StAX is the Streaming API for XML. Added as JSR173 to OpenJDK 6 and for earlier JDK USAGE IN OOo: The StAX API is used ONLY during build time for the saxon9 XSLT processor used for XSLT / XML based OOo filters, for build environements NOT using OpenJDK 6 or higher. Of the dual licenses, the GPL 2 license is suited for OOo during build-time.