Java中此ArrayIndexOutOfBoundsException的原因是什么？

Question

Java throws an ArrayIndexOutOfBoundsException error when I run this function:

public int[] copySecondSlice(int[] array) {
    int[] newArray = new int[array.length/2];
    for (int i = array.length/2; i < array.length; i++) {
        assert i == 1;
        newArray[i] = array[i];
    }
    return newArray;
}

I tried multiple assets to check that i is superior to 0 and inferior to my array's length, but nothing does the trick. Could someone help me understand my mistake here?

Answer 1

Simply because you are trying to reach the index which is out of bound of array new Array.

See

int[] newArray = new int[array.length/2];

Here you declare length of newArray is array.length/2

And

for (int i = array.length/2; **i < array.length**; i++) {
 newArray[**i**] = array[i];

Your condition will allow for to iterate till array.length-1 so newArray is supposed to fill till that index ie array.length-1 . But our length of newArray is only array.length/2 so it is going out of bound.

as @RP said you can correct it.

newArray index should start from 0 instead of i . Something like

  for (int j=0, i = array.lenght/2; i < array.length; i++, j++) { 
       ...
       newArray[j] = array[i];