As a seasoned Spring user I was assuming that Spring Integration would make the most sense in a recent project requiring some (JMS) messaging capabilities (more details). After some days working with Spring Integration it still feels like a lot of configuration overhead given the amount of channels you have to configure to bring some request-response (listening on different JMS queues) communications in place.
Therefore I was looking for some background information how Camel is different from Spring Integration, but it seems like information out there are pretty spare, I found:
http://java.dzone.com/articles/spring-integration-and-apache (Very neutral comparison between implementing a real-world integration scenario in Spring Integration vs. Camel, from December 2009)
http://hillert.blogspot.com/2009/10/apache-camel-alternatives.html (Comparing Camel with other solutions, October 2009)
http://raibledesigns.com/rd/entry/taking_apache_camel_for_a (Matt Raible, October 2008)
Question is: what experiences did you make on using the one stack over the other? In which scenarios would you recommend Camel were Spring Integration lacks support? Where do you see pros and cons of each? Any advise from real-world projects are highly appreciated.
We choose Camel over Spring-Integration because the fluent API is really nice. We actually use it in Spring projects and use Spring to configure part of it. The programming API's are clear and there is a large set of sensible components.
We did a small scale shootout and basically at that time for our requirement Camel won. We use it mainly to transfer internal datafiles to/from external parties which usually requires format conversions sending it using ftp/sftp/... or attaching it to an email and sending it out.
We found the edit-compile-debug cycle reduced. Using groovy to experiment setting up routes are added bonuses.
Spring-Integration is a great product too, and I am quite sure it would satisfy our needs too.
I only recommend Spring Integration if you already have got a Spring project and you have just to add some "basic" integration using File, FTP, JMS, JDBC, and so on.
Apache Camel has two main advantages:
Many, many more technologies are supported.
Besides, a (good) XML DSL, there are fluent APIs for Java, Groovy and Scala.
Because Apache Camel has very good integration with Spring, I would even use it instead of Spring Integration in most Spring projects.
If you need more details, you can read my experiences in my blog post: Spoilt for Choice: Which Integration Framework to use – Spring Integration, Mule ESB or Apache Camel?
I have recently conducted a Camel vs Spring Integration shoot-out with the aim to integrate Apache Kafka. Despite being an avid Spring developer, I sadly found my suspicion with Spring's ever-growing Project stack confirmed: Spring is awesome as IOC-Container to serve as glue for other framework, but it fails at providing viable alternatives to those frameworks. There might be exceptions to this, namely everything to do with MVC, where Spring came from and where it does a great job, but other attempts to provide new functionality on top of container features fall short for three reasons and the SI Kafka use case confirms all of them:
Introduction of a long-winded difficult to use DSL for XML-configuration.
Pages of xml-configuration code to get all framework components wired-up.
Missing resources to provide functionality on par with dedicated frameworks.
Now, back to the results of my shoot-out: most importantly I am impressed by Camels overall concept of routes between endpoints. Kafka seamlessly integrates with this concept and three lines of configuration are enough to get everything up-and-running. Problems encountered during the process are neatly addressed by ample documentation from the project team as well as a lot of questions on Stackoverflow. Last but not least, there is a comprehensive integration into Spring that leaves no wishes unfulfilled.
With SI on the contrary, the documentation for the Kafka integration is quite intense and still fails to explain clearly how to integrate Kafka. The integration of Kafka is pressed into the SI-way of doing things, which adds extra complexity. Other documentation, e.g. on Stackoverflow is also less plentiful and less helpful than for Camel.
My conclusion: cobbler stick to your trade - use Spring as a container and Camel as system integration framework.
It really depends on what you want to do. If you need to extend something to build your own messaging solution Spring Integration has the better programming model. If you need something that supports many protocols without custom code, Camel is ahead of Spring Integration.
Having a small scale shootout is a very good idea, just make sure you're trying to do the type of things that you'd typically be doing in the project.
