Metro is a high-performance, extensible, easy-to-use web service stack. Although historically an open-source part of the GlassFish application server, it can also be used in a stand-alone configuration. Components of Metro include: JAXB RI, JAX-WS RI, SAAJ RI, StAX (SJSXP implementation) and WSIT. Originally available under the CDDL and GPLv2 with classpath exception, it is now available under Eclipse Distribution License