Java认证模拟题及分析(3)
添加时间: 2007-9-23 1:47:05 作者: JAVA题库 阅读次数:224 来源: http://www.d9soft.com
Question 29)
What is the result of the following operation?
System.out.println(4 3);
1) 6
2) 0
3) 1
4) 7
Answer to Question 29
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Question 30)
public class MyClass1 {
public static void main(String argv[]){ }
/*Modifier at XX */ class MyInner {}
}
What modifiers would be legal at XX in the above code?
1) public
2) private
3) static
4) friend
Answer to Question 30
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Question 31)
What will happen when you attempt to compile and run the following code?
public class Holt extends Thread{
private String sThreadName;
public static void main(String argv[]){
Holt h = new Holt();
h.go();
}
Holt(){}
Holt(String s){
sThreadName = s;
}
public String getThreadName(){
return sThreadName;
}
public void go(){
Holt first = new Holt("first");
first.start();
Holt second = new Holt("second");
second.start();
}
public void start(){
for(int i = 0; i < 2; i ++){
System.out.println(getThreadName() +i);
try{
Thread.sleep(100);
} catch(InterruptedException e){System.out.println(e.getMessage());}
}
}
}
1) Compile time error
2) Output of first0, second0, first0, second1
3) Output of first0, first1, second0, second1
4) Runtime error
Answer to Question 31
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Question 32)
An Applet has its Layout Manager set to the default of FlowLayout. What code would be correct to change to another Layout Manager.
1) setLayoutManager(new GridLayout());
2) setLayout(new GridLayout(2,2));
3) setGridLayout(2,2);
4) setBorderLayout();
Answer to Question 32
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Question 33)
What will happen when you attempt to compile and run the following code?.
class Background implements Runnable{
int i=0;
public int run(){
while(true){
i++;
System.out.println("i="+i);
} //End while
return 1;
}//End run
}//End class
1) It will compile and the run method will print out the increasing value of i.
2) It will compile and calling start will print out the increasing value of i.
3) The code will cause an error at compile time.
4) Compilation will cause an error because while cannot take a parameter of true.
Answer to Question 33
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Question 34)
Which of the following statements about this code are true?
public class Morecombe{
public static void main(String argv[]){
Morecombe m = new Morecombe();
m.go(new Turing(){});
}
public void go(Turing t){
t.start();
}
}
class Turing extends Thread{
public void run(){
for(int i =0; i < 2; i++){
System.out.println(i);
}
}
}
1) Compilation error due to malformed parameter to go method
2) Compilation error, class Turing has no start method
3) Compilation and output of 0 followed by 1
4) Compilation but runtime error
Answer to Question 34
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Question 35)
What will be the result when you attempt to compile and run the following code?.
public class Conv{
public static void main(String argv[]){
Conv c=new Conv();
String s=new String("ello");
c.amethod(s);
}
public void amethod(String s){
char c=´H´;
c+=s;
System.out.println(c);
}
}
1) Compilation and output the string "Hello"
2) Compilation and output the string "ello"
3) Compilation and output the string elloH
4) Compile time error
Answer to Question 35
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Question 36)
Given the following code, what test would you need to put in place of the comment line?
//place test here
to result in an output of the string
Equal
public class EqTest{
public static void main(String argv[]){
EqTest e=new EqTest();
}
EqTest(){
String s=" Java ";
String s2="java";
//place test here {
System.out.println("Equal");
}else
{
System.out.println("Not equal");
}
}
}
1) if(s==s2)
2) if(s.equals(s2)
3) if(s.equalsIgnoreCase(s2))
4)if(s.noCaseMatch(s2))
Answer to Question 36
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Question 37)
Given the following code
import java.awt.*;
public class SetF extends Frame{
public static void main(String argv[]){
SetF s=new SetF();
s.setSize(300,200);
s.setVisible(true);
}
}
How could you set the frame surface color to pink
1)s.setBackground(Color.pink);
2)s.setColor(PINK);
3)s.Background(pink);
4)s.color=Color.pink
Answer to Question 37
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Question 38)
How can you change the current working directory using an instance of the File class called FileName?
1) FileName.chdir("DirName")
2) FileName.cd("DirName")
3) FileName.cwd("DirName")
4) The File class does not support directly changing the current directory.
Answer to Question 38
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Question 39)
If you create a TextField with a constructor to set it to occupy 5 columns, what difference will it make if you use it with a proportional font (ie Times Roman) or a fixed pitch typewriter style font (Courier).
1)With a fixed font you will see 5 characters, with a proportional it will depend on the width of the characters
2)With a fixed font you will see 5 characters,with a proportional it will cause the field to expand to fit the text
3)The columns setting does not affect the number of characters displayed
4)Both will show exactly 5 characters
Answer to Question 39
Question 40)
Given the following code how could you invoke the Base constructor that will print out the string "base constructor";
class Base{
Base(int i){
System.out.println("base constructor");
}
Base(){
}
}
public class Sup extends Base{
public static void main(String argv[]){
Sup s= new Sup();
//One
}
Sup()
{
//Two
}
public void derived()
{
//Three
}
}
1) On the line After //One put Base(10);
2) On the line After //One put super(10);
3) On the line After //Two put super(10);
4) On the line After //Three put super(10);
Answer to Question 40
Question 41)
Given the following code what will be output?
public class Pass{
static int j=20;
public static void main(String argv[]){
int i=10;
Pass p = new Pass();
p.amethod(i);
System.out.println(i);
System.out.println(j);
}
public void amethod(int x){
x=x*2;
j=j*2;
}
}
1) Error: amethod parameter does not match variable
2) 20 and 40
3) 10 and 40
4) 10, and 20
Answer to Question 41
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Question 42)
What code placed after the comment //For loop would result in the population of every element of the array ia[] with a value from variable i.?
public class Lin{
public static void main(String argv[]){
Lin l = new Lin();
l.amethod();
}
public void amethod(){
int ia[] = new int[4];
//Start For loop
{
ia[i]=i;
System.out.println(ia[i]);
}
}
}
1) for(int i=0; i < ia.length() -1; i++)
2) for (int i=0; i< ia.length(); i++)
3) for(int i=1; i < 4; i++)
4) for(int i=0; i< ia.length;i++)
Answer to Question 42
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Question 43)
What will be the result when you try to compile and run the following code?
private class Base{
Base(){
int i = 100;
System.out.println(i);
}
}
public class Pri extends Base{
static int i = 200;
public static void main(String argv[]){
Pri p = new Pri();
System.out.println(i);
}
}
1) Error at compile time
2) 200
3) 100 followed by 200
4) 100
Answer to Question 43
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Question 44)
What will the following code print out?
public class Oct{
public static void main(String argv[]){
Oct o = new Oct();
o.amethod();
}
public void amethod(){
int oi= 012;
System.out.println(oi);
}
}
1)12
2)012
3)10
4)10.0
Answer to Question 44
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