Duplicating byte array multiple times

Question

I have this code that duplicates a byte array 5 times.

class Multiple {
 public static void main(String[] args) {
 byte[] result = new byte[] {0x41,0x42,0x43,0x44};
 int len = result.length;
 byte[] multipled = new byte[len*5];
 for (int i = 0; i < 5; i++) {
 for (int j = 0; j < len; j++) {
 multipled[i*len + j] = result[j];
 }
 } 
 System.out.println(new String(multipled));
 System.out.println(new String(result));
 }
}

Example:

ABCDABCDABCDABCDABCD
ABCD

The code uses multiple loops and assignment, can it be better or shorter?

Answer 1

It can be made shorter:

public static void main(String[] args) {
 byte[] result = new byte[] {0x41, 0x42, 0x43, 0x44};
 byte[] multipled = new byte[result.length * 5];
 for (int i = 0; i < multipled.length; i++)
 multipled[i] = result[i % result.length];
 ...
}

• Dawood ibn Kareem: @NexusDuck using new String in this case is necessary, because an array's toString just prints the object address, not the content.
• NexusDuck: @DavidWallace I had no idea. Disregard my comment then

Answer 2

This operation is worth defining as a function for clarity and reuse.

To copy an array, use System.arraycopy().

public static byte[] repeat(byte[] array, int times) {
 byte[] repeated = new byte[times * array.length];
 for (int dest = 0; dest < repeated.length; dest += array.length) {
 System.arraycopy(array, 0, repeated, dest, array.length);
 }
 return repeated;
}