Can you index an array with a long int?

Question

Is it somehow possible to use a long int to index an array? Or is this not allowed?

What I mean is bellow in the code.

long x = 20;
char[] array = ne         


        

Answer 1

No, it's not possible. JLS 15.10 states that the expression in an array initializer must be promoted to an int:

Each dimension expression undergoes unary numeric promotion (§5.6.1). The promoted type must be int, or a compile-time error occurs.

Same thing with applies to array access expressions (JLS 15.13):

The index expression undergoes unary numeric promotion (§5.6.1). The promoted type must be int, or a compile-time error occurs.

If you want to use a long, you'll have to cast it to int first:

char[] array = new char[(int) x];
res = array[(int) x];