Servlet vs JSP

Servlet is java code and it is used to create dynamic web pages, which deployed in server (e.g tomcat, jboss).
see below simple servlet example -

import java.io.*;

import javax.servlet.http.*;
import javax.servlet.*;

public class MyServlet extends HttpServlet { 

  public void doGet (HttpServletRequest 

                       req,HttpServletResponse res)
    throws ServletException, IOException
  {
    PrintWriter out = res.getWriter();

    out.println("Basic servlet example");
    out.close();
  }
}

Here we have created MyServlet class which extends HttpServlet. we

have overrided here doGet method which will invoked by GET method 

of http request.

Servlet class before putting to the server,need to compile it 

manually. To know more about servlet click here 

JSP a scripting language and it is used to create web pages, which 

deployed in server. It is easy to understand.This is different than 

other scripting language.

JSP class before putting to server, no need to compile it. Because 

JSP container will compile it automatically and convert it into 

servlet classes. 

JSP has some components-

1) Declaration - <%! declaration; [ declaration; ]+ ... %>

2) Scriptlet - <% code fragment %>

3) Expression - <%= expression %>

4) Directive-  <%@ directive attribute="value" %> 

JSP provide by default implicit Object e.g.(out, page, request, 

response, session and so on..)