I'd like to use JPA along with Bean Validation, so JPA 2.0 sounds like what I need. I'm running my web application on Tomcat 6. Is Tomcat able to use JPA2?
Yes. You just need to place a JPA implementation (Hibernate, EclipseLink, etc) in WEB-INF/lib
Related
I am using JPA 2.1 in my project (Hibernate 5.x) and deploying in IBM WAS 8.5.5.
Since IBM WAS 8.5.5 supports only JPA 2.0 by the container, There is persistence loader issue during application deployment.
Is it possible to configure custom JPA at app level in WAS.
I already tried - IBM WAS Documentation
You said you tried https://developer.ibm.com/wasdev/docs/can-i-use-jpa-2-1-on-websphere-application-server/, but what part of this document is not working? This is the page I would reference if you are trying to get JPA 2.1 running on 8.5.5.
Some alternate suggestions:
Traditional WebSphere v9 supports the JPA 2.1 specification level. I would recommend using WebSphere v9 for your project instead of 8.5.5 if you really need to use Hibernate 5.x
Hibernate 4.2 was the last version that supports JPA 2.0. You can downgrade to this version of Hibernate if you dont have to use JPA 2.1
Either of these solutions gain you container support and will provide the JPA API bundle for you. Whichever you go with, make sure not to bundle your Hibernate JPA persistence API bundles in your application. Hibernate repackages its API into "hibernate-jpa-2.x-api.Final.jar". I have seen this before as a conflict that customers build into their applications.
With class loading strategy, I was able to override the JPA 2.0 of container.
using the inputs from IBM Developers support.
I have some confusion on using JTA within the Spring Framework on Apache Tomcat and i hope someone will clarify as after many research i can't seem to find the correct answer as of yet.
I am developing a web application using Spring Framework to be running on Apache Tomcat 6.
I read somewhere that Spring's does support for JTA but it delegates to the underlying JavaEE application server. Now this is where i am confused because i Tomcat is not a full JavaEE application server - it is merely a servlet container and as i believe it doesn't provide JTA implementation like the full JavaEE application server (Glassfish/Wildfly etc...) does.
But when i do something like the following the transaction aspect of it works:
#Transactional
public class ServiceClassImpl implements ServiceInterface {
// code here that involves transactions e.g. calling DAO code
...
}
So, i'm confused. I hope someone will enlighten me.
The answer is: NO.
Tomcat 6.x (7&8) don't provide JTA out-of-the-box because they don't have a transaction manager which is required as a separate component to monitor multiple resources (e.g. datasources).
The mentioned answer How to use JTA support in Tomcat 6 for Hibernate? already gives a list of additional JTA transaction managers that can be used alongside Tomcat.
Spring supports declarative transaction management via a platform transaction manager (TM) and provides some implementations (e.g. datasources) that make #Transactional work on a single resource without the additional TM.
Understanding the Spring Framework transaction abstraction provides more details and Spring Boot can be easily configured to run Atomikos or Bitronix Transaction managers on the embedded Tomcat.
JTA provides you with distributed transactions support, but if JTA is not available like in Tomcat, you still can use local JDBC transactions.
YES :-)
JTA can be used in Tomcat, for instance via https://www.atomikos.com
The trick is to use a componentized JTA implementation.
Cheers
i am reading book about EJB 3.l, and they are talking about Enities and EntityManager, but i cant see any Hibernate(or other ORM framework) configuration. Does EJB has its own ORM and JPA support ?
EJB and JPA are two different specifications that are part of the Java EE standard. You can use either of them without using the other.
EDIT: EJB is used within Java EE compliant servers like WildFly (formerly known as JBoss) and Glassfish. IF you are using one, you always have an implementation of JPA on board.
JPA on the other hand is not bound to such a server and can be used in servlet containers like Tomcat and standalone Java SE applications.
JPA can be used outside the container like with RESTful WS. While EJB resides in containers like WebLogic, Tomcat, etc.
In a way, JPA is a lighter version of EJB. Try googling JPA vs EJB3
I have use JPA with Hibernate in a standalone application but now I want to try with with an application server. I know GlassFish provides EclipseLink implementation for JPA but I have a few questions.
