This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
In your other thread you had asked about using the MutableTreeNode. This is my response:
The MutableTreeNode is a node on a tree. You should read the tutorial I mentioned in the other post. It has a section about using TreeModels, and the DefaultTreeModel. Even if you aren't using the JTree for display purposes it may be a good structure to look over for representing non-binary tree structures.
It really is just a bunch of links between nodes (parent and lists of children) with identifiers for leaf nodes.