#vulnerable code 
                                @Test
    public void shouldDetermineQueueDirectoryFromQueueFile() throws Exception {
        final File queuePath = DirectoryUtils.tempDir(getClass().getSimpleName());
        try (final SingleChronicleQueue queue =
                     SingleChronicleQueueBuilder.binary(queuePath)
                             .testBlockSize()
                             .build()) {
            try (DocumentContext ctx = queue.acquireAppender().writingDocument()) {
                ctx.wire().write("key").text("value");
            }
        }
        final Path path = queuePath.listFiles(QUEUE_FILE_FILTER)[0].toPath();
        try (final SingleChronicleQueue queue =
                     SingleChronicleQueueBuilder.binary(path)
                             .testBlockSize()
                             .build()) {
            assertThat(queue.createTailer().readingDocument().isPresent(), is(true));
        }
    } 
                            #location 9 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Test
    public void shouldDetermineQueueDirectoryFromQueueFile() throws Exception {
        final Path path = Paths.get(OS.USER_DIR, TEST_QUEUE_FILE);
        try (final SingleChronicleQueue queue =
                     SingleChronicleQueueBuilder.binary(path)
                             .testBlockSize()
                             .build()) {
            assertThat(queue.createTailer().readingDocument().isPresent(), is(true));
        }
    }