The Sandbox module still has the no longer up-to-date Regexp Query that is based on Jakarta Regex. Because this project seems to be dead and the query is slow anyways, we should remove it.
LUCENE-6795 for more info why the hack is bad.
- relates to
LUCENE-6795 Remove all accessClassInPackage permissions / remove uses AccessibleObject#setAccessible() to make ready for Java 9 Jigsaw