Symmetric difference of two Java arrays

Question

I have two arrays

 String[] ID1={\"19\",\"20\",\"12\",\"13\",\"14\"};

 String[] ID2={\"10\",\"11\",\"12\",\"13\",\"15\"};  

How can I get

Answer 1

It looks like XOR operation ;)

Please describe your needs a little bit more directly. Pseudocode:

foreach s in ID1 {
  if(ID2.contains(s)) {
    ID2.remove(s)
  } else {
    ID2.add(s)
  }
}

ID2 will contain your result. In assumption that there are not duplicates in both arrays.

Answer 2

Seems like you want the union of the two sets (no duplicates, right?) minus the intersection:

Set<Integer> union = new HashSet<Integer>(Arrays.asList(ID1));
union.addAll(Arrays.asList(ID2);

Set<Integer> intersection = new HashSet<Integer>(Arrays.asList(ID1));
intersection.retainAll(Arrays.asList(ID2);

union.removeAll(intersection);

// result is left in "union" (which is badly named now)

(I changed your String to Integer, which seems to fit the data better, but it would work with String the same way)