I'm using Apache POI in my application to write data to an excel file. I've an excel file template and a few formulas are also there in it. In my application, i use the excel template, write into it ,then delete unused rows and calculate formulas in the end. I'm using SUM formula in the file. The problem is when rows are deleted, the SUM formula is not updating,due to which error values are coming up in excel. I'm using Apache POI in my application to write