public static byte [] head(final byte [] a, final int length) {
    if (a.length < length) {
      return null;
    }
    byte [] result = new byte[length];
    System.arraycopy(a, 0, result, 0, length);
    return result;
  }
public static byte [ ] head ( final byte [ ] a , final int length ) { if ( a . length < length ) { return null ; } byte [ ] result = new byte [ length ] ; System . arraycopy ( a , 0 , result , 0 , length ) ; return result ; }
Returns first <code>length</code> bytes from byte array.
@param a array
@param length amount of bytes to grab
@return First <code>length</code> bytes from <code>a</code>