I need use different isolation level by transaction. For what kind of isolation level has oracle support ?

1. READ_COMMITED
2. READ_UNCOMMITED
3. REPEATABLE_READ
4. SERIALIZABLE

Or how could I use all types of isolation level ?
(I want to use it in Java and DatabaseMetaData.supportsIsolationLevel told me, that second and third level doesn't supports. It is possible to use this levels in Oracle9i database ?)