Hibernate vs JPA vs JDO - pros and cons of each?

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+17 Q:

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?

JDO is dead, Hibernate is advance JPA, JPA is common api for main ORM players. Id sujest you go with JPA and Hibernate(JPA is enough most of the time), if you ever need more advance power of ORM you can use Hibernate specfic annotations. JPA + Hibernate is most common choice.

Hibernate Validator is very interesting project that let you use annotation to validate your entity beans.

http://www.hibernate.org/hib_docs/validator/reference/en/html_single/index.html#d0e46

01 2009-02-09 22:05:05

Why is JDO "dead"?

matt b 2009-02-09 23:37:26

because nobody is using it, really.

01 2009-02-10 15:58:15

Clearly evidenced by Google AppEngine for Java, ... many many people are using JDO. End the FUD

DataNucleus 2009-06-12 07:56:26

I wonder what would one say if Google hadn't chosen JDO for GAE/J? Personally, I don't think this is enough for a comeback.

Pascal Thivent 2010-03-19 10:38:52

Hibernate is indeed good. But 'JDO is dead' is a bad reason and not true.

JavaRocky 2010-04-03 09:21:05

+15 A:

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.
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.

toolkit 2009-02-09 22:14:19

toolkit, nice and short. Another point worth mentioning is that JPA doesn't prevent from using implementation specific features if necessary. That means that JPA lets you use any Hibernate feature when Hibernate is an implementation.

grigory 2010-03-12 04:11:21

What would be the advantages of using JPA if I need some specific feature from Hibernate?

Bruno Reis 2010-05-15 14:53:53

An important note that should be added:While JPA and JDO both have excellent support for RDBMSes JDO is 'datastore' agnostic and so is not limited to the RDBMS world. With the ground swell of NoSQL at the moment a person would be wise to consider using a persistence standard that avoids locking their apps to the traditional *SQL world.JDO applications can easily be deployed non RDBMS datastores. Full list of supported datastores can be found at:http://www.datanucleus.org/products/accessplatform/datastores.html

Golfman 2010-08-02 21:16:57

@Golfman why choose based on what *might* happen? There's nothing to stop you from rolling in something else later if you ever did end up needing NoSQL support... KISS

TM 2010-08-09 16:55:59

@Bruno - when you are using non-Hibernate-specific parts of Hibernate, you *are* using JPA. Obviously, the advantage of restricting yourself to pure JPA is that you can switch to another JPA implementation more easily.

Stephen C 2010-09-19 02:58:35

Funnily enough, the selling point of JDO has always been that it was datastore agnostic, so you could switch to a OO database. Did it happen? No, for a lot of obvious reasons. Same player, shoot again: with JDO, you could switch to a NoSQL database. Will it happen? I bet it won't and I can't wait for the NoSQL soufflé to fall. But, sure, you can switch to a spreadsheet datastore,...

Pascal Thivent 2010-10-02 21:10:11

+5 A:

I've been looking into this myself and can't find a strong difference between the two. I think the big choice is in which implementation you use. For myself I've been considering the DataNucleus platform as it is a data-store agnostic implementation of both.

tapi 2009-02-09 22:29:19

+1 for DataNucleus, not for the answer.

WolfmanDragon 2009-02-09 22:31:27

+11 A:

Which would you suggest for a new project?

I would suggest neither! Use Spring DAO's JdbcTemplate together with StoredProcedure, RowMapper and RowCallbackHandler instead.

My own personal experience with Hibernate is that the time saved up-front is more than offset by the endless days you will spend down the line trying to understand and debug issues like unexpected cascading update behaviour.

