An object doesn't so much "implement" multiple threads as it winds up being called by multiple threads. When one object has methods called by two threads, the member variables on that object can be a real problem unless you manage them with synchronization. A class with thorough protection is called "thread safe". Otherwise it is "unsafe" for multi-threading applications.
Try the Sun Thread Tutorial or scroll up to the Threads etc. forum if you want to dig into the details! [ April 02, 2006: Message edited by: Stan James ]
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi