javac dependencies

[Goldstein, Joel]

When using javac from the command line and combining sourcepath and
classpath it will compile dependencies if the class files do not exist or
are out of date.
I can't seem to be able to do this using the javac task for ant. Is it at
all possible? if yes how is it done? I tried using the sourcedir and
classpath but this doesn't seem to do it. any help would be appreciated
thanks 
Joel Goldstein
[EMAIL PROTECTED]