单例最简单的应用：

public class Car
{
	private static Car car=new Car();
	public static Car getInstance()
	{
		return car;
	}
	public static void main(String args[])
	{
		Car car1=getInstance();
		Car car2=getInstance();
		if(car1==car2)
		{
			System.out.println("same");
		}
	}
}