IT의 신

Given class Base{ public void test() { System.out.println("Base "); } } class DerivedA extends Base{ public void test() { System.out.println("DerivedA "); } } class DerivedB extends DerivedA { public void test() { System.out.println("DerivedB "); } public static void main(String[] args) { Base b1=new DerivedB(); Base b2=new DerivedA(); Base b3=new DerivedB(); b1=(Base)b3; Base b4=(DerivedA)b3; b..