由于12c弃用了SQLNET.ALLOWED_LOGON_VERSION参数。
使用如下参数替代：
SQLNET.ALLOWED_LOGON_VERSION_SERVER = n
SQLNET.ALLOWED_LOGON_VERSION_CLIENT = n

官方说明：

12c Database Alert.log File Shows The Message: Using Deprecated SQLNET.ALLOWED_LOGON_VERSION Parameter (文档 ID 2111876.1)

解决方法：

In order to suppress these messages in the alert log of the database, you need to use the new parameters for the 12c database.

 STEPS:

 1. Edit the sqlnet.ora file of the 12c database. (This needs be done on each database on 12c). So for example if both your EBS and CCG databases are on 12c, you need to do this on each sqlnet.ora file. Typically, the sqlnet.ora file that would be referenced by the database is located in RDBMS_HOME/network/admin

 2. Remove or comment the following entry.

    SQLNET.ALLOWED_LOGON_VERSION

 3.You need to follow the instructions below:

 3a. Add the following two new Oracle Net Services parameters:

    SQLNET.ALLOWED_LOGON_VERSION_SERVER = n
    SQLNET.ALLOWED_LOGON_VERSION_CLIENT = n

    Specify the value for 'n' based on your own environment. The default setting for the new parameters is 11. Any client that attempts to connect must be at version 11 or higher unless these   parameters are explicitly set in the server side sqlnet.ora file.       

   3b. For example: Set these parameters at the lowest version level that is required in your environment.
        The example shpow below shows the following: All clients at version 10 or higher would require this setting:

       SQLNET.ALLOWED_LOGON_VERSION_SERVER=10
       SQLNET.ALLOWED_LOGON_VERSION_CLIENT=10

    3c. Note that SQLNET.ALLOWED_LOGON_VERSION_CLIENT would be necessary on the server when the database is 'acting' as a client. Such as the case of a database link as in the case of CCG applications.

    3d. Even though the parameter value implies Oracle version 10 the internal check is really against the authentication protocol 'SHA-1'

    3e. For CCG, you can just set the parameter value to 10, since SHA-2 is currently not certified with CCG.

    3e. See the following reference for more information about these settings.
         https://docs.oracle.com/database/121/NETRF/sqlnet.htm#NETRF2010

4. For setting up the values for step 3, you can also refer to the additional info section at the end of the note.

4. Bounce the database.

5. Bounce the application server.

报错日志:

Tue Nov 13 19:17:06 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:06 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:07 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:12 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:17 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:17 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:17 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:21 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:21 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:21 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:22 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:22 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:26 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:27 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:27 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:27 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:27 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Tue Nov 13 19:17:32 2018
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.
Using deprecated SQLNET.ALLOWED_LOGON_VERSION parameter.