Summa

Problem: Application began spewing out the following error when clicking on our Ajax-ified radio buttons:

java.lang.LinkageError: loader constraint violation in interface itable initialization: when resolving method "org.ajax4jsf.org.w3c.tidy.DOMNodeImpl.setUserData(Ljava/lang/String;Ljava/lang/Object; Lorg/w3c/dom/UserDataHandler;)Ljava/lang/Object;" the class loader (instance of com/ibm/ws/classloader/CompoundClassLoader) of the current class, org/ajax4jsf/org/w3c/tidy/DOMNodeImpl, and the class loader (instance of ) for interface org/w3c/dom/Node have different Class objects for the type

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Every once in a while, I’ll talk with somebody who’s confused about hashed passwords and the notion of cryptographic salt; what it is, and why you use it.  It’s really a simple idea that greatly enhances password security.  For those that are curious, here’s a 100,000 foot overview that glosses over many of the details but will give you the general idea.

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We have all been in projects where we use a combination of open source libraries, for different components of our architecture. We know theoretically that it should work, but alas, something blows up at runtime. If we’re lucky, we experience this on a weekly basis, but we don’t get lucky that often. The “Conundrum Solved” series will tackle some of these hair-pulling, sleep-depriving, grouch-inducing problems some of us at Summa have encountered in our projects. We hope that by sharing them with you, you’ll keep your hair, get enough sleep, and maintain a smile on your face!

Problem: Invalidly getting an InvalidStateObjectStateException thrown upon calling  merge(), even if there were no updates to the entity.

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The following blog post is written for any developer who has experienced working on a web based application, and during such project, altered the front end code (css, html, jsp, xhtml, aspx, php, etc.)…

After consulting as a UI developer on a range of web applications, I’ve run into many different coding behaviors/standards. These projects range from annoyingly brittle to flexible and well designed. Yet, in every single one of these web projects, I found a troubling coding “pattern” that would eventually lead to maintenance headaches. What is this horrible “pattern” you ask? It is… (drum roll) the prevalent usage of inline styling (CSS)… ugh.

I can already imagine some developers scoffing (laughing?) at the idea that inline styling could be “troubling”. Well, let me stop and boldly say… it is bad practice that will ultimately hurt a project in the long run.

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In a recent project the interface designer in my team asked whether we could disable the anchor tag (for expand/collapse) on the disclosure panel header and have a single button do the job, helping the user with a hint that this panel is actually expandable. I said OK, let’s see the DisclosurePanel javadoc. Suprise! All you can do is have a header and that itself is surrounded by the clickable anchor… time to extend Composite!

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It’s very tempting, given the power and ease of GWT, to jump in head-first and start building flashy new RIA applications for your customers right away. Slow down! Although I’m not generally an advocate of big design up front (BDUF), there are a few usability requirements that I think you’ll want to understand before you start coding – requirements that will fundamentally shape how you design your client-side GWT architecture, and therefore minimize re-work later.

So, toward the goal of evoking usability requirements, here are 6 important questions to ask your users or business owners:

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In this blog post I will provide an overview of considerations when integrating with a specific SaaS provider: Salesforce.com (SFDC). Salesforce.com is one of the most popular SaaS applications in the market and it is one the leading SFA (Sales Force Automation) solutions available to date. Salesforce.com provides very comprehensive integration capabilities. To narrow the scope of this post, I will focus on integrating through their Enterprise Web Service API. The discussion will also be focused on the technical aspects of the integration. There are several business and data modeling decisions that will not be covered here, but are covered at a high-level on an earlier post of this series.

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I came across this issue a couple years ago. It was surprisingly not-so-obvious to the developer, a good developer, who was sorting out a very elusive bug in a large Java application.

The symptom was that a Map of objects sometimes returned null when queried. The developer ran the code in a debugger and could see that the object was put into the Map. Yet, when the map was asked to retrieve the object, it was not found (even though it could be seen by inspection in the debugger).

Other objects were successfully stored and retrieved from the same Map.

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Applications for mobile platform are increasingly becoming an important market sector for all kinds of service providers. With the growing popularity of the iPhone and Apple’s well designed SDK, there are plenty of iPhone development project offerings even in this slow economic scenario. At Summa, we recently had a great experience developing a sleek iPhone application with a large user base. The purpose of this blog is to put together conceptual information along with project experiences around the important aspects of Objective-C’s memory management that would be helpful as one begins to delve deep into iPhone development.

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I have worked on a few large Flex applications, and almost everything about the platform delights me — it is quick to prototype, powerful in creating rich UIs. But it often frustrates me how difficult it is to handle run-time errors. There are posts, discussions and threads around tackling this issue. I have put together some of those ideas into a solution that I like, and wanted to share it.

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A few weeks ago I ran into a Java problem that took me an embarrassingly long time to solve — I won’t even tell you how long it took me to notice the source of the bug. It’s a relatively common mistake for starting developers — and clearly it even happens once in a while to experienced guys who aren’t paying attention. I figured I would detail my problem in the hopes that someone else out there might run across this post and save themselves half an hour or more of combing through their code.

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I know plenty of developers who, at a tactical level, have had success with static source code analysis tools, using them to help find and root out bad code smells. When PMD tells us there’s an empty catch block at line 207, for instance, we know exactly what to do.

At an aggregate level, however, code metrics are seldom so helpful or straight-forward. When seeing that a source tree has 160,000 lines of code or an average cyclomatic complexity of 4.12, our first thought is usually “interesting!”…followed shortly by “well, now what?”.

The problem is, in my experience, we often look at our code metrics in isolation, without good comparison points, leaving us to wonder whether the numbers we see are big or small, typical or abnormal, good or bad. In the end, it’s not clear what to do, if anything.

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XML Schema Definition (XSD) files define the structure and data types used in XML messages. XML schemas are a must-have in any application that relies on the use of XML. XML Schemas have become the universal definition language for integrating systems, as well as for defining common formats used for data interchange. Although there is not a “one size fits all” standard for creating schemas, it is essential to define XML Schema standards within IT organizations in order to ensure XML schemas can be easily reused, maintained and extended while minimizing impact on existing integrations. Without best practices and naming conventions, a project can end up with inconsistent schemas that may be too rigid or too relaxed to meet project requirements. On this blog post, I will go over ten practical tips for designing and building reusable XML Schemas. These recommendations can be used as a starting point for defining XML Schema standards within your organization.

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Say you need to hide internal application errors to your users in a friendly way and also notify the support staff of this exceptional condition. In this post you’ll find a way to do that in a JSF web app. The JSF flavor I’m using is Apache MyFaces 1.1 JSF implementation with the Tomahawk component which provides some extra functionality on top of JSF.

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For most developers coming from a Java or .Net background, there can be a rather steep learning curve when trying to pick up Objective C for iPhone development. This article serves as perhaps a starting point for these beginner iPhone Applications developers to get a sense of where the difference between the languages is, and where to concentrate their early learning efforts.

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