We have split the JSE class library into a number of 'modules'. You can see them laid out in the classlib area of the Subversion repository. Modules contain discrete sets of functionality and have well-defined dependencies between one another. The module interface is defined by an OSGi manifest (here is an example taken from the LUNI module). A separate page details the package-level componentization of the class library code.
Each class library module has a status page describing the Harmony development mailing list]. Development discussion is conducted on the [http://incubator.apache.org/harmony/mailing.html.
The Harmony website describes how to obtain and run the class library code.
Here are some applications that have been tried with the class library code. Please download the code, try running some applications, and report your findings here. It will be helpful if you record the code revision you are using, any special steps to run the application, and the results of your experiments!