Assertions question

I am seeking the meaning of the system classes in Java. As there is a flag '-esa' that this will enable system assertions, which will allow the assertions assigned in the system classes.
And also for the flag '-ea' which stated that it allow all the assertions for all package and the system classes which do not have a class loader. I would like to know which system classes has class loader and which has not. Is there any information provided by Sun? As I search for it a few hrs but still get nothing.
Thanks~