Error : java.util.ConcurrentModificationException

Question

i have a grid from where users select the row , when a row is clicked then its id is sending to my action class AddBookToSession.java and after wards it is retu

Answer 1

It is possible that the page is refreshed around the time your code executes "books.add(book);" in which case you will get the exception as you are modifying a collection at same time someone else is using it.

Is it possible to modify your code so that the "books" you modify in the AddBookToSession is copy of the internal list of books.

books = new ArrayList((ArrayList) session.get(BillTransactionBooksConstants.BOK););