Looks like concat should do the trick, though you'll obviously have to create a new array and then concatenate each array to this in turn.

You might also want to look at ArrayList.

The fastest way, if the lengths of the arrays are all fixed, is just to loop:
Code:

for (int i = 0; i < 4; i++)
{
   target[i] = o1[i];
   target[i + 4] = o2[i];
   target[i + 8] = o3[i];
} 

i<4 means the loop will run 4 times where i = 0,1,2,3
Remember that arrays start counting at zero so this equates perfectly to the four indices in your arrays.  'target[]' is a new array to which you want to copy the values from the other arrays.  So:

for (int i = 0; i < 4; i++) {
  // target [0],[1],[2],[3] will be populated with the values from object one array
  target[i] = o1[i];
 // target [4],[5],[6],[7] will be populated with values from object two array
  target[i + 4] = o2[i];
  // target [8],[9],[10],[11] will be populated with values from object three array
  target[i + 8] = o3[i];
}

That leaves you with the target array containing all the values from the three separate arrays in the order you want them

hello phyllo, your example works fine when i have one dimensional array, but what about if my array that stores that objects  is 2 dimensional?

ive tried something like this without luck, any idea of what im doing wrong?

Code:

int al = objects[0][0].coords.length;
for (int i = 0 ; i < al ; i++)
{
for (int j = 0; j<objects.length ; j ++)
{
for (int k = 0 ; k < objects.length ; k ++)
{
target[i + j + k * al ] = objects[j][k].coords[i];
}}}