Implement nasty workaround for Spigot's changes to the PluginClassLoader (#648)

common/src/main/java/me/lucko/luckperms/common/dependencies/DependencyManager.java

@@ -186,18 +186,12 @@ public class DependencyManager {
         }
     }
 
-    private  void loadJar(File file) {
+    private void loadJar(File file) {
         // get the classloader to load into
-        ClassLoader classLoader = plugin.getClass().getClassLoader();
-
-        if (classLoader instanceof URLClassLoader) {
-            try {
-                ADD_URL_METHOD.invoke(classLoader, file.toURI().toURL());
-            } catch (IllegalAccessException | InvocationTargetException | MalformedURLException e) {
-                throw new RuntimeException("Unable to invoke URLClassLoader#addURL", e);
-            }
-        } else {
-            throw new RuntimeException("Unknown classloader type: " + classLoader.getClass());
+        try {
+            plugin.loadUrlIntoClasspath(file.toURI().toURL());
+        } catch (MalformedURLException e) {
+            throw new RuntimeException(e);
         }
     }
 
@@ -210,4 +204,16 @@ public class DependencyManager {
         }
     }
 
+    public static void loadUrlIntoClassLoader(URL url, ClassLoader classLoader) {
+        if (classLoader instanceof URLClassLoader) {
+            try {
+                ADD_URL_METHOD.invoke(classLoader, url);
+            } catch (IllegalAccessException | InvocationTargetException e) {
+                throw new RuntimeException("Unable to invoke URLClassLoader#addURL", e);
+            }
+        } else {
+            throw new RuntimeException("Unknown classloader type: " + classLoader.getClass());
+        }
+    }
+
 }

common/src/main/java/me/lucko/luckperms/common/plugin/LuckPermsPlugin.java

@@ -55,6 +55,7 @@ import me.lucko.luckperms.common.verbose.VerboseHandler;
 
 import java.io.File;
 import java.io.InputStream;
+import java.net.URL;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -154,6 +155,15 @@ public interface LuckPermsPlugin {
      */
     DependencyManager getDependencyManager();
 
+    /**
+     * Loads a dependency into the plugins classpath
+     *
+     * @param url the url to load
+     */
+    default void loadUrlIntoClasspath(URL url) {
+        DependencyManager.loadUrlIntoClassLoader(url, getClass().getClassLoader());
+    }
+
     /**
      * Gets the context manager.
      * This object handles context accumulation for all players on the platform.