The JarClassLoader checks for information about packages by using the package name (net.example…) instead of the package path (net/example…) as i do not know if the current behavior is correct (i think it is not) the patch works as a fallback.
This problem came up when using sealed jars which excluded some packages from the seal. This information was not picked up correctly from the JarClassLoader so it refused to load the class/package. To be specific this was done with the openoffice Java SDK jars which are partly sealed and share packages over multiple jars.
The patch is against the 0_9_8_RC_2 tag