The Spring Expression Language (SpEL) currently cannot invoke a varargs MethodHandle function with an array, although that is supported for a varargs Method function.

Attempting to do so results in the array being supplied as a single argument to the MethodHandle.

For example, given a MethodHandle registered as a function named format that accepts (String, Object...), the SpEL expression #format('x', 'a', 'z') is supported, but the expression #format('x', new Object[]{'a', 'z'}) fails to evaluate since the MethodHandle is invoked with ('x', ['a', 'z']) whereas ('x', 'a', 'z') is required for a MethodHandle invocation.