Author Archives: Jeanne Boyarsky

Static analysis for performance – the server side java symposium

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Overall, I was disappointed by the session. Most of it was about the performance anti-patterns and i was expecting more about the static analysis tool. There was only one slide with an example of how to detect a pattern using static analysis and I found it hard to understand,  It is easy to say to tell new developers not to do something.  It is hard to detect programatically.   Nevertheless, the points made are valid and here are the notes.

Is Java slow? Not on Intel for C at least.

What are root causes of performance issues?

  • Bad architecture, code or design
  • Configuration
  • [or database/network and not java at all, but that’s out of scope here]
  • Many ways to write incorrect code. Static analysis is not a replacement for traditional performance tuning

Types of analysis:

  • Code query systems – Explore relationships among program elements, Codequest and jquery in this space
  • Semantic code query systens – focus on behavior in addition to structure.  Yonita is in this space.  Yonita starts with bytecode to capture all detail. Then query in sql or prolog to find anti-patterns
  • Note that yonita is a prototype and not yet publicly available

Redundant work
Examples

  • JSF calling output text and the getXXX<> method makes a database call each time
  • get value for key several time.  Ok if took like Hibernate is caching it for you
  • make the same ajax call twice and then do something different than the result

Fix by caching the value
Showed patterns for detecting, it looks complicated!

Other anti-patterns

  • Fine grained remote calls – entity beans versions 1 and 2
  • One by one processing – adding one at a time instead of batching so the transaction, authorization and database all happen repeatedly
  • Return a lot of records and discard the results

I asked if the static analysis tools could detect all of the anti-patterns shown. The answer was that it is library specific. I didn’t get a clear yes or no as to whether one could write a rule.

Someone asked about complex configurations. The answer was the tools struggle with dynamic configuration like Spring and specific support of the tool is required.

Message driven architecture with spring – the server side java symposium

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Mark Fisher has a cool twitter handle @m_f_
Pardon the lack of formatting, there was just too much information to learn plus watch live demos and type lists on an ipad. I will clean it up over the weekend. [cleaned up] Too much content is a good “problem” for a presentation to have.

libraries:

  1. Spring Integration
  2. Spring AMQP in release candidate mode.  Similar to Spring JMS but doesn’t hide it behind JMS. AMQP is an open wireless protocol.  Also use you set up a routing exchange and set up a routing key for clients to bind to.  For example news.star.us so can subscribe to different levels on broker. works with non Java clients

Events

  • Has been in Spring since the very beginning
  • interface ApplicationEventPublisherAware allows you to make a callback
  • Interface ApplicationListener is called when event occurs, can use generics to say what type of events you care about
  • Can do without forcing to extend spring interface as well

Messaging

  • JmsTemplate – prefer CachingConnectionFactory to ensure sessions are reused
  • Jms:listener-container defined in xml on a pojo
  • Or use AmqpTemplate instead of JmsTemplate to use amqp, works the same as jmstemplate, for example you can call receive/send methods
  • Amqp namespace released this week to support listeners
  • Showed demo with rabbitmq including using web ui to see how many messages on queue
  • RestTemplate for http messaging, can use HttpMessageConverters if need to be more specific

Mail

  • SimpleMailMessage to create a message and inject MailSender to send it, good for simple messages, there is a mime one for more complex messsages
  • Core Spring cannot receive e-mail. Spring Integration can

Polling

  • Better to use events/messaging and only poll when you have to
  • Lifecycle interface – start(), stop() and isRunning()
  • SmartLifecycle does those three plus autostartup, phases and adds a callback on stop

Scheduling

  • taskScheduler interface lets you schedule one time tasks, tasks at a fixed rate and tasks at a fixed delay
  • Trigger interface lets you control the next execution time along with the Trigger Context that gives information about the last scheduled/actual time
  • This means you don’t need quartz for simple operations
  • The @Scheduled annotation lets you specify cron or fixed time/delay expressions instead of interfaces
  • Can also create your own annotations to externalize the cron expression so using your custom annotation without duplicating the configuration of the cron expression

Pipes and filters

  • Message can be any object as the payload with headers in a map, the message is immutable unless your payload itself is mutable
  • MessageChannel can do point to point or publish subscribe, set channel, types in xml using  and can also set whether async
  • A gateway can be one way or bidirectional
  • Can use @publisher to put the result of a method or argument to go on a channel as a side effect of calling the method
  • Filters return booleans
  • Router directs to proper channel name
  • Can route on payload type, header type etc
  • Can split/aggregate channels
  • Spring Integration 2.0 lets you use el to specify bindings, etc
  • Can chain when don’t need explicit channel names

What makes standards stick – the server side java symposium

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EnterpriseDB is talking about standards in the contest of PAAS (platform as a service). Looking at the forefront of a paradigm shift with cloud.

Java has been number one on the tiobe index for five years. Objective C is currently at number eight. It is an interesting measure because it uses number of jobs, books, etc to calculate rankings.  Java was an evolution of C++ and solved a problem.

Evolution needs to happen or there is that opportunity for something else to replace it.

J2EE was successful because the major companies backed it on day one. Part succeeded (servlets) while art failed (ejb) [jdbc listed as success, but that isn’t jee]. EJB was too complex and alternatives came up like Hibernate and Spring.   The speaker did credit the mess up of EJB with people adopting Spring.

“open source became an alternative to a deficient standard”

Success criteria: solve a problem, developers love, standardize, be open source, be first. Do not need all of these, but more help.  Also listed Microsoft support as a benefit

There were a few typos in the presentation which i found distracting.  Basically the session was a history lesson with some interesting points. I was relieved was not a sales pitch.

Once people move on, they don’t come back. Even though EJB 3.1 is “as good as” Spring, people have already switched.
Who will own the cloud? Who knows? Time will tell.