WHEN I AM CALLING A SERVLET, I AM GETTING THIS ERROR

COULD ANYONE TELL ME WHAT DOES THIS MEAN????

SATISH


500 Internal Server Error
The servlet named cart at the requested URL

http://localhost:8080/servlet/cart
reported this exception: java.lang.ClassCastException. Please report this
to the administrator of the web server.

java.lang.ClassCastException at cart.doPost(Compiled Code) at javax.servlet.http.HttpServlet.service(Compiled
Code) at javax.servlet.http.HttpServlet.service(Compiled Code) at com.sun.server.ServletState.callService(Compiled
Code) at com.sun.server.ServletManager.callServletService(Compiled Code)
at com.sun.server.http.servlet.InvokerServlet.service(Compiled Code) at javax.servlet.http.HttpServlet.service(Compiled
Code) at com.sun.server.ServletState.callService(Compiled Code) at com.sun.server.ServletManager.callServletService(Compiled
Code) at com.sun.server.ProcessingState.invokeTargetServlet(Compiled Code)
at com.sun.server.http.HttpProcessingState.execute(Compiled Code) at com.sun.server.http.stages.Runner.process(Compiled
Code) at com.sun.server.ProcessingSupport.process(Compiled Code) at com.sun.server.Service.process(Compiled
Code) at com.sun.server.http.HttpServiceHandler.handleRequest(Compiled Code)
at com.sun.server.http.HttpServiceHandler.handleRequest(Compiled Code) at
com.sun.server.HandlerThread.run(Compiled Code)