I suspect there is a concurrency issue with the DefaultJSONWriter implementation. I have overridden the JSONInterceptor so a new instance of JSONUtil is used with every request and the issue is not happening anymore. I suppose there is a performance cost with that change but for now it works.
https://github.com/lalo-mx/struts/commit/ed29e3f4ed841ef13559c02da1c8dca9b68fb0a7 Does it sound reasonable what I have found? Or should I better review the configuration / documentation for some other change that I have not contemplated? On 2019/01/25 23:57:44, Eduardo Quintanilla <[email protected]> wrote: > Hi, > > I recently upgraded Struts from version 2.3.34 to 2.5.20. After doing the recommended fixes the application runs correctly but an exception started happening sporadically. > > The app is built and runs in JDK 8 with Tomcat 9.0.12 > > The app is a little big so i have not able to create an example yet. > The more relevant libraries in use are Spring + Struts + Hibernate > > Any tips about how to find the root cause of the issue? > > > Request: > Request URL: https://localhost/app/rest/custom.action > Request Payload: {"params":["example"],"method":"load","id":1} > > Logs: > DefaultDispatcherErrorHandler: Exception occurred during processing request: null > java.util.EmptyStackException: null > at java.util.Stack.peek(Stack.java:102) ~[?:1.8.0_191] > at java.util.Stack.pop(Stack.java:84) ~[?:1.8.0_191] > at org.apache.struts2.json.DefaultJSONWriter.process(DefaultJSONWriter.java:196) ~[struts2-json-plugin-2.5.20.jar:2.5.20] > at org.apache.struts2.json.DefaultJSONWriter.value(DefaultJSONWriter.java:154) ~[struts2-json-plugin-2.5.20.jar:2.5.20] > at org.apache.struts2.json.DefaultJSONWriter.write(DefaultJSONWriter.java:121) ~[struts2-json-plugin-2.5.20.jar:2.5.20] > at org.apache.struts2.json.JSONUtil.serialize(JSONUtil.java:140) ~[struts2-json-plugin-2.5.20.jar:2.5.20] > at org.apache.struts2.json.JSONUtil.serialize(JSONUtil.java:110) ~[struts2-json-plugin-2.5.20.jar:2.5.20] > at org.apache.struts2.json.JSONInterceptor.intercept(JSONInterceptor.java:178) ~[struts2-json-plugin-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:250) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:179) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.doIntercept(ConversionErrorInterceptor.java:142) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:137) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:137) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:201) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:133) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:101) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:142) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:160) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:175) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at org.apache.struts2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:121) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:167) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:203) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:196) ~[struts2-core-2.5.20.jar:2.5.20] > at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) ~[struts2-core-2.5.20.jar:2.5.20] > at org.apache.struts2.factory.StrutsActionProxy.execute(StrutsActionProxy.java:48) ~[struts2-core-2.5.20.jar:2.5.20] > at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:574) [struts2-core-2.5.20.jar:2.5.20] > at org.apache.struts2.dispatcher.ExecuteOperations.executeAction(ExecuteOperations.java:79) [struts2-core-2.5.20.jar:2.5.20]
