code: public void initialize()
              throws SmackException.NotLoggedInException, CorruptedOmemoKeyException, InterruptedException,
              SmackException.NoResponseException, SmackException.NotConnectedException, XMPPException.XMPPErrorException,
              PubSubException.NotALeafNodeException {
          synchronized (LOCK) {
              if (!connection().isAuthenticated()) {
                  throw new SmackException.NotLoggedInException();
              }
  
              if (getTrustCallback() == null) {
                  throw new IllegalStateException("No TrustCallback set.");
              }
  
              getOmemoService().init(new LoggedInOmemoManager(this));
              ServiceDiscoveryManager.getInstanceFor(connection()).addFeature(PEP_NODE_DEVICE_LIST_NOTIFY);
          }
      }
docs: Initializes the OmemoManager. This method must be called before the manager can be used.
  
  @throws CorruptedOmemoKeyException
  @throws InterruptedException
  @throws SmackException.NoResponseException
  @throws SmackException.NotConnectedException
  @throws XMPPException.XMPPErrorException
  @throws SmackException.NotLoggedInException
  @throws PubSubException.NotALeafNodeException