At ISKLM z/OS startup, I get the following message:
Throwable occurred: java.security.KeyStoreException: KeyStore JCECCAKS
implementation not found
Diagnosing the problem
The above message will be found in the ISKLM joblog.
Resolving the problem
Have a look at your $JAVA HOME/lib/security/java.security file.
Check for anomalies, like maybe 2 security.provider.2 statements - this might occur for instance if you implemented a new level of java and forgot to renumber the remaining provider statements after the new java provider statement was added.
Correct the anomalies and restart ISKLM.