If you are using a relational DB then the closer your code is to it, the more control you have. Spring's DAO layer allows fine control of the mapping layer, whilst removing the need for boilerplate code. Also, it integrates into Spring's transaction layer which means you can very easily add (via AOP) complicated transactional behaviour without this intruding into your code (of course, you get this with Hibernate too).

oxbow_lakes 2009-02-09 22:44:25

this is clearly anti- object-relational mapping (ORM) choice driven by large user and code base accumulated since ODBC times (early 90s) (read legacy). There is no reason not to use JDBC (with or without Spring) unless you choose to move on and use ORM framework. Think of those people who one day decided to ditch FORTRAN to use C or Pascal.

grigory 2010-03-10 06:34:52

@grigory - I speak with much experience of wasting days trying to understand Hibernate issues, such as cascading updates/deletes, ridiculously inefficient query structures etc. ORM solutions are a "quick-win" for those with insufficient understanding of relational databases. As such, it is unlikely that knowledge of Hibernate alone will result in a good end-product. It's my experience that, over the project lifecycle, Hibernate (and ORM by extension) costs more time than it saves

oxbow_lakes 2010-06-04 08:13:14

sorry that you had such poor experience with Hibernate. I am coming from heavy database/SQL/stored procedure/JDBC school myself. I can't say I am convert - every technology above still has a place to be. But for general purpose Java 3-tier application (no matter what size) first choice is an ORM technology - preferably JPA 2. Others are to be considered based on such factors legacy code, integration, expertise, batch-heavy requirements, real-time performance etc. which may steer (or may not) approach towards different database technology stack.

grigory 2010-06-04 16:04:49

I completely disagree with "quick-win" definition above - just grab Hibernate in Action (http://stackoverflow.com/questions/96729/what-are-the-best-books-for-hibernate-jpa/96865#96865) (and it's JPA 1, with JPA 2 it gets only better) to fully understand power and coverage this technology has.

grigory 2010-06-04 16:05:33

@oxbow_lakes: I'm with you on this. I'm a developer DBA who is helping Hibernate using Java guys to troubleshoot this black box. Hibernate speeds development of course, but you simply shift the bottleneck. ORMs have their place (a means, not the end) but respect the RDBMS. Mind you, I'll always have a job if folk want to use ORMs...

gbn 2010-08-24 16:10:45

+7 A:

JDO is dead

JDO is not dead actually so please check your facts. JDO 2.2 was released in Oct 2008 JDO 2.3 is under development.

This is developed openly, under Apache. More releases than JPA has had, and its ORM specification is still in advance of even the JPA2 proposed features

DataNucleus 2009-02-21 07:45:36

People are most certainly using it, as evidenced by the many users that DataNucleus has, never mind Xcalia, Kodo. You miss the basic idea that JDO and JPA are not filling the same market. JPA is exclusively RDBMS. JDO is datastore agnostic and is used for RDBMS, but also LDAP, XML, Excel, OODBMs etc

DataNucleus 2009-02-22 09:19:18

+5 A:

I am using JPA (OpenJPA implementation from Apache which is based on the KODO JDO codebase which is 5+ years old and extremely fast/reliable). IMHO anyone who tells you to bypass the specs is giving you bad advice. I put the time in and was definitely rewarded. With either JDO or JPA you can change vendors with minimal changes (JPA has orm mapping so we are talking less than a day to possibly change vendors). If you have 100+ tables like I do this is huge. Plus you get built0in caching with cluster-wise cache evictions and its all good. SQL/Jdbc is fine for high performance queries but transparent persistence is far superior for writing your algorithms and data input routines. I only have about 16 SQL queries in my whole system (50k+ lines of code).

2009-04-16 21:08:57

+6 A:

JDO is having advanced features than JPA see http://db.apache.org/jdo/jdo_v_jpa.html

Sandeep Manne 2010-03-10 05:45:24

Still, JPA has more success for object to RDBMS persistence so I'd be tempted to say that people don't care of these features. What's the point of advanced feature if people aren't using them? "JDO: Hey! Look at me, I'm great, I can touch my nose with my tongue! JPA: Yeah, yeah, so what?".

Pascal Thivent 2010-03-18 20:41:15

+1 A:

I've used Hibernate (JPA implementation) and JPOX (JDO implementation) in the same project. JPOX worked ok, but ran into bugs fairly quickly, there where some Java 5 language features it did not support at the time. It had problems playing nice with XA transactions. I was generating the database schema from the JDO objects. It wanted to connect to a database every time which is annoying if your Oracle connection happens not be working.

