Spring Cleaning in December

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

spring-context/src/main/java/org/springframework/format/datetime/standard/PeriodFormatter.java

@@ -17,7 +17,6 @@
 package org.springframework.format.datetime.standard;
 
 import java.text.ParseException;
-import java.time.Instant;
 import java.time.Period;
 import java.util.Locale;
 

spring-context/src/test/java/org/springframework/cache/config/ExpressionCachingIntegrationTests.java

@@ -92,6 +92,7 @@ public class ExpressionCachingIntegrationTests {
 			this.id = id;
 		}
 
+		@SuppressWarnings("unused")
 		public String getId() {
 			return id;
 		}
@@ -104,6 +105,7 @@ public class ExpressionCachingIntegrationTests {
 			this.id = id;
 		}
 
+		@SuppressWarnings("unused")
 		public String getId() {
 			return id;
 		}

spring-context/src/test/java/org/springframework/context/event/AbstractApplicationEventListenerTests.java

@@ -117,13 +117,13 @@ public abstract class AbstractApplicationEventListenerTests {
 		}
 	}
 
+	@SuppressWarnings("rawtypes")
 	static class RawApplicationListener implements ApplicationListener {
 		@Override
 		public void onApplicationEvent(ApplicationEvent event) {
 		}
 	}
 
-	@SuppressWarnings("unused")
 	static class TestEvents {
 
 		public ApplicationEvent applicationEvent;