If you have these arrays in something inheriting from Collection, you can just use collection.containsAll( otherCollection ) from the Collection interface. However, you’ll also need to compare the lengths of the two to verify that one set isn’t a superset of the other.
(Thanks go to Aardvarkk and piegames.)
http://docs.oracle.com/javase/6/docs/api/java/util/Collection.html#containsAll(java.util.Collection)
Note: This will work up to a point. This is defined to check for at least one of any element existing. That is, if you have 3 a values in one collection, and 7 a values in the other, that will not necessarily cause it to call them unequal.
Examples:
[a, b, c] == [c, a, b] // Works -- Mixed order
[a, b, c, d, d] == [a, b, d, c, d] // Works -- Mixed order with repeats
[a, b, c, d, d] == [a, b, b, c, d] // FAILS -- Different repeats
[a, b, c, d, d] != [a, b, c, d] // Works -- Length differs with repeats
[a, b, c, d] != [a, b, c] // Works -- Length differs
[a, b, d] != [a, b, c] // Works -- Disjoint sets