Polishing.

Handle warnings. Remove redundant code in DefaultReactiveEntityCallbacks.

Original pull request: #3053
See #3055

src/main/java/org/springframework/data/mapping/callback/DefaultEntityCallbacks.java

@@ -63,6 +63,7 @@ class DefaultEntityCallbacks implements EntityCallbacks {
 	}
 
 	@Override
+	@SuppressWarnings({ "unchecked", "rawtypes" })
 	public <T> T callback(Class<? extends EntityCallback> callbackType, T entity, Object... args) {
 
 		Assert.notNull(entity, "Entity must not be null");

src/main/java/org/springframework/data/mapping/callback/DefaultReactiveEntityCallbacks.java

@@ -63,14 +63,12 @@ class DefaultReactiveEntityCallbacks implements ReactiveEntityCallbacks {
 	}
 
 	@Override
-	@SuppressWarnings("unchecked")
+	@SuppressWarnings({ "unchecked", "rawtypes" })
 	public <T> Mono<T> callback(Class<? extends EntityCallback> callbackType, T entity, Object... args) {
 
 		Assert.notNull(entity, "Entity must not be null");
 
-		Class<T> entityType = (Class<T>) (entity != null
+		Class<T> entityType = (Class<T>) ClassUtils.getUserClass(entity.getClass());
-				? ClassUtils.getUserClass(entity.getClass())
-				: callbackDiscoverer.resolveDeclaredEntityType(callbackType).getRawClass());
 
 		Method callbackMethod = callbackMethodCache.computeIfAbsent(callbackType, it -> {
 

src/main/java/org/springframework/data/mapping/callback/EntityCallbacks.java

@@ -47,6 +47,7 @@ public interface EntityCallbacks {
 	 * @return never {@literal null}.
 	 * @throws IllegalArgumentException if a required argument is {@literal null}.
 	 */
+	@SuppressWarnings("rawtypes")
 	<T> T callback(Class<? extends EntityCallback> callbackType, T entity, Object... args);
 
 	/**

src/main/java/org/springframework/data/mapping/callback/ReactiveEntityCallbacks.java

@@ -50,6 +50,7 @@ public interface ReactiveEntityCallbacks {
 	 * @return a {@link Mono} emitting the result after invoking the callbacks.
 	 * @throws IllegalArgumentException if a required argument is {@literal null}.
 	 */
+	@SuppressWarnings("rawtypes")
 	<T> Mono<T> callback(Class<? extends EntityCallback> callbackType, T entity, Object... args);
 
 	/**