Splay trees and compareTo

Three questions. 1 and 3 should be very simple, and that's why i am not breaking them up into three q's.

//QUESTION 1 (Line marked below)
I get this error:
The method compareTo(Object) is undefined for the type Object

why? _root.getKey returns the key value in the root (type TreeNode), which is type Object, the same as key, and the value that compareTo expects.

//QUESTION 2 (Line marked below)
I have a splay method which must have the contract splay(TreeNode t), not splay(Object t).  So, assuming the TreeNode with the _key value == key, how do I get this TreeNode so that I can pass it to the splay method? As I am writing this, I realize I have also created a find(Object key) method which looks like this:
        public Object find(Object key){
            if (_root == null) return null;
            splay(key);
              if(_root.getKey().compareTo(key) != 0) return null;
              return _root.getKey();
      }
but I am unable to make the mental connection as to how I might use find (if possible) to get a TreeNode existing in my splayTree that I could pass to my splay(TreeNode t) method.  Suggestions??


//QUESTION 3
What does this mean as a for loop?
for (;;){//THIS LINE
//Loop contents here
}

The Code:

      public Object remove(Object key){
            TreeNode x;
            splay(key);                   //QUESTION 2
            if (key.compareTo(_root.getKey()) == 0) {   //QUESTION 1
            // Now delete the root
            if (_root.getLeft() == null) {
                _root = _root.getRight();
            } else {
                x = _root.getRight();
                _root = _root.getLeft();
                splay(key);                  //QUESTION 2
                _root.setRight(x);
            }
            }
      }