I've often wished that CharSequence had getChars methods, as many of the concrete implementations already do. In jdk8 with default methods, this is possible! This will make some of the String code a little nicer and more efficient.
Here's a preliminary patch in this direction, that overlaps with some of the work done in 6206780: (str) Forwarding append methods in String{Buffer,Builder} are inconsistent Summary: update StringBuilder & StringBuffer to consistently handle forwarding to AbstractStringBuilder. Some additional cleanup (removal of refs to sub-classes from AbstractStringBuilder) http://cr.openjdk.java.net/~martin/webrevs/openjdk8/getChars/ If we have consensus that this is a good idea, I can flesh this out.