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4
第1题:
1. public class SwitchTest { 2. public static void main (String []args) { 3. System.out.PrintIn(“value =” +switchIt(4)); 4. } 5. public static int switchIt(int x) { 6. int j = 1; 7. switch (x) { 8. case 1: j++; 9. case 2: j++; 10. case 3: j++; 11. case 4: j++; 12. case 5: j++; 13. default:j++; 14. } 15. return j + x; 16. } 17. } What is the output from line 3?()
第2题:
1. import java.util.*; 2. class ForInTest { 3. static List list = new ArrayList(); 4. 5. static List getList() { return list; } 6. 7. public static void main(String [] args) { 8. list.add("a"); list.add("b"); list.add("c"); 9. // insert code here 10. System.out.print(o); 11. } 12. } 第 9 行插入哪一项将输出 abc?()
第3题:
现有: 1. class Synapse { 2. protected int gap() { return 7; } 3. } 4. 5. class Creb extends Synapse { 6. // insert code here 7. } 分别插入到第 6 行,哪三行可以编译?()
第4题:
1. public class Boxer1 { 2. Integer i; 3. int x; 4. public Boxer1(int y) { 5. x=i+y; 6. System.out.println(x); 7. } 8. public static void main(String[] args) { 9. new Boxer1(new Integer(4)); 10. } 11. } What is the result?()
第5题:
1. class SuperFoo { 2. SuperFoo doStuff(int x) { 3. return new SuperFoo(); 4. } 5. } 6. 7. class Foo extends SuperFoo { 8. //insert code here 9. } 下面哪三项分别插入到第8行,可以编译?()
第6题:
class Passer { static final int x = 5; public static void main(String [] args) { new Passer().go(x); System.out.print(x); } void go(int x) { System.out.print(++x); } } 结果是什么?()
第7题:
The program runs and prints “0”
The program runs and prints “1”
The program runs but aborts with an exception.
An error “possible undefined variable” at line 4 causes compilation to fail.
An error “possible undefined variable” at line 9 causes compilation to fail.
第8题:
0
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5
The code will not compile.
第9题:
0
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2
3
第10题:
for(char o: list)
for(Object o: getList())
for(Object o: getList();)
for(Object o: o.getList())
第11题:
The value “4” is printed at the command line.
Compilation fails because of an error in line 5.
Compilation fails because of an error in line 9.
A NullPointerException occurs at runtime.
A NumberFormatException occurs at runtime.
An IllegalStateException occurs at runtime.
第12题:
Compilation succeeds and 1 is printed.
Compilation succeeds and 2 is printed.
An error at line 8 causes compilation to fail.
An error at line 13 causes compilation to fail.
An error at line 14 causes compilation to fail.
第13题:
现有: 1. class HorseRadish { 2. // insert code here 3. protected HorseRadish(int x) { 4. System.out.println("bok choy"); 5. } 6. } 7. class Wasabi extends HorseRadish { 8. public static void main(String [] args) { 9. Wasabi w = new Wasabi(); 10. } 11. } 分别插入到第 2 行,哪两项允许代码编译并产生"bok choy" 输出结果?()
第14题:
1. public class Test { 2. public static String output =””; 3. 4. public static void foo(int i) { 5. try { 6. if(i==1) { 7. throw new Exception(); 8. } 9. output += “1”; 10. } 11. catch(Exception e) { 12. output += “2”; 13. return; 14. } 15. finally { 16. output += “3”;17. } 18. output += “4”; 19. } 20. 21. public static void main(String args[]) { 22. foo(0); 23. foo(1); 24. 25. }26. } What is the value of the variable output at line 23?()
第15题:
1. class Calc { 2. public static void main(String [] args) { 3. try { 4. int x = Integer.parseInt("42a"); 5. //insert code here 6. System.out.print("oops "); 7. } 8. } 9. } 下面哪两行分别插入到第五行,会导致输出“oops”?()
第16题:
1. class Passer2 { 2. //insert code here 3. static int bigState = 42; 4. public static void main(String [] args) { 5. bigState = p2.go(bigState); 6. System.out.print(bigState); 7. } 8. int go(int x) { 9. return ++x; 10. } 11. } 和4段代码片段: static Passer2 p2 = new Passer2(); final static Passer2 p2 = new Passer2(); private static Passer2 p2 = new Passer2(); final private static Passer2 p2 = new Passer2(); 有多少行分别插入到第2行,可以编译?()
第17题:
1. class MyThread implements Runnable { 2. public void run() { 3. System.out.print("go "); 4. } 5. 6. public static void main(String [] args) { 7. // insert code here 8. t.start(); 9. } 10. } 和如下四句: Thread t = new MyThread(); MyThread t = new MyThread(); Thread t = new Thread(new Thread()); Thread t = new Thread(new MyThread()); 分别插入到第5行,有几个可以通过编译?()
第18题:
1. public class test ( 2. public static void main(string args[]) { 3. int 1= 0; 4. while (i) { 5. if (i==4) { 6. break; 7. } 8. ++i; 9. } 10. 11. } 12. ) What is the value of i at line 10?()
第19题:
int doStuff() { return 42; }
int doStuff(int x) { return 42; }
Foo doStuff(int x) { return new Foo(); }
SuperFoo doStuff(int x) { return new Foo(); }
第20题:
} catch (ClassCastException c) {
} catch (IllegalStateException c) {
} catch (NumberFormatException n) {
} catch (IllegalArgumentException e) {
第21题:
Value is: 8
Compilation fails.
Value is: 12
Value is: -12
The code runs with no output.
An exception is thrown at runtime.
第22题:
Value = 3
Value = 4
Value = 5
Value = 6
Value = 7
Value = 8
第23题:
55
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65
66