Ok, I would like to answer my question. As i have understood what wrong I have done.
I created 3 database instances. So I should start 3 database instance one by one.
So how do we start 3 database instances?
every database instance has its own SID, so before you start the database, you need to put the
correct SID for that.
this is how i did it
ora112@localhost ~]$ ORACLE_SID=JIP02T
[ora112@localhost ~]$ ls
db.rsp Desktop summary
[ora112@localhost ~]$ sqlplus '/as sysdba'
SQL*Plus: Release 11.2.0.3.0 Production on Thu Dec 27 01:23:35 2012
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 5511979008 bytes
Fixed Size 2238056 bytes
Variable Size 1107298712 bytes
Database Buffers 4378853376 bytes
Redo Buffers 23588864 bytes
Database mounted.
Database opened.
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64 bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Then i need to set the SID for other database instance.
ora112@localhost ~]$ ORACLE_SID=JIP04K
[ora112@localhost ~]$ ls
db.rsp Desktop summary
[ora112@localhost ~]$ sqlplus '/as sysdba'
SQL*Plus: Release 11.2.0.3.0 Production on Thu Dec 27 01:23:35 2012
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 5511979008 bytes
Fixed Size 2238056 bytes
Variable Size 1107298712 bytes
Database Buffers 4378853376 bytes
Redo Buffers 23588864 bytes
Database mounted.
Database opened.
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64 bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
There after i just started the oracle listener, oracle listener is opened on port 1521.
So, using sql developer, i created 2 database connections to the two database instances using same port number 1521.
