Load keras model in Java
Giving you some links which have worked:  

deploying-keras-deep-learning-models-with-java :  this uses DeepLearning4J, ND4J which supposedly you have tried already.

tensorflow-keras-java  

And same question is asked here - converting-keras-in-python-to-java . It uses KerasModelImport.importKerasSequentialModelAndWeight

You should give HDF5 file operation java examples: hdf-java . It would be helpful if you want to change the weights yourself

Please comment if you have already tried all these already.