What is Java - Java is a high-level, robust, object-oriented, and secure programming language.
Java was developed by Sun Microsystems (which is now a subsidiary of Oracle) in the year 1995. James Gosling is known as the father of Java. Before Java, its name was Oak. Since Oak was already a registered company, so James Gosling and his team changed the name from Oak to Java.
Platform: Any hardware or software environment in which a program runs, is known as a platform. Since Java has a runtime environment (JRE) and API, it is called a platform.
Java Example
Let's have a quick look at the Java programming example.
Example.java
class Example{
public static void main(String args[]){
System.out.println("Hello Java");
}
}
To compile:
javac Example.java
To execute:
Java Example
Parameters used in First Java Program
Let's see what is the meaning of class, public, static, void, main, String[], System.out.println().
The class keyword is used to declare a class in Java.
The public keyword is an access modifier that represents visibility. It means it is visible to all.
static is a keyword. If we declare any method as static, it is known as the static method. The core advantage of the static method is that there is no need to create an object to invoke the static method. The main() method is executed by the JVM, so it doesn't require creating an object to invoke the main() method.
So, it saves memory.
void is the return type of the method. It means it doesn't return any value.
main represents the starting point of the program.
String[] args or String args[] is used for command line arguments. We will discuss it in the coming section.
System.out.println() is used to print statements. Here, System is a class, out is an object of the PrintStream class, println() is a method of the PrintStream class.
We will discuss the internal working of system.out.println() statement in the coming section.
Java Applications
There are mainly 4 types of applications that can be created using Java programming:
1) Standalone Application
Standalone applications are also known as desktop applications or window-based applications. These are traditional software that we need to install on every machine. Examples of standalone application are 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 a dynamic page is called a web application. Currently, Servlet, JSP, Struts, Spring, Hibernate, JSF, etc. technologies are used for creating web applications in Java.
3) Enterprise Application
An application that is distributed in nature, such as banking application, etc. is called an enterprise application. It has advantages like 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 is called a mobile application. Currently, Android and Java ME are used for creating mobile applications.
Java Platforms: There are 4 platforms or editions of Java:
1) Java SE (Java Standard Edition)
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.
2) Java EE (Java Enterprise Edition)
It is an enterprise platform that is mainly used to develop web and enterprise applications. It is built on top of the Java SE platform. It includes topics like Servlet, JSP, Web Services, EJB, JPA, etc.
3) Java ME (Java Micro Edition)
It is a micro platform that is dedicated to mobile applications.
4) JavaFX
It is used to develop rich internet applications. It uses a lightweight user interface API.
1 like
Create and manage your profile
