question: public void start ( ) { if ( sLogger . isActivated ( ) ) { sLogger . info ( "Start address book monitoring" ) ; } mCleanupExecutor = Executors . newSingleThreadExecutor ( ) ; if ( ! mObserverIsRegistered ) { mContactsContractObserver = new ContactsContractObserver ( new Handler ( ) ) ; mContactsContractCursor = mContentResolver . query ( Phone . CONTENT_URI , null , null , null , null ) ; CursorUtil . assertCursorIsNotNull ( mContactsContractCursor , Phone . CONTENT_URI ) ; mContactsContractCursor . registerContentObserver ( mContactsContractObserver ) ; mObserverIsRegistered = true ; } }
target:  Start address book monitoring