Do you want to try Java Networking to build client-server applications? We can help you understand it easily so you don’t face any hiccups in your programming journey.
Java is a powerful language that can be used for multiple purposes. From game development to web applications, you can leverage it to build scalable software or apps. It also provides us with networking capabilities to create client-server applications.
In this article, we will cover the basics of how to create applications based on the client-server architecture using Java. Ready to dive in?
Summary Of The Article:
- Java programming language provides us with packages and networking features.
- We can use the Socket class and its methods to create a client-server application.
- It is important to follow security considerations and write code that is performance-efficient.
An Overview Of Java Networking Basics
A system of interconnected computer resources forms a network. Java offers us various packages to establish a network between these resources so that they can communicate with each other over the internet.
We can write Java programs that can execute over different devices in the network to perform some operations. The programs for Java Networking are written in the application layer of the TCP/IP networking model.
With the help of Java, we can create robust, scalable, and performance-efficient client-server applications. Since many real-world applications require concurrent processing, learning about Multithreading in Java will help you write more efficient networking code.
In this programming language, we have packages like java.net and java.nio for handling communication APIs, and sockets. Let’s look at the components associated with Java networking.
Java Networking Components That You Should Remember
Below are the terminologies and components that we use for networking in Java. Let us go through them one at a time.
1. Networking Protocols
In Java networking, we mainly use two networking protocols to establish connections between two or more resources in the network. These are –
- TCP: TCP stands for Transmission Control Protocol. It is a reliable protocol that helps us to establish connections between resources. It allows us to send and receive data by first creating a connection between the two devices.
- UDP: UDP stands for User Datagram Protocol. It is a connection-less protocol that allows us to transmit data packets between different applications.
2. Web Sockets
Web sockets are the endpoints for a communication channel. These help us to establish real-time communication between two applications. Each socket has its associated port number so that the TCP layer can identify the application for sending or receiving data.
For TCP/IP communication, the sockets have a port number destined for them. Managing data efficiently across a network often involves database operations—learn how to Concatenate Two Columns In SQL to improve your database handling skills.
Client-server communication can be established with the help of sockets and socket programming using Java. In the following sections of this article, we will see the implementation of web sockets in client-server apps.
3. Ports
Ports are the receivers of the data. Any data that is arriving from other resources is received by these. Normally, a computer has only 1 physical connection through which it gets the data. However, if you are using multiple applications and need data for all those, using that single port is not an option.
For applications connected over the internet, we use Ports. These ports have port numbers associated with them. Data transmitted over the internet has information about the address where it will be received and the port number where it will go.
Let us implement a simple TCP communication-based client-server network using socket programming in Java. Have a look below!
Implementation Of A Simple Client-Server Application In Java
Let us first write the code for creating the server in Java. For this, we are going to use socket programming. The port number that we have selected is 8080. The Java program for the same is given below.
Server Program
// import the necessary packages for establishing the network
import java.net.*;
import java.io.*;
// create the server
public class Server {
public static void main(String[] args) throws IOException{
// create the Server Socket
// we are using port number 8080
int port = 8080;
ServerSocket serverSocket = new ServerSocket(port);
System.out.println("Server is listening on port " + port);
// the server is waiting for the client connection
while(true){
// we will accept the client connection
Socket socket = serverSocket.accept();
System.out.println("Client connection successful");
// reading data transmitted by the client
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
String clientMessage = in.readLine();
System.out.println("Received message is: " + clientMessage);
// send response to client
out.println("Hello from server! You said: " + clientMessage);
// close client socket
socket.close();
// close server socket
serverSocket.close();
}
}
}
Explanation Of The Program:
- First, we have imported the packages for input/output operations and networking.
- We have created a Server class and created a new serverSocket using the serverSocket() class that listens on port number 8080.
- When the connection is accepted by the server, we are able to read the data using BufferReader and send back a response to the client.
- It is important to close the client and server sockets at the end of the program.
Let’s see the output of the server code when it is not connected to the client.
Server Output Without Connection:
Now that we have created our server, let us also similarly create a client. The client will use localhost 8080 as the address of the server. The code is given below.
Client Program
// import the necessary packages for establishing the network
import java.net.*;
import java.io.*;
// create the client
public class Client{
public static void main(String[] args) throws IOException{
// create a client socket on port 8080
int port = 8080;
Socket socket = new Socket("localhost", port);
// send message to server
PrintWriter output = new PrintWriter(socket.getOutputStream(), true);
output.println("Hello Server!");
// read response from server
BufferedReader input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String response = input.readLine();
System.out.println("Server says: " + response);
// close socket
socket.close();
}
}
Explanation Of The Program:
- We have imported the Java packages for I/O operations and networking.
- The Client class is created and inside it, with the help of the socket class and providing it with the server address and the port number.
- We are also sending a message to the server and storing it in the output variable.
- The response from the server will be displayed in the client’s terminal.
Below are the outputs of the server’s terminal after the connection is accepted as well as the client’s terminal that shows the response.
Still stuck? Ask our experts to step in if you’re struggling with your Java networking project.
Server Output With Connection:
Why Do We Need To Build Efficient And Secure Client-Server Applications?
