Hi Sherman, I'd like you to do a code review.
http://cr.openjdk.java.net/~martin/webrevs/openjdk7/Formatter.parse/ Synopsis: Optimize Formatter.parse (including String.printf) Description: Formatter is not as efficient as it could be. Here's a low-hanging fruit optimization that creates fewer objects, and uses the idiom return al.toArray(new FormatString[al.size()]); I'm sure additional optimizations are possible. Results: about 10-20% faster on in-house microbenchmarks of String.printf Martin