How to Efficiently Convert an Integer to a Byte Array in Java?

Converting an Integer to a Byte Array in Java

To convert an integer into a byte array efficiently, consider using Java's ByteBuffer class.

ByteBuffer b = ByteBuffer.allocate(4);
b.putInt(0xAABBCCDD);
byte[] result = b.array();

This ensures that result[0] contains the highest byte (0xAA), while result[3] contains the lowest byte (0xDD).

Alternatively, you can perform the conversion manually:

public static byte[] toBytes(int i) {
  byte[] result = new byte[4];
  result[0] = (byte) (i >>> 24);
  result[1] = (byte) (i >>> 16);
  result[2] = (byte) (i >>> 8);
  result[3] = (byte) i;
  return result;
}

The ByteBuffer class offers helper methods, like int3(), for performing these operations more efficiently:

private static byte int3(int x) { return (byte) (x >>> 24); }

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