We are living in an era where almost every daily process happens with the help of the internet. Billions of users interact with each other through digital communication channels. From e-commerce websites to chat applications, multiplayer games, and more, client-server architecture is the backbone for seamless data exchange.
Therefore, it is important to have a secure and robust platform for sharing data. Let us see some of the reasons that highlight the importance of building efficient and secure client-server applications. Have a look below!
- For enhancing performance and scalability: With millions of users browsing the internet, it becomes a challenge to provide a good user experience for the audience. Building an efficient application that can handle a high amount of requests and address the latency issues is therefore necessary.
- Reducing server load: While designing your application, it is highly vital to handle unnecessary resource consumption that can lead to increased server costs and potential downtime. Load balancing and connection pooling help to distribute traffic and also reuse existing connections respectively.
- For Ensuring Data Integrity: Another reason why you should create secure and efficient apps is to make sure that your application deals with vulnerabilities and security threats that lead to data leaks and cyberattacks. Encryption techniques and MFA helps to design better systems.
What Are The Advanced Networking Techniques in Java?
Once you have understood how to create a simple client-server architecture in Java using socket programming, you are ready to move to the next phase and learn about the advanced networking techniques that are used to make the system more efficient and suitable for larger applications.
Let us get to know about these methods one by one. Have a look below to understand.
Non-blocking I/O with NIO
Usually, in socket programming, each client connection has its separate thread. Having a lot of threads can lead to a bottleneck situation when the server is receiving multiple connection requests.
In this case, socket programming relies on blocking I/O. However, Java offers New I/O operations that are suitable in case of multiple connections and make the application more scalable by supporting non-blocking communication.
Selector selector = Selector.open();
ServerSocketChannel serverSocket = ServerSocketChannel.open();
serverSocket.configureBlocking(false);
Here, you make use of channels and buffers instead of input and output data streams. You can also make use of selectors to handle multiple connections with the help of a single thread.
Since it uses non-blocking communication, the system makes sure that execution is not blocked. Using this technique adds efficiency to your application.
Asynchronous Channels
If you are creating a large-scale application, using asynchronous communication in Java is a great way to handle a large number of client requests. Asynchronous programming is a technique that allows us to perform multiple actions without waiting for the previous ones to finish.
It makes use of callback and future objects for non-blocking communication. By following this technique you can enhance your CPU efficiency and perform real-time operations with ease.
Asynchronous channels are used in event-driven models and are ideal for applications that use highly concurrent operations with minimal overload. The syntax to declare an asynchronous socket is given below.
AsynchronousServerSocketChannel server = AsynchronousServerSocketChannel.open()
.bind(new InetSocketAddress(8080));
Resource Management For Performance Optimization
As we discussed above, an efficient client-server application includes resource management that ultimately leads to better performance. Properly managed resources prevent issues such as memory leaks, socket exhaustion, and performance degradation.
In the above programs, you may have noticed the socket.close() function. It is a best practice that you should follow to close the resources or free memory after their use. For safe socket management and latency optimization, you can also use the try with resources block in Java.
Real-World Applications Of Java Networking
It is time to look at some of the real-world scenarios where Java networking is used for client-server applications. You can also create such applications with the help of socket programming in Java.
Real-Time Chat Application
: Java is one of the popular languages that is used to create high-end chat applications. With concepts like asynchronous programming, web sockets, and message queues, we can develop a functional app. For latency optimization, it is recommended to use NIO sockets.
For example, if you want to implement a chat app similar to Slack or WhatsApp using Java, you must make sure to cover the key areas like end-to-end encryption and maintaining a persistent connection.
File Transfer System:
A file transfer system is another example where networking is used to establish client-server communication. A reliable file transfer system can be developed using asynchronous NIO that handles multiple chunks of file. Ensure that error handling and logging are done to monitor or catch any errors.
Data corruption is an issue that you may face as a beginner if you are creating a file transfer system. This usually occurs when there is a networking issue that leads to loss of data. You can create a checkpoint system that allows resumable downloads for the same.
Ticket booking System
: Online ticket booking systems also make use of the client-server architecture using Java. These are large-scale applications that handle multiple requests. Hence, it is important to remember all the performance considerations while developing the software so that booking and billing are done seamlessly.
Whenever finances are involved, you need to make sure that the security is top-notch. TLS encryption and hashing algorithms are your guide when creating such systems to ensure data protection and data integrity.
Real-time chat Applications are a great way to implement networking in Java. If you’re preparing for Java-related job interviews, our Top Java Interview Questions and Answers can help you tackle questions on Java networking.
Conclusion
I hope that by now you have understood the Java networking basics and can start to implement a simple client-server application on your own. Remember to keep in mind the performance considerations and best practices that we have listed for you.
Once you get the hang of the simple app, you can try using the advanced Java features to develop large-scale applications like an e-commerce platform or a billing system. If you feel stuck or need help with Java, you can reach out to our team.
Happy coding!
Takeaways:
- In Java, you can make use of TCP/IP communication or UDP communication to establish a client-server architecture.
- New and advanced Java features like Non-blocking I/O and asynchronous channels will help you to create an efficient system.
- It is important to perform testing and integrate security features like firewall considerations and network security to protect your data and app from cyber threats.
