Both classes define a method which repeatedly prints out "NO! I'M LARS ULRICH!!", called go(). The main(String[] args) method is the one that is set in motion by default, and that creates an instance of the class and sets its go() method in motion. So, in BASIC, it's essentially:

10 PRINT "NO! I'M LARS ULRICH!!"
20 GOTO 10

just rendered into Java.