Shallow copy, bad idea

gistfile1.java

static Object shallowCopy(Object obj) {
  long size = sizeOf(obj);
  long start = toAddress(obj);
  long address = getUnsafe().allocateMemory(size);
  getUnsafe().copyMemory(start, address, size);
  return fromAddress(address);
}

static long toAddress(Object obj) {
  Object[] array = new Object[] {obj};
  long baseOffset = getUnsafe().arrayBaseOffset(Object[].class);
  return normalize(getUnsafe().getInt(array, baseOffset));
}

static Object fromAddress(long address) {
  Object[] array = new Object[] {null};
  long baseOffset = getUnsafe().arrayBaseOffset(Object[].class);
  getUnsafe().putLong(array, baseOffset, address);
  return array[0];
}

static long sizeOf(Object object){
  return getUnsafe().getAddress(
    normalize(getUnsafe().getInt(object, 4L)) + 12L);
}

static long normalize(int value) {
  if(value >= 0) return value;
  return (~0L >>> 32) & value;
}