Hi, in our immutable map implementations, it's unnecessary for getOrDefault to check containsKey(key) in case get(key) returns null. This follows since null values are disallowed.
Overriding the method with an implementation is a reasonable optimization, for example a 50% improvement on the added microbenchmark. I found this opportunity when looking at startup profiles, so yes, there's a tiny startup improvement, too. :-) Webrev: http://cr.openjdk.java.net/~redestad/8238684/open.00/ Bug: https://bugs.openjdk.java.net/browse/JDK-8238684 Testing: tier1+2 (ongoing) Thanks! /Claes
