code: public void setWrappedObject(Object obj) {
          if (obj == null) {
              throw new IllegalArgumentException("Cannot warp a 'null' object.");
          }
  
          this.object = obj;
          this.bean = Bean.forClass(obj.getClass());
      }
docs: Changes, at any time, the wrapped object with a new object.
  
  @param obj the new object to wrap
  @throws IllegalArgumentException if the obj parameter is {@code null}