Puzzling error on programmatic page load

Question

          I sincerely hope someone can help me here. I have no idea what's causing this
          particular error:
          <Oct 1, 2002 5:04:03 PM PDT> <Error> <HTTP> <101017> <[ServletContext(id=5808049,name=onstream,context-path=/onstream)]
          Root cause of ServletException java.lang.NullPointerException
          at jsp_servlet.__index._jspService(__index.java:255)
          at weblogic.servlet.jsp.JspBase.service(JspBase.java:27)
          at weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run(ServletStubImpl.java:945)
          at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:332)
          at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:242)
          at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:5360)
          at weblogic.security.service.SecurityServiceManager.runAs(SecurityServiceManager.java:721)
          Since that error is all fairly internal to WebLogic's servlet service, I have
          no idea where to start looking for a solution.
          Here's what I'm doing. I have a JSP page with access to some session beans.
          I'm not using any servlets, just JSP. The initial page load (index.jsp) is successful
          and populated with dynamic data. I then have a form submit that occurs that posts
          to the same page (index.jsp) which checks for the form variables at the top of
          the page.
          The user logs in, loads index.jsp, clicks on a link that launches the form submit,
          and index.jsp should pop back up with new data populated based on the user's selection.
          Instead, I get the exception shown above on mouse click.
          Any insight would be appreciated! Am I not allowed to request the JSP page in
          this manner? Is it possible that the error is in my JSP code, or is it a security
          violation of some sort? A misconfiguration?
          Thanks!
          

Answer 1

          "Eric Lai" <[email protected]> wrote:
          >
          >That's a fantastic suggestion actually--thanks. I didn't even think
          >to look for
          >that file.
          So the problem turned out to be the classic stupid java error whereby I was checking
          for string equality in an if statement using (String == String) rather than String.equals(String)
          method.
          Thank you, Kevin and Ann, for pointing me in the right direction.
          However, I am still not able to get the server to stop deleting the generated
          .java file. In order to grab __index.java I had to ctrl-c the command window
          immediately after the file had been generated. Kind of silly, but it worked.
          If anyone can tell me how to get it to save the files generated from Jsp2Java
          I'd greatly appreciate it.
          Thanks!
          >
          >However, the file does not exist apparently. The console tells me that
          >it has
          >created the file in the following directory:
          >
          >Generated java file: C:\bea\user_projects\mydomain\.\myserver\.wlnotdelete\onstream_onstream_1754841\jsp_servlet\__index.java
          >
          >However, all that resides in this directory is __index.class. It seems
          >that whatever
          >file is being generated is also being deleted after compilation.
          >
          >Is there a flag I can set that prevents this? I'm sorry if my ignorance
          >is shining
          >brightly.
          >
          >"Kevin L. Burns" <[email protected]> wrote:
          >>Go have a look at __index.java line 255. That is the Java code that
          >>was
          >>created from index.jsp. You should be able to figure out where in
          >>index.jsp you have a NullPointerException happening.
          >