CSC108/A08H Assignment #1 Announcements

This webpage contains announcements about A1.

27 Jan 2005: equals(Object) methods in ClassRoom and AVEquipment

Some people may find it easier to think of these methods and therefore to write them as: equals(ClassRoom) for the ClassRoom class, and equals(AVEquipment), for the AVequipment class. You may write them this way if you prefer, or you can stick with the original equals(Object) for both classes. Either way is acceptable.

25 Jan, 2005 Typo fixed on assignment page

An alert reader has brought to our attention that we wrote Classroom in a couple of places where we should have written ClassRoom.

Fixed.

21 Jan 2005: My test class crashes with a java.lang.NullPointerException. What is this? How can I avoid it?

A NullPointerException is Java's way of letting you know that somewhere you are referring to an object's method or variable when the object itself is null. This can happen if you did not properly initalize your objects in your test cases. You simply have to find these cases and fix them - java tells you where in your file the NullPointerException has originated.

One other way (perhaps the only other way) that this can happen is if you are comparing the AVEquipment of two ClassRoom objects, and one ClassRoom has no AVEquipment at all (so the value of the variable holding the AVEequipment object is null. In this case, you are probably calling on the equals() method of the non-existent AVEquipment object.

If this problem happens during our testing of your program, we will not take off points, but you might find it frustrating to have to deal with it during your own testing. To see how you may avoid this, please read the updated Hints section of the assignment page.