The value null

The value null is a reserved word, not a string. When used in place of an object belonging to an imported Java™ class, it has the same meaning as it does in the Java language.

Do not use null to signify an empty string. To signify an empty string, use a pair of single quotes ('') in the advanced macro format, or nothing at all in the basic macro format. If you use the value null in a string context (for example, by assigning it to a string variable), then the macro editor or the macro runtime will convert the value null to the string 'null'.