Added getting resources from the JAR

src/main/java/emu/grasscutter/plugin/Plugin.java

 package emu.grasscutter.plugin;
 
 import emu.grasscutter.Grasscutter;
+import emu.grasscutter.plugin.api.ServerHook;
 import emu.grasscutter.server.game.GameServer;
 
+import java.io.InputStream;
+import java.net.URLClassLoader;
+
 /**
  * The base class for all plugins to extend.
  */
 public abstract class Plugin {
+    private final ServerHook server = ServerHook.getInstance();
+    
     private PluginIdentifier identifier;
+    private URLClassLoader classLoader;
 
     /**
      * This method is reflected into.
@@ -15,9 +22,11 @@ public abstract class Plugin {
      * Set plugin variables.
      * @param identifier The plugin's identifier.
      */
-    private void initializePlugin(PluginIdentifier identifier) {
+    private void initializePlugin(PluginIdentifier identifier, URLClassLoader classLoader) {
         if(this.identifier == null)
             this.identifier = identifier;
+        if(this.classLoader == null)
+            this.classLoader = classLoader;
         else Grasscutter.getLogger().warn(this.identifier.name + " had a reinitialization attempt.");
     }
 
@@ -55,7 +64,24 @@ public abstract class Plugin {
      * @return A server instance.
      */
     public final GameServer getServer() {
-        return Grasscutter.getGameServer();
+        return this.server.getGameServer();
+    }
+
+    /**
+     * Returns an input stream for a resource in the JAR file.
+     * @param resourceName The name of the resource.
+     * @return An input stream.
+     */
+    public final InputStream getResource(String resourceName) {
+        return this.classLoader.getResourceAsStream(resourceName);
+    }
+
+    /**
+     * Returns the server hook.
+     * @return A server hook singleton.
+     */
+    public final ServerHook getHandle() {
+        return this.server;
     }
     
     /* Called when the plugin is first loaded. */

src/main/java/emu/grasscutter/plugin/PluginManager.java

@@ -73,7 +73,7 @@ public final class PluginManager {
                     
                     Class<?> pluginClass = loader.loadClass(pluginConfig.mainClass);
                     Plugin pluginInstance = (Plugin) pluginClass.getDeclaredConstructor().newInstance();
-                    this.loadPlugin(pluginInstance, PluginIdentifier.fromPluginConfig(pluginConfig));
+                    this.loadPlugin(pluginInstance, PluginIdentifier.fromPluginConfig(pluginConfig), loader);
                     
                     fileReader.close(); // Close the file reader.
                 } catch (ClassNotFoundException ignored) {
@@ -89,14 +89,14 @@ public final class PluginManager {
      * Load the specified plugin.
      * @param plugin The plugin instance.
      */
-    private void loadPlugin(Plugin plugin, PluginIdentifier identifier) {
+    private void loadPlugin(Plugin plugin, PluginIdentifier identifier, URLClassLoader classLoader) {
         Grasscutter.getLogger().info("Loading plugin: " + identifier.name);
         
         // Add the plugin's identifier.
         try {
             Class<Plugin> pluginClass = Plugin.class;
-            Method method = pluginClass.getDeclaredMethod("initializePlugin", PluginIdentifier.class);
-            method.setAccessible(true); method.invoke(plugin, identifier); method.setAccessible(false);
+            Method method = pluginClass.getDeclaredMethod("initializePlugin", PluginIdentifier.class, URLClassLoader.class);
+            method.setAccessible(true); method.invoke(plugin, identifier, classLoader); method.setAccessible(false);
         } catch (Exception ignored) {
             Grasscutter.getLogger().warn("Failed to add plugin identifier: " + identifier.name);
         }