Cocoa Dictionary like Java HashMap

COCOA has a couple dictionary objects. One is changeable (mutable) and one is not.

NSDictionary and NSMutableDictionary

NSMutableDictionary *dict = [NSMutableDictionary dictionary];

[dict setValue:[NSDate date] forKey:@"now"];

[dict setValue:[NSDate dateWithTimeIntervalSinceNow:-60] forKey:@"1 minutes ago"];