String is one that has changed pretty significantly - count and offset have been removed, only fields are hash and value now. This means String.substring is no

String is one that has changed pretty significantly - count and offset have been removed, only fields are hash and value now. This means String.substring is no longer an O(1) method, but it saves 8 bytes per string which is huge, and also avoids some of the wierd corner case GC/memory issues that substring/StringBuilder caused by hanging on to the reference