WritableFont doesn’t like to be static!

While using the tool JExcelAPI within my Java application to generate Excel spreadsheets, I got the following exception:

java.lang.ArrayIndexOutOfBoundsException: 5
	at jxl.biff.IndexMapping.getNewIndex(IndexMapping.java:68)
	at jxl.biff.FormattingRecords.rationalize(FormattingRecords.java:388)
	at jxl.write.biff.WritableWorkbookImpl.rationalize(WritableWorkbookImpl.java:988)
	at jxl.write.biff.WritableWorkbookImpl.write(WritableWorkbookImpl.java:692)

It appears that this exception occurs only when you try to generate more than one Excel spreadsheet! How strange is that! 😯
After a bit of investigation, it seems that the problem comes from the use of the static modifier with a jxl.write.WritableFont variable.

I unfortunately don’t have the time to check the JExcelAPI code source to understand the root cause.
So my advice would be: “if you get EXACTLY the same stack trace, simply delete any static modifier you used with the WritableFont variables”. 🙂

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  1. #1 by GM Raj on 25 Jan 2011 - 14:35


    Thanks for this posting. Exactly after an year of this posting, I got benefited. This really helped me to overcome my one full day headache.

    Thanks again.

  2. #2 by remi on 01 Jul 2011 - 15:57

    THX a lot ! It works perfectly, just by removing static word (final is still OK).

  3. #3 by Mr. Me on 11 Apr 2013 - 16:27

    Thanks a lot! Works for me:-)

  4. #4 by wasttguy on 30 May 2013 - 15:28

    Thanks for this post, it looks like this problem is still an issue.
    As remi suggested, the problem seems to be the static modifier.

  5. #5 by Arjun Chandran on 11 Jun 2014 - 14:24

    Awesome suggestion.Helped me with an irritating issue.
    I had not made this WritableFont static but it was a global variable in my class.But it seems that for everynew font being used WritableFont need to newly instantiated.
    Anyways your suggestion helped me.

  6. #6 by Gaddy on 01 Jul 2015 - 13:21


    “also, it’s important that you Do Not declare your cell formats as static. As a cell format is added to a sheet, it gets assigned an internal index number. If you have two threads (such as in a Web environment) writing two different spreadsheets, the format numbers will get confused and the resulting sheet could either be corrupted or incorrect.”

  7. #7 by robin on 03 Sep 2015 - 13:27

    I thank you too. It works.
    Even four years after, this post continue to help

  8. #8 by Tom on 09 Dec 2015 - 10:41

    Saved a day for me!
    Had an hour to prepare Excel file export and got stuck on this exception.
    Everything works fine after having removed static modifier for NumberFormat.

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