XLSReader doesn't close the workbook

[Fagner Fonseca]

My application is locking the xlsx file and I don't know where. My application closes the InputStream and I coudn't find any place in my code where the resource isn't released. This problem doesn't happen always. The problem happens sometimes and I'm not able to reproduce it when I want. It seems that XLSReader doesn't close the workbook and maybe this is the cause of the problem. I have seen in some questions of the stackoverflow that the workbook also must be closed.

I made a question in the stackoverflow about this and a member told me this is a bug: https://stackoverflow.com/questions/47419283/does-the-xlsreader-from-jxls-close-the-workbook