Thanks for the response. I think I worded it wrong. I'm OK with writing the java code.
The actual concept of building the tree from a logic standpoint is probably where I'm going wrong.
I understand the concept of the Decision Tree just not how to go about building one programmatically...so I guess psuedo code is probably what I'm looking for...so this may be the wrong forum.
Also look at the Wikipedia article. It shows diagrammatically how a decision tree can be put together, so quickly you can see that you have nodes, with weighted connections to other nodes. Those are going to be your first 2 programming constructs...