需要帮助了解未引用的对象

Question

I was learning about objects on the Java Oracle tutorials and I learned how to reference an objects fields. They gave me two ways to do it, and the the first method I understood. However, the second method of doing it confused me. This is the code:

int height = new Rectangle().height;

I understand the statement itself, but it is what the tutorial says that confused me. The tutorial said "This statement creates a new Rectangle object and immediately gets its height. In essence, the statement calculates the default height of a Rectangle. Note that after this statement has been executed, the program no longer has a reference to the created Rectangle, because the program never stored the reference anywhere. The object is unreferenced, and its resources are free to be recycled by the Java Virtual Machine. But wait wasn't it referenced with the variable name "height"? So how is it unreferenced? I understand this:

Rectangle rect1 = new Rectangle(1,2,3);// random arguements don't mind them

So what makes this line of code referenced but the other unreferenced?

Answer 1

I think you are trying to read it too literally.

But wait wasn't it referenced with the variable name "height"? So how is it unreferenced?

You could say that an anonymous reference was created and well... referenced once to get the height.

Note that after this statement has been executed, the program no longer has a reference to the created Rectangle, because the program never stored the reference anywhere. The object is unreferenced, and its resources are free to be recycled by the Java Virtual Machine.

Since the reference is anonymous it cannot be used anywhere else. Hence after that statement there is no way to reference the object. If so then why keep it in memory - it may as well be garbage collected.