为什么编译器声明不存在唯一的最大实例？

public class Obj<T> extends BaseModel {

    public static final String OBJECT = \"object\";

    public Obj(T object) {
        setObject(object);
    }

    public T getObject() {
        return get(OBJECT);
    }

    public void setObject(T object) {
        set(OBJECT, object);
    }
}

/** This is a 3rd party library class **/
public class BaseModel implements ModelData, Serializable {
  //...members and stuff...

  @SuppressWarnings({\"unchecked\", \"rawtypes\"})
  public <X> X get(String property) {
    X obj = null;
    if (start > -1 && end > -1) {
      Object o = map.get(property.substring(0, start));
      String p = property.substring(start + 1, end);
      if (o instanceof Object[]) {
        obj = (X) ((Object[]) o)[Integer.valueOf(p)];
      } else if (o instanceof List) {
        obj = (X) ((List) o).get(Integer.valueOf(p));
      } else if (o instanceof Map) {
        obj = (X) ((Map) o).get(p);
      }
    } else {
      obj = (X) map.get(property);
    }
    return obj;
  }
}

type parameters of <X>X cannot be determined; no unique maximal instance exists for type variable X with upper bounds T,java.lang.Object -> getObject()

@SuppressWarnings({\"unchecked\"})
public T getObject() {
    return (T) get(OBJECT); //yuck
}