JDBC driver cannot be cast to javax.sql.DataSource or javax.sql.XADataSource in JBoss EAP

Environment

• Red Hat JBoss Enterprise Application Platform (EAP)
  • 6
  • 7

Issue

• Encountering a cast error using OracleDriver

  ... IJ000604: Throwable while attempting to get a new connection: null: javax.resource.ResourceException: IJ031084: Unable to create connection
          ...
  Caused by: javax.resource.ResourceException: IJ031089: Failed to load datasource: oracle.jdbc.driver.OracleDriver
          ...
  Caused by: java.lang.ClassCastException: oracle.jdbc.driver.OracleDriver cannot be cast to javax.sql.DataSource
          ...
  

• Encountering a cast error using DB2Driver

  ... IJ000453: Unable to get managed connection for java:java/myds
      ...
  Caused by: javax.resource.ResourceException: IJ000658: Unexpected throwable while trying to create a connection: null
      ...
  Caused by: javax.resource.ResourceException: Could not create connection
      ...
  Caused by: java.lang.ClassCastException: com.ibm.db2.jcc.DB2Driver cannot be cast to javax.sql.XADataSource
      ... 
  

Resolution

It may be helpful to review the use of DataSource, XADataSource and Driver implementations for JDBC access in JBoss EAP for context on the discussion below.

1. Avoid the use of the <datasource-class> property where possible as this is usually unnecessary.

2. If using only xa-datasource use only the xa-datasource-class property.

   • Note that the class specified using the <xa-datasource-class> property must implement the Content from docs.oracle.com is not included.javax.sql.XADataSource interface.

3. If using (non-XA) datasource pools use one of the following approaches:

   3.1. If the JDBC driver JAR does not declare a driver class in META-INF/services/java.sql.Driver, specify an appropriate vendor specific class explicitly using the <driver-class> property if the 3rd party jar includes a Driver implementation.

   • Note that the class specified using the <driver-class> property must implement the Content from docs.oracle.com is not included.java.sql.Driver interface.

   3.2. If the JDBC driver JAR includes no driver class, specify an appropriate vendor specific datasource class using the <datasource-class> property.

   • Note that the class specified using the <datasource-class> property must implement the Content from docs.oracle.com is not included.javax.sql.DataSource interface.

4. It is recommended that the <driver-class>, <datasource-class>, and/or <xa-datasource-class> properties be specified (once) within a <driver> entry in the <drivers> configuration rather than replicating the properties in each <datasource>...</datasource> or <xa-datasource>...</xa-datasource> specification.

Root Cause

One of the following is likely to be the source of the failure:

• In the driver configuration, a driver class was specified for the [xa-]datasource-class property:

                  <driver name="oracle" module="com.oracle.jdbc">
                      <datasource-class>oracle.jdbc.driver.OracleDriver</datasource-class> <!-- This is incorrect -->
                      <!-- OR -->
                      <xa-datasource-class>oracle.jdbc.driver.OracleDriver</xa-datasource-class> <!-- This is incorrect -->
                  </driver>
  

• In the (non-XA) datasource configuration, a driver class was specified for the datasource-class property:

                      <datasource-class>oracle.jdbc.driver.OracleDriver</datasource-class> <!-- This is incorrect -->
  

• In the xa-datasource configuration, a driver class was specified for the xa-datasource-class property:

                      <xa-datasource-class>oracle.jdbc.driver.OracleDriver</xa-datasource-class> <!-- This is incorrect -->
  

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