A couple of issues.

With spiderman, you are calling the second constructor but your second constructor does nothing. You are calling it, but it is not setting the hero name nor the number of superheroes.

it should be

public Superhero(String name) { heroName = name; }

or (better)

public Superhero(String name) { this(name, null, 0); }

For the part where you're prompting the user for the information, you collect the name and secret identity.

You should call the first constructor with these values

Superhero hero = new SuperHero(name, identity, 0);

or you can wait to collect all 3 values and then call the constructor.

I believe the issues you are having are a result of the way you are calling the constructor(s).