public PdxType getAutoPdxType() {
    if (unreadData != null && !unreadData.isEmpty()) {
      return null;
    }
    completeByteStreamGeneration();
    if (definingNewPdxType()) {
      return newType;
    } else {
      return existingType;
    }
  }
Returns the pdx type that can be used by the auto serializer to always serialize this class.
geode-core/src/main/java/org/apache/geode/pdx/internal/PdxWriterImpl.java