Pass closable around instead of closing it straight away.

- Ensures ServerUtils can reload itself :)

src/main/java/net/frankheijden/serverutils/ServerUtils.java

@@ -130,7 +130,11 @@ public class ServerUtils extends JavaPlugin implements CommandExecutor {
         return commandManager;
     }
 
-    private File[] getJars() {
+    /**
+     * Retrieves all files with a jar extension in the plugins/ folder.
+     * @return An array of jar files.
+     */
+    public File[] getJars() {
         File parent = getDataFolder().getParentFile();
         if (parent == null) return new File[0];
         return parent.listFiles(f -> f.getName().endsWith(".jar"));

src/main/java/net/frankheijden/serverutils/commands/CommandServerUtils.java

@@ -19,6 +19,7 @@ import java.util.Set;
 
 import net.frankheijden.serverutils.ServerUtils;
 import net.frankheijden.serverutils.config.Messenger;
+import net.frankheijden.serverutils.managers.CloseableResult;
 import net.frankheijden.serverutils.managers.LoadResult;
 import net.frankheijden.serverutils.managers.PluginManager;
 import net.frankheijden.serverutils.managers.Result;
@@ -171,8 +172,9 @@ public class CommandServerUtils extends BaseCommand {
             return;
         }
 
-        Result unloadResult = PluginManager.unloadPlugin(pluginName);
+        CloseableResult result = PluginManager.unloadPlugin(pluginName);
-        unloadResult.sendTo(sender, "unload", pluginName);
+        result.getResult().sendTo(sender, "unload", pluginName);
+        result.tryClose();
     }
 
     /**
@@ -185,8 +187,9 @@ public class CommandServerUtils extends BaseCommand {
     @CommandPermission("serverutils.reloadplugin")
     @Description("Reloads a specified plugin.")
     public void onReloadPlugin(CommandSender sender, String pluginName) {
-        Result result = PluginManager.reloadPlugin(pluginName);
+        CloseableResult result = PluginManager.reloadPlugin(pluginName);
-        result.sendTo(sender, "reload", pluginName);
+        result.getResult().sendTo(sender, "reload", pluginName);
+        result.tryClose();
     }
 
     /**

src/main/java/net/frankheijden/serverutils/managers/CloseableResult.java

@@ -0,0 +1,55 @@
+package net.frankheijden.serverutils.managers;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+public class CloseableResult implements Closeable {
+
+    private Result result;
+    private final Closeable closeable;
+
+    /**
+     * Constructs a new closable result.
+     * Used for unloading / reloading a plugin.
+     * NB: The closable needs to be closed to fully ensure that the old plugin doesn't work anymore!
+     * @param result The result of the procedure
+     * @param closeable The closable of the procedure.
+     */
+    public CloseableResult(Result result, Closeable closeable) {
+        this.result = result;
+        this.closeable = closeable;
+    }
+
+    public CloseableResult(Result result) {
+        this(result, null);
+    }
+
+    public CloseableResult(Closeable closeable) {
+        this(Result.SUCCESS, closeable);
+    }
+
+    public Result getResult() {
+        return result;
+    }
+
+    public CloseableResult set(Result result) {
+        this.result = result;
+        return this;
+    }
+
+    /**
+     * Attempts to close the closable, essentially wrapping it with try-catch.
+     */
+    public void tryClose() {
+        try {
+            close();
+        } catch (IOException ex) {
+            ex.printStackTrace();
+        }
+    }
+
+    @Override
+    public void close() throws IOException {
+        closeable.close();
+    }
+}

src/main/java/net/frankheijden/serverutils/managers/PluginManager.java

@@ -1,5 +1,6 @@
 package net.frankheijden.serverutils.managers;
 
+import java.io.Closeable;
 import java.io.File;
 import java.lang.reflect.InvocationTargetException;
 import java.util.Map;
@@ -102,7 +103,7 @@ public class PluginManager {
      * @param pluginName The plugin to unload.
      * @return The result of the unload.
      */
-    public static Result unloadPlugin(String pluginName) {
+    public static CloseableResult unloadPlugin(String pluginName) {
         return unloadPlugin(Bukkit.getPluginManager().getPlugin(pluginName));
     }
 
