question: public String resolveURL ( String syncUrl , String registrationUrl ) { if ( StringUtils . isBlank ( syncUrl ) || syncUrl . startsWith ( Constants . PROTOCOL_NONE ) ) { log . debug ( "Using the registration URL to contact the remote node because the syncURL for the node is blank" ) ; return registrationUrl ; } try { URI uri = new URI ( syncUrl ) ; for ( ISyncUrlExtension handler : extensionService . getExtensionPointList ( ISyncUrlExtension . class ) ) { syncUrl = handler . resolveUrl ( uri ) ; uri = new URI ( syncUrl ) ; } } catch ( URISyntaxException e ) { log . error ( e . getMessage ( ) , e ) ; } return syncUrl ; }
target:  Build the url for remote node communication. Use the remote sync_url first, if it is null or blank, then use the registration url instead.