--disclaimer: I'm a Spring Integration committer
Most comparisons of Camel and SI that I've seen don't take the following into account:
1.) The effect that Spring Boot has had on developer productivity for Spring Integration
2.) The effect of Spring XD has had on making Spring Integration applications available with no code compilation - also Spring XD sources and sinks are simply Spring Integration channel adapters, when you're looking to extend Spring XD.
3.) The effect of Spring XD has had on making unifying Spring Integration, Spring Batch, Spring Data (+Hadoop!) in one stack, effectively bringing batch and stream processing, HDFS/Apache Hadoop support, and much more to Spring Integration.
4.) The effect of the soon-to-be-released Spring Integration 4.0 Java DSL https://github.com/spring-projects/spring-integration-extensions/wiki/Spring-Integration-Java-DSL-Reference
For your consideration,
/Pieter (disclaimer I work at Pivotal)
We are using Spring Integration for our application and now considering to move to Apache Camel as we encountered lots of issues with Spring Integration framework. Here are couple of issues.
The CachingConnectionFactory which Spring provides opens 1000's of idle connections in IBM MQ and there is no guarantee that these connections are reused. And still these connections will stay open forever which creates troubles on the MQ side. Had to restart the application every week in lower environments just to refresh the connections. Apache Camel also provides Caching and the connections seems to go up/down based on the load.
Spring doesn't provide mappers for QoS parameters. Even if you enable QoS, the delivery mode and expiration/timetolive properties will get lost (I am going to raise a JIRA issue for this). Apache Camel handles this and QoS parameters are sent to upstream applications and not dropping it.
I am right now working on issues with handling the exceptions and transactions with Apache Camel which Spring seemed to handle better with AOP.
Apache Camel is a very good framework and very complete too. But if your application uses spring, my personal advice is to use Spring Integration.
Spring Integration is the integration EIP complaint framework of Spring-Source ecosystem. It has excellent integration with the ecosystem: Spring boot, Batch, XD; even the core uses same abstraction starting from Spring Framework 4. Some of the messaging abstraction were moved in the framework, as proof that the basic messaging abstraction of Spring Integration is very strong. Now Spring framework for instance use the messaging abstraction for Spring Web, web socket support.
Another good thing in a Spring application with Spring integration respect to use Apache Camel is that with Spring integration, you can use only one Application Context. Remember that the Camel Context is a Spring context. if you have the chance of use a new Spring version, I suggest to use Spring Integration Java DSL for configuration. I use it on my new projects, and it feels more readable and clear. I hope that this reflection can help you for the your evaluations.
Actually, I would say FTP has graduated its incubation period. You can do a simple search on SI forums/JIRA to see what new features were implemented and bugs that were fixed. From various chatter it seems like there is already some production usage out of it, so I would suggest to give it a second look and of course communicate your concerns to us via
http://forum.springsource.org/forumdisplay.php?42-Integration
https://jira.springsource.org/browse/INT
Cheers
Oleg
Disclaimer: I am Spring Integration committer
One reason to use Camel over Spring Integration is when you need a more featureful EIP set. Spring Integration doesn't provide abstractions over things such as ThreadPool.
Camel does provide additional constructs for this simplifying some of the aspects of working with concurrent code:
http://camel.apache.org/camel-23-threadpool-configuration.html
If you have no need for this sort of thing and just want to connect file, JMS, FTP endpoints etc... then just use Spring Integration.
Camel act as middleware for application where one can perform data modeling, transformation of message values and choreography of messages.
If your current application is in Spring and require features which are supported by Spring Integration of EIP then Spring Integration is the best option else require more third party supports/protocols/file formats etc
Related
Spring seems to be deprecating its RMI:
As of Spring Framework 5.3, support for several remoting technologies is now deprecated for security reasons and broader industry support. Supporting infrastructure will be removed from Spring Framework for its next major release.
But I can't find any easy equivalent alternative to it. REST would sound like the best choice for simple stuff, but it does not cover solutions where the task is long running and/or a continuous flow of results is needed. So the implementation would be very absurdly painful with REST. Some consider submitting the tasks via REST to queues and then possibly querying for the results separately - but this sounds like an overkill and blows the amount of work needed to sky-high for something really simple that used to be available.
