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整理人: zjxyz(2001-05-10 22:19:57), 站内信件
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【 在 eassy (eassy) 的大作中提到: 】
: 请问：谁有或那里有Sun的Java认证的考卷？能不能Email给我.
: [email protected],谢谢！
: 回复时请选“发信给原作者”
Java程序员认证模拟题
一.说明
1.考试形式:网络计算机
2.考题形式:多选,单选和简答
3.题量: 60
4.考试时间:120分钟
5.如果需要参考答案请与胡老师联系。（[email protected])
二.模拟题:
1.Which statement about the garbage collection mechanism are true?
A.Garbage collection require additional programe code in cases where m
ultiple threads are running.
B.The programmer can indicate that a referance through a local variabl
e is no longer of interest.
C.The programmer has a mechanism that explicity and immediately frees
the memory used by Java objects.
D.The garbage collection mechanism can free the memory used by Java Ob
ject at explection time.
E.The garbage collection system never reclaims memory from objects whi
le are still accessible to running user thread.
2.Give the following method:
1) public void method(){
2) String a,b;
3) a=new String("hello world");
4) b=new String("game over");
5) System.out.println(a+b+"ok");
6) a=null;
7) a=b;
8) System.out.println(a);
9) }
In the absence of compiler optimization,which line is the earliest poi
nt the object a refered is definitely elibile to be garbage collected?
A.3 B.5 C.6 D.7 E.9
3.In the class java.awt.AWTEvent,which is the parent class upon which
jdk1.1 awt events are based there is a method called getID(),which phr
ase most accerrately describes in significance of the reture value of
this method?
A.It is a reference to the object directly affected by the cause of th
e event.
B.It is an indication of the nature of the cause of the event.
C.It is an indication of the position of the mouse when it caused the
event.
D.In the case of a mouse click,it is an indication of the text under t
he mouse at the time of the event.
E.It tells the state of certain keys on the keybord at the time of the
event.
F.It is an indication of the time at which the event occurred.
4. Which statement about listener is true?
A.Most component allow multiple listeners to be added.
B.If mutiple listener be add to a single component,the event only affe
cted one listener.
C.Component don't allow multiple listeners to be add.
D.The listener mechanism allows you to call an addListener method as m
any times as is needed,specifying as many different listeners as your
design requires.
5.Give the following code:
public class Example{
public static void main(String args[]){
int I=0;
do{
System.out.println("Doing it for I is:"+ I );
}while(--i);
System.out.println("Finish");
}
}
Which will be output:
A.Doing it for I is 3 B.Doing it for I is 1 C.Doing it for I is 2
D.Doing it for I is 0 E.Doing if for I is -1 F.Finish
6.Give the code fragment:
1) switch(x){
2) case 1: System.out.println("Test 1"); break;
3) case 2:
4) case 3:System.out.println("Test 2"); break;
5) default: System.out.println("end");
6) }
which value of x would cause "Test 2" to the output:
A.1 B.2 C.3 D.default
7.Give incompleted method:
1)
2) { if(unsafe()) {//do something...}
3) else if(safe()){//do the other...}
4} }
The method unsafe() will throw an IOException,which completes the meth
od of declaration when added at line one?
A.public IOException methodName()
B.public void methodName()
C.public void methodName() throw IOException
D.public void methodName() throws IOException
F.public void methodName() throws Exception
8.Give the code fragment:
if(x>4){
System.out.println("Test 1");}
else if(x>9) {
System.out.println("Test 2");}
else {
System.out.println("Test 3");}
Which range of value of x would produce of output "Test 2"?
A.x<4 B.x>4 C.x>9 D.None
9.Give the following method:
public void example(){
try{
unsafe();
System.out.println("Test 1");
}catch(SafeException e){System.out.println("Test 2");
}finally{System.out.println("Test 3");}
System.out.println("Test 4");
}
Which will display if method unsafe() run normally?
A.Test 1 B.Test 2 C.Test 3 D.Test 4
10.Which method you define as the starting point of new thread in a cl
ass from which new the thread can be excution?
A.public void start() B.public void run() C.public void int()
D.public static void main(String args[]) E.public void runnable()
11.What wight cause the current thread to stop excutings?
