Overview and features of the 4.9 private keyword

/*private: is a permission modifier that modifies member variables and member methods that are decorated by members that can only be accessed in this class */class Demo {//int num = 10;//with private private int num = 10;public void Show () {System.out.println (num);} private void Method () {System.out.println ("method");} public void function () {method ();}} Class Privatedemo {public static void main (string[] args) {Demo d = new Demo ();//cannot method private member variable//SYSTEM.OUT.PRINTLN (D.num); D.show ();//cannot access private member methods//D.method ();d. function ();}}

/* Package and Private application: A: Use the member variable with private modifier B: Improve the corresponding getxxx () and Setxxx () methods *///define student class class student {//  name private  String name;//  Age private int age;//  Name get value Public string getname ()  {return name;}   Name setting value Public void setname (String n)  {name = n;}   Age gain Value public int getage ()  {return age;}   Age Assignment Public void setage (int a)  {age = a;}}   Test class Class studenttest {public static void main (String[] args)  {//   Create student Object Student s = new student ();//  use member variable//  error: Private decoration, the outside world can not directly access the//  System.out.println (s.name+ "---" +s.age); System.out.println (S.getname ()  +  "---"  + s.getage ());//  assign a value to a member variable// s.name =   "Brigitte";// s.age = 27;//  assigns S.setname ("Brigitte") by means of the method; S.setage (27); System.out.println (S.getname ()  +  "---"  + s.getage ());}}

Overview and features of the 4.9 private keyword