UWECProgrammer/ConsolidatedMentionResolutionBenchmark

sentence stringlengths 1 1.38k	label stringclasses 3 values
However Jboss picketbox gives you a really easy way to go, unless you need something specific.	o
I can't speak too much to JAAS itself, but this URL_http://static.springsource.org/spring-security/site/start-here.html ["suggested-steps"-guide] on Spring Security and URL_http://static.springframework.org/spring-security/site/reference.html [the-reference-manual] are both pretty good resources on Spring Security - if your setup is anything close to simple, you don't really need to do much more than read these.	p
The "suggested steps" guide has moved here: URL_http://static.springsource.org /spring-security/site/start-here.html.	o
thanks, updated the link.	o
For a purely JAAS tutorial check out URL_http://www.javaworld.com/javaworld/jw-09-2002/jw-0913-jaas.html [this] .	o
It's old but should help with the JAAS basics.	o
lsiu's answer is one the few answers here that really "get it" ;) Adding to that answer, a really good reference on this topic is URL_http://java.sys-con.com/node/1002315 [Whatever-Happened-to-JAAS?	o
] .	o
It explains how JASPIC is the link in Java EE between the Servlet and EJB security models and potentially a JAAS login module, but that in many cases JAAS' role is reduced to that of a relatively simple username and roles provider in Java EE.	p
From the same author is URL_http://raymondkng.sys-con.com/node/171477 [JAAS- in-the-Enterprise] , which is an older article but provides a lot of historical background on why the Java SE (JAAS) and Java EE models diverged the way they did.	o
Overall but a few types from JAAS are directly used in Java EE, basically CODETERM1 , CODETERM2 , and CODETERM3 .	o
The latter two are mainly used by JASPIC.	o
I've explained JASPIC in the article URL_http://arjan- tijms.blogspot.com/2012/11/implementing-container-authentication.html [Implementing-container-authentication-in-Java-EE-with-JASPIC] .	o
What's the best way to share business object instances between Java web apps using JBoss and Spring?	o
We currently have a web application loading a Spring application context which instantiates a stack of business objects, DAO objects and Hibernate.	o
We would like to share this stack with another web application, to avoid having multiple instances of the same objects.	o
We have looked into several approaches; exposing the objects using JMX or JNDI, or using EJB3.	o
The different approaches all have their issues, and we are looking for a lightweight method.	p
Any suggestions on how to solve this?	o
Edit: I have received comments requesting me to elaborate a bit, so here goes: The main problem we want to solve is that we want to have only one instance of Hibernate.	o
This is due to problems with invalidation of Hibernate's 2nd level cache when running several client applications working with the same datasource.	p
Also, the business/DAO/Hibernate stack is growing rather large, so not duplicating it just makes more sense.	o
First, we tried to look at how the business layer alone could be exposed to other web apps, and Spring offers JMX wrapping at the price of a tiny amount of XML.	o
However, we were unable to bind the JMX entities to the JNDI tree, so we couldn't lookup the objects from the web apps.	o
Then we tried binding the business layer directly to JNDI.	o
Although Spring didn't offer any method for this, using JNDITemplate to bind them was also trivial.	n
But this led to several new problems: 1) Security manager denies access to RMI classloader, so the client failed once we tried to invoke methods on the JNDI resource.	n
2) Once the security issues were resolved, JBoss threw IllegalArgumentException: object is not an instance of declaring class.	o
A bit of reading reveals that we need stub implementations for the JNDI resources, but this seems like a lot of hassle (perhaps Spring can help us?	o
) We haven't looked too much into EJB yet, but after the first two tries I'm wondering if what we're trying to achieve is at all possible.	o
To sum up what we're trying to achieve: One JBoss instance, several web apps utilizing one stack of business objects on top of DAO layer and Hibernate.	o
Best regards, Nils .	p
Could you comment on 1.	o
What problem you're trying to solve; 2.	o
The issues you found with the respective approaches you mention.	o
This would allow a more focused answer...	p
It was difficult to say it all in 300 characters, so I edited the question to add more details :-).	n
Are the web applications deployed on the same server?	o
I can't speak for Spring, but it is straightforward to move your business logic in to the EJB tier using Session Beans.	p
The application organization is straight forward.	o
The Logic goes in to Session Beans, and these Session Beans are bundled within a single jar as an Java EE artifact with a ejb-jar.xml file (in EJB3, this will likely be practically empty).	o
Then bundle you Entity classes in to a seperate jar file.	o
Next, you will build each web app in to their own WAR file.	o
Finally, all of the jars and the wars are bundled in to a Java EE EAR, with the associated application.xml file (again, this will likely be quite minimal, simply enumerating the jars in the EAR).	o
This EAR is deployed wholesale to the app server.	o
Each WAR is effectively independent -- their own sessions, there own context paths, etc.	o
But they share the common EJB back end, so you have only a single 2nd level cache.	o
You also use local references and calling semantic to talk to the EJBs since they're in the same server.	o
