Java single case and multiple cases

The function of a singleton is to control how the class is generated, without letting the outer class arbitrarily new objects

1.car.java

Import Java.util.arraylist;import Java.util.list;public class Car {//privatized constructor to prevent the external class Newprivate Car () {}private static Car car = new car ();//single private static list<car> cars = new arraylist<car> ();//multiple examples, similar to connection pool public static car Getin Stance () {return car;} public void Run () {System.out.println ("Car running ......");}}

　　

2.test.java

public class Test {@org. junit.testpublic void Test () {Car car = car.getinstance (); Car.run (); Car car2 = Car.getinstance (); System.out.println (car = = CAR2); System.out.println (Car.equals (CAR2));}}

　　

Operation Result:

Java single case and multiple cases