33_StaticKeyword

// static = modifier, A single copy of a variable/method is created and shared,
// The class "owns" the static member

<Main.java>
public class Main {
   public static void main(String[] args){
      Friend friend1 = new Friend("Spongebob");
      Friend friend2 = new Friend("Patrick");
      Friend friend3 = new Friend("Squidward");
      Friend friend4 = new Friend("Sandy");
      Friend.displayFriends();//use static method
      
      //System.out.println(Friend.numberOfFriends); //No longer need as used static void displayFriend()
   }
}

/* friend1 & friend2 & friend3 sharing same numberOfFriends variable bcoz class itself own the static member
* if remove "static" from "static int", not share same, numberOfFriends = 1 for each friend1, friend2, friend3
*/

<Friend.java>
public class Friend {
    String name;
    static int numberOfFriends;
    Friend(String name){
        this.name = name;
        numberOfFriends++;
    }
    static void displayFriends(){
        System.out.println("You have "+numberOfFriends+" friends");
    }
}