core,netty: block server shutdown until the socket is unbound

api/src/main/java/io/grpc/Server.java

@@ -29,8 +29,10 @@ import javax.annotation.concurrent.ThreadSafe;
  */
 @ThreadSafe
 public abstract class Server {
+
   /**
-   * Bind and start the server.
+   * Bind and start the server.  After this call returns, clients may begin connecting to the
+   * listening socket(s).
    *
    * @return {@code this} object
    * @throws IllegalStateException if already started
@@ -102,6 +104,8 @@ public abstract class Server {
 
   /**
    * Initiates an orderly shutdown in which preexisting calls continue but new calls are rejected.
+   * After this call returns, this server has released the listening socket(s) and may be reused by
+   * another server.
    *
    * @return {@code this} object
    * @since 1.0.0
@@ -111,7 +115,8 @@ public abstract class Server {
   /**
    * Initiates a forceful shutdown in which preexisting and new calls are rejected. Although
    * forceful, the shutdown process is still not instantaneous; {@link #isTerminated()} will likely
-   * return {@code false} immediately after this method returns.
+   * return {@code false} immediately after this method returns. After this call returns, this
+   * server has released the listening socket(s) and may be reused by another server.
    *
    * @return {@code this} object
    * @since 1.0.0

core/src/main/java/io/grpc/internal/InternalServer.java

@@ -42,7 +42,9 @@ public interface InternalServer {
   /**
    * Initiates an orderly shutdown of the server. Existing transports continue, but new transports
    * will not be created (once {@link ServerListener#serverShutdown()} callback is called). This
-   * method may only be called once.
+   * method may only be called once.  Blocks until the listening socket(s) have been closed.  If
+   * interrupted, this method will not wait for the close to complete, but it will happen
+   * asynchronously.
    */
   void shutdown();
 

netty/src/main/java/io/grpc/netty/NettyServer.java

@@ -283,6 +283,12 @@ class NettyServer implements InternalServer, InternalWithLogId {
         eventLoopReferenceCounter.release();
       }
     });
+    try {
+      channel.closeFuture().sync();
+    } catch (InterruptedException e) {
+      log.log(Level.FINE, "Interrupted while shutting down", e);
+      Thread.currentThread().interrupt();
+    }
   }
 
   @Override