Without any information about your facts (shadow or not) and rules only very general suggestions are possible.
NPE's may come up when a slot usually holding an object is null and you call a method. Less obvious are cases when a java.lang.Integer (or similar) is null and the value is used in an arithmetic operation or a comparison; then unboxing causes the NPE. -W On Mon, Nov 9, 2009 at 10:29 AM, Patricia Charlton < patricia.charl...@pobox.com> wrote: > Hi there, > > I'm developing an inference engine using JESS. I am using protege and JESS > TAB integration and running JESS from the protege environment. > > Occasionally I get an error nested exception is: null. It does not happen > each time I run the application and I have tested each part independently. > It is also not always with the same inference about a particular concept. > > Is there a known problem between the integration environment where for > example concept pointers may get dropped? > > I am currently at a loss as to how to fix this. It maybe a problem with > protege/jess or jess tab. > > (current environment is MAC, Protege 3.4 and Jess 7.1) > > Any help or pointers at this stage would be great. > > Kind regards, > Patricia > > > > -------------------------------------------------------------------- > To unsubscribe, send the words 'unsubscribe jess-users y...@address.com' > in the BODY of a message to majord...@sandia.gov, NOT to the list > (use your own address!) List problems? Notify owner-jess-us...@sandia.gov. > -------------------------------------------------------------------- > >
