单选题What is the output of the following code? ( )Public class Test {Pu

1. 单选题What is the output of the following code? ( )Public class Test {Public static void main(String] args) {New Person().printPerson();New Student().printPerson();}}Class Student extends Person {@OverridePublic String getInfo() {Return "Student";}}Class Person {Public String getInfo() {Return "Person";}Public void printPerson() {System.out.println(getInfo());}} 选项： A:Person Person B:Person Student C:Stduent Student D:Student Person

2.下列代码的输出是什么public class Test { public static void main(String[] args) { new Person().printPerson(); new Student().printPerson(); }} class Student extends Person { private String getInfo() { return "Student"; }} class Person { private String getInfo() { return "Person"; } public void printPerson() { System.out.println(getInfo()); }}选项： A:Person Person; B:Person Student; C:Stduent Student; D:Student Person

3.下列代码的输出是什么?public class Test { public static void main(String[] args) { new Person().printPerson(); new Student().printPerson(); }} class Student extends Person { public String getInfo() { return "Student"; }} class Person { public String getInfo() { return "Person"; } public void printPerson() { System.out.println(getInfo()); }}选项： A:Person Person; B:Person Student; C:Stduent Student; D:Student Person

4.下面代码的运行结果是（）Public class Test { public static void main(String] args) { new Person().printPerson(); new Student().printPerson(); }}Class Student extends Person { @Override public String getInfo() { return "Student"; }}Class Person { public String getInfo() { return "Person"; } public void printPerson() { System.out.println(getInfo()); }} 选项： A: Person Person B: Person Student C: Stduent Student D: Student Person

5.18() Given the following code, find the compile error?Public class Test {Public static void main(String] args) {M(new GraduateStudent());M(new Student());M(new Person());M(new Object());}Public static void m(Student x) {System.out.println(x.toString());}}Class GraduateStudent extends Student {}Class Student extends Person {Public String toString() { return "Student";}}Class Person extends Object {Public String toString() {Return "Person";}} 选项： A: m(new GraduateStudent()) causes an error B: m(new Student()) causes an error C: m(new Person()) causes an error D: m(new Object()) causes an error

6.下列语句输出的结果是________。class Person: def getInfo(self): return "Person" def printPerson(self): print(self.getInfo())class Student(Person): def getInfo(self): return "Student"Person().printPerson()Student().printPerson()选项： A:PersonStudent; B:PersonPerson; C:StudentStudent; D:StudentPerson

7.阅读下列程序，并给出程序运行的结果。Public class PolymorphismDemo {Public static void main(String] args) { m(new GraduateStudent()); m(new Student()); m(new Person());} Public static void m(Object x) {System.out.println(x.toString());}} Class GraduateStudent extends Student {} Class Student extends Person {Public String toString() { return "I am a student";}} Class Person extends Object {Public String toString() { return "I am a person";}}

8.下列语句输出的结果是________。class Person: def __getInfo(self): return "Person" def printPerson(self): print(self.__getInfo())class Student(Person): def __getInfo(self): return "Student"Person().printPerson()Student().printPerson()选项： A:PersonPerson; B:PersonStudent; C:StudentStudent; D:StudentPerson

9. 多选题Given the following code, find the compile error. ( )Public class Test {Public static void main(String] args) {M(new GraduateStudent());M(new Student());M(new Person());M(new Object());}Public static void m(Student x) {System.out.println(x.toString());}}Class GraduateStudent extends Student {}Class Student extends Person {@OverridePublic String toString() {Return "Student";}}Class Person extends Object {@OverridePublic String toString() {Return "Person";}} 选项： A:m(new GraduateStudent()) causes an error B:m(new Student()) causes an error C:m(new Person()) causes an error D:m(new Object()) causes an error

10.找出下面代码中存在的错误。public class Test { public static void main(String[] args) { m(new GraduateStudent()); m(new Student()); m(new Person()); m(new Object()); } public static void m(Student x) { System.out.println(x.toString()); }}class GraduateStudent extends Student {}class Student extends Person { @Override public String toString() { return "Student"; }}class Person extends Object { @Override public String toString() { return "Person"; }} 选项：A、m(new GraduateStudent()),产生错误 B、m(new Student()) ,产生错误 C、m(new Person()) ,产生错误 D、m(new Object()) ,产生错误

