public static ShenyuPluginLoader getInstance() {
        if (null == pluginLoader) {
            synchronized (ShenyuPluginLoader.class) {
                if (null == pluginLoader) {
                    pluginLoader = new ShenyuPluginLoader();
                }
            }
        }
        return pluginLoader;
    }
@Test
    public void testGetInstance() {
        assertThat(shenyuPluginLoader, is(ShenyuPluginLoader.getInstance()));
    }