J and I and Me

Random Thought about Google Dart

2011-11-08T09:31:00.000+01:00

Here are some thoughts about Google Dart and its possible usages. They are just wild ideas, I have no information whether they will actually be implemented or whether they are shared by anyone at Google:

Compiling Dart into JavaScript is a good idea. It means Dart is immediately usable on any platform. There is no other way to quickly get it out to so many developers. Users are not quickly to switch to new browser - think about IE6.
I originally expected that a Plug In and VM for Dart on Chrome would be released quickly. Now I think that would have been a bad idea. Chrome would have had a good support for Dart while the rest of the browsers would have been left in the cold. They would probably not use the Google VM - remember that they also have their own JavaScript VMs. It is also unlikely that they would create their own Dart VM. So the current approach create a level playing field and makes it more likely for Dart to succeed.
I think the Dart VM might be an option for Android - maybe not in the near term but probably in the long run. Also it might be enough for Google to have an alternative VM. It just means it has a stronger position if a deal with Oracle must be closed.
Dart is a good fit for Google App Engine (GAE). Isolates have just one thread - that is also what Google App Engine enforces. That has the advantage that GAE can restart isolates. Isolates can be snapshotted and migrated to other VMs - which is great if you want to react to different load by offloading work from a machine. Isolates can only communicate via ports - that allows you to minimize dependencies to the outside. Again that is great if you want to restart or migrate Isolates. It might also be a way around the limitation that GAE won't allow you to open sockets. Java without Multithreading and without the possibility to open sockets is hard and no fun - and that is why I believe Java on GAE ist not that great. This changes dramatically if you use Dart.

So we will see where this is headed. Remember the first days of Java: It was seemingly all about Applets. Now it is all about the server. Technologies might succeed in other areas than originally planned. If you are new to Dart - here is a presentation about Dart:

Google Dart

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Spring and Scala

2011-11-01T11:14:00.002+01:00

Scala is an interesting language that appeals to a lot of Java developers as it is statically typed - just like Java. However, Scala focuses on concurrent processing. The choice of frameworks for typically bread and butter issues that you see in Enterprise applications is rather limited. For that reason it makes sense to look at Spring as a very mature and established Java Enterprise technology and whether it can be used with Scala. So here is a presentation and some sample code:

Scala and Spring

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https://github.com/ewolff/scala-spring

adesso Now On slideshare

2011-09-26T11:26:00.000+02:00

My employer adesso AG is now on slideshare: http://www.slideshare.net/adessoAG/ . Most of the presentations are in German. There are quite a few already and of course there are more to come. I thought I would show three presentations here on the blog. The most popular so far is about security and JSF (German):

OWASP Top 10 : Scanning JSF

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Then there is this one about memory and performance analysis in Java - something I think every Java developer should understand (German) :

Mist gemessen? Java Performance und Memory Analyse

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And this one about Requirements Engineering (German) :

Eine kleine praktische Philosophie über das Requirements Engineering

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PS: Of course there is still my personal slideshare account with English presentations at http://www.slideshare.net/ewolff/

Cloud PowerWorkshop at WJAX

2011-09-08T10:30:00.000+02:00

This year at WJAX me and my colleagues Halil-Cem Gürsoy, Andreas Hartmann and Stephan Müller from adesso will present the Cloud Power Workshop for the first time. It will cover everything you need to know to implement application with Java for the Cloud. We will cover Google App Engine (GAE). It pioneered the PaaS Cloud approach and is quite broadly used nowadays. At the same time GAE has some limitations that you need to know about to successfully build application on the platform - in particular if you use Java. Then Cloud Foundry will be shown - it provides a very interesting approach to PaaS - because it supports relational databases and Tomcat which is quite a familiar platform for most Java developers. To develop Cloud applications successful you need to use novel architectures. We will cover principles like BASE and the CAP theorem. And we will show how to implement Cloud system with good scalability using RabbitMQ and a NoSQL database. Also Map/Reduce using Apache Hadoop will be demoed. Of course there will be lot of live coding and material to take away so you can try it at home. Take a look at the official announcement (German) - looking forward to see you there!

