JavaCC is a parser/scanner generator for java.

Avro is a row-oriented remote procedure call and data serialization framework that produces a compact binary format.

ZooKeeper server

The core parser functionality. This may be all you need.

JSqlParser parses an SQL statement and translate it into a hierarchy of Java classes. The generated hierarchy can be navigated using the Visitor Pattern.

Maven 3 Plugin for processing JavaCC grammar files.

Jackrabbit content repository implementation

Cobertura is a free Java tool that calculates the percentage of code accessed by tests. It can be used to identify which parts of your Java program are lacking test coverage.

PMD Java

PMD Core

A CSS parser which implements SAC (the Simple API for CSS).