下面代码第九行是什么意思？

Question

1. public class ConfigManager {                      //读取配置文件的工具类，单例模式 

3. private static ConfigManager configManager;

4. private static Properties properties;

6. private ConfigManager() {            //必须以private修饰

7. String configFile = "database.properties";

8. properties = new Properties(); 

9. InputStream is = ConfigManager.class.getClassLoader().getResourceAsStream(configFile);

10. try {

12. properties.load(is);

13. is.close();

14. } catch (IOException e) {

15. e.printStackTrace();

16. }

17. }