Basics of Java Message Service - I

In perivous article, we have read about basics of messaging system and come to know that how messaging can help in quite flexible and abstract integration of various software applications. Now let us move further towards basics of Java Message Service (JMS), which can help us to implement the messaging concepts read till now.

JMS is a Messaging Oriented Middleware. Middleware is the software used to connect more than one software applications (distributed also) in quite flexible manner. Middleware can be of two typs, RPC based and messaging based. RPC based Middleware is one which provided synchronous integration between two software applications. Whereas, Messaging based Middleware (MOM) is one which inetgrate two software applications asynchronously using messaging concept. Certainly nowadays, MOM are quite popular where client can not wait for response from service and hence want a asynchronous request processing. JMS comes in this category. JMS can also be used for synchronous communication with some efforts, however, that is not something for which JMS comes in existence. It is devised specially to strengthen and standardize the messaging oriented middleware software.

Before JMS, there were many messaging solutions in market from various Industry players, like from IBM, Progress Software and Fiorano etc. Problem was, these products were not following any standard specification. So suppose, today you find that Software A is meeting your requirement and use it for implementation. After one year, you met with some new requirements, and then found that A can not meet these requirements but B has these new features. But, now it was not easy to replace the messaging software due to lack of any standard API implementation. JMS has solved this problem by defining a standard to implement the messaging systems with an abstract API. Now, clients can easily switch from one to other vendor anytime as per requirement without disturbing the implementation of application.

Hence JMS is a specification which defines an API allowing java based applications to utilize the features of any JMS compliant MOM software, without sticking to any one implementation. It provides a right level of abstraction from proprietary implementation of MOM systems. JMS is not an actual product. Actual products are still coming from indepdent software product companies like IBM, Progress Software etc. However, now, these products are adhering to the protocol defined by JMS specification, and hence following a standard approach with many of their specific advance features like load balancing, persistence, fault tolerance and administration etc. JMS is also implemented in J2EE in form of Message Driven Beans. Hence it becomes a intrinsic part of J2EE specification now.

Basic Concepts of Messaging System

JMS (Java Messaging System) was developed to cater the need of flexible integration design among various application or within application components.

In simple Java application, if we need to integrate one component/application with other, we have to have the reference of target with source. It means that one object must be aware about other object. It results into a tight coupling. It can be made flexible further by using different patterns like Factory, Service Locators and Directories but still objects used to be aware about each other type with a defined integration protocol like method signature. Now when architects want more flexibility, where one object is completely unaware about existence of other object and can simply say that I need this type of message. This is an ultimate flexibility in integration.

This type of flexible integration can be achieved using a messaging based simple design in java.  If we want to achieve this in Simple Java implementation, we can make a Message broker kind of component. This component can provide following facilities: 

1. Any object can register with it as message producer by specifying a specific type of message, which can be a plain string. Message broker will maintain an internal data structure to keep track of such message producers corresponding to their message types.  
2. Any object can register with message broker as message consumer. It will also specify a type of message for which it is interested to consume the message. Message broker will maintain an internal data structure to keep track of all message consumers corresponding to message types for which these wants the messages. 
3. Now whenever any message producer produce a message, it calls message broker API and hand over the new message to it. Message broker knows the type of message, so it searches all the message consumers registered for this message type, iterate over this list and hand over the message to each consumer. 

Basics of Java Class Loader

Java class loader is an interesting concept of Java Runtime. We know that in Java,  every executable code is stored  in .java files which are compiled to .class files. These class files are stored in file system  in plain directory structure or in jar files or probably using some other medium. When any java program runs, it needs the definition of referred class files to execute this code at runtime. Here comes the role of Java Class Loader. Whenever Java runtime needs any class file, it calls a component of Java runtime called class loader to load the desired class. Default class loaders of Java i.e. Bootstrap and System Class Loader has the logic to search for the class file in JVM and in  directories and jars included in classpath respectively. It assumes that if Java program is referring to java.lang.Object, then the definition of this class must  be somewhere on  classpath in  java/lang/Object.class hierarchy. So by default, it has the logic to search in directories and jars. Once it finds the class file, it loads it in memory, store it with in memory cache for future reference and return to the runtime. So class loader search for the class files only once, and stores it in memory data structure to be utilized on future calls. Java classes loaded from default class loader are considered as trusted classes and hence these have the access to all core classes of java library itself.