We then switched to Hibernate. We toyed around with just using pure JPA for awhile, but we needed to use some of the Hibernate specific features to do the mapping. Running the same code on multiple databases is very easy. Hibernate seems to cache objects aggressively or just have strange caching behavior at times. There are a few DDL constructs Hibernate can not handle and so they are defined in an additional file that is run to initialize the database. When I've run into a Hibernate problem there are often many people that have run into the same problem which makes googling for solutions easier. Finally, Hibernate seems to be well designed and reliable.

Some other responders have suggested just using SQL. The real killer use case for object relational mapping is testing and development. The databases that are built to handle large volumes of data are typically expensive and or they are difficult to install. They are difficult to test with. There are plenty of in-memory Java databases that can be used to test with, but are typically useless for production. Being able to use a real, but limited database, will increase development productivity and code reliability.

Sean McCauliff 2010-03-10 06:24:19

As far as I can tell, JPOX changed name to DataNucleus (and has had releases since then).

Donal Fellows 2010-08-14 15:57:31

+8 A:

Make sure you evaluate the DataNucleus implementation of JDO. We started out with Hibernate because it appeared to be so popular but pretty soon realized that it's not a 100% transparent persistence solution. There are too many caveats and the documentation is full of 'if you have this situation then you must write your code like this' that took away the fun of freely modeling and coding however we want. JDO has never caused me to adjust my code or my model to get it to 'work properly'. I can just design and code simple POJOs as if I was going to use them 'in memory' only, yet I can persist them transparently.

The other advantage of JDO/DataNucleus over hibernate is that it doesn't have all the run time reflection overhead and is more memory efficient because it uses build time byte code enhancement (maybe add 1 sec to your build time for a large project) rather than hibernate's run time reflection powered proxy pattern.

Another thing you might find annoying with Hibernate is that a reference you have to what you think is the object... it's often a 'proxy' for the object. Without the benefit of byte code enhancement the proxy pattern is required to allow on demand loading (i.e. avoid pulling in your entire object graph when you pull in a top level object). Be prepared to override equals and hashcode because the object you think you're referencing is often just a proxy for that object.

Here's an example of frustrations you'll get with Hibernate that you won't get with JDO:

http://blog.andrewbeacock.com/2008/08/how-to-implement-hibernate-safe-equals.html
http://burtbeckwith.com/blog/?p=53

If you like coding to 'workarounds' then, sure, Hibernate is for you. If you appreciate clean, pure, object oriented, model driven development where you spend all your time on modeling, design and coding and none of it on ugly workarounds then spend a few hours evaluating JDO/DataNucleus. The hours invested will be repaid a thousand fold.

Golfman 2010-03-11 11:30:29

And as we all know, enhancement is precisely why JDO has been so massively adopted!

Pascal Thivent 2010-03-18 21:57:08

The well publicized FUD and astroturfing executed by key Hibernate players in the early days in relation to JDO is nothing short of dishonest and disgusting and no doubt had some affect on JDO's adoption. These days developers know that byte code enhancement is not a problem at all and often use it for many different purposes other than persistence. The new ASM byte code enhancement library is so lightning fast you don't even have time to take a breath before it's done.

Golfman 2010-03-19 04:47:01

Pascal Thivent 2010-03-19 09:56:31

To illustrate my words (yet another post that illustrates the pain that people were feeling during development or why Hibernate did win the battle): http://www.mail-archive.com/[email protected]/msg04107.html. It seems obvious to me that reflection/cglib was a practical answer to people's problems (and people don't care if an API is conceptually superior if it's a pain to use) and I don't see any Hibernate key players here, just users. So at the end I wonder who is spreading FUD actually...

Pascal Thivent 2010-03-19 12:34:57

Well this is certainly not like the old days where there would have been at least 17 different pro Hibernate FUD posts (yet only coming from 3 different IP addresses. Do the maths people =) ).

