Java – Lambda Expressions – You cannot set a lambda parameter as an argument to a method

I’m trying to use lambda expressions on Android using retrolambda. In the following code, I need to add a listener as an interface:

 public interface LoginUserInterface {

void onLoginSuccess(LoginResponseEntity login);

void onLoginFail(ServerResponse sr);
    }

Code

 private void makeLoginRequest(LoginRequestEntity loginRequestEntity) {
        new LoginUserService(loginRequestEntity)
                .setListener(
                        login -> loginSuccess(login),
                        sr -> loginFail(sr))
                .execute();
    }

private void loginSuccess(LoginResponseEntity login) {
         TODO loginSuccess
    }

private void loginFail(ServerResponse sr) {
        TODO loginFail
    }

However, Android Studio marks the red loginSuccess(login) and loginFail(sr) as errors
and displays the messages “LoginResponseEntity cannot be applied to” and “ServerResponse cannot be applied to”

So I can’t set the lambda parameter “login” to the parameter of the method loginSuccess(login).
Please help me understand what’s wrong with this expression.

You can only combine lambda with >Functional interfaces together. This means that your interface must specify only one method.

The best way to keep this in mind (simply – to be able to use lambdas instead of anonymous classes) is to add @FunctionalInterface annotations to your interface.

@FunctionalInterface
public interface LoginUserInterface {
    LoginResult login(...)
}

The value of LoginResult is then dispatched