Object reference array assignment

[Shiva Mohan]

    
class A11 {public String toString() {return "A11";}}
class Doubt {
  public static void main(String[] arg) {
    A11[]     a1 = new A11[1];         // 1
    A11[][]   a2 = new A11[2][];       // 2
    A11[][][] a3 = new A11[3][][];     // 3
    a1[0] = new A11();                 // 4
    a2[0] = a2[1] = a1;                // 5
    a3[0] = a3[1] = a3[2] = a2;        // 6
    a3[0][1]=a2;                       //7------------compile error
    System.out.print(a3[2][1][0]);     // 8
}}

I don't get this reference assignment.
My ananlysis about line 5 is,a2[0] and a2[1] are one dimensinal arrays and a1 reference is also one dimensional array.so assignation is valid
My analysis about line 6,a3[0],a3[1],a3[2] are one dimensional array and a2 reference is two dimensional array.i thought it would be invalid.but this one compiles fine .How?Please explain.
My understanding about line 7,a3[0][1] is two-dimensional array and a2 reference is also two-dimensional array.so ithought it would valid.but this statement produce compilee error.Please explain
[ September 18, 2006: Message edited by: Shiva Mohan ]

[Keith Lynn]

a3[0][1] is a 1-dimensional array.

[Shiva Mohan]

Thanks for the reply Keith. In declaration of a3 is an three-dimensional array.Right?
In the statement a3[0][1]=a2;here a3 is two-dimensional array.How come a3 is one-dimensional.Please explain

[Rahuldf sharmadf]

it is one dimensional array

[Shiva Mohan]

At which line,a3 three-dimensional array is changed to one-dimensional.Please explain if possible?

[Henry Wong]

Originally posted by Shiva Mohan:
Thanks for the reply Keith. In declaration of a3 is an three-dimensional array.Right?
In the statement a3[0][1]=a2;here a3 is two-dimensional array.How come a3 is one-dimensional.Please explain

a3 is "three-dimensional". a2 is "two-dimension". And a3[0][1] is one dimensional.

Henry

PS... I place the number of arrays in quotes, because technically, Java supports arrays of arrays -- not multidimensional arrays. (but for this debate, it's an okay interpretation.)

[Meena R. Krishnan]

a3 is a 3-d array of size 3.(line 3 )

a3[0], a3[1],a3[2] each in turn is a 2-d array and each of size 2. (line 6) - since the value of a2 is being assigned to these.

a3[0][0],a3[0][1],a3[1][0],a3[1][1] each in turn is a 1-d array of size 1. ( each carrying the reference to A11 )