What is Java and why is it important?


Introduction: 

Java, tally to the many of the technologies which affect our everyday lives to this very day, originated in California, under the purview of Sun Microsystems and a company founded in 1982 by Andreas Bechtolsheim, Vinod Khosla, and Scott McNeally. With that said, tech-savvy types focused to look more to the future and leaving the past behind, so if you find yourself more willing about the modern world of coding, or find yourself questioning just how influential Java has been to the world of technology then you really don’t particularly want a history lesson. You will be assumed to be the most likely looking for the modern applicability and expanding of a technology that has continued to evolve in a regular pattern in order to keep up with the times.

Java is a programming language which was designed to be concurrent, class-based and object-oriented, as well as a computing platform which was first released by Sun Microsystems in 1995. An enormous amount of applications and websites will not work without Java installed in it, and more are created every day. Denying yourself Java is like denying yourself from getting access to a technological infrastructure. Java is advertised, and esteemed for its fast performance, security, and reliability.

Java is a programming language which was designed to be concurrent, class-based and object-oriented, as well as a computing platform which was first released by Sun Microsystems in 1995. An enormous amount of applications and websites will not work without Java installed in it, and more are created every day. Denying yourself Java is like denying yourself from getting access to a technological infrastructure. Java is advertised, and esteemed for its fast performance, security, and reliability.

 

History of Java

Java was originally developed by James Gosling with his colleagues at Sun Microsystems during the early 1990s. Initially, it was called a project ‘Oak’ which had implementation similar to C and C++. The name Java was later selected after much thinking and is based on the name of an espresso bean. Java 1.0, the first version was released in 1995 with the tagline of ‘write once, run anywhere’. Later, Sun Microsystems was acquired by Oracle. From there, there has been no looking back. The latest version of Java is Java 12 released in March 2019.

The Java Platform

A platform is known to be the hardware or software environment in which a program runs. We've already here some of the most important and famous platforms like Microsoft Windows, Linux, Solaris OS, and Mac OS. Most platforms can be described as a collection of the operating system and underlying hardware. The Java platform is much different from most other platforms in that it's a software-only platform that runs on top of other hardware-based platforms.

The Java platform has two main components:

  • · The Java Virtual Machine
  • · The Java Application Programming Interface (API)

We have already introduced you to the Java Virtual Machine; it's the base for the Java platform and is ported onto many hardware-based platforms.

The API is a large collection of ready-made software components that give many useful capabilities. It is joined into libraries of similar classes and interfaces; these libraries are known as packages. 

As an environment which is independent of platform, the Java platform can be a bit slower with respectto native code. However, advances in compiler and virtual machine technologies are bringing performance near to that of native code having no requirement of threatening portability.

The terms “Java Virtual Machine" and "JVM" mean a Virtual Machine for the Java platform.

What is Java used for?

Before I go ahead with this, let me explain you about why you should choose Java. It is highly popular and has dominated this field from early 2000’s till the present 2018. 

Some of the applications of Java are listed below:

  • · Banking: It is used to deal with transaction management.
  • · Retail: It is a Billing applications which you can see in a store/restaurant are completely written in Java.
  • · Information Technology: Java is designed to solve implementation dependencies.
  • · Android: Applications are either written in Java or use Java API.
  • · Financial services: It is used in server-side applications.
  • · Stock market: To write algorithms as to which company they should invest in.  
  • · Big Data: Hadoop MapReduce framework is written using Java.
  • · Scientific and Research Community: To deal with huge amount of data.

Features of Java

Java offers bundle of attractive features -

  • · Platform independent language
  • · Rich standard library making it easy to code. You can create a whole stand-alone application using Java.
  • · Java helps in automatic memory allocation and deallocation (called garbage collection).
  • · It provides great performance as Java supports multithreading and concurrency, so making it a highly interactive and responsive language.
  • · Secure and simple

Main Method in Java 

Note that, just like any other programming language, every stand-alone program in Java should have a main method to execute.

Create a Test class and add some simple code to it.

There is learning in each line of this code.

  • · class – this keyword is used for creating a java class. When you start the program, you should give the command javac Test.java for the compiling process and java Test.java to execute. If you are using IDE, you have to just right click on the class and select Run.
  • · public – The public is an access modifier that indicates the visibility. The main method cannot have access modifier as private (access modifier). Private methods can be called only within the class, whereas public methods are visible to all.
  • · static – Variables and methods can use the static keyword. Why is the main method static? For static methods, we don’t have to create an object. Hence, we don’t have to create an object of Test to invoke the main method.
  • · void – if a method doesn’t return any value, its type is set as void.
  • · int, String – these are two of the many data types that Java uses. Because it also uses primitive types, Java is not considered a fully Object-Oriented language.
  • · System.out.println – out is a static field of the class System. This field stores the instance of PrintStream class. println() is the method of this class, that prints the required output to the console.

Let us slightly modify this program to get the name and roll number as inputs from the user. There are many ways to do this. For this code, let us use the most common method – Scanner class.

 

Components

JVM (Java Virtual Machine)

It is an abstract machine. It is a specification that provides a run-time environment in which the bytecode can be executed. It follows three notations:

  • · Specification: It is a document that describes the implementation of the JVM. It is provided by Sun and other companies.
  • · Implementation: It is a program that meets the requirements of JVM specification.
  • · Runtime Instance: An instance of JVM is created whenever you write a command on the command prompt and run the class.

JRE (Java Runtime Environment)

JRE refers to a runtime environment in which bytecode can be executed. It implements the JVM and provides all the class libraries and other support files that JVM uses at runtime. So JRE is a software package that contains what is required to run a program. Basically, it’s an implementation of the JVM which physically exists. 

JDK (Java Development Kit)

It is the tool necessary to: -

  • · Compile
  • · Document
  • · Package Java programs.

The JDK completely includes JRE which contains tools for programmers. The Development Kit is provided free of charge. Along with JRE, it includes an interpreter/loader, a compiler (javac), an archiver (jar), a documentation generator and other tools needed in Java development. In short, it contains JRE + development tools.