Share instances of the custom Gson type serializers

proxy/src/main/java/com/velocitypowered/proxy/VelocityServer.java

@@ -91,20 +91,20 @@ public class VelocityServer implements ProxyServer, ForwardingAudience {
 
   private static final Logger logger = LogManager.getLogger(VelocityServer.class);
   public static final Gson GENERAL_GSON = new GsonBuilder()
-      .registerTypeHierarchyAdapter(Favicon.class, new FaviconSerializer())
-      .registerTypeHierarchyAdapter(GameProfile.class, new GameProfileSerializer())
+      .registerTypeHierarchyAdapter(Favicon.class, FaviconSerializer.INSTANCE)
+      .registerTypeHierarchyAdapter(GameProfile.class, GameProfileSerializer.INSTANCE)
       .create();
   private static final Gson PRE_1_16_PING_SERIALIZER = ProtocolUtils
       .getJsonChatSerializer(ProtocolVersion.MINECRAFT_1_15_2)
       .serializer()
       .newBuilder()
-      .registerTypeHierarchyAdapter(Favicon.class, new FaviconSerializer())
+      .registerTypeHierarchyAdapter(Favicon.class, FaviconSerializer.INSTANCE)
       .create();
   private static final Gson POST_1_16_PING_SERIALIZER = ProtocolUtils
       .getJsonChatSerializer(ProtocolVersion.MINECRAFT_1_16)
       .serializer()
       .newBuilder()
-      .registerTypeHierarchyAdapter(Favicon.class, new FaviconSerializer())
+      .registerTypeHierarchyAdapter(Favicon.class, FaviconSerializer.INSTANCE)
       .create();
 
   private final ConnectionManager cm;

proxy/src/main/java/com/velocitypowered/proxy/protocol/util/FaviconSerializer.java

@@ -11,6 +11,12 @@ import java.lang.reflect.Type;
 
 public final class FaviconSerializer implements JsonSerializer<Favicon>, JsonDeserializer<Favicon> {
 
+  public static final FaviconSerializer INSTANCE = new FaviconSerializer();
+
+  private FaviconSerializer() {
+
+  }
+
   @Override
   public Favicon deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) {
     return new Favicon(json.getAsString());

proxy/src/main/java/com/velocitypowered/proxy/protocol/util/GameProfileSerializer.java

@@ -16,8 +16,13 @@ import java.util.List;
 public final class GameProfileSerializer implements JsonSerializer<GameProfile>,
     JsonDeserializer<GameProfile> {
 
+  public static final GameProfileSerializer INSTANCE = new GameProfileSerializer();
   private static final Type propertyList = new TypeToken<List<Property>>() {}.getType();
 
+  private GameProfileSerializer() {
+
+  }
+
   @Override
   public GameProfile deserialize(JsonElement json, Type typeOfT,
       JsonDeserializationContext context) {