Android :: Pass Data Between Activities - HashMap Of WeakReferences To Objects

I am trying to pass a custom object to one activity from another. What I would like to use is the HashMap of WeakReferences, but the description isn't clear, at least to me. From above URL: "A HashMap of WeakReferences to Objects. You can also use a HashMap of WeakReferences to Objects with Long keys. When an activity wants to pass an object to another activity, it simply puts the object in the map and sends the key (which is a unique Long based on a counter or time stamp) to the recipient activity via intent extras. The recipient activity retrieves the object using this key."

MyObject object = new MyObject(); HashMap map = new HashMap(); WeakReference reference = new WeakReference(object); map.put(reference.hashCode(), reference);
Intent i = new Intent(myIntent); i.putExtra(map);

I know this is probably way off but I can't figure out how this is intended to be implemented based on the description. Are the keys hashcodes, user defined, or what? It sounds like all that is passed is a HashMap containing the key values but how is the object retrieved with just the key? I couldn't find any code examples or useful documentation on this method of passing objects