Indicates the classpath locations that should be scanned when resolving types not defined
in a PathResolver location.
This method need not return a complete classpath, due to the complexity of determining transitive
relationships. The method may also return Stringss that reflect non-existent paths (as the
build system has yet to download them). The classpath computation is therefore on a "best effort" basis only.
An implementation must guarantee to send a notification event should there be a change to the calculated classpath.
An implementation must also ensure that no String presented is nested within any
PathResolver.getSourcePaths() location.
The String elements are in canonical file format.
- Returns:
- an unmodifiable representation of classpath locations to be used, excluding locations
that are included by
PathResolver.getSourcePaths() (never null, but may be empty)