Recently I ran into an issue with Infinispan 8.2.1.Final. I have some read-through cache in invalidation mode with configured cache loader. Configuration of that cache consists of two parts. First part is the following template in XML:

<?xml version="1.0" encoding="UTF-8"?>
<infinispan xmlns="urn:infinispan:config:8.2">
    <cache-container default-cache="default">
        <transport cluster="jcache-cluster"/>
        <invalidation-cache-configuration name="user" mode="SYNC" statistics="true"/>
    </cache-container>
</infinispan>

Second part is programmatic configuration with classes and interfaces from JCache API:

new MutableConfiguration<String, User>()
    .setReadThrough(true).setStoreByValue(true)
    .setCacheLoaderFactory(FactoryBuilder.factoryOf(UserCacheLoader.class));

UserCacheLoader is extremely simple. It just creates a new instance of User every time it is called.

Everything works well until I call javax.cache.Cache.removeAll() method. It causes the following exception:

Caused by: java.lang.ClassCastException: org.infinispan.test.User cannot be cast to java.lang.String
at org.infinispan.test.UserCacheLoader.load(UserCacheLoader.java:40)
at org.infinispan.jcache.embedded.JCacheLoaderAdapter.loadKey(JCacheLoaderAdapter.java:65)
... 40 more

After some investigation I found the following code in class org.infinispan.jcache.embedded.JCacheLoaderAdapter:

@Override
public MarshalledEntry load(Object key) throws PersistenceException {
  V value = loadKey(key);

  if (value != null) {
     Duration expiry = Expiration.getExpiry(expiryPolicy, Expiration.Operation.CREATION);
     long now = ctx.getTimeService().wallClockTime(); // ms
     if (expiry == null || expiry.isEternal()) {
        return ctx.getMarshalledEntryFactory().newMarshalledEntry(value, value, null);
     } else {
        long exp = now + expiry.getTimeUnit().toMillis(expiry.getDurationAmount());
        JCacheInternalMetadata meta = new JCacheInternalMetadata(now, exp);
        return ctx.getMarshalledEntryFactory().newMarshalledEntry(value, value, meta);
     }
  }

  return null;
}

As you can see newMarshalledEntry is called using value both as a key and as a value.

Is it bug or feature? Does anyone faced with the same issue?

P.S. It seems that this issue is also actual for the latest version of Infinispan.