@AfterClass
  public static void afterClass() {
    InternalInstantiator.unregister(Payload.class, (byte) 22);
    InternalInstantiator.unregister(Key.class, (byte) 21);
  }
This class makes sure that instantatiors are persisted to disk and can be recovered.
geode-core/src/integrationTest/java/org/apache/geode/DiskInstantiatorsJUnitTest.java