Variables in Java

Java Programming languages defines four flavors of variables:

  1. Instance variables (also known as non-static variables). They are declared inside a Java class, but outside of the scope of a method. Their values are unique to each instance (object) of the class.
  2. Class variable (also known as static variables). It can be said that a class variable is an instance variable declared with static keyword. Regardless how many object of the class has been instantiated, they share the same value for a class variable.
  3. Local variables. This are variables defined within the scope of a method. Such variables are defined only to the method within they are declared (i.e are not accessible from the rest of the class).
  4. Method variables (or simple parameters).

NOTE : Instance variables and class variable are sometimes called fields.

Take away 1 : Each object has its own copy of the instance variable.

Take away 2 : All objects share the same value for the class variable.

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