Golfman 2010-03-24 02:44:00

"and people don't care if an API is conceptually superior if it's a pain to use".It sounds like you've never enlightened yourself by actually using JDO because if you had you wouldn't say it's a pain to use. After using Hibernate I switched "to JDO" because I found the API *easier* to use and found JDOs 'transparent persistence' much less of a pain than what Hibernate's reflection/cglib solution had to offer.Here's some details for those interested in discerning FUD from facts:http://www.datanucleus.org/products/accessplatform_2_0/bytecode_enhancement.html

Golfman 2010-03-24 03:13:09

Taking my sentence out of its context is weak sauce. I was clearly referring to the mail cited as reference and, **at that time**, JDO was a pain (and I did experiment this pain myself), Hibernate was a better answer and this is why it took the market, not because of 17 pro Hibernate posts (what a joke!) nor marketing. Not recognizing this is ridiculous (especially since you're repeating yourself - yes I've read your posts on TSS and so on). And because my clients are using JPA now (they don't even think about JDO), because they want to use a widely used/supported/tested JPA provider, so do I.

Pascal Thivent 2010-03-25 15:10:19

Pain is a very subjective thing: While some people might regard waiting an extra 1 or 2 seconds after a compile for the enhancement process back then (these days it's an order of magnitude faster than it was) as painful others might see restrictions and constraints on their design/modeling and coding when using a persistence solution that isn't 100% transparent a more significant pain with, depending on the expressiveness and complexity of their domain model, more time committed to working around the imposed constraints. I personally found that more painful. Different pain for different people

Golfman 2010-04-02 01:46:52

@Golfman maybe it's just Kodo, but I really hate JDO, and so does every single one of my coworkers. It's to the point where half of them would rather use straight JDBC. And just to be clear, no one hates it because of the extra compile step. They hate it because it's a pain to write code with and a pain to optimize queries with. Just my personal experience.

TM 2010-08-09 16:44:00

+5 A:

Anyone who says that JDO is dead is an astroturfing FUD monger and they know it.

JDO is alive and well. The specification is still more powerful, mature and advanced than the much younger and constrained JPA.

If you want to limit yourself to only what's available in the JPA standard you can write to JPA and use DataNucleus as a high performance, more transparent persistence implementation than the other implementations of JPA. Of course DataNucleus also implements the JDO standard if you want the flexibility and efficiency of modeling that JDO brings.

Golfman 2010-03-11 11:42:12

Or you use another (fine) implementation with a much bigger and consequently more responsive community. Yes, some people do care of that too.

Pascal Thivent 2010-03-18 20:43:25

That's a good point you make. When people use the implementation you refer to the need for lots of support and frequent explanations of 'best practice workarounds' and 'how do I make it perform fast and use less memory' will be most important =]

Golfman 2010-03-19 04:40:06

And you talk about FUD >:) Funny.

Pascal Thivent 2010-03-19 09:40:59

Your comment seems to presume that I haven't used both Hibernate and JDO.

Golfman 2010-03-24 02:47:56

This thread seems to have an awful lot of references from a couple people to how great DataNucleus is. Please don't use this place as your advertising platform.

TM 2010-08-09 17:10:52

Nothing surprising from Golfman who is pasting the same desperate marketing stuff over and over in every thread involving JPA or DataNucleus (that he is using [since 1996](http://www.theserverside.com/news/thread.tss?thread_id=60388#337187), before [it even existed](http://www.jpox.org/docs/project/history.html)!).

Pascal Thivent 2010-08-23 19:29:32

Hay guise what's going on in here?

Will 2010-08-24 13:41:41

@Will: Betamax vs VHS?

gbn 2010-08-24 16:04:16

@gbn ouch. Ouch.

Will 2010-08-24 16:44:07

Whoops! :) That was supposed to be 2006! Still debugging my time machine in my spare time.

Golfman 2010-09-06 01:43:13

I've not used JDO but understand it employs byte-code enhancement. Which makes me nervous.

I believe JPA is the new Java persistence standard that was 'inspired' by Hibernate and so JPA is a subset of Hibernate (at least for now). It replaces Entity EJBs.

The project I'm on is a desktop app that will be data intensive so I'm going to give Spring DAO a try. I want to keep it simple.

