+import static com.google.common.base.Preconditions.checkNotNull;
+import static java.lang.String.format;
+import com.google.common.collect.Lists;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
+import javax.management.DynamicMBean;
+import javax.management.InstanceAlreadyExistsException;
+import javax.management.InstanceNotFoundException;
+import javax.management.MBeanServer;
+import javax.management.ObjectName;