public boolean removeColumn(String sheetName, int colNum) {
		try{
		if(!isSheetExist(sheetName))
			return false;
		fis = new FileInputStream(path); 
		workbook = new XSSFWorkbook(fis);
		sheet=workbook.getSheet(sheetName);
		XSSFCellStyle style = workbook.createCellStyle();
		style.setFillForegroundColor(HSSFColor.GREY_40_PERCENT.index);
	//	XSSFCreationHelper createHelper = workbook.getCreationHelper();
		style.setFillPattern(HSSFCellStyle.NO_FILL);
		
	    
	
		for(int i =0;i<getRowCount(sheetName);i++){
			row=sheet.getRow(i);	
			if(row!=null){
				cell=row.getCell(colNum);
				if(cell!=null){
					cell.setCellStyle(style);
					row.removeCell(cell);
				}
			}
		}
		fileOut = new FileOutputStream(path);
		workbook.write(fileOut);
	    fileOut.close();
		}
		catch(Exception e){
			e.printStackTrace();
			return false;
		}
		return true;
		
	}