Is there any way I can get the underlying key and value type definition of the cache that is created by some other code? At this point of time I only know the cache name. I don't have any other information about how the cache was created. The cache is here Jcache.
javax.cache.Cache cache = cachingService.getCache(cacheName);
Here it is casted to Object,Object.But I want to know the actual key type and value type.
Once you have a Cache available, you can find out the key/value types with which it was configured by inspecting its Configuration:
// assuming you already have a Cache object available:
javax.cache.configuration.Configuration cacheConfig = cache.getConfiguration(Configuration.class);
Class keyType = cacheConfig.getKeyType();
Class valueType = cacheConfig.getValueType();
Now, in order to obtain the Cache itself when using JCache 1.0 if you are not aware of its configured key/value types options, your only option is to use cacheManager.getCache(name). However according to JCache 1.0 this will only work if the Cache was not configured with any specific types (ie Object.class is the key and value type), otherwise will fail with IllegalArgumentException (see [1]). Essentially you are caught in a vicious circle.
This behavior has been updated in JCache 1.1 (see related issue in [2]): now cacheManager.getCache(name) specification is relaxed and may return the Cache if one exists by the given name, regardless of configured key/value types. The only catch right now is that JCache 1.1 was released just a couple of days ago (December 16th, 2017, see [3]), so most probably implementations are not yet updated to allow this behavior.
[2] https://github.com/jsr107/jsr107spec/issues/340#issuecomment-254070714
[3] http://search.maven.org/#artifactdetails%7Cjavax.cache%7Ccache-api%7C1.1.0%7Cjar
