10. class Line { 11. public static class Point { } 12. } 13. 14. class Triangle { 15. // insert code here 16. } Which code, inserted at line 15, creates an instance of the Point class defined in Line?()
第1题:
1. public class Outer{ 2. public void someOuterMethod() { 3. // Line 3 4. } 5. public class Inner{} 6. public static void main( String[]argv ) { 7. Outer o = new Outer(); 8. // Line 8 9. } 10. } Which instantiates an instance of Inner?()
第2题:
1. public class a { 2. public void method1() { 3. try { 4. B b=new b(); 5. b.method2(); 6. // more code here 7. } catch (TestException te) { 8. throw new RuntimeException(te); 9. } 10. } 11. } 1. public class b { 2. public void method2() throws TestException { 3. // more code here 4. } 5. } 1. public class TestException extends Exception { 2. } Given: 31. public void method() { 32. A a=new a(); 33. a.method1(); 34. } Which is true if a TestException is thrown on line 3 of class b?()
第3题:
1. public class X { 2. public object m () { 3. object o = new float (3.14F); 4. object [] oa = new object [1]; 5. oa[0]= o; 6. o = null; 7. oa[0] = null; 10. return o; 9. } 10. } When is the float object created in line 3, eligible for garbage collection?()
第4题:
1. public class A { 2. 3. private int counter = 0; 4. 5. public static int getInstanceCount() { 6. return counter; 7. } 8. 9. public A() { 10. counter++; 11. } 12. 13. } Given this code from Class B: 25.A a1 =new A(); 26. A a2 =new A(); 27. A a3 =new A(); 28. System.out.printIn(A.getInstanceCount() ); What is the result?()
第5题:
10. class Line { 11. public class Point { public int x,y; } 12. public Point getPoint() { return new Point(); } 13. } 14. class Triangle { 15. public Triangle() { 16. // insert code here 17. } 18. } Which code, inserted at line 16, correctly retrieves a local instance of a Point object?()
第6题:
Compilation succeeds and 4 is printed.
Compilation succeeds and 43 is printed.
An error on line 9 causes compilation to fail.
An error on line 14 causes compilation to fail.
Compilation succeeds but an exception is thrown at line 9.
第7题:
public void foo() { /* more code here */ }
private void foo() { /* more code here */ }
protected void foo() { /* more code here */ }
int foo() { /* more code here */ }
void foo() { /* more code here */ }
第8题:
new Inner(); // At line 3
new Inner(); // At line 8
new o.Inner(); // At line 8
new Outer.Inner(); // At line 8
第9题:
Point p = Line.getPoint();
Line.Point p = Line.getPoint();
Point p = (new Line()).getPoint();
Line.Point p = (new Line()).getPoint();
第10题:
Compilation will succeed if a extends b.
Compilation will succeed if b extends a.
Compilation will always fail because of an error in line 7.
Compilation will always fail because of an error in line 8.
第11题:
Line 33 must be called within a try block.
The exception thrown by method1 in class a is not required to be caught.
The method declared on line 31 must be declared to throw a RuntimeException.
On line 5 of class a, the call to method2 of class b does not need to be placed in a try/catch block.
第12题:
After line 8.
After line 10.
After line 4, when doBar() completes.
After line 11, when main() completes.
第13题:
Class TestException 1. public class TestException extends Exception { 2. } Class a: 1. public class a { 2. 3. public String sayHello(String name) throws TestException { 4. 5. if(name == null) { 6. throw new TestException(); 7. } 8. 9. return “Hello “+ name; 10. } 11. 12. } A programmer wants to use this code in an application: 45. A a=new A(); 46. System.out.println(a.sayHello(”John”)); Which two are true?()
第14题:
1. public class A { 2. public void doit() { 3. } 4. public String doit() { 5. return “a”; 6. } 7. public double doit(int x) { 8. return 1.0; 9. } 10.} What is the result?()
第15题:
1.public class Test { 2.public static void main (String args[]) { 3.class Foo { 4.public int i = 3; 5.} 6.Object o = (Object) new Foo(); 7.Foo foo = (Foo)o; 8.System.out.printIn(foo. i); 9. } 10.} What is the result?()
第16题:
1. class Bar { } 1. class Test { 2. Bar doBar() { 3. Bar b = new Bar(); 4. return b; 5. } 6. public static void main (String args[]) { 7. Test t = new Test(); 8. Bar newBar = t.doBar(); 9. System.out.println(“newBar”); 10. newBar = new Bar(); 11. System.out.println(“finishing”); 12. } 13. } At what point is the Bar object, created on line 3, eligible for garbage collection?()
第17题:
Just after line 5.
Just after line 6.
Just after line 7.
Just after line 8(that is, as the method returns).
第18题:
The application will crash.
The code on line 29 will be executed.
The code on line 5 of class A will execute.
The exception will be propagated back to line 27.
The code on line 5 of class B will execute.
第19题:
Compilation of class A fails.
Line 28 prints the value 3 to System.out.
Line 28 prints the value 1 to System.out.
A runtime error occurs when line 25 executes.
Compilation fails because of an error on line 28.
第20题:
Point p = new Point();
Line.Point p = new Line.Point();
The Point class cannot be instatiated at line 15.
Line 1 = new Line() ; 1.Point p = new 1.Point();
第21题:
Point p = new Point();
Line.Point p = new Line.Point();
The Point class cannot be instatiated at line 15.
Line l = new Line() ; l.Point p = new l.Point();
第22题:
Line 5
Line 6
Line 7
Line 8
Line 9
Line 10
第23题:
Direction d = NORTH;
Nav.Direction d = NORTH;
Direction d = Direction.NORTH;
Nav.Direction d = Nav.Direction.NORTH;