Sorry Brian did I confuse you. Well I only wanted to pointed out the order of evaluation of the assertions command line arguments, it's left to right so if you say java -enableassertions -disableassertions <filename> then assertions would be disabled. As for the various assertions command line options they are :
-ea or -enableassertions
-da or disableassertions
-esa or enablesystemassertions
dsa or disablesystemassertions
Try this javaranch
thread and this
tutorial at sun's site.