public static boolean isSerializedNull(byte[] serializedForm) {
    return serializedForm.length == 1 && serializedForm[0] == DSCODE.NULL.toByte();
  }
returns true if the byte array is the serialized form of a null reference

@param serializedForm the serialized byte array
geode-core/src/main/java/org/apache/geode/internal/InternalDataSerializer.java