Fix exception when application is launched with arguments

Author: emmanue1

app/src/main/java/org/jd/gui/App.java

@@ -59,8 +59,7 @@ public static void main(String[] args) {
 
             // Create main controller and show main frame
             controller = new MainController(configuration);
-            controller.show();
-            controller.openFiles(newList(args));
+            controller.show(newList(args));
 		}
 	}
 

app/src/main/java/org/jd/gui/controller/MainController.java

@@ -111,13 +111,13 @@ public MainController(Configuration configuration) {
 
 	// --- Show GUI --- //
     @SuppressWarnings("unchecked")
-	public void show() {
+	public void show(List<File> files) {
         SwingUtil.invokeLater(() -> {
             // Show main frame
-            mainView.show(
-                    configuration.getMainWindowLocation(),
-                    configuration.getMainWindowSize(),
-                    configuration.isMainWindowMaximize());
+            mainView.show(configuration.getMainWindowLocation(), configuration.getMainWindowSize(), configuration.isMainWindowMaximize());
+            if (!files.isEmpty()) {
+                openFiles(files);
+            }
         });
 
         // Background initializations