java spring-boot

How to find out the currently logged-in user in Spring Boot?

In this Spring Boot application there is a web service, which returns some data for a logged-in user:

public Map<String, Object> home() {
Map<String, Object> model = new HashMap<String, Object>();
model.put("id", UUID.randomUUID().toString());
model.put("content", "Hello World");
return model;

Imagine, the return value of the method depends on what user is currently logged in.

How can I find out, which user is logged in in that method?