java preogram output

public class IfElse{
    public static void main(String argv[]){

        IfElse ie = new IfElse();
        ie.go(argv);

    }
    public void go(String[] sa){
    if(sa.length ==0){
        System.out.println("No parameter supplied");
    }else{
        String s = sa[0];
        if(s.equals("true")){
        System.out.println("OK");
        }else if(s.equals("false")){
        System.out.println("Not OK");
        }else{
        System.out.println("Invalid command parameter");
        }
    }

    }
}


I was trying above example from link
http://www.jchq.net/certkey/0201certkey.htm

I was trying to get output 'OK' but could not get it. What change I have to make to output 'OK'. Please advise. Any links, ideas, resources,sample code highly appreciated. thanks in advance.