Is there a good alternative or some framework that uses the non-deprecated technologies and is officially available that deals with the above mentioned problems? When something is deprecated it usually indicates that something better is available that would be the better solution, so can somebody help me on educating me what it is?
Based on the spring documentation:
https://docs.spring.io/spring-framework/docs/current/reference/html/integration.html#remoting-web-services
I can say, that probably these alternatives remain in future versions, but I did not try them:
Jax-WS
Spring Web Services
AMQP
I feel, that Spring Web Services is Spring's favorite.
We will see when the 6.0 documentation is finished.
I have come across the same problem using Hessian. I think you still can make your own implementation. Spring only deprecates their own integrations to RMI technologies.
I think there are plenty of other technologies, but the message is clear. Spring will not make any own integrations.
I can think of these alternatives:
Hessian: still usable, but implement your own integration
gRPC
messaging (rabbit, pulsar, kafka, ...)
SOAP
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The Mule ESB project explains its difference to Spring Integration on its website. However, regarding dcterms.date 2012-07-19T18:43-03:00 of the document, the text might be outdated.
The main points of the quoted paragraph are
"Spring Integration takes [...] an 'application-centric' approach to integration".
"Rather than implement a shared bus, [...] Spring Integration is aimed at providing 'just a little' ESB-style integration to specific applications".
"Spring Integration is best suited to situations where a small number of components must be integrated, usually internally".
"[Spring Integration has a] very small number of supported transports and transformers available".
"[The] scope of Spring Integration is deliberately limited to small-scale integration within the Spring Portfolio context".
Are these points still valid? Does any more detailed and, if so, up-to-date comparison exist?
Mule ESB vs. Spring Integration
Recently, a new component called Spring Integration was added to the Spring Portfolio, which allows ESB-like functionalities and EIPs to be created and managed within the Spring Framework. Spring Integration takes what is known as an "application-centric" approach to integration.
Rather than implement a shared bus, which allows all integration and messaging between components and systems to be managed, administered, and configured centrally, Spring Integration is aimed at providing "just a little" ESB-style integration to specific applications by providing frameworks for implementing common EIPs such as a message bus and simple routing.
Due to its limited scope, Spring Integration is best suited to situations where a small number of components must be integrated, usually internally, and the infrastructure in question is made up of a large number of other Spring components. For anything more complicated, the lack of a common bus, coupled with the very small number of supported transports and transformers available for the young project makes Spring Integration unsuited for the task.
The advantage of using Mule ESB to handle integration in a Spring environment is that Mule ESB is not simply an ESB - it is an integration platform. Whereas the scope of Spring Integration is deliberately limited to small-scale integration within the Spring Portfolio context, Mule's intentionally modular architecture allows teams to quickly deliver the lightest possible integration solution for any scenario, from simple point to point integration to complicated SOA, cloud and partner ecosystem scenarios.
Full disclosure: I am the current a past Spring Integration project lead and have been a committer for over 10 years.
While it is true that Spring Integration promotes modularity and loose coupling within an application, it is also very well suited for integrating systems together without the need for a central ESB. I am personally aware of a number of very large enterprises that integrate all their business systems together using only Spring Integration, with no central bus server(s) to configure/administer.
Its POJO programming model makes it incredibly easy to customize/extend; if some transport/protocol is not supported out of the box, you can simply wrap it in a POJO and invoke it (or consider writing a more formal adapter and contribute it back to the framework!).
We are particularly excited that it forms the basis of the new and important Spring Cloud Stream.
You may want to take a look at DZone's recent Guide to Enterprise Integration which talks about Spring Integration as well as the competing technologies.
I've been using Spring for about a year, and I'm comfortable enough using it, but I've avoided jumping under the hood for the most part.
I'm tasked with upgrading a large, mission critical enterprise application, from Spring 3.0.x to Spring 4.1.x.
