Ehcache always returns null

Question

I'm using Ehcache 2.6.8 as part of a Spring Boot application as the second-level cache for Hibernate 4.3.11. I have a JMX MBean that allows me to inspect the contents of the cache ( here if you are interested ).

First, I use the CacheManager name to get a list of caches. That works fine. I can return the cache with cacheManager.getEhcache(cacheName) . Then I call cache.getKeys() . This works fine, the cacheName is "com.myapp.DomainObjectName" and the keys are listed as "com.myapp.DomainObjectName#1", "com.myapp.DomainObjectName#2", etc.

But then I try to access one of the objects, by calling cache.get("com.myapp.DomainObjectName#1") , using one of the keys that the cache itself told me was present. Yet, the result is always null.

Why is that? Why can I not find an object associated with a key that the cache itself, just moments before, said was present?

PS, probably not relevant, but I'm using JGroups to distribute the cache in production. However, I see the same behavior even on my laptop.

Answer 1

The fact that you can find keys indicate that there is content in your cache.

From reading your question, you are wrongly interpreting the keys as being String I believe. What JMX shows you is the toString() of the key and thus using that String as the key returns you nothing.

You need a way to use directly the object in the get(key) .