Java - Socket getSendBufferSize() Method

Description

The Java Socket getSendBufferSize() returns the value of the SO_SNDBUF option for this Socket, that is the buffer size used by the platform for output on this Socket.

Declaration

Following is the declaration for java.net.Socket.getSendBufferSize() method.

public int getSendBufferSize() throws SocketException

Parameters

NA

Return Value

the value of the SO_SNDBUF option for this Socket.

Exception

SocketException − if there is an error in the underlying protocol, such as a TCP error.

Example 1

The following example shows the usage of Java Socket getSendBufferSize() method to get the value of the SO_SNDBUF option of socket instance. As first step, we've created a Socket instance using no argument constructor. Then in order to create a SocketAddress object, we've initialized an InetAddress instance of localhost address. Using InetSocketAddress object, we've created a SocketAddress object and then using bind() method, we bind the address to the socket. Once done, we're printing the SO_SNDBUF value using getSendBufferSize() method, local port and inetaddress as shown. In the end, we closed the socket using close() method.

package com.tutorialspoint;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;

public class SocketDemo {
   public static void main(String[] args) throws IOException {
      Socket socket = new Socket();  
      InetAddress inetAddress=InetAddress.getByName("localhost");  
      SocketAddress socketAddress=new InetSocketAddress(inetAddress, 6066);  
      socket.bind(socketAddress); 
      
      System.out.println("SO_SNDBUF: "+socket.getSendBufferSize()); 
      System.out.println("Port number: "+socket.getLocalPort()); 
      System.out.println("Inet Address: "+socket.getInetAddress()); 
      socket.close();
   }
}

Output

Let us compile and run the above program, this will produce the following result −

SO_SNDBUF: 8192
Port number: 6066
Inet Address: null

Example 2

The following example shows the usage of Java Socket getSendBufferSize() method to get the value of SO_SNDBUF of socket instance. As first step, we've created a Socket instance using no argument constructor. Now, we're printing the SO_SNDBUF value using getSendBufferSize() method. Then we're setting the SO_SNDBUF value as 1000 using setSendBufferSize() method and print the same. In the end, we closed the socket using close() method.

package com.tutorialspoint;

import java.io.IOException;
import java.net.Socket;

public class SocketDemo {
   public static void main(String[] args) throws IOException {
      Socket socket = new Socket();  

      System.out.println("SO_SNDBUF: "+socket.getSendBufferSize());
      socket.setSendBufferSize(1000);  
      System.out.println("SO_SNDBUF: "+socket.getSendBufferSize());
      socket.close();
   }
}

Output

Let us compile and run the above program, this will produce the following result −

SO_SNDBUF: 8192
SO_SNDBUF: 2304

Example 3

The following example shows the usage of Java Socket getSendBufferSize() method to get the value of SO_SNDBUF of socket instance, if socket is already closed. As first step, we've created a Socket instance using no argument constructor. Using socket.close(), we're closing the socket. Now, we're printing the SO_SNDBUF flag using getSendBufferSize() method. Then we're setting the SO_SNDBUF value as 1000 using setSendBufferSize() method and print the same. In the end, we closed the socket using close() method. As socket is already closed, getSendBufferSize() method call throws an exception as shown below −

package com.tutorialspoint;

import java.io.IOException;
import java.net.Socket;

public class SocketDemo {
   public static void main(String[] args) throws IOException {
      Socket socket = new Socket();  
      socket.close();	  

      System.out.println("SO_SNDBUF: "+socket.getSendBufferSize());
      socket.setSendBufferSize(1000);  
      System.out.println("SO_SNDBUF: "+socket.getSendBufferSize());
      socket.close();
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Exception in thread "main" java.net.SocketException: Socket is closed
	at java.base/java.net.Socket.getSendBufferSize(Socket.java:1232)
	at com.tutorialspoint.SocketDemo.main(SocketDemo.java:11)