This led to an exception when I run it concurrently (by using about 100 threads). AbderaClient uses HTTPClient and MultiThreadedHttpConnectionManager. Teardown method is the one who shuts down this connection manager and the best practice is to call teardown after using AbderaClient instance.
AbderaClient abderaClient = new AbderaClient(new Abdera()); // make the call abderaClient.teardown();
Sharing a single instance of AbderaClient among all request is another option but some times it goes to a deadlock state (keeping a connection open for a long time is not recommended anyway).