IndexOutOfBoundsException is a subclass of RuntimeException mean it is an 
unchecked exception which is usally thrown to indicate that an index of some 
sort (such as to an array, to a string, or to a vector) is out of range.e.g 
using List.
You can check it here:
https://stackoverflow.com/questions/40006317/what-is-indexoutofboundsexception-how-can-i-fix-it