public Collection keyCollection() {
        if (keyCollection == null) {
            keyCollection = new AbstractCollectionView() {
                public long size() throws ObjectManagerException {
                    return AbstractTreeMap.this.size();
                }

                public Iterator iterator() throws ObjectManagerException {
                    return makeTreeMapIterator(
                    new AbstractMapEntry.Type() {
                        public Object get(AbstractMapEntry entry) {
                            return entry.key;
                        }
                    });
                }
            };
        }
        return keyCollection;
    }
public Collection keyCollection ( ) { if ( keyCollection == null ) { keyCollection = new AbstractCollectionView ( ) { public long size ( ) throws ObjectManagerException { return AbstractTreeMap . this . size ( ) ; } public Iterator iterator ( ) throws ObjectManagerException { return makeTreeMapIterator ( new AbstractMapEntry . Type ( ) { public Object get ( AbstractMapEntry entry ) { return entry . key ; } } ) ; } } ; } return keyCollection ; }
Answers a Collection of the keys contained in this TreeMap. The set is backed by
this TreeMap so changes to one are relected by the other. The Collection does
not support adding.

@return a Collection of the keys