`spring-core` is an `optional` dependency of `spring-security-crypto`,
so it is not published in the POM and is not guaranteed to be on the
classpath when the module is used standalone.
7.1.0 refactored `AbstractValidatingPasswordEncoder` to use
`org.springframework.util.StringUtils#hasLength`, which causes
`NoClassDefFoundError` on `BCryptPasswordEncoder#matches` (and other
encoders extending it) for standalone users.
Restore the inline null/empty checks the encoder used prior to that
refactor so that the runtime hot path no longer reaches into
`spring-core`.
Closes gh-19317
Signed-off-by: seonwoo_jung <laborlawseon@kap.kr>
seonwoo_jung
7cc20776c1