That says nothing about all the numbers having to be random.
Also, I'm not trying to be mean, but could you please use less abbreviations like "u"? It makes your post harder to read. Thanks.
Here's what you could do if they have to be random, I don't know Java very well though so it might not compile
void fill_array(int[] array)
{
do
{
for(int i=0;i<6;i++)
{
array[i] = Math.random()*45;
}
}while(!NoneTheSame(array));
}