i2 == startingI returns true.
i2 == startingI returns false.
i2.equals(startingI) returns true.
i2.equals(startingI) returns false.
第1题:
1. package foo; 2. 3. import java.util.Vector; 4. 5. private class MyVector extends Vector { 6. int i = 1; 7. public MyVector() { 8. i = 2; 9. } 10. } 11. 12. public class MyNewVector extends MyVector { 13. public MyNewVector () { 14. i = 4; 15. } 16. public static void main (String args []) { 17. MyVector v = new MyNewVector(); 18. } 19. } The file MyNewVector.java is shown in the exhibit. What is the result?()
第2题:
11. class Converter { 12. public static void main(String[] args) { 13. Integer i = args[0]; 14. int j = 12; 15. System.out.println(”It is “ + (j==i) + “that j==i.”); 16. } 17. } What is the result when the programmer attempts to compile the code and run it with the command java Converter 12?()
第3题:
11. public class Test { 12. public void foo() { 13. assert false; 14. assert false; 15. } 16. public void bar(){ 17. while(true){ 18. assert false; 19. } 20. assert false; 21. } 22. } What causes compilation to fail?()
第4题:
public class test ( private static int j = 0; private static boolean methodB(int k) ( j += k; return true; ) public static void methodA(int i)( boolean b: b = i < 10 | methodB (4); b = i < 10 || methodB (8); ) public static void main (String args[])( methodA (0); system.out.printIn(j); ) ) What is the result?()
第5题:
11. class Person { 12. String name = “No name‟; 13. public Person(String nm) { name = nm; } 14. } 15. 16. class Employee extends Person { 17. String emplD = “0000”; 18. public Employee(String id) { empID = id; } 19. } 20. 21. public class EmployeeTest { 22. public static void main(String[] args) { 23. Employee e = new Employee(”4321”); 24. System.out.println(e.empID); 25. } 26. } What is the result?()
第6题:
10. class Inner { 11. private int x; 12. public void setX( int x) { this.x = x; } 13. public int getX() { return x; } 14. } 15. 16. class Outer { 17. private Inner y; 18. public void setY( Inner y) { this.y = y; } 19. public Inner getY() { return y; } 20. } 21. 22. public class Gamma { 23. public static void main( String[] args) { 24. Outer o = new Outer(); 25. Inner i = new Inner(); 26.int n=10; 27. i.setX(n); 28. o.setY(i); 29. // insert code here 30. System.out.println( o.getY().getX()); 31. } 32. } Which three code fragments, added individually at line 29, produce the output 100?()
第7题:
10. public class MyClass { 11. 12. public Integer startingI; 13. public void methodA() { 14. Integer i = new Integer(25); 15. startingI = i; 16. methodB(i); 17. } 18. private void methodB(Integer i2) { 19. i2 = i2.intValue(); 20. 21. } 22. } If methodA is invoked, which two are true at line 20?()
第8题:
n = 100;
i.setX( 100);
o.getY().setX( 100);
i = new Inner(); i.setX( 100);
o.setY( i); i = new Inner(); i.setX( 100);
i = new Inner(); i.setX( 100); o.setY( i);
第9题:
StackOverflowError
NullPointerException
NumberFormatException
IllegalArgumentException
ExceptionlnlnitializerError
第10题:
p.setWeight(420);
p.changePayload(420);
p = new Payload(420);
Payload.setWeight(420);
p = Payload.setWeight(420);
p = new Payload(); p.setWeight(420);
第11题:
Line 13
Line 14
Line 18
Line 20
第12题:
11. public void genNumbers() { 12. ArrayList numbers = new ArrayList(); 13. for (int i=0; i<10; i++) { 14. int value = i * ((int) Math.random()); 15. Integer intObj = new Integer(value); 16. numbers.add(intObj); 17. } 18. System.out.println(numbers); 19. } Which line of code marks the earliest point that an object referenced by intObj becomes a candidate for garbage collection?()
第13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14题:
11. class Payload { 12. private int weight; 13. public Payload(int wt) { weight = wt; } 13. public void setWeight(mt w) { weight = w; } 15. public String toString { return Integer.toString(weight); } 16. } 17. 18. public class TestPayload { 19. static void changePayload(Payload p) { 20. /* insert code here */ 21. } 22. 23. public static void main(String[] args) { 24. Payload p = new Payload(); 25. p.setWeight(1024); 26. changePayload(p); 27. System.out.println(”The value of p is “+ p); 28. } 29. } Which statement, placed at line 20, causes the code to print “The value of p is 420.”?()
第15题:
11.classA { 12. public void process() { System.out.print(”A “); } } 13. class B extends A { 14. public void process() throws RuntimeException { 15. super.process(); 16. if (true) throw new RuntimeException(); 17. System.out.print(“B”); }} 18. public static void main(String[] args) { 19. try { ((A)new B()).process(); } 20. catch (Exception e) { System.out.print(”Exception “); } 21. } What is the result?()
第16题:
1. class A implements runable ( 2. int i; 3. public void run () ( 4. try ( 5. thread.sleep(5000); 6. i= 10; 7. ) catch(InterruptedException e) {} 8. ) 9. ) 10. 11. public class Test { 12. public static void main (string args) ( 13. try ( 14. A a = new A (); 15. Thread t = new Thread (a); 16. t.start(); 17. 18. int j= a.i; 19. 20. ) catch (Exception e) {} 21. ) 22. ) Which statement al line 17 will ensure that j=10 at line 19?()
第17题:
public class test { public static void add3 (Integer i){ int val = i.intValue ( ); val += 3; i = new Integer (val); } public static void main (String args [ ] ) { Integer i = new Integer (0); add3 (i); system.out.printIn (i.intValue ( ) ); } } What is the result?()
第18题:
1. package foo; 2. 3. import java.util.Vector; 4. 5. protected class MyVector Vector { 6. init i = 1; 7. public MyVector() { 8. i = 2; 9. } 10. } 11. 12. public class MyNewVector extends MyVector { 13. public MyNewVector() { 14. i = 4; 15. } 16. public static void main(String args[]) { 17. MyVector v = new MyNewVector(); 18. } 19. } What is the result?()
第19题:
three
other
An exception is thrown at runtime.
Compilation fails because of an error on line 12.
Compilation fails because of an error on line 13.
Compilation fails because of an error on line 15.
第20题:
Compilation will fail.
The program prints “0”.
The program prints “3”.
Compilation will succeed but an exception will be thrown at line 3.
第21题:
The program prints “0”
The program prints “4”
The program prints “8”
The program prints “12”
The code does not complete.
第22题:
i2 == startingI returns true.
i2 == startingI returns false.
i2.equals(startingI) returns true.
i2.equals(startingI) returns false.