Java Exception constructors

I am attempting to get more detail about a particular cause of an exception surfaced to my application.

I am catching an ArrayIndexOutOfBoundsException. http://docs.oracle.com/javase/7/docs/api/java/lang/ArrayIndexOutOfBoundsException.html
That inherits RuntimeException which has a constructor accepting both a String and a Throwable cause.
http://docs.oracle.com/javase/7/docs/api/java/lang/RuntimeException.html#RuntimeException(java.lang.String,%20java.lang.Throwable)

So I attempt to catch the exception and add detail as I re-throw the exception:
        
catch(ArrayIndexOutOfBoundsException ex){
           throw new ArrayIndexOutOfBoundsException(String.format("Input was %s", Arrays.toString(value)),ex); 
}

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The String.format is working as expected.  Without the final ",ex", the code works OK, but I lose the information in the original Exception.  The code above does not compile.
no suitable constructor found for ArrayIndexOutOfBoundsException(java.lang.String,java.lang.ArrayIndexOutOfBoundsException)

Where is my mistake?

I'm using Java 7.

Thanks!
LVL 32
Daniel WilsonAsked:
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dpearsonCommented:
In this case ArrayIndexOutOfBoundsException itself only has 3 constructors and none of them take an exception as the second argument:

    public ArrayIndexOutOfBoundsException() {
        super();
    }
    public ArrayIndexOutOfBoundsException(int index) {
        super("Array index out of range: " + index);
    }
    public ArrayIndexOutOfBoundsException(String s) {
        super(s);
    }

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It doesn't inherit constructors from its base class.  They need to be defined in this class.

(You might ask why this class doesn't accept an exception as a second argument - I'd suspect the reason is that the second argument exception is meant to be an underlying cause, and ArrayIndexOutOfBoundsException isn't the result of something else happening, it's a primary cause of an exception.  In any case, it's a language choice - not something we can change).

You might want to try something like this instead:

		catch(ArrayIndexOutOfBoundsException ex){
			throw new IllegalArgumentException(String.format("Input was %s", Arrays.toString(value)),ex);
		}

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Doug
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Mark OlsenSr. DeveloperCommented:
Another option would be to call "initCause" after creating the exception and before throwing it. The cause could then be accessed when the exception is handled.

catch(ArrayIndexOutOfBoundsException ex){
   ArrayIndexOutOfBoundsException  arrayIndexOutOfBoundsException = 
      new ArrayIndexOutOfBoundsException(String.format("Input was %s", Arrays.toString(value)));
   arrayIndexOutOfBoundsException.initCause(ex);
   throw arrayIndexOutOfBoundsException;
}

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0
Daniel WilsonAuthor Commented:
Thank you both!
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