Fix NPE when temp ip bans expire (#3373)

Spigot-Server-Patches/0271-Use-ConcurrentHashMap-in-JsonList.patch

@@ -98,3 +98,16 @@ index 734e7ecf630aa13a30d72ff96e57e5d0faf35013..8570e38f42e2f489e2899ac2f0c4a7b8
          Collection<V> collection = this.d.values();
          String s = this.b.toJson(collection);
          BufferedWriter bufferedwriter = null;
+diff --git a/src/main/java/net/minecraft/server/PlayerList.java b/src/main/java/net/minecraft/server/PlayerList.java
+index b69cff40922ba2d1a44c11bcae86f9439130ad96..22f18be4627fefe500239f7a35eee3b019bcffcc 100644
+--- a/src/main/java/net/minecraft/server/PlayerList.java
++++ b/src/main/java/net/minecraft/server/PlayerList.java
+@@ -512,7 +512,7 @@ public abstract class PlayerList {
+         } else if (!this.isWhitelisted(gameprofile, event)) { // Paper
+             chatmessage = new ChatMessage("multiplayer.disconnect.not_whitelisted", new Object[0]);
+             //event.disallow(PlayerLoginEvent.Result.KICK_WHITELIST, org.spigotmc.SpigotConfig.whitelistMessage); // Spigot // Paper - moved to isWhitelisted
+-        } else if (getIPBans().isBanned(socketaddress) && !getIPBans().get(socketaddress).hasExpired()) {
++        } else if (getIPBans().isBanned(socketaddress) && getIPBans().get(socketaddress) != null && !getIPBans().get(socketaddress).hasExpired()) { // Paper - fix NPE with temp ip bans
+             IpBanEntry ipbanentry = this.l.get(socketaddress);
+ 
+             chatmessage = new ChatMessage("multiplayer.disconnect.banned_ip.reason", new Object[]{ipbanentry.getReason()});