Keynoting ECSA 2011

2011-08-04T18:57:00.000+02:00

I feel honored to keynote with the subject "What Does it Really Mean to be an Architect?" the 5th European Conference on Software Architecture (ECSA 2011) in Essen, Germany. The conference takes place from 13-16 September 2011 to discuss the latest research and experiences in software architecture.

The range of topics includes service and component architectures, quality attributes of software architectures, product line architectures, management of architectural decisions, and enterprise architecture. Workshops on traceability and dependencies in software architecture, as well as software architecture variability, provide further opportunities for in-depth discussion.

Each day, keynote speakers from academic and industrial backgrounds will discuss perspectives on current trends and challenges in software architecture. The other keynotes are:

Interactive Ubiquitous Computing Systems (Albrecht Schmidt, University of Stuttgart)
Software Analysis as a Service (Harald Gall, University of Zurich)
Enterprise Architecture (Jörg Koletzki, E.ON IT GmbH)
Software Performance Engineering in Dynamic Environments (Raffela Mirandola, Politecnico di Milano)
Balancing Long-Term Research with Industrial Applicability (Magnus Larsson, ABB Corporate Research)

The detailed program and registration information can be found at http://www.ecsa2011.org - register online before August 14th to take advantage of the early registration rates!

Slides "Cloud Architecture" Online Seacon 2011

2011-06-30T14:15:00.000+02:00

The slides for the talk "Cloud Architecture" from Seacon 2011 are online:

Architectures For The Cloud

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You can also download them.

Slides and Pictures from Amazon Event

2011-05-27T16:41:00.000+02:00

Here are the slides from the Amazon event at JUG BB sponsored by adesso:

And here are some pictures:

Amazon CTO Dr. Werner Vogels

Attila Narin and Carlos Conde of AWS with me

adesso sponsored talk by Amazon CTO Werner Vogels at JUG Berlin Brandenburg

2011-05-24T10:00:00.000+02:00

On May 17th adesso AG sponsored an Amazon event at Java User Group Berlin Brandenburg. Today, Amazon is more than an online book store. Since 2006 Amazon.com, through Amazon Web Services LLC, has been offering developer customers access to in-the-cloud infrastructure services based on Amazon's own back-end technology platform.

After an introduction by me Werner Vogels, CTO of Amazon, gave the first talk of the evening.

He introduced the audience to the original Amazon IT system. Realizing that Amazon’s growth potential was limited due to the way the system was built, Amazon changed the system’s architecture drastically. Even the organizational structure was changed, forming teams that would each be responsible for one specified business service unit- including the development of the service as well as its operation.

However, even after the reorganization the engineers spent 70% of their time on scaling the infrastructure and only 30% on creating the new business logic. So the next step was to create a platform that would eliminate this burden and at the same time wouldn’t restrict the engineers. This was one of the starting points of Amazon Web Services (AWS) e.g. for virtual computers (EC2) and storage (S3).

Later on, services like SimpleDB - a very scalable data store - were developed. The current numbers for the services are very impressive: S3 currently stores 339 billion objects and every day Amazon adds the equivalent amount of server capacity to AWS that was once used to run all of Amazon in the year 2000 – when it was a $2.76 billion USD enterprise.

Next to talk was Attila Narin, Senior Manager at the Solutions Architecture of AWS. He gave an interesting presentation on the architectural principles for applications in the Cloud.

Our third guest speaker, Carlos Conde, showed the employment of Amazon Elastic Beanstalk which is an impressively easy to use infrastructure for Java applications.

With well over 150 participants the event was well received and gave a good insight into AWS and its Cloud services. The guest speaker’s talks emphasized the importance of Cloud services being the infrastructure of the next generation Dr. Werner Vogels gave an entertaining look behind the scenes of Amazon, its infrastructure and its Cloud offerings.

