Again i got the same errors.the errors are as follow
InsertServlet.java:3: package javax.servlet does not exist
import javax.servlet.*;
^
InsertServlet.java:4: package javax.servlet.http does not exist
import javax.servlet.http.*;
^
InsertServlet.java:7: cannot find symbol
symbol: class HttpServlet
public class InsertServlet extends HttpServlet{
                                   ^
InsertServlet.java:8: cannot find symbol
symbol  : class HttpServletRequest
location: class InsertServlet
    public void doPost(HttpServletRequest req,HttpServletResponse res) throws Se
rvletException,IOException {
                       ^
InsertServlet.java:8: cannot find symbol
symbol  : class HttpServletResponse
location: class InsertServlet
    public void doPost(HttpServletRequest req,HttpServletResponse res) throws Se
rvletException,IOException {
                                              ^
InsertServlet.java:8: cannot find symbol
symbol  : class ServletException
location: class InsertServlet
    public void doPost(HttpServletRequest req,HttpServletResponse res) throws Se
rvletException,IOException {
                                                                              ^