Add runnable list to be executed before the full init

common/src/main/java/us/myles/ViaVersion/ViaManager.java

@@ -15,7 +15,9 @@ import us.myles.ViaVersion.protocols.protocol1_13to1_12_2.TabCompleteThread;
 import us.myles.ViaVersion.protocols.protocol1_9to1_8.ViaIdleThread;
 import us.myles.ViaVersion.update.UpdateUtil;
 
+import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.UUID;
@@ -28,6 +30,7 @@ public class ViaManager {
     private final ViaCommandHandler commandHandler;
     private final ViaPlatformLoader loader;
     private final Set<String> subPlatforms = new HashSet<>();
+    private List<Runnable> enableListeners = new ArrayList<>();
     private TaskId mappingLoadingTask;
     private boolean debug;
 
@@ -48,10 +51,13 @@ public class ViaManager {
             platform.onReload();
         }
         // Check for updates
-        if (platform.getConf().isCheckForUpdates())
+        if (platform.getConf().isCheckForUpdates()) {
             UpdateUtil.sendUpdateMessage();
+        }
+
         // Force class load
         ProtocolRegistry.init();
+
         // Inject
         try {
             injector.inject();
@@ -60,11 +66,17 @@ public class ViaManager {
             e.printStackTrace();
             return;
         }
+
         // Mark as injected
         System.setProperty("ViaVersion", platform.getPluginVersion());
+
+        for (Runnable listener : enableListeners) {
+            listener.run();
+        }
+        enableListeners = null;
+
         // If successful
         platform.runSync(this::onServerLoaded);
-
     }
 
     public void onServerLoaded() {
@@ -195,6 +207,15 @@ public class ViaManager {
         return platform.getConnectionManager().getConnectedClient(playerUUID);
     }
 
+    /**
+     * Adds a runnable to be executed when ViaVersion has finished its init before the full server load.
+     *
+     * @param runnable runnable to be executed
+     */
+    public void addEnableListener(Runnable runnable) {
+        enableListeners.add(runnable);
+    }
+
     public static final class ViaManagerBuilder {
         private ViaPlatform<?> platform;
         private ViaInjector injector;

common/src/main/java/us/myles/ViaVersion/exception/InformativeException.java

@@ -5,7 +5,7 @@ import java.util.Map;
 
 public class InformativeException extends Exception {
     private final Map<String, Object> info = new HashMap<>();
-    private int sources = 0;
+    private int sources;
 
     public InformativeException(Throwable cause) {
         super(cause);

velocity/src/main/java/us/myles/ViaVersion/VelocityPlugin.java

@@ -2,6 +2,7 @@ package us.myles.ViaVersion;
 
 import com.google.gson.JsonObject;
 import com.google.inject.Inject;
+import com.velocitypowered.api.event.PostOrder;
 import com.velocitypowered.api.event.Subscribe;
 import com.velocitypowered.api.event.proxy.ProxyInitializeEvent;
 import com.velocitypowered.api.plugin.Plugin;
@@ -82,7 +83,10 @@ public class VelocityPlugin implements ViaPlatform<Player> {
         if (proxy.getPluginManager().getPlugin("ViaBackwards").isPresent()) {
             MappingDataLoader.enableMappingsCache();
         }
+    }
 
+    @Subscribe(order = PostOrder.LAST)
+    public void onProxyLateInit(ProxyInitializeEvent e) {
         Via.getManager().init();
     }