I had imported the same XLS file many times without any problems (each time slightly modified - it is something like an externally maintained setup table; yes it is ugly ;-)
But after deleting an unused sheet (a pivot table) SQuirreL started to throw "An error occurred while reading import file data." after selecting the sheet name to import.
I am using LibreOffice for editing the XLS file, saving as XLSX didn't help either.
(Saving as CSV helped - but that would not be practical doing every time for the import.)
The problem went finally away after copy&pasting the whole sheet into a fresh XLS file.
Using SQuirreL 4.2.0 on Windows 8.1 with AdoptOpenJDK 11.0.10+9
The attachments are the trimmed down versions that still throw the error.
(LibreOffice never had any problems opening any of the versions.)
Last log entry:
Logged by net.sourceforge.squirrel_sql.plugins.dataimport.action.ImportTableDataCommand at 03/09/2021, 23:39:
execute: unexpected exception - Array index out of range: 1
Fixed in our GIT repository. Will be available in future snapshots and versions.
Excerpt from change log:
'#1486 Excel import failed with ArrayIndexOutOfBoundsException
when a sheet contained rows with more cells than the first row.