Does Pattern.compile cache?
java, regex
Solution
I don't believe the results are cached and there's no evidence of such behaviour in the code or the documentation. It would (of course) be relatively trivial to implement such a cache yourself, but I would be interested in a use case in which such caching is beneficial.
Re. the comment below and String.split(), there's a different approach in that the code takes a distinct path for trivial 1 or 2 char patterns vs more complex regexps. But it still doesn't appear to cache.
Problem
It is likely an implementation detail, but for the Oracle and IBM JDKs at least is the compiled pattern cached or do we as application developers need to perform the caching of compiled patterns ourselves?