Cache.get(key, type) explicitly defines an IllegalStateException in case of a type mismatch

Issue: SPR-12145
(cherry picked from commit 2f93759)

Author: jhoeller

spring-context/src/main/java/org/springframework/cache/Cache.java

@@ -66,6 +66,8 @@ public interface Cache {
 	 * @return the value to which this cache maps the specified key
 	 * (which may be {@code null} itself), or also {@code null} if
 	 * the cache contains no mapping for this key
+	 * @throws IllegalStateException if a cache entry has been found
+	 * but failed to match the specified type
 	 * @see #get(Object)
 	 * @since 4.0
 	 */