People did use it and claimed it worked fine. Type "JPL" into Super Search and you'll get a ton of stuff back. These days you would probably be more likely to use Inline::Java.
Comment on Re: 2 cents of curiosity: JPL: What was it? How is it?
But note that JPL was coming at it from the other direction. You could think of it as an Inline::Perl for Java. To call
back into Java you just used an XS binding to JNI that made
Java classes and methods look Perlish.