Jar Jar Links: Ant utility that repackages Java libraries and embeds them in your own distribution

https://code.google.com/p/jarjar/

From the Google Code page:

Jar Jar Links is a utility that makes it easy to repackage Java libraries and embed them into your own distribution. This is useful for two reasons:

  • You can easily ship a single jar file with no external dependencies.
  • You can avoid problems where your library depends on a specific version of a library, which may conflict with the dependencies of another library.

Jar Jar Links includes an Ant task that extends the built-in jar task. The normal zipfileset element is used to embed jar files. A new rule element is added which uses wildcards patterns to rename the embedded class files. Bytecode transformation (via ASM) is used to change references to the renamed classes, and special handling is provided for moving resource files and transforming string literals.