The Member Variable in java is GC root it？

Question

I see a lot of explain about what is gc root.And i know local variable and params is gc root.But member variable is not gc root? If i type code in class body

    Person p = new Person("Lily");
    public void sayHello(){
        System.out.println(p.name);
    }

So,p is not local var but member var.If p is not GC root,it may be collection.And will have null point exception in sayHello method.

Answer 1

Person p will be root object. It would be hierarchical like:

person
  |
name

Also it wont end up in null pointer exception, as you initialized p and then you are trying to access name on it.

Nullpointer will only hit, if you defined p as null like Person p = null

And now you try to access name on it System.out.println(p.name);