First , please understand its feature :
* no need to instantiate a instance, i.e. simply you can just write: AutoTrace.start();
* All instances will share one static method, consider the consistency when the method operate a static (global) variable. [ as to its local variables, each thread has self stack. This's similar to non-static method ]
Then to consider whether to declare as static :
* If you really no need to construct a java instance before call its method
* the static variable of the static method is immutable or not / no need to consider its consistency [ i.e. locking ]
....