Java Database Connectivity (JDBC)

The following exception occurred when trying to get a connection from Oracle using thin driver. But,I could able to get the Connection through jdbc-odbc. But not with thin driver.

source code snippet:
public Connection getConnection() throws SQLException, ClassNotFoundException {

Class.forName("oracle.jdbc.driver.OracleDriver");
Connection con = DriverManager.getConnection("jdbc:oracle:thin:@oracle8i_installed_server_ipaddress:1521:servicename" , "msudev", "msudev");
System.out.println("Con: " + con);
return con;

}


Exception stack trace:

java.sql.SQLException: Io exception: Connection refused(DESCRIPTION=(TMP=)(VSNNUM=135294976)(ERR=12505)(ERROR_STACK=(ERROR=(CODE=12505)(EMFI=4))))

at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java)

at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java)

at oracle.jdbc.driver.OracleConnection.<init>(OracleConnection.java)

at oracle.jdbc.driver.OracleDriver.getConnectionInstance(OracleDriver.java)

at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java)

at java.sql.DriverManager.getConnection(DriverManager.java:517)

at java.sql.DriverManager.getConnection(DriverManager.java:177)

at com.sierra.msu.util.ConnectionPool.getConnection(ConnectionPool.java:190)

at com.sierra.msu.util.ConnectionPool.main(ConnectionPool.java:161)

Awaiting your response.
Thx in advance,
Usha.