The cause of Cushing's syndrome boils down to: Your body is exposed to too much cortisol. There are a few ways that this over-exposure can happen, including taking certain medications and having a tumor on your pituitary gland or adrenal gland.
Difference between class and instance variables. Now, it should be clear what the difference between instance and class variables is. Class variables only have one copy that is shared by all the different objects of a class, whereas every object has itâs own personal copy of an instance variable. So, instance variables across different objects can have different values whereas class variables across different objects can have only one value.
1 Class methods can access class variables and class methods directly. 2  Class methods cannot access instance variables or instance methods directlythey must use an object reference. 3  Also, class methods cannot use the this keyword as there is no instance for this to refer to.hey are associated with the class, rather than with any object. Every instance of the class shares a class variable, which is in one fixed location in memory. Any object can change the value of a class variable, but class variables can also be manipulated without creating an instance of the class.