The Java Wikipedia API (Bliki engine) is a parser library for converting Wikipedia/Mediawiki syntax to HTML. It supports wiki tags for bold, italic, headers, nowiki, source, table of contents, tables, lists, categories, footnotes (references), images, syntax highlighting of source code fragments, templates, and template parser functions.
Niocchi is a Java crawler library implementing synchronous I/O multiplexing. This specific type of implementation allows crawling tens of thousands of hosts in parallel on a single low end server. Niocchi has been designed for big search engines that need to crawl massive amount of data, but can also be used to write no-frills crawlers.
VectorGraphics2D can export Java painting operations to Encapsulated PostScript (EPS), Scalable Vector Graphics (SVG), or Portable Document Format (PDF) files. It supports the rendering of all geometric shapes provided by the Java language. More advanced features like transparency or clipping paths can be used as well. It has a very small footprint and can be easily used as a replacement for Java's java.awt.Graphics2D class.