Click the Exhibit button. 1. public class A { 2. public void method1() { 3. B b=new B(); 4. b.method2(); 5. // more code here 6. } 7. } 1. public class B { 2. public void method2() { 3.C c=new C(); 4. c.method3(); 5. // more code here 6. } 7. } 1. public class C { 2. public void method3() { 3. // more code here 4. } 5. } Given: 25. try { 26. A a=new A(); 27. a.method1(); 28. } catch (Exception e) { 29. System.out.print(”an error occurred”); 30. } Which two are true if a NullPointerException is thrown on line 3 of class C? (Choose two.)

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  1. The application will crash.

  2. The code on line 29 will be executed.

  3. The code on line 5 of class A will execute.

  4. The code on line 5 of class B will execute.

  5. The exception will be propagated back to line 27.

Show answer
Correct Option: B,E

AI Explanation

To answer this question, let's analyze the code and go through each option to determine which ones are true if a NullPointerException is thrown on line 3 of class C.

Given code:

1. public class A {
2.     public void method1() {
3.         B b = new B();
4.         b.method2();
5.         // more code here
6.     }
7. }

1. public class B {
2.     public void method2() {
3.         C c = new C();
4.         c.method3();
5.         // more code here
6.     }
7. }

1. public class C {
2.     public void method3() {
3.         // more code here
4.     }
5. }

25. try {
26.     A a = new A();
27.     a.method1();
28. } catch (Exception e) {
29.     System.out.print("an error occurred");
30. }

Options:

A. The application will crash. B. The code on line 29 will be executed. C. The code on line 5 of class A will execute. D. The code on line 5 of class B will execute. E. The exception will be propagated back to line 27.

Let's analyze each option:

Option A) The application will crash - This option is incorrect because the application will not crash. When a NullPointerException is thrown, it can be caught by an exception handler to prevent the application from crashing.

Option B) The code on line 29 will be executed - This option is correct. Since a NullPointerException is thrown on line 3 of class C, the catch block starting on line 28 will catch the exception, and the code on line 29 (System.out.print("an error occurred");) will be executed.

Option C) The code on line 5 of class A will execute - This option is incorrect. If a NullPointerException is thrown on line 3 of class C, the execution of method1 in class A will not reach line 5 because the exception will be caught in the catch block on line 28.

Option D) The code on line 5 of class B will execute - This option is incorrect. If a NullPointerException is thrown on line 3 of class C, the execution of method2 in class B will not reach line 5 because the exception will be caught in the catch block on line 28.

Option E) The exception will be propagated back to line 27 - This option is correct. If a NullPointerException is thrown on line 3 of class C, the catch block on line 28 will catch the exception, and the control flow will propagate back to line 27 (a.method1();).

Therefore, the correct options are B and E.

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