Null safety annotations
The @NotNullByDefault annotation marks all fields, methods and parameters in a class or package @NotNull, so Android Studio will warn if values that may be null are used. Please use this annotation for new classes, and specify @Nullable for any fields, methods and parameters that may be null.
Injected fields are initialised to null, so injected classes should use @MethodsNotNullByDefault and @ParametersNotNullByDefault, or specify @Nullable for injected fields.