Java Authenticator setDefault() Method

Last Updated : 17 Mar 2025

The setDefault() method of Authenticator class sets the authenticator that is used by the networking code when a proxy or an HTTP server asks for authentication.

Syntax:

Parameter:

a - The authenticator to be set. If a is null, then any previously set authenticator is removed.

Return:

The InetAddress of the site requesting for authorization, or null if it is not available.

Throw:

SecurityException

Example 1

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.net.Authenticator; 
import java.net.InetAddress; 
import java.net.MalformedURLException; 
import java.net.PasswordAuthentication; 
import java.net.URL; 
  
public class AuthenticatorgetsetDefaultExample1 
{ 
    public static void main(String[] args)  
    { 
        try { 
            ClassAuthenticator obj1 =new ClassAuthenticator();
            Authenticator.setDefault(new ClassAuthenticator()); 
            URL url = new URL("https://www.tpointtech.com");     
            BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream())); 
            String line; 
            System.out.println("Port info ::"+url.getPort()); 
           obj1.getPasswordAuthentication() ;
           
            while ((line = in.readLine()) != null) { 
                System.out.println(line); 
            } 
            in.close(); 
        } catch (MalformedURLException e) { 
            System.out.println("Malformed URL: " + e.getMessage()); 
        } catch (IOException e) { 
           System.out.println("I/O Error: " + e.getMessage()); 
        } 
    } 
  
    public static class ClassAuthenticator extends Authenticator  
    { 
        protected PasswordAuthentication getPasswordAuthentication()  
        { 
            this.show();
            String username = "TpointTech"; 
            String password = "java"; 
            return new PasswordAuthentication(username, password.toCharArray()); 
        } 
        void show()
        {
            System.out.println("URL :" +getRequestingURL());  
        }
    } 
} 

Output:

Port info ::-1
URL :null
// source code of https://www.tpointtech.com is printed.

Example 2

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.net.Authenticator; 
import java.net.InetAddress; 
import java.net.MalformedURLException; 
import java.net.PasswordAuthentication; 
import java.net.URL; 
  
public class AuthenticatorgetsetDefaultExample2   
{ 
    public static void main(String[] args)  
    {   
        try { 
             ClassAuthenticator obj1 =new ClassAuthenticator();
            Authenticator.setDefault(new ClassAuthenticator()); 
            obj1.getPasswordAuthentication() ;
            URL url = new URL("https://www.tpointtech.com"); 
            BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream())); 
            System.out.println("Protocol:" + url.getProtocol());  
            String line; 
            while ((line = in.readLine()) != null) { 
                System.out.println(line); 
            } 
            in.close(); 
        } catch (MalformedURLException e) { 
            System.out.println("Malformed URL: " + e.getMessage()); 
        } catch (IOException e) { 
            System.out.println("I/O Error: " + e.getMessage()); 
        } 
    } 
  
    public static class ClassAuthenticator extends Authenticator  
    { 
        protected PasswordAuthentication getPasswordAuthentication()  
        { 
            System.out.println("URL info :" +getRequestingURL()); 
            String username = "TpointTech"; 
            String password = "java"; 
            return new PasswordAuthentication(username, password.toCharArray()); 
        } 
    } 
} 

Output:

URL info :null
Protocol:https
// source code of https://www.tpointtech.com is printed.

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Java Authenticator setDefault() Method

Syntax:

Parameter:

Return:

Throw:

Example 1

Example 2

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