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 */

 Unlike traditional online courses that charge a fee, limit enrollment and provide credit or certification, Moocs (massive open online courses) are usually free or low cost and can host hundreds of  thousands global participants.  Although MOOC have been around for years in the form of collective techie learning gatherings, participation in 2012 has ballooned at a rapid pace likened to FaceBook in its heyday.  According to The Year of the MOOCarticle in the New YorkTimes, edX, a nonprofit start-up backed by Harvard and MIT, had 370,000 registrants in the fall of its first official courses. This paled in comparison to the amount of students that Courseraattained in its first year of online learning opportunities, 1.7 million!

Will MOOCs Replace education as we know it?

Like any new trend, massive participation in online classes has its challenges. Lynda Weinman has ample experience when pointing out that they are by no means a replacement for formal education.  As a former digital animator, special effects designer and classroom college teacher, Linda paved the path for an earlier version of MOOC education in the mid 90’s when she founded Lynda.comas an aide to her own students. Over four million students and 2,200 courses later she’s confident when clarifying that many of the collegespartnered with Lynda.com use the tutorials as added features to their existing courses.  When asked in an interview with ReadWriteBuilders, if high technical companies look at online programs in terms of advancement as a supplement to traditional education or as a way for people to further their careers, Lynda feels that “it’sjust one example of something that you can do to enhance your attractiveness to potential employers. But [it’s also important to have] a portfolio and body of work, references that actually work out, showing that you had success in the past.”

MOOC Benefits:

Voice recordings are useful at any point in time. If you want to save a lecture (or presentation) that you are attending, or record a voiceover for a project, the iPhone can be your solution. You don’t have to use an old tape recorder, or a standalone recorder. The iPhone’s fantastic technology records high quality voice recordings on demand, whenever you need it.

To get started, look for an application named “Voice Memos.” Most likely, this particular application is found in your Utilities category by default. Once you open it up, you are greeted by a large microphone, indicating you are in the correct application. When you want to start recording, simply tap on the large red button in the bottom left, and you are on your way to begin recording. What is important about recording voices on this application to the highest degree of quality, ensure that your meter in the bottom is within the middle range; with the pointer in the red zone, your recording will be awfully loud, while otherwise, it will be too quiet. Finished recording? Simply tap on the square button, and you have your recording.

What can you do with these recordings? Once you have finished recording, you are able to now share this recording through email or even in a text message; email it to yourself so you can save it on your computer, and listen to it later, or start editing it to put into a movie production, or text it to a friend for their needs.

One of the most anticipated features that came on the iPhone 4S was a new thing called: Siri. Zooming out before concentrating on Siri, mobile assistants were the new rage. Beforehand, people were fascinated by the cloud, and how you could store your files in the Internet and retrieve it from anywhere. You could store your file at home, and get it at your workplace to make a presentation. However, next came virtual assistants. When you’re in the car, it’s hard to send text messages. It’s hard to call people. It’s hard to set reminders that just popped into your head onto your phone. Thus, came the virtual assistant: a new way to be able to talk to your phone to be able to do what you want it to do, and in this case, text message, or call people, and many other features. Apple jumped onto the bandwagon with the iPhone 4S and came out with the new feature: Siri, a virtual assistant that is tailored to assist you in your endeavours by your diction.

Getting started with Siri

To get Siri in the first place, you need an iPhone 4S; although you may have the latest updates on your iPhone 4 or earlier, having an iPhone 4S means you have the hardware that is required to run Siri on your phone. Therefore, if you are interested in using Siri, check into getting an iPhone 4S, as they are getting cheaper every single day.