Java: How can a constructor return a value? [duplicate]

Answer 1

What you've defined isn't actually a constructor, but a method called Const. If you changed your code to something like this, it would work:

Const c = new Const();
System.out.println( c.Const( "Hello!" ) );

If no specific constructor is explicitly defined, the compiler automatically creates a no-argument constructor.

Answer 2

A constructor can't have a return value like a "normal" function. It is called when an istance of the class in question is created. It is used to perform the initialization of that instance.

Answer 3

Many great answers already. I would just like to add that, if you want to get some return code separate from the object itself as a result of invoking a constructor, you can wrap the constructor in a factory method which, upon creation, could for example do some data validation within the constructed object and return a boolean depending on the outcome.

Answer 4

Actually Constructor in a java class can't return a value it must be in the following form

public class Test {
 public Test(/*here the params*/) {
   //this is a constructor
   //just make some operations when you want to create an object of this class
 }
}

check these links http://leepoint.net/notes-java/oop/constructors/constructor.html http://java.sun.com/docs/books/tutorial/java/javaOO/constructors.html

Answer 5

Constructors cannot return a value; they return the constructed object, so to speak.

You get an error because the compiler is looking for a constructor that takes a string as its argument. Since you did not declare a constructor the only constructor available is the default constructor that does not take any argument.

Why do I say you did not declare a constructor? Because as soon as you declare a return value/type for your method it is not a constructor anymore but a regular method.

From the Java Documentation:

A class contains constructors that are invoked to create objects from the class blueprint. Constructor declarations look like method declarations—except that they use the name of the class and have no return type.

If you elaborate what you are trying to achieve someone might be able to tell you how you can get to that goal.