Exception Handling Objective Question and Answers

The below blog has objective questions on Exception Handling. It concentrates on usage of keywords like throws, throw, try/catch and Exception

This blog is a extension to previous blog of Core Java Objective Question Test 1


1.

1. public class Test {
2.  public static void main(String[] args) {
3.   System.out.println("hi");
4.   try {
5.    System.out.println("Here");
6.    int j=1/0;
7.    throw new UserNotFoundException();
8.    
9.   } catch (UserNotFoundException e) {
10.    System.out.println("Caught");
11.    e.printStackTrace();
12.   } finally{
13.    System.out.println("in finally");
14.   }
15.   System.out.println("After catch");
16.  }
17.  }

1. hi
Here
Exception in thread "main" java.lang.ArithmeticException: / by zero
 at ExceptionTurorial.Test.main(Test.java:12)
in finally

2. hi
Here
Exception in thread "main" java.lang.ArithmeticException: / by zero
 at ExceptionTurorial.Test.main(Test.java:12)
in finally
After catch

3. hi
here
caught
in finally
After catch

Answer : 1.
The catch block provided can only catch UserNotFoundException. The main method will throw ArithmeticException when we try to devide by 0.
Since there is no catch block to catch this exception we will land up in fainally and then programm will terminate.

2.

package ExceptionTurorial;

public class UserNotFoundException{}

package ExceptionTurorial;

import java.io.File;
import java.io.IOException;

public class Test {

 public static void main(String[] args) {
  System.out.println("hi");
  throw new UserNotFoundException();
 }
}

1. Error at line throw new UserNotFoundException() due to no try catch provided.
2. Error at line throw new UserNotFoundException() since UserNotFoundException is not extending the Exception class

Answer : 2.
A custom Exception needs to entend the Exception class.

3.

package ExceptionTurorial;

public class UserNotFoundException extends Exception{}


package ExceptionTurorial;

public class Test {

 public static void main(String[] args) {
  System.out.println("hi");

  try {
   System.out.println("Hi");
   
  } catch (UserNotFoundException e) {
   e.printStackTrace();
  }
 }
}

1. No Error. Prints Hi
2. Error at catching UserNotFoundException as no such Exception is thwon in try block

Answer : 2.
UserNotFoundException is a checked Exception. So when we provide a catch block for it, there some be some could written to throw this Exception. Hence the compile time error. This is not applicable for RunTime Exception

4.

1. package ExceptionTurorial;
2. public class Test {
3. public static void main(String[] args) {
4.  System.out.println("hi");
5.  throw new UserNotFoundException();
6.  try {
7.     System.out.println("Hi");

8.  } catch (UserNotFoundException e) {
9.     e.printStackTrace();
10.  }
11. }
12. }

1. No Error. Prints Hi
2. Error at line 5. Since UserNotFoundException() is not catched

Answer : 2.
UserNotFoundException is thrown from outside the try block.

5.

1. package ExceptionTurorial;

2. public class Test {

3. public static void main(String[] args) {
4.  System.out.println("hi");
5.  try {
6.   System.out.println("Here");
7.   int j = 1 / 0;
8. 
9.   throw new UserNotFoundException();
10. 
11.  } catch (Exception e) {
12.   System.out.println("Caught");
13.   e.printStackTrace();
14.  } finally {
15.   System.out.println("in finally");
16.  }
17.  System.out.println("After catch");
18. }
19. }

1. Error on line 9. As No UserNotFoundException is caught

2. hi
Here
java.lang.ArithmeticException: / by zero
 at ExceptionTurorial.Test.main(Test.java:9)
Caught
in finally
After catch

Answer : 2.
As explained earlier. ArithmeticException will be thrown. Since we have provided a catch block to catch generic Exception. All Exceptions can be caught in it.

6.

1. package ExceptionTurorial;
2. public class Test {

3. public static void main(String[] args) {
4.  System.out.println("hi");
5.  try {
6.   System.out.println("Here");
7.   int j=1/0;
8.   throw new UserNotFoundException();

9.   }catch (UserNotFoundException e) {
10.     System.out.println("Caught UserNotFoundException");
11.     e.printStackTrace();
12.   }catch (ArithmeticException e) {
13.     System.out.println("Caught ArithmeticException");
14.     e.printStackTrace();
15.   } 
16.   finally{
17.     System.out.println("in finally");
18.   }
19.  System.out.println("After catch");
20.  }
21. }

hi
Here
java.lang.ArithmeticException: / by zero
 at ExceptionTurorial.Test.main(Test.java:10)
Caught ArithmeticException
in finally
After catch

Option 2
hi
Here
java.lang.ArithmeticException: / by zero
 at ExceptionTurorial.Test.main(Test.java:10)
Caught ArithmeticException
in finally

Answer : 2.
As explained earlier. ArithmeticException will be thrown. Since we have provided a catch block to catch ArithmeticException. That perticular catch block will execute.

7.

1. package ExceptionTurorial;

2. public class Test {
3. 
4. public static void main(String[] args) {
5.  System.out.println("hi");
6.  try {
7.   System.out.println("Here");
8.   int j = 1 / 0;
9.   throw new UserNotFoundException();
10. 
11.  } catch (Exception e) {
12.   System.out.println("Caught");
13.   e.printStackTrace();
14.  } catch (UserNotFoundException e) {
15.   System.out.println("Caught");
16.   e.printStackTrace();
17.  } finally {
18.  System.out.println("in finally");
19. }
20.  System.out.println("After catch");
21. }
22. 
23. }

1. hi
Here
java.lang.ArithmeticException: / by zero
 at ExceptionTurorial.Test.main(Test.java:9)
Caught
in finally
After catch
2. Error at line 14. UserNotFoundException already caught at catch block of Exception

Answer : 2.
When we define a generic catch block to catch all Exception, there is no need to define a special one.