The two persistence standards in Java have very similar API’s on the face of it. Here we give a comparison of the method calls and their equivalent in the other API.

    Operation JDO JPA
    Persist Object pm.makePersistent() em.persist
    Update Object pm.makePersistent() em.merge()
    Remove Object pm.deletePersistent() em.remove()
    Retrieve Object pm.getObjectById()
    pm.getExtent()    		 em.find()
    Refresh Object pm.refresh() em.refresh()
    Detach single Object pm.detachCopy() em.detach()
    Flush changes pm.flush() em.flush()
    Access transaction pm.currentTransaction() em.getTransaction()
    New Query pm.newQuery() em.createQuery()
    New Named Query pm.newNamedQuery() em.createNamedQuery()
    New SQL Query pm.newQuery() em.createNativeQuery()