Hello, I have Jasperreports server on Tomcat (REST v2 web service) and when I generate report for approx. 500 records, server get stuck. Reason of this is heap overflow (I attach plot obtained by Visual VM). After using Eclipse Memory Analyzer, I have two problems suspect: One instance of "org.apache.catalina.session.StandardManager" loaded by "java.net.URLClassLoader @ 0xb720c558" occupies 953 430 520 (74,78%) bytes. The memory is accumulated in one instance of "java.util.concurrent.ConcurrentHashMap$Node[]" loaded by "<system class loader>". 1143 instances of "net.sf.jasperreports.renderers.SimpleDataRenderer", loaded by "org.apache.catalina.loader.WebappClassLoader @ 0xb79a3710" occupy 135 271 064 (10,61%) bytes. These instances are referenced from one instance of "java.util.concurrent.ConcurrentHashMap$Node[]", loaded by "<system class loader>" Where the first one is much more serious (it occupy 7 times more heap). Do you have any ideas how to solve it?