Java – Package and Access

• example of common package
  • 
• use class in package
  • import package
    • then use class inside that package
  • or
  • packagePath packageClassObject = new packagePath
    • exp. java.util.Scanner in = new java.util.Scanner(System.in);
  • never need to import java.lang(default package)
  • do not need to import class in same package
• package name
  • recommend use domain name
  • can used to avoid name clash between class
  • should be unambiguous
• uasge of Class A and B
  • A and B same package
    • B can create a A object
      • protected and non-mentioned type can use and modify
      • not to private type
  • A and B different package, B extend A
    • B can create a A object
      • B can use extended protected and new b protected
      • not to a and b `s private and non-mentionmed