Showing posts with label Serialization. Show all posts

Saturday, 4 February 2023

Java Program to Send/Consume Custom Object into/from Kafka Server running on Amazon EC2 Instance

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Kafka on AWS: Sending & Consuming Custom Objects

Moving beyond simple strings is essential for real-world applications. In this tutorial, we "simplify" the process of Sending and Consuming Custom Objects using a Kafka Cluster running on Amazon EC2.

Advanced Producer & Consumer Workflow

We walk through the end-to-end technical setup required to handle complex data types in a cloud environment:

Custom Serialization: Implementing Serializer and Deserializer for your Java objects (e.g., a Student object) using Jackson.
AWS EC2 Setup: Configuring your Kafka server on Amazon EC2 to accept external traffic from your local Java application.
Producer Implementation: Writing the Java code to push complex objects to a specific Kafka topic.
Consumer Implementation: Building the listener that retrieves and reconstructs those objects for processing.

Critical Skills for Cloud Engineers

For Java Developers and DevOps Engineers, integrating local applications with cloud-based messaging is a core requirement. We discuss the configuration details like advertised.listeners and security group settings that are vital for AWS EC2 connectivity. This guide bridges the gap between local development and Enterprise Cloud Architecture.

Practical Clarity for Complex Data

Handling JSON or custom POJOs in Kafka doesn't have to be intimidating. This tutorial provides the code-heavy, practical walkthrough you need to master Object Serialization in a distributed environment. Join us at Ram N Java and take your Apache Kafka expertise to the cloud.

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Java Program to Send Custom Object into Kafka Topic & Consume Custom Object From Kafka Topic

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Kafka Java: Sending & Consuming Custom POJOs

While strings are simple, real-world enterprise applications deal with complex data. In this tutorial, we "simplify" the process of Sending and Consuming Custom Objects (POJOs) using Apache Kafka and Java.

Handling Complex Data Types

We walk through the complete implementation for moving structured data through your Kafka cluster:

Custom Serializer: Implementing the Serializer interface to convert Java objects into byte arrays using Jackson.
Custom Deserializer: Implementing the Deserializer interface to reconstruct your objects on the consumer side.
Producer Configuration: Setting up the KafkaProducer to use your custom class for value serialization.
Consumer Implementation: Building the polling loop that receives and casts data back to your custom Java class.

Essential for Microservices

For Java Developers, the ability to send domain objects like User, Order, or Product directly through Kafka is a fundamental skill. We show you how to leverage the Jackson ObjectMapper to handle JSON conversion seamlessly, ensuring your Event-Driven Architecture is robust and type-safe. This guide provides the practical code you need for real-world development.

Practical Code-First Learning

Don't get stuck with just text messages. This tutorial provides the technical clarity to handle any data structure in Apache Kafka. By walking through a concrete example with a "Student" object, we make complex serialization accessible. Join us at Ram N Java and elevate your backend programming skills.

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Wednesday, 30 November 2022

Spring Boot with Spring Kafka Producer Example | Apache Kafka Publisher Example using SpringBoot

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Spring Boot & Kafka: A Deep Dive into Producer Logic

Efficiently sending data to a distributed log is the first step in any streaming pipeline. In this tutorial, we "simplify" the Spring Boot Kafka Producer, taking you from initial setup to a production-ready implementation.

Inside the Producer Pipeline

We explore the technical building blocks required to publish reliable messages within the Spring ecosystem:

KafkaTemplate Architecture: Deep diving into how Spring's KafkaTemplate simplifies message delivery and handles synchronization under the hood.
Serialization Strategies: Configuring key and value serializers to ensure your data is correctly formatted for the Kafka broker.
Advanced Configuration: Fine-tuning application.properties for bootstrap servers, acknowledgments (acks), and retries.
Producer Factory Setup: Understanding the role of ProducerFactory in managing the lifecycle of your Kafka producers.

Mastering Event-Driven Design

For Java Developers, mastering the producer side is critical for building high-throughput Event-Driven Architectures. We show you how Spring Boot removes the complexity of the native Kafka API, allowing you to focus on your application's core business logic. This guide provides the conceptual and technical clarity needed to scale your Microservices effectively.

