Re: ABCL in a multi-threading environment

Yes, ABCL threads are Java threads underneath.

Store the per-thread data in a java.lang.ThreadLocal variable, then it will 
be garbage collected when the thread ends.
(If Thread A may want to access Thread B's per-thread data, then that'll 
need more thought.)

The bordeaux-threads library's MAKE-LOCK creates a Java ReentrantLock.
Follow the usual rules for portably and correctly accessing data from 
multiple threads.
https://www.cs.umd.edu/~pugh/java/memoryModel/jsr-133-faq.html

Vibhu