Bug 65572

the current XSSFWorkbook has this code

```
        // YK: Mimic Excel and silently truncate sheet names longer than 31 characters
        if(sheetname.length() > 31) {
            sheetname = sheetname.substring(0, 31);
        }
```

I'll try removing this

Actually, I currently only have access to hosted Excel on Sharepoint and it rigidly enforces a 31 char limit on worksheet names - so no, I don't think it is a good idea to remove this in POI.

Maybe what we need is to throw an exception if someone tries to use a 32 or more char sheet name.

the existing behaviour is clearly documented in the Javadocs.

```
     * Note that Excel allows sheet names up to 31 chars in length but other applications
     * (such as OpenOffice) allow more. Some versions of Excel crash with names longer than 31 chars,
     * others - truncate such names to 31 character.
     * <p>
     * POI's SpreadsheetAPI silently truncates the input argument to 31 characters.
     * Example:
     *
     * <pre>{@code
     * Sheet sheet = workbook.createSheet("My very long sheet name which is longer than 31 chars"); // will be truncated
     * assert 31 == sheet.getSheetName().length();
     * assert "My very long sheet name which i" == sheet.getSheetName();
     * }</pre>
```

Also this:

```
     * See {@link WorkbookUtil#createSafeSheetName(String nameProposal)}
     *      for a safe way to create valid names
```

Closing as invalid