A.thread of higher priority become ready. B.method sleep() be called.
C.method stop() be called D.method suspend() be called.
E.method wait() be called
12.Which modifier should be applied to a method for the lock of object
this to be obtained prior to excution any of the mehod body?
A.synchronized B.abstract C.final D.static E.public
13.The following code is entire contents of a file called Example.java
,causes precisely one error during compilation:
1) class SubClass extends BaseClass{
2) }
3) class BaseClass{
4) String str;
5) public BaseClass(){
6) System.out.println("ok");}
7) public BaseClass(String s){
8) str=s;
9) public class Example{
10) public void method(){
11) SubClass s=new SubClass("hello");
12) BaseClass b=new BaseClass("world");
13) }
14) }
15) }
16) }
Which line would be cause the error? A.9 B.10 C.11 D.12
14.Which statement is correctly declare a variable a which is suitable
for refering to an array of 30 string empty object?
A.String []a B.String a[] D.char a[][] E.String a[50] F.Object a[50]
15.Give the following java sourse fragement:
//point x
public class Interesting{
//do something
}
which statement is correctly Java syntax ant point x?
A.import java.awt.*; B.package mypackage C.static int PI=3.14
D.public class MyClass{//do other thing...} E.class MyClass{//do somet
hing...}
16.Give this class outline:
class Example{
private int x;
//rest of class body...
}
Assuming that x invoked by the code java Example,which statement can m
ade this.x be accessible in main() method of Example.java:
A.Change private int x to public int x B.change private int x to stati
c int x
C.Change private int x to protected int x D.change private int x to fi
nal int x
17.The piece of preliminary analsis work describes a class that will b
e used frequently in many unrelated parts of a project:
"The polygon object is a drawable,A polygon has vertex information sto
red in a vector,a color,
length and width."
Which Data type would be used?
A.Vector B.int C.String D.Color E.Date
18.A class design requires that a member variable should be accessible
only by same package,which modifer word should be used:
A.protected B.public C.no modifer D.private
19.Which declares for a native method in a java class corrected?
A.public native void method(){ } B.public native void method();
C.public native method(); D.public void method(){native;}
E.public void native method();
20.Which modifer should be applied to a declaration of a class member
variable for the value of variable to remain constant after the creati
on of the object?(short answer)
21.Which is the main() method's return of a application?
A.String B.byte C.char D.void
22.Which is corrected argument of main() method of a applicaton?
A.String args B.String ar[] C.Char args[][] D.StringBuffer arg[]
23."The Employee object is a person,An Employee has appointment store
in a vector,a hire date and a number of dependents."
short anwser:use shortest statement define a class of Employee.
24.Give the following class defination inseparate source files:
public class Example{
public Example(){//do something}
protected Example(){// do something}
protected void method(){//do something}
}
public class Hello extends Example{// member method and member variabl
e}
Which methods are corrected added to the class Hello?
A.public void Example(){} B.public void method(){} C.protected void me
thod(){} D.private void method() E.private otherMethod(){}
25. Float s=new Float(0.9F);
Float t=new Float(0.9F);
Double u=new Double(0.9);
Which expression's result is true?
A.s==t; B.s.equal(t); C.s==u D.t.equal(u)
26.Give following class:
class AClass{
private long val;
public AClass(long v){val=v;}
public static void main(String args[]){
AClass x=new AClass(10L);
AClass y=new AClass(10L);
AClass z=y;
long a=10L;
int b=10;
}
}
Which expression's result is true?
A.a= =b; B.a= =x; C.y= =z; D.x= =y;
E.a= =10.0;
27.A socket object has been created and connected to a standard intern
et sevice on a remote network server.Which construction give the most
suitable means for reading ASCII data one line at a time from the sock
et?
A.InputStream in=s.getInputStream();
B.DataInputStream in=new DataInputstream(s.getInputStream());
C.ByteArrayInputStream in=new ByteArrayInputStream(s.getInputStream())
;
D.BufferedReader in=new BufferedReader(new InputStreamReader(s.getInpu
tStream()));
E.BufferedReader in=new BufferedReader(new InputStreamReader(s.getInpu
tStream()),"8859-1");
28.String s="Example String";
Which operation is legal?
