選擇題
1:which is the main() method return of a application?
ng
2:
what will happen when you attempt to compile and run the following code?
int output = 10;
boolean b1 = false;
if((b1 true) && ((output += 10) 20))
{
tln("we are equal " + output);
}
else
{
tln("not equal! " + output);
}
choices:
what will happen when you attempt to compile and run the following code?
int output = 10;
boolean b1 = false;
if((b1 true) && ((output += 10) 20))
{
tln("we are equal " + output);
}
else
{
tln("not equal! " + output);
}
choices:
ilation error, attempting to perform binary comparison on logical data type
ilation and output of "we are equal 10".
ilation and output of "not equal! 20".
ilation and output of "not equal! 10".
3:
what will happen when you attempt to compile and run the following code?
class base
{
int i = 99;
public void amethod()
{
tln("hod()");
}
base()
{
amethod();
}
}
public class derived extends base
{
int i = -1;
public static void main(string argv[])
{
base b = new derived();
tln(b.i);
hod();
}
public void amethod()
{
tln("hod()");
}
}
choices:
what will happen when you attempt to compile and run the following code?
class base
{
int i = 99;
public void amethod()
{
tln("hod()");
}
base()
{
amethod();
}
}
public class derived extends base
{
int i = -1;
public static void main(string argv[])
{
base b = new derived();
tln(b.i);
hod();
}
public void amethod()
{
tln("hod()");
}
}
choices:
hod() -1 hod()
hod() 99
ile time error
hod()
4:
下述程序代碼中有語法錯誤的行是( )。
int i,ia[10],ib[10]; /＊第一行＊/
for (i=0;i<=9;i++) /＊第2行＊/
ia[i]=0; /＊第3行＊/
ib=ia; /＊第4行＊/
下述程序代碼中有語法錯誤的行是( )。
int i,ia[10],ib[10]; /＊第一行＊/
for (i=0;i<=9;i++) /＊第2行＊/
ia[i]=0; /＊第3行＊/
ib=ia; /＊第4行＊/
a.第1行
b.第2行
c.第3行
d.第4行
5:
what will be the result of executing the following code?
// filename;
package packagex;
public class superclassx
{
protected void superclassmethodx()
{
}
int superclassvarx;
}
// filename
age agey;
2.
ic class subclassy extends superclassx
4.{
rclassx objx = new subclassy();
lassy objy = new subclassy();
subclassmethody()
8.{
rclassmethodx();
i;
11.i = rclassvarx;
12.}
13.}
choices:
what will be the result of executing the following code?
// filename;
package packagex;
public class superclassx
{
protected void superclassmethodx()
{
}
int superclassvarx;
}
// filename
age agey;
2.
ic class subclassy extends superclassx
4.{
rclassx objx = new subclassy();
lassy objy = new subclassy();
subclassmethody()
8.{
rclassmethodx();
i;
11.i = rclassvarx;
12.}
13.}
choices:
ilation error at line 5
ilation error at line 9
ime exception at line 11
of these
6:which are not java keywords?
t
r
7: consider the class hierarchy shown below:
——————————————————————————————————
class fourwheeler implements drivingutilities
class car extends fourwheeler
class truck extends fourwheeler
class bus extends fourwheeler
class crane extends fourwheeler
———————————————————————————————————
consider the following code below:
ingutilities du;
wheeler fw;
k mytruck = new truck();
= (drivingutilities)mytruck;
= new crane();
= du;
which of the statements below are true?
choices:
4 will not compile because an interface cannot refer to an object.
code will compile and run.
code will not compile without an explicit cast at line 6, because going down the hierarchy without casting is not allowed.
code will compile if we put an explicit cast at line 6 but will throw an exception at runtime.
8:exhibit :
1. public class test (
2. private static int j = 0;
3.
4. private static boolean methodb(int k) (
5. j += k;
6. return true;
6. )
7.
