New to CVS: multiplatform projects

[kynn]

I'm new to CVS, and version control in general.  I understand the
basic idea of having a repository that preserves the history over time
of a software project.

My problem is that, for reasons too complex to go into here, I must
manage two parallel Java development projects.  These two projects are
99 % identical, except in the few areas in which one must be
compatible with v. 1.1.8 of the JDK, and the other must be compatible
with v. 1.3 of the JDK.

The v. 1.3 branch is our main area of development, while the v. 1.1.8
one is a secondary effort to satisfy a significant fraction of our
customers who have not upgraded from Mac OS 9 to Mac OS X.

Since the two versions are so similar, it would be convenient to
generate the v. 1.1.8 code by applying patches to the v. 1.3 code.
(If this were C/C++, the situation could be handled trivially with
conditional compilation, but, alas, Java does not have conditional
compilation.)  This seems like a problem well suited to CVS, but all
the introductory material I've read so far centers around the problem
updating versions over time, instead of the problem of generating one
secondary version from a primary one.

It seems to me that, schematically, things would look like this:

             1.3-branch-1.1     -->        1.1.8-branch-1.1 (patch)

                   |
                   v

             1.3-branch-1.2     -->        1.1.8-branch-1.2 (patch)
                   .                                  .
                   .                                  .
                   .                                  .

Hence, CVS would have to keep track of not only the diffs between
successive versions of the 1.3-branch code, but also the diffs between
the 1.1.8-branch and the 1.3 branch.  (It is not clear to me whether
it would be useful to keep track of the diffs between successive
1.1.8-branch versions, even if it were possible).

Can CVS be cajoled into helping with such a problem?

Thanks,

KJ