No need for remote calls here.	o
I think this solves quite well the issue you're having, and its is quite straightforward in Java EE 5 with EJB 3.	p
Also, you can still use Spring for much of your work, as I understand, but I'm not a Spring person so I can not speak to the details.	o
Yes, everything is deployed to the same server.	o
This looks quite interesting, I'll give EJB a shot today.	p
My point about Spring is that it offers to wrap beans for e.g.	o
JMX without any code, but apparently not for EJB.	o
Anyway, I look at the EJB approach today.	o
What about spring parentContext?Check out this article: URL_http://springtips.blogspot.com/2007/06/using-shared-parent-application- context.html [ URL_http://springtips.blogspot.com/2007/06/using-shared-parent - application-context.html] .	o
URL_http://www.terracotta.org/ [Terracotta] might be a good fit here (disclosure: I am a developer for Terracotta).	p
Terracotta transparently clusters Java objects at the JVM level, and integrates with both Spring and Hibernate.	o
It is free and open source.	p
As you said, the problem of more than one client web app using an L2 cache is keeping those caches in synch.	o
With Terracotta you can cluster a single Hibernate L2 cache.	o
Each client node works with it's copy of that clustered cache, and Terracotta keeps it in synch.	p
URL_http://www.terracotta.org/web/display/orgsite/Hibernate+Integration [This-link] explains more.	o
As for your business objects, you can use Terracotta's URL_http://www.terracotta.org/web/display/orgsite/Spring+Integration [Spring- integration] to cluster your beans - each web app can share clustered bean instances, and Terracotta keeps the clustered state in synch transparently.	o
You should take a look at the Terracotta Reference Web Application - Examinator.	o
It has most of the components you are looking for - it's got Hibernate, JPA, and Spring with a MySQL backend.	o
It's been pre-tuned to scale up to 16 nodes, 20k concurrent users.	o
Check it out here: URL_http://reference.terracotta.org/examinator [ URL_http://reference.terracotta.org/examinator ] .	o
Actually, if you want a lightweight solution and don't need transactions or clustering just use Spring support for RMI.	p
It allows to expose Spring beans remotely using simple annotations in the latest versions.	p
See URL_http://stati c.springframework.org/spring/docs/2.0.x/reference/remoting.html [ URL_http://static.springframework.org/spring/docs/2.0.x/reference/remoting.html ] .	o
I have used this approach to access shared Spring beans from a webapp.	o
It works though I still feel there is probably a better/cleaner solution.	p
If you don't like RMI, Spring offers a few other remoting options - Hessian, Burlap, and HttpInvoker (Spring's custom remoting solution - Java serialization over HTTP).	o
Of course there are always web services as well.	p
Spring does have an integration point that might be of interest to you: URL_http://static.springframework.org/spring/docs/2.5.x/reference/ejb.html [EJB-3-injection-nterceptor] .	o
This enables you to access spring beans from EJBs.	o
Thank you for your answers so far.	p
We're still not quite there, but we have tried a few things now and see things more clearly.	o
Here's a short update: The solution which appears to be the most viable is EJB.	o
However, this will require some amount of changes in our code, so we're not going to fully implement that solution right now.	o
I'm almost surprised that we haven't been able to find some Spring feature to help us out here.	o
We have also tried the JNDI route, which ends with the need for stubs for all shared interfaces.	o
This feels like a lot of hassle, considering that everything is on the same server anyway.	o
Yesterday, we had a small break through with JMX.	o
Although JMX is definately not meant for this kind of use, we have proven that it can be done - with no code changes and a minimal amount of XML (a big Thank You to Spring for MBeanExporter and MBeanProxyFactoryBean).	p
The major drawbacks to this method are performance and the fact that our domain classes must be shared through JBoss' server/lib folder.	o
I.e., we have to remove some dependencies from our WARs and move them to server/lib, else we get ClassCastException when the business layer returns objects from our own domain model.	o
I fully understand why this happens, but it is not ideal for what we're trying to achieve.	n
I thought it was time for a little update, because what appears to be the best solution will take some time to implement.	n
I'll post our findings here once we've done that job.	o
It's been suggested several times on this thread by myself and others, but have you looked at Terracotta?	o
Unlike all the other solutions presented thus far, it is designed explicitly for state sharing which is what you asked for.	o
I'm not really sure what you are trying to solve; at the end of the day each jvm will either have replicated instances of the objects, or stubs representing objects existing on another (logical) server.	o
You could, setup a third 'business logic' server that has a remote api which your two web apps could call.	o
The typical solution is to use EJB, but I think spring has remoting options built into its stack.	o
The other option is to use some form of shared cache architecture... which will synchronize object changes between the servers, but you still have two sets of instances.	o
Not so if you use Terracotta.	o
Take a look at URL_http://www.jboss.org/jbosscache/ [JBossCache] .	o

