Java EE (Java Enterprise Edition) General Discussion

this error doesnt make sense to me at all:

ok a jsp(update.jsp) which calls a jsp to save details called saveempdetails.jsp

once commited another jsp(workexp.jsp) is called like....

pageContext.forward( "workexp.jsp" );

when i then use the add record button i get this error:

org.apache.jasper.JasperException: An exception occurred processing JSP page /Updates/saveempdetails.jsp at line 35
32: String companyname = request.getParameter( "companyname");
33: out.println(companyname);
34: String rolename = request.getParameter( "rolename");
35: int empid = Integer.parseInt(request.getParameter( "empid"));
36: String forename = request.getParameter( "forename");
37: String surname = request.getParameter( "surname");
38: String housename = request.getParameter( "housename");

	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:555)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:803)


root cause 

java.lang.NumberFormatException: null
	java.lang.Integer.parseInt(Integer.java:415)
	java.lang.Integer.parseInt(Integer.java:497)
	org.apache.jsp.Updates.saveempdetails_jsp._jspService(saveempdetails_jsp.java:89)
	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:390)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

but if i refresh the page and then click the add record button i do not get this error...?? makes little sence to me

the add reccord javaScript looks like this:

<script language="javascript">
        function submitForm(process){
          
          if(process=="add"){
             var val = document.myForm.hiddenField.value;
             document.myForm.hiddenField.value = parseFloat(val)+1;
             document.myForm.submit();
          }