In JDK-8309667, there were issues with debugging due to no logging or throwing of errors by X509KeyManagerImpl::getEntry. [Line](https://github.com/openjdk/jdk/blob/6a4c2676a6378f573bd58d1bc32b57765d756291/src/java.base/share/classes/sun/security/ssl/X509KeyManagerImpl.java#L243-L245)

Extra logging and error propagating should be implemented for the X509KeyManagerImpl.

Dot checking logic has to be changed, so no cases similar to .A should not trigger StringOutOfBounds exceptions.