In fact, the trouble comes from LinkedIn. However, there is a way to dodge the problem using the linkedin.restOperations()
supplied by Spring social.
Here is how I proceeded :
String url = String.format("https://api.linkedin.com/v1/people/id=%s:(summary)", connection.getId());
LinkedInProfile summaryProfile = source.restOperations().getForObject(url, LinkedInProfile.class);
String summary = summaryProfile.getSummary();
This way, the summary is well recovered, at the cost of an extra REST query. Another downside of this method is the fact that search operations are limited to 100 queries a day per user.