null</br></br>java.lang.NullPointerException: Cannot invoke "String.compareTo(String)" because the return value of "th.co.skylogicsystem.skyframework.core.datalayer.XData.getS(String)" is null</br></br>Exception thrown from compare in class x.Sort$1 [on line number 52 of file Sort.java]</br></br>Exception thrown from binarySort in class java.util.TimSort [on line number -1 of file null]</br></br>Exception thrown from sort in class java.util.TimSort [on line number -1 of file null]</br></br>Exception thrown from sort in class java.util.Arrays [on line number -1 of file null]</br></br>Exception thrown from sort in class java.util.ArrayList [on line number -1 of file null]</br></br>Exception thrown from sort in class java.util.Collections [on line number -1 of file null]</br></br>Exception thrown from all in class x.Sort [on line number 47 of file Sort.java]</br></br>Exception thrown from all in class x.Sort [on line number 37 of file Sort.java]</br></br>Exception thrown from run in class RdclabAppointmentPackage214 [on line number 234 of file RdclabAppointmentPackage214.java]</br></br>Exception thrown from run in class java.lang.Thread [on line number -1 of file null]</br></br>