in hibernate , ASTPrinter receive the HqlTokenTypes  name by an int value.how did it do?
first ,useing Class.getFields to get all the fields,the use filed.get(null) to get the field's value that equals the int type will be returned.
so ,field.get(null) can return the field's value.if the parameter nonequals null,what it will return?
in addition,when use field.get(null),it use Modifier.isStatic( field.getModifiers() ) to check weather the filed is static.why it do this?if the field isn't static ,it will be what?
in my next test,
only public field can recieved by Class.getFields,even the page-privilege can't.
and only the static field can be return it's value when use filed.get(null),else will be error.