After working on this for weeks, I am pleased to announce the first release of VMware vSphere API and SDK Frequently Asked Questions. It includes 70+ questions and trustable answers in 6 different categories: General, Getting Started, Language Bindings, VI Java API, API Usage, Troubleshooting.
From now on, before posting any question to any forum please read this FAQ page. For the best readability, I decided not to allow comments on that page. But your feedbacks and suggestions are always important. Please feel free to use this post for comments and discussions. Based on your inputs, I will continue to enhance the FAQs.
I got quite a few SPAMs on my twitter last week. While it’s annoying to be spammed, I did pay a little attention to the spammers and noticed that their commonality: big number of tweets, 0 following, 0 follower.
These characteristics reminded me of the Java virtual machine technology to garbage collect unused Java objects. In Java, you don’t need to explicitly de-allocate memory as in C++. The Java garbage collector (GC) takes care of this for you. It looks at the objects to see if there is any reference to it. If not, it deletes the objects.
In the Twitter case, a follower is Read more... (299 words, estimated 1:12 mins reading time)
While reading the recent Dec 2010 issue of MSDN magazine, I found an article (Multiparadigmatic .Net, Part 4: Object Orientation) with misunderstandings on object oriented design. I was surprised that the author reached conclusions like, “squares aren’t rectangles,” and “no happy ending here.” The conclusions are based on misunderstandings of object oriented design.
Let me show you what the root problem is and how to get a happy ending. After reading this, you won’t be bothered by “squares aren’t rectangles.”
What’s the problem?
As most people already know, inheritance or generalization (I prefer the latter) is an important feature of OOD. Using it effectively can lead to a good object model and concise codebase. In an inheritance relationship, a subtype must maintain “IS-A” relationship with its super type, for example, a Student type IS-A Person. I think most people are just fine with this. Read more... (778 words, estimated 3:07 mins reading time)
When a developer learns a new programming language or API, the first thing is probably to try out a HelloWorld sample. As said, real programmers don’t read documents. Although I don’t fully agree on that, it has some truth in it.
In my own experiences, I normally continue with other samples after HelloWorld one. When something is not quite clear, I check out the API reference or read some tutorials. Anyway, I am not telling you how to learn a new language or API, but trying to make a point here on the importance of code samples for the developers. In my opinion, samples are the most effective way to empower your users.
I think you would agree with me, there are too many bad samples. Here are some typical symptoms:
- Too much boilerplate code to a point that the code illustrating the API usage got buried. Typical boilerplate code includes extensive exception handling, GUI, logging, etc. Some samples even have a common library that could confuse your users totally.
- Too many API calls in one sample. You may need several APIs for a use case, but don’t aim one sample for multiple use cases.
- Too much object oriented. Object oriented programming is a best practice for application development. But it could confuse your developers sometimes.
- Dependencies on other APIs. To run the sample, your users need to install other libraries which may or may not need extra configuration or tuning. To understand the sample, users need to understand additional APIs. Extra burden, really!
- Of course, typical bad smells of programming which are not unique for samples. For example, bad naming, unnecessary global variables, using object attributes for passing values between methods, etc.
Now, how you can develop great samples? Besides the best practices writing great applications, you want to follow the following guidelines: Read more... (589 words, estimated 2:21 mins reading time)
I attended Eclipse Day at Google headquarter today. It’s a great event packed with several great talks.
Mobile application is for sure a hot topic these days. There were several talks on mobile application development like Android Tools for Eclipse by Xavier Ducrohet from Google, Eclipse Sequoyah for Android App Developers by Eric Cloninger from Motorola, Tools for Mobile Web by Paul Beusterien from Symbian Foundation, and EMF for GWT by Ed Merks from Cloudsmith.
While sitting in the talk on Instantiations Eclipse Tools, I learned that Google bought the company 3 weeks ago. I expect Google will soon make WindowsBuilder, a famous WYSIWYG GUI authoring tool, free for GWT users, therefore further drive the adoption of GWT in competition with Flex, SilverLight. Read more... (268 words, estimated 1:04 mins reading time)
Web based applications become more and more popular. Not only normal Web sites but also enterprise management systems are adopting this to deliver the functionalities due to the benefit of zero installation on the user’s side.
There are a lot of Web Frameworks today, probably more than anyone can grasp. For each programming language, there is one or more Web frameworks that help you to create Web based applications. Choices are definitely good but may give you a hard time to decide which one is best for your project. More often than not, there is no single best one that suits all your need. In other words, you have to decide the best in the context of your problem.
What should be in the thought process to a decision? Read more... (698 words, estimated 2:48 mins reading time)
- Programming language. You have to decide what programming language to use for your Web applications. With the preferred language in place, you can only use the frameworks supported by the language. This usually limits much fewer options to your list. The most popular programming languages for Web applications are PHP, Java, C#.
The choice of your programming language is not a choice sometimes. The most rational choice is to use a programming language you and your team are already familiar with. If that happens to be C, you then want to go down your list. Learning a new programming language and a new framework can be daunting. Not long ago, I tried to learn the Lift framework based on Scala language, and found it’s not that easy at all.
If it’s a team project, you have to find one language that all or most people are comfortable with and at least one person are good at.
If you think Google is a superman and doesn’t need anyone, think twice. Yesterday in its Google I/O developer conference, it announced its Google App Engine for business. The notable features include centralized administration, a 99.9% uptime SLA and heightened security. It also announced the partnership with VMware on cloud portability.
Why does Google need VMware?
In short, it’s about Enterprise. As the “for business” in the name explains, the new service is targeted for enterprises which are not really Google’s strength. Read more... (266 words, estimated 1:04 mins reading time)
If you are a software engineer, you might have known Tiobe popularity index of programming languages. The index is updated on monthly basis. The following table shows the top 20 most popular languages this month.
The index caught many people’s attention this month because C regained its No.1 position. Java, used to be No. 1 for years, dropped to No. 2. Although percentage wise Java is still very close to C, the declining of Java popularity can be eye-catching. Read more... (194 words, 1 image, estimated 47 secs reading time)
Amazon released its SDK for Java last month. It’s a complete set of APIs that cover almost all the services from EC2, S3, SQS, RDS to SimpleDB. Overall Amazon has done a consistent job, but the SDK is NOT really object oriented. And that I think is critical for higher development productivity.
Structure of the SDK
Before explaining why it’s not quite there, let’s take a look at the structure of the API itself. The SDK includes many packages. For each service, you find two or three packages: basic, model, and possibly util package.
In each of the basic packages you can find the two interfaces, and two implementation classes. Let’s pick EC2 as a sample here. The AmazonEC2 and AmazonEC2Async are two interfaces and implemented by AmazonEC2Client and AmazonEC2AsyncClient respectively. More methods are defined in the synchronous than the asynchronous versions with the majority of them overlapping with similar method names.
AllocateAddressResult allocateAddress()
AllocateAddressResult allocateAddress(AllocateAddressRequest allocateAddressRequest)
Future<AllocateAddressResult> allocateAddressAsync(AllocateAddressRequest allocateAddressRequest)
The first two versions wait and get you results upon return. The third version doesn’t wait and gets the result later. Read more... (731 words, estimated 2:55 mins reading time)
Java is a static typing language, meaning you have to define a type before you can use it and the compiler checks the types for you. Some people like the static typing and others don’t. People like it would like even more into the language. Some others would prefer less typing. The rest don’t have strong opinions and are OK with both.
In the last several years, we actually see two opposite trends in Java programming: stronger typing and weaker typing. This blog analyzes in depth why these two trends happened and what do they mean for you. Read more... (1000 words, estimated 4:00 mins reading time)
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