#Cacheable and initialization during startup - spring

Question

I would like to initialize all entries in cache during startup of my spring boot application (loading stuff from DB). Ideally, this is done before the application is already ready. So I implemented all loading in #PostConstruct. I remarked, that the cache is not already setup in #PostContruct and I followed some tips to do such initializations in the ApplicationReadyEvent. However, this still does not work as expected:
Even though I already call a #Cacheable Method in ApplicationReadyEvent, the second invocation re-enters the method instead of using the cache.
My Service:
#Service
public class MyService implements ApplicationListener<ApplicationReadyEvent {
#Cacheable("entry")
public List<String> getEntry() {
System.out.println("getEntry called!");
return Arrays.asList("aaa", "bbb");
}
#Override
public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {
System.out.println("*** onApplicationEvent");
getEntry();
}
}
My Caffeine CacheManager Config:
#Configuration
#EnableCaching
public class CachingConfig {
#Bean
public CacheManager cacheManager() {
List<CaffeineCache> caffeineCaches = chacheList(Arrays.asList(
"entry"
));
SimpleCacheManager simpleCacheManager = new SimpleCacheManager();
simpleCacheManager.setCaches(caffeineCaches);
System.out.println("*** #Bean CacheManager");
return simpleCacheManager;
}
private List<CaffeineCache> chacheList(List<String> cacheNames) {
return cacheNames.stream().map(s -> new CaffeineCache(s, Caffeine.newBuilder().build()))
.collect(Collectors.toList());
}
}
A simple REST endpoint using the service:
#RestController
public class MyController {
#Autowired
MyService myService;
#GetMapping("/test")
public void test()
{
System.out.println("*** GET /test");
myService.getEntry();
}
}
If I start the application and perform two GET /test, I get the following output:
INFO 20120 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 907 ms
*** #Bean CacheManager
INFO 20120 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
INFO 20120 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
INFO 20120 --- [ main] com.example.demo.DemoApplication : Started DemoApplication in 1.639 seconds (JVM running for 2.473)
*** onApplicationEvent
*** getEntry called!
INFO 20120 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
INFO 20120 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
INFO 20120 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 4 ms
*** GET /test
*** getEntry called!
*** GET /test
So why does the second invocation of MyService.getEntry (i.e. the first invocation after "Startup") enters the code again?
At the end, I need a solution, which performs the first loading before the application finished to startup - i.e. I will try ContextRefreshedEvent or again #PostConstruct (and #Autowire CacheManager to have it configured before executing #PostConstruct). But the first step would be to get this example here behave as expected.

Answer 1

Ok, stupid error: in my service, the call to getEntry() must be done over proxy object rather than directly:
#Service
public class MyService implements ApplicationListener<ApplicationReadyEvent {
#Autowired
MyService self;
#Cacheable("entry")
public List<String> getEntry() {
System.out.println("getEntry called!");
return Arrays.asList("aaa", "bbb");
}
#Override
public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {
System.out.println("*** onApplicationEvent");
self.getEntry();
}
}