in src/main/java/org/apache/sling/commons/scheduler/impl/WhiteboardHandler.java [187:196]
void register(final ServiceReference<?> ref, final Object job) {
try {
if (!tryScheduleExpression(ref, job) && !trySchedulePeriod(ref, job)) {
this.logger.debug("Ignoring service {} : no scheduling property found.", ref);
}
} catch ( final IllegalArgumentException iae) {
this.logger.warn("Ignoring service {} : {}", ref, iae.getMessage());
}
}