the difference between Activity.managedQuery and ContentResolver.query

final Cursor managedQuery(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)

This method was deprecated in API level 11. Use CursorLoader instead. 

final Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)

Query the given URI, returning a Cursor over the result set.

managedQuery() will use ContentResolver's query(). The difference is that with managedQuery() the activity will keep a reference to your Cursor and close it whenever needed (in onDestroy() for instance.) If you do query() yourself, you will have to manage the Cursor as a sensitive resource. If you forget, for instance, to close() it in onDestroy(), you will leak underlying resources (logcat will warn you about it.) 

To query a content provider, you can use either the ContentResolver.query() method or the Activity.managedQuery() method. Both methods take the same set of arguments, and both return a Cursor object. However, managedQuery() causes the activity to manage the life cycle of the Cursor. A managed Cursor handles all of the niceties, such as unloading itself when the activity pauses, and requerying itself when the activity restarts. You can ask an Activity to begin managing an unmanaged Cursor object for you by calling Activity.startManagingCursor().