StAX is a standard XML processing API that allows you to stream XML data from and to your application. This StAX implementation is the standard pull parser implementation for JSR-173 specification.

Woodstox is a high-performance XML processor. It implements StAX (Streaming Api for Xml, JSR-173), and supports XML 1.0 and 1.1(including full DTD validation), XML Namespaces 1.0 and 1.1. In addition to core Stax 1.0 API, Woodstox has extended API for pluggable bi-directional validation, both using DTDs (in-built), and external validation modules (for Relax NG, W3C Schema, using Sun MSV). With version 3.2 Woodstox also implements SAX API for improved interoperability.

XStream is a simple library to serialize objects to XML and back again. Features: Ease of use, no mappings, performance, clean XML, no modifications to classes, integration with XML libraries, full object graph support, customizable conversion strategies.