optaplanner-examples/src/main/java/org/optaplanner/examples/flightcrewscheduling/domain/Flight.java
public boolean overlaps(Flight other) {
        return departureUTCDateTime.compareTo(other.arrivalUTCDateTime) < 0
            && other.departureUTCDateTime.compareTo(arrivalUTCDateTime) < 0;
    }
public boolean overlaps(Flight other) {
        return departureUTCDateTime.compareTo(other.arrivalUTCDateTime) < 0
            && other.departureUTCDateTime.compareTo(arrivalUTCDateTime) < 0;
    }
TODO return overlapping time to avoid score trap?