"Object" vs "Object Variable" in Java?

Question

I am teaching myself Java, and one of the review exercises in my book asks for the difference between an "object" and an "object variable."

I know what an object is (a specific instance of a class), but I can't seem to find the term "object variable" anywhere in the book (no answers section) or on the internet.

Does anyone know the meaning of this term?

Answer 1

I'll bite.

The Object is the instance itself, whereas the Object Variable is the reference to the Object.

Here's a contrived example:

Object o = new Object(); Object ref1 = o; 

In his case, there is a single instance of the Object, but it is referenced by two Object Variables: o and ref1.

When an Object is no longer referenced by an Object Variable, the Object is garbage collected.

Answer 2

It's a synonym of "instance variable":

class A {     static int m;  // <-- class variable     int n;         // <-- instance variable     ... } 

Evidently, this term is not so commonly used, and it would better to avoid any potential ambiguities by just sticking with "instance variable".