code: static int getRegisteredID (Connection connection, Object object) {
  		ObjectSpace[] instances = ObjectSpace.instances;
  		for (int i = 0, n = instances.length; i < n; i++) {
  			ObjectSpace objectSpace = instances[i];
  			// Check if the connection is in this ObjectSpace.
  			Connection[] connections = objectSpace.connections;
  			for (int j = 0; j < connections.length; j++) {
  				if (connections[j] != connection) continue;
  				// Find an ID with the object.
  				int id = objectSpace.objectToID.get(object, Integer.MAX_VALUE);
  				if (id != Integer.MAX_VALUE) return id;
  			}
  		}
  		return Integer.MAX_VALUE;
  	}
docs: Returns the first ID registered for the specified object with any of the ObjectSpaces the specified connection belongs to,
  or Integer.MAX_VALUE if not found.