8. public static void methoda(int i) {
9. boolean b:
10. b = i < 10 | methodb (4);
11. b = i < 10 || methodb (8);
12. )
13.
14. public static void main (string args[] } (
15. methoda (0);
16. tin(j);
17. )
18. )
what is the result?
program prints “0”
program prints “4”
program prints “8”
program prints “12”
9:
public class outerclass {
private double d1 = 1.0;
//insert code here
}
you need to insert an inner class declaration at line 3. which two inner class declarations are
valid?
public class outerclass {
private double d1 = 1.0;
//insert code here
}
you need to insert an inner class declaration at line 3. which two inner class declarations are
valid?
s innerone{ public static double methoda() {return d1;} }
ic class innerone{ static double methoda() {return d1;} }
ate class innerone{ double methoda() {return d1;} }
ic class innerone{ protected double methoda() {return d1;} }
10:
the following code is entire contents of a file called ,causes precisely one error during compilation:
class subclass extends baseclass{
}
class baseclass(){
string str;
public baseclass(){
tln(“ok”);}
public baseclass(string s){
str=s;}}
public class example{
public void method(){
subclass s=new subclass(“hello”);
baseclass b=new baseclass(“world”);
}
}
which line would be cause the error?
the following code is entire contents of a file called ,causes precisely one error during compilation:
class subclass extends baseclass{
}
class baseclass(){
string str;
public baseclass(){
tln(“ok”);}
public baseclass(string s){
str=s;}}
public class example{
public void method(){
subclass s=new subclass(“hello”);
baseclass b=new baseclass(“world”);
}
}
which line would be cause the error?
a.9
b.10
c.11
d.12
11:
string s=”example string”;which operation is not legal?
string s=”example string”;which operation is not legal?
i=th();
b.s[3]=”x”;
ng short_s=();
ng t=”root”+s;
12:軟件生命週期的瀑布模型把軟件項目分為3個階段、8個子階段，以下哪一個是正常的開發順序?
a.計劃階段、開發階段、運行階段
b.設計階段、開發階段、編碼階段
c.設計階段、編碼階段、維護階段
d.計劃階段、編碼階段、測試階段
13:which statements about java code security are not true?
bytecode verifier loads all classes needed for the execution of a program.
uting code is performed by the runtime interpreter.
runtime the bytecodes are loaded, checked and run in an interpreter.
class loader adds security by separating the namespaces for the classes of the local file system from those imported from network sources.
14:a class design requires that a member variable should be accessible only by same package, which modifer word should be used?
ected
ic
modifer
ate
15:
give the following method:
public void method( ){
string a,b;
a=new string(“hello world”);
b=new string(“game over”);
tln(a+b+”ok”);
a=null;
a=b;
tln(a);
}
in the absence of compiler optimization, which is the earliest point the object a refered is definitely elibile to be garbage collection.
give the following method:
public void method( ){
string a,b;
a=new string(“hello world”);
b=new string(“game over”);
tln(a+b+”ok”);
a=null;
a=b;
tln(a);
}
in the absence of compiler optimization, which is the earliest point the object a refered is definitely elibile to be garbage collection.
re line 5
re line 6
re line 7
re line 9
簡答題
16:請闡述一下你對java多線程中“鎖”的概念的理解。
17:列出jsp中包含外部文件的方式，兩者有何區別。
18:請談談對一個系統設計的總體思路。針對這個思路，你覺得應該具備哪些方面的知識?
19:struts2中的攔截器，你用過那些自帶的攔截器，自己寫過的.嗎?
20:怎樣在複雜的各種形式的網頁中提取mp3下載的結構化數據?
21:編寫一個在二叉排序樹中查找大小為第k的元素的算法。
22:java多線程編程。 用java寫一個多線程程序，如寫四個線程，二個加1，二個對一個變量減一，輸出。
23:不允許使用系統時間，寫出一個隨機數生成函數。
24:hibernate中的id(主鍵)生成器有那些?或者你常用的是那些?
25:error和exception有什麼區別?