API to read weights from ckpt file

System information

• TensorFlow version (you are using): Nightly
• Are you willing to contribute it (Yes/No): No

Describe the feature and the current behavior/state.
This API would help in reading the weights from ckpt file. Currently, there is no such feature in the Java SDK but the same can be achieved in python via CheckPointReader.

Will this change the current API? How?
This shouldn't affect the preexisting API. It would be a simple addition over it.

Who will benefit with this feature?
I was developing a Federated Learning Application and was stuck at the issue where I was not able to get the weights from the ckpt file (Reason: No API in Java SDK) and neither could I write a signature method in tflite for the same (Reason: tflite doesn't support dynamic tensor shapes). So this would help promote active development in FL on Android clients.

Inizia confrontando la funzionalità richiesta del Java SDK con CheckPointReader di Python e verificando come vengono rappresentati i pesi dei checkpoint TensorFlow per i client Java e Android. Il lavoro è completato quando viene aggiunta una API Java che legge i pesi dai file ckpt senza modificare l'API preesistente, con un comportamento adatto ai casi d'uso del federated learning.