Workaround for bug 52233 (IndexOutOfBounds on getColumnWidth after saving)

[Stuart Owen <so...@cs.manchester.ac.uk>]

Hi,
     I've been looking again into a bug I raised a while ago 
https://issues.apache.org/bugzilla/show_bug.cgi?id=52233
     I can confirm this still occurs in POI 3.8, and only affects the 
workbook stored in memory (its fine if the saved workbook is reloaded). 
The root of the problem appears to be the call to ColumnHelper.getColumn 
after the save.
     However, I've found that by calling 
workbook.getSheet(x).getColumnHelper().cleanColumns(); solves the 
problem for me - after this call the getColumn and getColumnWidth work 
as expected. I'm not entirely sure what the purpose of that method is, 
since it has no documents in the javadoc.

     So, is this a safe work around for this bug?
     I hoping to get some time next week to see if I can fix the bug 
itself, any pointers would help me in this.

regards,
Stuart Owen
<https://issues.apache.org/bugzilla/show_bug.cgi?id=52233>