Openjdk openJ9 vs hotspot reflection difference using ZKOSS

I'm currently using a web application using the ZK (https://www.zkoss.org/) framework successfully using a HotSpot JVM (https://adoptopenjdk.net/?variant=openjdk11&jvmVariant=hotspot). Using this JVM, ZK can reflectively access my objects (beans) using its EL package. When I try running it with another standard-JVM (openj9 from https://adoptopenjdk.net/?variant=openjdk11&jvmVariant=openj9), reflectively accessing attributions of certain object lead to exceptions (see end of this message). I'd like to use this JVM as its memory footprint is smaller than hotspot for my application.

Is there any reason why a different JVM would lead to different results? If so, how should I troubleshoot it?

In this specific case, ZK uses a forked version of Apache Common EL, which is a discontinued project.(2003). The exception I get is listed below. Here, the framework has failed to access the object (application-level object, not java.lang.Long) in question, and is calling a method that does not exist on Long (but exists in application object).

org.zkoss.zel.PropertyNotFoundException: Property 'visible' not found on type java.lang.Long
at org.zkoss.zel.BeanELResolver$BeanProperties.get(BeanELResolver.java:424) ~[zel_8.6.2.jar:8.6.2]
at org.zkoss.zel.BeanELResolver$BeanProperties.access$300(BeanELResolver.java:375) ~[zel_8.6.2.jar:8.6.2]
at org.zkoss.zel.BeanELResolver.property(BeanELResolver.java:547) ~[zel_8.6.2.jar:8.6.2]
at org.zkoss.zel.BeanELResolver.getValue(BeanELResolver.java:98) ~[zel_8.6.2.jar:8.6.2]
at org.zkoss.zel.CompositeELResolver.getValue(CompositeELResolver.java:66) ~[zel_8.6.2.jar:8.6.2]
at org.zkoss.zel.CompositeELResolver.getValue(CompositeELResolver.java:66) ~[zel_8.6.2.jar:8.6.2]
at org.zkoss.zel.CompositeELResolver.getValue(CompositeELResolver.java:66) ~[zel_8.6.2.jar:8.6.2]
at org.zkoss.xel.zel.XelELResolver.getValue(XelELResolver.java:99) ~[zcommon_8.6.2.jar:8.6.2]
at org.zkoss.bind.xel.zel.BindELResolver.getValue(BindELResolver.java:123) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.zel.impl.parser.AstValue.getValue(AstValue.java:188) ~[zel_8.6.2.jar:8.6.2]
at org.zkoss.zel.impl.ValueExpressionImpl.getValue(ValueExpressionImpl.java:184) ~[zel_8.6.2.jar:8.6.2]
at org.zkoss.zkmax.bind.impl.ValueExpressionImplEx.getValue(ValueExpressionImplEx.java:52) ~[zkmax_8.6.2.jar:8.6.2]
at org.zkoss.xel.zel.ELXelExpression.evaluate(ELXelExpression.java:41) ~[zcommon_8.6.2.jar:8.6.2]
at org.zkoss.zkmax.bind.impl.BindEvaluatorXImplEx$LazyBindXelExpression.evaluate(BindEvaluatorXImplEx.java:124) ~[zkmax_8.6.2.jar:8.6.2]
at org.zkoss.bind.impl.BindEvaluatorXImpl.getValue(BindEvaluatorXImpl.java:46) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.impl.LoadPropertyBindingImpl.load(LoadPropertyBindingImpl.java:58) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.impl.PropertyBindingHandler.doLoadBinding(PropertyBindingHandler.java:140) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.impl.PropertyBindingHandler.doLoad(PropertyBindingHandler.java:341) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.impl.BinderImpl.loadComponentProperties0(BinderImpl.java:2491) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.impl.BinderImpl.loadComponent0(BinderImpl.java:2458) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.impl.BinderImpl.loadComponent(BinderImpl.java:2393) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.tracker.impl.BindUiLifeCycle.reInitBinder0(BindUiLifeCycle.java:170) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.tracker.impl.BindUiLifeCycle.reInitBinder(BindUiLifeCycle.java:109) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.tracker.impl.BindUiLifeCycle.access$100(BindUiLifeCycle.java:55) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.bind.tracker.impl.BindUiLifeCycle$2.onEvent(BindUiLifeCycle.java:100) ~[zkbind_8.6.2.jar:8.6.2]
at org.zkoss.zk.ui.AbstractComponent.onEvent(AbstractComponent.java:3179) ~[zk_8.6.2.jar:8.6.2]
at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:3127) ~[zk_8.6.2.jar:8.6.2]
at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:3091) ~[zk_8.6.2.jar:8.6.2]
at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:138) ~[zk_8.6.2.jar:8.6.2]
at org.zkoss.zk.ui.impl.UiEngineImpl.processEvent(UiEngineImpl.java:1845) ~[zk_8.6.2.jar:8.6.2]
at org.zkoss.zk.ui.impl.UiEngineImpl.process(UiEngineImpl.java:1617) ~[zk_8.6.2.jar:8.6.2]
at org.zkoss.zk.ui.impl.UiEngineImpl.execUpdate(UiEngineImpl.java:1320) ~[zk_8.6.2.jar:8.6.2]
at org.zkoss.zk.au.http.DHtmlUpdateServlet.process(DHtmlUpdateServlet.java:611) ~[zk_8.6.2.jar:8.6.2]
at com.castortech.iris.ba.webviewer.internal.ZkUpdateServlet.process(ZkUpdateServlet.java:62) ~[com.castortech.iris.ba.webviewer/:na]
at org.zkoss.zk.au.http.DHtmlUpdateServlet.doGet(DHtmlUpdateServlet.java:487) ~[zk_8.6.2.jar:8.6.2]
at org.zkoss.zk.au.http.DHtmlUpdateServlet.doPost(DHtmlUpdateServlet.java:495) ~[zk_8.6.2.jar:8.6.2]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) ~[javax.servlet_3.1.0.v201410161800.jar:3.1.0]