Class Member Access Control Modifiers : Access Control « Class Definition « Java Tutorial

Class members (methods, fields, constructors, etc) can have one of four access control levels:

  1. public,
  2. protected,
  3. private, and
  4. default access.
Access Level    From classes in other packages     From classes in the same package   From child classes   From the same class

public          yes                                yes                                yes                  yes

protected       no                                 yes                                yes                  yes

default         no                                 yes                                no                   yes

private         no                                 no                                 no                   yes

The default access is sometimes called package private.

Access levels to constructors are the same as those for fields and methods.

5.25.Access Control
5.25.1.Access Control: four access control modifiers
5.25.2.Class Access Control Modifiers
5.25.3.Using Access Attributes
5.25.4.Class Member Access Matrix
5.25.5.Specifying Access Attributes
5.25.6.The public Book class
5.25.7.Default access level
5.25.8.Class Member Access Control Modifiers
5.25.9.Composition with public objects
5.25.10.The protected keyword
5.25.11.Private Override
5.25.12.Understand the effects of public and private access
5.25.13.In a class hierarchy, private members remain private to their class.
5.25.14.A Superclass Variable Can Reference a Subclass Object
5.25.15.Create a Singleton Object