理解osworkflow.xml：

加載osworkflow.xml過程:
1)DefaultConfiguration中,在load方法中調用getInputStream()以獲取系統的osworkflow.xml文件

在getInputStream方法中：

    PRotected InputStream getInputStream(URL url) {

        InputStream is = null;

        if (url != null) {

            try {

                is = url.openStream();

            } catch (Exception ex) {

            }

        }

        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();

        if (is == null) {

            try {

                is = classLoader.getResourceAsStream("osworkflow.xml");

            } catch (Exception e) {

            }

        }

        if (is == null) {

            try {

                is = classLoader.getResourceAsStream("/osworkflow.xml");

            } catch (Exception e) {

            }

        }