Determine if a lambda expression is stateless or stateful in Java

Question

Is there a function which accepts a reference to a lambda expression and returns a boolean saying whether the lambda expression is stateless or not? How can the statefulness of

Answer 1

Here's a simple and stupid idea. Just check if your lambda has fields.

For instance, consider the following stateful lambda.

  List serialStorage = new ArrayList<>();
  Function statefulLambda =
      e -> { serialStorage.add(e); return e; };

This statefulLambda has a private final internal field arg$1 which obviously references serialStorage. So

  statefulLambda.getClass().getDeclaredFields().length > 0

could be used as indicator that lambda is stateful.

However I have no idea if this will generally work.