Do I need to specify in persistence.xml EclipseLink as a provider for my persistence-unit?
Does persistence.xml look the same as if it the application would not be deployed? If it does not look the same how does it look?
Do I need to specifically download the implementation jars for EclipseLink and build with them or does the container handles this after my application is deployed?
How do I specify the jdbc driver in persistence.xml?
Does my application need to be deployed as a .ear?
You don't need to specify the persistence provider, by default the one contained in your application server will be used (if it has at least the Web profile, of course, otherwise servers such as Tomcat won't provide you EclipseLink).
Yes, it will have the same look (in both applications you are just using JPA the same way).
For your code to compile, you will only need to have persistence-api.jar in your classpath (if you use Maven, set the scope to "provided"). Then the server will automatically provide its implementation jars.
You could use a persistence unit like described in this page ("typical configuration in a Java SE environment"). But I would rather suggest you use a <jta-data-source> instead, that refers to a datasource provided by GlassFish.
As far as I can tell, it can also be a WAR file, I didn't have any problem deploying it (webapp as a Maven WAR module + beans in a JAR module).
I have a 100% JPA2 compliant application which needs to be portable to many application servers. Being JPA compliant (theoretically) means we can switch JPA providers via configuration (e.g. without changing source code) -- (right???).
When running within a servlet container (e.g. Tomcat, Jetty) the application is configured to run with Hibernate. We choose Hibernate over TopLink and Eclipselink for its maturity and performance. So far this works.
However, when running within a Java EE application server, should we default to the JPA provider therein, or stick with Hibernate?
I know within JBoss, the provider is Hibernate so it probably doesn't matter. However, I think the provider within WebLogic is Eclipselink. I have no idea what the provider WebSphere or Glassfish use, but I have seen detailed instructions on how to use Hibernate as the provider within those application servers.
I guess another way to ask the question is what would we be missing by using Hibernate in these application servers?
I have a 100% JPA2 compliant application which needs to be portable to many application servers. Being JPA compliant (...) means we can switch JPA providers via configuration (...)
Yes.
(...) However, when running within a Java EE application server, should we default to the JPA provider therein, or stick with Hibernate?
Well, if you deploy on a Java EE 6 server, this doesn't really matter. It's not clear who is going to run the application and you can maybe make recommendations but the runtime is actually "not your business" :) Also note that you may not benefit from support if you don't use the default provider (if this matters).
I know within JBoss, the provider is Hibernate so it probably doesn't matter. However, I think the provider within WebLogic is Eclipselink. I have no idea what the provider WebSphere or Glassfish use, but I have seen detailed instructions on how to use Hibernate as the provider within those application servers.
First of all, keep in mind that JPA 2.0 is part of Java EE 6 and that GlassFish v3 is the only one Java EE 6 container at this time. WebLogic and WebSphere are Java EE 5 server, they may not support JPA 2.0.
Now, regarding the default providers:
GlassFish v3 uses EclipseLink 2.0 as default provider but can be configured to use Hibernate 3.5 (through an add-on).
In Weblogic 10.3.2, the default JPA provider is OpenJPA/Kodo and EclipseLink 1.2 is available as a WLS module. In WLS 10.3.3 (not released yet), EclipseLink 2.0 will be available as a WLS module, the default being still OpenJPA/Kodo. But, the container JPA API will still be JPA 1.0! It seems possible to package a JPA 2.0 provider inside your application. See this thread and this page. But this is not officially supported and doing this same thing with Hibernate 3.5 might be another story.
In WebSphere 6 and 7, the default provider is OpenJPA. This link will give you some details about the way to change the default provider (and the consequences). But I can't tell you more.
I guess another way to ask the question is what would we be missing by using Hibernate in these application servers?
As I mentioned, this may not be supported by the vendor. Additionally, if you want to maximize portability and plan to deploy your application in a near future, going for JPA 2.0 is maybe not a wise choice (or too optimistic if you prefer).
I don't see what you will be missing, unless you're using implementation specific API in your JPA code. I.e. do not import org.hibernate anywhere in your JPA code, but just write it against the JPA API.