Singleton in Java

package singleton;

class Printer {

    private static Printer instance;

    private Printer() {}

    public static Printer getInstance() {
        if (instance == null) {
            instance = new Printer();
        }
        return instance;
    }

    public void connect() {
        System.out.println("Do something here");
    }

}

public class Singleton {

    public static void main(String[] args) {
        Printer.getInstance().connect();
    }

}