1下面哪個是正確的類聲明？假設每一段文本都做爲一個名稱爲Fred.java的文件的全部內容？ a
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;
}
}
A. a)
B. b)
C. c)
D. d)
2.在類設計中，類的成員變量要求僅僅能夠被同一package下的類訪問，請問應該使用下列哪個修辭詞 d
A. protected
B. public
C. private
D. 不需要任何修辭詞
3.下面那個是Runable接口的方法？a
A. run
B. start
C. yield
D. stop
4.給出類框架如下：
class Example{
private int x;
//rest of class body…
}
假定通過java Example調用x，下列哪個語句能夠使得在Example.java的main方法中直接訪問x? b
A. 聲明x爲public而不是private
B. 聲明x爲static而不是private
C. 聲明x爲protected而不是private
D. 聲明x爲final而不是private
5.給出：以下類
public class ReturnIt{
ReturnType methodA(byte x,double y){
return (short)x/y*2;
}
}
對於在第二行的方法methodA，他的返回值的類型應該是 f
A. int
B. byte
C. long
D. short
E. float
F. double
6.下面列出的那個是java的保留字？ b
A. if
B. goto
C. while
D. case
E. then
7.十進制變量i的值爲12，那麼八進制的變量i的值爲： d
A. O08
B. O10
C. O12
D. O14
E. O16
8.下列哪些說法是正確的？ d
A. 在collection類樹上，最頂層的類叫做Collection
B. collection接口有個方法是enumerator
C. interator方法返回一個Vetor類的實例
D. set接口是爲了那些不重複的元素設計的
9.現有下列代碼片斷：
switch(x){
case 1: System.out.println("Test 1");break;
case 2:
case 3: System.out.println("Test 2");break;
default: System.out.println("end");
}
X爲何值時將輸出"Test 2" c
A. 1或2
B. 1或2或3
C. 2或3
D. 3
E. default
10.public class Test{
public int aMethod(){
static int i=0;
i++;
return i;
}
public static void main(String args[]){
Test test = new Test();
test.aMethod();
int j=test.aMethod();
System.out.println(j);
}
}
結果是什麼？ a
A. 編譯失敗
B. 編譯成功和程序打出"0"
C. 編譯成功和程序打出"1"
D. 編譯成功和程序打出"2"
11. 選擇有效的java命名 a d
A. userName
B. %passwd
C. 3d_game
D. $charge
E. this
12. 變量 "result" 是 boolean類型，下列那些表達式是合法的 a b
A. result = true;
B. if ( result ) { // do something... }
C. if ( result!= 0 ) { // so something... }
D. result = 1
13。You have the following code. Which numbers will cause "Test2" to be printed? b c d
switch(x){
case 1:
System.out.println("Test1");
case 2:
case 3:
System.out.println("Test2");
break;
}
System.out.println("Test3");
}
A. 0
B. 1
C. 2
D. 3
E. 4
14. Given the following code:
1) class Parent {
2) private String name;
3) public Parent(){}
4) }
5) public class Child extends Parent {
6) private String department;
7) public Child() {}
8) public String getValue(){ return name; }
9) public static void main(String arg[]) {
10) Parent p = new Parent();
11) }
12) }
Which line will cause error? d
A. line 3
B. line 6
C. line 7
D. line 8
E. line 10
15.class Parent {
String one, two;
public Parent(String a, String b){
one = a;
two = b;
}
public void print(){ System.out.println(one); }
}
public class Child extends Parent {
public Child(String a, String b){
super(a,b);
}
public void print(){
System.out.println(one + " to " + two);
}
public static void main(String arg[]){
Parent p = new Parent("south", "north");
Parent t = new Child("east", "west");
p.print();
t.print();
}
}
Which of the following is correct? e
A. Cause error during compilation.
B. south east
C. south to north east to west
D. south to north east
E. south east to west
16.下列代碼結果輸出多少行？ d
public class Test {
public static void main(String args[]) {
int[][][] x = new int[3][][];
int j,i;
x[0] = new int[4][];
x[1] = new int[2][];
x[2] = new int[5][];
for(i=0;i<x.length;i++){
for(j=0;j<x[i].length;j++){
x[i][j]= new int[i+j+1];
System.out.println();
System.out.println("size = "+x[i][j].length);
}
}
}
}
A， 8 B， 8 C， 10 D， 11 E， 12
17.Which two statements are true? (Choose two) b d
1. class A {
2. A() { }
3. }
4.
5. class B extends A {
6. }
A. Class B’s constructor is public.
B. Class B’s constructor has no arguments.
C. Class B’s constructor includes a call to this().
D. Class B’s constructor includes a call to super().
18. int i = 1,j = 10;
do {
if(i>j) {
break;
}
j--;
} while (++i <5);
System.out.println(“i =” +i+” and j = “+j); d
What is the result?
A. i = 6 and j = 5
B. i = 5 and j = 5
C. i = 6 and j = 4
D. i = 5 and j = 6
E. i = 6 and j = 6
19.What is the result? c
1. public class Test{
2. public static void aMethod() throws Exception {
3. try {
4. throw new Exception();
5. } finally {
6. System.out.println(“finally”);
7. }
8. }
9. public static void main(String args[]) {
10. try {
11. aMethod();
12. } catch (Exception e) {
13. System.out.println(“exception”);
14. }
15. System.out.println(“finished”);
16. }
17. }
A. finally
B. exception
finished
C. finally
exception
finished
D. Compilation fails.
20.下面那句話跟等於第二行的表達。(Choose three) a b c
1. public interface Foo {
2. int k = 4;
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;