How can I throw CHECKED exceptions from inside Java 8 streams?

Question

How can I throw CHECKED exceptions from inside Java 8 streams/lambdas?

In other words, I want to make code like this compile:

public List

        

Answer 1

You cannot.

However, you may want to have a look at one of my projects which allows you to more easily manipulate such "throwing lambdas".

In your case, you would be able to do that:

import static com.github.fge.lambdas.functions.Functions.wrap;

final ThrowingFunction> f = wrap(Class::forName);

List classes =
    Stream.of("java.lang.Object", "java.lang.Integer", "java.lang.String")
          .map(f.orThrow(MyException.class))
          .collect(Collectors.toList());

and catch MyException.

That is one example. Another example is that you could .orReturn() some default value.

Note that this is STILL a work in progress, more is to come. Better names, more features etc.