constructor

[abalfazl hossein]

   

public class Superclass {

    public int i;
    public void Superclass(int j) {
        i=j;
        System.out.println(i);
    }
    public void printMethod() {
        System.out.println("Printed in Superclass.");
    }
public class Subclass extends Superclass {

    
    public void Subclass(int k){
        super(k);
    }

    public void printMethod() { //overrides printMethod in Superclass
        super.printMethod();
        System.out.println("Printed in Subclass");
    }
}
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {

    Subclass s = new Subclass(4);
    s.printMethod();
    }

 

When I compile, this error shows:

Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - cannot find symbol
symbol : constructor Subclass(int)
location: class superclass.Subclass
at superclass.Main.main(Main.java:19)
Java Result: 1


Please guide me

[Joanne Neal]

You don't have constructors in either of your classes that take an int as a parameter.
You do have methods in both classes with the same name as the class.

[Raza Mohd]

Constructors have no return type.

[abalfazl hossein]

Becuase of void.Understood!

Constructor is a method by the name of class,without any return type,Right?

[Raza Mohd]

hi,

Method must have a return type. then how can you say constructor a method?

[Rob Spoor]

abalfazl hossein wrote:When I compile, this error shows:

Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - cannot find symbol
symbol : constructor Subclass(int)
location: class superclass.Subclass
at superclass.Main.main(Main.java:19)
Java Result: 1

Impossible. When you compile your code you can never get an exception. You probably use an IDE (Eclipse, Netbeans, etc) that allows you to run classes even if they do not compile. Always fix any compiler errors before you run the class.

[Gary Ba]

This might help -> constructors

[Jesper de Jong]

abalfazl hossein wrote:Constructor is a method by the name of class,without any return type,Right?

A constructor is technically not really a method, even though it somewhat looks like a method. A constructor is a special block of code that is called when you create a new object, to initialize the new object.

[Lee Kian Giap]

a better said is void also a return type which return nothing

so in your code , you doesn't declare any constructor (except the default non-arg constructor that auto generated by compiler), what you have declare is all METHOD ...
so when you try to instantiate a Subclass object , " Subclass s = new Subclass(4); " , the compiler can't find that constructor.