JAVA Introduction ( What is Java ?)
- Mahesh Bhat M
- Jun 22, 2017
- 3 min read
What is Java ?
Java is a programming language and a platform.Java is a high level, robust, secured and object-oriented programming language.
Platform: Any hardware or software environment in which a program runs, is known as a platform. Since Java has its own runtime environment (JRE) and API, it is called platform.
Example :
class Simple{
public static void main(String args[]){
System.out.println("Hello Java");
}
}
Types of Java Applications :-
There are mainly 4 type of applications that can be created using java programming:
1) Standalone Application
It is also known as desktop application or window-based application. An application that we need to install on every machine such as media player, antivirus etc. AWT and Swing are used in java for creating standalone applications.
2) Web Application
An application that runs on the server side and creates dynamic page, is called web application. Currently, servlet, jsp, struts, jsf etc. technologies are used for creating web applications in java.
3) Enterprise Application
An application that is distributed in nature, such as banking applications etc. It has the advantage of high level security, load balancing and clustering. In java, EJB is used for creating enterprise applications.
4) Mobile Application
An application that is created for mobile devices. Currently Android and Java ME are used for creating mobile applications.
Features of Java :-
There is given many features of java. They are also known as java buzzwords. The Java Features given below are simple and easy to understand.
Simple :-According to Sun, Java language is simple because: syntax is based on C++ (so easier for programmers to learn it after C++). removed many confusing and/or rarely-used features e.g., explicit pointers, operator overloading etc. No need to remove unreferenced objects because there is Automatic Garbage Collection in java.
Object-Oriented :Object-oriented means we organize our software as a combination of different types of objects that incorporates both data and behaviour.Object-oriented programming(OOPs) is a methodology that simplify software development and maintenance by providing some rules.
Portable : We may carry the java bytecode to any platform
Platform independent : A platform is the hardware or software environment in which a program runs.There are two types of platforms software-based and hardware-based. Java provides software-based platform.The Java platform differs from most other platforms in the sense that it is a software-based platform that runs on the top of other hardware-based platforms. It has two components:Runtime EnvironmentAPI(Application Programming Interface)
Secured
Robust : Robust simply means strong. Java uses strong memory management. There are lack of pointers that avoids security problem. There is automatic garbage collection in java. There is exception handling and type checking mechanism in java. All these points makes java robust.
Architecture neutral : There is no implementation dependent features e.g. size of primitive types is fixed.In C programming, int data type occupies 2 bytes of memory for 32-bit architecture and 4 bytes of memory for 64-bit architecture. But in java, it occupies 4 bytes of memory for both 32 and 64 bit architectures.
Dynamic
Interpreted
High Performance :Java is faster than traditional interpretation since byte code is "close" to native code still somewhat slower than a compiled language (e.g., C++)
Multithreaded : A thread is like a separate program, executing concurrently. We can write Java programs that deal with many tasks at once by defining multiple threads. The main advantage of multi-threading is that it doesn't occupy memory for each thread. It shares a common memory area. Threads are important for multi-media, Web applications etc.
Distributed : We can create distributed applications in java. RMI and EJB are used for creating distributed applications. We may access files by calling the methods from any machine on the internet.
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