-import com.google.common.base.Optional;
-import com.google.common.base.Preconditions;
-import com.google.common.collect.HashMultimap;
-import com.google.common.collect.Lists;
-import com.google.common.collect.Maps;
-import com.google.common.collect.Multimap;
+import static com.google.common.base.Preconditions.checkState;
+import static java.lang.String.format;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import javax.management.ObjectName;
+