Safe to delete earlier versions of Java runtime?

I received a “low disk space” warning this AM on my Windows XP machine. Is it safe to delete any of the following Java programs:

J2SE Runtime Environ. 5.0 Update 10
J2SE Runtime Environ. 5.0 Update 11
Java 2 Runtime Environ.SE v. 1.4.0_03
Java 2 Runtime Environ.SE v. 1.4.1_02
Java(TM) SE Runtime Environ. 6 Update 1

I have done all the usual things about clearing cookies, cache, deleting unnecessary programs. I need a little more space.

Thanks.