ORO is a regular expression/text processing API for Java. It is an open source project licensed under the Apache Software Foundation. ORO provides Perl 5 and awk regular expression functionality and well as other text processing tools.
Daniel F. Savarese and Jon S. Stevens are primarily responsible for writing the code.
At the time of this writing, ORO is at version 2.0.5.
Personally, I find ORO in a great way of converting Perl programmers over to Java.