About Exception Handling

[ahmad razaa]

I have a confusion about this code.

public class MyClass3 {
public static void main(String[] args) {
    try {
        f();
    } catch (InterruptedException e) {
        System.out.println("1");
        throw new RuntimeException();
    } catch (RuntimeException e) {
        System.out.println("2");
        return;
    } catch (Exception e) {
        System.out.println("3");
    } finally {
        System.out.println("4");
    }
    System.out.println("5");
}
// InterruptedException is a direct subclass of Exception.
static void f() throws InterruptedException {
    throw new InterruptedException("Time for lunch.");
}
}

This code is giving the results:

1
4
Java.lang.RuntimeException

As we handled the RuntimeException , then why its throwing the exception and why its not run finally block?

Early answer will be appreciated.

[Edit: added code tags and indented code - Ankit]

[Hrishikesh Yeshwant Alshi]

For my own sanity:

public class MyClass3 { 
	public static void main(String[] args) { 
		try { 
			f(); 
		} catch (InterruptedException e) { 
			System.out.println("1"); 
			throw new RuntimeException(); 
		} catch (RuntimeException e) { 
			System.out.println("2"); 
			return; 
		} 

		catch (Exception e) { 
			System.out.println("3"); 
		} 

		finally { 
			System.out.println("4"); 
		} 
		System.out.println("5"); 
	} 
	// InterruptedException is a direct subclass of Exception. 
	static void f() throws InterruptedException { 
		throw new InterruptedException("Time for lunch."); 
	} 
} 

[Javin Paul]

Hi Yeshwant,

I have re formatted your code for better understanding

public class MyClass3 {
	public static void main(String[] args) {
		try {
			f();
		} catch (InterruptedException e) {
			System.out.println("1");
			throw new RuntimeException();
		} catch (RuntimeException e) {
			System.out.println("2");
			return;
		} catch (Exception e) {
			System.out.println("3");
		} finally {
			System.out.println("4");
		}
		System.out.println("5");
	}

	// InterruptedException is a direct subclass of Exception.
	static void f() throws InterruptedException {
		throw new InterruptedException("Time for lunch.");
	}
}

Here you see you have just one "try" block and all catch block and finally is for that only , there is no " try" block to catch RuntimeException and that's why its not getting caught and after printing what's there in finally its terminating.


If you modify code like below you will be able to catch RuntimeException.

public class MyClass3 {
	public static void main(String[] args) {
		try {
			f();
		} catch (InterruptedException e) {
			System.out.println("1");
			[size=18]try{
			throw new RuntimeException();
			}catch(RuntimeException rt){
				System.out.println("NOW IT MUST CATCH RUNTIME EXCEPTION");
                        }[/size]

		} catch (RuntimeException e) {
			System.out.println("2");
			return;
		} catch (Exception e) {
			System.out.println("3");
		} finally {
			System.out.println("4");
		}
		System.out.println("5");
	}

	// InterruptedException is a direct subclass of Exception.
	static void f() throws InterruptedException {
		throw new InterruptedException("Time for lunch.");
	}
}

Thanks
Javin

[Hrishikesh Yeshwant Alshi]

@ahmad razaa.

Javin explains it correctly.

@Javin,

This question was asked by ahmad razaa. I was about to post the same reply but you did it just before me. You explanation makes it very clear.