What's the difference between JPA and Hibernate? [closed]

Question

I understand that JPA 2 is a specification and Hibernate is a tool for ORM. Also, I understand that Hibernate has more features than JPA 2. But from a practical point of view, what really is the difference?

I have experience using iBatis and now I'm trying to learn either Hibernate or JPA2. I picked up Pro JPA2 book and it keeps referring to "JPA provider". For example:

If you think a feature should be standardized, you should speak up and request it from your JPA provider

This confuses me so I have a few questions:

• Using JPA2 alone can I fetch data from DB by simply annotating my POJO's
• Is JPA2 supposed to be used with a "JPA Provider" e.g TopLink or Hibernate? If so, then what's the benefit of using JPA2 + Hibernate as compared to JPA2 alone, or compared to Hibernate alone ?
• Can you recommend a good practical JPA2 book. "Pro JPA2" seems more like a bible and reference on JPA2 (It doesn't get into Queries until the later half of the book). Is there a book that takes a problem/solution approach to JPA2?

Donne

The question about “the difference between JPA and Hibernate” is incorrect. Battle Hibernate vs JPA is pointless. It’s advisable to use any implementation of JPA with JPA API in order avoid implementing different ORM. – Dysgraphia

@Berguiga.M.Amine , If we have been already know that that above question is incorrect. We don't need ask anymore. I also interest on this topic. – Georgiana

I have a confusion with JpaTemplate used in spring "org.springframework.orm.jpa.JpaTemplate" it has his own functions like persist(),find(),merge() etc.then how the things are working without hibernate? – Ita

@nitinverma : That's realy a separate question. If you still need an answer, I suggest you ask your own question separately to attract more feedback. – Heirdom

Answer 1

As you state JPA is just a specification, meaning there is no implementation. You can annotate your classes as much as you would like with JPA annotations, however without an implementation nothing will happen. Think of JPA as the guidelines that must be followed or an interface, while Hibernate's JPA implementation is code that meets the API as defined by the JPA specification and provides the under the hood functionality.

When you use Hibernate with JPA you are actually using the Hibernate JPA implementation. The benefit of this is that you can swap out Hibernate's implementation of JPA for another implementation of the JPA specification. When you use straight Hibernate you are locking into the implementation because other ORMs may use different methods/configurations and annotations, therefore you cannot just switch over to another ORM.

For a more detailed description read my blog entry.

Firing

So, when you are using Hibernate with JPA, the {java.persistence } annotations will work or you will have to use {org.hibernate} annotations? – Consonant

'meaning there is no implementation' but there is concrete classes thus we can javax.persistence.entityManager.persist – Pernik

I just wanted to add that replacing one ORM with a different one is a very rare occasion, so you would probably never get this benefit out of using JPA. What you gain with JPA is a protocol, standards, naming and other conventions that you can use to communicate with others. – Broil

@Broil I agree, but in principle that is one of the selling points of a specification. – Firing

@Amruta to answer your question, when one is using Hibernate with JPA, the {java.persistence } annotations will work and no need to use {org.hibernate} annotations. – Halbert

@JavaGeek that is true as long as one's code is using only interface mentioned in JPA. If one uses features specific to hibernate then they have to use the org.hibernate annotation. more on this – Bahia

Answer 2

JPA is the dance, Hibernate is the dancer.

Hugues

hey but someone can use javax.persistence.entityManager instead of org.hibernate.session – Pernik

@Sangdol, this Wikipedia page should be helpful. – Demandant

but, Dancer(Hibernate) can perform without dance(JPA) isn't it :/ – Horotelic

JPA is the chess, Hibernate is the chessplayer – Camilacamile

This answer does not explain anything, just a vague saying. – Crystallite

can i say, JPA is an Interface and Hibernate is a class which implements that Interface? :p – Readability

JPA is a e.g. graphic template, and Hibernate is real brouchure. :P – Fortalice

This metaphor does not add understanding. If you already know the difference, you'll find it amuzing. If you don't know the difference, you will still not know it. – Carder

@NickVolynkin To be fair, that's why it is not the accepted answer. That being said, I think after reading the accepted answer and then reading this answer, it was very clear what the distinction is between the two. – Scorn

This is a very bad answer. Doesn't explain anything except the relation between them poorly. A number of upvotes are insane and make no sense. It's perfect as a comment or a summary of any different answer, but not as answer itself. – Urquhart

Excellent. This is so precise, explaining what are terms such as "specification" and "implementation".... – Pm

Hibernate is the Swiss Army Knife that was introduced by Rod Johnson to replace the unwieldy collection of tools you had to use for remote data objects (Cactus anyone? UGH). JPA is Sun (now Oracle) admitting their original collection of tools was dumb, then copying the original Swiss Army Knife with a series of JSR's. Only now the screwdriver is missing for some reason. – Natter

Answer 3

Some things are too hard to understand without a historical perspective of the language and understanding of the JCP.

