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 */

C# PROGRAMMING –MAIN DESIGN GOALS

C# is a popular programming language these days, and it was designed from inception to provide a simple, clean, general purpose programming language for those intending to work within the confines of Microsoft’s .NET framework.  Since then, it has been approved as one of the standard languages by both ECMA and ISO, making C# programming an essential tool in every programmers’ kit.

Different languages have different uses and specialties, and C# was designed for programmers to be able to use it to create different components for use in software that would be deployed and distributed en masse, to live use environments.  This means that designers had to really put an emphasis on making the actual source code extremely compatible and portable.  Those already familiar with C or C++ should definitely notice this emphasis.

Another particular point of emphasis during design was focus on internationalization of the language; it was intended from inception to be available all over the world, and to see all sorts of different implementations based on variance in regional programming technique.  The resultant use should help the language develop sophistication as it is refined throughout different versions.

.NET is a highly popular programming language from Microsoft that continues to rock the IT industry since its inception almost twelve years ago. Simply stated, it is a development framework comprising of multiple modules that helps in creating Web Applications, Windows Applications as well as Mobile Applications. The demand for .NET programmers saw a definite surge in the last decade - thanks to the evolution of the smart phones.

Listed below are some of the recent and prevalent aspects of .Net

ASP .NET - Web API

Microsoft considers Web AP I as the future of ASP .NET. The world of web is heading towards a simpler, lightweight, REST based services. Web API makes it possible with the ASP.NET MVC without the heavy lifting that WCF requires. jQuery could be utilized for displaying results in front end of the page as shown in the example in Microsoft site.

I suspect that many of you are familiar with the term "hard coding a value" whereby the age of an individual or their location is written into the condition (or action) of a business rule (in this case) as shown below:

if customer.age > 21 and customer.city == 'denver'

then ...

Such coding practices are perfectly expectable provided that the conditional values, age and city, never change. They become entirely unacceptable if a need for different values could be anticipated. A classic example of where this practice occurred that caused considerable heartache in the IT industry was the Y2K issue where dates were updated using only the last 2 digits of a four digit number because the first 2 digits were hard-coded to 19 i.e. 1998, 1999. All was well provided that the date did not advance to a time beyond the 1900’s since no one could be certain of what would happen when the millennia arrived (2000). A considerably amount of work (albeit boring) and money, approximately $200 billion, went into revising systems by way of software rewrites and computer chip replacements in order to thwart any detrimental outcomes. It is obvious how a simple change or an assumption can have sweeping consequences.

You may wonder what Y2K has to do with Business Rule Management Systems (BRMS). Well, what if we considered rules themselves to be hard-coded. If we were to write 100s of rules in Java, .NET or whatever language that only worked for a given scenario or assumption, would that not constitute hard-coded logic? By hard-coded, we obviously mean compiled. For example, if a credit card company has a variety of bonus campaigns, each with their own unique list of rules that may change within a week’s time, what would be the most effective way of writing software to deal with these responsibilities?