🚀 go-pugleaf

hi ppl,
ive got a problem at hand at the moment that i want to limit the number of
objects that a class creates,  i know that this is possible in C++ like
this.... also possible in smalltalk

class Singleton
{
    public:
        static Singleton * Instance ();
    protected:
        Singleton ();
    private:
        static Singleton* _instance;

};

Singleton * Singleton::_instance = 0;

Singleton* Singleton::Instance ()
{
    if (_instance == 0)
    {
        _instance = new Singleton;
    }
    return _instance;
}

P.S. this example is from Design & Patrens by E. Gamma, R. Helm, R. Johnson
& J. Vlissides

but this dosent seem to work with java....
dose any1 have any idea how to achieve this in java....
thanx in advance
regards
Oaq