The XML importer XSSFImportFromXML does not create new rows in any of the XSSFMap's related tables. Looking at the source code, it seems that new rows are created in the worksheet if necessary, but not to the table. The table never changes its size. After importing an XML document with repeating elements, only the first XML element is actually inside the table in the first row. All other elements are added below, outside of the table, to the worksheet.
I've created a pull request on Github: https://github.com/apache/poi/pull/99 Are pull request on Github ok or are patch files preferred? This is my first contribution for this project, if there are issues with the pull request I'll gladly try to improve it.
A PR on GitHub is perfectly fine!
fix merged using https://svn.apache.org/repos/asf/poi/trunk@1825315