What are the best practices for making a large, inevitably finicky and complex change like this? (Anything above and beyond 'throw in the jar files and see what happens' and 'read the documentation here: http://spring.io/' would be very helpful)
The system:
Java 6 - jax-b/-p/-ws/, Apache Commons,
Spring 3.0.5 - the usuals (core, context, beans etc), MVC, AOP, ORM, JDBC, Acegi
Hibernate 3.5
Tomcat 6
0 unit tests or automated testing of any kind.
Maven dependency management and build automation.
Half controllers using annotations for request response mapping, half using simpleFormController pattern, half autowired, half hooked up with xml.
Hundreds of views, scores of controllers.
Steps I've taken so far:
Prepared a (mostly automated) regression testing script (so that I can ensure I haven't broken anything)
I've started reading through the 'upgrade guides' one at a time, "upgrading to 3.1", "upgrading to 3.2" and making notes on things that sound familiar, but I think I'd need to have a much deeper grasp of our system, and spring in general, before I could be confident of this as an exhaustive approach. This just generally feels like a haphazard approach, which is not what I want for such a complex change.
My questions:
What steps/procedures are considered 'best practice' in these for a job like this?
Does anything jump out at you as a 'gotcha' for a job like this?
Obviously, there won't be "standard" set of recommended practices because every migration/upgrade is different. Here're my thoughts:
Requirements, requirements, requirements
Regression testing script is great start. If there is a complete documentation of the features/functionality, then your "success criteria" for migration is straightforward.
If the documentation is incomplete/non-existent, then double and triple check to make sure that all 'requirements' are captured with your tests. Might be a good idea to create documentation too. And have the product manager/supervisor sign off on it. You'll be surprised at how many 'hidden' requirements exist even in simple systems. There is a big risk of underestimating the effort needed for migration without comprehensive requirement.
It is extremely critical to set the right expectations in terms of timelines. Perhaps an agile approach with biweekly demos of how much progress you've made will help keep everyone on the same page.
Spring projects have evolved a lot. Budget for learning time.
This could be a big gotcha. Spring projects and Java development have evolved a lot since Spring 3.x. Big changes include:
Java 8 features
JavaConfig (as opposed to xml configuration)
Acegi is now Spring Security
Spring projects typically use Spring Boot
Switch from Maven to Gradle for building projects
Full CI using Jenkins (or other CI tools)
Unit and integration testing have moved on to using annotations (and mock frameworks)
Well, it is not easy to answer you question since there are many things to be taken into account.
First of all I can suggest you to use the Migrating from earlier versions of the Spring Framework guide that's coming directly from the 'source'.
I would especially draw you attention to the 'Enforced minimum dependency versions' section that recommends you the minimum version level of some wide used libraries.
Obviously in the moment you insert these new versions they're bringing with them some transitive dependencies that might generate conflicts.
Take also a look to the dependency updates section.
Also remember to correctly define the scope of the dependencies in your pom files, since many of them could be provided by the infrastructure you're using (i.e. Tomcat).
I think you will be required to move to Java 7 or 8 and also Tomcat should be updated to version 7 or better 8.
Moreover try to automate as much as you can your building and testing environment with maven along with adopting a CI environment like Jenkins (or Hudson if you prefer the product).
It is also very important to perform unit testing of every single little method/piece of code, since it will make integration tests easier.
You should also become familiar with Spring 4.x new features and try to exploit them especially those regarding testing improvements.
A little resume of new features is the following:
Removed Deprecated Packages and Methods
Java 8 Support
Java EE 6 and 7 become the baseline
Groovy Bean Definition DSL
Core Container Improvements
General Web Improvements
WebSocket, SockJS, and STOMP Messaging
Testing Improvements with extreme use of annotations
Take also a look to Spring MVC Test Tutorial by Petri Kainulainen that can give you a lot of informations about testing.
You have to have answer to the following before you proceed.
Is the need to upgrade is only the libraries and runtime for some sort of dependencies ?
OR
You really want to get the most out of Spring 4.x ?
