Outofbounds exception on empty ArrayList

Question

I'm getting an outofbounds exception from the following code:

myArray.get(myArray.size() -  1)

I know it's due to the fact that myArray contains no items. I tried adding this before checking for the last added item in the array:

If (myArray.size()  == -1){ myArray.add(string) }

But that didn't make any difference. What am I doing wrong?

Why do you think size() returns -1 when it's empty?

rgettman
– rgettman

2014-04-10 23:03:17 +00:00
Commented Apr 10, 2014 at 23:03 — rgettman
– rgettman, Commented Apr 10, 2014 at 23:03

Ennosigaeon · Accepted Answer · 2014-04-10 23:10:46Z

2

Try to use

if (!myArray.isEmpty())
    myArray.get(myArray.size() -  1);

This will get the last value in the list, when the list isn't empty.

answered Apr 10, 2014 at 23:10

Ennosigaeon

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Comments

amit · Accepted Answer · 2014-04-10 23:03:55Z

1

myArray.size() will never be -1. Note that size is a non-negative number. It can be 0 or more.

You can check if it equals 0 and then add element.

answered Apr 10, 2014 at 23:03

amit

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2 Comments

Grux Over a year ago

I was under the impression that the first position in the array is 0, that's why I was checking for -1.

Boann Over a year ago

@Josh The first position in the array is 0, but the numbering scheme of the elements has no bearing on the total number of elements. The size of an empty array is 0 because there are 0 things in it. End of.

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