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.

Since its foundation, HSG has been a leader in Business Rule Management Systems Training and Consulting services by way of the Blaze Advisor Rule Engine.  Over the years we have provided such services to many of the worlds largest corporations and government institutions whose respective backgrounds include credit card processing, banking, insurance, health and medicine and more, much more.  Such training and consulting services have included:

Create a wrapper object model in either Java, .NET or XML

Identify and catalog business rules

Develop a rule architecture within Blaze Advisor that isolates rule repositories as they relate to functionality and corporate policies

Configure, develop and implement a variety of interfaces to the rule engine from disparate systems ranging from mainframe applications written in Cobol to UNIX/Windows applications using Enterprise Java Beans, Windows Services, Web Services, Fat Clients, Java Messaging Services and Web Applications.

Review and update code to boost efficiency either by way of

    Removing functions calls within conditional statements

    Ensuring that database calls are essential or can be rearchitected in some other manner

    Employing the rete algorithm where necessary

    Paring down extensively large class models

    Deploying such appliations in multi-threaded systems

·         ...

Call us if you:

    are in need of Blaze Advisor Expertise
    are developing SMEs in Blaze
    want to speak directly with an expert (no placement agencies)
    want an affordable alternative to FICO
    want to work with an industry leader

One of the biggest challenges in pursuing a career in software development is to figure out which language you want to work. In addition to commonly used software programming languages like C, C++, C# and Java a lot of new programming languages such as Python, Ruby on Rails have surfaced especially because they are used by a lot of consumer based start-ups these days.

It could then be a daunting task to figure out the technical language you should learn which helps you prosper in a software engineering career no matter the technology advancements that happen in the marketplace. Learning a fundamental and universal language like C# could be a great start to your career as the language is very mature and extensively used by companies large and small

What is C#

Similar to Java, C# is a multi-paradigm, object oriented language developed by Microsoft. C# is intended for use in developing software components meant to be deployed in distributed environments. So in essence, learning C# can enable you to write applications for large and complex server side systems that use sophisticated operating systems as well as compact mobile operating systems such as Android

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 */