InputStream inStream = new FileInputStream("workbook.xls");
Workbook workbook = WorkbookFactory.create(inStream);

Sheet sheet = workbook.createSheet("new sheet");
sheet.autoSizeColumn(0); //adjust width of the first column
sheet.autoSizeColumn(1); //adjust width of the second column

FileOutputStream fileOut;
fileOut = new FileOutputStream("AutoFit_Apache.xls");
workbook.write(fileOut);
fileOut.close();

Workbook workbook = new Workbook("workbook.xls");

//Accessing the first worksheet in the Excel file
Worksheet worksheet = workbook.getWorksheets().get(0);

worksheet.autoFitRow(1); //Auto-fitting the 2nd row of the worksheet
worksheet.autoFitColumn(0); //Auto-fitting the 1st column of the worksheet

//Saving the modified Excel file in default (that is Excel 2003) format
workbook.save("AutoFit_Aspose.xls");