Practical Implementation & Results

Watch as we build a complete producer from scratch and demonstrate real-time message publishing to a local Kafka cluster. This deep dive gives you a robust template that you can confidently deploy in a professional environment. Join us at Ram N Java and take your Spring Boot and Kafka skills to the next level.

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Tuesday, 4 October 2022

Apache Kafka - Create a Simple Producer in Java | Java Kafka Producer code | Java with Apache Kafka

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Java Kafka Producer: A Step-by-Step Implementation Guide

Publishing data to a distributed stream is a fundamental skill for any modern developer. In this tutorial, we "simplify" the creation of an Apache Kafka Producer in Java, walking you through the exact four steps needed to start sending messages to a Kafka topic.

The 4 Essential Steps to Produce Messages

We break down the technical workflow required to build a functioning producer from scratch:

Step 1: Producer Properties: Setting up the Properties object with vital configurations like bootstrap.servers, key.serializer, and value.serializer.
Step 2: Create Producer: Initializing the KafkaProducer object by passing your custom properties.
Step 3: Create Producer Record: Defining the ProducerRecord which specifies the destination topic and the message data.
Step 4: Send Data: Using the send() method to dispatch your record asynchronously to the Kafka cluster.

Critical Logic: Flush and Close

For Java Developers, understanding the asynchronous nature of Kafka is key. We explain why calling flush() and close() in a finally block is mandatory. Without these, the main thread may exit before the data is actually pushed from the internal buffer to the server. This guide provides the conceptual clarity to ensure Data Integrity in your Microservices.

Live Demo & CLI Integration

Watch the complete end-to-end flow: from starting Zookeeper and Kafka servers to creating a multi-partition topic via CLI, and finally running our Java program. We even show a live consumer catching the messages in real-time! Join us at Ram N Java and elevate your Apache Kafka expertise today.

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Friday, 23 April 2021

Returning Java Object as Return Value - RESTful Web Services with Spring framework | Spring Boot

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Returning Java Objects in REST APIs

In this tutorial, we explore the core of RESTful Web Services: returning Java objects as JSON responses. We demonstrate how Spring Boot seamlessly handles data serialization, making it incredibly easy to build data-driven applications.

The Magic of Serialization

Spring Boot uses the Jackson library under the hood to convert your Java POJOs into JSON. We walk through the process of creating a clean data model and exposing it through a controller:

@RestController: Understanding how this annotation combines @Controller and @ResponseBody to simplify your API development.
POJO Design: Best practices for creating simple Java objects that map perfectly to your API responses.
Automatic Conversion: See how Spring automatically sets the correct Content-Type to application/json.

Live Practical Session

We build a simple Employee model and a corresponding EmployeeController from scratch. You'll see exactly how to return single objects and lists of objects, and how they appear when requested via a web browser or Postman.

Why Master This?

Mastering how to return objects is the first step in building any real-world backend. It's the foundation for microservices, mobile app backends, and modern web applications. By understanding these Spring Boot fundamentals, you're well on your way to becoming a professional Java developer.

📥 Get the Source Code!

I have shared the full Java source code for this tutorial! Check out the download links in the YouTube video description above to get started with the code.

Monday, 10 June 2019

How to Send/Receive Product object to/from Queue using Java program? | RabbitMQ tutorial

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Sending Java Objects to RabbitMQ

Modern applications need to exchange complex data structures, not just simple text. In this tutorial, we "simplify" the process of sending and receiving custom Java Objects through RabbitMQ queues using the Java client library.

Object Serialization Simplified

To send an object over the wire, it must first be converted into a format RabbitMQ understands. We walk you through the core concepts of object handling in a messaging environment:

Defining Your POJO: Creating a simple, serializable Java class to represent your data (like an Employee or Order).
Serialization: Using Java's built-in serialization or libraries like Jackson to convert objects into byte arrays for transmission.
Deserialization: How the consumer reconstructs the original Java object from the received message bytes.

The Producer and Consumer Logic

We demonstrate a complete working example of a Producer sending a Java object and a Consumer waiting to receive it. You'll learn how to manage connections, channels, and queues while ensuring that your data remains intact throughout the entire messaging lifecycle. This hands-on approach shows you the "under-the-hood" mechanics of Java messaging.

