IllegalArgumentException
class IllegalArgumentException extends RuntimeException
An argument was of the wrong kind or outside the range the function accepts. This is what most requireX guards throw.
Thrown by requireArray, requireInteger, requireNonEmpty.
Every class in this hierarchy takes an optional message, another exception whose message it reuses, or nothing at all. isException recognises all of them; a plain Error is not one.
Examples
Throwing and catching
throw new IllegalArgumentException("something specific about this call");
try {
doWork();
} catch (error) {
if (error instanceof IllegalArgumentException) {
// handled
}
}
See also
Source
23 September 2026
This documentation was generated with AI (Claude) from the library's source code.