Error uplifting OGNL from 3.3.4 to 3.4.2 with struts2(6.3.0.2)

Question

My application is based on struts2 (v 6.3.0.2) and I am currently using ognl v3.3.4 as one of its dependency. The application is working fine with these version.

When I try to uplift the OGNL to latest version i.e 3.4.2 I am getting the below error:

                at com.opensymphony.xwork2.ognl.OgnlValueStack.setRoot(OgnlValueStack.java:102)
                at com.opensymphony.xwork2.ognl.OgnlValueStack.<init>(OgnlValueStack.java:81)
                at com.opensymphony.xwork2.ognl.OgnlValueStackFactory.createValueStack(OgnlValueStackFactory.java:62)
                at com.opensymphony.xwork2.config.impl.DefaultConfiguration.setContext(DefaultConfiguration.java:244)
                at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:208)
                at com.opensymphony.xwork2.config.ConfigurationManager.reload(ConfigurationManager.java:227)
                at com.opensymphony.xwork2.config.ConfigurationManager.initialiseConfiguration(ConfigurationManager.java:84)
                at com.opensymphony.xwork2.config.ConfigurationManager.wasConfigInitialised(ConfigurationManager.java:72)
                at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:61)
                at org.apache.struts2.dispatcher.Dispatcher.getContainer(Dispatcher.java:1079)
                at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:537)
                at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:571)
                at org.apache.struts2.dispatcher.InitOperations.initDispatcher(InitOperations.java:48)
                at org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:60)
                at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:262)
                at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:244)
                at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:97)
                at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4311)
                at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:4940)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:683)
                at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:658)
                at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:661)
                at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1014)
                at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1866)
                at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
                at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
                at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
                at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:118)
                at org.apache.catalina.startup.HostConfig.deployWARs(HostConfig.java:816)
                at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:468)
                at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1584)
                at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:312)
                at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:114)
                at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:402)
                at org.apache.catalina.util.LifecycleBase.setState(LifecycleBase.java:345)
                at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:893)
                at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:794)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1332)
                at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1322)
                at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
                at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
                at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:140)
                at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:866)
                at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:248)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.core.StandardService.startInternal(StandardService.java:433)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:925)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.startup.Catalina.start(Catalina.java:735)
                at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
                at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
                at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.base/java.lang.reflect.Method.invoke(Method.java:566)
                at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:345)
                at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:476)

from what I have found out is that ognl.OgnlValueStack.setRoot calls ognl.Ognl.createDefaultContext. In 3.3.4 createDefaultContext return type was Map. In 3.4.2 createDefaultContext return type is OgnlContext. This incompatibility is the cause of error, but is there any solution to that from my code perspective? or its simply OGNL (3.4.2) is not compatible with struts2 (6.3.0.2).

Answer 1

The OgnlContext ia a Map<String, Object>. In Struts 2 OgnlContext is set to ActionContext and ValueStack is a root object in it. For more information read:

• OGNL

The framework sets the OGNL context to be our ActionContext, and the ValueStack to be the OGNL root object. (The ValueStack is a set of several objects, but to OGNL it appears to be a single object). Along with the value stack, the framework places other objects in the ActionContext, including maps representing the application, session, and request contexts. These objects coexist in the ActionContext, alongside the value stack (our OGNL root).

The ActionContext is not a Map<String, Object>, but you can get a context map with

OgnlContext context = (OgnlContext) ActionContext.getContext().getContextMap();

The ValuStack has there own context. There's also a Map<String, Object> you can get

OgnlContext context = (OgnlContext) ActionContext.getContext().getValueStack().getContext();

Which version you use depends on implementation. You cannot just uplift a version of the API and use it with artifacts that require a lower version.