Visual Basic

      Visual Basic is a high level programming language which was evolved from the earlier DOS version called BASIC.

     Visual Basic is a VISUAL and events driven Programming Language. These are the main divergence from the old BASIC. In BASIC, programming is done in a text-only environment and the program is executed sequentially.

     The codes look a lot like English Language. Different software companies produced different version of BASIC, such as Microsoft QBASIC, QUICKBASIC, GWBASIC ,IBM BASICA and so on. However, it seems people only use Microsoft Visual Basic today, as it is a well developed programming language and supporting resources are available everywhere.

     If you are in business, you can also create business programs such as inventory management system , point-of-sale system, payroll system, financial program as well as accounting program to help manage your business and increase productivity.

we have many smart programmers who wrote interpreters and compilers that can translate human language like programs such as BASIC into machine language so that the computer can carry out the instructions entered by the users.

HTML

Webpages are written in HTML - a simple scripting language.

          * Hypertext is simply a piece of text that works as a link.

          * Markup Language is a way of writing layout information within documents.

When a browser opens an HTML file, the browser will look for HTML codes in the text and use them to change the layout, insert images, or create links to other pages.

   1. HTML is a language for describing web pages.
   2. HTML stands for Hyper Text Markup Language.
   3. HTML is not a programming language, it is a markup language.
   4. A markup language is a set of markup tags.
   5. HTML uses markup tags to describe web pages.
   6. HTML tags are keywords surrounded by angle brackets.
   7. HTML tags normally come in pairs.
   8. The first tag in a pair is the start tag, the second tag is the end tag.
   9. Start and end tags are also called opening tags and closing tags.

. Net Frame Work

 The .NET framework has two major components-- The Common Runtime (CLR) and the Class Library

The CLR is the foundation upon which the .NET Framework has been built. The runtime manages code at execution time and provides all the core services such as memory management, thread management and remoting. It also enforces strict type safety and ensures code accuracy in order to provide security and robustness to the applications. This capability to manage code at runtime is the distinguishing feature of the CLR. All code that is managed by the CLR is known as managed code while other codes are known as unmanaged code.

The Class Library is an object oriented collection of reusable types. It is comprehensive and the types can be used to develop command line applications or GUI applications such as Web forms or XML Web services. Unmanaged components that load CLR into their processes can be hosted by the .NET Framework to initiate the execution of managed code. This creates a software environment that exploits both the managed and unmanaged codes. The.NET Framework also provides a number of runtime hosts and supports third party runtime hosts

CLR Features

1. CLR manages memory, thread execution, code execution, compilation code safety verification and other system services.

2. For security reasons, managed code is assigned varying degrees of trust based on origin. This prevents or allows the managed component from performing file access operations, registry access operations or other sensitive functions even within the same active application.

3. The Runtime enforces code robustness by implementing strict type and code verification infrastructure called Common type System (CTS). The CTS ensures that all managed code is self describing and all Microsoft or third party language compiler generated codes conform to CTS. This enables the managed code to consume other managed types and enforce strict type fidelity and type safety.

4. CLR eliminates many common software issues like handling of object layout, references to objects and garbage clearance. This type of memory management prevents memory leaks and invalid memory references.

Web Developing.

   A web application consists of web components, static resource files such as images, and helper classes and libraries. The web container provides many supporting services that enhance the capabilities of web components and make them easier to develop. However, because a web application must take these services into account, the process for creating and running a web application is different from that of traditional stand-alone Java classes. 
 
   Server-side utility classes (database beans, shopping carts, and so on). Often these classes conform to the JavaBeans component architecture.
   Client-side classes (applets and utility classes).

   Web applications are configured via elements contained in the web application deployment descriptor. The deploytool utility generates the descriptor when you create a WAR and adds elements when you create web components and associated classes. You can modify the elements via the inspectors associated with the WAR.

XML Language

 XML is a text-based markup language that is fast becoming the standard for data interchange on the web. As with HTML, you identify data using tags enclosed in angle brackets Collectively, the tags are known as markup.

  But unlike HTML, XML tags identify the data rather than specify how to display it. Whereas an HTML tag says something like, "Display this data in bold font, an XML tag acts like a field name in your program.

  The tags in this example identify the message as a whole, the destination and sender addresses, the subject, and the text of the message. As in HTML, the tag has a matching end tag. The data between the tag and its matching end tag defines an element of the XML data. Note, too, that the content of the tag is contained entirely within the scope of the tag. It is this ability for one tag to contain others that lets XML represent hierarchical data structures. 

  Again, as with HTML, whitespace is essentially irrelevant, so you can format the data for readability and yet still process it easily with a program. Unlike HTML, however, in XML you can easily search a data set for messages containing,  in the subject, because the XML tags identify the content of the data rather than specify its representation.

JavaBeans Framework

    The JavaBeans Activation Framework (JAF) is included because JavaMail uses it. JAF provides standard services to determine the type of an arbitrary piece of data, encapsulate access to it, discover the operations available on it, and create the appropriate JavaBeans component to perform those operations.
 
    The JavaBeans Activation Framework (JAF) is included because JavaMail uses it. JAF provides standard services to determine the type of an arbitrary piece of data, encapsulate access to it, discover the operations available on it, and create the appropriate JavaBeans component to perform those operations.

    The Java API for XML Processing (JAXP) supports the processing of XML documents using Document Object Model (DOM), Simple API for XML (SAX), and Extensible Stylesheet Language Transformations (XSLT). JAXP enables applications to parse and transform XML documents independent of a particular XML processing implementation.

Java Servlets

  Java Servlet is a standard extension of java platform for web application developers in a simple contents technics for access the exist systems.

Java servlet technology lets you define HTTP specific servlet classes. A servlet class extends the capabilities of servers that host applications that are accessed by way of a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by web servers.

Servlets are Java technology's answer to CGI programming.

1.Efficient.
2.Convenient.
3.Powerful.
4.Portable.
5.Inexpensive.