Which two demonstrate an “is a” relationship？ （）
A: public interface Person{} public class Employee extends Person{}
B: public interface Shape{} public class Employee extends Shape{}
C: public interface Color{} public class Employee extends Color{}
D: public class Species{} public class Animal （private Species species；）
E: interface Component{} Class Container implements Component （ Private Component[ ] children； ）
A: public interface Person{} public class Employee extends Person{}
B: public interface Shape{} public class Employee extends Shape{}
C: public interface Color{} public class Employee extends Color{}
D: public class Species{} public class Animal （private Species species；）
E: interface Component{} Class Container implements Component （ Private Component[ ] children； ）
举一反三
- import java.io.*; class Person{ public void print(){System.out.print("Person ");} public void printMyGender(String s){ this.print(); System.out.print(s+" "); } } class Gender{ String type="gender"; public void print(Person p){p.printMyGender(type);} } class Female extends Gender{ public Female(){ type="female"; } } class Male extends Gender{ public Male(){ type="male"; } } class Employee extends Person{ public void print(){ System.out.print("Employee ");} } class Manager extends Employee{ public void print(){ System.out.print("Manager ");} } public class Test{ public static void main(String[] args){ Manager man = new Manager(); Employee em = new Employee(); Gender gender1 = new Male(); Gender gender2 = new Female(); gender1.print(man); gender2.print(em); } } 对于以上代码，其运行结果是
- 有一段程序代码如下，以下哪个选项中的语句是正确的。 public interface A { } public class B implements A { } public class C extends B { }
- A类同时实现接口B和接口C，正确的写法是： A: public class A implements B, implements C {...} B: public class A implements B, C {...} C: public class A interface B, iinterface C {...} D: public class A extends B, C {...}
- Which two， inserted at line 11， will allow the code to compile？（） A: public class MinMax<？>{ B: public class MinMax<？ extends Number>{ C: public class MinMax<N extends Object>{ D: public class MinMax<N extends Number>{ E: public class MinMax<？ extends Object>{ F: public class MinMax<N extends Integer>{
- class Person{} class Student extends Person{ public int id; public int score; public String name; public int getScore() { return score; }