Question

what is constructor in Java? How it is important in Java?

Answer 1

A constructor in Java is a method that can have parameters, in which its name is the same as the name of the class.
Example1 :

class Ravi2 {
public Ravi2() {
// Your code here...
}
}

It's used to instantiate the class (create an object), and to initialize the parameters if it's necessary.
Instantiate Example1 :

Ravi2 raviObject = new Ravi2();

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Consider now this Example2.
Example2 :

class Ravi2 {
public Ravi2(String name) {
System.out.println(name);
}
}
Instantiate Example2 :

Ravi2 raviObject = new Ravi2("Ravi");
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Good luck.

Answer 2

thnx dear good response.....! now some confusion about instance Variables which are related to constructors....

Answer 3

plz ...tell me about executing process when we call the constructor from Class to the main method for execute?

Answer 4

If you are asking about how a program gets executed, then you should learn the Compilation, which we can summarize it as "The transformation of your code from a high level to the machine code, so your processor can understand it and execute it". To know how this happen, you should study compilation.