Got some funky shit going on

Java keeps throwing this error at me all of a sudden: com.android.phone.MSimPhoneInterfaceManager is not abstract and does not override abstract method getAllCellInfo() in com.android.internal.telephony.msim.ITelephonyMSim
public class MSimPhoneInterfaceManager extends ITelephonyMSim.Stub {

I have not a damn clue on how to fix it, so here is my humble attempt at doing so. Let's just hope it's not a disaster