caching - Spring cache @Cacheable method ignored when called from within the same class

Question

I'm trying to call a @Cacheable method from within the same class:

@Cacheable(value = "defaultCache", key = "#id")
public Person findPerson(int id) {
   return getSession().getPerson(id);
} 

public List<Person> findPersons(int[] ids) {
   List<Person> list = new ArrayList<Person>();
   for (int id : ids) {
      list.add(findPerson(id));
   }
   return list;
}

and hoping that the results from findPersons are cached as well, but the @Cacheable annotation is ignored, and findPerson method got executed everytime.

Am I doing something wrong here, or this is intended?

Answer 1

This is because of the way proxies are created for handling caching, transaction related functionality in Spring. This is a very good reference of how Spring handles it - Transactions, Caching and AOP: understanding proxy usage in Spring

In short, a self call bypasses the dynamic proxy and any cross cutting concern like caching, transaction etc which is part of the dynamic proxies logic is also bypassed.

The fix is to use AspectJ compile time or load time weaving.