I'm working on Struts 2 migration. My Struts 1 application is using ModuleConfig and PlugInConfig classes. How to use these classes in Struts 2?
ModuleConfig and PlugInConfig are Struts1 classes. Struts2 framework is different in architecture and uses it's own classes used to parse and build the configuration. So, if your application used those classes and you unable to remove them at the moment you should consider the option to run both frameworks together. Also, if you decide to remove them after rewriting the configuration, but want to reuse actions and forms in Struts2 consider struts2-struts1-plugin and struts1-solutions. This allows to use existing actions and forms in the Struts2 framework, but this is more complicated in Struts2 rather than writing a Struts2 only web application from scratch.