Java Data Objects (JDO)

The last persistence technology that you will be looking at today, Java Data Objects (JDO), aims high and aims low. That is, it is intended both for use within embedded devices (J2ME), but also for use within J2EE environments. In a J2EE environment, JDO can either supplement or supplant Entity EJBs. If supplementing Entity EJBs, the application of JDO may be hidden when CMP is being employed (that is, the EJB vendor uses JDO but the bean provider is unaware of this), or it can be used by the bean provider directly if BMP is in use. If supplanting Entity EJBs, JDO can be used directly from Session EJBs and servlets.

The overriding objective of JDO is to provide persistence transparency. In other words, the objects that ...

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