code: private void readObject(java.io.ObjectInputStream s)
          throws java.io.IOException, ClassNotFoundException {
          // Read in all fields
          s.defaultReadObject();
          // validate possibly bad fields
          if (intVal == null) {
              String message = "BigDecimal: null intVal in stream";
              throw new java.io.StreamCorruptedException(message);
          // [all values of scale are now allowed]
          }
          UnsafeHolder.setIntCompactVolatile(this, compactValFor(intVal));
      }
docs: Reconstitute the {@code BigDecimal} instance from a stream (that is,
  deserialize it).
  
  @param s the stream being read.