unable to connect to oracle database

[N.srinivas chowdary]

hi,
iam able to compile the class,i have set the path to classes12.zip,but when iam running the class iam getting the following error.plz help me in this regard.
Exception in thread "main" java.sql.SQLException: ORA-01034: ORACLE not availabl
e

at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:169)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:208)
at oracle.jdbc.ttc7.O3log.receive1st(O3log.java:429)
at oracle.jdbc.ttc7.TTC7Protocol.logon(TTC7Protocol.java:248)
at oracle.jdbc.driver.OracleConnection.<init>(OracleConnection.java:252)

at oracle.jdbc.driver.OracleDriver.getConnectionInstance(OracleDriver.ja
va:365)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:260)
at java.sql.DriverManager.getConnection(DriverManager.java:512)
at java.sql.DriverManager.getConnection(DriverManager.java:171)
at DBTest.main(DBTest.java:11)

[David O'Meara]

ORA-01034: ORACLE not available

Is oracle available? Make sure it is running and able to be accessed by (for example) sqlplus and SquirrelSQL

Dave

[Adam Richards]

The problem is not Java in this case. You are loading the Oracle driver correctly, or you wouldn't be getting an Oracle error message. Here's the description of the error, from the official Oracle documentation at
(http://download-west.oracle.com/docs/cd/A87860_01/doc/server.817/a76999/e900.htm#1656):

ORA-01034 ORACLE not available

Cause: Oracle was not started. Possible causes include the following:

The SGA requires more space than was allocated for it.

The operating-system variable pointing to the instance is improperly defined.

Action: Refer to accompanying messages for possible causes and correct the problem mentioned in the other messages. If Oracle has been initialized, then on some operating systems, verify that Oracle was linked correctly. See the platform-specific Oracle documentation.