Java - Socket isClosed() Method

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Description

The Java Socket isClosed() returns the closed state of the socket.

Declaration

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

public boolean isClosed()

Parameters

NA

Return Value

true if the socket was closed.

Exception

NA

Example 1

The following example shows the usage of Java Socket isClosed() method to get the closed status 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 closed state using isClosed() method, local port and inetaddress as shown. In the end, we closed the socket using close() method. Then again, we're printing the closed state using isClosed() 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("Is closed: "+socket.isClosed()); 
      System.out.println("Port number: "+socket.getLocalPort()); 
      System.out.println("Inet Address: "+socket.getInetAddress()); 
      socket.close();
      System.out.println("Is closed: "+socket.isClosed()); 
   }
}

Output

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

Is closed: false
Port number: 6066
Inet Address: null
Is closed: true

Example 2

The following example shows the usage of Java Socket isClosed() method to get the closed status of socket instance. As first step, we've created a Socket instance using no argument constructor. Now we're printing the closed state using isClosed() method. In the end, we closed the socket using close() method. Once done, we're again printing the closed state using isClosed() method as shown −

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 closed: "+socket.isClosed());
      socket.close();
      System.out.println("Is closed: "+socket.isClosed());
   }
}

Output

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

Is closed: false
Is closed: true

java-socket.htm