Cannot connect Oracle database by Sqldeveloper(ORA-01017，invalid username/password;logon denied)

Question

I just install Oracle 12c datadase in my computer，the process of installing is normal，having no any problem。After finnishing the installing，I tried to estalish a new connection(the IP is localhost:1521，service_name is orcl)：

But I got：

ORA-01017，invalid username/password;logon denied

the tnsnames.ora is：

LISTENER_ORCL =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))

ORCL =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = orcl)
)
)

What's up? tnsnames.ora just showed the IP is localhost，post is 1521，and service_name is orcl，but I cannot still connect db。

So I tried to login sqlplus，trying to know account and password；I entered some accounts like sys、system、sysdba：

it was still

ORA-01017，invalid username/password;logon denied

the account and password I entered were：

account  password
sys      change_on_install
system   manager
sysman   oem_temp

I had entered these accounts and passwords，and I just got the same exception，so the exception may not happen because of the wrong accounts or passwords。

How could I do for the exception?

Answer 1

During the installation process, you were asked to provide passwords for SYS and SYSTEM. Doing so, you should have written them somewhere so that you wouldn't forget them.

Now, log on to the computer as user who owns Oracle software and - at the operating system command prompt - run

sqlplus / as sysdba

That should let you in. Then, use

alter user any_username identified by its_password;

to change passwords (but this time try to remember them).

Answer 2

The question about a password?change_on_install??

does not mean ?change_on_install??Which means the string when you install Oracle DB you enter?

Such as?https://i.imgur.com/zShGv4A.png

(noticing the string was blocked by a red border?)

So I just enter the string which is blocked by the red line on the above picture when I tried to login the ?system? account?

And then I could login the ?system? account?

When I login the account?I could add a new user account?so my question was solved??

Answer 3

ORA-01017: It depends on what is creating this error message. For me simply changing the parameter SQLNET.AUTHENTICATION_SERVICES from None to NTS in SQLNET.ora file solved the issue.