However Jboss picketbox gives you a really easy way to go, unless you need something specific.

o

I can't speak too much to JAAS itself, but this URL_http://static.springsource.org/spring-security/site/start-here.html ["suggested-steps"-guide] on Spring Security and URL_http://static.springframework.org/spring-security/site/reference.html [the-reference-manual] are both pretty good resources on Spring Security - if your setup is anything close to simple, you don't really need to do much more than read these.

p

The "suggested steps" guide has moved here: URL_http://static.springsource.org /spring-security/site/start-here.html.

o

thanks, updated the link.

o

For a purely JAAS tutorial check out URL_http://www.javaworld.com/javaworld/jw-09-2002/jw-0913-jaas.html [this] .

o

It's old but should help with the JAAS basics.

o

lsiu's answer is one the few answers here that really "get it" ;) Adding to that answer, a really good reference on this topic is URL_http://java.sys-con.com/node/1002315 [Whatever-Happened-to-JAAS?

o

] .

o

It explains how JASPIC is the link in Java EE between the Servlet and EJB security models and potentially a JAAS login module, but that in many cases JAAS' role is reduced to that of a relatively simple username and roles provider in Java EE.

p

From the same author is URL_http://raymondkng.sys-con.com/node/171477 [JAAS- in-the-Enterprise] , which is an older article but provides a lot of historical background on why the Java SE (JAAS) and Java EE models diverged the way they did.

o

Overall but a few types from JAAS are directly used in Java EE, basically CODETERM1 , CODETERM2 , and CODETERM3 .

o

The latter two are mainly used by JASPIC.

o

I've explained JASPIC in the article URL_http://arjan- tijms.blogspot.com/2012/11/implementing-container-authentication.html [Implementing-container-authentication-in-Java-EE-with-JASPIC] .

o

What's the best way to share business object instances between Java web apps using JBoss and Spring?

