private static boolean packageEquals(Class cl1, Class cl2) {
    return (cl1.getClassLoader() == cl2.getClassLoader()
        && getPackageName(cl1).equals(getPackageName(cl2)));
  }
Returns true if classes are defined in the same runtime package, false otherwise.
geode-core/src/main/java/org/apache/geode/pdx/internal/AutoSerializableManager.java