What is mean constructor in java?

Answer 1

A parameterized constructor in java is just a constructor which take some kind of parameter (variable) when is invoked. For example.

class MyClass {

//this is a normal constructor

public MyClass(){

//do something

}

//this is a parameterized constructor

public MyClass(int var){

//do something

}

//this is another parameterized constructor

public MyClass(String var, Integer var2){

//do something

}

}

Answer 2

It is also called the default constructor. It is the constructor that the java compiler places in every class where the programmer has not explicitly coded a constructor.

Ex:

public class Car {

...

//lots of code but no constructor

}

If a person writes a class as above, then the compiler places this code in the compiled version of the file.

public Car() {

super();

}

This is called the non-parameterized or default constructor

Answer 3

A constructor is a method that is called whenever a class is created. It does the business of preparing the class (itself) so that it may do its job when called upon. It may set internal variables according to configuration information, it may create child objects with which it must interact, it may establish a remote connection, etc. In short, it does what needs to be done before the program may interact with it.