XDoclet is an open source code generation engine. It enables Attribute-Oriented Programming for java. In short, this means that you can add more significance to your code by adding meta data (attributes) to your java sources. This is done in special JavaDoc tags. This use of JavaDoc tags for attributes formed the original ideas for Java 5 Annotations.
XDoclet2 is the next generation of this technology. Based on Generama, it uses standard template engines such as Velocity and Freemarker for generation of text-oriented output, and Jelly for XML output. The function of XDoclet is to seed the generation contexts for these template engines.