Thanks to all involved for making this possible!

adesso Sponsored JUG BB Event with Werner Vogels (CTO Amazon)

2011-05-06T10:12:00.002+02:00

adesso will be sponsoring an event of the Java User Group Berlin Brandenburg with Werner Vogels, CTO of Amazon. I had the pleasure to listen to Werner's talk back at JAOO 2006 (see my (German) blog post about the event. It was remarkable: Werner was the first to introduce me to the CAP theorem, now a well known foundation for distributed systems, and an approach that we now call DevOps.

During the event we will learn about Amazon Web Services, Architecture for the Cloud and AWS Beanstalk, the Amazon Java PaaS solution. If you are interested you can find more details at the adesso event page and registration form.

Seating is very limited - make sure to sign up ASAP. Looking forward to see you there!

Slides from JAX 2011

2011-05-05T13:02:00.000+02:00

My talks for JAX 2011 are done, so here are the slides:

Spring in the Cloud:

http://www.slideshare.net/ewolff/spring-in-the-cloud

Spring in the Cloud

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Cloud PaaS with Java:

http://www.slideshare.net/ewolff/cloud-paas-mit-java

Cloud PaaS with Java

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Future of Messaging: RabbitMQ and AMQP:

http://www.slideshare.net/ewolff/the-future-of-messaging-rabbitmq-and-amqp

The Future of Messaging: RabbitMQ and AMQP

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10 Typical Enterprise Java Problems

2011-04-29T11:56:00.000+02:00

This presentation shows 10 typical problems that I encountered during quite a few code reviews. I got mixed responses concerning this subject: During WJAX, JAX and also online at jaxenter the feedback was very positive. I did a similar talk at JAOO. There it seemed that the audience was already well aware of the problems or had already solved them. Not sure what the conclusion of that should be.

Nevertheless here are the slides:

10 Typical Problems in Enterprise Java Applications

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And
here is a video of the presentation in German.

The presentation is somewhat dated but I decided to upload it anyway. I think these problems are actually still far too common.

All You Need to Know About Cloud Foundry

2011-04-19T09:43:00.000+02:00

The last few days quite I have done quite some work on VMware's new PaaS offering Cloud Foundry. It is quite interesting because it means that VMware is entering the Public Cloud market. Also the code is Open Source so you can install it on your local machine or on other infrastructure. RightScale has already demoed Cloud Foundry on Amazon EC2 - you can find more information about Cloud Foundry here.

If you are generally interested in Cloud Foundry here are the things I have created:

Interview with Adrian Colyer, CTO SpringSource is here
English article is here
German article is here

Enjoy and make sure to visit cloudfoundry.org for the code and cloudfoundry.com for an account to the Public PaaS.

JAXLondon The Future of Messaging: RabbitMQ and AMQP Slides Online

2011-04-14T10:22:00.001+02:00

The slides for my talk "The Future of Messaging: RabbitMQ and AMQP" is now online at slideshare.

The Future of Messaging: RabbitMQ and AMQP

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Slides from BED Conference Talk about Java Cloud online

2011-04-11T11:22:00.001+02:00

BED conference in Berlin was quite enjoyable - thanks to all the speaker and attendees for making it such a success!

You can find the slides for the Java Cloud talk online at slideshare or they should also appear here:

Cloudy in Indonesia: Java and Cloud

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JAX London

2011-03-30T14:14:00.000+02:00

From April 11th to 13th the JAX will go to London. The last years it has been a pleasure to take part in the JAX in Mainz and WJAX in Munich.

