Java经典笔试题01

1. Given:
1. public class test (
2. public static void main (String args[]) {
3. int i = 0xFFFFFFF1; //0001
4. int j = ~i;//1110，取反
5.
6. }
7. )
What is the decimal value of j at line 5?
A. 0
B. 1
C. 14
D. -15
E. An error at line 3 causes compilation to fail.
F. An error at line 4 causes compilation to fail.
2. Given:
Integer i = new Integer (42);
Long 1 = new Long (42);
Double d = new Double (42.0);
Which two expressions evaluate to True? (Choose Two)
A. (i ==1)
B. (i == d)
C. (d == 1)
D. (i.equals (d))
E. (d.equals (i))
F. (i.equals (42))
3. Click the exhibit button:
1. public class test (
2. private static int j = 0;
3.
4. private static boolean methodB(int k) (
5. j += k;
6. return true;
7. )
8.
9. public static void methodA(int i) {
10. boolean b;
11. b = i < 10 | methodB (4);//非短路
12. b = i < 10 || methodB (8);//短路，后面不执行
13. )
14.
15. public static void main (String args[] } (
16. methodA (0);
17. system.out.printIn(j);
18. )
19. )
What is the result?
A. The program prints “0”
B. The program prints “4”
C. The program prints “8”
D. The program prints “12”
E. The code does not complete
4. Given:
1.Public class test (
2. Public static void main (String args[]) (
3. System.out.printIn (6 ^ 3); //0110 ^ 0011 = 0101
4. )
5.)
What is the output? 5
1.Which statement is correctly declare a variable a which is suitable for refering to an array of
50 string empty object? （长度为50的空数组引用）
A. String [] a
B. String a[]
C. char a[][]
D. String a[50]
F. Object a[50]
2.Which is corrected argument of main() method of application?
A. String args
B. String ar[]
C. Char args[][]
D. StringBuffer arg[]
3.Select valid identifier of Java:
A. userName
B. %passwd
C. 3d_game
D. $charge
E. this
4.Which are Java keyword?
A. goto
B. null
C. FALSE
D. native
E. const
5.Give the following java class:
public class Example{
public static void main(String args[]){
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 zero. //int默认是0
D. Output is null.
6. 怎样通过一个语句改变数组大小同时保持原值不变？
1) Use the setSize method of the Array class
2) Use Util.setSize(int iNewSize)
3) use the size() operator
4) None of the above
7. 你想用下面的代码查找数组最后一个元素的值，当你编译并运行它的时候，会发生什么？
public class MyAr{
public static void main(String argv[]){
int[] i = new int[5];
System.out.println(i[5]);//01234.下标没有5，运行时异常
}
}
1) Compilation and output of 0
2) Compilation and output of null
3) Compilation and runtime Exception
4) Compile time error
8. 作为一个好的Java 程序员，你已忘记了曾经在C/C++中知道的关于数组大小信息的知识。

如果你想遍历一个数组并停止在最后一个元素处。

你会使用下面的哪一个？
1)myarray.length();
2)myarray.length;
3)myarray.size
4)myarray.size();。