tt-user.java

@Entity
public class User implements Serializable, UserDetails {
	
	// Spring Security props
	private transient Collection<GrantedAuthority> authorities;
	
	public void setUserAuthorities(Collection<Role> roles) {
		List<GrantedAuthority> listOfAuthorities = new ArrayList<GrantedAuthority>();
		for (Role role : roles) {
			listOfAuthorities.add(new GrantedAuthorityImpl(role.getRole()));
		}
		this.authorities = (Collection<GrantedAuthority>) listOfAuthorities;
	}
.....
}