Java is a General Purpose and Object Oriented programming language created by James Gosling from Sun Microsystems in 1991. The first publicly released of Java (Java 1.0) in 1995. Java is Based on "write once, run anywhere" (WORA) Feature, meaning that code that runs on one platform does not need to be recompiled to run on another. Java Programs are compiled to bytecode (.class file) that can run on any Java virtual machine (JVM) regardless of computer architecture.
Java is a programming language that produces software for multiple platforms. When a programmer writes a Java application, the compiled code (known as bytecode) runs on most operating systems (OS), including Windows, Linux, and Mac OS. Java derives much of its syntax from the C and C++ programming languages.
Let's have a quick look at java programming example. A detailed description of hello Java example is given in the next page.
class FirstExample{
public static void main(String args[]){
System.out.println("Welcome To java");
}
} According to Sun, 3 billion devices run java. There are many devices where java is currently used. Some of them are as follows:
There are mainly 4 types of applications that can be created using java programming:
It is also known as a 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.
An application that runs on the server-side and creates a dynamic page, is called web application. Currently, servlet, JSP, struts, JSF, etc. technologies are used for creating web applications in java.
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.
An application that is created for mobile devices. Currently, Android and Java ME are used for creating mobile applications.
There are 4 platforms or editions of Java:
It is a java programming platform. It includes Java programming APIs such as java.lang, java.io, java.net, java.util, java.sql, java.math etc. It includes core topics like OOPs, String, Regex, Exception, Inner classes, Multithreading, I/O Stream, Networking, AWT, Swing, Reflection, Collection, etc.
It is an enterprise platform that is mainly used to develop web and enterprise applications. It is built on the top of the Java SE platform. It includes topics like Servlet, JSP, Web Services, EJB, JPA, etc.
It is a micro platform which is mainly used to develop mobile applications.
It is used to develop rich internet applications. It uses a light-weight user interface API.
