a static method call in a constructor?

[Vishwanath Krishnamurthi]

Hi, good people,

In the following code, I don't understand why only a static method and not an instance method can be used in Animal() constructor. K&B says

"an instance method cannot be invoked until after the superclass constructor has run."

Can you please explain this statement with respect to this code...

Also please show me the place where a super() is implicitly inserted...

public class Animal
  {
    String name;
    Animal(String name)
      {
        this.name=name;
      }
 
    Animal()
      {
        this(makeRandomName());
      }
 
    static String makeRandomName()
      {  
        String name;
        //code to generate a random name
        return name;
      }
 
    public static void main(String [] args)
      {
        Animal a=new Animal();
        //more code
      } 
  }

Thanks.
[ June 30, 2007: Message edited by: Vishwa nath.K ]

[Manfred Klug]

Hi Vishwa,

public class Animal {
    String name;
 
    Animal(String name) {
        [B]super();[/B]
        this.name = name;
    }
 
    Animal() {
        this(makeRandomName());
    }
 
    static String makeRandomName() {
        String name;
        // code to generate a random name
        return name;
    }
 
    public static void main(String[] args) {
        Animal a = new Animal();
        // more code
    }
}

[Javier Corral]

In a constructor if you call this() the compiler won't implicity insert super(). In the constructor Animal(), there is a this() called, and for this reason the compiler don't insert super(), whereas in constructor Animal(String name) the compiler implicity adds super() (at the first line).

If you take a look at the order of execution, you'll see that, first of all Animal() is called, then Animal() calls this(makeRandomName()) but we still don't arrived to super() and as k&B says makeRandomName() has to be static because superclass is still not constructed.