getValue not working on SAMLUserDetailsServiceImpl

Question

I'm trying to implement SAML SSO on my project but there's a weird problem, the method getValue() is not working, it just says "Cannot resolve method 'getValue()'". Right on credential.getNameID().getValue() the getValue gets red and it shows that message, I've searched everywhere but found no answer

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import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.security.saml.SAMLCredential;
import org.springframework.security.saml.userdetails.SAMLUserDetailsService;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class SAMLUserDetailsServiceImpl implements SAMLUserDetailsService {

    // Logger
    private static final Logger LOG = LoggerFactory.getLogger(SAMLUserDetailsServiceImpl.class);

    public Object loadUserBySAML(SAMLCredential credential)
            throws UsernameNotFoundException {

        // The method is supposed to identify local account of user referenced by
        // data in the SAML assertion and return UserDetails object describing the user.

        //PROBLEM RIGHT HERE
        String userID = credential.getNameID().getValue();

        LOG.info(userID + " is logged in");
        List<GrantedAuthority> authorities = new ArrayList<GrantedAuthority>();
        GrantedAuthority authority = new SimpleGrantedAuthority("ROLE_USER");
        authorities.add(authority);

        // In a real scenario, this implementation has to locate user in a arbitrary
        // dataStore based on information present in the SAMLCredential and
        // returns such a date in a form of application specific UserDetails object.
        return new User(userID, "<abc123>", true, true, true, true, authorities);
    }

}

`

There's no much to try