Switching from 1.3 to 1.4

I have decided to make the switch from Java 1.3 to 1.4, and along with it, I needed to implement new printing procedures. But, alas, these new procedures require classes that are not in java 1.3. Now, it turns out, many of my customers haven't and don't plan to upgrade to the newest jre. And if they attempt to run the program on java 1.3, they get errors concerning the fact that they can't find class definitions on the new 1.4 printing packages. Is there a way to detect which version I am in, before I import classes, and decide whether or not to import them? Thanks in advance.

[600 byte] By [ktulu_tco] at [2007-9-26 16:56:11]