I will do a talk about Spring Roo and one about AMQP / RabbitMQ, see my Speaker Profile. Also I will take part in the panel for the Spring Day which I had the honor to organiz. The program for the Spring Day is also online. Adrian Colyer will give a keynote about "Enterprise Applications in 2011: Challenges in Development and Deployment, and Spring's response.". Then Rossen Stoyanchev will talk about the new features in Spring 3.1. Then Russ Miles and Jonas Partner will talk about "Making sense of events: Strategies for Complex Event Stream Processing with Spring Integration and Pals" - sound very interesting! Another talk about a similar subject is "Spring Integration and Spring Batch in the Cloud" by Dave Syer. You should also read the interview with me about the Spring Day at JAX London.

See you there!

Berlin Expert Days

2011-03-29T09:42:00.000+02:00

Next week will see the Berlin Expert Days with the funky acronym BED. The conference takes place on Thursday, April 7th, and Friday, April 8th at the Freie Universität. It is intended to be a rather roots, low cost conference.

The program is online. I think there are quite a few nice session.

I will be doing two sessions, one about Java and Cloud and another one about Spring Roo. And I will also take part in the panel to have a nice discussion about Java with some other speakers and the attendees.

My colleague Kai Spichale will talk about the Apache Cassandra NoSQL database and Thomas Westphal - another fellow adesso colleague - will talk about Groovy and the CouchDB NoSQL database. And then Halil-Cem Gürsoy und Andreas Hartmann (both also from adesso) will talk about the currently most popular build tools - Ant, Maven, SBT and Gradle. And finally Andreas Hartmann and Stephan Müller (adesso) talk about security for JSF with the example of the OWASP attacks.

This is of course just adesso's part of the program - there are a lot of other great talks. So I am looking forward to meet you there - you can register here.

Article about CloudBees online (German)

2011-03-03T11:22:00.000+01:00

Just a short note: here is my German article about the CloudBees Java PaaS. Enjoy!

Dependency Injection Is More Than Wiring Components

2011-02-23T11:08:00.001+01:00

Dependency Injection is widely used nowadays. However, at least in the Java EE space this is narrowed down to "wiring components". I think configuring beans and injecting simple types is at least as important. The alternative is to read in configuration properties from files. Here is why I think DI is the much better approach for that:

Every project with a certain complexity has this problem. It needs to be adjusted to different users, use cases etc. A common problem should have a standardized solution
Reading in configuration files is not that easy. You have to handle exceptions if the file does not exist. You need to figure out what to do if a certain value is not set. You might want to have multiple files that can override configurations. I have to admit that I have seen projects in which the most complex code handled the configuration. Spring's XML configuration is already a powerful solution for this. And if you want to use properties files: The PropertyPlaceholderConfigurere allows to use those for configurations as well without writing any code. The PropertyPlaceholderConfigurere is very flexible - see its JavaDoc. But even if this is not enough: Using the BeanFactoryPostProcessor interface you can add your own configuration extensions.
As configuration is needed almost anywhere the class handling the configuration file becomes a dependency for a lot of classes. This is not a good design. Using DI the configuration will be injected and there is no such dependency.
Testing will also be hard if each class depends on the class handling the configuration. You will need a complete and correct configuration even for the smallest unit test. Otherwise the configuration cannot be read in. Changing the configuration for a specific test will either be impossible or the code for the configuration will become even more complex. Using the DI approach this is no problem as the configuration is injected and you can easily inject different values.

Of course this is not apparent during a short demo - but in real life DI for these kinds of applications it is a huge advantage.

Private or Public Cloud ?

2011-02-14T10:22:00.001+01:00

Currently Cloud is to a lot of people synonymous to "Public Cloud" i.e. some company provides virtual machines or a platform to deploy applications on. Examples are Amazon AWS/EC2, Rackspace, Terremark, Google AppEngine, force.com, vmforce etc. But an enterprise can also build its own Private Cloud. Companies like VMware offer all the infrastructure you need - and there are Open Source offering like Eucalyptus or OpenStack. Which route should you take?

