def bootstrap_jar_classfiles(self):
    """Returns a set of classfiles from the JVM bootstrap jars."""
    bootstrap_jar_classfiles = set()
    for jar_file in self._find_all_bootstrap_jars():
      for cls in self._jar_classfiles(jar_file):
        bootstrap_jar_classfiles.add(cls)
    return bootstrap_jar_classfiles
Returns a set of classfiles from the JVM bootstrap jars.