#vulnerable code 
                                @Override
    public void init() {
        final long timeoutAt = System.currentTimeMillis() + TimeUnit.SECONDS.toMillis(20L);
        boolean warnedOnFailure = false;
        while (System.currentTimeMillis() < timeoutAt) {
            try (final FileChannel channel = FileChannel.open(tableStore.file().toPath(),
                    StandardOpenOption.WRITE);
                 final FileLock fileLock = channel.tryLock()) {
                maxCycleValue = tableStore.acquireValueFor(HIGHEST_CREATED_CYCLE);
                minCycleValue = tableStore.acquireValueFor(LOWEST_CREATED_CYCLE);
                lock = tableStore.acquireValueFor(LOCK);
                modCount = tableStore.acquireValueFor(MOD_COUNT);
                if (lock.getVolatileValue() == Long.MIN_VALUE) {
                    lock.compareAndSwapValue(Long.MIN_VALUE, 0);
                }
                if (modCount.getVolatileValue() == Long.MIN_VALUE) {
                    modCount.compareAndSwapValue(Long.MIN_VALUE, 0);
                }
                return;
            } catch (IOException | RuntimeException e) {
                // failed to acquire the lock, wait until other operation completes
                if (!warnedOnFailure) {
                    LOGGER.warn("Failed to acquire a lock on the directory-listing file: {}:{}. Retrying.",
                            e.getClass().getSimpleName(), e.getMessage());
                    warnedOnFailure = true;
                }
                Jvm.pause(50L);
            }
        }

        throw new IllegalStateException("Unable to claim exclusive lock on file " + tableStore.file());
    } 
                            #location 6 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public void init() {
        tableStore.doWithExclusiveLock(ts -> {
            maxCycleValue = ts.acquireValueFor(HIGHEST_CREATED_CYCLE);
            minCycleValue = ts.acquireValueFor(LOWEST_CREATED_CYCLE);
            lock = ts.acquireValueFor(LOCK);
            modCount = ts.acquireValueFor(MOD_COUNT);
            if (lock.getVolatileValue() == Long.MIN_VALUE) {
                lock.compareAndSwapValue(Long.MIN_VALUE, 0);
            }
            if (modCount.getVolatileValue() == Long.MIN_VALUE) {
                modCount.compareAndSwapValue(Long.MIN_VALUE, 0);
            }
            return this;
        });
    }