Often there are third parties that develop packages that perform a function or fill a gap that are not part of the official JDK. For various reasons that function may become part of the Java JDK through the JCP (Java Community Process)

Hibernate (in 2003) provided a way to abstract SQL and allow developers to think more in terms of persisting objects (ORM). You notify hibernate about your Entity objects and it automatically generates the strategy to persist them. Hibernate provided an implementation to do this and the API to drive the implementation either through XML config or annotations.

The fundamental issue now is that your code becomes tightly coupled with a specific vendor(Hibernate) for what a lot of people thought should be more generic. Hence the need for a generic persistence API.

Meanwhile, the JCP with a lot of input from Hibernate and other ORM tool vendors was developing JSR 220 (Java Specification Request) which resulted in JPA 1.0 (2006) and eventually JSR 317 which is JPA 2.0 (2009). These are specifications of a generic Java Persistence API. The API is provided in the JDK as a set of interfaces so that your classes can depend on the javax.persistence and not worry about the particular vendor that is doing the work of persisting your objects. This is only the API and not the implementation. Hibernate now becomes one of the many vendors that implement the JPA 2.0 specification. You can code toward JPA and pick whatever compliant ORM vendor suits your needs.

There are cases where Hibernate may give you features that are not codified in JPA. In this case, you can choose to insert a Hibernate specific annotation directly in your class since JPA does not provide the interface to do that thing.

Source: http://www.reddit.com/r/java/comments/16ovek/understanding_when_to_use_jpa_vs_hibernate/

Shrub

Good history part. while other answers are just repeating what is in the question. – Vitality

Thanks for thoses enlightening precisions. You said JPA was done because applications where tighly coupled with Hibernate, it was a need for abstraction, ok. But isn't it an infinite problem ? Isn't the application now tighly coupled to JPA instead ? What is the real benefit in here ? I already see Hibernate as an abstraction Layer... – Berkelium

@Berkelium Sure, and when you code .java files you are also tightly coupled to Java, so what if I want to switch to Python tomorrow? – Charmer

Answer 4

JPA is the interface while Hibernate is the implementation.

Traditionally there have been multiple Java ORM solutions:

• Hibernate
• TopLink
• JDO

each implementation defining its own mapping definition or client API. The JPA expert group gathered the best of all these tools and so they created the Java Persistence API standard.

A standard persistence API is very convenient from a client point of view, making it relatively easy to switch one implementation with the other (although in practice it's not that simple because on large projects you'll have to use specific non-standard features anyway).

The standard JPA has pushed Java ORM competition to a new level and this can only lead to better implementations.

As explained in my book, High-Performance Java Persistence, Hibernate offers features that are not yet supported by JPA:

• extended identifier generators (hi/lo, pooled, pooled-lo)
• transparent prepared statement batching
• customizable CRUD (@SQLInsert, @SQLUpdate, @SQLDelete) statements
• static or dynamic collection filters (e.g. @FilterDef, @Filter, @Where) and entity filters (e.g. @Where)
• mapping properties to SQL fragments (e.g. @Formula)
• immutable entities (e.g. @Immutable)
• more flush modes (e.g. FlushMode.MANUAL, FlushMode.ALWAYS)
• querying the second-level cache by the natural key of a given entity
• entity-level cache concurrency strategies (e.g. Cache(usage = CacheConcurrencyStrategy.READ_WRITE))
• versioned bulk updates through HQL
• exclude fields from optimistic locking check (e.g. @OptimisticLock(excluded = true))
• versionless optimistic locking (e.g. OptimisticLockType.ALL, OptimisticLockType.DIRTY)
• support for skipping (without waiting) pessimistic lock requests
• support for Java 8 Date and Time
• support for multitenancy
• support for soft delete (e.g. @Where, @Filter)

These extra features allow Hibernate to address many persistence requirements demanded by large enterprise applications.

Malindamalinde

This is good one, I did not know about other ORM tools earlier – Flaunch

Great answer and I am enjoying the book tremendously! Thanks for releasing it! – Rountree

Thanks for enjoying my High-Performance Java Persistence book. – Malindamalinde

This ~ JPA is the interface while Hibernate is the implementation – Susceptible

Answer 5

From the Wiki.

Motivation for creating the Java Persistence API

Many enterprise Java developers use lightweight persistent objects provided by open-source frameworks or Data Access Objects instead of entity beans: entity beans and enterprise beans had a reputation of being too heavyweight and complicated, and one could only use them in Java EE application servers. Many of the features of the third-party persistence frameworks were incorporated into the Java Persistence API, and as of 2006 projects like Hibernate (version 3.2) and Open-Source Version TopLink Essentials have become implementations of the Java Persistence API.

