Have you tried to use .equals to compare Arrays of identical primitives only to find it always returns false? I was surprised using such an Array for the key of a Map. I expected equals to return true, but Java's dynamically generated class returns false unless the comparison is to the same actual object. I am considering filing a jdk issue, but first wanted to check and see what others expected equals to do in this case. Again, this is a Java issue, not an IDEA.