code: public boolean include(Archive source) {
          Module module = source.getModule();
          // skip system module by default
          return  !module.isSystem()
                      || configuration.rootModules().contains(source);
      }
docs: /*
  Tests if the given archive is requested for analysis.
  It includes the root modules specified in --module, --add-modules
  or modules specified on the command line
  
  This filters system module by default unless they are explicitly
  requested.