why i have get such error nullpointerexception? - processing

Question

i want that if i pressed '1', '2' '3' '4' '5', img, img2, img3 img4 img5 is loading.
but when i ran this code, i have 'nullpointerexception error' and 'The file "e,jpg" is missing or inaccessible, make sure the URL is valid or that the file has been added to your sketch and is readable.'
but i make a folder and named 'data'. then i made photo in 'data' folder and named 'ejpg'.
i can't understand why i have error.
how can i solve that.
The code below is what I made.
PFont myFont;
PImage img, img2, img3, img4, img5;
void setup(){
size(500, 500);
img = loadImage("a,jpg");
img2 = loadImage("b,jpg");
img3 = loadImage("c,jpg");
img4 = loadImage("d,jpg");
img5 = loadImage("e,jpg");
}
void draw(){
if(keyPressed == true){
if(key == '1'){
image(img, 0, 0, width, height);
}
else if(key == '2'){
image(img2, 0, 0, width, height);
}
else if(key == '3'){
image(img3, 0, 0, width, height);
}
else if(key == '4'){
image(img4, 0, 0, width, height);
}
else if(key == '5'){
image(img5, 0, 0, width, height);
}
}
}

Answer 1

You've put commas before the file extensions ",jpg" and so the files can't be loaded and the loadImage(String) function returns null. These should be dots: a.jpg, b.jpg, ...
Unless you have a different way of naming the files, then you just need to make sure the paths match the actual filenames.

Answer 2

It's a simple naming convention issue. If you have named the files "a", "b", "c" etc then you should address them as "a.jpg", "b.jpg", "c.jpg" and so on. Note the use of full stop/periods rather than commas - if you get this wrong, the files won't load.
If you have literally titled an image "ajpg", you would have to address it as "ajpg.jpg".
One more thing to note is to make sure you are using the correct file extension. For example, double check that the images are in fact .jpg and not .png files. It's surprising how easily this can trip you up.