In the maven project, I add dependency modeshape-web-explorer.jar, which runs as a war package under tomcat.

     modeshape-web-explorer doesn't work in web-explorer.

     I debugged Tomcat remotely under eclipse and found:

          org.modeshape.web.server.impl.LRepositoryImpl class：

public LRepositoryImpl( ServletContext context, JcrRepository repository,

                            Credentials creds ) throws LoginException, RepositoryException {

        this.context = context;

        this.creds = creds;

        assert repository != null;

        this.repository = repository;

        logger.debug("Logging to repository " + repository + " as " + creds);

        Session session = creds != null ? repository.login(creds) : repository.login();

        sessions.put(session.getWorkspace().getName(), session);

        workspaces = session.getWorkspace().getAccessibleWorkspaceNames();

        logger.debug("[" + this.repository.getName() + "] available workspaces " + wsnames());

        tempDir = (File) context.getAttribute("javax.servlet.context.tempdir");

    }

ServletContext is  null,so Null pointer exception：

  logger.debug("Could not start repository " + name, e);

                throw new RemoteException(e.getMessage());