Question

What happens in the following case?

Timer t = new Timer();
t.schedule(...);
t = new Timer();

Specifically, what happens to the the tasks that I’ve scheduled on Timer t after I’ve assigned a new instance of Timer to t?

Answer 1

They doesn’t go away. Each Timer object is associated with a background process. Even when you remove all references to your Timer in your program, the background process will still continue to run (it holds it’s own reference to the object). Because of this, the object will not be subject to garbage collection.

See the official documentation for details.

Corresponding to each Timer object is a single background thread that is used to execute all of the timer’s tasks, sequentially … After the last live reference to a Timer object goes away and all outstanding tasks have completed execution, the timer’s task execution thread terminates gracefully (and becomes subject to garbage collection). However, this can take arbitrarily long to occur.