杭州天丽科技有限公司 JAVA高级程序员笔试题

http://www.mianwww.com/html/2013/04/18345.html

选择题

1:
1. What will be the result of executing the following code?
2. boolean a = true;
3. boolean b = false;
4. boolean c = true;
5. if (a == true)
6. if (b == true)
7. if (c == true)    System.out.println("Some things are true in this world");
8. else       System.out.println("Nothing is true in this world!");
9.  else if (a && (b = c))  System.out.println("It's too confusing to tell what is true and what is false");
10.  else   System.out.println("Hey this won't compile");

12. Choices:
 A.The code won't compile
 B."Some things are true in this world" will be printed
 C."Hey this won't compile" will be printed
 D.None of these
2: Which of the following statements are true?
 A.The automatic garbage collection of the JVM prevents programs from ever running out of memory
 B.A program can suggest that garbage collection be performed and force it
 C.Garbage collection is platform independent
 D.An object becomes eligible for garbage collection when all references denoting it are set to null.
3:
1. What will happen when you attempt to compile and run the following code?
2.
3. class Base
4.
5. {
6.
7. int i = 99;
8.
9. public void amethod()
10.
11. {
12.
13.       System.out.println("Base.amethod()");
14.
15.     }
16.
17.     Base()
18.
19. {
20.
21.     amethod();
22.
23.     }
24.
25. }
26.
27. public class Derived extends Base
28.
29. {
30.
31. int i = -1;
32.
33.
34.
35. public static void main(String argv[])
36.
37. {
38.
39.     Base b = new Derived();
40.
41.       System.out.println(b.i);
42.
43.       b.amethod();
44.
45.     }
46.
47.     public void amethod()
48.
49. {
50.
51.       System.out.println("Derived.amethod()");
52.
53.     }
54.
55. }
56.
57. Choices:
 A.Derived.amethod() -1 Derived.amethod()
 B.Derived.amethod() 99
 C.Compile time error
 D.Derived.amethod()
4: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
5:假定a和b为int型变量,则执行下述语句组后,b的值为
a=1;
b=10;
do
{
b-=a;
a++;
} while (b--<0);
 A.9
 B.-2
 C.-1
 D.8
6:
1. What results from attempting to compile and run the following code?
2.
3. public class Ternary
4.
5. {
6.
7. public static void main(String args[])
8.
9. {
10.
11. int a = 5;
12.
13. System.out.println("Value is - " + ((a < 5) ? 9.9 : 9));
14.
15. }
16.
17. }
18.
19. Choices:
 A.prints: Value is - 9
 B.Compilation error
 C. prints: Value is - 5
 D.None of these
7:
1. String s=”Example String”;Which operation is not legal?
 A.int i=s.length();
 B.s[3]=”x”;
 C.String short_s=s.trim();
 D.String t=”root”+s;
8: 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: 


1.DrivingUtilities du; 


2.FourWheeler fw; 


3.Truck myTruck = new Truck(); 


4.du = (DrivingUtilities)myTruck; 


5.fw = new Crane(); 


6.fw = du; 


Which of the statements below are true? 


Choices:
 A.Line 4 will not compile because an interface cannot refer to an object.
 B.The code will compile and run.
 C.The code will not compile without an explicit cast at line 6, because going down the hierarchy without casting is not allowed.
 D.The code will compile if we put an explicit cast at line 6 but will throw an exception at runtime.
9:
1. Give the following java class:
2. public class Example{
3. static int x[]=new int[15];
4. public static void main(String args[]){
5. System.out.println(x[5]);
6. }
7. }
8. Which statement is corrected?
 A.When compile, some error will occur.
 B.When run, some error will occur.
 C.Output is zero.
 D.Output is null.
10:
1. Give the code fragment:
2. if(x>4){
3. System.out.println(“Test 1”);}
4. else if (x>9){
5. System.out.println(“Test 2”);}
6. else {
7. System.out.println(“Test 3”);}
8. Which range of value x would produce of output “Test 2”?
 A.x<4
 B.x>4
 C.x>9
 D.None
11:Use the operator “>>” 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
 C.1010 0000 0000 0000 0000 0000 0000 0000 >>> 4 give 0000 0000 0000 0000 0000 0000 0000 0000
 D.1010 0000 0000 0000 0000 0000 0000 0000 >>> 4 give 1111 1010 0000 0000 0000 0000 0000 0000
12:使用 JDBC 可以做到的是
 A.把二进制代码传送到任何关系数据库中
 B.把 Java 源代码传送到任何关系数据库中
 C.把表单信息传送到任何关系数据库中
 D.很容易地把 SQL 语句传送到任何关系数据库中
13:Math.round(-11.5)等於多少?
 A.-11
 B.-12
 C.-11.5
 D.none
14:软件生命周期的瀑布模型把软件项目分为3个阶段、8个子阶段，以下哪一个是正常的开发顺序?
 A.计划阶段、开发阶段、运行阶段
 B.设计阶段、开发阶段、编码阶段
 C.设计阶段、编码阶段、维护阶段
 D.计划阶段、编码阶段、测试阶段
简答题
15:找到一个子字符串，优化速度，优化空间。
16:什么是接口？为什么要定义接口？接口与抽象类有何异同？
17:下面的代码在绝大部分时间内都运行得很正常，请问在什么情况下会出现问题？问题的根源在哪里？
import java.util.LinkedList; 


public class Stack { 


LinkedList list = new LinkedList(); 


public synchronized void push(Object x) {
synchronized(list) {
list.addLast( x );
notify();
}
} 


public synchronized Object pop()
throws Exception {
synchronized(list) {
if( list.size() <= 0 ) {
wait();
}
return list.removeLast();
}
}
}
18:Java的接口和C++的虚类的相同和不同处。
19:hibernate中load()/get()区别。
20:How do you use JMX to monitor the cluster? if you have used。
21:Java中异常处理有什么优点？
22:tomcat中用来编译JSP页面的是哪个类，或者哪个模块？
23:Class.forName的作用?为什么要用?
24:jsp有哪些动作?作用分别是什么?
25:写一个程序，把一个100以内的自然数分解因数。（自然数分解因数就是将一个自然数分解为几个素数的乘积，提示,由于该数不是很大,所以可以将质数保存在数组中,以加快计算速度)