Suppose to have a class `Obj`:

```
class Obj {
  int field;
}

```

...and that you have a list of `Obj` instances, i.e. `List<Obj> lst`.

Now, how can I find with streams the sum of the values of the int fields `field` from the objects in list `lst` under a filtering criterion (e.g. for an object `o`, the criterion is `o.field > 10`)?