I've followed a simple guide to constructing a workbook using Apache POI XSSF. Following the same guide I was able to WRITE an Excel sheet, however when attempting to read from one, I'm receiving the error displayed after the code.
Code:
try {
    FileInputStream file = new FileInputStream(new File("howtodoinjava_demo.xlsx"));
    // Create Workbook instance holding reference to .xlsx file
    XSSFWorkbook workbook = new XSSFWorkbook(file);
    // Get first/desired sheet from the workbook
    XSSFSheet sheet = workbook.getSheetAt(0);
    // Iterate through each rows one by one
    Iterator<Row> rowIterator = sheet.iterator();
    while (rowIterator.hasNext()) {
        Row row = rowIterator.next();
        // For each row, iterate through all the columns
        Iterator<Cell> cellIterator = row.cellIterator();
        while (cellIterator.hasNext()) {
            Cell cell = cellIterator.next();
            // Check the cell type and format accordingly
            switch (cell.getCellType()) {
            case Cell.CELL_TYPE_NUMERIC:
                System.out.print(cell.getNumericCellValue() + "t");
                break;
            case Cell.CELL_TYPE_STRING:
                System.out.print(cell.getStringCellValue() + "t");
                break;
            }
        }
        System.out.println("");
    }
    file.close();
} catch (Exception e) {
    e.printStackTrace();
}
Error output:
Exception in thread "main" java.lang.NoSuchFieldError: RAW_XML_FILE_HEADER at org.apache.poi.openxml4j.opc.internal.ZipHelper.verifyZipHeader(ZipHelper.java:179) at org.apache.poi.openxml4j.opc.internal.ZipHelper.openZipStream(ZipHelper.java:228) at org.apache.poi.openxml4j.opc.ZipPackage.(ZipPackage.java:93) at org.apache.poi.openxml4j.opc.OPCPackage.open(OPCPackage.java:294) at org.apache.poi.util.PackageHelper.open(PackageHelper.java:37) at org.apache.poi.xssf.usermodel.XSSFWorkbook.(XSSFWorkbook.java:273) at com.wtolliver.spring.test.ReadExcel.readExcel(ReadExcel.java:18) at com.wtolliver.spring.test.App.main(App.java:17)
 
     
     
     
     
     
    