Remove KeyedObject interface (#7680)

patches/server/0568-Empty-commands-shall-not-be-dispatched.patch

@@ -0,0 +1,18 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Mariell Hoversholm <proximyst@proximyst.com>
+Date: Wed, 6 Jan 2021 23:38:43 +0100
+Subject: [PATCH] Empty commands shall not be dispatched
+
+
+diff --git a/src/main/java/net/minecraft/commands/Commands.java b/src/main/java/net/minecraft/commands/Commands.java
+index 4bc28b66788d06d1446284f5adef6a44be736f92..e195ef979984ea7ffe4558c42ebabadf2a00950a 100644
+--- a/src/main/java/net/minecraft/commands/Commands.java
++++ b/src/main/java/net/minecraft/commands/Commands.java
+@@ -241,6 +241,7 @@ public class Commands {
+         command = event.getCommand();
+ 
+         String[] args = command.split(" ");
++        if (args.length == 0) return 0; // Paper - empty commands shall not be dispatched
+ 
+         String cmd = args[0];
+         if (cmd.startsWith("minecraft:")) cmd = cmd.substring("minecraft:".length());