Java - Socket supportedOptions() Method

Description

The Java Socket supportedOptions() gives a set of the socket options supported by this socket. Even in case of socket being closed, this method returns the set of options.

Declaration

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

public Set<SocketOption<?>> supportedOptions()

Parameters

NA

Return Value

A set of the socket options supported by this socket. This set may be empty if the socket's SocketImpl cannot be created.

Exception

N/A

Example 1

The following example shows the usage of Java Socket supportedOptions() method to get the set of the socket options suppported by this 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. Now we're printing the set of socket options using supportedOptions(). Once done, we're printing the keep alive flag using getKeepAlive() 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("Support Options: "+socket.supportedOptions()); 
      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 −

Support Options: [SO_SNDBUF, SO_RCVBUF, SO_KEEPALIVE, TCP_NODELAY, IP_TOS, SO_LINGER, SO_REUSEADDR]
Port number: 6066
Inet Address: null

Example 2

The following example shows the usage of Java Socket supportedOptions() method to get the set of the socket options suppported by this socket instance. As first step, we've created a Socket instance using no argument constructor. Now, we're printing the keep alive flag using getKeepAlive() method. Then we're setting the keep alive flag as true using setKeepAlive() method and print the same. Now we're printing the set of socket options using supportedOptions(). 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("Is Keep Alive: "+socket.getKeepAlive());
      socket.setKeepAlive(true);  
      System.out.println("Is Keep Alive: "+socket.getKeepAlive());
      System.out.println("Support Options: "+socket.supportedOptions()); 
      socket.close();
   }
}

Output

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

Is Keep Alive: false
Is Keep Alive: true
Support Options: [SO_SNDBUF, SO_RCVBUF, SO_KEEPALIVE, TCP_NODELAY, IP_TOS, SO_LINGER, SO_REUSEADDR]

Example 3

The following example shows the usage of Java Socket supportedOptions() method to get the set of the socket options suppported by this 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 keep alive flag using getKeepAlive() method. Then we're setting the keep alive flag as true using setKeepAlive() method and print the same. In the end, we closed the socket using close() method. Now we're printing the set of socket options using supportedOptions() to see if it still works.

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("Is Keep Alive: "+socket.getKeepAlive());
      socket.setKeepAlive(true);  
      System.out.println("Is Keep Alive: "+socket.getKeepAlive());
      socket.close();
      System.out.println("Support Options: "+socket.supportedOptions()); 
   }
}

Output

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

Is Keep Alive: false
Is Keep Alive: true
Support Options: [SO_REUSEADDR, SO_LINGER, IP_TOS, TCP_NODELAY, SO_KEEPALIVE, SO_RCVBUF, SO_SNDBUF]