what is Java and Features of java?

What is Java?

• Java is a widely used object-oriented and class based programming language.
• One major advantage of developing software with Java is its portability.
• Once you have written code for a Java program and you can run it on any device.
• By using Java we can develop Mobile Applications, Web Applications, Gaming Applications, Desktop GUI Applications, Enterprise Applications etc.
• Java provides support for primitive data types int, char, double, and float. Hence, it is not considered a pure object-oriented programming language.
• Java has a unique feature that lets application developers Write Once and Run Anywhere which means that compiled Java code can run on all platforms that support Java without the need for recompilation.
• For this you'll need is JVM, JRE & JDK.

JVM:

JVM means Java Virtual Machine(JVM). It is an engine that provides a runtime environment. It converts Java bytecode into machine language. JVM is a part of the Java Run Environment (JRE).

JRE:

JRE means Java Run Time Environment(JRE). It provides the minimum requirements for executing a Java application and it consists of the Java Virtual Machine (JVM).

JDK:

JDK means Java Development Kit(JDK). It is a software development environment used for developing Java applications and applets. It includes the Java Runtime Environment (JRE).

Class:

A Class is a real-time entity use to represent/initialise the Objects. and in simple terms it is the blueprint of the objects.

Object:

A Java object is a member (also called an instance) of a Java class. Each object has an identity, a behavior and a state. The state of an object is stored in fields (as variables), while methods (as functions) display the object’s behavior. Objects are created at runtime.

Features of Java:
The 4 main features in java are:
1. Simple
2. Object Oriented
3. Platform Independent
4. Portable

Simple:
Java is a simple programming language and easy to understand because it does not contain complexities. It will run on any devices because where it requires less memory/resources.

Object Oriented:
Java is an Object Oriented Programming Language, which means in Java everything is written in terms of classes and objects.
The main object oriented conceps are: Class and Object, Encapsulation, Abstraction, Inheritance, Polymorphism.

Platform Independent:

Here platform means a type of operating system and hardware technology. Java allows programmers to write their program on any machine with any configuration and to execute it on any other machine having different configurations. In Java, Java source code is compiled to bytecode and this bytecode is not bound to any platform. In Fact, this bytecode is only understandable by the Java Virtual Machine(JVM).

Portable:
The WORA (Write Once Run Anywhere) concept and platform independent feature make Java portable. Now using the Java programming language, developers can yield the same result on any machine, by writing code only once. The reason behind this is JVM and bytecode. Suppose you wrote any code in Java, then that code is first converted to equivalent bytecode which is only readable by JVM.