2017-03-17 23:21 GMT+03:00 Mike Wilson <mike...@hotmail.com>: > > I also ran into [1]. > > Some Tomcat configuration with custom components (Valves, Managers etc) may > be done from a webapp's META-INF/context.xml. But currently if those classes > are your own custom implementations they will not be found if residing > inside the webapp's war (but are f ex found if placed in <tomcat>/lib). > > Would it make sense for Tomcat to use the webapp classloader for components > that are specified in META-INF/context.xml? > > Best regards > Mike Wilson > > [1] > http://stackoverflow.com/questions/10924715/creating-a-custom-tomcat-session > -manager-without-putting-the-jar-in-the-catalina >
Besides the security issues that Mark mentions, Note that Web application's classloader is only available when the web application is running. It means that 1) All those custom classes (Listeners, Valves etc.) cannot be created at the time when context.xml is parsed, and must be replaced with some stub objects. 2) They cannot process "destroy" event (when the application is undeployed), as the classloader is stopped earlier - on "stop" event. http://tomcat.apache.org/tomcat-8.5-doc/api/org/apache/catalina/Lifecycle.html 3) As Webapp classloader has priority over Tomcat classloader, you cannot really create any component before Webapp classloader is started - as the same class can be redefined in the web application. http://tomcat.apache.org/tomcat-8.5-doc/class-loader-howto.html 4) Some objects are needed before Webapp classloader is started. If context.xml redefines / reconfigures classloader implementation (Loader element) - when is it created, and how? What classloader is used to load and create it and why? http://tomcat.apache.org/tomcat-8.5-doc/config/loader.html A Listener can reconfigure web application before it is started. Some of those will be broken. E.g. a listener can perform the same actions as "PreResources" or "PostResources" elements to inject additional JARs into webapp classpath. It is better to do that before starting a web application class loader. http://tomcat.apache.org/tomcat-8.5-doc/config/resources.html 5) Configuration of a web application can be performed externally, via JMX API. What objects will be exposed via JMX and starting with what moment / state? http://tomcat.apache.org/tomcat-8.5-doc/monitoring.html Best regards, Konstantin Kolinko --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
