The ASF is made up of over 100 top level projects that cover a wide range of technologies. Chances are if you are looking for a rewarding experience in Open Source, you are going to find it here.
XPath for Java Objects
A Java-based implementation of XPath 1.0 that, in addition to XML processing, can inspect/modify Java object graphs (the library's explicit purpose) and even mixed Java/XML structures.
Library to use configuration/preferences of various sources and formats.
Apache Rat improves accuracy and efficiency when reviewing and auditing releases.
Apache Rat improves accuracy and efficiency when reviewing and auditing releases. It is heuristic in nature: making guesses about possible problems. It will produce false positives and cannot find every possible issue with a release. It's reports require interpretation. Apache Rat was developed in response to a need felt in the Apache Incubator to be able to review releases for the most common faults less labour intensively. It is therefore highly tuned to the Apache style of releases.