java.lang.NullPointerexception in java

Question

I'm getting NullPointerException when I get set interface using subject.getSubjectHasProgram() in 2nd for loop. but subject.getSubjectHasProgram().size() show equall to 2 which is true what i want..!!

   Set<Subject> sub=(Set<Subject>)this.teacher.getSubjects();
   for (Iterator<Subject> iterator = sub.iterator(); iterator.hasNext();) {
       Subject next = (Subject)iterator.next();
       if(next.getID()==this.ID){
           this.Name=next.getName();
           System.out.println("Subject Name="+this.Name);
           this.CourseCode=next.getCourseCode();
           this.CreditHour=next.getCreditHour();
           **System.out.println("programscount="+next.getSubjectHasPrograms().size());**
            for (Iterator iterator2 = next.getSubjectHasPrograms().iterator(); iterator2.hasNext();){
                ProgramHasSubject programHasSubject = (ProgramHasSubject) iterator2.next();
                this.selectedPrograms.add(programHasSubject.getProgram_ID());
                System.out.println("Program ID : " + programHasSubject.getProgram_ID().getID());
                System.out.println("Program Name : " + programHasSubject.getProgram_ID().getName());
                System.out.println("Semester : " + programHasSubject.getSemester_ID());
            }
           break;
       }

   }

possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — Jens, Mar 16 '15 at 17:01
It's good practice to check for `null` even if you think it couldn't happen. — DigitalNinja, Mar 16 '15 at 17:01

score 0 · Answer 1 · edited Mar 16 '15 at 17:13

0

In the for loop you actually have two statements.

Iterator iterator2 = next.getSubjectHasPrograms().iterator();
and
iterator2.hasNext();

Have you verified that next.getSubjectHasPrograms().iterator(); does not return a null?

edited Mar 16 '15 at 17:13

Bono

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answered Mar 16 '15 at 17:08

Tim Hanna

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java.lang.NullPointerexception in java

1 Answers1