Extremely handy Java debugging trick

The Coder Lounge: Printpoints : Debugging by writing to console

Arquillian initially overpromises and frustrates, but delivers real benefits

Arquillian is changing fairly rapidly, and the Arquillian folks are paying a lot of attention to feedback. This post discusses Arquillian 1.0.0.Final, and more importantly the ShinkWrap Resolver and ShrinkWrap Dependency extensions. A lot has already improved since I wrote this, though most of it hasn't hit -Final versions yet.

---

After seeing a lot of talk, hype and excitement about Arquillian on twitter for several months, I finally got around to introducing it into a new project to give it a try. I'm told it'll make testing massively easier and save me tons of time, so using it is a no-brainer.

Tweet to @craigdevel After my recent experience I recommend that you start using it too - but you'll need to be prepared for some rough edges and the need for workarounds until a few point releases have gone by.

To jump straight to the summary of it all, click here, or read on for the whole experience.

Java EE 6 - Traps, pitfalls and warts list

Java EE 6 has the potential to be a great platform. It just needs plenty of cleanup, implementation bug fixing, and real-world use to get there.

One of the bigger issues is the significant array of spec inconsistencies and oversights that leave parts of the system working (or not working) in ways very different to one might expect. These issues can greatly increase debugging time and take important time away from productive development and into chasing issues in appservers, frameworks, and the specifications themselves.

I thought I'd make a list of some of the ones I've hit so far. I'm really hoping we'll see a Java EE 6.1 - a fixes-only revision that, unlike EE 7, focuses on polish and usability over adding new features. These are things I think are important to see covered by it.

The shortlist, explained in detail below:

You can't @Inject into a @FacesConverter. Use Seam 3 Faces to work around this. UPDATE: This should be fixed in JSF 2.1.

You can't @Inject into a JPA 2.0 EntityListener or an entity. Do a direct BeanManager lookup from JNDI or use Seam 3 Solder's BeanManagerAware to kind of hack around this; it's ugly. Lack of JPA 2.0 lifecycle hooks for EntityListener classes means Seam 3 Persistence can't fix this one. UPDATE Jan 2012: It appears that into EntityListener will be supported in JPA 2.1, but not injection into entities.

Completely avoid all use of javax.annotation.ManagedBean. It was obsolete before release, is only inconsistently recognised, duplicates JSF2 functionality that's also obsoleted by CDI's @Named, and should simply be removed.

Weld (CDI) before version 1.1.1 is extremely buggy. If using Glassfish 3.0, 3.0.1, or 3.1 you need to update weld-osgi-bundle to 1.1.1. See these instructions for Seam 3. UPDATE April 2012: These weld/glassfish issues are largely obsoleted by newer releases.

Mapping of application-local resource-ref resource names in web.xml to a global resource name defined in glasfish-web.xml or jboss-web.xml doesn't work for persistence.xml jta datasource references and isn't supposed to work. Ignore all the examples and official documentation that suggest it should, they work with direct JDBC and with Spring but not with JPA 2.0.

If you encounter mysterious silent failures or null pointer exceptions, you probably forgot to include beans.xml. Your container will not warn you about this at deployment or runtime even if CDI annotations are present on classes.

Many of these workarounds require the use of Seam 3 (ie: "let's finish the work EE 6 started") modules. Because of Glassfish bugs, some additional work is required to use Seam 3 on Glassfish versions prior to the yet-to-be-released 3.2. See this previous post for some information.

In addition to the genuine issues with EE 6, there's also the learning curve to contend with. A while ago I wrote a broad conceptual overview of EE 6 intended for those coming to it cold, rather than migrating from EE 5 or from Seam. I felt it was necessary because of the struggle I had getting started with EE 6 and the bugs that bit me and confused me during the learning process. Perhaps it'll benefit others here or even provide insight into areas of the documentation and tutorial that would benefit from improvement.

Now, for the details:

Kobo and long-unfixed bugs

This article is part of an extended series on Kobo development and investigation

---

Apparently I have to make this more obvious:

• Take a backup of your Kobo's SD card before doing anything. If something doesn't work, you can't fix your Kobo without this backup. I will not send you a backup.
• Any device hacking is risky. If you can't afford to break your device, leave now.

---

(This post is part of a series on the internals of the Kobo and Kobo Wifi eReaders. The rest of the posts are technically focused; this one was just prompted by increasing frustration with the device.)

I really like the Kobo. It has great hardware, a great price, and some pretty nice software running on it. Unfortunately, it also has some annoying bugs and limitations - many of which wouldn't be too bad,if only there was any sign they'd ever get fixed/resolved. some but not all of which have now been fixed in the 1.9 firmware.

I feel a little bad paying the Kobo out about these issues, because the Kobo folks were really great to deal with and really responsive early on. I've been absolutely blown away by how far beyond narrow-interpretation GPL requirements they've gone with their source releases (including full build scripts and config files) and how quick they were to update their releases when asked about them. Please keep in mind that overall the Kobo is an excellent eReader and the Kobo guys deserve our support for being one of the depressingly few companies who fully accept, understand and act on the obligations that fall on them in exchange for the free use of GPL-licensed software.

Drupal 7, PostgreSQL, unserialize, and bytea_output

I just found out that PHP 5.3's PostgreSQL PDO driver (as used by Drupal) is broken by the Postgresql 8.0 transition from octal to hex encoding for bytea. It passes the raw hex through to the app, including the leading x , causing PHP's unserialize() function to choke.

I'm using Drupal with Apache and PostgreSQL on Windows (sigh) because I'm writing up a step-by-step hand-holding guide for someone who needs to do some testing against our Drupal database. I wouldn't be using that configuration voluntarily ;-)

Drupal doesn't check that bytea_output is set to 'escape' as a workaround or do a sanity test to detect this fault, so the results are ... interesting:

Notice: unserialize(): Error at offset 0 of 27 bytes in variable_initialize() (line 749 of C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\drupal-7.0\includes\bootstrap.inc).

If anybody else lands up whacking their head against this for a while: just

ALTER DATABASE drupal SET bytea_output = 'escape'

to have your sanity restored.

The amount of breakage being seen in drivers really makes me wonder if the the octal to hex transition should've been done with an opt-in from drivers during negotiation or an explicit SET, rather than just making it globally default. But, hey, hindsight.

Three hours in

I'm three hours or so into my real work, after being side-tracked isolating and reporting Glassfish and Mojarra bugs. I just found another one in Mojarra, albeit a trivial one.

(Edit) I'd written a little rant about the problem I was trying to solve, in the assumption that I'd hit another limitation/bug in JSF2. Well, this time I was just plain wrong; I'd used an incorrect test to draw an invalid conclusion and from there ran down the path - from my previous experience, admittedly - of assuming that this, too, was a tools issue.

The correct answer is here: To permit null/empty/none selection in a h:selectOneMenu driven by a f:selectItems , just add a f:selectItem with no value before the f:selectItems.