using an object from different package

Asked Sep 19 '22 at 19:55

Active Sep 19 '22 at 19:55

Viewed 16 times

I have a problem, I have a package event which contains a class student in this class I have this method

public void addEvents( Event e) {
    if(e!=null)
        events.add(e);          
}

in a second package I have created an event and I want to call the above method to add the event created to a ArrayList

event.setDateEvent(new Date(day,month,year));
student.addEvents(event);

this error is displayed

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "java.util.ArrayList.add(Object)" because "this.events" is null
    at event.Student.addEvents(Student.java:48)
    at test.StudentTest.main(StudentTest.java:43)

edited Sep 19 '22 at 19:55

Federico klez Culloca

26,308
17
56
95

asked Sep 19 '22 at 19:55

boutheina

Did you initialize `events` in the first class? – Federico klez Culloca Sep 19 '22 at 19:57
no I don't initialize event in the first class – boutheina Sep 19 '22 at 20:02
I think that the problem because the two classes are not in the same package but I can't resolve this – boutheina Sep 19 '22 at 20:05
The fact they are in different packages is irrelevant. You just need to initialize `events`, either in `Student`'s constructor or from a public method in `Student` you call from `StudentTest` or, if `events` is public, directly from `StudentTest`. – Federico klez Culloca Sep 20 '22 at 06:30

using an object from different package

0 Answers0