Most of the computer languages require the source code to be translated into binary executable code with a compiler. This means that the final result of any program can only be understood by the specific operating system it was compiled on. For example, a computer program compiled on a Windows 98 machine cannot be directly transferred and run on a Unix machine. All this was changed by Sun Microsystem.
JAVA generally refers to a combination of three things: the Java programming language (a high-level, object-oriented programming language); the Java Virtual Machine (a high-performance virtual machine that executes bytecodes on a specific computing platform, typically abbreviated JVM); and the Java platform, a JVM running compiled Java bytecodes, usually calling on a set of standard libraries such as those provided by Java Standard Edition (SE) or Enterprise Edition (EE). Java started as a project called “Oak” by James Gosling In the year 1991,top software engineers of Sun Microsystems Incorporated tasked a group to develop a computer language that did not depends on platform specific compilers; thus creating a platform ‘independent’ language. After many years of research, this group succeed to develop the Java language.
This Java language is to some extent depends on the C++ programming language, but is not totally tied to platform specific compilers. Sun accomplished this by creating what is known as the Java Virtual Machine (JVM). The JVM is an application which converts Java source code to machine code on the fly. For example, if a Java program is written on a Windows 98 machine, it can still run under the Unix environment, because the JVM will interpret the code for Unix.
The software developers using Java need only to write one version of their application, and it will run on any computer that has a JVM; a feature Sun dubs “write a program once, compile it once, and run it anywhere”. Presently, JVMs are available for Windows 95, the Mac OS, Unix, and several other operating systems. All major Web browsers have JVMs built in them as well. This means that any individual who has a recent version of a Web browser on their computer does not need to install JVM separately
Between November 2006 and May 2007, Sun Microsystems made available most of their Java technologies under the GNU General Public License, in compliance with the specifications of the Java Community Process, thus making almost all of Sun’s Java also free software.
Configuration required For JAVA?
Java requires an average powered, modern computer which uses a 32-bit operating system. If you do not have such a computer will find poor performance when trying to run Java applications.
One question will arise in the minds of those who are interested in developing and using Java over a networked environment (e.g., the WWW), is security. Sun’s original design for Java specified that it was to be used in a networked and distributed environment. With this in mind, Sun made security one of the major requirements for the Java language.Java applications used across the world wide web banned illegal access to memory space, violation of access privileges, or illegal data conversions. This is not to say that Java security is infallible, but it is more stronger than that of other applications used across Web.
Performance of JAVA?
This Software”s performance has increased substantially since the early versions, and performance of JIT compilers relative to native compilers has in some tests been shown to be quite similar.The performance of the compilers does not necessarily indicate the performance of the compiled code; only careful testing can reveal the true performance issues in any system.