Once you decide this you can take proper course. Those regression scripts you have created will help in both the scenarios. If you can think of some crude throwaway utility that will hit every public api with some valid input and capture the output and be able t compare this in the both worlds that may help but it may not be applicable in your situation.
So if you want to get the benefit of the Spring 4.x I would suggest you focus on productivity aspects and create an inventory of these things.
You may redesign the whole app in Spring 4 as if it is a new application.
Once you can envision the future state. The next problem reduces to going from Point A to Point B i.e. a matter of best migration path.
From Migrating from Spring 3 to Spring 4, you would probably get some help from the Spring project's
Spring Integration 3.0 to 4.0 Migration Guide on Github.
Hope it helped!
This came as an interview question.
The interviewer asked me if you can use spring for all the purposes and get away without using any of the Java EE framework .
I said yes, but he asked me how about if the application is distributed and what is the point of application servers.
I am not sure about the answer.
Does Spring do everything that the Java EE framework does?
Well, Spring is wide. So you can review point by point. I'm not specialist in Java EE but I'm sure Spring can cover a lot (if not all) of Java EE concerns. And I'm pretty sure Spring can handle most of layers/concerns in an application.
First of all, Spring IOC. You can configure an object graph with Spring IOC. It helps at any layer configuring all the components you need to implement a layer.
Spring-MVC-Web: you can configure an MVC web component in order to handle and serve all web application requests. I think you can make something cool with it. Configure web responses and its necesary configuration with other business elements (including IPC - Inter Process Comunication).
Spring Security is heritage from Acegi. It's a web framework for defining role-defined access to web resources.
I'm not sure if Hessian is Spring's too. Anyway it's lightweight and it helps comunicating with components in other processes à la RMI.
Well... I'm not sure about persistence, but I thing Spring has templates for JDBC, Hibernate, and all, so it can help anyway (as suggestions indicate: JmsTemplate and RestTemplate are available for communication with other business components!).
The core thinking here is: you can make an app from scratch, so in all cases, Spring can provide a framework to ease the difficult/repetitive tasks on every layer. Does Spring does it? Yes.
Please check other features to see if Spring has something for it. I'd bet it.
Deep down, Java EE is a set of specifications (some of which have been contributed by Spring team!)
Spring's mission statement is to 'Simplify Java Development'
It does so using the following techniques:
POJO -> facilitates easy testing
DI -> promotes loose coupling
AOP -> promotes separation of concerns, maintainability etc
Templates -> provides a standard programming model which does the heavy lifting for you
Spring and Java EE do not have a "Vs" relationship.
Using the above techniques, the Spring Framework lets you build (Java EE) standards-based applications more efficiently.
>Does spring do everything that the Java EE framework does ?
Based on what I've said above, the question might be rephrased as 'Does Spring have support/implementations for all the technologies that comprise the Java EE specification?' -
Nope, but it does do what it set out to do and that is simplify development on most Java EE technologies.
That said, the trade-off for this simplification of Java development is that you need to now have significant amount of knowledge (of the Spring Framework) at your fingertips... (comes with practice and google :) )
>Can't we use Spring for distributed java applications?
Sure you can. Spring has a whole lot of Exporters/FactoryBeans and Clients(Templates) for most conceivable use cases.
Yes Spring can be used in a distributed application without Java EE. We have used it to send messages to MQ and update a database both within one XA transactions.
According to this article, Spring can definitely be used on its own in a distributed application.
http://www.wrox.com/WileyCDA/Section/Why-Use-the-Spring-Framework-.id-130098.html
http://www.artima.com/forums/flat.jsp?forum=276&thread=204508
Historically, (5 years ago?) Spring was weak in the distributed applications area, in particular database clustering. That is no longer a concern. I would say that Spring is going even further for distributed computing these days as they are vigorously pursuing cloud technologies which Java EE hasn't approached yet.
In my view the main benefit of Spring was that it did away with some of the more heavyweight components of the Java EE framework (Entity Beans, session beans) and replacing them with a lightweight alternative.
