JHighlight is an embeddable Java syntax highlighting library that supports Java, Groovy, C++, HTML, XHTML, XML, and LZX languages and outputs to XHTML. The library can be used in several ways: embedded into another tool (for instance a blog or forum), through the command-line to generate highlighted files locally, or as a servlet filter to highlight source files on your server on-the- fly. It also supports RIFE templates tags and highlights them clearly so that you can easily identify the difference between your RIFE markup and the actual marked up source.
OpenGrok is a fast and usable source code search and cross reference engine. It helps you search, cross-reference, and navigate your source tree. It can understand various program file formats and version control histories like Mercurial, Bazaar, Git, ClearCase, Perforce, SCCS, RCS, CVS, or Subversion. In other words, it lets you grok (profoundly understand) the source.
Restlet is a REST framework for Java. It supports all REST concepts (Resource, Representation, Connector, Component, etc.) and is suitable for both client and server Web applications. It supports major Web standards like HTTP, SMTP, XML, JSON, WADL, and Atom. Many extensions are also available to integrate with Servlet, Spring, Jetty, Grizzly, Simple, JAXB, JAX-RS, JiBX, Velocity, or FreeMarker. A GWT version is also available.