void () { myAnnotationSupports = AnnotationPackageSupport.EP_NAME.getExtensionList(); myDefaultNullables = StreamEx.of(myAnnotationSupports) .cross(s -> s.getNullabilityAnnotations(Nullability.NULLABLE).stream()).invert().toMap(); myDefaultNotNulls = StreamEx.of(myAnnotationSupports) .cross(s -> s.getNullabilityAnnotations(Nullability.NOT_NULL).stream()).invert().toMap(); myDefaultUnknowns = StreamEx.of(myAnnotationSupports) .cross(s -> s.getNullabilityAnnotations(Nullability.UNKNOWN).stream()).invert().toMap(); myDefaultAll = StreamEx.of(myDefaultNullables, myDefaultNotNulls, myDefaultUnknowns).toFlatList(Map::keySet); }