Messages

What is a message?

• Objects communicate by sending messages.
• Messages are implemented as calls to another objects methods (subroutines).
• Information is sent to called object in the method's arguments.
• Information is sent back to the calling object by the return value.

Objects communicate with messages. Lifted from The Java Tutorial (Sun Microsystems).

You send a message to your bicycle using one of its methods. Lifted from The Java Tutorial (Sun Microsystems).

The Incredible Machine demonstration

• Objects send messages to other objects in several ways:
  • By hitting them
  • By steam
  • By cannon ball
  • ...