싱글톤(singleton) 클래스를 통해 생성할 수 있는 객체가 한개만 되도록 만드는 것 class Singleton { private static Singleton one; private Singleton() { } public static Singleton getInstance() { if(one ==null) { one = new Singleton(); } return one; } } public class Main { public static void main(String[] args) { Singleton singleton1 = Singleton.getInstance(); Singleton singleton2 = Singleton.getInstance(); System.out.println(si..