Object Destruction in Java

Question

From the below example, In Case 1 the object is created in Class level and in Case 2 its created in Method level.

My understanding that in Case 2 once the method completes its execution the object is removed from heap memory . Is my understanding correct ?

Now My question is,in both the cases when will the object be removed from the Heap memory and which is efficient way of using in different context ?

public class A()
    {
        ClassB obj = new ClassB(); // Case 1
        private void method()
        {
            ClassB obj = new ClassB(); // Case 2
        }

    }

Answer 1

Might depend on your Java VM implementation, but generally GC is run only after the heap is filled / saturated. So no, most probably it won't be removed immediately.

Answer 2

In Your program. you have written only one line in which only declaration and initialization done. and one more thing i want to ask that is it class , Method or constructor .

private example(){ //what is example ?? Is it class or method or constructor ?
      ClassA obj = new ClassA();
    }

but i want to tell you ClassA obj will be eligible for gc after the } (Closing Paranthesis) execution done. but it is totally depends upon the jvm that when gc will be executed then collect and destroy the object.