#fixed code
                                private static void assertSigned(File outFolder, List<File> uApks) throws Exception {
        assertNotNull(outFolder);
        File[] outFiles = outFolder.listFiles(pathname -> FileUtil.getFileExtension(pathname).toLowerCase().equals("apk"));
        System.out.println("Found " + outFiles.length + " apks in out dir");
        assertNotNull(outFiles);
        assertEquals("should be same count of apks in out folder", uApks.size(), outFiles.length);

        for (File outFile : outFiles) {
            AndroidApkSignerVerify.Result verifyResult = new AndroidApkSignerVerify().verify(outFile, null, null, false);
            assertTrue(verifyResult.verified);
            assertEquals(0, verifyResult.warning);
        }
    }
#vulnerable code 
                                private static void assertSigned(File outFolder, List<File> uApks) throws Exception {
        assertNotNull(outFolder);
        File[] outFiles = outFolder.listFiles();
        assertNotNull(outFiles);
        assertEquals("should be same count of apks in out folder", uApks.size(), outFiles.length);

        for (File outFile : outFiles) {
            AndroidApkSignerVerify.Result verifyResult = new AndroidApkSignerVerify().verify(outFile, null, null, false);
            assertTrue(verifyResult.verified);
            assertEquals(0, verifyResult.warning);
        }
    } 
                            #location 5 
                            #vulnerability type NULL_DEREFERENCE