+          "Document/picture.png"
+        };
+        
+        DeleteObjectsRequest delObjReq = new DeleteObjectsRequest("baeldung-bucket")
+          .withKeys(objkeyArr);
+        awsService.deleteObjects(delObjReq);
+    }
+}

aws/src/main/java/com/baeldung/sqs/SQSApplication.java

@@ -0,0 +1,146 @@
+package com.baeldung.sqs;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.amazonaws.auth.AWSCredentials;
+import com.amazonaws.auth.AWSStaticCredentialsProvider;
+import com.amazonaws.auth.BasicAWSCredentials;
+import com.amazonaws.regions.Regions;
+import com.amazonaws.services.sqs.AmazonSQSClientBuilder;
+import com.amazonaws.services.sqs.model.CreateQueueRequest;
+import com.amazonaws.services.sqs.model.DeleteMessageRequest;
+import com.amazonaws.services.sqs.model.GetQueueAttributesRequest;
+import com.amazonaws.services.sqs.model.GetQueueAttributesResult;
+import com.amazonaws.services.sqs.model.MessageAttributeValue;
+import com.amazonaws.services.sqs.model.ReceiveMessageRequest;
+import com.amazonaws.services.sqs.model.SendMessageBatchRequest;
+import com.amazonaws.services.sqs.model.SendMessageRequest;
+import com.amazonaws.services.sqs.model.SetQueueAttributesRequest;
+import com.amazonaws.services.sqs.model.SendMessageBatchRequestEntry;
+import com.amazonaws.services.sqs.model.Message;
+import com.amazonaws.services.sqs.AmazonSQS;
+
+public class SQSApplication {
+
+    private static final AWSCredentials credentials;
+
+    static {
+        // put your accesskey and secretkey here
+        credentials = new BasicAWSCredentials(
+            "<AWS accesskey>", 
+            "<AWS secretkey>"
+        );
+    }
+
+    public static void main(String[] args) {
+
+        // Set up the client
+        AmazonSQS sqs = AmazonSQSClientBuilder.standard()
+            .withCredentials(new AWSStaticCredentialsProvider(credentials))
+            .withRegion(Regions.US_EAST_1)
+            .build();
+
+        // Create a standard queue
+
+        CreateQueueRequest createStandardQueueRequest = new CreateQueueRequest("baeldung-queue");
+        String standardQueueUrl = sqs.createQueue(createStandardQueueRequest)
+            .getQueueUrl();
+
+        System.out.println(standardQueueUrl);
+
+        // Create a fifo queue
+
+        Map<String, String> queueAttributes = new HashMap<String, String>();
+        queueAttributes.put("FifoQueue", "true");
+        queueAttributes.put("ContentBasedDeduplication", "true");
+
+        CreateQueueRequest createFifoQueueRequest = new CreateQueueRequest("baeldung-queue.fifo").withAttributes(queueAttributes);
+        String fifoQueueUrl = sqs.createQueue(createFifoQueueRequest)
+            .getQueueUrl();
+
+        System.out.println(fifoQueueUrl);
+
+        // Set up a dead letter queue
+
+        String deadLetterQueueUrl = sqs.createQueue("baeldung-dead-letter-queue")
+            .getQueueUrl();
+
+        GetQueueAttributesResult deadLetterQueueAttributes = sqs.getQueueAttributes(new GetQueueAttributesRequest(deadLetterQueueUrl).withAttributeNames("QueueArn"));
+
+        String deadLetterQueueARN = deadLetterQueueAttributes.getAttributes()
+            .get("QueueArn");
+
+        SetQueueAttributesRequest queueAttributesRequest = new SetQueueAttributesRequest().withQueueUrl(standardQueueUrl)
+            .addAttributesEntry("RedrivePolicy", "{\"maxReceiveCount\":\"2\", " + "\"deadLetterTargetArn\":\"" + deadLetterQueueARN + "\"}");
+
+        sqs.setQueueAttributes(queueAttributesRequest);
+
+        // Send a message to a standard queue
+
+        Map<String, MessageAttributeValue> messageAttributes = new HashMap<>();
+
+        messageAttributes.put("AttributeOne", new MessageAttributeValue().withStringValue("This is an attribute")
+            .withDataType("String"));
+
+        SendMessageRequest sendMessageStandardQueue = new SendMessageRequest().withQueueUrl(standardQueueUrl)
+            .withMessageBody("A simple message.")
+            .withDelaySeconds(30) // Message will arrive in the queue after 30 seconds. We can use this only in standard queues
+            .withMessageAttributes(messageAttributes);
+
+        sqs.sendMessage(sendMessageStandardQueue);
+
+        // Send a message to a fifo queue
+
+        SendMessageRequest sendMessageFifoQueue = new SendMessageRequest().withQueueUrl(fifoQueueUrl)
+            .withMessageBody("FIFO Queue")
+            .withMessageGroupId("baeldung-group-1")
+            .withMessageAttributes(messageAttributes);
+
+        sqs.sendMessage(sendMessageFifoQueue);
+
+        // Send multiple messages
+
+        List<SendMessageBatchRequestEntry> messageEntries = new ArrayList<>();
+        messageEntries.add(new SendMessageBatchRequestEntry().withId("id-1")
+            .withMessageBody("batch-1")
+            .withMessageGroupId("baeldung-group-1"));
+        messageEntries.add(new SendMessageBatchRequestEntry().withId("id-2")
+            .withMessageBody("batch-2")
+            .withMessageGroupId("baeldung-group-1"));
+
+        SendMessageBatchRequest sendMessageBatchRequest = new SendMessageBatchRequest(fifoQueueUrl, messageEntries);
+        sqs.sendMessageBatch(sendMessageBatchRequest);
+
+        // Read a message from a queue
+
+        ReceiveMessageRequest receiveMessageRequest = new ReceiveMessageRequest(fifoQueueUrl).withWaitTimeSeconds(10) // Long polling;
+            .withMaxNumberOfMessages(1); // Max is 10
+
+        List<Message> sqsMessages = sqs.receiveMessage(receiveMessageRequest)
+            .getMessages();
+
+        sqsMessages.get(0)
+            .getAttributes();
+        sqsMessages.get(0)
+            .getBody();
+
+        // Delete a message from a queue
+
+        sqs.deleteMessage(new DeleteMessageRequest().withQueueUrl(fifoQueueUrl)
+            .withReceiptHandle(sqsMessages.get(0)
+                .getReceiptHandle()));
+
+        // Monitoring
+        GetQueueAttributesRequest getQueueAttributesRequest = new GetQueueAttributesRequest(standardQueueUrl).withAttributeNames("All");
+        GetQueueAttributesResult getQueueAttributesResult = sqs.getQueueAttributes(getQueueAttributesRequest);
+        System.out.println(String.format("The number of messages on the queue: %s", getQueueAttributesResult.getAttributes()
+            .get("ApproximateNumberOfMessages")));
+        System.out.println(String.format("The number of messages in flight: %s", getQueueAttributesResult.getAttributes()
+            .get("ApproximateNumberOfMessagesNotVisible")));
+
+    }
+
+}