测试题

一、选择题

1.Which four options describe the correct default values for array elements of the types indicated?(多选)
A. int -> 0
B. String -> "null"
C. Dog -> null
D. char -> '\u0000'
E. float -> 0.0f
F. boolean -> true

2.Which one of these lists contains only Java programming language keywords? （多选）
A.class, if, void, long, Int, continue
B.goto, instanceof, native, finally, default, throws
C.try, virtual, throw, final, volatile, transient
D.strictfp, constant, super, implements, do
E.byte, break, assert, switch, include

3、Which will legally declare, construct, and initialize an array?
A. int [] myList = {"1", "2", "3"};
B. int [] myList = (5, 8, 2);
C. int myList [] [] = {4,9,7,0};
D. int myList [] = {4, 3, 7};

4.Which is a reserved word in the Java programming language?
A. method
B. native
C. subclasses
D. reference
E. array

5、Which three are legal array declarations?（多选）
A.int [] myScores [];
B.char [] myChars;
C.int [6] myScores;
D.Dog myDogs [];
Dog myDogs [7];

6、

public interface Foo 
{ 
    int k = 4; /* Line 3 */
}

Which three piece of codes are equivalent to line 3?
A. final int k = 4;
B. public int k = 4;
C. static int k = 4;
D. abstract int k = 4;
E. volatile int k = 4;
F. protected int k = 4;

7、Which is the valid declarations within an interface definition?
A. public double methoda();
B. public final double methoda();
C. static void methoda(double d1);
D. protected void methoda(double d1);

8、Which one is a valid declaration of a boolean?
A. boolean b1 = 0;
B. boolean b2 = 'false';
C. boolean b3 = false;
D. boolean b4 = Boolean.false();
E. boolean b5 = no;

9、Which three are valid declarations of a float?（多选）
A.float f1 = -343;
B.float f2 = 3.14;
C.float f3 = 0x12345;
D.float f4 = 42e7;
E.float f5 = 2001.0D;
float f6 = 2.81F;

10、You want subclasses in any package to have access to members of a superclass. Which is the most restrictive access that accomplishes this objective?
A. public
B. private
C. protected
D. transient

11、

interface Base 
{
    boolean m1 ();
    byte m2(short s);
}

which two code fragments will compile? (多选)
A. interface Base2 implements Base {}
B. abstract class Class2 extends Base
{ public boolean m1(){ return true; }}
C. abstract class Class2 implements Base {}
D. abstract class Class2 implements Base
{ public boolean m1(){ return (7 > 4); }}
E. abstract class Class2 implements Base
{ protected boolean m1(){ return (5 > 7) }}

12、

public class Test { }

What is the prototype of the default constructor?
A. Test( )
B. Test(void)
C. public Test( )
D. public Test(void)

13、What is the most restrictive access modifier that will allow members of one class to have access to members of another class in the same package?
A. public
B. abstract
C. protected
D. synchronized
E. default access

14、Which of the following is/are legal method declarations?
A.protected abstract void m1();
B.static final void m1(){}
C.synchronized public final void m1() {}
D.private native void m1();

15、Which cause a compiler error?
A. int[ ] scores = {3, 5, 7};
B. int [ ][ ] scores = {2,7,6}, {9,3,45};
C. String cats[ ] = {"Fluffy", "Spot", "Zeus"};
D. boolean results[ ] = new boolean [] {true, false, true};
E. Integer results[ ] = {new Integer(3), new Integer(5), new Integer(8)};

16、

class A 
{  
    protected int method1(int a, int b) 
    {
        return 0; 
    } 
}

Which is valid in a class that extends class A?
A. public int method1(int a, int b) {return 0; }
B. private int method1(int a, int b) { return 0; }
C. public short method1(int a, int b) { return 0; }
D. static protected int method1(int a, int b) { return 0; }

17、Given a method in a protected class, what access modifier do you use to restrict access to that method to only the other members of the same class?
A. final
B. static
C. private
D. protected
E. volatile

18、

public class While /* Line 1 */
{
    public void loop() 
    {
        int x= 0;
        while ( 1 ) /* Line 6 */
        {
            System.out.print("value is " + (x + 1)); /* Line 8 */
        }
    }
}

Which statement is true?
A. There is a syntax error on line 1.
B. There are syntax errors on lines 1 and 6.
C. There are syntax errors on lines 1, 6, and 8.
D. There is a syntax error on line 6.

19、

public class Myfile 
{ 
    public static void main (String[] args) 
    {
        String a = args[1]; 
        String b = args[2]; 
        String c = args[3]; 
        System.out.print(c);
    } 
}

Select how you would start the program to cause it to print:2
A. java Myfile 222
B. java Myfile 1 2 2 3 4
C. java Myfile 1 3 2 2
D. java Myfile 0 1 2 3

20、
What will be the output of the program?

public class WrapTest 
{
    public static void main(String [] args) 
    {
        int result = 0;
        short s = 42;
        Long x = new Long("42");
        Long y = new Long(42);
        Short z = new Short("42");
        Short x2 = new Short(s);
        Integer y2 = new Integer("42");
        Integer z2 = new Integer(42);
        if (x == y) /* Line 13 */
            result = 1;
        if (x.equals(y) ) /* Line 15 */
            result = result + 10;
        if (x.equals(z) ) /* Line 17 */
            result = result + 100;
        if (x.equals(x2) ) /* Line 19 */
            result = result + 1000;
        if (x.equals(z2) ) /* Line 21 */
            result = result + 10000;
        System.out.println("result = " + result);
    }
}

A. result = 1
B. result = 10
C. result = 11
D. result = 11010

21、What will be the output of the program?

