am 1cf3b27: Test for null object in the Get<Type>Field and Set<Type>Fiel

Merge commit '1cf3b27e857824af08bab76489b6e25a213edc8d'

* commit '1cf3b27e857824af08bab76489b6e25a213edc8d':
  Test for null object in the Get<Type>Field and Set<Type>Field JNI functions.