How can I convert a byte array into a double and back?

Question

For converting a byte array to a double I found this:

//convert 8 byte array to double int start=0;//??? int i = 0;     int len = 8;     int cnt = 0;     byte[] tmp = new byte[len];     for (i = start; i < (start + len); i++) {         tmp[cnt] = arr[i];         //System.out.println(java.lang.Byte.toString(arr[i]) + " " + i);         cnt++;     }     long accum = 0;     i = 0;     for ( int shiftBy = 0; shiftBy < 64; shiftBy += 8 ) {         accum |= ( (long)( tmp[i] & 0xff ) ) << shiftBy;         i++;     }          return Double.longBitsToDouble(accum); 

But I could not find anything which would convert a double into a byte array.

Answer 1

Or even simpler,

import java.nio.ByteBuffer;  public static byte[] toByteArray(double value) {     byte[] bytes = new byte[8];     ByteBuffer.wrap(bytes).putDouble(value);     return bytes; }  public static double toDouble(byte[] bytes) {     return ByteBuffer.wrap(bytes).getDouble(); }