<java>demande conseil sur ce prg

bonjour
j'ai essayé ce prg suivant

package Essaie;
public class Cube1
{
int length;
int breadth;
int height;

public int getVolume()
{
return (length*breadth*height);
}
Cube1()
{
this(10,10);
System.out.println("Finished with default constructor");
}
Cube1(int l,int b)
{
this(l,b,10);
System.out.println("Finished with parameterized constructor having 2 params");
}
Cube1(int l,int b,int h)
{
length=10;
breadth=10;
height=10;
System.out.println("Finished with parameterized constructor having 3 params");
}
}
package Essaie;
public class Rectangle
{
public static void main(String[]args)
{
Cube1 cubeObj1,cubeObj2;
cubeObj1=new Cube1();
cubeObj2=new Cube1(10,20,30);

System.out.println("volume of Cube1 is:"+cubeObj1.getVolume());
System.out.println("volume of Cube2 is:"+cubeObj2.getVolume());
}
}

le output ce ce prg est le suivant
Finished with parameterized constructor having 3 params
Finished with parameterized constructor having 2 params
Finished with default constructor
Finished with parameterized constructor having 3 params
volume of Cube1 is:1000
volume of Cube2 is:1000

mes questions sont suivantes:
1.normalement volume of cube2 is:6000; pourquoi j'ai 1000,où je puis faire erreur?
2.pourquoi output est désordonné au lieu de avoir comme ceci
Finished with default constructor
Finished with parameterized constructor having 2 params
Finished with parameterized constructor having 3 params
3.et pourquoi j'ai deux fois la ligne suivante?
Finished with parameterized constructor having 3 params