Remove method: push in the right direction

Question

Hello everybody. I am new to java and programming all together ( i have been programming for about 3 weeks or so). I am sorry if the question is simple. I seem to be having a problem with remove function.
Basically I have class Task(which has an ID, brief description, dueDate etc...). I also have a task TaskList as well as a class Date . The taskList has attributes an array of type Task with a length of 10. It also has methods to add, remove tasks as well as display the arrays contents. The remove method is what is causing me problems.
My general thinking was to find the arraycell containing the reference that points to the taskId that is to be removed. Afterwards I wanted to assign a null value to the cell containing the task to be removed. Then i would begin by swapping references until the null value is in a way where the array has no wholes in it.
I have tried different variations of the same logic but either it does absolutely nothing, either I get a nullpointer exception. I am not looking for an explicit answer, just a nudge in the right direction. Is the general idea I proposed earlier worth anything. Can I affect a null value to an arraycell containing a reference to an object.
Thank you in advance for any help.
P.S: Again I apologize, for I know this must be a question that keeps coming up over and over...
Oh, before I forget, are there any good textbooks that explain ina detailed manner class relationships, particularly dependancy, aggregation and inheritance.

Answer 1

Why not use a List instead? Lists are dynamic, i.e. they can add or remove
elements anywhere, closing the gap (i.e. there's no need to stuff nulls in there).
Something like this:public class TaskList {
   private List l= new ArrayList();
   public void add(Task t) { l.add(t); }
   public boolean remove(Task t) { return l.remove(t); }
   // all the other functionality you want goes here ...
}kind regards,
Jos