Sometimes settings page results in the following error:
org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [java.util.List]: Specified class is an interface
It's because @ModelAttribute is used as a parameter for the getSettingsForm method, which is annotated with @ModelAttribute as well. It depends on the method invocation order of JVM if the parameter will be created before getSettingsForm. The parameter is not actually needed in the method so it can be safely removed.