This section details the usage of Smacks implementation of Entity Capabilities.

Entity Capabilities is a XMPP Protocol extension, which, in order to minimize network impact, caches the capabilities of XMPP entities. Those capabilities are determined with the help of the Service Discovery Protocol (XEP-0030).

Entity Capabilities work silenty in background when enabled. If the remote XMPP entity does not support XEP-0115 but XEP-0030 then XEP-0030 mechanisms are transparently used. You can enable or disable Entity Capabilities by using EntityCapsManager.
The cache used by Smack for Entity Capabilities is non-persistent as default. That is, the cache only uses memory. But it is also possible to set a persistent Entity Capabilities cache, which is recommended.

Enable Entity Capabilities

      // Get an instance of entity caps manager for the specified connection
      Entity CapabilitiesManager mgr = new EntityCapsManager.getInstanceFor(con);

      // Enable entity capabilities
      mgr.enableEntityCaps();

      // Get an instance of entity caps manager for the specified connection
      Entity CapabilitiesManager mgr = new EntityCapsManager.getInstanceFor(con);

      // Create an cache, see smackx.entitycaps.cache for pre-defined cache implementations
      EntityCapsPersistentCache cache = new SimpleDirectoryPersistentCache(new File("/foo/cachedir"));

      // Set the cache
      mgr.setPersistentCache(cache);