A component of an array is accessed by an array access expression (§15.12) that
consists of an expression whose value is an array reference followed by an indexing expression enclosed by [ and ], as in A[i]. All arrays are 0-origin. An array
with length n can be indexed by the integers 0 to n-1.
Arrays must be indexed by int values; short, byte, or char values may also be used as index values because they are subjected to unary numeric promotion (§5.6.1) and become int values. An attempt to access an array component with a long index value results in a compile-time error.
All array accesses are checked at run time; an attempt to use an index that is less than zero or greater than or equal to the length of the array causes an IndexOutOfBoundsException to be thrown.