Given: 1. interface A { void x(); } 2. class B implements A { public void x() {} public void y() {} } 3. class C extends B { public void x() {} } And: 4. java.util.List list = new java.util.ArrayList (); 5. list.add(new B()); 6. list.add(new C()); 7. for (A a : list) { 8. a.x(); 9. a.y(); 10. } What is the result?

Correct Answer is : Compilation fails because of an error in line 9.

An exception is thrown at runtime.

Compilation fails because of an error in line 4.

Compilation fails because of an error in line 5.

Compilation fails because of an error in line 7.

Compilation fails because of an error in line 9.

Test Index

Collections and Generics

Question : 22

Total: 53

Given:

1. interface A { void x(); }
2. class B implements A { public void x() {} public void y() {} }
3. class C extends B { public void x() {} }
And:
4. java.util.List < A > list = new java.util.ArrayList < A > ();
5. list.add(new B());
6. list.add(new C());
7. for (A a : list) {
8.   a.x();
9.   a.y();
10. }

What is the result?

The code runs with no output.
An exception is thrown at runtime.
Compilation fails because of an error in line 4.
Compilation fails because of an error in line 5.
Compilation fails because of an error in line 7.
Compilation fails because of an error in line 9.

Validate

Go to Question:

Prev Question

Next Question