Java Oracle localhost connection error (ORA-12505)

Question

I am trying to currently connect to a database on my current computer.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class Main {
    public static void main(String[] argv) throws Exception {

        Connection connection = null;
        try {
            // Load the JDBC driver
            String driverName = "oracle.jdbc.driver.OracleDriver";
            Class.forName(driverName);

            // Create a connection to the database
            String serverName = "localhost";
            String portNumber = "1521";
            String sid = "xe";
            String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + ":" + sid;
            String username = "scott";
            String password = "tiger";
            connection = DriverManager.getConnection(url, username, password);
            System.out.println("Success");
        } catch (ClassNotFoundException e) {
            System.out.println("Class Not Found Error");
        } 
    }
}

I keep getting this error and I do not know why...

Exception in thread "main" java.sql.SQLException: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
The Connection descriptor used by the client was:
localhost:1521:xe

at oracle.jdbc.driver.SQLStateMapping.newSQLException(SQLStateMapping.java:70)
at oracle.jdbc.driver.DatabaseError.newSQLException(DatabaseError.java:110)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:171)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:496)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:411)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:490)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:202)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:33)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:465)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Main.main(Main.java:21)

Within my server I have used the command (logged on as sys) SQL> select instance from v$thread; (it returns) Instance--> xe

What could I be doing incorrect?

Thanks!

P.S. I have also tried 127.0.0.1 instead of localhost

Answer 1

Check if listener.ora file under the <ORACLE_HOME>\admin\NETWORK directory has the following value:

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

Answer 2

Instead of String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + ":" + sid;

use this:

String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + "/" + sid;

Answer 3

replace xe with database name which you have set during installation, you will surely get success

if you forgot the dbname it could be retreived from file tnsnames.ora in your oracle directory

Answer 4

I faced same problem while connecting to oracle rac. I changed the url from port:servicename to port/servicename and it worked for me.

Answer 5

I'm going to guess that the TNS listener has started, but the database instance started up before the listener did.

When the database instance starts up, it will register itself with the TNS listener. However, if there's no listener to register with, it can't do this. When the listener starts up, it doesn't check to see whether the instances it knows about have started up.

I can provide a demonstration. I'm using Oracle 11g XE Beta on Windows 7. Initially, the OracleServiceXE service is running but OracleXETNSListener service is not.

I ran your database connection code and I got the following error:

Exception in thread "main" java.sql.SQLRecoverableException: IO Error: The Network Adapter could not establish the connection

If you're getting a ORA-12505 error, then clearly your TNS listener is running.

I then started the TNS listener and re-ran your database connection code. I got the following output this time: (I've renamed your class and changed the username and password within it, but other than that, the code within it is the same):

C:\Users\Luke\stuff>java DbConnTest
Exception in thread "main" java.sql.SQLException: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
[stacktrace snipped]

(This error isn't identical to yours: I didn't get a The Connection descriptor used by the client was: section in it. I'm not 100% sure why.)

In the case above, the fix is connect to SQL*Plus as SYS and run ALTER SYSTEM REGISTER. This registers the instance with the listener:

C:\Users\Luke\stuff>sqlplus / as sysdba

SQL*Plus: Release 11.2.0.2.0 Beta on Sun Jul 24 11:13:57 2011

Copyright (c) 1982, 2010, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Express Edition Release 11.2.0.2.0 - Beta

SQL> alter system register;

System altered.

SQL> exit
Disconnected from Oracle Database 11g Express Edition Release 11.2.0.2.0 - Beta

After doing this, I was able to connect to the database:

C:\Users\Luke\stuff>java DbConnTest
Success