code: public void chtype(String resourcename, I_CmsResourceType type) throws CmsException {
  
          CmsResource resource = readResource(resourcename, CmsResourceFilter.IGNORE_EXPIRATION);
          getResourceType(resource).chtype(this, m_securityManager, resource, type);
      }
docs: Changes the resource type of a resource.<p>
  
  OpenCms handles resources according to the resource type,
  not the file suffix. This is e.g. why a JSP in OpenCms can have the
  suffix ".html" instead of ".jsp" only. Changing the resource type
  makes sense e.g. if you want to make a plain text file a JSP resource,
  or a binary file an image, etc.<p>
  
  @param resourcename the name of the resource to change the type for (full current site relative path)
  @param type the new resource type for this resource
  
  @throws CmsException if something goes wrong