Spring Cleaning in December

- Delete unused imports
- Delete unused code
- Clean up warnings

spring-beans/src/main/java/org/springframework/beans/factory/support/MethodOverrides.java

@@ -17,7 +17,6 @@
 package org.springframework.beans.factory.support;
 
 import java.lang.reflect.Method;
-import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.Set;