Java OCA OCP Practice Question 1793

Question

Which statement about the following program is correct? 

package mypkg;/* w  w w.  j a  v a  2  s.c  om*/
public class Main {
  class Exception1 extends RuntimeException {}
  class Exception2 extends RuntimeException {}
  class Exception1 extends RuntimeException {}
  public int m() {
     try {} catch (Exception1 d) {
        d = new RuntimeException();
        throw d;
     } catch (Exception2 | Exception1 e) {
        e = new RuntimeException();
        throw e;
     }
     return 3;
  }
  public static void main(String... wand) throws RuntimeException{
     new Main().m();
  }
}
  • A. The class compiles and does not print anything at runtime.
  • B. The code does not compile solely due to the first catch block in m().
  • C. The code does not compile solely due to the second catch block in m().
  • D. The code does not compile due to errors in both catch blocks in m().


D.

Note

The catch variable d is of type Exception1 that cannot be assigned an instance of the superclass RuntimeException without an explicit cast.

The first catch block does not compile in m().

The second catch block also does not compile, albeit for a slightly different reason.

A catch variable in a multi-catch block must be effectively final because the precise type is not known until runtime.

The compiler does not allow the variable e to be reassigned.

Option D is the correct answer.

The first catch block does allow the catch variable d to be reassigned, it just must be to a class that inherits Exception1 or is an instance of Exception1.




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