On of the main benefits of Spring as I see it, is that it decouples a lot of components and then uses XML or Annotations of wiring them together. That makes it easy to write Unit Tests (by injecting mock components instead of real ones), which wasn't something easily done when using heavyweight Java EE components (couldn't easily unit test EJB 2.1 Entity Beans).
A lot of Spring concepts have since gone into the Java EE standards, so I would argue that Java EE is no longer a heavyweight option, and Spring works will with Java EE components such as application server managed connection pools (via JNDI), transaction managers, queue managers that can very easily be managed using an application server which can provide additional functionality such as clustering, failover, load-balancing, serving web resources...
Having said that, the people behind Spring (VMWare) have their own application server (tcServer) which is based on Apache Tomcat and provides a lot of the glue used by spring, but is not considered as "heavy" as some of the traditional Application servers (Websphere, Weblogic).
I don't think so. Basically Spring is about integration between Java EE frameworks.
Use spring inegration framwork for this .
Use can uss Akka framwork for managing distributed applications with spring integration .
Akka uses the Actor Model together with Software Transactional Memory to raise the abstraction level and provide a better platform to build correct concurrent and scalable applications.
Take a look at the step by step tutorial that gives more information about how to build a distributed application using Akka framework.
In general, distributed applications are built in Java using Java-RMI that internally uses Java's inbuilt serialization to pass the objects between the nodes.
I am embarking on a new RIA project with Java on the backend. I'm the only developer, and the app is a line-of-business application. My current stack looks like this:
MySQL || Spring(JdbcTemplate for data access) || BlazeDS (remoting) || Flex(Cairngorm)
My question is: what changes can I make to improve productivity? Manually coding SQL, server-side entity objects, client-side value objects and all the Cairngorm stuff is obviously a drag, but I'm not sure what higher-level frameworks to introduce.
What Flex/Java stack has served you well?
Manually coding SQL
Hibernate is an option to cut this out.
One thing that may be of interest is Grails with the available Flex Plugin. It's built on Spring, Hibernate and BlazeDS, so it's all there for you. It was unbelieveably easy to get it remoting stored objects and responding to AMF calls. I was using this and then moved over to a RESTful E4X implementation as I found it a lot easier to debug and tweak as I could inspect the server output in a browser and have tighter control over exactly what I returned to my Flex app (lazy loading problems in collections using BlazeDS were a headache at times).
Here is a quick tutorial showing how easy the whole Grails + Flex Plugin stack is: BlazeDS in Grails
I would seriously reconsider using Cairngorm. In my opinion it's a pretty bloated framework that introduces a lot of abstraction you'll never use. Check out:
http://code.google.com/p/swizframework
http://www.spicefactory.org
Both introduce the concept of dependency-injection into your Flex app.
Also +1 for Hibernate. I would use the standard JPA annotations on a Java class and extend that with Hibernate Annotations as you find you need additional functionality.
Check out springsource.org's new Spring BlazeDS Integration Project
Spring BlazeDS Integration is a new
addition to the Spring portfolio, and
a component of the complete Spring Web
stack. This project's purpose is to
make it easier to build Spring-powered
Rich Internet Applications using Adobe
Flex as the front-end client. It aims
to achieve this purpose by providing
first-class support for using the open
source Adobe BlazeDS project and its
powerful remoting and messaging
facilities in combination with the
familiar Spring programming model.
As alternative to hand-coding sql, aside from hibernate, you might wanna consider JPA/Toplink. And since you are already from a Spring camp, check out Spring ActionScript (formerly known as Prana), it's an IOC framework for Flex. It solves many inherent problems in Cairngorm. Also a good IDE that supports Flex/Actionscript like IntelliJ IDEA 8.
Whats missing between Flex and BlazeDS is, it doesnt have any sort of landing page where you have a listing of all the available services by just typing a url on the browser (similar to webservice endpoint).
You can try GraniteDS. It's an alternative to BlazeDS, with an actionScript generator, Spring integration (an Spring security), and if you use an JPA implementation, help you with the Lazy Initialization (in a transparent way).