Hibernate vs JPA vs JDO - pros and cons of each?
I'm familiar with ORM as a concept, and I've even used nHibernate several years ago for a .NET project; however, I haven't kept up with the topic of ORM in Java and haven't had a chance to use any of these tools.
But, now I may have the chance to begin to use some ORM tools for one of our applications, in an attempt to move away from a series of legacy web services.
I'm having a hard time telling the difference betweeen the JPA spec, what you get with the Hibernate library itself, and what JDO has to offer.
So, I understand that this question is a bit open-ended, but I was hoping to get some opinions on:
- What are the pros and cons of each?
- Which would you suggest for a new project?
- Are there certain conditions when it would make sense to use one framework vs the other?
Answer
Some notes:
- JDO and JPA are both specifications, not implementations.
- The idea is you can swap JPA implementations, if you restrict your code to use standard JPA only. (Ditto for JDO.)
- Hibernate can be used as one such implementation of JPA.
- However, Hibernate provides a native API, with features above and beyond that of JPA.
IMO, I would recommend Hibernate.
There have been some comments / questions about what you should do if you need to use Hibernate-specific features. There are many ways to look at this, but my advice would be:
If you are not worried by the prospect of vendor tie-in, then make your choice between Hibernate, and other JPA and JDO implementations including the various vendor specific extensions in your decision making.
If you are worried by the prospect of vendor tie-in, and you can't use JPA without resorting to vendor specific extensions, then don't use JPA. (Ditto for JDO).
In reality, you will probably need to trade-off how much you are worried by vendor tie-in versus how much you need those vendor specific extensions.
And there are other factors too, like how well you / your staff know the respective technologies, how much the products will cost in licensing, and whose story you believe about what is going to happen in the future for JDO and JPA.