Access Control

• Package

  • A collection of similar classes, interfaces, or other packages
  • package, import
  • Create a library and import it
    • Extract the package to .jar (Java ARchive) file in the project structure
    • Import the .jar file into the new project libraries in the project structure

• Scope

• Naming Convention

  • Reversed url

• Access control

  • At the top level: public or package-private (no explicit modifiers)

  • At the member level: public, private, protected, or package-private

  • A class declared with public is visible to all classes everywhere; A class with no modifier is visible only within its package

  • Modifier	Class	Package	Subclass outside the package	World
    public	Y	Y	Y	Y
    protected	Y	Y	Y	N
    no modifier	Y	Y	N	N
    private	Y	N	N	N