Peter L 2010-06-03 23:48:12

JPA wasn't merely 'inspired' by Hibernate - its reason for existence was an attempt to play the "Hibernate complies with a standard also" game.We know by some of the bizarre contraints in JPA that it was written in an attempt to provide a standard that Hibernate was capable of implementing instead of the typical process whereby people come up with a powerful, well thought out, brilliantly designed, unconstrained standard which is then gets implemented. The community went through that process early in this decade and created a most excellent standard called JDO.

Golfman 2010-08-02 20:39:15

If you're using Maven, bytecode enhancement isn't something to fear: you just have an extra plugin to add to your POM. (The lack of properly clear instructions on exactly what to do, now *that* matters more, but it's par for the course when dealing with Maven.)

Donal Fellows 2010-08-14 15:59:55

+4 A:

I have recently evaluated and picked a persistence framework for a java project and my findings are as follows:

What I am seeing is that the support in favour of JDO is primarily:

you can use non-sql datasources, db4o, hbase, ldap, bigtable, couchdb (plugins for cassandra) etc.
you can easily switch from an sql to non-sql datasource and vice-versa.
no proxy objects and therefore less pain with regards to hashcode() and equals() implementations
more POJO and hence less workarounds required
supports more relationship and field types

and the support in favour of JPA is primarily:

more popular
jdo is dead
doesnt use bytecode enhancement

I am seeing a lot of pro-JPA posts from JPA developers who have clearly not used JDO/Datanucleus offering weak arguments for not using JDO.

I am also seeing a lot of posts from JDO users who have migrated to JDO and are much happier as a result.

In respect of JPA being more popular, it seems that this is due in part due to RDBMS vendor support rather than it being technically superior. (Sounds like VHS/Betamax to me).

JDO and it's reference implementation Datanucleus is clearly not dead, as shown by Google's adoption of it for GAE and active development on the source-code (http://sourceforge.net/projects/datanucleus/).

I have seen a number of complaints about JDO due to bytecode enhancement, but no explanation yet for why it is bad.

In fact, in a world that is becoming more and more obsessed by NoSQL solutions, JDO (and the datanucleus implementation) seems a much safer bet.

I have just started using JDO/Datanucleus and have it set up so that I can switch easily between using db4o and mysql. It's helpful for rapid development to use db4o and not have to worry too much about the DB schema and then, once the schema is stabilised to deploy to a database. I also feel confident that later on, I could deploy all/part of my application to GAE or take advantage of distributed storage/map-reduce a la hbase /hadoop / cassandra without too much refactoring.

I found the initial hurdle of getting started with Datanucleus a little tricky - The documentation on the datanucleus website is a little hard to get into - the tutorials are not as easily to follow as I would have liked. Having said that, the more detailed documentation on the API and mapping is very good once you get past the initial learning curve.

The answer is, it depends what you want. I would rather have cleaner code, no-vendor-lock-in, more pojo-orientated, nosql options verses more-popular.

If you want the warm fussy feeling that you are doing the same as the majority of other developers/sheep, choose JPA/hibernate. If you want to lead in your field, test drive JDO/Datanucleus and make your own mind up.

Tom 2010-09-27 10:39:07

I'd really like you to elaborate your points instead of repeating things like a parrot (yes, that's exactly what you are doing). According to your other posts, you don't have much experience with Object Persistence in general and, I'm not really sure you ever used neither Hibernate, nor JPA, nor JDO. So, at the end, you're just turning this thread a bit more into desperate advertising, reusing others (sometimes biased and invalid) arguments.

Pascal Thivent 2010-10-02 17:03:50

Actually, just like I said, I was just giving my impressions of what I had discovered while trying to pick a solution. Yes I am a beginner in Java, why should that be that relavent? You, on the other hand have posted a number of times stating your opinion that JDO is dead without offering any facts or proof to substantiate it and not acknowledging the technical areas where JDO is clearly superior. You obviously have something personal against JDO/Datanucleus and are using these threads as a means to perpetuate your anti-JDO stance.