A.s>>>=3; B.int =s.length(); C.s[3]="x";
D.String short s=s.trim(); E.String t="root"+s;
29.Give: String str="goodby";
Which operation is legal?
A.char c=s[3]; B.int i=s.length(); C.s>>=2;
D.String lower s=s.toLowerCase(); E.s+="long ago";
30.What use to position a Button in a Frame,width of Button is affecte
d by the Frame size,which Layout Button will be set to?
A.FlowLayout; B.GridLayout; C.North of BorderLayout
D.South of BorderLayout D.Ease or West of BorderLayout
31.What use to position a Button in a Frame,size of Button is not affe
cted by the Frame size,which Layout Button will be set to?
A.FlowLayout; B.GridLayout; C.North of BorderLayout
D.South of BorderLayout D.Ease or West of BorderLayout
32.An AWT GUI under exposure condition,which one or more method will b
e invok when it redraw?
A.paint(); B.update(); C.repaint(); D.drawing();
33.Select valid identifier of Java:
A.userName B.%passwd C.3d_game D.$charge E.this
34.Which are Java keyword?
A.goto B.null C.FALSE D.native E.const
35.Run a corrected class:java -cs AClass a b c <enter>
Which statement is true?
A.args[0]="-cs"; B.args[1]="a b c"; C.args[0]="java";
D.args[0]="a"; E.args[1]='b';
36.Give the following java class:
public class Example{
static int x[]=new int[15];
public static void main(String args[]){
System.out.println(x[5]);
}
}
Which statement is corrected?
A.When compile,some error will occur.
B.When run,some error will occur.
C.Output is zearo.
D.Output is null.
37.Give the following java class:
public class Example{
public static void main(String args[]){
static int x[]=new int[15];
System.out.println(x[5]);
}
}
Which statement is corrected?
A.When compile,some error will occur.
B.When run,some error will occur.
C.Output is zearo.
D.Output is null.
38. Short answer:
The decimal value of i is 12,the octal i value is:
39.short answer:
The decimal value of i is 7,the hexadecimal is:
40.Which is the range of char?
A.2-7~27-1 B.0~216-1 C.0~216 D.0~28
41.Which is the range of int type?
A.2-16~2 16-1 B.2-31~ 2 31-1 C.2-32~2 32-1 D.2-64~2 64-1
42.Give the following class:
public class Example{
String str=new String("good");
char ch[]={'a','b','c'};
public static void main(String args[]){
Example ex=new Example();
ex.change(ex.str,ex.ch);
System.out.println(ex.str+" and "+ex.ch);
}
public void change(String str,char ch[]){
str="test ok";ch[0]="g";
}
}
Which is the output:
A.good and abc B.good and gbc C.test ok and abc D.test ok and gbc
43.Which code fragments would correctly identify the number of argumen
ts passed via command line to a Javaapplication, excluding the name of
the class that is being invoked?
A.int count = args.length; B.int count = args.length - l;
C.int count=0; while (args [count] !=null)
count ++;
D.int count=0; while
(!(args[count].equals(""))) count ++;
44.FilterOutputStream is the parent class for BufferedOutputStream, Da
taOutputStream and PrintStream. Which classes are a valid argument for
the constructor of a FilterOutputStream?
A.InputStream B.OutputStream C.File
D.RandomAccessFile E.StreamTokenizer
45.Given a TextArea using a proportional pitch font and constructed li
ke this:
TextArea t = new TextArea("12345", 5, 5);
Which statement is true?
A.the displayed width shows exactly five characters one ach line unles
s otherwise constrained
B.The displayed height is five lines unless otherwise
constrained.
C.The maximum number of characters in a line will be
five.
D.The user will be able to edit the character string
E.The displayed string can use multiple fonts
46.Given a TextArea using a proportional pitch font and constructed li
ke this:
List l=new List(5,true); Which statement is true?
A.the displayed item exactly five line unless otherwise constrained
B.The displayed item is five lines init.but can displayed more than fi
ve Item by
C.The maximum number of item in a list will be five.