@@ -111,17 +112,18 @@ public class PluginManager {
      * @param plugin The plugin to unload.
      * @return The result of the unload.
      */
-    public static Result unloadPlugin(Plugin plugin) {
+    public static CloseableResult unloadPlugin(Plugin plugin) {
-        if (plugin == null) return Result.NOT_EXISTS;
+        if (plugin == null) return new CloseableResult(Result.NOT_EXISTS);
+        Closeable closeable;
         try {
             RSimplePluginManager.getPlugins(Bukkit.getPluginManager()).remove(plugin);
             RSimplePluginManager.removeLookupName(Bukkit.getPluginManager(), plugin.getName());
-            RPluginClassLoader.clearClassLoader(RJavaPlugin.getClassLoader(plugin));
+            closeable = RPluginClassLoader.clearClassLoader(RJavaPlugin.getClassLoader(plugin));
         } catch (Exception ex) {
             ex.printStackTrace();
-            return Result.ERROR;
+            return new CloseableResult(Result.ERROR);
         }
-        return Result.SUCCESS;
+        return new CloseableResult(closeable);
     }
 
     /**
@@ -153,9 +155,9 @@ public class PluginManager {
      * @param pluginName The plugin to reload.
      * @return The result of the reload.
      */
-    public static Result reloadPlugin(String pluginName) {
+    public static CloseableResult reloadPlugin(String pluginName) {
         Plugin plugin = Bukkit.getPluginManager().getPlugin(pluginName);
-        if (plugin == null) return Result.NOT_EXISTS;
+        if (plugin == null) return new CloseableResult(Result.NOT_EXISTS);
         return reloadPlugin(plugin);
     }
 
@@ -164,27 +166,29 @@ public class PluginManager {
      * @param plugin The plugin to reload.
      * @return The result of the reload.
      */
-    public static Result reloadPlugin(Plugin plugin) {
+    public static CloseableResult reloadPlugin(Plugin plugin) {
         Result disableResult = disablePlugin(plugin);
-        if (disableResult != Result.SUCCESS && disableResult != Result.ALREADY_DISABLED) return disableResult;
+        if (disableResult != Result.SUCCESS && disableResult != Result.ALREADY_DISABLED) {
+            return new CloseableResult(disableResult);
+        }
 
-        Result unloadResult = unloadPlugin(plugin);
+        CloseableResult result = unloadPlugin(plugin);
-        if (unloadResult != Result.SUCCESS) return unloadResult;
+        if (result.getResult() != Result.SUCCESS) return result;
 
         File pluginFile;
         try {
             pluginFile = RPlugin.getPluginFile(plugin);
         } catch (InvocationTargetException | IllegalAccessException ex) {
             ex.printStackTrace();
-            return Result.ERROR;
+            return result.set(Result.ERROR);
         }
 
         LoadResult loadResult = loadPlugin(pluginFile);
         if (!loadResult.isSuccess()) {
             Result r = loadResult.getResult();
-            return (r == Result.NOT_EXISTS) ? Result.FILE_CHANGED : r;
+            return result.set((r == Result.NOT_EXISTS) ? Result.FILE_CHANGED : r);
         }
-        return enablePlugin(loadResult.getPlugin());
+        return result.set(enablePlugin(loadResult.getPlugin()));
     }
 
     /**

src/main/java/net/frankheijden/serverutils/reflection/RPluginClassLoader.java

@@ -5,9 +5,8 @@ import static net.frankheijden.serverutils.reflection.ReflectionUtils.VersionPar
 import static net.frankheijden.serverutils.reflection.ReflectionUtils.getAllFields;
 import static net.frankheijden.serverutils.reflection.ReflectionUtils.set;
 
-import java.io.IOException;
+import java.io.Closeable;
 import java.lang.reflect.Field;
-import java.net.URLClassLoader;
 import java.util.Map;
 
 public class RPluginClassLoader {
@@ -32,20 +31,18 @@ public class RPluginClassLoader {
 
     /**
      * Clears and closes the provided classloader.
-     * Remov
      * @param loader The classloader instance.
-     * @throws IOException When closing the loader failed.
+     * @return The Closeable object.
      * @throws IllegalAccessException When prohibited access to the field.
      */
-    public static void clearClassLoader(ClassLoader loader) throws IOException, IllegalAccessException {
+    public static Closeable clearClassLoader(ClassLoader loader) throws IllegalAccessException {
-        if (loader == null) return;
+        if (loader == null) return null;
         if (isInstance(loader)) {
             clearUrlClassLoader(loader);
         }
 
-        if (loader instanceof URLClassLoader) {
+        if (loader instanceof Closeable) return (Closeable) loader;
-            ((URLClassLoader) loader).close();
+        return null;
-        }
     }
 
     /**