Public Cloud Advantages

Getting started is very easy - basically a credit card is all you need.
Different service levels: While Public PaaS are quite common there is not really a lot of choice for private PaaS.
Almost unlimited ressources - you can easily add more servers and a lot of them if needed.
You would think that you have to ship data to the Public Cloud provider - actually using e.g. Amazon Virtual Private Cloud you can connect the Public Cloud to your local network using a VPN. I guess you can trust a computer in the Public Cloud at least as much as a (potentially compromised) computer in a DMZ
It is a logical next step after outsourcing operations or using hosting solution - it just provides more flexible.
Demanding SLAs are available for the services. For example multiple data centers for redundancy are hard to do by yourself and costly - but readily available in Public Clouds.

Private Cloud Advantages

You can provide exactly the kind of machines you need. A Public Cloud will only provide a pre defined set of configurations which might or might not offer what you need.
Legal regulations might make using public clouds impossible.
You might not want to ship your data into the cloud. But: Salesforce is making 2 billion dollar revenue - and the customer store all their customer contacts, order, revenue forecast etc in the Salesforce Cloud.
Compared to virtualized environment that are usually already in place a Private Cloud offers a self-service portal. So a user can create a new environment by himself. That means complex and unnecessary processes to approve new environments can be short cut and therefore productivity can increase. However, note that this is also the case for Public Clouds and it is a technological solution to an organizational problem.

Maybe the truth is in the middle: Only for high load you might want to offload work to the Public Cloud. But then you would need a common API for the Public and Private Cloud. Also the Public Cloud would need the same access to data as the Private Cloud - which is doable but might not be trivial. And you would still get different latency.

But: Cloud is in its core a business model. Instead of investing in infrastructure you just rent it - which drives down capital expenditure. This can only really be achieved in a Public Cloud because only then you don't own the infrastructure. Also a Private Cloud can only offer as many ressources as you have purchased.

More applications and data than you think might end in the Public Cloud. The most sensitive business data of quite a few companies are in Salesforce already. If important data cloud not be in the Cloud Salesforce would been doomed - but the reality is that they are very successful.

PS: I would like to hear your opinion. In particular if you are interested to give a talk about "How and why we built a Private Cloud successfully" I would like to hear from you!

Book Review: 7 Languages in 7 Weeks (Bruce Tate)

2011-02-10T14:42:00.002+01:00

I haven't done a book review in quite a while - so I thought it might be time to do one again. I have chosen Bruce Tate's "7 Languages in 7 Weeks". Bruce has written several books before that I found pretty interesting like "Bitter EJB" or "Better, Faster, Lighter Java".

I believe learning programming languages is a good way to improve as a Software Engineer - and it is one of the recommendation from "The Pragmatic Programmer: From Journeyman to Master" by Andrew Hunt and David Thomas. Even if you don't use the language in your everyday work you will get a different perspective on software development and learn new idioms.

In particular if you are used to Java it might be worth investigating a few new languages - especially those that run on the Java Virtual Machine (JVM).

Bruce covers the following languages:

Ruby: the famous OO language
Io: a prototype-based object-oriented language
Prolog: a logic language
Scala: mixes functional and object-oriented concepts on the JVM
Erlang: an almost functional language - used for the implementation of RabbitMQ, CouchDB etc
Clojure: A LISP-like language for the JVM
Haskell: A pure functional language

For each language there is an introduction and three sections explaining the concepts. The final section wraps up what has been learned and shows strength and weaknesses. All of the material is pretty hands on. I found the best way to use the book is to read it while sitting at the computer so that you can immediately try out what the book talks about. Actually I bought the eBook. So I have the PDF open while I can type in stuff in another window. The book also contains some small exercises for self-study.

