Help with HashMap in java

[toby]

I have a hashmap setup in the following way:

Key Value
0 XXX
1 XYX
2 XYY
3 XXX
4 YXX
5 YXX

I currently can check if a given value is in the map no problem. But once I determine that a value is in the map, how do I return the key or keys at which a given value was found? This is crucial for me to be able to do. I know values are not unique but there has to be a way to return which key or keys have that value.
Thanks

[Seemster]

// Create a hash table
Map map = new HashMap(); // hash table
map = new TreeMap(); // sorted map

// Add key/value pairs to the map
map.put("a", new Integer(1));
map.put("b", new Integer(2));
map.put("c", new Integer(3));

// Get number of entries in map
int size = map.size(); // 2

// Adding an entry whose key exists in the map causes
// the new value to replace the old value
Object oldValue = map.put("a", new Integer(9)); // 1

// Remove an entry from the map and return the value of the removed entry
oldValue = map.remove("c"); // 3

// Iterate over the keys in the map
Iterator it = map.keySet().iterator();
while (it.hasNext()) {
// Get key
Object key = it.next();
}

// Iterate over the values in the map
it = map.values().iterator();
while (it.hasNext()) {
// Get value
Object value = it.next();
}