As part of our Java Tutorials program, we will list a number of interview questions to aid in a better understaing of Java and J2EE and, hopefully, provide a greater likelihood of getting a job.  Let us begin with the basics:

1. What is meant by J2EE?

J2EE is an abreviation for Java 2 Platform Enterprise Edition

2.  What is the purpose of J2EE?

The purpose of J2EE is to provide a component based platform in a multitier application model with transaction management, web services and reusable component support.

3.  What is the tier structure of the typical J2EE application?

A typical J2EE application consists of the following tiers/machines:  the client machine (browser/non-browser application), the J2EE server (an application server such as Oracle, JBoss, GlassFish, Tomcat) and a database.

The original article was posted by Michael Veksler on Quora

A very well known fact is that code is written once, but it is read many times. This means that a good developer, in any language, writes understandable code. Writing understandable code is not always easy, and takes practice. The difficult part, is that you read what you have just written and it makes perfect sense to you, but a year later you curse the idiot who wrote that code, without realizing it was you.

The best way to learn how to write readable code, is to collaborate with others. Other people will spot badly written code, faster than the author. There are plenty of open source projects, which you can start working on and learn from more experienced programmers.

Readability is a tricky thing, and involves several aspects:

1. Never surprise the reader of your code, even if it will be you a year from now. For example, don’t call a function max() when sometimes it returns the minimum().
2. Be consistent, and use the same conventions throughout your code. Not only the same naming conventions, and the same indentation, but also the same semantics. If, for example, most of your functions return a negative value for failure and a positive for success, then avoid writing functions that return false on failure.
3. Write short functions, so that they fit your screen. I hate strict rules, since there are always exceptions, but from my experience you can almost always write functions short enough to fit your screen. Throughout my carrier I had only a few cases when writing short function was either impossible, or resulted in much worse code.
4. Use descriptive names, unless this is one of those standard names, such as i or it in a loop. Don’t make the name too long, on one hand, but don’t make it cryptic on the other.
5. Define function names by what they do, not by what they are used for or how they are implemented. If you name functions by what they do, then code will be much more readable, and much more reusable.
6. Avoid global state as much as you can. Global variables, and sometimes attributes in an object, are difficult to reason about. It is difficult to understand why such global state changes, when it does, and requires a lot of debugging.
7. As Donald Knuth wrote in one of his papers: “Early optimization is the root of all evil”. Meaning, write for readability first, optimize later.
8. The opposite of the previous rule: if you have an alternative which has similar readability, but lower complexity, use it. Also, if you have a polynomial alternative to your exponential algorithm (when N > 10), you should use that.

Use standard library whenever it makes your code shorter; don’t implement everything yourself. External libraries are more problematic, and are both good and bad. With external libraries, such as boost, you can save a lot of work. You should really learn boost, with the added benefit that the c++ standard gets more and more form boost. The negative with boost is that it changes over time, and code that works today may break tomorrow. Also, if you try to combine a third-party library, which uses a specific version of boost, it may break with your current version of boost. This does not happen often, but it may.

Don’t blindly use C++ standard library without understanding what it does - learn it. You look at std::vector::push_back() documentation at it tells you that its complexity is O(1), amortized. What does that mean? How does it work? What are benefits and what are the costs? Same with std::map, and with std::unordered_map. Knowing the difference between these two maps, you’d know when to use each one of them.

Never call new or delete directly, use std::make_unique and [cost c++]std::make_shared[/code] instead. Try to implement usique_ptr, shared_ptr, weak_ptr yourself, in order to understand what they actually do. People do dumb things with these types, since they don’t understand what these pointers are.

Every time you look at a new class or function, in boost or in std, ask yourself “why is it done this way and not another?”. It will help you understand trade-offs in software development, and will help you use the right tool for your job. Don’t be afraid to peek into the source of boost and the std, and try to understand how it works. It will not be easy, at first, but you will learn a lot.

Know what complexity is, and how to calculate it. Avoid exponential and cubic complexity, unless you know your N is very low, and will always stay low.