The book is very helpful to get started in the languages. The exercises are simple and give you an achievable goal to work towards. It is easily possible to work through the book in much less than 7 weeks - which is a good thing. The exercises are probably good for one or two hours each. The choice of languages is good: Some more academic ones like Prolog or Haskell, some that are currently hyped like Scala and Clojure. I was surprised to see Io on the list and I think JavaScript would have been a better choice, in particular with the Node.js framework. Also I am missing pointers for a deeper dive. Also frameworks like Lift for Scala or Rails for Ruby might have been worth mentioning. A language always comes with a set of tools and frameworks. So looking at the language in isolation is a good start but then you need to care about the other parts as well. So maybe that is beyond the scope of this book.

Bottom line: This is a great, very hands-on book that I would highly recommend if you want to see what is currently going on in the programming language space or if you are just curious and want to broaden your horizon.

Preview: JAX 2011

2011-02-07T14:52:00.000+01:00

The annual JAX conference in Mainz is the main event for Germany's Java scene. For JAX 2011 I had the pleasure to organize the Spring Day again. The schedule contains:

Agim Emruli will start the day by discusssing "Web, RIA and mobile Aapplications with Spring". The client technologies are constantly evolving and this talk will present an overview about the current state of affairs.
Then Jürgen Höller will talk about the upcoming Spring 3.1 release. Jürgen is the lead engineer so we will get some information from the source.
Next is a talk by me about "Spring in the Cloud". I will show why Spring is a good solution for the Cloud and what you can do with it right now.
Oliver will discuss Spring Data. He is one of the developers on that project which will support relational databases as well as NoSQL databases.
Stefan Scheidt will show how to create a backend for an iPhone application using Spring Roo. This is a very good show case about Roo's capabilities.
Finally we will have a panel to discuss any questions and get some feedback. So all the speakers will be there and it will be highly interactive.

There will also be a basic Powerworkshop about Spring. This time I decided to do it based on Spring Roo which in my opinion is a great way to create Spring applications quickly. Also there will be an Advanced Spring Powerworkshop during which I will talk about advanced topics such as Patterns, architecture, migration to Spring etc.

During the conference I will also do a presentation about AMQP and RabbitMQ for Java developers and a presentation about Java PaaS.

Last but not least: We are planning a panel about the next decade in the Java world with Lothar Wieske and Stefan Tilkov. I am looking forward to this and I hope we will have some interesting discussions there. If there is anything you think we should be talking about I would be more than happy to hear about it!

So JAX 2011 will be quite a packed conference for me. But I am sure it will be a very nice conference again and I am looking forward to meet as many of you there as possible!

My Last Day at VMware / SpringSource - see you at Adesso!

2011-01-31T09:18:00.000+01:00

Today is my last day at VMware / SpringSource.

I joined SpringSource 2006 when we were about 25 employees worldwide. I was the first employee in Germany and started the operations here. Now - almost 5 years later - I have decided to move on. SpringSource has been dramatically successful and had a significant impact on Java and beyond. It is on a good way to the Cloud. The technologies are amazing. I wish SpringSource and VMware all the success possible and the best of luck. It was great to work with such a gifted team!

My new job will be Architecture & Technology Manager at Adesso AG, one of the leading German IT service providers. In this position I will be responsible for Adesso's technology strategy and the architecture in their projects. Adesso has a broad range of very interesting project which I am looking forward to work on. Also it has a great company culture as I already had the pleasure to experience.

I am very much looking forward to this position and the new challenges it will bring. Nevertheless it is a technology focused position - so you can look forward to more posts concerning technology and in particular Spring and the Cloud here!

Why I care about Spring...

