public class Enumerations { // All enumeration instances are interned; there should be no need for // an annotation. enum StudentYear { FRESHMAN, SOPHOMORE, JUNIOR, SENIOR; // check that receiver is OK @org.checkerframework.dataflow.qual.Pure public String toString() { return "StudentYear: ..."; } } public boolean isSophomore(StudentYear sy) { return sy == StudentYear.SOPHOMORE; } public boolean flow(StudentYear s) { StudentYear m = StudentYear.SOPHOMORE; return s == m; } }