Java EE (Java Enterprise Edition) General Discussion

Hi

I have a web app using tomcat 5.x and JSP. The user can enter form data into index.jsp and carry out a search of a db. From the results page (a plain html file generated by a java class) there is the option to start a new search. To do this at the start of index.jsp i invalidate the session (so the user doesn't get the results from the previous search) and start a new session. The problem is that when the user clicks new search from the results page i get a null pointer exception for index.jsp

java.lang.NullPointerException
	db.Handle.runSQLquery(Handle.java:143)
	db.RetrieveAdducts.getDBAdducts(RetrieveAdducts.java:55)
	org.apache.jsp.index_jsp._jspService(index_jsp.java:177)
	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
	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)

I have no idea why this is the error is intermittent and only occurs sometime usually after two searches but it could be more. I also sometimes have to restart the web server to get index.jsp to display again.

Im really stuck and would appreciate any help.
Thanks in advance