Clean up warnings in spring-core

spring-core/src/main/java/org/springframework/core/env/PropertySourcesPropertyResolver.java

@@ -16,9 +16,6 @@
 
 package org.springframework.core.env;
 
-import org.springframework.core.convert.ConversionException;
-import org.springframework.util.ClassUtils;
-
 /**
  * {@link PropertyResolver} implementation that resolves property values against
  * an underlying set of {@link PropertySources}.

spring-core/src/main/java/org/springframework/util/concurrent/ListenableFutureCallbackRegistry.java

@@ -91,7 +91,6 @@ public class ListenableFutureCallbackRegistry<T> {
 	 * @param callback the success callback to add
 	 * @since 4.1
 	 */
-	@SuppressWarnings("unchecked")
 	public void addSuccessCallback(SuccessCallback<? super T> callback) {
 		Assert.notNull(callback, "'callback' must not be null");
 		synchronized (this.mutex) {