Question

This is a pice of my code :

  ArrayList<String> Alist= new ArrayList<String>();
  ArrayList<String> Blist= new ArrayList<String>(); 

  Alist.add("gsm");
  Alist.add("tablet");
  Alist.add("pc");
  Alist.add("mouse");

  Blist.add("gsm");
  Blist.add("something");
  Blist.add("pc");
  Blist.add("something");

so i have two array list i want to compare all items and check if they are not equal and if they are to print out only the items that are not equal.

so i make something like this:

http://postimage.org/image/adxix2i13/
sorry for the image but i have somekind of bug when i post here a for looop.

and the result is :

not equals..:tablet
not equals..:pc
not equals..:mouse
not equals..:gsm
not equals..:tablet
not equals..:pc
not equals..:mouse
not equals..:gsm
not equals..:tablet
not equals..:pc
not equals..:mouse
not equals..:gsm
not equals..:tablet

i want to print only the 2 that are not equal in the example they are gsm and pc

not equals..:gsm
not equals..:pc

Answer 1

Don’t use != to compare strings. Use the equals method :

if (! Blist.get(i).equals(Alist.get(j))

But this wouldn’t probably fix your algorithmic problem (which isn’t clear at all).

If what you want is know what items are the same at the same position, you could use a simple loop :

int sizeOfTheShortestList = Math.min(Alist.size(), Blist.size());
for (int i=0; i<sizeOfTheShortestList; i++) {
    if (Blist.get(i).equals(Alist.get(i))) {
        System.out.println("Equals..: " + Blist.get(i));
    }
}

If you want to get items that are in both lists, use

for (int i = 0; i < Alist.size(); i++) {
    if (Blist.contains(Alist.get(i))) {
        System.out.println("Equals..: " + Alist.get(i));
    }
}