logger field of AbstractRememberMeServices class returns null when extending PersistentTokenBasedRememberMeServices in spring security

Question

I need to extend PersistentTokenBasedRememberMeServices class to override some methods of it. but when I add any method in my new class (ExtendedPersistentTokenBasedRememberMeServices), the logger in autoLogin method of AbstractRememberMeServices causes null pointer exception in process of authenticating user with rememberMe token. (PersistentTokenBasedRememberMeServices class extends AbstractRememberMeServices in spring security)

why this is happening? Any assistance you can provide would be greatly appreciated.