A Vital Skill for Java Developers

Mastering Object Messaging with RabbitMQ is essential for building decoupled and distributed Java applications. It allows different parts of your system to share complex state without being directly linked. Whether you're working on microservices or legacy system integration, this skill is a cornerstone of professional Backend Development.

📥 Download the Source Code!

The complete Java source code and PowerPoint presentation for this object messaging tutorial are available! Check the download links in the YouTube video description above to get started.

Tuesday, 4 October 2016

Java Tutorial : Java IO (Java Serialization with HAS A Inheritance)

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Understanding Java Serialization with HAS-A Relationship

In the world of Java programming, **Serialization** is the process of converting an object's state into a byte stream. This is crucial when you want to save an object to a file or send it over a network. But what happens when your class contains another class (a HAS-A relationship)? Let's break it down in a beginner-friendly way.

The Core Concept: Object Graphs

When you serialize an object, Java doesn't just look at the top-level class. It looks at the entire "object graph." If your class has a reference to another object (HAS-A), Java will attempt to serialize that referenced object as well.

The Golden Rule

For serialization to work smoothly in a HAS-A relationship, every object in the graph must be Serializable. If your main class implements the java.io.Serializable interface, but the class it "has" does not, Java will throw a NotSerializableException at runtime.

How to Handle Non-Serializable Members

Sometimes, you might have a member object that cannot be serialized (like a database connection or a file stream). In these cases, you have two main options:

Implement Serializable: Make the referenced class implement the Serializable interface.
Use the 'transient' Keyword: If you don't want or can't serialize a specific member, mark it as transient. Java will skip this field during the serialization process, and it will be initialized with its default value (like null for objects) during deserialization.

Key Takeaways for Beginners

Serialization is recursive; it tries to save everything the object "owns."
Always ensure nested objects are Serializable.
Use transient to protect sensitive data or skip non-serializable components.

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Java Tutorial : Java IO (Java Serialization with HAS A Inheritance)

Address.java

import java.io.Serializable;

public class Address implements Serializable
{
    private static final long serialVersionUID = 8899023823185198093L;
    private String streetName;
    private String city;
    private String state;

    public Address(String streetName, String city, String state)
    {
        super();
        this.streetName = streetName;
        this.city = city;
        this.state = state;
    }

    public String getStreetName()
    {
        return streetName;
    }

    public void setStreetName(String streetName)
    {
        this.streetName = streetName;
    }

    public String getCity()
    {
        return city;
    }

    public void setCity(String city)
    {
        this.city = city;
    }

    public String getState()
    {
        return state;
    }

    public void setState(String state)
    {
        this.state = state;
    }

    @Override
    public String toString()
    {
        return "Address [streetName=" + streetName + ", city=" + city
                + ", state=" + state + "]";
    }

}

Employee.java

import java.io.Serializable;

/*
 * If a class has a reference of another class, all the
 * references must be Serializable otherwise
 * serialization process will not be performed. In such
 * case, NotSerializableException is thrown at runtime.
 * 
 * If Address is not Serializable, we cannot serialize
 * the instance of Employee class.
 */
public class Employee implements Serializable
{

    private static final long serialVersionUID = 765764534241652904L;
    private int id;
    private String name;
    private Address address; // HAS-A

    public Employee(int id, String name, Address address)
    {
        super();
        this.id = id;
        this.name = name;
        this.address = address;
    }

    public int getId()
    {
        return id;
    }

    public void setId(int id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    public Address getAddress()
    {
        return address;
    }

    public void setAddress(Address address)
    {
        this.address = address;
    }

}

SerializationDemo.java

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;

public class SerializationDemo
{

    public static void main(String[] args) throws FileNotFoundException,
            IOException, ClassNotFoundException
    {
        SerializationDemo serializationDemo = new SerializationDemo();
        serializationDemo.writeEmployeeObject();
    }

    private void writeEmployeeObject() throws FileNotFoundException,
            IOException
    {
        FileOutputStream fileOutputStream = null;
        ObjectOutputStream objectOutputStream = null;
        try
        {
            fileOutputStream = new FileOutputStream("employee.tmp");
            objectOutputStream = new ObjectOutputStream(fileOutputStream);

