This seems to be a common homework question, so please have a look at the "Which topics are not welcome in the newsgroup?" to understand why this answer is intentionally vague.

If the fixed layout of JTree suits your needs, you could start reading the JTree API documentation.

Or you could use a simple (recursive) algorithm. E.g

x(node) = K * level(node), and

y(node) = M * inorder_rank(node).

gives very ugly trees, but trees. If this doesn't get you started, ask your professor or tutor for more hints. Consult your text book about (inorder) tree traversal, and consult

http://home.earthlink.net/~patricia_shanahan/beginner.html