//Instantiating a Workbook object
Workbook workbook = new Workbook();

//Adding a new worksheet to the Workbook object
WorksheetCollection worksheets = workbook.getWorksheets();
Worksheet worksheet = worksheets.add("My Worksheet");

Cells cells = worksheet.getCells();

//Adding some value to cell
Cell cell = cells.get("A1");
cell.setValue("This is Aspose test of fonts!");

//Saving the Excel file
workbook.save("data/xlsx4j/newWorksheet_Aspose.xls");

public static void main(String[] args) throws Exception {

    String outputfilepath = "data/xlsx4j/newWorksheet_Xlsx4j.xlsx";

    SpreadsheetMLPackage pkg = SpreadsheetMLPackage.createPackage();

    WorksheetPart sheet = pkg.createWorksheetPart(new PartName("/xl/worksheets/sheet1.xml"), "Sheet1", 1);

    addContent(sheet);

    SaveToZipFile saver = new SaveToZipFile(pkg);
    saver.save(outputfilepath);

    System.out.println("\n\n done .. " + outputfilepath);   
}

private static void addContent(WorksheetPart sheet) {

    // Minimal content already present
    SheetData sheetData = sheet.getJaxbElement().getSheetData();

    // Now add
    Row row = Context.getsmlObjectFactory().createRow();
    Cell cell = Context.getsmlObjectFactory().createCell();
    cell.setV("1234");
    row.getC().add(cell);

    row.getC().add(createCell("hello world!"));

    sheetData.getRow().add(row);
}

/**
    // Note: if you are trying to add characters, not a number,
    // the easiest approach is to use inline strings (as opposed to the shared string table).
    // See http://openxmldeveloper.org/blog/b/openxmldeveloper/archive/2011/11/22/screen-cast-write-simpler-spreadsheetml-when-generating-spreadsheets.aspx
    // and http://www.docx4java.org/forums/xlsx-java-f15/cells-with-character-values-t874.html
 */
private static Cell createCell(String content) {

    Cell cell = Context.getsmlObjectFactory().createCell();

    CTXstringWhitespace ctx = Context.getsmlObjectFactory().createCTXstringWhitespace();
    ctx.setValue(content);

    CTRst ctrst = new CTRst();
    ctrst.setT(ctx);

    cell.setT(STCellType.INLINE_STR);
    cell.setIs(ctrst); // add ctrst as inline string

    return cell;

}