This addresses an issue reported here (German only) and reproduced by me on Domino 9.0.1FP3.

On current Domino versions, getting a handle on java.util.regex.Pattern.compile(String, int) from LS2J no longer works. An exception “LS2J Error: Threw java.lang.InternalError” will be thrown.
You can, however, get the handle by iterating over all methods and selecting the desired one.

This release makes use of this workaround.