o

We currently have a web application loading a Spring application context which instantiates a stack of business objects, DAO objects and Hibernate.

o

We would like to share this stack with another web application, to avoid having multiple instances of the same objects.

o

We have looked into several approaches; exposing the objects using JMX or JNDI, or using EJB3.

o

The different approaches all have their issues, and we are looking for a lightweight method.

p

Any suggestions on how to solve this?

o

Edit: I have received comments requesting me to elaborate a bit, so here goes: The main problem we want to solve is that we want to have only one instance of Hibernate.

o

This is due to problems with invalidation of Hibernate's 2nd level cache when running several client applications working with the same datasource.

p

Also, the business/DAO/Hibernate stack is growing rather large, so not duplicating it just makes more sense.

o

First, we tried to look at how the business layer alone could be exposed to other web apps, and Spring offers JMX wrapping at the price of a tiny amount of XML.

o

However, we were unable to bind the JMX entities to the JNDI tree, so we couldn't lookup the objects from the web apps.

o

Then we tried binding the business layer directly to JNDI.

o

Although Spring didn't offer any method for this, using JNDITemplate to bind them was also trivial.

n

But this led to several new problems: 1) Security manager denies access to RMI classloader, so the client failed once we tried to invoke methods on the JNDI resource.

n

2) Once the security issues were resolved, JBoss threw IllegalArgumentException: object is not an instance of declaring class.

o

A bit of reading reveals that we need stub implementations for the JNDI resources, but this seems like a lot of hassle (perhaps Spring can help us?

o

) We haven't looked too much into EJB yet, but after the first two tries I'm wondering if what we're trying to achieve is at all possible.

o

To sum up what we're trying to achieve: One JBoss instance, several web apps utilizing one stack of business objects on top of DAO layer and Hibernate.

o

Best regards, Nils .

p

Could you comment on 1.

o

What problem you're trying to solve; 2.

o

The issues you found with the respective approaches you mention.

o

This would allow a more focused answer...

p

It was difficult to say it all in 300 characters, so I edited the question to add more details :-).

n

Are the web applications deployed on the same server?

o

I can't speak for Spring, but it is straightforward to move your business logic in to the EJB tier using Session Beans.

p

The application organization is straight forward.

o

The Logic goes in to Session Beans, and these Session Beans are bundled within a single jar as an Java EE artifact with a ejb-jar.xml file (in EJB3, this will likely be practically empty).

o

Then bundle you Entity classes in to a seperate jar file.

o

Next, you will build each web app in to their own WAR file.

o

Finally, all of the jars and the wars are bundled in to a Java EE EAR, with the associated application.xml file (again, this will likely be quite minimal, simply enumerating the jars in the EAR).

o

This EAR is deployed wholesale to the app server.

o

Each WAR is effectively independent -- their own sessions, there own context paths, etc.

o

But they share the common EJB back end, so you have only a single 2nd level cache.

o

You also use local references and calling semantic to talk to the EJBs since they're in the same server.

o

No need for remote calls here.

o

I think this solves quite well the issue you're having, and its is quite straightforward in Java EE 5 with EJB 3.

p

Also, you can still use Spring for much of your work, as I understand, but I'm not a Spring person so I can not speak to the details.

o

Yes, everything is deployed to the same server.

o

This looks quite interesting, I'll give EJB a shot today.

p

My point about Spring is that it offers to wrap beans for e.g.

o

JMX without any code, but apparently not for EJB.

o

Anyway, I look at the EJB approach today.

o

What about spring parentContext?Check out this article: URL_http://springtips.blogspot.com/2007/06/using-shared-parent-application- context.html [ URL_http://springtips.blogspot.com/2007/06/using-shared-parent - application-context.html] .

o

URL_http://www.terracotta.org/ [Terracotta] might be a good fit here (disclosure: I am a developer for Terracotta).

p

Terracotta transparently clusters Java objects at the JVM level, and integrates with both Spring and Hibernate.

