private void startApp(final List<Class<?>> appClass) {
        if (appClass == null || appClass.isEmpty()) {
            JOptionPane.showMessageDialog(
                rootPane,
                "Please select a test from the list",
                "Error",
                JOptionPane.ERROR_MESSAGE
            );
            return;
        }

        executorService.submit(getAppRunner(appClass));
    }
@return FileFilter for searching class files (no inner classes, only
        those with "Test" in the name)
jme3-examples/src/main/java/jme3test/TestChooser.java