What are access modifiers?

Modifier	Used with	Description
public	Outer classes, interfaces, constructors, Inner classes, methods and field variables	A class or interface may be accessed from outside the package. Constructors, inner classes, methods and field variables may be accessed wherever their class is accessed.
protected	Constructors, inner classes, methods, and field variables.	Accessed by other classes in the same package or any subclasses of the class in which they are referred (i.e. same package or different package).
private	Constructors, inner classes, methods and field variables,	Accessed only within the class in which they are declared
No modifier : (Package by default).	Outer classes, inner classes, interfaces, constructors, methods, and field variables	Accessed only from within the package in which they are declared.