Ohm's law of a circuit which has both a voltage source and current source
This only answers one part of your question, but I think it might be the main place where you are misunderstanding.


  How can the Ohm Law be applied in this case?


"Ohm's Law" isn't a law for all circuits. It's a description of one particular type of component: the ideal linear resistor. 

It doesn't matter how your power supplies are arranged in your circuit. Ohm's law has nothing to do with power supplies.

The general laws you want to consider that describe how currents and voltages relate in any circuit are Kirchoff's Current Law and Kirchoff's Voltage Laws. These laws, along with specific current-voltage relationships for each type of device (one of which is Ohm's Law), are the main tools for analyzing circuits.