            Address address = new Address("North Street", "Chennai",
                                                            "Tamil Nadu");

            Employee employee = new Employee(101, "Peter", address);

            /*
             * Write the specified object to the
             * ObjectOutputStream.
             */
            objectOutputStream.writeObject(employee);
            System.out
                    .println("Successfully written employee object to the file.\n");
        }
        finally
        {

            if (objectOutputStream != null)
            {
                /*
                 * Closing a ObjectOutputStream will also
                 * close the OutputStream instance to which
                 * the ObjectOutputStream is writing.
                 */
                objectOutputStream.close();
            }
        }

    }

}

Output

Successfully written employee object to the file.

employee.tmp

DeSerializationDemo.java

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.ObjectInputStream;

public class DeSerializationDemo
{

    public static void main(String[] args) throws FileNotFoundException,
            IOException, ClassNotFoundException
    {
        DeSerializationDemo deSerializationDemo = new DeSerializationDemo();
        deSerializationDemo.readEmployeeObject();
    }

    private void readEmployeeObject() throws IOException,
            FileNotFoundException, ClassNotFoundException
    {
        FileInputStream fileInputStream = null;
        ObjectInputStream objectInputStream = null;

        try
        {
            fileInputStream = new FileInputStream("employee.tmp");
            objectInputStream = new ObjectInputStream(fileInputStream);

            /*
             * Read an object from the ObjectInputStream.
             */
            Employee employee = (Employee) objectInputStream.readObject();

            System.out
                    .println("Successfully read employee object from the file.");

            System.out.println("Id  = " + employee.getId());
            System.out.println("Name = " + employee.getName());
            Address address = employee.getAddress();
            System.out.println("Address  = " + address);
        }
        finally
        {

            if (objectInputStream != null)
            {
                /*
                 * Closing a ObjectInputStream will also
                 * close the InputStream instance from which
                 * the ObjectInputStream is reading.
                 */
                objectInputStream.close();
            }
        }

    }

}

Output

Successfully read employee object from the file.
Id  = 101
Name = Peter
Address  = Address [streetName=North Street, city=Chennai, state=Tamil Nadu]

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/JavaIODemo_Serialization_HAS_A_Relationship_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/JavaIODemo_Serialization_HAS_A_Relationship_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/9ef303db3f229fc70e7cf47baac5692282611e62/BasicJava/JavaIODemo_Serialization_HAS_A_Relationship_App/?at=master

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Servlets Tutorial

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JDBC Tutorial

Java Collection Framework Tutorial

JAVA Tutorial

Kids Tutorial

Monday, 3 October 2016

Java Tutorial : Java IO (Java Serialization with IS A Inheritance)

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Java Serialization with IS-A (Inheritance)

Welcome back! Today, we are diving deep into how Serialization works when Inheritance (IS-A relationship) is involved. This is a common topic in interviews and a must-know for any Java developer working with object persistence.

What is the IS-A Relationship in Serialization?

In Java, when a child class inherits from a parent class, it is known as an IS-A relationship. When it comes to Serialization, the main question is: If a parent class is serializable, is the child class also serializable? Let’s look at the different scenarios.

Scenario 1: Parent Class Implements Serializable

If a Parent class implements the java.io.Serializable interface, then every Child class that extends it automatically becomes serializable. You don't need to explicitly implement the interface in the child class. This is because the serializable property is inherited.

Scenario 2: Parent is NOT Serializable, but Child IS

This is a tricky part! If the Parent class does not implement Serializable, but the Child class does, you can still serialize the Child object. However, there are specific rules:

During deserialization, Java will run the default constructor of the non-serializable Parent class.
Any fields inherited from the non-serializable Parent will be reset to their default values (e.g., 0 for int, null for objects).
Important: The Parent class must have a no-argument constructor; otherwise, a InvalidClassException will be thrown.

Key Takeaways for Beginners

Inheritance Matters: If the base class is serializable, all subclasses are too.
Constructor Rule: Always check if your non-serializable parent classes have a default constructor if you plan to serialize the children.
Data Loss: Be careful with non-serializable parents, as their specific state won't be saved during the process.