Now Java provide enough flexibility to users applications to define their own custom class loaders, which can extend the default class loaders, and can add custom logic; like to load the classes from a  network location or from database and so on. Working of class loaders generally used to be like; a custom class loader first ask the parent default class loader of Java runtime to load the requested class. If default class loader is unable to find the class, then extended class loader proceed to load that class using its specific loading algorithm.

High Level Design Considerations for Reporting Solution

Reporting is an important part of most business enterprise solutions. Even for end business users, value of software is directly  proportional to quality of reporting system it provides. In this article, we shall discuss about very high level design considerations for reporting system. We shall not go in depth of technology, but will  talk about the thought process and various considerations which helps in design and in choosing the right tool.

When we talk about reporting, it means we are providing the information stored by Enterprise Application in a form which can provide valuable business and operational information to various stakeholders. Data stored by Application might be in different format, like most of the operations are related to CRUD activities and processing of various business document. However, reporting requirements can be very different. These can be very simple like to show all order processed with summary of their values, and also can be bit complex where one want to see the summary of all operations held, trend of specific business operations, future forecasting of business depending upon current sale trend and market data and so on. That means that we need to maintain data considering reporting requirements of solution, otherwise, it will be a good level of processing at the time of generating the reports if database structure is not compatible.

Next to discuss is, how database structure required for reporting can be different than application general data structure. Here are some of the possible differences:-

• Operation database used to be highly normalized to ensure the data integrity and consistency. However, to generate the reports which may need bulky data processing, we may need to maintain data in de-normalized form so that related data can be found in same table/s without applying multiple joins.  
• Reporting database may need many indexes to speed up the searching operations while generating the reports. However same level of indexes can slow down the create/update/delete operations in Operational Database.
• We may need to do various calculations on Operational Data to generate the reports. If reporting data is different and is ported from Operational Data, these calculations can be done during porting and can be stored in database for fast access while generating the reports.     

What is Software Release Process

As software systems, development processes, and resources become more distributed, they invariably become more complex. Further, software products used to be in an ongoing cycle of development, testing, and releases. Moreover different platforms add more complexity to this. Hence it is quite understandable that there are many different dynamic pieces that must fit together seamlessly to ensure the success and long-term value of a product or project.

Release Process means a set of well defined steps which MUST be followed before giving any new project version to end users for use. These steps involves various components like:

• Planning of features/enhancements/support/bugs we are covering in this release 
• Versioning of releases
• Time line for release - release date for testing and for users
• Repository structure like branching in repository maintain the changes
• Trace-ability matrix to track the quality
• A good build system to ensure the quality deployments
• Test cases and procedures
• UAT management
• Release to production environment
• Procedures to revert the deployment in case of any failure
• Information to client and training wherever required

Release process is the core of a stable system. If engineering team is heart of the project, release process is like heart beat of the project. Stability of every release is directly proportional to the strength and quality of release process and how good are we adhering to it. Ideally Release process is so important that it is being kept at first step even before building the software. Because it is the prorces which will ensure a smooth and quality delivery to the end users. Software team responsibility is not only to build a great software, but also to deliver it to users on time as expected and with desired level of quality.

Role and Characteristics of Software Architect

Software Architect is a vague term, and is having varied responsibilities in different Organizations and Environments. However if we talk about well accepted concept, a Software Architect is responsible to architect the system and lead all technical initiatives in the system. Software Architect is actually a senior technical person and often an ex-developer who has acquired a good level of skills across the products and platforms and having good experience of life cycle of applications. So Software Architect lead the project (or projects) for all technology related activities. She is a technical lead, and hence should have good technical skills as well as should be a good leader also. She leads the whole team around architectural decisions and implementation, and around technology related quality aspects. Here is an abstract list of responsibilities from which an architect own some or all as per the environment: 

• Keep an eye on new technologies coming in market and pick which can add value to the system
• Prototyping for new tool or technology
• Submit proposals for the development of Project with a long term vision of System requirements and architecture both while keeping in mind the priorities of business
  
• Technical Documents
• Converting business requirements to technical level requirements, so that team can understand these
• Define over all architecture and interaction of various layers and components. A durable architectures, which is abstract enough to be independent of any third party API, and even abstract within different layers of system
  
