Speed of third-party jars for report generation

Using JasperReports on Lucee 4.5 was fast and is significantly slower on Lucee 5.

The generation of the input data for the reports is done in a second, on Lucee 4.5 and 5, but the report rendering lasts about 30 to 90 seconds in Lucee 5. On Lucee 4.5 the rendering is done in in less than 10 seconds. I’ve updated to the newest JasperReports jars, upgraded from Java 7 to 8. Just the same.

System data: Lucee, 64bit Linux, Apache Tomcat/8.5.14, Java 1.8.0_131, System RAM 8GB, Tomcat/Java memory: 6 GB

The JasperReports jars are copied to the Lucee lib directory. Is there a way to speed up the execution of third-party jars?

Because of a customer complaint that he had to wait up to 4 minutes for a report I switched on the live server back to Lucee 4.5. Same version of Apache Tomcat, Java 1.8, RAM and the same JasperReports jars. The reports are now generated between 3 to 10 seconds.