Confused why getting a User from Repository fixed "failed to lazily initialize a collection of role" compared to using SecurityContextHolder - spring

Question

My goal was to pass a List of Businesses to the model from the controller to display it in a view and I have succeeded, but have a bit of confusion.
When I initially tried using:
public User getCurrentAuthenticatedUser() {
UserDetailsImpl user = (UserDetailsImpl) SecurityContextHolder.getContext().getAuthentication().getPrincipal();
return user.getUser();
}
#GetMapping("")
public String list(Model model) {
model.addAttribute("businesses", userService.getCurrentAuthenticatedUser().getBusinesses());
return "business/list";
}
I got this error: "failed to lazily initialize a collection of role: com.xyz.User.businesses could not initialize proxy - no Session"
Then I tried:
#GetMapping("")
public String list(Model model) {
int userId = userService.getCurrentAuthenticatedUser().getId();
User user = userService.getById(userId); // gets User using Spring Data JPA UserRepository
List<Business> businesses = user.getBusinesses();
model.addAttribute("businesses", businesses);
return "business/list";
}
And this worked perfectly fine.
What was the issue using the first method. It seemed more simple rather than calling a User from the UserRepository. I've seen some posts that say you should use EAGER fetching, but that's just seems like a bandaid solution.
From the beginner's understanding: Since fetch type is LAZY the businesses don't exist yet in the User but are fetched on demand later on so there shouldn't be an issue.
Edit: After more thought I remembered that with basic Hibernate you would have to create Transactions and commit transactions. I'm assuming that User is not within a Transaction that's why I can't get businesses using the 1st method.
What would be a better solution to fetch the current Authenticated user? And that user's attributes such as a list of businesses.
Model Classes:
Business:
#Entity
#Table(name = "businesses")
public class Business {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String description;
private LocalDate date;
#ManyToOne(cascade={CascadeType.MERGE})
#JoinColumn(name="user_id")
private User user;
public Business() {
}
public Business(String name, String description, LocalDate date, User user) {
...
}
public Business(Long id, String name, String description, LocalDate date, User user) {
...
}
... getters/setters
}
USER:
#Entity
#Table(name = "users")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private String username;
private String password;
private boolean enabled;
#ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
#JoinTable( name = "users_roles",
joinColumns = #JoinColumn(name = "user_id"),
inverseJoinColumns = #JoinColumn(name = "role_id"))
private Set<Role> roles = new HashSet<>();
#OneToMany(fetch = FetchType.LAZY, mappedBy="user", cascade={CascadeType.MERGE})
private List<Business> businesses;
... getters/setters
}