As told in the JCP page the Eclipse link is the Reference Implementation for JPA. Have look at this answer for bit more on this.

JPA itself has features that will make up for a standard ORM framework. Since JPA is a part of Java EE spec, you can use JPA alone in a project and it should work with any Java EE compatible Servers. Yes, these servers will have the implementations for the JPA spec.

Hibernate is the most popular ORM framework, once the JPA got introduced hibernate conforms to the JPA specifications. Apart from the basic set of specification that it should follow hibernate provides whole lot of additional stuff.

Wera

That said you can use JPA alone in a project.?? Do you mean without using Hibernate, TopLink or any other JPA implementation? – Geoffreygeoffry

@Geoffreygeoffry yes. The Java EE specs only uses JPA. If you add hibernate, it give some additional features. – Wera

I heard JPA is only an interface/specification. If we use JPA alone in a project then where from it gets its implementation? – Geoffreygeoffry

@Geoffreygeoffry thank for the comment. I have added more details in the answer. Hope this helps. – Wera

I got same question like @Abbas ..i am confuse , – Soni

@Forhad There always needs to be an implementation, whether its buried in some server architecture or not doesn't matter, there is no way to just download some JPA library and have it perform persistence for you. – Firing

Part that says that you can you JPA alone it is still confusing. – Corker

Answer 6

JPA is just a specification which needs concrete implementation. The default implementation oracle provide is "Eclipselink" now. (Toplink is donated by Oracle to Eclipse foundation to merge with eclipselink)

(Reference : http://www.oracle.com/technetwork/middleware/toplink/index-085257.html http://www.eclipse.org/org/press-release/20080317_Eclipselink.php )

Using Eclipselink, one can be sure that the code is portable to any implementation if need arises. Hibernate is also a full JPA implementation + MORE ( Sort of JPA Plus). Hibernate is super set of JPA with some extra Hibernate specific functionality. So app developed in Hibernate may not be compatible when switched to other implementation. Still hibernate is choice of majority of developers as JPA implementation and widely used.

Another JPA implementation is OpenJPA (openjpa.apache.org) which is an extension of Kodo implementation.

Mourner

Answer 7

JPA : is just like an interface and have no concrete implementation of it to use functions which are there in JPA.

Hibernate : is just a JPA Provider which have the implementation of the functions in JPA and can have some extra functions which might not be there in JPA.

TIP : you can use

     *combo 1* : JPA + JPA Provider(Hibernate) 
     *combo 2* : only Hiberante which does not need any interface 

Combo 1 : is used when you feel that your hibernate is not giving better performance and want to change JPA Provider that time you don't have to write your JPA once again. You can write another JPA Provider ... and can change as many times you can.

Combo 2 : is used very less as when you are not going change your JPA Provider at any cost.

Visit http://blog-tothought.rhcloud.com//post/2, where your complete confusion will get clear.

Garnishment

Answer 8

JPA is the interface, Hibernate is one implementation of that interface.

Arlon

and on top of that Hibernate adds some more features/methods. – Pumphrey

Answer 9

JPA is a specification to standardize ORM-APIs. Hibernate is a vendor of a JPA implementation. So if you use JPA with hibernate, you can use the standard JPA API, hibernate will be under the hood, offering some more non standard functions. See http://docs.jboss.org/hibernate/stable/entitymanager/reference/en/html_single/ and http://docs.jboss.org/hibernate/stable/annotations/reference/en/html_single/

Bushelman

Answer 10

JPA is just a specification.In market there are many vendors which implements JPA. Different types of vendors implement JPA in different way. so different types of vendors provide different functionality so choose proper vendor based on your requirements.

If you are using Hibernate or any other vendors instead of JPA than you can not easily move to hibernate to EclipseLink or OpenJPA to Hibernate.But If you using JPA than you just have to change provide in persistence XML file.So migration is easily possible in JPA.

Reld

Answer 11

JPA is an API, one which Hibernate implements.Hibernate predates JPA. Before JPA, you write native hibernate code to do your ORM. JPA is just the interface, so now you write JPA code and you need to find an implementation. Hibernate happens to be an implementation.

So your choices are this: hibernate, toplink, etc...

The advantage to JPA is that it allows you to swap out your implementation if need be. The disadvantage is that the native hibernate/toplink/etc... API may offer functionality that the JPA specification doesn't support.

Presocratic

Answer 12

While JPA is the specification, Hibernate is the implementation provider that follows the rules dictated in the specification.

Charin

Answer 13

Java - its independence is not only from the operating system, but also from the vendor.

