Hey guys, I'm having an issue for the following sn...

# getting-started

[chi]

Hey guys, I'm having an issue for the following snippets. One crashes, the other doesn't crash.

val bufferedImgFile: BufferedImage = ImageIO.read(File(filePath))
val imageMatrix: Array<IntArray> = Array(height) { IntArray(width) }
(0..(bufferedImgFile.height - 1)).map { hgt ->
        (0..(bufferedImgFile.width - 1)).map { wdt ->
          imageMatrix[hgt][wdt] = bufferedImgFile.getRGB(hgt, wdt)
        }
      }

And

val bufferedImgFile: BufferedImage = ImageIO.read(File(filePath))
val imageMatrix: Array<IntArray> = Array(height) { IntArray(width) }
async {
        (0..(bufferedImgFile.height - 1)).map { hgt ->
          async {
            (0..(bufferedImgFile.width - 1)).map { wdt ->
              data[hgt][wdt]= bufferedImgFile.getRGB(hgt, wdt)
            }
          }
        }
      }

The former would crash with an ArrayOutOfBoundsException, the later doesn't crash and completes. Please why is this so?

[Andreas Sinz]

Where does the async function come from? Anko? Coroutines?

[chi]

Coroutines

[Andreas Sinz]

Ok, so the reason you don't get an exception here is that async catches Exceptions and puts it into the returned Deferred

[Andreas Sinz]

if you use async { ... }.await() the same exception should be thrown

[chi]

Aha! Thanks for that.
Please one more thing. The dimensions of the buffered image is 960 by 828, from the definition for BufferedImage.getRGB it says the An ArrayOutOfBoundsException may be thrown if the coordinates are not in bounds
GIven the dimensions, am I supposed to be getting this error?

[Andreas Sinz]

@chi the function is defined as getRGB(x: Int, y: Int), so it expects the horizontal coordinate as the first parameter, you flipped them

[chi]

Gracias for the observation!

[philipharder]

so I'm still learning... where does data come from in the second snippet? data[hgt][wdt]=bufferedImgFile.getRGB(hgt,wdt)

[chi]

@philipharder, I made a mistake there, it was supposed to be
imageMatrix[hgt][wdt]= bufferedImgFile.getRGB(hgt, wdt)