Hi all am encoutering a challenage here how to u map a tree structure to a table?

e.g

public class Node{
Node parent;
List child=new ArrayList();//Stores a list of child nodes
}

And all the data is mapped to a table so in order to find the root i probably have a node where the parent is null.

How do i do the mapping for this table? How do i map the parent 'Node' back to the table itself?

I feel that i would probably need to create a composite type for Node so to put it in the mapping file but i have no idea how to let hibernate know that the object is mapping to the same table.