11.分析下列代码，找出编译错误。 public class Test { public static void main(String[ ] args) { m(new GraduateStudent()); m(new Student()); m(new Person()); } public static void m(Student x) { System.out.println(x.toString()); } } class GraduateStudent extends Student { } class Student extends Person { public String toString() { return "Student"; } } class Person extends Object { public String toString() { return "Person"; } } 选项： A、m(new Student()) 会导致编译错误 B、m(new Person()) 会导致编译错误 C、以下都不对 D、m(new GraduateStudent()) 会导致编译错误

12.编译运行如下java代码，输出结果是（） class Person{ String name = "person"; public void shout(){ System.out.print(name); } } class Student extends Person{ String name = "student"; String school = "school"; } public class Test{ public static void main(String[] args){ Person p = new Student(); p.shout(); } } 选项： A、person B、student C、person student D、编译错误

13.找出下面代码的编译错误Public class Test { public static void main(String] args) { m(new GraduateStudent()); m(new Student()); m(new Person()); m(new Object()); } public static void m(Student x) { System.out.println(x.toString()); }}Class GraduateStudent extends Student {}Class Student extends Person { @Override public String toString() { return "Student"; }}Class Person extends Object { @Override public String toString() { return "Person"; }} 选项： A: m(new GraduateStudent())导致一个错误 B: m(new Student())导致一个错误 C: m(new Person()) 导致一个错误 D: m(new Object()) 导致一个错误

14.编译运行如下代码，输出结果是（）。Class Person {String name=”person”;public void shout(){System.out.prinnt(name);}}Class Student extends person{String name=”student”;Student school=”school”;}Class Text {public static void main(String [] args){Person p=new Student();p.shout();}} 选项： A、person B、student C、person D、编译错误

15.下面代码的输出结果是。 public class DynamicBindingDemo { public static void main(String[] args) { m(new GraduateStudent()); m(new Student()); m(new Person()); m(new Object()); } public static void m(Object x) { System.out.println(x.toString()); } } class GraduateStudent extends Student { } class Student extends Person { public String toString() { return "Student"; } } class Person extends Object { public String toString() { return "Person"; } } 备注：输出结果的最后一行，大家如下填写：java.lang.Object@XXXXXX

16.以下程序的输出结果是？class Person{String name="person";public void shout(){System.out.print(name);}}class Student extends Person{String name="student";String school="school";}class Test{public static void main(String[] args){Person p=new Student();System.out.print(p instanceof Student);System.out.print(p instanceof Person);System.out.print(p instanceof Object);System.out.print(p instanceof System);}}

(s); } }public class Person{ public int ID { get; set; } public string Name { get; set; } public static void PromptName(T t) where T : Person { Console.WriteLine(t); } }程序运行结果">17.阅读下面程序段class Student : Person{ public override string ToString() { return ID + "\t" + Name; } static void Main() { Student s = new Student(); s.ID = 1; s.Name = "JSON"; PromptName(s); } }public class Person{ public int ID { get; set; } public string Name { get; set; } public static void PromptName(T t) where T : Person { Console.WriteLine(t); } }程序运行结果

18.【填空题】23. import java.text.*; public class Java_2 { public static void main(String[] args) { Person[] people = new Person[2]; people[0] = new Worker("老张", 30000); people[1] = new Student("小王", "计算机科学"); for (int i = 0; i < people.length; i++) { Person p = people[i]; //*********Found********** System.out.println(____________________() + ", " + p.getDescription()); } } } //*********Found********** ________________ class Person { public Person(String n) { name = n; } //*********Found********** public ___________________ String getDescription(); public String getName() { return name; } private String name; } //*********Found********** class Worker _________________ Person { public Worker(String n, double s) { super(n); salary = s; } public String getDescription() { NumberFormat formatter = NumberFormat.getCurrencyInstance(); return "工人，年薪是 " + formatter.format(salary) + "。"; } private double salary; } //*********Found********** class Student _________________ Person { public Student(String n, String m) { super(n); major = m; } public String getDescription() { return "学生，专业是 " + major + "。"; } private String major; }

19.class Person{} class Student extends Person{ public int id; public int score; public String name; public int getScore() { return score; }

20.根据以下程序可以判断选项（）没有语法错误。public class Person{ public Person(int id, String name)throws Exception{}}class MyException extends Exception{}选项： A:public class Test{public static void main(String[] args){System.out.println(new Person(20, “John”));}} B:public class Test{public static void main(String[] args){System.out.println(new Person(20, “John”).toString());}} C:public class Test{public static void main(String[] args)throws Exception{System.out.println(new Person(20, “John”).toString());}} D:public class Test{public static void main(String[] args)throws MyException{System.out.println(new Person(20, “John”).toString());}}