This post originated from an RSS feed registered with Java Buzz by Norman Richards. Original Post: I'm lonely, buy me lunch Feed Title: Orb [norman richards] Feed URL: http://members.capmac.org/~orb/blog.cgi/tech/java?flav=rss Feed Description: Monkey number 312,978,199 Latest Java Buzz Posts Latest Java Buzz Posts by Norman Richards Latest Posts From Orb [norman richards]

Someone asked about marker interfaces in a thread at javaranch today. I was amused by Stan James' analogy explaining the difference between interfaces with methods, and marker interfaces with no declared messages.

It's just there so someone can ask if it's there. It's a way of declaring you want to be treated in a special way at some point, but doesn't declare that you have any particular methods that can be called.

If I say "I can fly a helicopter!" somebody might ask me to do it, so I have to implement the methods.

If I say "I'm lonely" nobody will expect me to do anything special, but they might buy me lunch.

I thought that was an interesting way to explain marker interfaces. Of course, the need for marker interfaces will be eliminated (or at least significantly reduced) with JSR 175. You won't need to implement loneliness, you can simply declare yourself @Lonely.