Java tutorials - Class/Object/Encapsulation

tutorial1

Identify the classes their properties and methods in the following problem description

I want to model a basic cellphone for an outgoing call. The phone should be able to dial a number, 
initiate a call, ability to talk after successfulconnection to the dialed cell phone and then 
disconnect. The cellphone should be enough battery to initiate a call and if the battery is dead 
it should end the call gracefully. The phone should have ability to be switched on switched off. 
For obvious reasons the user of the phone can make a call only if the phone is switched on. Also 
For simplicity assume on 1 call is allowed at any given time (no hold and conference capabilities 
are required).