Fixing javadoc issue

Signed-off-by: Sagar Upadhyaya <sagar.upadhyaya.121@gmail.com>

server/src/main/java/org/opensearch/common/lucene/index/OpenSearchDirectoryReader.java

@@ -79,6 +79,10 @@ public DelegatingCacheHelper getDelegatingCacheHelper() {
         return this.delegatingCacheHelper;
     }
 
+    /**
+     * Wraps existing IndexReader cache helper which internally provides a way to wrap CacheKey.
+     * @opensearch.internal
+     */
     public class DelegatingCacheHelper implements CacheHelper {
         CacheHelper cacheHelper;
         DelegatingCacheKey serializableCacheKey;
@@ -103,6 +107,10 @@ public void addClosedListener(ClosedListener listener) {
         }
     }
 
+    /**
+     *  Wraps internal IndexReader.CacheKey and attaches a uniqueId to it which can be eventually be used instead of
+     *  object itself for serialization purposes.
+     */
     public class DelegatingCacheKey {
         CacheKey cacheKey;
         private final UUID uniqueId;

server/src/main/java/org/opensearch/indices/IndicesRequestCache.java

@@ -198,7 +198,7 @@ void invalidate(CacheEntity cacheEntity, DirectoryReader reader, BytesReference
      *
      * @opensearch.internal
      */
-    protected static class Loader implements CacheLoader<Key, BytesReference> {
+    private static class Loader implements CacheLoader<Key, BytesReference> {
 
         private final CacheEntity entity;
         private final CheckedSupplier<BytesReference, IOException> loader;