code: private void scanPlatformPath(PackageSymbol p) throws IOException {
          fillIn(p, PLATFORM_CLASS_PATH,
                 list(PLATFORM_CLASS_PATH,
                      p,
                      p.fullname.toString(),
                      allowSigFiles ? EnumSet.of(JavaFileObject.Kind.CLASS,
                                                 JavaFileObject.Kind.OTHER)
                                    : EnumSet.of(JavaFileObject.Kind.CLASS)));
      }
docs: Scans platform class path for files in given package.