I wrote the following code as an example to show how to
 dynamically create and fill an arrays whose arbitrary
 extensions and arbitrary dimension is only known at run-time.

 Here it is suppossed to have 3 dimensions with extensions 4,
 5, and 6, respectively.

public class Main
{
 public static int[] cdr( final int[] list )
 { return java.util.Arrays.copyOfRange( list, 1, list.length ); }

 public static java.lang.Object build( final int ... extensions )
 { final java.lang.Object array = java.lang.reflect.Array.newInstance
   ( java.lang.Integer.TYPE, extensions );  
   for( int i = 0; i < extensions[ 0 ]; ++i )if( extensions.length > 1 )
   java.lang.reflect.Array.set( array, i, build( cdr( extensions )));
   else java.lang.reflect.Array.setInt(( int[] )array, i, i );
   return array; }

 public static void print( final java.lang.Object array )
 { for( int i = 0; i < java.lang.reflect.Array.getLength( array ); ++i )
   if( array.getClass().getName().startsWith( "[[" ))
   print( java.lang.reflect.Array.get( array, i )); else
   java.lang.System.out.print( java.lang.reflect.Array.getInt( array, i )); }
   
 public static void main( final java.lang.String[] args )
 { print( build( 4, 5, 6 )); }}
 
012345012345012345012345012345012345012345012345012345012345012345012345012345012345012345012345012345012345012345012345

for arbitrary dimension i mean a class wich at run time can be seen, as
a[]
or a[][]
or a[][][]
or a[][][][]

Becouse I have some algs that are invariant, theoretically on this kind
of structure but don't wont to write a version of them for every
option..
thanks

If your Google broken? Already the first hit from googleing
http://www.google.de/search?q=Java+math+matrix looks interesting.

/Thomas