i'm working on an application on netbeans. when i click run it opens but when i click on a button for example to insert some data on database (mysql) is says java.lang.nullpointerException. i don't know how to solve it.. please somebody help me
The Java interpreter should tell you which class and what line of the source code is generating the exception. Take a look at that line and figure out why one of the objects involved is set to null instead of an instance of the object.
That's the most anyone can tell you without seeing the code.