Given: 1. interface A { public void aMethod(); } 2. interface B { public void bMethod(); } 3. interface C extends A,B { public void cMethod(); } 4. class D implements B { 5. public void bMethod(){} 6. } 7. class E extends D implements C { 8. public void aMethod(){} 9. public void bMethod(){} 10. public void cMethod(){} 11. } What is the result?

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  1. Compilation fails because of an error in line 3

  2. Compilation fails because of an error in line 7

  3. Compilation fails because of an error in line 9

  4. If you define D e = new E(), then e.bMethod() invokes the version of bMethod() defined in Line 5.

  5. If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 5.

  6. If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 9.

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Correct Option: F

AI Explanation

To answer this question, let's go through each option to understand why it is correct or incorrect:

Option A) Compilation fails because of an error in line 3 - This option is incorrect. There is no error in line 3. Line 3 defines interface C, which extends interfaces A and B.

Option B) Compilation fails because of an error in line 7 - This option is incorrect. There is no error in line 7. Line 7 defines class E, which extends class D and implements interface C.

Option C) Compilation fails because of an error in line 9 - This option is incorrect. There is no error in line 9. Line 9 defines the method bMethod() in class E, which is a valid implementation of the method from interface B.

Option D) If you define D e = new E(), then e.bMethod() invokes the version of bMethod() defined in Line 5 - This option is incorrect. The variable e is declared as type D, so it can only access the methods defined in class D. Line 5 defines the method bMethod() in class D, so e.bMethod() would invoke this version of the method.

Option E) If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 5 - This option is incorrect for the same reason as option D. The variable e is still declared as type D, so it can only access the methods defined in class D, not class E.

Option F) If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 9 - This option is correct. By casting the object of class E to type D, the variable e can now access the methods defined in class E. Line 9 defines the method bMethod() in class E, so e.bMethod() would invoke this version of the method.

The correct answer is F. If you define D e = (D)(new E()), then e.bMethod() invokes the version of bMethod() defined in Line 9.

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