import org.apache.poi.xssf.usermodel.XSSFSheet

import org.apache.poi.xssf.usermodel.XSSFWorkbook

FileInputStream file = new FileInputStream (new File("E:\\Testdata.xlsx"))

XSSFWorkbook workbook = new XSSFWorkbook(file);

XSSFSheet sheet = workbook.getSheetAt(0);

'Read data from excel'

String Data_fromCell=sheet.getRow(1).getCell(1).getStringCellValue();

'Write data to excel'

sheet.getRow(1).createCell(1).setCellValue("Mahesh2");

file.close();

FileOutputStream outFile =new FileOutputStream(new File("E:\\Testdata.xlsx"));

workbook.write(outFile);

outFile.close();