Consistent HashCode() and Equals() results, but inconsistent TreeMap.containsKey() result

Posted by smessing on Stack Overflow See other posts from Stack Overflow or by smessing
Published on 2010-04-22T21:09:24Z Indexed on 2010/04/22 21:13 UTC
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I have the following object Node:

private class Node implements Comparable<Node>(){
     private String guid();

     ...

     public boolean equals(Node o){
         return (this == o);
     }

     public int hashCode(){
          return guid.hashCode();
     }

     ...

}

And I use it in the following TreeMap:

TreeMap<Node, TreeSet<Edge>> nodes = new TreeMap<Node, TreeSet<Edge>>();

Now, the tree map is used in a class called Graph to store nodes currently in the graph, along with a set of their edges (from the class Edge). My problem is when I try to execute:

public containsNode(n){
    for (Node x : nodes.keySet()) {
        System.out.println("HASH CODE: ");
        System.out.print(x.hashCode() == n.hashCode());
        System.out.println("EQUALS: ");
        System.out.print(x.equals(n));
        System.out.println("CONTAINS: ");
        System.out.print(nodes.containsKey(n));
        System.out.println("N: " + n);
        System.out.println("X: " + x);
    }
}

I sometimes get the following:

HASHCODE: true EQUALS: true CONTAINS: false N: foo X: foo

Anyone have an idea as to what I'm doing wrong? I'm still new to all this, so I apologize in advance if I'm overlooking something simple (I know hashCode() doesn't really matter for TreeMap, but I figured I'd include it).

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