Thread: Experiment gone wrong . . . exception in class

Ok, so I was just goofing off, creating a class that allowed you to pass in an array,
and pass in the two positions that you want to swap, and then return the array,
it's just a jackass solution, but it is just an experiment anyway. My question
doesn't really relate directly to the array-swapping anyway. After creating the swap
routine, I got to thinking about it, and realized that passing in position parameters
would require error checking, so, having not ever written a custom throw statement,
I decided I would give it a whirl . . . . and it's about half-right, but I am now stuck,
because the class is suppose to return the array, but when I throw the custom error,
I can't seem to return the array!

So the real issue is, if you create a class that returns something, but need to add
error checking, how do you accomplish returning it? The code below throws an
error - "This method must return a result of type int[]"

public class ArraySwapElements {
	/**  swap elements in an array
	 * @param int[] values
	 * @param position1
	 * @param position2
	 * @return values[] 
	 * */
 
	public static int[] swapElements(int[] values, int position1, int position2) {
		try{
		if(position1 < 0  || position1 > values.length -1 || position2 < 0  || position2 > values.length -1)
			throw new ArrayException();
		int temp = values[position1];
		values[position1] = values[position2];
		values[position2] = temp;
		return values;
		} catch(ArrayException ae){
			System.out.println("Parameter position1 or parameter position2 out of bounds.");
		}
	} 
 
	@SuppressWarnings("serial")
	class ArrayException extends Exception  {
	      //Parameterless Constructor
	      public ArrayException() {}
 
	      //Constructor that accepts a message
	      public ArrayException(String message)
	      {
	         super(message);
	      }
	 }
}

That makes sense . . . . I'll give it a whirl. Thanks.

Later note:
Just in case anyone wants to see what I cooked up from this:

public static int[] swapElements(int[] values, int position1, int position2) throws ArrayIndexOutOfBoundsException{
		if(position1 < 0  || position1 >= values.length || position2 < 0  || position2 >= values.length){
			throw new ArrayIndexOutOfBoundsException();
		}
		int temp = values[position1];
		values[position1] = values[position2];
		values[position2] = temp;
		return values;
		}
	}

Two big changes:
1. Did away with the custom error; ArrayIndexOutOfBoundsException already exists, why not use it.
2. Removed the magic numbers, -1 from the code

position1 >= values.length

by inserting an equals sign instead.

You could've also moved the return statement outside of the try/catch block