Question

I would like to define some constants like #define myXYZ 1 so I can also use them in switch statements.

When I do the often suggested

public static final Integer myXYZ = 1;

and

case Constants.myXYZ:

I get the compiler message that case expression must be constant

What would be the best way of resolving this?

Thanks!

Answer 1

Just change it to int and it should be fine:

public static final int myXYZ = 1;

This is because a case value has to be a constant expression or an enum name. From section 15.28 of the JLS (constant expressions):

A compile-time constant expression is an expression denoting a value of primitive type or a String that does not complete abruptly and is composed using only the following […]

Therefore an expression of type int can be a constant expression, but an expression of type Integer can’t.

If this is a set of values which makes sense as a concept on its own, then an enum would possibly make more sense.