java - When would the garbage collector erase an instance of an object that uses Singleton pattern?

Question

When would the garbage collector erase an instance of an object that uses Singleton pattern?

Does an object hang around any longer than a regular object?

How can you manually force deletion/garbage collection of an object in Java?

Thanks.

Answer 1

There's a static reference to a singleton, so it won't be eligible for garbage collection until the classloader is eligible for garbage collection.

You can't force any object to be garbage collected; you can request that the garbage collector runs with System.gc() but it's only a request.

If you really want to make a "singleton" eligible for garbage collection, you'd probably want to have a method to set the static variable to null (and hope that nothing else had taken a copy of the reference). Obviously the next time anyone asked for an instance, it would need to be recreated... at which point it's not really a singleton, of course.