2011-01-18T11:00:00.001+01:00

My blog post Spring vs. Java EE and Why I Don't Care mentioned a lot of challenges that I believe are crucial for the future success of Java. There are numerous projects that are working on these challenges. In this blog posting I will provide an update about those projects that VMware/SpringSource is investing in:

In the original post I mentioned Groovy/Grails and Spring Roo as new approaches to gain more productivity. Shortly after the blog post Spring Roo 1.1.0 (blog post) was launched and 1.1.1 shortly thereafter (blog post). The new releases include Google App Engine support, GWT support and database reverse engineering.
For NoSQL there is the Spring Data project (see project homepage) which supports many NoSQL and relational datastore. I believe this is the most important and most ambitious project in the NoSQL space for Java. The broad support for all the different data stores is quite unique.
Spring Social offers uniform support for most social web site, see project homepage. This is very important as social media change the way the internet is used and in particular offers new ways to become more popular on the web.
Another challenge is integration into existing applications. Spring Integration 2.0 was launched, see this blog post.
Besides the Caching abstraction in Spring 3.1 already mentioned in the original post there is also Spring GemFire to support our own Data Fabric GemFire in Spring.
Messaging: Support for AMQP is developed in the Spring AMQP project (see project homepage).

So if you are interested in these technologies: Give them a try! If there are any issue or if you want to see other features in the products don't forget to issue JIRAs for that. It is the feedback of the community that makes Spring and Open Source so vivid - that is your chance to add to that!

JAOO / Goto Conference 2010: NoSQL - an Overview (Emil Eifrem)

2010-10-21T14:33:00.050+02:00

This talk gave a general introduction to NoSQL. Emil is CEO of Neo Technology, the company behind the Neo4j NoSQL database.

Emil started by talking about the name "NoSQL":

He is unhappy about it - like almost everyone else
It it not "No to SQL"
It is also not "Never SQL"
It is rather "Not only SQL"

He gave four reasons why NoSQL is import

The exponential growth in data. I did some research and actually IDC says that 2009 the amount of data grew 62% to 800 billion gigabytes (0.8 Zettabytes). 2010 we will create 1.2 Zettabyte. This is clearly exponential growth - something we should be afraid of.
We are seeing more and more connected data. While we used to have tex documents it is now about hypertext, blog, user generated content etc.
Also the data is more and more semi structured. User generated content is a good example again. And also we are looking for information rather by using full text search and not detailed queries.
The architecture changes from integration with a common database to individual systems with their own private database each. This enables specific databases for specific challengers.

It is unlikely that relational stores will solve these problems. Also it means that NoSQL won't replace relational stores. They solve different problems and there is more than enough data for all kinds of databases.

Emil then discusses the four types of NoSQL:

Key-value stores are basically globally available Maps. Examples are Project Voldemort or Tokyo Cabinet/Tyrant. Their strength are the simple data model and they are great at scaling out horizontally. However, their weakness is the simplistic data model and they are a poor fit for complex data.
ColumnFamily / BigTable stores are a big table with column families i.e. you can have a lot of columns and structure them. Examples are HBase, HyperTable or Apache Cassandra.
Document databases store collections of documents with a document being a key-value collection. Documents might be represented as JSON etc. Examples are CouchDB or MongoDB.
Graph databases use nodes with properties and typed relationships with properties. Examples include Sones GraphDB, InfiniteGraph and Neo4j.

Challenges for NoSQL in his opinion are:

Mindshare and product usability
Tool support for development and operations
Middleware support in frameworks etc.

Very interesting was the demo that he did with Michael Hunger. It showed a prototype of an integration of Neo4j into Spring Roo. It showed how parts of the entity object could be stored in Neo4j and other parts in a relational store with JPA. This will probably become more and more common place: Certain parts of a customer are a good fit for a relational database while the relations to other customers or items might be a good fit for a graph database. This model allows to combine both approaches and use the better solutions for the problem at hand.

JAOO / Goto Conference 2010: Spring Framework 3.0 On The Way To 3.1 (Jürgen Höller)

2010-10-18T10:19:00.001+02:00

In this talk Jürgen showed the current step in the evolution of Spring i.e. the step from version 3.0 to 3.1. As most of the readers will be familiar with 3.0 I will not go into much detail concerning the first part of the talk.

Version 3.0.5 will be the last version for the 3.0 family. The first milestone for Spring 3.1 is scheduled for November - so it won't be long until you get something to play with.

