Comments on: When JBoss Seam Fails

By: vitamin k

vitamin k — Fri, 04 Dec 2009 22:41:50 +0000

Modern web applications are built using a number of domain-specific languages that interact with Java in various ways – JSF, regular expressions, SQL or HQL and various sorts of XML configuration files. Once Java start interacting with other languages, things start going wrong and static typing is no longer helpful.

By: Nicolas

Nicolas — Tue, 17 Nov 2009 17:12:55 +0000

As we see, all of these problem can or could be adressed.

It is possible to make/include validator in the build prcess and simply make the build fail if there is an error.

JSP and alike should not permit "script like" syntax, but only clean and statically typed code. It could be even included in the design.

I prefer to use a full object framework like GWT or Zk that permit to have static checks for many more part of my code that frameworks based on templates and script. In the long run it save a lot of time.

Oh and it not only static compiled programs give to you, but a much more common mistake : you misspelled your identifier. (And this in dynamic languages or scripts like JSP, it doesn't work).

Another good thing with IDE this time, is that they can give you all methods, valids identifiers and all with their type anywere you need it and instantly. IDE doesn't just detect error, they help you write a correct code in the first place.

By: Nicolas

Nicolas — Tue, 17 Nov 2009 16:12:55 +0000

By: philip andrew

philip andrew — Tue, 17 Nov 2009 07:54:06 +0000

If you use IntelliJ Idea it picks up all these errors in the IDE and highlights them in RED.
I'm not advertising their product, just state a fact.

By: Ashitkin Alexander

Ashitkin Alexander — Sat, 14 Nov 2009 21:46:11 +0000

for me it's a regular article for the subject 'man with axis can break it all'. IDEA has amazing seam support, so if you miss something – visit your oculist as the first step to an error free application.

By: kk

kk — Sat, 14 Nov 2009 21:40:46 +0000

Mistake #4: JPA named queries are validated when deploying, not at runtime.

By: Matt Drees

Matt Drees — Fri, 13 Nov 2009 19:49:38 +0000

"we consider badly reported errors as a real bug"

I love that mentality. I wish more projects had it.

By: Luxspes

Luxspes — Fri, 13 Nov 2009 19:49:05 +0000

How about a an article with the title: When JSR standards fail?
http://luxspes.blogspot.com/2009/11/jpa-myth-ec...

By: sannegrinovero

sannegrinovero — Fri, 13 Nov 2009 18:16:30 +0000

Hi, nice post.
You forgot a point: the names of injected components. An important issue, especially as the solution in Weld/Seam3 is so cool.
Also consider that using JBoss Tools you're pretty much covered: you can even refactor method names it will find and update the references in facelets. As mentioned above, IDEA also helps; noone is using Vim or notepad with Seam I guess.
About the Pattern problem, could it be considered a Java language limitation?
Everybody writing a regex should have some unit tests convering them, so you're sure they will at the very least compile.

By: Pete Muir

Pete Muir — Fri, 13 Nov 2009 17:22:02 +0000

Couldn't agree more :-)

Better error reporting is something we are working hard on for Weld/Seam 3.

By: Guillaume

Guillaume — Fri, 13 Nov 2009 17:10:57 +0000

@zef, your tests are very interesting. As a lot of people say, playframework try to be very good at this particular point. But there is no magic. We have to manage each problem specifically, trying to find the most interesting underlying exception for each particular error.

I would love to see a 'When Play framework Fails' post. I hope better results. But as I said there is still no magic in play. You will surely find badly reported errors in you try hard enough.

However I think that the difference with most projects is that we consider badly reported errors as a real bug.

By: Jan Groth

Jan Groth — Fri, 13 Nov 2009 14:04:04 +0000

@Stephen – just to mention the obvious: if you rely on IDE-highlighting, and overlook just a little yellow dotted line or so (-> BTW, I'm colorblind… ) the next level of quality assurance can be your customer calling…

By: Stephen Friedrich

Stephen Friedrich — Fri, 13 Nov 2009 13:40:53 +0000

I agree with all your points. For me the conclusion however is to use a smart IDE.
IntelliJ IDEA prevents all these mistakes by giving live warnings while coding:
#1: EL expressions are validated against the java beans.
#2: Page references in pages.xml are validated.
#3: Regular expression syntax is also checked while typing
#4: HQL queries in strings are fully supported including validation and code completion (in latest builds even with nested EL expressions like #{user.username})

IMHO there still is a fundamental difference in between these kind of languages (EL, HQL, RegExp) and dynamically types languages like Ruby.
For the first kind of languages it is at least theoretically possible to do strict static type checks. It is more an issue with language tools.
In Ruby all static checks have to be best guesses (correct me if I'm wrong).

By: Stephen Friedrich

Stephen Friedrich — Fri, 13 Nov 2009 13:37:59 +0000

By: Gavin

Gavin — Fri, 13 Nov 2009 13:13:01 +0000

As Emmanuel mentioned, some of these kinds of errors are actually detectable using our eclipse toolset, and we are definitely getting even better with JPA2 and CDI. (Typesafety was a major goal.)

But I agree with your broader point that things start to go bad once you leave Java.

By: Gavin

Gavin — Fri, 13 Nov 2009 13:11:20 +0000

By: Emmanuel Bernard

Emmanuel Bernard — Fri, 13 Nov 2009 13:04:24 +0000

Interesting feedback,
JPA 2 will bring a solution to Mistake #4 via the Criteria API
and I think I have a solution for Mistake #3 for Hibernate Validator 4 ( http://opensource.atlassian.com/projects/hibern... ): a compile time we will detect these type of errors

We are making progress. The idea is to represent more in Java and less in String, a move we have started a few years ago. It takes time though.

By: When Scala DSLs Fail « I am Zef

When Scala DSLs Fail « I am Zef — Fri, 13 Nov 2009 12:23:34 +0000

[...] Lift, more configuration is done in Scala code rather than in XML files like in a framework like Seam. Consequently, simple typing mistakes are typically caught by the compiler. One area where mistakes [...]

By: MAG

MAG — Thu, 12 Nov 2009 20:26:04 +0000

As far as I remember JBoss Tools for Eclipse does highlight error #1.

By: Zef Hemel

Zef Hemel — Thu, 12 Nov 2009 19:39:30 +0000

This is all just a long analysis section of an upcoming paper we're writing. And yes, there will be a solution in the end ;)