Mockito ArgumentMatcher lambda function with parameter not recognizing method

Question

I'm trying to learn Mockito framework and implementing some mocks. Currently, I want to use ArgumentMatcher to check if the passed object matches. I saw that in the past this was possible by creating a new class that extends ArgumentMatcher . However, now it's possible to use Java 8 lambda functions . This is how I'm trying to implement it:

private ArgumentMatcher<User> matchUser(User user) {
    return u -> u != null && user.getId() == u.getId();
}

IntelliJ is giving me an error, as it's telling that u doesn't have the getId method. Should't u type be inferred to User ?

Answer 1

You have Mockito version 1.x, where ArgumentMatcher is an abstract class. As of Mockito 2.x, they changed it to be an interface , allowing to use lambdas.

The source code of ArgumentMatcher shows that:

• Branch release-2.x on GitHub
• Branch release-1.x on GitHub

If you fix your dependencies to a more recent version of Mockito, it'll work.