[kjetil]

Are you seriously suggesting that String incompatibilites are a big issues in Java?

String interning is specified in the JLS: http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#...

As far as I can tell, the substring "feature" has been there since Java 1.0 and was fixed in Java 7. Hardly groundbreaking stuff.