Java - Socket setSoLinger() Method

Description

The Java Socket setSoLinger(boolean on, int linger) enables/disables SO_LINGER value with the given linger time in seconds. The maximum timeout value is platform specific. The setting only affects socket close.

Declaration

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

public void setSoLinger(boolean on, int linger) throws SocketException

Parameters

on − whether or not to linger on.

linger − how long to linger for, if on is true.

Return Value

N/A

Exception

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

IllegalArgumentException − if the linger value is negative.

Example 1

The following example shows the usage of Java Socket setSoLinger() method to set the value of the SO_LINGER 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. Then we're disabling the SO_LINGER value using setSoLinger() method. Once done, we're printing the SO_LINGER value using getSoLinger() 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); 
      socket.setSoLinger(false, 1); 
      System.out.println("SO_LINGER: "+socket.getSoLinger()); 
      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_LINGER: -1
Port number: 6066
Inet Address: null

Example 2

The following example shows the usage of Java Socket setSoLinger() method to set the value of SO_LINGER of socket instance. As first step, we've created a Socket instance using no argument constructor. Now, we're printing the SO_LINGER value using getSoLinger() method. Then we're setting the SO_LINGER value as 1 using setSoLinger() 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_LINGER: "+socket.getSoLinger());
      socket.setSoLinger(true, 1);  
      System.out.println("SO_LINGER: "+socket.getSoLinger());
      socket.close();
   }
}

Output

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

SO_LINGER: -1
SO_LINGER: 1

Example 3

The following example shows the usage of Java Socket setSoLinger() method to set the value of SO_LINGER 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_LINGER flag using getSoLinger() method. Then we're setting the SO_LINGER value as 1000 using setSoLinger() method and print the same. In the end, we closed the socket using close() method. As socket is already closed, getSoLinger() 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_LINGER: "+socket.getSoLinger());
      socket.setSoLinger(false, 1);  
      System.out.println("SO_LINGER: "+socket.getSoLinger());
      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.getSoLinger(Socket.java:1061)
	at com.tutorialspoint.SocketDemo.main(SocketDemo.java:11)