public List<String> getExtraModules() {
		return extraModules == null ? Collections.<String>emptyList() : Collections.unmodifiableList(extraModules);
	}
public List < String > getExtraModules ( ) { return extraModules == null ? Collections . < String > emptyList ( ) : Collections . unmodifiableList ( extraModules ) ; }
Returns the list of additional modules that should be included ahead
of this module build in the layer

@return The list of before modules.