I use POI Apache Java libraries to read and write Excel files. I need to produce very large Excel files: some 20000 lines and around 40 columns.
The POI Apache Excel functions write the whole file in memory (somewhere) before writing it to the file. After around 12000 lines produced, I get a java.lang.OutOfMemoryError: Java heap space.
Even if I cut down my program to write 1000 lines at a time (open the Excel file, write data, close the file), I still get the same error after writing around 120000 lines.
I tried the 'java' SETUP 'vmoptions' using different combinations of Xms and Xmx and the results were the same. I quit APLX before each try.
Any hints ?