Java Basic Introduction

  What is JAVA:-

Java is a computer programming language that is concurrent, class-based, object-oriented, and specifically designed to have as few implementation dependencies as possible. It is intended to let application developers "write once, run anywhere" (WORA), meaning that code that runs on one platform does not need to be recompiled to run on another. Java applications are typically compiled tobytecode (class file) that can run on any Java virtual machine (JVM) regardless of computer architecture. Java is, as of 2014, one of the most popular programming languages in use, particularly for client-server web applications, with a reported 9 million developers. Java was originally developed by James Gosling at Sun Microsystems (which has since merged into Oracle Corporation) and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++, but it has fewer low-level facilities than either of them.

History:-

1. Java was designed by Sun Microsystems in the early 1990s.
2. Basic aim of java was to solve the problem of connecting many household machines together.
3. Project was unsuccessful because no one wanted to use it.
4. Earlier Name of Java : OAK
5. Creator of Java :  James Gosling  (the father of Java)
6. As there was another language called Oak , they decided to rename OAK. New name was given to OAK , OAK was renamed Java in 1994
7. Java was publicly released on : May 27, 1995
8. Java was targeted at :  Internet development
9. Applets Had early support from companies :Netscape Communications

Versions:-

Major release versions of Java, along with their release dates:

• JDK 1.0 (January 21, 1996)
• JDK 1.1 (February 19, 1997)
• J2SE 1.2 (December 8, 1998)
• J2SE 1.3 (May 8, 2000)
• J2SE 1.4 (February 6, 2002)
• J2SE 5.0 (September 30, 2004)
• Java SE 6 (December 11, 2006)
• Java SE 7 (July 28, 2011)
• Java SE 8 (March 18, 2014)

5 Principles of JAVA:-

• It should be "simple, object-oriented and familiar"
• It should be "robust and secure"
• It should be "architecture-neutral and portable"
• It should execute with "high performance"
• It should be "interpreted, threaded, and dynamic"

Sources:-

http://www.oracle.com/

                  wikipedia

http://www.c4learn.com/java/java-history-2/

Warning 

• This is provided for educational purpose only.  
• Though we have collected the contents from the above specified sources in the aim of providing the readers all the information at one place. 

Read More

What Is Compilier

• A program that translates an executable 
program in one language into an executable program in another language.

• we expect the program produced by the 
compiler to be better, in some way, than the original

Role of Compilers:

High-level programming languages provides following advantages -

• increase programmer productivity 

• better maintenance

• portable

but we require following Low-level machine details too! 

• instruction selection 

•  addressing modes

•  pipelines

•  registers & cache

• instruction-level parallelism

The Structure of a Compiler:

Multiple Phases

Modern compilers contain two (large) parts, each of which is often subdivided. These two parts are the front end, shown in green on the right and the back end, shown in pink.

The front end analyzes the source program, determines its constituent parts, and constructs an intermediate representation of the program. Typically the front end is independent of the target language.

The back end synthesizes the target program from the intermediate representation produced by the front end. Typically the back end is independent of the source language.

Advantage of  front/back end division 

This front/back division very much reduces the work for a compiling system that can handle several (N) source languages and several (M) target languages. Instead of NM compilers, we need N front ends and M back ends. For gcc (originally standing for Gnu C Compiler, but now standing for Gnu Compiler Collection), N=7 and M~30 so the savings is considerable.

The front and back end are themselves each divided into multiple phases. The input to each phase is the output of the previous. 

Sometime a phase changes the representation of the input.

For example, the lexical analyser converts a character stream input into a token stream output. 

Sometimes the representation is unchanged. 

For example, the machine-dependent optimizer transforms target-machine code into (hopefully improved) target-machine code.

Conceptually, there are three phases of analysis with the output of one phase the input of the next. The phases are called lexical analysis or scanning, syntax analysis or parsing, and semantic analysis

Read More

How to Show any Widget Only on Homepage in webpage

 

To show Widget only on homepage, add a conditional tag for with the widget you have used . Go to Template >> Edit HTML >> Search for the widget and add red coloured conditional tag below.

Normally, you can find the widget in "Mainblog/ Mainwrapper" if you put the Widget over blog post. I suggest you use a widget title and search the title in HTML editor. Thus you can easily find the widget. Now add the red coloured tag as shown in the code.

Example :

<b:widget id='HTML5' locked='false' title='Testing Widget' type='HTML'>

<b:includable id='main'>

<b:if cond='data:blog.url == data:blog.homepageUrl'>

<!-- only display title if it's non-empty -->

<b:if cond='data:title != &quot;&quot;'>

<h2 class='title'><data:title/></h2>

</b:if>

<div class='widget-content'>

<data:content/>

</div>

</b:if>

<b:include name='quickedit'/>

</b:includable>

Read More

Latest Updates Widget for Blogger

 It is one of the most attractive widget for blogger , is provide a quick navigation system for your visitors . it look like as :

Procedure:

1.      Go to Template > Edit HTML

2.  Now past the billow code in CSS

                           Or    

       Search  “  ]]></b:skin>  “ and past the billow code just above it

Code:

.samazhlo {

background: #4371CF;

position:absolute;

float: left;

padding: 0 10px;

height: 32px;

line-height: 30px;

color: #FFF;

font-family: Oswald,arial,Georgia,serif;

text-transform: uppercase;

font-size: 10pt;

margin-right: 10px;}

.head_brnews{

height:30px;background:#fff;width:100%;max-width:1250px;margin:0 ;border-style: solid ;

border-width: 1px;border-color: #cccccc;overflow: hidden;width: auto;margin-top:10px;}

.breaking-news{

float:left;

height:30px;

position:relative;

overflow:hidden;

margin-bottom:20px;

}

.breaking-news h4{

background: #9EC22D;

display:block;

float:left;

padding:0 10px;

height:32px;

line-height:30px;

color:#FFF;

font-family: Oswald,arial,Georgia,serif;

text-transform:uppercase;

font-size:10pt;

margin-right:10px

}

.breaking-news ul{

float:left

}

.breaking-news a:hover{

color:#333;

}

.breaking-news ul li{

float:left;

display:block;

list-style:none;

}

.breaking-news ul a{

padding:1px;

display:block;

color:#333;

white-space:nowrap;

float:left;

line-height:30px;

font-size:13px;

font-family: 'Droid Serif', serif;

display:hidden;

}

.breaking-news span{

display:block;

float:left;

padding:1px 10px;

color:#333;

font-size:12px;

line-height:30px;

}

3.    Now  past the billow code any where Between  <head>  &  </head>   where u want the widget to be display

       for example past it after the navigation bar code  </div>

code:

<div class='head_brnews'>

<div class='breaking-news'><div class='samazhlo'>Latest Updates</div> 

<script src='https://dl.dropboxusercontent.com/u/80436322/autoscroll.js' type='text/javascript'/>

  <script type='text/javascript'>

       var nMaxPosts =6;

        var nWidth = 100;

        var nScrollDelay = 70;

        var sDirection = &quot;left&quot;;

        var sOpenLinkLocation = &quot;N&quot;;

        var sBulletChar = &quot;&gt;&gt;&quot;;

</script>

<script src='/feeds/posts/default?alt=json-in-script&amp;callback=RecentPostsScrollerv2&amp;max-results=6' type='text/javascript'/>

  </div>

</div>

4.   Now save the template

That’s it……………….

Happy Blogging!

   By- TYD group

Read More