%META:TOPICPARENT{name="ErrorMessagesC"}%

= Error Message: {{{Connection failed: java.net.UnknownHostException: ODBC}}} =

Usually seen in a large block of Java error text, such as this --
{{{
java.sql.SQLException: [OpenLink][OPLJDBC3]Connection failed: java.net.UnknownHostException: ODBC
at openlink.jdbc3.OPLMessage.makeException(Unknown Source)
at openlink.jdbc3.Driver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
}}}

This message typically means our Type 3 Driver has been loaded instead of our Type 1 Driver.

You should generally have only one of the above drivers included in your <code>CLASSPATH</code> environment 
variable.  Choose the one best matched to your active JVM, and supporting the connection Type, 1 or 3, you require.

Our Type 1 JDBC Drivers have the following attributes --
| *Filename*                  | *Classname*                        | *JDBC Version*  | *Compatible JVMs*  |
| <code>opljdbc.jar</code>    | <code>openlink.jdbc.Driver</code>  |  JDBC 1         |  1.1.x             |
| <code>opljdbc2.jar</code>   | <code>openlink.jdbc2.Driver</code> |  JDBC 2         |  1.2.x and 1.3.x   |
| <code>opljdbc3.jar</code>   | <code>openlink.jdbc3.Driver</code> |  JDBC 3         |  1.4.x and 1.5.x   |
| <code>opljdbc4.jar</code>   | <code>openlink.jdbc4.Driver</code> |  JDBC 4         |  1.6.x             |
| <code>opljdbc4_1.jar</code> | <code>openlink.jdbc4.Driver</code> |  JDBC 4.1       |  1.7.x             |
| <code>opljdbc4_2.jar</code> | <code>openlink.jdbc4.Driver</code> |  JDBC 4.2       |  1.8.x             |

Our pure Type 3 JDBC Drivers have the following attributes --
| *Filename*                   | *Classname*                        | *JDBC Version*  | *Compatible JVMs*  |
| <code>megathin.jar</code>    | <code>openlink.jdbc.Driver</code>  |  JDBC 1         |  1.1.x             |
| <code>megathin2.jar</code>   | <code>openlink.jdbc2.Driver</code> |  JDBC 2         |  1.2.x and 1.3.x   |
| <code>megathin3.jar</code>   | <code>openlink.jdbc3.Driver</code> |  JDBC 3         |  1.4.x and 1.5.x   |
| <code>megathin4.jar</code>   | <code>openlink.jdbc4.Driver</code> |  JDBC 4         |  1.6.x             |
| <code>megathin4_1.jar</code> | <code>openlink.jdbc4.Driver</code> |  JDBC 4.1       |  1.7.x             |
| <code>megathin4_2.jar</code> | <code>openlink.jdbc4.Driver</code> |  JDBC 4.2       |  1.8.x             |


The pure Type 3 JDBC Drivers cannot be used for Type 1 connections.  The Type 1 Drivers are produced as hybrids, and may also be used for Type 3 connections.


== Evidence ==

* <code>CLASSPATH</code> environment variable