Revert Spigot PluginClassLoader workaround

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

@@ -103,10 +103,14 @@ public class DependencyManager {
             dependencies.add(Dependency.JEDIS);
         }
 
-        // don't load slf4j or configurate dependencies on sponge, as they're already present
-        if (plugin.getServerType() == PlatformType.SPONGE) {
+        // don't load slf4j if it's already present
+        if (classExists("org.slf4j.Logger") && classExists("org.slf4j.LoggerFactory")) {
             dependencies.remove(Dependency.SLF4J_API);
             dependencies.remove(Dependency.SLF4J_SIMPLE);
+        }
+
+        // don't load configurate dependencies on sponge
+        if (plugin.getServerType() == PlatformType.SPONGE) {
             dependencies.remove(Dependency.CONFIGURATE_CORE);
             dependencies.remove(Dependency.CONFIGURATE_GSON);
             dependencies.remove(Dependency.CONFIGURATE_YAML);
@@ -182,20 +186,14 @@ public class DependencyManager {
         }
     }
 
-    private void loadJar(File file) {
+    private  void loadJar(File file) {
         // get the classloader to load into
-        try {
-            plugin.loadUrlIntoClasspath(file.toURI().toURL());
-        } catch (MalformedURLException e) {
-            throw new RuntimeException(e);
-        }
-    }
+        ClassLoader classLoader = plugin.getClass().getClassLoader();
 
-    public static void loadUrlIntoClassLoader(URL url, ClassLoader classLoader) {
         if (classLoader instanceof URLClassLoader) {
             try {
-                ADD_URL_METHOD.invoke(classLoader, url);
-            } catch (IllegalAccessException | InvocationTargetException e) {
+                ADD_URL_METHOD.invoke(classLoader, file.toURI().toURL());
+            } catch (IllegalAccessException | InvocationTargetException | MalformedURLException e) {
                 throw new RuntimeException("Unable to invoke URLClassLoader#addURL", e);
             }
         } else {
@@ -203,4 +201,13 @@ public class DependencyManager {
         }
     }
 
+    private static boolean classExists(String className) {
+        try {
+            Class.forName(className);
+            return true;
+        } catch (ClassNotFoundException e) {
+            return false;
+        }
+    }
+
 }

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

@@ -55,7 +55,6 @@ 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;
@@ -155,15 +154,6 @@ 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.