About Password Expiration in Oracle Database 11g

In the Apex Installation Guide you will find the following paragraph:

"In the default profile in Oracle Database 11g, the parameter PASSWORD_LIFE_TIME is set to 180. If you are using Oracle Database 11g with Oracle Application Express, this causes the password for APEX_PUBLIC_USER to expire in 180 days. As a result, your Oracle
Application Express instance will become unusable until you change the password.

To prevent this behavior, create another profile in which the PASSWORD_LIFE_TIME parameter is set to unlimited and alter the APEX_PUBLIC_USER account and assign it to the new profile."

Of course with a little help from google you can find out how to do this. I summarized it for you:

First let's see what the limits of the default profile (or the profile of your APEX_PUBLIC_USER) are:

select resource_name

      ,limit

  from dba_profiles

 where profile = 'DEFAULT';

It will result in something like this:

RESOURCE_NAME                    LIMIT

-------------------------------- -------------------------------------

COMPOSITE_LIMIT                  UNLIMITED

SESSIONS_PER_USER                UNLIMITED

CPU_PER_SESSION                  UNLIMITED

CPU_PER_CALL                     UNLIMITED

LOGICAL_READS_PER_SESSION        UNLIMITED

LOGICAL_READS_PER_CALL           UNLIMITED

IDLE_TIME                        UNLIMITED

CONNECT_TIME                     UNLIMITED

PRIVATE_SGA                      UNLIMITED

FAILED_LOGIN_ATTEMPTS            10

PASSWORD_LIFE_TIME               180

PASSWORD_REUSE_TIME              UNLIMITED

PASSWORD_REUSE_MAX               UNLIMITED

PASSWORD_VERIFY_FUNCTION         NULL

PASSWORD_LOCK_TIME               1

PASSWORD_GRACE_TIME              7

There are two options. First you can change the default profile, but the profile of the other users will change accordingly and that may be a security vulnerability. But this is how you do it: 

alter profile default limit

   password_life_time unlimited;

Second, and my favorite, add a new profile and link it to the APEX_PUBLIC_USER user: 

create profile apex_public limit

   password_life_time unlimited;

alter user apex_public_user

   profile apex_public;

The first query will create a new profile with all limits to default except the password_life_time. The second one changes the profile of the APEX_PUBLIC_USER. 

And... don't forget to change the profile for your APEX_LISTENER and APEX_REST_PUBLIC_USER.