@Override
        public AppConfigurationEntry[] getAppConfigurationEntry(String name) {
            var options = new HashMap<String, String>();
            options.put("useKeyTab", "true");
            options.put("keyTab", this.keyTabLocation);
            options.put("principal", this.servicePrincipalName);
            options.put("storeKey", "true");
            options.put("doNotPrompt", "true");
            if (this.debug) {
                options.put("debug", "true");
            }
            options.put("isInitiator", "false");

            return new AppConfigurationEntry[]{new AppConfigurationEntry("com.sun.security.auth.module.Krb5LoginModule",
                AppConfigurationEntry.LoginModuleControlFlag.REQUIRED, options),};
        }
Normally you need a JAAS config file in order to use the JAAS Kerberos Login Module,
with this class it is not needed and you can have different configurations in one JVM.
pac4j-kerberos/src/main/java/org/pac4j/kerberos/credentials/authenticator/SunJaasKerberosTicketValidator.java