Environment Specific Beans

One important feature will be environment specific beans. Applications usually run on several different environments. There is at least the Java SE environment you use for JUnit tests. You might do staging on a Tomcat server and production on a Java EE server. Beans that manage access to other system might be replaced by mocks for some of them. The goal of the environment specific beans is to deal with these differences in infrastructure while the deployment units are not changed. Usually operations insists that deployment units must not be changed between tests and production.

There are already ways to deal with this challenge. However, if this is supported as a first class part of the configuration it will be much easier and elegant to use. There are still discussions how this feature will be implemented so the details of this feature are not set
in stone.

The Spring Beans will be grouped by environment. The environment itself will be determined by an API that you can extend yourself for maximum flexibility. Placeholders will be resolved depending on the environment.

A possible syntax could be:
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClass" value="${database.driver}"/> <property name="jdbcUrl" value="${database.url}"/> <property name="username" value="${database.username}"/> <property name="password" value="${database.password}"/> </bean> <beans profile="embedded"> <jdbc:embedded-database id="dataSource" type="H2"> <jdbc:script location="/WEB-INF/database/schema-member.sql"/> <jdbc:script location="/WEB-INF/database/schema-activity.sql"/> <jdbc:script location="/WEB-INF/database/schema-event.sql"/> <jdbc:script location="/WEB-INF/database/data.sql"/> </jdbc:embedded-database> </beans>

As you can see the beans element is reused to also cover different environments. As mentioned above the actual implementation might be different - and of course the engineers are happy if you have any feedback!

Improvements for the Java Application Configuration

Java Application Configuration with @Configuration was already introduced in Spring 3.0. In the upcoming release it will be improved to also cover a functionality that resembles the XML namespaces. These namespace are used throughout the framework to configure features like transactions or aop. As the following code sample shows one possible implementation uses a fluent API - in this case to create something that resembles <tx:annotation-driven />.

@Configuration
public void AppConfig {
  @Autowired
  private DataSource dataSource;

  @Bean
  public RewardsService rewardsService() {
    return new RewardsServiceImpl(dataSource);
  }

  @Bean
  public PlatformTransactionManager txManager() {
    return new DataSourceTransactionManager(dataSource);
  }
  
  public TransactionConfiguration txConfig() {
    return annotationDrivenTx().withTransactionManager(txManager());
  }
}

Cache Abstraction

The Spring modules project offered some integration for caching and there is also a very basic cache abstraction. In Spring 3.1 there will be support for EhCache, GemFire, Coherence, etc. Several will be shipped with Spring core but it will also be possible to plug in custom adapters if necessary. The caching itself can then be configured using annotations for example:

@Cacheable
public Owner loadOwner(int id);

@Cacheable(condition="name.length < 10")
public Owner loadOwner(String name);

@CacheInvalidate
public void deleteOwner(int id);

As you can see methods can be marked as cacheable. This can be fine tuned using SpEL (Spring Expression Language). Other methods can be marked as invalidating the cache.

Conversation Management

This feature will allow a user to handle multiple orders in a web application simultaneously - for example in several browser windows or tabs. The state of these must be isolated from one another. The HttpSession is not an option for this because windows share the same
HttpSession.

Spring will manage the window id e.g. by using MVC session form attributes. This is a much simpler problem than the flow support in Spring Web Flow that allows for a simpler solution.

Keeping Up

Spring 3.1 will also support Servlet 3.0 on servers like Tomcat 7 or GlassFish 3. This will include the automatic registration of framework listeners which will make it even easier to use Spring in these settings. Also the support for JSF 2.0 will be improved e.g. for conversations.

Sum Up

Spring 3.1 optimizes Spring in several ways. As the version number indicated polishing and improvements are the main subjects. In particular the cache abstraction is interesting as nowadays a lot of applications need this kind of feature to build scalable solutions.