#vulnerable code 
                                @Test
    public void classpathResourceHandlerTest() throws URISyntaxException {
        ClasspathResourceHandler handler = new ClasspathResourceHandler("/", "/public");

        URL resourceUrl = handler.getResourceUrl("VISIBLE");
        assertNotNull(resourceUrl);
        Path visibleFile = Paths.get(resourceUrl.toURI());
        assertNotNull(visibleFile);
        Path basePath = visibleFile.getParent();
        URL url = handler.getResourceUrl("../HIDDEN");
        assertNotNull(url);
        assertTrue("Path traversal security issue", Paths.get(url.toURI()).startsWith(basePath));
    } 
                            #location 12 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Test
    public void classpathResourceHandlerTest() throws URISyntaxException {
        ClasspathResourceHandler handler = new ClasspathResourceHandler("/", "/public");

        URL resourceUrl = handler.getResourceUrl("VISIBLE");
        assertNotNull(resourceUrl);
        Path visibleFile = Paths.get(resourceUrl.toURI());
        assertNotNull(visibleFile);

        URL url = handler.getResourceUrl("../HIDDEN");
        assertNull(url);
    }