#227 – Instances of Classes Are Created on the Heap

Because they are reference types, instances of classes are stored on the heap.  When you instantiate (or create) an instance of a class, the actual object is created on the heap and you reference the newly created object with a variable whose type corresponds to the class’ type.  The variable that references the object is stored on the stack.

            // New Person object created on the heap
            // p variable is a stack-based reference to the new object
            Person p = new Person("Cary", "Grant");

Because a class object is created on the heap, you don’t destroy the object explicitly, but it is automatically garbage collected.  The object will be a candidate for garbage collection when there are no longer any variables that reference the object.

            p = new Person("Jimmy", "Stewart");

            // No variable references Cary Grant anymore,
            // so he can be garbage-collected.