Define the "Minimum Number of Non-Alphabetic Characters" appropriately.
(1) number of characters
(1) via the Administration Console, Security Realm > Name of the active Realm > Providers > Password Validation > System Password Validator > Provider Specific > Minimum Number of Non-Alphabetic Characters field
link down to section 5.8.1 Table 5-7, "Password Composition Rules and Default Values" scroll to p70
Oracle Fusion Middleware: Securing Oracle WebLogic Server, 11g Release 1 (10.3.1)
Oracle
2009-05-01
10.3.1
Prose(pdf)