java.lang.ClassNotFoundException: org.apache.xmlbeans.XmlOptions

Je suis en train d'utiliser POI dans un servlet pour traiter un fichier téléchargé en tant que fichier Excel:

public static String readExcel(InputStream inp) {
    //InputStream inp = null;
    StringBuilder excelDataBuilder = new StringBuilder();
    try {
        Workbook wb = WorkbookFactory.create(inp);
        Sheet sheet = wb.getSheetAt(0);
        Header header = sheet.getHeader();

        int rowsCount = sheet.getLastRowNum();
        for (int rowCounter = 0; rowCounter <= rowsCount; rowCounter++) {
            Row row = sheet.getRow(rowCounter);
            int colCounts = row.getLastCellNum();
            for (int colCounter = 0; colCounter < colCounts; colCounter++) {
                Cell cell = row.getCell(colCounter);
                excelDataBuilder.append(cell.getStringCellValue());
                if (colCounter < colCounts)
                    excelDataBuilder.append(",");
            }
            if (rowCounter <= rowsCount) {
                excelDataBuilder.append("\n");
            }
        }
        return excelDataBuilder.toString();

    } catch (Exception ex) {
        LOG.error("Exception", ex);
    } finally {
        try {
            inp.close();
        } catch (IOException ex) {
            LOG.error("IOException", ex);
        }
    }
    return excelDataBuilder.toString();
}

Cependant, il a jeté une exception à la ligne suivante:

Workbook wb = WorkbookFactory.create(inp);

Voici la Trace de la Pile:

SEVERE: Servlet.service() for servlet [com.bhrt93.excel.servlet.UploadProcessExcel] in context with path [/ExcelServletProcessCommons] threw exception [Servlet execution threw an exception] with root cause
java.lang.ClassNotFoundException: org.apache.xmlbeans.XmlOptions
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
at org.apache.poi.POIXMLDocumentPart.<clinit>(POIXMLDocumentPart.java:59)
at org.apache.poi.ss.usermodel.WorkbookFactory.create(WorkbookFactory.java:78)
at com.bhrt93.excel.service.ExcelReaderService.readExcel(ExcelReaderService.java:22)
at com.bhrt93.excel.servlet.UploadProcessExcel.doPost(UploadProcessExcel.java:69)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)

Comment est-il la cause et comment puis-je le résoudre?