Transmission Line with Short Circuit and Inductor as Loads
how can it start to oscillate on its own 


It will not oscillate in steady state (assuming either the lines or the inductor are real devices with some loss). If the inductor is initially charged (by some other circuit, not shown in your diagram), it may oscillate for some time until the stored energy is dispersed through the loss mechanisms.


  to make an LC circuit oscillate, the capacity must be pre-charged at the time of closing the switch


Not true. You could leave the capacitor uncharged, and pre-charge the inductor (with an initial current) instead.


  Oscillation means voltage + current and so energy. And it cannot create energy from 0.


Correct. This circuit will not start oscillating on its own. It needs some other way to obtain an initial stored energy before it can oscillate. 

In the real world (no lossless components) it will (like any other oscillator) need continuous energy input to maintain a steady state oscillation.