public static SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

private static boolean isOverlap(String startdate1, String enddate1,String startdate2, String enddate2) {

Date leftStartDate = null;

Date leftEndDate = null;

Date rightStartDate = null;

Date rightEndDate = null;

try {

leftStartDate = format.parse(startdate1);

leftEndDate = format.parse(enddate1);

rightStartDate = format.parse(startdate2);

rightEndDate = format.parse(enddate2);

} catch (ParseException e) {

return false;

}

return

((leftStartDate.getTime() >= rightStartDate.getTime())

&& leftStartDate.getTime() < rightEndDate.getTime())

||

((leftStartDate.getTime() > rightStartDate.getTime())

&& leftStartDate.getTime() <= rightEndDate.getTime())

||

((rightStartDate.getTime() >= leftStartDate.getTime())

&& rightStartDate.getTime() < leftEndDate.getTime())

||

((rightStartDate.getTime() > leftStartDate.getTime())

&& rightStartDate.getTime() <= leftEndDate.getTime());

}