The Problem (Q-score 13, ranked #105th of 303 in the Excel VBA archive)
The scenario as originally posted in 2009
I am looking to write to an excel (.xls MS Excel 2003 format) file programatically using Java. The excel output files may contain ~200,000 rows which I plan to split over number of sheets (64k rows per sheet, due to the excel limit).
I have tried using the apache POI APIs but it seems to be a memory hog due to the API object model. I am forced to add cells/sheets to the workbook object in memory and only once all data is added, I can write the workbook to a file! Here is a sample of how the apache recommends i write excel files using their API:
Workbook wb = new HSSFWorkbook();
Sheet sheet = wb.createSheet("new sheet");
//Create a row and put some cells in it
Row row = sheet.createRow((short)0);
// Create a cell and put a value in it.
Cell cell = row.createCell(0);
cell.setCellValue(1);
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
Clearly, writing ~20k rows(with some 10-20 columns in each row) gives me the dreaded “java.lang.OutOfMemoryError: Java heap space”.
I have tried increasing JVM initial heapsize and max heap size using Xms and Xmx parameters as Xms512m and Xmx1024. Still cant write more than 150k rows to the file.
I am looking for a way to stream to an excel file instead of building the entire file in memory before writing it to disk which will hopefully save a lot of memory usage. Any alternative API or solutions would be appreciated, but I am restricted to usage of java. Thanks! 🙂
Why this Range / Worksheet targeting trips people up
The question centers on reaching a specific cell, range, or workbook object. In Excel VBA, this is the #1 source of failures after activation events: every property (.Value, .Formula, .Address) behaves differently depending on whether the parent Workbook is explicit or implicit.
The Verified Solution — niche answer (below median) (+7)
Advisory answer — community consensus with reference links
Note: the verified answer below is a reference / advisory response rather than a copy-ready snippet.
Try to use SXSSF workbook, thats great thing for huge xls documents, its build document and don’t eat RAM at all, becase using nio
When to Use It — vintage (14+ years old, pre-2013)
Ranked #105th in its category — specialized fit
This pattern sits in the 98% tail relative to the top answer. Reach for it when your scenario closely matches the question title; otherwise browse the Excel VBA archive for a higher-consensus alternative.
What changed between 2009 and 2026
The answer is 17 years old. The Excel VBA object model has been stable across Office 2013, 2016, 2019, 2021, 365, and 2024/2026 LTSC, so the pattern still compiles. Changes that might affect you: 64-bit API declarations (use PtrSafe), blocked macros in downloaded files (Mark-of-the-Web), and the shift toward Office Scripts for web-first workflows.