Referencing a external java libraries from pl/sql

 I'm looking to make use of some Apache Commons Java libraries in a Java class that I can call from a PL/SQL stored procedure.  First, is this possible?  Second, is this a "loadjava" task or would I manually copy the jar to the server's "classpath" directory.  I have written and used Java classes in the past, but they only required the standard libraries.
Thanks in advance