Element in two lists

Question

Hey,
I got a class for a tabbing page that is stored in an ArrayList A. This list A
contains various pages for a JTabbedPane. Only some of those pages will
also be stored in another ArrayList B. Hence list B will be smaller than A.
When I remove such a tabbing page in list A, I'll check also a certain
boolean if it is contained in list B, too.
How can I get the index now in list B in an elegant way? First I gave all of
those tabbing page classes an index variable for B, that I could check. My
problem was, it seems to be a bit clumsy and I need to update that variable
after each action (add/remove). Now I thought about in case I'd like to
remove a page, to run thru the list B and compare the elements in that list
directly with the one which is to be removed or compare just hashCode's of
these elements with the one to be removed, in case it would work?!
Which solution solves my problem best? - the first using an additional variable, comparing the elements or comparing just the hashCodes with the one element to be removed? TIA

Answer 1

don't know the 'best' way, but if the elements of B are added from A,
this might be all you need to do.
    Object o = listA.get(2);//<--2 is any number
    for(int x = 0,y = listB.size(); x < y; x++)
      if(listB.get(x).equals(o))
        listB.remove(x);
    }