Modifying local variable from inside lambda

Question

Modifying a local variable in forEach gives a compile error:

Normal

    int ordinal = 0;
    for (Example s : list) {
          


        

Answer 1

To have a more general solution, you can write a generic Wrapper class:

public static class Wrapper {
    public T obj;
    public Wrapper(T obj) { this.obj = obj; }
}
...
Wrapper w = new Wrapper<>(0);
this.forEach(s -> {
    s.setOrdinal(w.obj);
    w.obj++;
});

(this is a variant of the solution given by Almir Campos).

In the specific case this is not a good solution, as Integer is worse than int for your purpose, anyway this solution is more general I think.