Creating new entity plus association not working

Question

I am having two entities AppUser and UserGroup. They have a @ManyToMany relationship.

I am currently trying to create

Answer 1

try

@Column(name = "app_user_id")
@ManyToMany(fetch = FetchType.LAZY, mappedBy = "groups",cascade = CascadeType.ALL)
private Set<AppUser> users;

finally pass list of users

{
  "name": "Group 1", 
  "users": ["http://localhost:8080/users/1"]
}

for Cannot deserialize instance of java.util.Set error it expect a list of users not instans of single user