package test; import java.util.*; public interface TwoSuperclassesInvariantAndCovariantInferMutability { public interface Super1 { List<List<String>> foo(); void dummy(); // to avoid loading as SAM interface } public interface Super2 { List<List<String>> foo(); void dummy(); // to avoid loading as SAM interface } public interface Sub extends Super1, Super2 { List<List<String>> foo(); } }