Learn data-structures and algorithms, and know them. Many people think that it is simply a wasted time, since all data-structures are implemented in standard libraries, but this is not as simple as that. By understanding data-structures, you’d find it easier to pick the right library. Also, believe it or now, after 25 years since I learned data-structures, I still use this knowledge. Half a year ago I had to implemented a hash table, since I needed fast serialization capability which the available libraries did not provide. Now I am writing some sort of interval-btree, since using std::map, for the same purpose, turned up to be very very slow, and the performance bottleneck of my code.

Notice that you can’t just find interval-btree on Wikipedia, or stack-overflow. The closest thing you can find is Interval tree, but it has some performance drawbacks. So how can you implement an interval-btree, unless you know what a btree is and what an interval-tree is? I strongly suggest, again, that you learn and remember data-structures.

These are the most important things, which will make you a better programmer. The other things will follow.

Not getting any hits on your dating profile? It doesn’t mean you’re a loser. There are literally millions of computer dating profiles out there and dozens of free and paid websites to find a date. A dating profile is kind of like a resume for your personal life. To succeed, you have to learn a few tricks to stand out.

Tips to Improve Your Computer Dating Profile

1.  Make a Good First Impression

Filling out an online dating profile can be a daunting task. When you’re faced with all that blank space to write about yourself, it gets intimidating. The best way to improve your computer dating odds is to make a good first impression. Start with a good opening line such as a favorite quote or a personal motto you can easy build on.

The innovators in technology have long paved the way for greater social advancement. No one can dispute the fact that the impact of Bill Gates and Microsoft will be far reaching for many years to come. The question is whether or not Microsoft will be able to adapt and thrive in emerging markets. The fact that Microsoft enjoys four decades of establishment also makes it difficult to make major changes without alienating the 1.5 billion Windows users.

This was apparent with the release of Windows 8. Windows users had come to expect a certain amount of consistency from their applications. The Metro tile, touch screen interface left a lot to be desired for enough people that Microsoft eventually more thoroughly implemented an older desktop view minus a traditional Start menu.

The app focused Windows 8 was supposed to be a step towards a greater integration of Cloud technology. In recent years, Microsoft lagged behind its competitors in getting established in new technologies. That includes the billions of dollars the emerging mobile market offered and Cloud computing.

Amazon was the first powerhouse to really establish themselves in the Cloud technology market. Google, Microsoft, and smaller parties are all playing catch up to take a piece of the Cloud pie. More and more businesses are embracing Cloud technology as a way to minimize their equipment and software expenses. While it does take a bit for older businesses to get onboard with such a change, start ups are looking at Cloud computing as an essential part of their business.

But what does that mean for Microsoft? Decisions were made to help update the four decade old Microsoft to the "always on" world we currently live in. Instead of operating in project "silos", different departments were brought together under more generalized headings where they could work closer with one another. Electronic delivery of software, including through Cloud tech, puts Microsoft in the position of needing to meet a pace that is very different from Gates’ early days.

The seriousness of their desire to compete with the likes of Amazon is their pricing matching on Cloud infrastructure services. Microsoft is not a company that has traditionally offered price cuts to compete with others. The fact that they have greatly reduced rates on getting infrastructure set up paves the way for more business users of their Cloud-based apps like Microsoft Office. Inexpensive solutions and free applications open the doors for Microsoft to initiate more sales of other products to their clients.

Former CEO Steve Ballmer recognized there was a need for Microsoft to change directions to remain competitive. In February 2014, he stepped down as CEO stating that the CEO needed to be there through all stages of Microsoft's transition in these more competitive markets. And the former role of his chosen successor, Mr. Satya Nadella? Head of Microsoft's Cloud services division.

Microsoft may not always catch the initial burst of a new development in their space; but they regularly adapt and drive forward. The leadership of Microsoft is clearly thinking forward in what they want to accomplish as sales of PCs have stayed on a continuous decline. It should come as no surprise that Microsoft will embrace this new direction and push towards a greater market share against the likes of Amazon and Google.

Related:

Who Are the Main Players in Big Data?

Is Cloud Computing Safe for Your Business?

Is The Grass Greener in Mobile App Development?