java考试选择题英文版

2021年2月1日发(作者：资金缺口)

Read the questions carefully

I have tried to make the questions unambiguous (the meaning should be obvious), but make sure

you have read what I have written not what you think I might have written. Thus if it says

can

be

declared

with

the

private

modifier

it

means

It

is

possible

to

declare

a

class

with

the

private modifier and not that all classes in all situations can be declared as private. Each question

may have one or more correct Answers.

Questions

Question 1)

Which of the following lines will compile without warning or error.

1) float f=1.3;

2) char c=

3) byte b=257;

4) boolean b=null;

5) int i=10;

Question 2)

What will happen if you try to compile and run the following code

public class MyClass {

public static void main(String arguments[]) {

amethod(arguments);

}

public void amethod(String[] arguments) {

n(arguments);

n(arguments[1]);

}

}

1) error Can't make static reference to void amethod.

2) error method main not correct

3) error array must include parameter

4) amethod must be declared with String

Because main is defined as static you need to create an instance of the class in

order to call any non-static methods.

------------------- -------------------------------------------------- -----------

Question 3)

Which of the following will compile without error

要先出现

package

1) import .*;

package Mypackage;

class Myclass {}

2) package MyPackage;

import .*

;

class MyClass{}

3) /*This is a comment */

package MyPackage;

import .*;

class MyClass{}

---------------------------------------------- ----------------------------------

Question 4)

A byte can be of what size

1) -128 to 127

2) (-2 power 8 )-1 to 2 power 8

3) -255 to 256

4)depends on the particular implementation of the Java Virtual machine

------- -------------------------------------------------- -----------------------

Question 5)

What will be printed out if this code is run with the following command line?

Java

myprog

good

morning;

public class myprog{

public static void main(String argv[])

{

n(argv[2]);

}

}

1) myprog

2) good

3) morning

4) Exception raised:

--------------------------- -------------------------------------------------- ---

Question 6)

Which of the following are keywords or reserved

（

预定义

）

words in Java?

1) if

2) then

3) goto

4) while

5) case

------------------------------------------------- -------------------------------

Question 7)

Which of the following are legal identifiers(

标识符

)

1) 2variable

2) variable2

3) _whatavariable

4) _3_

5) $$anothervar

6) #myvar

< p>
-------------------------------------------- ------------------------------------

Question 8)

What will happen when you compile and run the following code?

public class MyClass{

static int i;

public static void main(String argv[]){

n(i);

}

}

局部变量（在函数内部）必须先初始化，类级别的可以不初始化

Class level variables are always initialised to default values. In the case of an

int this will be 0. Method level variables are not given default values and if you

attempt to use one before it has been initialised it will cause the

Error Variable i may not have been initialized

1) Error Variable i may not have been initialized

2) null

3) 1

4) 0

------------------------------------------------- -------------------------------

Question 9)

What will happen if you try to compile and run the following code?

public class Q {

public static void main(String argv[]){

int anar[]=new int[]{1,2,3};

n(anar[1]);

}

}

1) 1

2) Error anar is referenced before it is initialized

3) 2

4) Error: size of array must be defined

--------------- -------------------------------------------------- ---------------

Question 10)

What will happen if you try to compile and run the following code?

public class Q {

public static void main(String argv[]){

int anar[]=new int[5];

n(anar[0]);

}

}

1) Error: anar is referenced before it is initialized

2) null

3) 0

4) 5

--------------------------- -------------------------------------------------- ---

Question 11)

What will be the result of attempting to compile and run the following code?

abstract class MineBase {

abstract void amethod();

static int i;

}

public class Mine extends MineBase {

public static void main(String argv[]){

int[] ar=new int[5];

for(i=0;i < i++)

n(ar[i]);

}

}

Any class derived from an abstract class must either define all of the abstract

methods or be declared abstract itself.

1) a sequence of 5 0's will be printed

2) Error: ar is used before it is initialized

3) Error Mine must be declared abstract

4) IndexOutOfBoundes Error

--------------------------- -------------------------------------------------- ---

Question 12)

What will be printed out if you attempt to compile and run the following code ?

int i=1;

switch (i) {

case 0: n(

break;

case 1: n(

case 2: n(

default: n(

}

1) one

2) one, default

3) one, two, default

4) default

--------------- -------------------------------------------------- ---------------

Question 13)

What will be printed out if you attempt to compile and run the following code?

int i=9;

switch (i) {

default: n(

case 0: n(

break;

case 1: n(

case 2: n(

}

1) default

2) default, zero

3) error default clause not defined

4) no output displayed

----- -------------------------------------------------- -------------------------

Question 14)

Which of the following lines of code will compile without error

1) int i=0;

if(i) {

n(

}

2) boolean b=true;

boolean b2=true;

if(b==b2) {

n(

}

3) int i=1;

int j=2;

if(i==1|| j==2) n(

4) int i=1;

int j=2;i

f(i==1 &| j==2) n(

------------------- -------------------------------------------------- -----------

Question 15)

What will be output if you try to compile and run the following code, but there is

no file called in the current directory?.

import .*;

public class Mine {

public static void main(String argv[]){

Mine m=new Mine();

n(d());

}

public int amethod() {

try {

FileInputStream dis=new FileInputStream(

}catch (FileNotFoundException fne) {

n(

return -1;

}catch(IOException ioe) {

}

finally{

n(

}

return 0;

}

}

1) No such file found

2 No such file found ,-1

3) No such file found, Doing finally, -1

4) 0

--------------------------- -------------------------------------------------- ---

Question 16)

Which of the following statements are true?

