!

is a single, slender character that’s easier to gloss over than

not

is

It’s hard to follow if you have

!

on start of long expression or chain of calls So

not

as part of last call is more natural to read, compare

!something.isNullOrBlank()

=

not something is null or blank

and

something.isNotNullOrBlank()

=

something is not null or blank

not

as postfix also work, but reads not so naturally:

something.isNullOrBlank().not()

=

something is null or blank not

for sure, we’re on the same page