@Test
public void testReturnsSameInstance() {

    String path = "/a/b/c/d/e";
    String expr = "/a/b/{c}/d/e";
    PathFilter regexpPathUriFilter = new DefaultPathFilter("XXX", expr);
    String result1 = regexpPathUriFilter.filter(path);
    String result2 = regexpPathUriFilter.filter(path);
    assertThat(result1, sameInstance(result2));
}