1) Methods cannot be overriden to be more private

2) static methods cannot be overloaded

Static methods cannot be overriden but they can be overloaded

3) private methods cannot be overloaded

4) An overloaded method cannot throw exceptions not checked in the base class

--------------------------------------- -----------------------------------------

Question 17)

What will happen if you attempt to compile and run the following code?

class Base {}

class Sub extends Base {}

class Sub2 extends Base {}

public class CEx{

public static void main(String argv[]){

Base b=new Base();

Sub s=(Sub) b;

}

}

1) Compile and run without error

2) Compile time Exception

3) Runtime Exception

--------------------------- -------------------------------------------------- ---

Question 18)

Which of the following statements are true?

1) n( -1 >>> 2);will output a result larger than 10

无符号右移

2) n( -1 >> 2); will output a positive number

输出

-1

3) n( 2 >> 1); will output the number 1

4) n( 1 <<< 2); will output the number 4

< p>
-------------------------------------------- ------------------------------------

Question 19)

What will happen when you attempt to compile and run the following code?

public class Tux extends Thread{

static String sName =

public static void main(String argv[]){

Tux t = new Tux();

(sName);

n(sName);

}

public void piggy(String sName){

sName = sName +

start();

}

public void run(){

for(int i=0;i

<

4; i++){

sName = sName +

}

}

}

1) Compile time error

2) Compilation and output of

3) Compilation and output of

4)

Compilation

and

output

of

either

0

0

1

---- -------------------------------------------------- --------------------------

Question 20)

What will be displayed when you attempt to compile and run the following code

//Code start

import .*;

public class Butt extends Frame{

public static void main(String argv[]){

Butt MyBut=new Butt();

}

Butt(){

Button HelloBut=new Button(

Button ByeBut=new Button(

add(HelloBut);

add(ByeBut);

setSize(300,300);

setVisible(true);

}}//Code end

1) Two buttons side by side occupying all of the frame, Hello on the left and Bye on

the right

2) One button occupying the entire frame saying Hello

3) One button occupying the entire frame saying Bye

4) Two buttons at the top of the frame one saying Hello the other saying Bye

--------------- -------------------------------------------------- ---------------

Question 21)

What will be output by the following code?

public class MyFor{

public static void main(String argv[]){

int i;

int j;

outer:

for (i=1;i <3;i++)

inner:

for(j=1; j<3; j++) {

if (j==2)

continue outer;

n(

}

}

}

1) Value for i=1 Value for j=1

2) Value for i=2 Value for j=1

3) Value for i=2 Value for j=2

4) Value for i=3 Value for j=1

< br>----------------------------------------------- ---------------------------------

Question 22)

Which statement is true of the following code?

public class Agg{

public static void main(String argv[]){

Agg a = new Agg();

();

}

public void go(){

DSRoss ds1 = new DSRoss(

();

}

}

class DSRoss extends Thread{

private String sTname=

DSRoss(String s){

sTname = s;

}

public void run(){

notwait();

n(

}public void notwait(){

while(true){

try{

n(

wait();

}catch(InterruptedException ie){}

n(sTname);

notifyAll();

}

}

}

1) It will cause a compile time error

2) Compilation and output of

3) Compilation and output of

4) Runtime error, an exception will be thrown

-------------------- -------------------------------------------------- ----------

Question 23)

Which of the following methods can be legally inserted in place of the comment //Method Here ?

class Base{

public void amethod(int i) { }

}

public class Scope extends Base{

public static void main(String argv[]){ }

//Method Here}

1) void amethod(int i) throws Exception {}

2) void amethod(long i)throws Exception {}

3) void amethod(long i){}

4) public void amethod(int i) throws Exception {}

--------------------------- -------------------------------------------------- ---

Question 24)

Which of the following will output -4.0

1) n((-4.7));

2) n((-4.7));

3) n((-4.7));

4) n((-4.7));

Options

1

and

2

will

produce

-5

and

option

4

will

not

compile

because

the

min

method

requires 2 parameters.

--------------------------- -------------------------------------------------- ---

Question 25)

What will happen if you attempt to compile and run the following code?

Integer ten=new Integer(10);

Long nine=new Long (9);

n(ten + nine);

int i=1;

n(i + ten);

1) 19 followed by 20

2) 19 followed by 11

3) Compile time error

4) 10 followed by 1

--------------- -------------------------------------------------- ---------------

Question 26)

If you run the code below, what gets printed out?

String s=new String(

int iBegin=1;

char iEnd=3;

n(ing(iBegin,iEnd));

1) Bic