I have this `while` loop:

```
//All of this code is inside a for loop
positionUp = i - 1;

while ((positionUp > 0) && boardMatrix[positionUp][j] == boardMatrix[i][j]) {

    //do something

    positionUp--;
}

```

At some point, it is possible that `positionUp` it's assigned with the value `-1` (when `i=0`)

I thought that the `while`loop will stop at the first `false`evaluation thus not evaluating `boardMatrix[positionUp][j]` and not getting `java.lang.ArrayIndexOutOfBoundsException: -1`

I'm not seeing how can I solve this. Can someone point me in the way?