Suppose you have created a service user and mapped it to your bundle like in [1]. The code snippet should work for you. Session session =repository.loginAdministrative(repository.getDefaultWorkspace());UserManager uMgr = ((org.apache.jackrabbit.api.JackrabbitSession)session).getUserManager();..........

francesca​ You might have to reference using /etc.clientlibs but before that you need to configure "Client Library Folder and Using the Proxy Client Libraries Servlet" - Please check Using Client-Side Libraries - read section "Locating Client Library Folder and Using the Proxy Client Libraries Servl...