Why there's so much of memory consumption when reports are generated using JasperReports-library and why that graph does not go down once report generation is complete?

[archana.learnings]

Why there's so much of memory consumption when reports are generated using JasperReports-library and why that graph does not go down once report generation is complete?

1. I've attached 2 jconsole Heap size graphs here, 

1 , In  this Jconsole memory graph which used Jasper report library in application deployed in wildlfy. In this I observed that even after report generation was complete memory was not getting reclaimed i.e. graph was not going down.. In this I've not used virtulizer but I've tried all 3 virtuliers but even with that I have not seen memory going down immeditly after report completion. However memory consumed was 1 or 2 gb lesser than with virtuliers but memory did not go down immediatly after report execution was done even when virtulizers were used like it was going down a lot almost as it was at start of report execution when reports were executed using Jasper server. This is jconsole of Wildfly as I'm using jasper reports library for generating report.

2. Interestingly in image, memory graph taken using jconsole for jasper server, in this you can see that memory is going down immediately after report generation is done.

What change is required or what I might have missed because of which memory which got spiked during execution remain there and with each request it went up piling up and up ?

I also obsvered that time taken by Jasper Server was comparatively very less than time taken by Jasper server library, report of 2 years data, when 2 requests were hit simutaneously (it's huge data) took aroound 9.55 mins for Jasper Library and for Jasper server same took 5/6 mins.

So what change do I need to do in report generated using Jasper Library?

Thanks n regards,

Archana