[#5506] - Out of memory after lots of reports

wrote a java code to download (store in local files) multiple pdf reports from my instance of JasperReport Server. It works well for about 600 reports, after that it produce an error 500. In the JasperServer log file I see an Out of memory exception.

Tested on jasperserver 5.6 and on jasperserver 6.1

here you can see my java code (class ga.system.jasperserver.ReportExtractor)

for (ReportParameters aReportParams : listOfReportParameters)
{
String filename = "report-"+aReportParams.getParameter1()+ ".PDF";
jasperreport_url = combineParamsIntoJasperserverUrl(aReportParams);
URL website = new URL(jasperreport_url);
ReadableByteChannel rbc = Channels.newChannel(website.openStream());
FileOutputStream fos = new FileOutputStream(destPath+"/" +filename);
fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
fos.close();
rbc.close();
}

here you can see a snippet of the exception I get

java.io.IOException: Server returned HTTP response code: 500 for URL: http://myjasperserverurl/jasperserver/rest_v2/reports/TestDir/TestReport... at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) at java.net.URL.openStream(Unknown Source) at ga.system.jasperserver.ReportExtractor.extract(ReportExtractor.java:102) ... ... ...

Here you can see the log in JasperReport Server version 5.6 (catalina.out snippet)

2015-08-17 18:16:17,091 ERROR RunReportServiceImpl,pool-5-thread-66:511 - caught Throwable exception: Java heap space
java.lang.OutOfMemoryError: Java heap space
at java.util.Arrays.copyOf(Arrays.java:2271)
at java.io.ByteArrayOutputStream.grow(ByteArrayOutputStream.java:113)
at java.io.ByteArrayOutputStream.ensureCapacity(ByteArrayOutputStream.java:93)
at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:140)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
at com.lowagie.text.pdf.OutputStreamCounter.flush(Unknown Source)
at com.lowagie.text.DocWriter.close(Unknown Source)
at com.lowagie.text.pdf.PdfWriter.close(Unknown Source)
at com.lowagie.text.pdf.PdfDocument.close(Unknown Source)
at com.lowagie.text.Document.close(Unknown Source)
at net.sf.jasperreports.engine.export.JRPdfExporter.exportReportToStream(JRPdfExporter.java:815)
at net.sf.jasperreports.engine.export.JRPdfExporter.exportReport(JRPdfExporter.java:513)
at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl.exportToPdf(EngineServiceImpl.java:559)
at com.jaspersoft.jasperserver.remote.exporters.PdfExporter.exportReport(PdfExporter.java:98)
at com.jaspersoft.jasperserver.remote.services.impl.ReportExecutorImpl.exportReport(ReportExecutorImpl.java:177)
at com.jaspersoft.jasperserver.remote.services.impl.RunReportServiceImpl.generateReportOutput(RunReportServiceImpl.java:478)
at com.jaspersoft.jasperserver.remote.services.impl.RunReportServiceImpl.executeExport(RunReportServiceImpl.java:378)
at com.jaspersoft.jasperserver.remote.services.impl.RunReportServiceImpl$2.run(RunReportServiceImpl.java:343)
at com.jaspersoft.jasperserver.api.logging.util.LoggableExecutorService$1.run(LoggableExecutorService.java:59)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)

Virtualizer used in my server (applicationContext.xml snippet)

<bean id="fileVirtualizerFactory" class="com.jaspersoft.jasperserver.api.engine.common.service.impl.FileVirtualizerFactory">
<property name="maxSize" value="3000"></property>
<property name="directory" value="${java.io.tmpdir}"></property>
</bean>

I'm using JasperReport server 5.6.0 on Ubuntu 14.04 (trusty), java 8

EDIT 29/08/2015 new test using JasperReport server 6.1 on Ubuntu 14.04, java 8 Same result, freshly installed server, after 580 pdf produced the server hangs showing this message (read last line: "Caused by: java.lang.OutOfMemoryError: Java heap space"):

