Access rights - private, public, protected

Instance methods in a class can always operate instance variables and class variables in that class , Class methods can always operate on class variables in this class , This has nothing to do with access restrictions .

One ：private—— Private variables and private methods

Private variables and private methods Only valid in the current class , If an object of this class is created in another class , Then the object cannot access its own private variables and call private methods .

Two ：public—— Common variables and common methods

Create an object of another class in one class , This object can manipulate common variables and common methods in its class .

3、 ... and ：protected—— Protected member variables and methods

When using a class in another class Andy After creating an object , If this class and class Andy In the same package , Then the object can access protected Variables and protected Method .

Four ： Friendly variables and friendly methods

When using a class in another class Andy After creating an object , If this class and class Andy In the same package , Then the object can access friendly variables and friendly methods in its own class .

If you use import Statement introduces another class in the package , And create an object with this class , Then the object of this class cannot access its own friendly variables and friendly methods .

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ps:

Out-of-service protected and private decorator .

Access restriction modifiers are arranged in order of access rights from high to low ：public、protected、 Amicable 、private.