I will begin our blog on Java Tutorial with an incredibly important aspect of java development:  memory management.  The importance of this topic should not be minimized as an application's performance and footprint size are at stake.

From the outset, the Java Virtual Machine (JVM) manages memory via a mechanism known as Garbage Collection (GC).  The Garbage collector

• Manages the heap memory.   All obects are stored on the heap; therefore, all objects are managed.  The keyword, new, allocates the requisite memory to instantiate an object and places the newly allocated memory on the heap.  This object is marked as live until it is no longer being reference.
• Deallocates or reclaims those objects that are no longer being referened. 
• Traditionally, employs a Mark and Sweep algorithm.  In the mark phase, the collector identifies which objects are still alive.  The sweep phase identifies objects that are no longer alive.
• Deallocates the memory of objects that are not marked as live.
• Is automatically run by the JVM and not explicitely called by the Java developer.  Unlike languages such as C++, the Java developer has no explict control over memory management.
• Does not manage the stack.  Local primitive types and local object references are not managed by the GC.

So if the Java developer has no control over memory management, why even worry about the GC?  It turns out that memory management is an integral part of an application's performance, all things being equal.  The more memory that is required for the application to run, the greater the likelihood that computational efficiency suffers. To that end, the developer has to take into account the amount of memory being allocated when writing code.  This translates into the amount of heap memory being consumed.

Memory is split into two types:  stack and heap.  Stack memory is memory set aside for a thread of execution e.g. a function.  When a function is called, a block of memory is reserved for those variables local to the function, provided that they are either a type of Java primitive or an object reference.  Upon runtime completion of the function call, the reserved memory block is now available for the next thread of execution.  Heap memory, on the otherhand, is dynamically allocated.  That is, there is no set pattern for allocating or deallocating this memory.  Therefore, keeping track or managing this type of memory is a complicated process. In Java, such memory is allocated when instantiating an object:

String s = new String();  // new operator being employed
String m = "A String";    /* object instantiated by the JVM and then being set to a value.  The JVM
calls the new operator */

Javascript has a lot of features which are often overlooked by web developers, and one such feature is the ability to have timed events. If you do not understand what that means do not worry because all will be explained in this tutorial.

Timing events allow you to write code which will execute within a set amount of time. As an example, say you wanted to display a clock on your web page. You could use javascripts' built in timing functions to make the time change every second or every minute.

Of course there are other uses for such functions, but we will stick with a simple timer which creates a dialog box with the words Hi There on it every 3 seconds, that way you can get a feel for how to work with timing.

To get started we are going to need a basic web page. Just create a blank page and add the following code in the script tags:

There are a lot of articles you will find on the internet that talk about the tenants of having a successful professional career. From soft-skills to job relevant skills, there is an unending list of the do’s and don’ts for establishing a great career. However, a successful career in information technology commands some specific efforts and focus. As a result, it is critical to focus on these 4 key tenants that can help you establish a promising and successful career in Information Technology.

·         Be Multi-lingual– This is the analogy of Steve Job’s famous quote ‘Stay Hungry, Stay Foolish’ as it applies to Information Technology. Gone are the days when you could train yourself on a specific programming language say Java or C++ and code your way to a successful career. The best programmers of today and tomorrow are pushing the limits and becoming experts in one of more languages. Knowing more than one programming language instantly makes you more employable since you can add value to multiple projects that require different languages. If you need proof, IT professionals knowing more than one language can attract a salary premium of £10,000 . Additionally, there is no telling how dynamic technology is and by being open to constantly learning new languages you will position yourself to get technology jobs that did not exist a few years ago

·         Go Beyond the ‘How’, Focus On ‘Why’: A common theme with most information technology professionals is their ability to figure out the HOW or, in other words, applying their technical know-how in achieving the solution to a problem. This is especially true when you are working for a service based IT organization where your key job is to develop a solution for the client’s business problem. Yes, you are and will get paid to be good at the ‘How’ but to advance a career in IT; it will help you immensely to also start focussing on the ‘Why’. This stems from a famous quote by Einsten “If I were given one hour to save the planet, I would spend 59 minutes defining the problem and one minute resolving it”. In essence, spend time in understanding ‘Why’ are your trying to solve the problem before you get down with figuring out the ‘How’ part. The reasons for developing this mindset are two-fold. One, you will instantly distinguish yourself from thousands of other IT peers who are content with the ‘How’ part. Two, there is a good chance that you want to get ahead in your career not only as a programmer but as a system architect or a business solution consultant. This is where the habit of asking the right questions pertaining to why a certain IT solution is requires will help you build the right solution.

·         Focus on the impact and results (Financial impact):This may not apply to IT professionals who are early in their careers but is paramount for senior IT professionals. For the most part, IT departments are required to make sure that the systems and the solutions function as desired and help the business run efficiently. In other words, the key metric for success for most IT professionals is being extremely good at technology, languages and Quality Assurance. However, the times are changing! No longer is the Chief Information Officer (CIO) in charge of making IT decisions. With organizations closely guarding the ROI of their investment in technology, CIOs are increasingly required to be cognizant of the financial benefits of technology so that they can justify the spending on IT. No wonder than that CFOs are increasingly pressurizing CIOs to get their act together

It is said that spoken languages shape thoughts by their inclusion and exclusion of concepts, and by structuring them in different ways. Similarly, programming languages shape solutions by making some tasks easier and others less aesthetic. Using F# instead of C# reshapes software projects in ways that prefer certain development styles and outcomes, changing what is possible and how it is achieved.

F# is a functional language from Microsoft's research division. While once relegated to the land of impractical academia, the principles espoused by functional programming are beginning to garner mainstream appeal.

As its name implies, functions are first-class citizens in functional programming. Blocks of code can be stored in variables, passed to other functions, and infinitely composed into higher-order functions, encouraging cleaner abstractions and easier testing. While it has long been possible to store and pass code, F#'s clean syntax for higher-order functions encourages them as a solution to any problem seeking an abstraction.

F# also encourages immutability. Instead of maintaining state in variables, functional programming with F# models programs as a series of functions converting inputs to outputs. While this introduces complications for those used to imperative styles, the benefits of immutability mesh well with many current developments best practices.

For instance, if functions are pure, handling only immutable data and exhibiting no side effects, then testing is vastly simplified. It is very easy to test that a specific block of code always returns the same value given the same inputs, and by modeling code as a series of immutable functions, it becomes possible to gain a deep and highly precise set of guarantees that software will behave exactly as written.

Further, if execution flow is exclusively a matter of routing function inputs to outputs, then concurrency is vastly simplified. By shifting away from mutable state to immutable functions, the need for locks and semaphores is vastly reduced if not entirely eliminated, and multi-processor development is almost effortless in many cases.

Type inference is another powerful feature of many functional languages. It is often unnecessary to specify argument and return types, since any modern compiler can infer them automatically. F# brings this feature to most areas of the language, making F# feel less like a statically-typed language and more like Ruby or Python. F# also eliminates noise like braces, explicit returns, and other bits of ceremony that make languages feel cumbersome.

Functional programming with F# makes it possible to write concise, easily testable code that is simpler to parallelize and reason about. However, strict functional styles often require imperative developers to learn new ways of thinking that are not as intuitive. Fortunately, F# makes it possible to incrementally change habits over time. Thanks to its hybrid object-oriented and functional nature, and its clean interoperability with the .net platform, F# developers can gradually shift to a more functional mindset while still using the algorithms and libraries with which they are most familiar.

Related F# Resources:

F# Programming Essentials Training