The oral japa becomes mental and the mental japa finally reveals itself as being eternal.

Ramana Maharishi:  The object of mantra japa is to realise that the same japa is already going on in oneself even without effort. The oral japa becomes mental and the mental japa finally reveals itself as being eternal. That mantra is the person’s real nature. That is also the state of realisation.

Devotee:  Can the bliss of samadhi be gained thus?

Ramana Maharishi:  The japa becomes mental and finally reveals itself as the Self. That is samadhi