Exception in thread java.lang.ArrayIndexOutOfBoundsException: 5

I'm a newbie who is trying to complete the below tutorial

    // Create a method called countEvens
    // Return the number of even ints in the given array. 
    // Note: the % "mod" operator computes the remainder, e.g. 5 % 2 is 1. 
/*
 * SAMPLE OUTPUT:
 *  
 * 3
 * 0
 * 2
 *  
 */

Below is my code

public static void main(String[] args) {

        int a[] = {2, 1, 2, 3, 4};
         countEvens(a); // -> 3
         int b[] = {2, 2, 0};
         countEvens(b); // -> 3
         int c[] = { 1, 3, 5};
         countEvens(c); // -> 0

    }


    public static void countEvens(int[] x){
        int i = 1;
        int count = 0;
        while ( i <= x.length){
            if (x[i] % 2 == 0){
                count ++;
            }
            i ++;
        }
        System.out.println(count);
    }

The code can be run, but I get the below error message

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5
    at apollo.exercises.ch05_conditionals.Ex5_CountEvens.countEvens(Ex5_CountEvens.java:23)
    at apollo.exercises.ch05_conditionals.Ex5_CountEvens.main(Ex5_CountEvens.java:10)

May I know what I'm doing wrong here?