o

It is free and open source.

p

As you said, the problem of more than one client web app using an L2 cache is keeping those caches in synch.

o

With Terracotta you can cluster a single Hibernate L2 cache.

o

Each client node works with it's copy of that clustered cache, and Terracotta keeps it in synch.

p

URL_http://www.terracotta.org/web/display/orgsite/Hibernate+Integration [This-link] explains more.

o

As for your business objects, you can use Terracotta's URL_http://www.terracotta.org/web/display/orgsite/Spring+Integration [Spring- integration] to cluster your beans - each web app can share clustered bean instances, and Terracotta keeps the clustered state in synch transparently.

o

You should take a look at the Terracotta Reference Web Application - Examinator.

o

It has most of the components you are looking for - it's got Hibernate, JPA, and Spring with a MySQL backend.

o

It's been pre-tuned to scale up to 16 nodes, 20k concurrent users.

o

Check it out here: URL_http://reference.terracotta.org/examinator [ URL_http://reference.terracotta.org/examinator ] .

o

Actually, if you want a lightweight solution and don't need transactions or clustering just use Spring support for RMI.

p

It allows to expose Spring beans remotely using simple annotations in the latest versions.

p

See URL_http://stati c.springframework.org/spring/docs/2.0.x/reference/remoting.html [ URL_http://static.springframework.org/spring/docs/2.0.x/reference/remoting.html ] .

o

I have used this approach to access shared Spring beans from a webapp.

o

It works though I still feel there is probably a better/cleaner solution.

p

If you don't like RMI, Spring offers a few other remoting options - Hessian, Burlap, and HttpInvoker (Spring's custom remoting solution - Java serialization over HTTP).

o

Of course there are always web services as well.

p

Spring does have an integration point that might be of interest to you: URL_http://static.springframework.org/spring/docs/2.5.x/reference/ejb.html [EJB-3-injection-nterceptor] .

o

This enables you to access spring beans from EJBs.

o

Thank you for your answers so far.

p

We're still not quite there, but we have tried a few things now and see things more clearly.

o

Here's a short update: The solution which appears to be the most viable is EJB.

o

However, this will require some amount of changes in our code, so we're not going to fully implement that solution right now.

o

I'm almost surprised that we haven't been able to find some Spring feature to help us out here.

o

We have also tried the JNDI route, which ends with the need for stubs for all shared interfaces.

o

This feels like a lot of hassle, considering that everything is on the same server anyway.

o

Yesterday, we had a small break through with JMX.

o

Although JMX is definately not meant for this kind of use, we have proven that it can be done - with no code changes and a minimal amount of XML (a big Thank You to Spring for MBeanExporter and MBeanProxyFactoryBean).

p

The major drawbacks to this method are performance and the fact that our domain classes must be shared through JBoss' server/lib folder.

o

I.e., we have to remove some dependencies from our WARs and move them to server/lib, else we get ClassCastException when the business layer returns objects from our own domain model.

o

I fully understand why this happens, but it is not ideal for what we're trying to achieve.

n

I thought it was time for a little update, because what appears to be the best solution will take some time to implement.

n

I'll post our findings here once we've done that job.

o

It's been suggested several times on this thread by myself and others, but have you looked at Terracotta?

o

Unlike all the other solutions presented thus far, it is designed explicitly for state sharing which is what you asked for.

o

I'm not really sure what you are trying to solve; at the end of the day each jvm will either have replicated instances of the objects, or stubs representing objects existing on another (logical) server.

o

You could, setup a third 'business logic' server that has a remote api which your two web apps could call.

o

The typical solution is to use EJB, but I think spring has remoting options built into its stack.

o

The other option is to use some form of shared cache architecture... which will synchronize object changes between the servers, but you still have two sets of instances.

o

Not so if you use Terracotta.

o

Take a look at URL_http://www.jboss.org/jbosscache/ [JBossCache] .

o