code: public Object getObject(final JsiiObjectRef objRef) {
          Object obj = this.objects.get(objRef.getObjId());
          if (obj == null) {
              throw new JsiiException("Cannot find jsii object: " + objRef.getObjId());
          }
          return obj;
      }
docs: Gets an object by reference. Throws if the object cannot be found.
  
  @param objRef The object reference
  @return a JsiiObject
  @throws JsiiException If the object is not found.