Slot overlapping is mot working for Date slots

Question

The data type is the "Date" for all the variables.

if (slotStartTime.before(preBookedSlot.getSlotStartTime())
                                && slotEndTime.after(preBookedSlot.getSlotStartTime())
                                || slotStartTime.before(preBookedSlot.getSlotEndTime())
                                        && slotEndTime.after(preBookedSlot.getSlotEndTime())
                                || slotStartTime.before(preBookedSlot.getSlotStartTime())
                                        && slotEndTime.after(preBookedSlot.getSlotEndTime())
                                || slotStartTime.after(preBookedSlot.getSlotStartTime())
                                        && slotEndTime.before(preBookedSlot.getSlotEndTime()))
 {
                            overlap = true;
}

Can you pls help me here slots time is getting overlapped but still i am not able to go inside if block