In CertificateMessage.java, the log message printed at https://github.com/openjdk/jdk/blob/e01cd7c3ed923cd19509fc972ba6e4aa2991289f/src/java.base/share/classes/sun/security/ssl/CertificateMessage.java#L1049 is incorrect. It only means a key algorithm is already checked, not that it's unsupported.