Java 8 lambda Void argument

Question

Let\'s say I have the following functional interface in Java 8:

interface Action {
   U execute(T t);
}

And for some cases I ne

Answer 1

Use Supplier if it takes nothing, but returns something.

Use Consumer if it takes something, but returns nothing.

Use Callable if it returns a result and might throw (most akin to Thunk in general CS terms).

Use Runnable if it does neither and cannot throw.