Watch More from Ram N Java:

Keep learning with these related Java IO tutorials:

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Java Tutorial : Java IO (Java Serialization with IS A Inheritance)

Person.java

import java.io.Serializable;

/*
 * If a class implements serializable then all its sub
 * classes will also be serializable.
 */
public class Person implements Serializable
{

    private static final long serialVersionUID = -7438582605700356851L;
    protected String name;
    protected int age;

    public Person(String name, int age)
    {
        super();
        this.name = name;
        this.age = 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;
    }

}

Employee.java

/*
 * We can serialize the Employee class object that
 * extends the Person class which is Serializable.Parent
 * class properties are inherited to subclasses so if
 * parent class is Serializable, subclass would also be.
 */
public class Employee extends Person
{

    private static final long serialVersionUID = 312396230370712755L;
    private int salary;

    public Employee(String name, int age, int salary)
    {
        super(name, age);
        this.salary = salary;
    }

    public int getSalary()
    {
        return salary;
    }

    public void setSalary(int salary)
    {
        this.salary = salary;
    }

}

SerializationDemo.java

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;

public class SerializationDemo
{

    public static void main(String[] args) throws FileNotFoundException,
            IOException, ClassNotFoundException
    {
        SerializationDemo serializationDemo = new SerializationDemo();
        serializationDemo.writeEmployeeObject();
    }

    private void writeEmployeeObject() throws FileNotFoundException,
            IOException
    {
        FileOutputStream fileOutputStream = null;
        ObjectOutputStream objectOutputStream = null;
        try
        {
            fileOutputStream = new FileOutputStream("employee.tmp");
            objectOutputStream = new ObjectOutputStream(fileOutputStream);

            Employee employee = new Employee("Peter", 29, 80000);

            /*
             * Write the specified object to the
             * ObjectOutputStream.
             */
            objectOutputStream.writeObject(employee);
            System.out
                    .println("Successfully written employee object to the file.\n");
        }
        finally
        {

            if (objectOutputStream != null)
            {
                /*
                 * Closing a ObjectOutputStream will also
                 * close the OutputStream instance to which
                 * the ObjectOutputStream is writing.
                 */
                objectOutputStream.close();
            }
        }

    }

}

Output

Successfully written employee object to the file.

employee.tmp

DeSerializationDemo.java

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.ObjectInputStream;

public class DeSerializationDemo
{

    public static void main(String[] args) throws FileNotFoundException,
            IOException, ClassNotFoundException
    {
        DeSerializationDemo deSerializationDemo = new DeSerializationDemo();
        deSerializationDemo.readEmployeeObject();
    }

    private void readEmployeeObject() throws IOException,
            FileNotFoundException, ClassNotFoundException
    {
        FileInputStream fileInputStream = null;
        ObjectInputStream objectInputStream = null;

        try
        {
            fileInputStream = new FileInputStream("employee.tmp");
            objectInputStream = new ObjectInputStream(fileInputStream);

            /*
             * Read an object from the ObjectInputStream.
             */
            Employee employee = (Employee) objectInputStream.readObject();

            System.out
                    .println("Successfully read employee object from the file.");

            System.out.println("Name = " + employee.getName());
            System.out.println("Age  = " + employee.getAge());
            System.out.println("Salary  = " + employee.getSalary());
        }
        finally
        {

            if (objectInputStream != null)
            {
                /*
                 * Closing a ObjectInputStream will also
                 * close the InputStream instance from which
                 * the ObjectInputStream is reading.
                 */
                objectInputStream.close();
            }
        }

    }

}

Output

Successfully read employee object from the file.
Name = Peter
Age  = 29
Salary  = 80000

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/JavaIODemo_Serialization_IS_A_Relationship_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/JavaIODemo_Serialization_IS_A_Relationship_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/9ef303db3f229fc70e7cf47baac5692282611e62/BasicJava/JavaIODemo_Serialization_IS_A_Relationship_App/?at=master

See also:

All JavaEE Viedos Playlist

All JavaEE Viedos

All JAVA EE Links

Servlets Tutorial

All Design Patterns Links

JDBC Tutorial

Java Collection Framework Tutorial

JAVA Tutorial

Kids Tutorial