Why the singleton pattern used rather than static things?

Question

class Single
    private Single() {}
    private void print() { System.out.println("Foo~"); }
    private static Single one = new Single();
    public static void print() { one.print(); }
class Stat
    public static void print() { System.out.println("Foo~"); }
}What's the different?? What is the benefit of the singleton one?

Answer 1

There is no practical difference - because, in fact, that is not the singleton pattern!
A singleton would look like:
class Singleton {
    private Singleton() {}
    public void print() { System.out.println("Foo~"); }
    private static Singleton instance = new Singleton();
    public static Singleton getInstance() { return instance; }
}The benefit of this pattern is, that your client code doesn't have to know that there is only one instance (getInstance could return another instance for every call) or of which actual type it is (getInstance could return an instance of any Subclass of Singleton).
See http://c2.com/cgi/wiki?SingletonPattern for more information on the pattern.