OK. Done. I had to update also the JDK to 1.8.0, which brought some other issues, but now it works.
It is faster than the previous, but not yet as fast as the iOS version.
I still get some of these logs:
01:12 W/SQLiteConnectionPool: The connection pool for database '+data+data+com_diveplanapp_beta+files+diveplan_cblite' has been unable to grant a connection to thread 1153 (CBLRequestWorker-e93ca-0) with flags 0x2 for 16.001001 seconds.
That I think are contributing to the delay. The time mentioned in the logs is anyway lower than before.
Waiting for the new version to see if it improves further.
Thanks!
Luca