Why Java is a platform independent language

 Java is a platform-independent language. First it we write a source code. Source code is something whose file extension is .java. The compiler compiles the program checks for an error and won’t let you compile till the code is error-free compiler compiles the source code into byte code any this byte code is platform-independent. Any device which is capable of running this byte code will translate this byte code into their own code which they can understand very easily. That’s why we call java is a platform-independent language. In fact this is a very popular interview question.

 

So basically source file contains a class. The class contains a method. Methods contain a set of statements.

 

In simple words, we can say that JVM is a device that provides a run time environment to java byte code which was produced by the compiler after processing source code.

 

When JVM starts running we look for a class that contains the main method. And JVM starts executing everything which is present in the main method of the class. Every java application has at least one main method.

 

The main method looks like the below example.

 

public static void main(String[] args){

 

}

 

Let's discuss keywords of the main class one by one.

public - is an access modifier(everyone can see this)

static - can be instantiated without creating an object.

void - there is no return type of this method.

String[] - arguments which are passed to this method will be an array of strings named args.

 

Everything in bracket {} will be executed by the compiler.

 

Difference between System.out.println and System.out.print.

println print gives a line break after printing while print doesn’t give a line break after printing.

 

A java class consists of instance variables and methods.

1. Instance variables are simply variables defined outside the method.

2. Method is a simple to set of statements.

 

Class -  Class is basically a structure. This is a generic form.For example human skeleton. Every human hair colour, language. nationality,

 

Objects - An object is a specific form. For example colour of hair can be brown, black, red or white, there are many languages in the world. It can be English, Hindi etc. The nationality of a person can be different.

 

How to create an object

 

Class Human{

 

                Private String hairColor;

                Private String language;

                Private String nationality;

 

                Public Human(String hairColor1, String language1, String nationality1){

                this.hairColor = hairColor1;

this.language= language1;

this.nationality= nationality1;

}

 

void printTest(){

                System.out.println(“Haircolor: ”+ hairColor + “language”+language);

}

}

 

Class test{

                Public static void main(String[] args){

                Human human1 = new Human();     // object created

               

 

}

}