I had same problem and randomly did such things as (several times):
1) Project->Clean…,
2) close and open Eclipse again,
3) Run As…
And it started to work again, without changing configuration.
I had same problem and randomly did such things as (several times):
1) Project->Clean…,
2) close and open Eclipse again,
3) Run As…
And it started to work again, without changing configuration.