log4j在控制台上輸出了這樣一個WARN：
14:34:32,171 WARN SettingsFactory:126 - Could not obtain connection metadata
java.sql.SQLException: 不支持的特性
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:179)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:269)
at oracle.jdbc.dbaccess.DBError.throwUnsupportedFeatureSqlException(DBError.java:689)
at oracle.jdbc.OracleDatabaseMetaData.supportsGetGeneratedKeys(OracleDatabaseMetaData.java:4180)
at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:123)
at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2119)
at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2115)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1339)
at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:867)
at TeacherTest.main(TeacherTest.java:21)
14:34:32,562 INFO SchemaUpdate:155 - Running hbm2ddl schema update
14:34:32,562 INFO SchemaUpdate:167 - fetching database metadata
14:34:32,906 INFO SchemaUpdate:179 - updating schema
14:34:33,015 INFO TableMetadata:65 - table found: SCOTT.STUDENT
14:34:33,015 INFO TableMetadata:66 - columns: [stu_name, sex, stu_id, age]
14:34:33,015 INFO TableMetadata:68 - foreign keys: []
14:34:33,015 INFO TableMetadata:69 - indexes: [sys_c007660]
14:34:33,046 INFO TableMetadata:65 - table found: SCOTT.T_TEACHER
14:34:33,046 INFO TableMetadata:66 - columns: [titleenum, c_age, c_title, c_id, c_sex, c_name]
14:34:33,046 INFO TableMetadata:68 - foreign keys: []
14:34:33,046 INFO TableMetadata:69 - indexes: [sys_c007663]
14:34:33,046 INFO SchemaUpdate:217 - schema update complete
Hibernate: insert into t_teacher (c_age, c_name, c_sex, c_title, titleEnum, c_id) values (?, ?, ?, ?, ?, ?)
這個warn不影響最後的結果，數據庫裏面也插進去數據了，但是，出現這個異常，看著心裡不爽，想解決這個問題！
用google搜索了下，很多開發者都遇到了這個問題，有解決的，說是數據庫驅動出了問題，我就想換個驅動試試。
在oracle官網上，oracle9i 9.2.0.4 jdbc的驅動，下載下來，將原來的替換掉，這個warn就消失了！哈哈