About Java Programming Language :
This tutorial is designed java beginners in mind, so don’t take stress your all doubts will be got solved.Java is a programming language originally developed by Sun Microsystems and released In 1995 as a core component of ‘Sun Microcystems java platform. The language derives much of its syntax from C and C++ but has a simple object model and fewer low-level facilities.
Java applications typically compiled to byte code that can run on any java virtual machine regardless of computer architecture.
Features Of Java :
Following are the main Features of Java Language:
- Platform independent: Generally developed software languages depend on hardware and OS. however,java language does not depend on any specific hardware or OS. Example : The java program developed on windows can run on Linux without changing program. In short, you need not to worry about different type of archtitectures or need to migrate already developed program .
- Object oriented programming : In object – oriented programming, separate classes are created and then configured as one program. Class can be created in such a way, which can operate independently. The reusability of programs can be increased by using functions like inheritance or capsulization of class. Due to this development methodology , the development efficiency as well as maintainability increases.
- Simple network system architecture : Generally, network programming is difficult and challenging. However, network processes using Java are easy to describe and understand. So, comparatively, the network system programming becomes easy.
- Multi- threading: multi threading is a system with which one process can be run on one thread. Due to this, multiple processes can be run on multiple threads in parallel and thus multiple applications can be run simultaneously.Java supports parallel processing of threads at language level and so mechanism of synchronization can be achieved.
- Security : A function is provided which prohibits developed applet from accessing the local files. Basically, applet has access only to the files, which are kept on the servers from which the applet has been downloaded.
It is said that one cannot understand Java if he is not conversant with C or C++ language. However,it is not 100% true that one cannot understand JAVA if he or she does not know C or C++. Since the java ,C and C++ are similar languages and comparison is done among these language while teaching java, above mentioned thought is spread in software industry.
Understand JRF and JDK :
JRE is a java run time environment and JDK is a development kit, which is included in JRE . JRE is a set of essential softwares,which are required to execute programs developed in java. It is constructed by a package of class libraries and JVM essential to run java programs. JDK is a set of minimum essential softwares , which are required to develop programs in java language. It comprises of compiler, debugger, class library and JVM etc. You need not to install JRE separately if JDK is installed because JRE is already provided in JDK.
Though the name JDK has been changed to Java2 Platform SDK after the release of version 1.2, it is still represented as JDK in many cases. In this book also, it is referred as JDK.
Note : JDK comes with following 3 versions
- J2SE (Java 2 Platform, Standard Edition) : It is most commonly used Java development kit. You can create basic programs of application or applets using J2SE. We are using this version to explanation.
- J2ME ( Java2 Platform,Micro Edition ): It is used to develop embedded programs used for mobile devices.
- J2EE ( Java2 Platform,Enterprise Edition): It is used while developing the large-scale enterprise applications.