Therefore, you should be able to deploy your application on different application servers. JPA is implemented in any Java EE- compliant application server and it allows to swap application servers, but then the implementation is also changing. A Hibernate application may be easier to deploy on a different application server.

Cochineal

Answer 14

JPA is a specification that you implement in your data layer to perform db opertations, OR mappings and other required tasks.

Since it is just a specification, you need a tool to have it implemented. That tool can be either Hibernate, TopLink, iBatis, spring-data etc.

You don't necessarily require JPA if you are using Hibernate in your Data Layer. But if you use JPA specification for Hibernate, then it will make switching to other ORM tools like iBatis, TopLink easy in future, because the specification is common for others as well.

*(if you remember, you do import javax.persistence.*; when you use annotations for OR mapping (like @Id, @Column, @GeneratedValue etc.) in Hibernate, that's where you are using JPA under Hibernate, you can use JPA's @Query & other features as well)

Curch

Answer 15

JPA is a Java API specification which describes the management of relational data in applications using Java Platform. where as Hibernate is a ORM (Object Relational Mapping) library which follows JPA specification.

You can think JPA as a set of Rules which is implemented by Hibernate.

Baier

Answer 16

JPA is JSR i.e. Java Specification Requirement to implement Object Relational Mapping which has got no specific code for its implementation. It defines certain set of rules for for accessing, persisting and managing the data between Java objects and the relational databaseWith its introduction, EJB was replaced as It was criticized for being heavyweight by the Java developer community. Hibernate is one of the way JPA can be implemented using te guidelines.Hibernate is a high-performance Object/Relational persistence and query service which is licensed under the open source GNU Lesser General Public License (LGPL) .The benefit of this is that you can swap out Hibernate's implementation of JPA for another implementation of the JPA specification. When you use straight Hibernate you are locking into the implementation because other ORMs may use different methods/configurations and annotations, therefore you cannot just switch over to another ORM.

Candra

Answer 17

JPA is just a specification which needs concrete implementation. The default implementation provided by oracle is "Eclipselink" now. Toplink is donated by Oracle to Eclipse foundation to merge with eclipselink.

Using Eclipselink, one can be sure that the code is portable to any implementation if need arises. Hibernate is also a full JPA implementation + MORE. Hibernate is super set of JPA with some extra Hibernate specific functionality. So application developed in Hibernate may not be compatible when switched to other implementation. Still hibernate is choice of majority of developers as JPA implementation and widely used.

Another JPA implementation is OpenJPA, which is an extension of Kodo implementation.

JPA vs Hibernate

Bilberry

Answer 18

I try to explain in very easy words.

Suppose you need a car as we all know their are several A class manufacturer like MERCEDES, BMW , AUDI etc.

Now in above statement CAR(is a specification) as every car have common features like thing with 4 wheels and can be driven on road is car...so its like JPA. And MERCEDES, BMW , AUDI etc are just using common car feature and adding functionality according to their customer base so they are implementing the car specification like hibernate , iBATIS etc.

So by this common features goes to jpa and hibernate is just an implementation according to their jboss need.

1 more thing

JPA includes some basic properties so in future if you want to change hibernate to any other implementation you can easily switch without much headache and for those basic properties includes JPA annotations which can work for any implementation technology, JPQL queries.

So mainly we implement hibernate with JPA type technology just for in case we want to switch our implementation according to client need plus you will write less code as some common features are involved in JPA. If someone still not clear then you can comment as i m new on stack overflow.

Thank you

Colophony

Answer 19

JPA is just a specification while Hibernate is one of the JPA provider i.e hibernate is implementing various things mentioned in JPA contract.

Alimony

Answer 20

JPA or Java Persistence API is a standard specification for ORM implementations whereas Hibernate is the actual ORM implementation or framework.

Nolen

Answer 21

JPA is Java Persistence API. Which Specifies only the specifications for APIs. Means that the set of rules and guidelines for creating the APIs. If says another context, It is set of standards which provides the wrapper for creating those APIs , can be use for accessing entity object from database. JPA is provided by oracle.When we are going to do database access , we definitely needs its implementation. Means JPA specifies only guidelines for implementing APIs. Hibernate is a JPA provider/Vendor who responsible for implementing that APIs. Like Hibernate TopLink and Open JPA is some of examples of JPA API providers. So we uses JPA specified standard APIs through hibernate.

Rapp

Answer 22

Figuratively speaking JPA is just interface, Hibernate/TopLink - class (i.e. interface implementation).

You must have interface implementation to use interface. But you can use class through interface, i.e. Use Hibernate through JPA API or you can use implementation directly, i.e. use Hibernate directly, not through pure JPA API.

Good book about JPA is "High-Performance Java Persistence" of Vlad Mihalcea.

Caernarvonshire