Java code Testing

I have few java packages in my workspace. I have made a change in one of the package's class. The change is addition of a new method. How should I go about checking whether the new change is backward compatible or not ? Should this be done as part of integration testing ?

I have added a value field to enum class and to extract the value field , I have added a getter method. Fyi, in the database enum's are being stored.

How should I go about this checking in the easiest possible way ?