MongoDB difference between error code 11000 and 11001

Question

According to this HIGHLY incomplete list http://www.mongodb.org/about/contributors/error-codes/ they\'re both related to duplicate keys. But I was not able to get a

Answer 1

Mongo has an ErrorCategory enum which creates a DUPLICATE_KEY_ERROR for the following error codes:

private static final List DUPLICATE_KEY_ERROR_CODES = Arrays.asList(11000, 11001, 12582);

The above is from mongodb java driver 3.6.4.

So both refer to duplicate keys.