说出下面程序的执行结果: interface InterfaceA { （public abstract）String S = "good "; void f(); } abstract class ClassA { abstract void g(); } class ClassB extends ClassA implements InterfaceA { void g() { System.out.println(S); } public void f() { System.out.print( S); } } public class Test { public static void main(String[] args) { ClassA a = new ClassB(); InterfaceA b = new ClassB(); a.g(); System.out.println("-----"); b.f(); } }