public class Test178 
{ 
    public static void main(String[] args) 
    {
        String s = "foo"; 
        Object o = (Object)s; 
        if (s.equals(o)) 
        { 
            System.out.print("AAA"); 
        } 
        else 
        {
            System.out.print("BBB"); 
        } 
        if (o.equals(s)) 
        {
            System.out.print("CCC"); 
        } 
        else 
        {
            System.out.print("DDD"); 
        } 
    } 
}

A. AAACCC
B. AAADDD
C. BBBCCC
D. BBBDDD

22、What will be the output of the program?

class A 
{ 
    public A(int x){} 
} 
class B extends A { } 
public class test 
{ 
    public static void main (String args []) 
    {
        A a = new B(); 
        System.out.println("complete"); 
    } 
}

A. It compiles and runs printing nothing
B. Compiles but fails at runtime
C. Compile Error
D. Prints "complete"

23、Jar文件Poker.jar中已正确定义了一个类games.cards.Poker。在linux系统中用户想用以下命令运行Poker中的main方法：
java games.cards.Poker
用户需要怎么做？

A. 把 Poker.jar 放在目录 /stuff/java中,并且设置 CLASSPATH 包含/stuff/java
B. 把 Poker.jar 放在目录 /stuff/java中,并且设置 CLASSPATH 包
含/stuff/java/.jar
C. 把 Poker.jar 放在目录 /stuff/java中,并且设置 CLASSPATH 包
含/stuff/java/Poker.jar
D. 把 Poker.jar 放在目录/stuff/java/games/cards中, 并且设置
CLASSPATH 包含 /stuff/java
E.把 Poker.jar 放在目录/stuff/java/games/cards中, 并且设置
CLASSPATH 包含/stuff/java/.jar
F. 把 Poker.jar 放在目录 /stuff/java/games/cards中, 并且设置
CLASSPATH 包含/stuff/java/Poker.jar

24、给定一个编译好的class，源代码如下：

 package com.sun.sjcp;
 public class Commander {
      public static void main(String[] args) {
          // more code here
      }
  }

假设class文件在 /foo/com/sun/sjcp/, 当前目录是 /foo/, classpath中已经包含了 "." (当前目录). 以下哪个命令能够正确运行Commander?
A. java Commander
B. java com.sun.sjcp.Commander
C. java com/sun/sjcp/Commander
D. java -cp com.sun.sjcp Commander
E. java -cp com/sun/sjcp Commander

25、Java的字符类型采用的是Unicode编码方案，每个Unicode码占用（ ）个比特位。
A、8
B、16
C、32
D、64

二、编程题
1、编写一个程序，从命令行终端输入一系列整数，整数之间以空格分隔。获取输入的整数，放到List中。然后对这些输入的数值求和，并输出。

2、编写一个函数，输入参数是一个字符串（是一个四则运算表达式，只有 + - 两种运算符，没有括号），输出是浮点数。函数实现的功能就是计算输入的四则运算表达式的值，并作为函数返回值返回。
要求不能使用第三方库来实现，而是自己写代码解析字符串进行运算。
举例：
输入 3+5-2 返回值为 6
输入 13-8-5+2 返回值为 2

3、假设一个学生成绩管理系统中有如下实体：
学生：包括但不限于 学号、姓名等信息
课程信息：课程编号、课程名等信息

有这样一个java接口

interface Manager{
   void selCourse(Student student, Course course);
   void delCourse(Student student, Course course);
   void showCourse(Student student);
}

上面代码中的Student 为建模后的学生类，Course 为课程信息类。
1）selCourse方法的功能是学生选课，如果输入的学生或课程不存在，则需要抛出一个自定义异常。
2）delCourse方法的功能是删除所选课程，如果输入的学生或课程不存在，则需要抛出一个自定义异常。
3）showCourse方法的功能是输出指定学生所选的课程，如果输入的学生不存在，则需要抛出一个自定义异常。

要求：
1、编写一个类（可以有额外的附加类），实现上面定义的Manager接口
2、学生信息和课程信息，在代码中写死，存放到数组中
3、学生的选课信息，存放到数组中

最后编辑于 ：
©著作权归作者所有,转载或内容合作请联系作者
【社区内容提示】社区部分内容疑似由AI辅助生成，浏览时请结合常识与多方信息审慎甄别。
平台声明：文章内容（如有图片或视频亦包括在内）由作者上传并发布，文章内容仅代表作者本人观点，简书系信息发布平台，仅提供信息存储服务。

相关阅读更多精彩内容

  • rljs
    rljs by sennchi Timeline of History Part One The Cognitiv...
    sennchi阅读 12,173评论 0赞 10
  • Spring Cloud
    Spring Cloud为开发人员提供了快速构建分布式系统中一些常见模式的工具（例如配置管理，服务发现，断路器，智...
    卡卡罗2017阅读 136,058评论 19赞 139
  • Java面试题全集（上）
    废话不多说，自己进入今天的主题 1、面向对象的特征有哪些方面？ 答：面向对象的特征主要有以下几个方面： - 抽象：...
    传奇内服号阅读 7,098评论 1赞 31
  • 2018-02-02
    这几天我们都在309梦想计划群里做自我介绍，我昨天也做了自我介绍。和大家对比起来，我分享的很是平淡，可是杨总和大家...
    林筱芬阅读 1,373评论 0赞 0
  • 区块链自媒体，要怎么写才有一席之地？
    区块链是一个崭新的行业，同样也是区块链自媒体的红利期！ 非常多小白（例如我）是刚听说炒币赚钱就冲进来了，他们有很多...
    哈叔变形季阅读 8,032评论 2赞 3

友情链接更多精彩内容