• Bridge between developers, project managers, and business experts
• Good skills of communication to make every stake holder understand the technical decisions in their language
• Ensure the technical directions of system and choices among various available options
• Often have experience of mixed technology set or at least understand these 
• Mostly initiate the in-house framework development and define the roadmap for the framework development
• Suggest solution for complex problems in System
• Review the implementation process and design for performance and quality
• Set quality parameters
• Release various guidelines for implementation
• Mentor the team for technical knowledge
• Knowledge builing exercises and work as mentor for team
• Exploration of new technologies and tools, and propose right one to team
• Proposal for process and execution considering technlogical changes, requirements and project requirements

How to Design the Logo

When we talk about a famous brand, the first thing that comes to mind is its logo. The logo is the most important component of any brand. A logo must be appropriate, pleasing, attractive and should reflect the credibility of Company. An effective logo sets the public image of your brand, and therefore should be designed with careful thought and creativity. Designing a log for your own web site or company  is really an enriching experience. Your logo is a visual representation of everything your company stands for.

Now that you know what a logo is supposed to do, and what it should represent; you now should move ahead to learn what makes a great logo. You should learn few basic rules and principles of effective logo designing. Before you begin sketching, first decide, what message you want to give from your logo to viewers. Try writing that message and mission statement of your  company to help in deciding the look of your logo. Now think around this message and then visualize the logo, which appeals you first.

Here are some additional tactics and considerations that will help you create an appropriate company logo:

Dependency Injection and Aspect Oriented Programming

Inversion of Control (IOC), Dependency Injection (DI) and Aspect Oriented Programming are three popular keywords in Software Designing and Programming. But these terms are quite confusing to others and to each others some time. Let us try to understand what are these terms and how these are used.

If we think about Inversion of Control, it seems like we are changing the flow of control from, and a new King is coming in picture who will control all the flow now onward. Actually it is right. Earlier when we have started with Procedural programming, we tend to have control at single point. Later when we shift to OOP, we did better by decentralizing the logic and hence the control also to respective object. However, as we move on, we still find something missing which was hard coding of object dependencies on each other. If anytime, we need to change the implementation of a specific object, it means that we need to change the code and it may probably have some impact on implementation style. Then we strive hard to find the solution for providing such flexibility in the application and devised various design patterns like Service Locator, and Factory Pattern etc.This gave us good solutions by keeping knowledge of actual object implementation away from user object and hence gives the flexibility to change the implementation at any point of time. Things moves well, and applications used to be more and more flexible in design with increased use of such design patterns. However, one end of control was still in the hand of user object. It was still aware and the one who will initiate the factory or service locator to further get the right implementation of service. But desirable stage was, when user object is just aware about type of service it wants, not the source and actual instance of this service.....

How to Fix Common Installation Problems for Connectify

Connectify is a nice free solution to make your computer a Wi-Fi hot-spot. Sharing the internet from your computer sometimes become a basic need, like, if you are at home and your family want to explore the internet, or you are on a trip and won't like to purchase multiple modems to share the internet with your fellows. In such kind of scenarios, Connectify helps you to achieve exactly what you want. It can make your computer a hot-spot and other computers can connect to it like a Wi-Fi proxy server and can enjoy the internet.

Connectify (http://www.connectify.me/) is a free software, however, recently a professional version has also been released which will brings some commercial benefits to the company. This progress shows that Connectify development should be active in future also. So it may be a dependable software for long term.

Installing Connectify is easy. The steps are given below:

Is Micromanagement a Right Management Style?

This is a conflicting topic. However let us start from a generic concept which is, everything is good and bad both, and the difference comes only with context. So any thing can be bad at one point for few people, however can be good at the same time for others. Same applies to Micromanagement also.

What is micro and macro management? Management is about planning, execution and delivering the desired results with given resources in given time. Macro management is when you believe in your team and manage them considering their skills. If you bank upon the skills of your team members, and try to nourish their skills by giving proper guidance with a desired level of challenges, you will never feel like to go in details of every aspect of execution. Rather, you would like to spend your time on more productive work items, like planning the things which your team can not do, or other important activities like client management, resource management, and strategical planning. It does not mean to loose control on project, Project Control is an important aspect of Management. However, micro-management is about managing every aspect of execution yourself. Where team does not have the rights to take even execution level decisions and every new step is blocked for your approval. Where you are spending most of your time on what the team is doing and how this is being implemented, rather than to devote your time on other activities matching to your skills like planning for future. Such environment shows the lack of confidence in team, or manager expectations are very high from team and she thinks that work can not be done perfectly till she participate herself. This could be the personality traits of an individual or some kind of insecurity feeling or could be the control freak.