@Override
    protected void beforeDelete(ModeledAuthenticatedUser user, String identifier) throws GuacamoleException {

        super.beforeDelete(user, identifier);

        // Do not allow users to delete themselves
        if (identifier.equals(user.getUser().getIdentifier()))
            throw new GuacamoleUnsupportedException("Deleting your own user is not allowed.");

    }
The server environment for retrieving configuration.
extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/user/UserService.java