I'm new to hibernate and don't get the exact meaning of a vendor , vendor implementation ?!
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a recently started this course about spring boot, for a project the mentor used hibernate as JPA vendor
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I would like to know what's the key difference between Apache Open JPA and Spring JPA.
Spring already has a mature JPA for dealing with all kinds of Java persistence but still saw few projects in my company where they uses Apache Open JPA.
Can we integrate Apache Open JPA with Spring. Also like to know what are key benefits of Open JPA.
for example ElasticPath uses Spring but for JPA they uses Apache Open JPA
First: There is no Spring JPA.
There is spring-orm which is one of the many artifacts published by the Spring Framework. It contains classes dealing with JPA and it's main implementations (Hibernate and EclipsLink) in order to integrate them into the rest of the framework. Most Spring users rarely deal with it directly.
You are probably thinking of Spring Data JPA which offers repositories implemented with JPA, which in turn offer many ways to declare queries: Query derivation from method names, named queries based on method names, annotated queries, query by example, specifications ... It is part of the Spring Data project, which offers similar features with many different persistence technologies (JPA, MongoDb, Couchbase, Elasticsearch, Jdbc, Redis, Ldap ...). Spring Data JPA uses spring-orm
Since it got mentioned a couple of times now it is time to explain JPA: JPA stands for Java Persistence API and is an API which can and is implemented by multiple vendors. Hibernate is the most popular implementation, EclipseLink is the reference implementation and Apache Open JPA is another one.
Spring Data JPA (and spring-orm) are (mostly) based on JPA and therefore you should be able to use Apache Open JPA with it. But development of Open JPA was so slow in recent years that the Spring Data Team dropped OpenJPA from the JPA implementations it tests against.
To get a feeling for the development speed, you might look at the releases from the last three years (2019-2021):
Hibernate: 32 (not counting alpha and beta releases)
EclipseLink: 12 (not counting Milestone and release candidates)
OpenJPA: 4
As for the benefits of Apache Open JPA, I consider that an opinion question and therefore off topic for SO. But since people in your company seem to use it, I suggest asking them why they chose Open JPA over the other implementations.
I am working ina Hibernate Search application and I am trying to use version 6 (which right now is in beta). I followed all the instructions and documentation in https://docs.jboss.org/hibernate/search/6.0/reference/en-US/html_single/#getting-started-configuration
After trying to start my application I get next error:
I have looked in Google and seems to be I am the first person in the world who is facing this issue.
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APPLICATION FAILED TO START
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Description:
An attempt was made to call a method that does not exist. The attempt was made from the following location:
org.hibernate.search.mapper.orm.mapping.impl.HibernateOrmIndexedTypeContext.<init>(HibernateOrmIndexedTypeContext.java:35)
The following method did not exist:
org.hibernate.metamodel.spi.MetamodelImplementor.entity(Ljava/lang/Class;)Lorg/hibernate/metamodel/model/domain/spi/EntityTypeDescriptor;
It was loaded from the following location:
file:/home/myUser/.m2/repository/org/hibernate/hibernate-core/5.3.11.Final/hibernate-core-5.3.11.Final.jar
Action:
Correct the classpath of your application so that it contains a single, compatible version of org.hibernate.metamodel.spi.MetamodelImplementor
Any idea of how to solve it?, In my application I am working with Spring boot and jpa.
As indicated here in the documentation, Hibernate Search 6.0.0.Beta2 requires Hibernate ORM 5.4.7.Final or later. You are using Hibernate ORM 5.3.11.Final.
I think Spring Boot 2.1 ships with ORM 5.3, so that's probably what you're using.
The best course of action would be to upgrade to Spring Boot 2.2.1.RELEASE, which ships with Hibernate ORM 5.4.
If that's not possible, you can still stay with Spring Boot 2.1 and override the version of Hibernate ORM directly in your POM: from what I've seen, it works rather well in Spring Boot 2.1.
Just set this property in your POM:
<properties>
<!-- Override the version of Hibernate ORM in Spring Boot -->
<hibernate.version>5.4.7.Final</hibernate.version>
</properties>
Note that technically, any version after Hibernate ORM 5.4.4.Final should work, but sticking to the version Hibernate Search was tested with is usually safer.
Am new to the spring frameworks ,Iam planning to create a Spring Rest application with JPA . am using Mysql database .
I have downloaded the Spring initializer with Web and JPA as dependdencies with Maven. but while Maven install am getting error asking for MYSQL connector jar , so i have adde the maven enetry for the same , on the second try it asking for the hibernate jar .
So am confused like what is the spring-boot-starter-data-jpa dependency doing ? if we need to add the jars into class path , then what is the use of spring-boot-starter-data-jpa ?
spring-boot-starter-data-jpa is a combination of Spring Boot, which itself consists of the Spring framework core and is meant for rapid stand-alone application development, and Spring Data JPA which is Spring's own opinionated abstraction of JPA. It's basically just an interface with a few convenience classes, you still need to supply the JDBC driver for the corresponding database (MySQL in your case) and an actual ORM implementation (the layer that translates your database rows to Java objects and gives you CRUD functionality).
What is the difference between:
persistenc.xml can be configured with hibernate properties OR Javax.persistence properties.
What scenarios would you use either one.
I tried using javax.persistence but my spring app would not work.. changed it to hibernate and it started working.
javax.persistence is the standard. Hibernate is an implementation. If you are completely sure that your DB layer will always be handled by Hibernate, go ahead and configure using Hibernate. If not, use javax.persistence, so that you could change your DB layer in the future.
I’m developing a RCP based app that uses a data access layer implemented using Spring Data JPA backed by hibernate. The annotated domain classes are in one jar/bundle, the Spring repositories and spring config to instantiate the datasource, entity manager, and transaction manager are in another bundle.These jars are used by other non-RCP apps across the project.I have all of the hibernate 3.6.8 jars and dependencies either wrapped and exposed through my own plugins or as OSGI bundles (jta, antlr, commons collections, etc) in the target platform. I’m using Eclipse Gemini Blueprint to manage the bundle spring contexts within the RCP app.
When the DAL bundle spring context is being initialized by the gemini extender, I get Hibernate related ClassDefNotFound exceptions, usually either on org.hibernate.ejb.HibernatePersistence or javax.persistence.spi.Persistenceprovider. I’ve tried putting all of the hibernate jars and dependencies in a single plugin that exports the javax and hibernate packages. I’ve tried setting Eclipse Buddy policies in the manifests of the plugins that I have control over, etc.
I haven’t been able to find any solution to this class loading issue between Spring and Hibernate under Eclipse RCP using Gemini. I’ve done past hibernate DAO projects within RCP by putting all of the hibernate jars in the same plugin as my domain and DAO classes, so only my classes are exported.
At this point I don’t think moving to a more OSGI friendly JPA provider like OpenJPA or EclipseLink is an option.
I found an answer to a slightly related question that suggested putting all of the spring jars and dependencies into a single plugin, with the hibernate jars and dependencies in another plugin with buddy policies set. This seems dirty when most of the jars involved are OSGi bundles.
I suppose I could create a plugin that holds the DAL jar, hibernate jars, and spring ORM jars, so they can all see each other.
Is there a clean way to get this to work?
The core bundle if you own it, add all the suspected bundles as registered buddies and make sure that you have defined packages or bundles are reuired otherwise sometimes buddy class loading is not going to work. If the loading is initiated from you bundle the eclipse buddy policy should cascade. Other option would be to modify the manfiest files in target bundles that are causing issues.