class Test { { UrlClassLoader loader = UrlClassLoader.build(). useCache(new UrlClassLoader.I() { @Override public void m() {} }).get(); System.out.println(loader); } static class UrlClassLoader { static UrlClassLoader build() {return new UrlClassLoader();} UrlClassLoader useCache(I i) { return this; } interface I { void m(); } UrlClassLoader get() { return this; } } }