Struts exception: caused by:parent package isn't defined:json-default-[unknown location] Workaround

Problem Description:

Unable to load configuration. -[Unknown Location]
At Com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration (configurationmanager.java:70)
At Org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration (dispatcher.java:445)
At Org.apache.struts2.dispatcher.Dispatcher.init (dispatcher.java:489)
At Org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher (initoperations.java:74)
At Org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init ( STRUTSPREPAREANDEXECUTEFILTER.JAVA:57)
At Org.apache.catalina.core.ApplicationFilterConfig.initFilter (applicationfilterconfig.java:279)
At Org.apache.catalina.core.ApplicationFilterConfig.getFilter (applicationfilterconfig.java:260)
At Org.apache.catalina.core.applicationfilterconfig.<init> (applicationfilterconfig.java:105)
At Org.apache.catalina.core.StandardContext.filterStart (standardcontext.java:4660)
At Org.apache.catalina.core.StandardContext.startInternal (standardcontext.java:5298)
At Org.apache.catalina.util.LifecycleBase.start (lifecyclebase.java:147)
At Org.apache.catalina.core.ContainerBase.addChildInternal (containerbase.java:725)
At Org.apache.catalina.core.ContainerBase.addChild (containerbase.java:701)
At Org.apache.catalina.core.StandardHost.addChild (standardhost.java:717)
At Org.apache.catalina.startup.HostConfig.deployDirectory (hostconfig.java:1092)
At Org.apache.catalina.startup.hostconfig$deploydirectory.run (hostconfig.java:1834)
At Java.util.concurrent.executors$runnableadapter.call (executors.java:511)
At Java.util.concurrent.FutureTask.run (futuretask.java:266)
At Java.util.concurrent.ThreadPoolExecutor.runWorker (threadpoolexecutor.java:1142)
At Java.util.concurrent.threadpoolexecutor$worker.run (threadpoolexecutor.java:617)
At Java.lang.Thread.run (thread.java:745)
caused by:parent package isn't defined:json-default-[unknown location]
At Com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.buildPackageContext ( xmlconfigurationprovider.java:670)
At Com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage (Xmlconfigurationprovider.java : 519)
At Com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages (Xmlconfigurationprovider.java : 292)
At Org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages (Strutsxmlconfigurationprovider.java : 112)
At Com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer (defaultconfiguration.java:258)
At Com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration (configurationmanager.java:67)
... More
December 17, 2016 9:33:15 pm Org.apache.catalina.core.StandardContext filterstart
Severity: Exception Starting filter Struts2
Unable to load configuration. -[Unknown Location]
At Org.apache.struts2.dispatcher.Dispatcher.init (dispatcher.java:501)
At Org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher (initoperations.java:74)
At Org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init ( STRUTSPREPAREANDEXECUTEFILTER.JAVA:57)
At Org.apache.catalina.core.ApplicationFilterConfig.initFilter (applicationfilterconfig.java:279)
At Org.apache.catalina.core.ApplicationFilterConfig.getFilter (applicationfilterconfig.java:260)
At Org.apache.catalina.core.applicationfilterconfig.<init> (applicationfilterconfig.java:105)
At Org.apache.catalina.core.StandardContext.filterStart (standardcontext.java:4660)
At Org.apache.catalina.core.StandardContext.startInternal (standardcontext.java:5298)
At Org.apache.catalina.util.LifecycleBase.start (lifecyclebase.java:147)
At Org.apache.catalina.core.ContainerBase.addChildInternal (containerbase.java:725)
At Org.apache.catalina.core.ContainerBase.addChild (containerbase.java:701)
At Org.apache.catalina.core.StandardHost.addChild (standardhost.java:717)
At Org.apache.catalina.startup.HostConfig.deployDirectory (hostconfig.java:1092)
At Org.apache.catalina.startup.hostconfig$deploydirectory.run (hostconfig.java:1834)
At Java.util.concurrent.executors$runnableadapter.call (executors.java:511)
At Java.util.concurrent.FutureTask.run (futuretask.java:266)
At Java.util.concurrent.ThreadPoolExecutor.runWorker (threadpoolexecutor.java:1142)
At Java.util.concurrent.threadpoolexecutor$worker.run (threadpoolexecutor.java:617)
At Java.lang.Thread.run (thread.java:745)
caused By:unable to load configuration. -[Unknown Location]
At Com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration (configurationmanager.java:70)
At Org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration (dispatcher.java:445)
At Org.apache.struts2.dispatcher.Dispatcher.init (dispatcher.java:489)
... More
caused by:parent package isn't defined:json-default-[unknown location]
At Com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.buildPackageContext ( xmlconfigurationprovider.java:670)
At Com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage (Xmlconfigurationprovider.java : 519)
At Com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages (Xmlconfigurationprovider.java : 292)
At Org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages (Strutsxmlconfigurationprovider.java : 112)
At Com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer (defaultconfiguration.java:258)
At Com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration (configurationmanager.java:67)
... More

Cause of Error:

Configuring the action when the contract is Json-default

<package name= "text" namespace= "/okk" extends= "Json-default" >

<action name= "imagesaction_*" class= "com.zj.practice.action.UpLoadImageAction" method= "{1}" >
<result name= "Images" type= "JSON" >list</result>
</action>

</package>

Workaround: Import the Struts2-json-plugin-2.3.16.3.jar package

Struts exception: caused by:parent package isn't defined:json-default-[unknown location] workaround