As you can see i tryied different ways to get the app context but if i launch my action Alfresco gaves me: <javascript>Failed to run Actions due to error: Error creating bean with name 'checkOutCheckInServiceHandler' defined in file [/opt/alfresco-4.2.c/tomcat/webapps/alfresco/WEB-INF/classes/alfresco/module/org.alfresco.module.vti/context/vti-handler-context.xml]: Cannot resolve reference to bean 'webDAVLockService' while setting bean property 'webDAVLockService'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'webDAVLockService' is defined</javascript>
where is my fault? those beans and that context file sounds strange…
please don't try to get the application context in that manner within an Action. There is absolutely no need to - you can inject all the services you require by providing a field, a setter and the necessary "<property>" definition in the Spring context file. Have a look at <a href="http://wiki.alfresco.com/wiki/Custom_Actions#Configuring_in_Spring">the Custom Actions wiki page</a>. The problem you are having should solve itself this way - the problem is, that you are essentially trying to start a new Alfresco Repository within an already running instance.
..well..while i was re-reading the action page wiki i noticed that i didn't update the custom action and so i noticed the same thing you said , anyway thanks!