I am having this problem too. I tried the 2.02 and 2.01. I get errors elsewhere in the code. It gives an error on cfg.isInitialized -- unknown member.
The following line also gives an error:
cfg.Defaults(CreateMap("RB_Launch_Count": 3, "loading_phrase": "Hallo world!"))
Property: Defaults is writeonly.
Anyway, I get this error after commenting out the above.
java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.firebase.remoteconfig.FirebaseRemoteConfig com.google.firebase.remoteconfig.RemoteConfigComponent.get(java.lang.String)' on a null object reference
Please post the Java code. I'm no Java expert, but I will take a look.