org.hibernate.exception.GenericJDBCException: could not initialize lazy properties: [com.jaspersoft.jasperserver.api.metadata.common.service.impl.hibernate.persistent.RepoFileResource#8448] at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126) at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.persister.entity.AbstractEntityPersister.initializeLazyPropertiesFromDatastore(AbstractEntityPersister.java:831) at org.hibernate.persister.entity.AbstractEntityPersister.initializeLazyProperty(AbstractEntityPersister.java:771) at org.hibernate.intercept.AbstractFieldInterceptor.intercept(AbstractFieldInterceptor.java:97) at org.hibernate.intercept.cglib.FieldInterceptorImpl.readObject(FieldInterceptorImpl.java:98) at com.jaspersoft.jasperserver.api.metadata.common.service.impl.hibernate.persistent.RepoFileResource.$cglib_read_data(Unknown Source) at com.jaspersoft.jasperserver.api.metadata.common.service.impl.hibernate.persistent.RepoFileResource.getData(Unknown Source) at com.jaspersoft.jasperserver.api.metadata.common.service.impl.hibernate.persistent.RepoFileResource.copyData(Unknown Source) at com.jaspersoft.jasperserver.api.metadata.common.service.impl.hibernate.HibernateRepositoryServiceImpl$22.execute(HibernateRepositoryServiceImpl.java:1420) at com.jaspersoft.jasperserver.api.metadata.common.service.impl.HibernateDaoImpl.executeCallback(HibernateDaoImpl.java:56) at com.jaspersoft.jasperserver.api.metadata.common.service.impl.hibernate.HibernateRepositoryServiceImpl.getResourceData(HibernateRepositoryServiceImpl.java:1414) at sun.reflect.GeneratedMethodAccessor337.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:319) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) at com.sun.proxy.$Proxy32.getResourceData(Unknown Source) at sun.reflect.GeneratedMethodAccessor337.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:319) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) at com.jaspersoft.jasperserver.api.metadata.user.service.impl.PermissionsPrefetcher.invoke(PermissionsPrefetcher.java:79) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at com.jaspersoft.jasperserver.api.metadata.user.service.impl.PermissionsPrefetcher.invoke(PermissionsPrefetcher.java:79) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.security.intercept.method.aopalliance.MethodSecurityInterceptor.invoke(MethodSecurityInterceptor.java:66) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.security.intercept.method.aopalliance.MethodSecurityInterceptor.invoke(MethodSecurityInterceptor.java:66) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) at com.sun.proxy.$Proxy38.getResourceData(Unknown Source) at com.jaspersoft.jasperserver.api.engine.jasperreports.util.repo.RepositoryConnection.getInputStream(RepositoryConnection.java:114) at java.net.URL.openStream(URL.java:1037) at net.sf.jasperreports.engine.util.JRLoader.getInputStream(JRLoader.java:298) at net.sf.jasperreports.repo.DefaultRepositoryService.getInputStream(DefaultRepositoryService.java:100) at net.sf.jasperreports.repo.InputStreamPersistenceService.load(InputStreamPersistenceService.java:48) at net.sf.jasperreports.repo.DefaultRepositoryService.getResource(DefaultRepositoryService.java:155) at net.sf.jasperreports.repo.RepositoryUtil.findInputStream(RepositoryUtil.java:176) at net.sf.jasperreports.repo.RepositoryUtil.getBytesFromLocation(RepositoryUtil.java:192) at net.sf.jasperreports.engine.RenderableUtil.getRenderable(RenderableUtil.java:121) at net.sf.jasperreports.engine.fill.JRFillImage.evaluateImage(JRFillImage.java:536) at net.sf.jasperreports.engine.fill.JRFillImage.evaluate(JRFillImage.java:472) at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:259) at net.sf.jasperreports.engine.fill.JRFillBand.evaluate(JRFillBand.java:456) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillBackground(JRVerticalFiller.java:1846) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportStart(JRVerticalFiller.java:288) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:152) at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:963) at net.sf.jasperreports.engine.fill.BaseFillHandle$ReportFiller.run(BaseFillHandle.java:120) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl$SynchronousExecutor.execute(EngineServiceImpl.java:886) at net.sf.jasperreports.engine.fill.BaseFillHandle.startFill(BaseFillHandle.java:165) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl.fillReport(EngineServiceImpl.java:1804) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl$SynchronousReportFiller.fillReport(EngineServiceImpl.java:790) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl.fillReport(EngineServiceImpl.java:1731) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl$ReportFill.runWithDataSource(EngineServiceImpl.java:1086) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl$ReportFill.runReport(EngineServiceImpl.java:1015) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl$ReportRunnable.run(EngineServiceImpl.java:908) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl$SynchronousExecutor.execute(EngineServiceImpl.java:886) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl.fillReport(EngineServiceImpl.java:607) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl.executeReportUnitRequest(EngineServiceImpl.java:1937) at com.jaspersoft.jasperserver.api.engine.jasperreports.domain.impl.ReportUnitRequest.execute(ReportUnitRequest.java:67) at com.jaspersoft.jasperserver.api.engine.jasperreports.service.impl.EngineServiceImpl.execute(EngineServiceImpl.java:497) at com.jaspersoft.jasperserver.remote.services.impl.ReportExecutorImpl$GenericRunReportStrategy.runReport(ReportExecutorImpl.java:225) at com.jaspersoft.jasperserver.remote.services.impl.ReportExecutorImpl.runReport(ReportExecutorImpl.java:127) at com.jaspersoft.jasperserver.remote.services.impl.RunReportServiceImpl$1.run(RunReportServiceImpl.java:230) at com.jaspersoft.jasperserver.api.logging.util.LoggableExecutorService$1.run(LoggableExecutorService.java:59) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:724) Caused by: org.postgresql.util.PSQLException: Fine memoria scaricando i risultati della query. at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1816) at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:255) at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:510) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:386) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:271) at org.apache.tomcat.dbcp.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96) at org.apache.tomcat.dbcp.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96) at org.hibernate.persister.entity.AbstractEntityPersister.initializeLazyPropertiesFromDatastore(AbstractEntityPersister.java:802) ... 73 more Caused by: java.lang.OutOfMemoryError: Java heap space

feel free to ask for details you need!
Please help
Thanks