D.The list is multiple mode
47.Given this skeleton of a class currently under construction:
public class Example {
int x, y,z;
public Example(int a,int b) {
//lots of complex computation
x=a;y=b;
}
public Example(int a, int b,int c) {
// do everything the same as single argument
// version of constructor
//including assignment x = a,y=b
z=c;
}
}
What is the most concise way to code the "do everything..."part of the
constructor taking two arguments? (short answer)
48.Which correctly create a two dimensional array of integers?
A.int a[][] = new int[10,10]
B.int a[10][10] = new int[][];
C.int a[][] = new int [10][10];
D.int []a[] = new int [10][10];
E.int []a[] = new int[10][10];
49.Which are correct class declarations? Assume in each case that the
text constitutes the entire contents of a file called Fred.java on a s
ystem with a case-significant file system.
A.public class Fred {
public int x = 0;
public Fred (int x) {
this.x = x;
}
}
B.public class fred
public int x = 0;
public fred (int x) {
this.x = x;
}
}
C.public class Fred extends MyBaseClass, MyOtherBaseClass {
public int x = 0;
public Fred (int xval) {
x = xval;
}
}
D.protected class Fred {
private int x = 0;
private Fred (int xval) {
x = xval;
}
}
E.import java.awt.*;
public class Fred extends Object {
int x;
private Fred (int xval) {
x = xval;
}
}
50.A class design requires that a particular member variable must be a
ccessible for direct access by any subclasses of this class, but other
wise not by classes which are not members of the same package. What sh
ould be done to achieve this?
A.The variable should be marked public
B.The variable should be marked private
C.The variable should be marked protected
D.The variable should have no special access modifier
E.The variable should be marked private and an accessor method provide
d
51.Which correctly create an array of five empty Strings?
A.String a [] = new String [5];
for (int i = 0; i < 5; a[i++] = "");
B.String a [] = {"", "", "", "", ""};
C.String a [5];
D.String [5] a;
E.String [] a = new String [5];
for (int i = 0; i < 5; a[i++] = null);
52.Which cannot be added to a Container?
A.an Applet B.a Component
C.a Container D.a MenuComponent E.a panel
53.Which is the return value of Event listener's method?
A.String B.AWTEvent C.void D.int
54.If we implements MouseEventListener,which is corrected argument of
it's method?(short answer)
55.Use the oprator ">>" and ">>>".Which statement is true?
A.1010 0000 0000 0000 0000 0000 0000 0000>>4 give
0000 1010 0000 0000 0000 0000 0000 0000
B.1010 0000 0000 0000 0000 0000 0000 0000>>4 give
1111 1010 0000 0000 0000 0000 0000 0000
A.1010 0000 0000 0000 0000 0000 0000 0000>>>4 give
0000 1010 0000 0000 0000 0000 0000 0000
A.1010 0000 0000 0000 0000 0000 0000 0000>>>4 give
1111 1010 0000 0000 0000 0000 0000 0000
56.Give following fragment.
outer:for(int i=0;i<3;i++)
inner:for(int j=0;j<3;j++){
if(j>1) break outer;
System.out.println(j+"and"+i);
}
Which will be output?
A.0 and 0 B.0 and 1 C.0 and 2 D.0 and 3
E.1 and 0 F.1 and 1 G.1 and 2 H.1 and 3
I.2 and 0 J.2 and 1 K.2 and 2 L.2 and 3
57.FilterInputStream is the parent class for BufferedInputStream, Data
InputStream and PrintStream. Which classes are a valid argument for th
e constructor of a FilterOutputStream?
A.InputStream B.OutputStream C.File
D.RandomAccessFile E.StreamTokenizer
58.Which is the main()method return?
A.String B.void C.char D.int
59.Look the inheritance ralation:
person
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man woman
In a sourse of java have the following line:
person p=new man();
What statement are corrected?
A.The expression is illegal.
B.Compile corrected but running wrong.
C.The expression is legal.
D.Will construct a person's object.
60..Look the inheritance ralation:
person
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man woman
In a sourse of java have the following line:
woman w=new man();
What statement are corrected?
A.The expression is illegal.
B.Compile corrected but running wrong.
C.The expression is legal.
D.Will construct a woman's object.
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