libclassworlds-java binary package in Ubuntu Precise i386

 Classworlds is a framework for container developers who require complex
 manipulation of Java's ClassLoaders. Java's native ClassLoader mechanims
 and classes can cause many headaches and confusion for certain types of
 application developers. Projects which involve dynamic loading of
 components or otherwise represent a 'container' that can benefit from the
 classloading control provided by classworlds.
 .
 Classworlds provides a richer set of semantics for class loading than Java's
 normal mechanisms, while still being able to provide a ClassLoader interface
 to integrate seamlessly with the Java environment.

Source package