Difference between Applets and Servlets in Java.

In java, both Applets and servlets are the programs or applications that run in a java environment. The main difference in both the programs is in their processing is done in different environments.

The following are the important differences between Applets and Servlets.

Sr. No.	Key	Applets	Servlets
1	Execution	Applets are executed on client-side i.e applet runs within a Web browser on the client machine.	Servlets on other hand executed on the server-side i.e servlet runs on the web Page on server.
2	Parent packages	Parent package of Applet includes java.applet.* and java.awt.*	Parent package of Servlet includes javax.servlet.* and java.servlet.http.*
3	Methods	Important methods of applet includes init(), stop(), paint(), start(), destroy().	Lifecycle methods of servlet are init( ), service( ), and destroy( ).
4	User interface	For the execution of the applet, a user interface is required such as AWT or swing.	No such interface is required for the execution of servlet.
5	Required Bandwidth	The applet requires user interface on the client machine for execution so it requires more bandwidth.	On the other hand, Servlets are executed on the servers and hence require less bandwidth.
6	Secure	Applets are more prone to risk as execution is on the client machine.	Servlets are more secure as execution is under server security.

Example of applet vs servlet

AppletDemo.java

import java.applet.Applet;
import java.awt.Graphics;
public class AppletDemo extends Applet {
   // Overriding paint() method
   @Override
   public void paint(Graphics g){
      g.drawString("AppletDemo", 20, 20);
   }
}

Output

AppletDemo

Example

ServletDemo.java

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ServletDemo extends HttpServlet {
   private String message;
   public void init() throws ServletException{
      // Do required initialization
      message = "Servlet Demo";
   }
   public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
      out.println(message);
   }
}

Output

Servlet Demo