title: Cannot connect Oracle database by Sqldeveloper(ORA-01017，invalid username/password;logon denied)
body: <p>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)：</p>
  
  <p><a href="https://i.imgur.com/qYLlzyf.png" rel="nofollow noreferrer"><img src="https://i.imgur.com/qYLlzyf.png" alt=""></a></p>
  
  <p>But I got：</p>
  
  <blockquote>
    <p>ORA-01017，invalid username/password;logon denied</p>
  </blockquote>
  
  <p>the tnsnames.ora is：</p>
  
  <pre><code>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)
  )
  )
  </code></pre>
  
  <p>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。</p>
  
  <p>So I tried to login sqlplus，trying to know account and password；I entered some accounts like sys、system、sysdba：</p>
  
  <p><a href="https://i.imgur.com/0j5uHlP.png" rel="nofollow noreferrer"><img src="https://i.imgur.com/0j5uHlP.png" alt=""></a></p>
  
  <p>it was still </p>
  
  <blockquote>
    <p>ORA-01017，invalid username/password;logon denied</p>
  </blockquote>
  
  <p>the account and password I entered were：</p>
  
  <pre><code>account  password
  sys      change_on_install
  system   manager
  sysman   oem_temp
  </code></pre>
  
  <p>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。</p>
  
  <p>How could I do for the exception?</p>