Tom 2010-10-03 16:12:01

Tom, just look at Google Trends, or indeed.com, and tell me if JDO is a success from an adoption point of view (adoption is IMO what makes a standard alive, not the number of versions of the spec). I have used many ORMs since 2002, including Toplink, JDO 1.0, Hibernate and JPA and I don't feel sorry to say that JDO 1.0 has been an horrible experience, which is precisely why Hibernate took the market of RDBMS persistence. And whether you like Hibernate approach or not, standardizing a widely adopted solution has been a good move for Java EE and I'm happy it happened.

Pascal Thivent 2010-10-05 08:10:15

So yes, JPA is younger and has less (I'm not denying that), but I *am* satisfied with it for RDBMS persistence and prefer its API, query language, ease of use, simplicity, etc over JDO. And I believe that this is what makes JPA successful and I don't feel guilty for writing it. Likewise, you're free to use JDO and I don't have any problem with people keeping JDO under artificial respiration. However, I'm tired by the conspiracy theorists and those using SO for advertising should read the [FAQ](http://stackoverflow.com/faq#promotion) again. Personally, I'm not affiliated, I'm just a user.

Pascal Thivent 2010-10-05 08:11:33

Pascal - you are arguing yourself into a corner here. I think you are missing the point of the Advertising section of the FAQ. The OP asked for opinions about 2 technologies. It is inviting those supporting either side to come forward and present their constructive criticisms/recommendations. For Andy/Datanucleus and other JDO users to highlight JDO positives and defend against criticisms is no more advertising than someone else here recommending to use hibernate.

Tom 2010-10-05 11:01:11

You might do well to refer to the section of the FAQ that says 'Be Nice' for your posts on this topic have been accusatorial, confrontational or plain rude.Your first was a sarcastic comment about enhancement. Second; a rant on the difficulties of early implementations and is no longer relevant. Third was a childish mocking and insult to those who might prefer not to use RDBMS. Fourth was sarcastic mocking of someone who has different views to you. Fifth was an attack; calling me a parrot. Do you consider this 'Being nice'?

Tom 2010-10-05 11:01:26

If you had a horrible experience with JDO, then explain what was horrible, acknowledge that it was with an earlier version and things may have been improved since then. You need to also recognise that others may have different needs to you. Just because you are 'satisfied' with JPA and want to use a RDBMS doesn’t mean that others are.Maybe in your haste to increase your reputation you have lost sight of what that reputation is there to award? ps. As a developer you should really be interested in the wellbeing of such projects as that is what drives innovation and reduces vendor-lock in.

Tom 2010-10-05 11:01:52

This will be my final comment. 1. The point about advertising was not specific to this question. 2. If you think the opinions I expressed are inappropriate, report them. But I fully assume and I don't see anything dishonest in what I said (contrarily to some comments to which I responded). 3. No, sorry, I'm not going to summarize 8+ years of persistence war to explain why I'm not using JDO today, that would be too long. And what I meant is that (most) users, not only me, are satisfied with a RDBMS datastore (Google offering paid SQL hosting is another hint).

Pascal Thivent 2010-10-06 06:44:24

4. I don't see what my participation to SO has to do with all this. I like problem solving, sharing solutions, etc but still have opinions. Do I need to add that rep isn't real? 5. I have no problem with competition (it's good for users). However, the "Hibernate/JPA/JBoss is evil" attitude is irritating me. I'm happy of what they did to Java. 6. I'm done now, if you want more details, there are 7 years of threads to read on TSS and all over the net.

Pascal Thivent 2010-10-06 06:45:53

This will be my final response :) .. 1. If it wasn't relavent to question why raise it? 2. I never questioned your honesty, I said you were not being nice to other posters and that you contradicted yourself. 3. no one suggested you summarize 8+ years - but back up your statements with facts and examples rather than subjective statements that are likely to offend. 5. Where are the 'hibernate/jpa/jboss is evil' attitude on this post? I dont see it. I only see your anti-JDO comments.

Tom 2010-10-08 19:26:03

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Hibernate vs JPA vs JDO - pros and cons of each?

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