Fix NPE when API has not yet been defined.

[karelmaxa]

I have fixed the NullPointerException in SmsRequestHandler when the api is not defined yet. Related stacktrace:

ERROR: SMSNotificationManager.objectChanged Exception for class: org.forgerock.openam.core.rest.sms.SmsRequestHandler
java.lang.NullPointerException: Cannot invoke "org.forgerock.api.models.ApiDescription.equals(Object)" because "oldApi" is null
	at org.forgerock.openam.core.rest.sms.SmsRequestHandler.notifyDescriptorChange(SmsRequestHandler.java:832)
	at org.forgerock.openam.core.rest.sms.SmsRequestHandler.refreshServiceRoute(SmsRequestHandler.java:355)
	at org.forgerock.openam.core.rest.sms.SmsRequestHandler.objectChanged(SmsRequestHandler.java:324)
	at com.sun.identity.sm.SMSNotificationManager.sendNotifications(SMSNotificationManager.java:294)
	at com.sun.identity.sm.SMSNotificationManager$LocalChangeNotifcationTask.run(SMSNotificationManager.java:370)
	at org.forgerock.openam.audit.context.AuditRequestContextPropagatingRunnable.run(AuditRequestContextPropagatingRunnable.java:42)
	at com.iplanet.am.util.ThreadPool$WorkerThread.run(ThreadPool.java:314)

[pavelhoral]

LGTM

[pavelhoral]

On a second look there are few suspicious things in that class:

There are locks being used when accessing route routeTree property and there are no locks when working with apiListeners. There is even apparent inconsistency between #removeDescriptionListener and synchronized #notifyDescriptionChange. Seems to be ConcurrentModificationException hiding in there.

@karelmaxa can you please confirm that there is no synchronization issue here?

[pavelhoral]

Ty for the changes.