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Java Java Objects Creating the MVP Getting Started

Posted by Mark Chesney
Mark Chesney
11,747 Points

Is a constructor always public?

Is a constructor always public?

Thank you :)

1 Answer

Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

It's uncommon, but possible to to have private (or protected) constructors. But a private constructor can only be called from within the class itself, so a new instance could only be created by a class method.

This might be used by a singleton class, to insure that only one instance is ever created.

Mark Chesney
Mark Chesney
11,747 Points

so I know by convention the constructor name matches the class, but had that NOT been the case, then would it be this?

class object = new constructor();
// example
Car bmw = new Car();

What's a singleton class? I'm gonna need the Java for newbies answer 🙂

Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

The fancy-sounding name "singleton" just means that the class is designed to have only one instance. Restricting the constructor to a class method allows you to write code to guarantee a second instance is not created.