Weblogic LogicalConnection无法强制转换为oracle.jdbc.OracleConnection

Question

在创建oracle.sql.Clob对象时出现ClassCastException。

错误：

java.lang.ClassCastException: weblogic.jdbc.wrapper.JTAConnection_weblogic_jdbc_wrapper_XAConnection_oracle_jdbc_driver_LogicalConnection cannot be cast to oracle.jdbc.OracleConnection
    at oracle.sql.CLOB.createTemporary(CLOB.java:868)
    at oracle.sql.CLOB.createTemporary(CLOB.java:828)

Java代码：

InitialContext ic = new InitialContext();
DataSource dsds = (DataSource)ic.lookup("valid_ds_name");
Connection conn = ds.getConnection();
CLOB clob = CLOB.createTemporary(connection, false, CLOB.MODE_READWRITE);

weblogic.xml

<?xml version="1.0" encoding="UTF-8"?>
<weblogic-web-app xmlns="http://xmlns.oracle.com/weblogic/weblogic-web-app">
  <context-root>/PNPRESTAPI</context-root>
  <container-descriptor>
        <prefer-web-inf-classes>true</prefer-web-inf-classes>
    </container-descriptor>
</weblogic-web-app> 

包括的罐子：

ojdbc6.jar