#vulnerable code 
                                @Override
    public void close() throws IOException {
        if (this.queueFrontIndexPageFactory != null) {
            this.queueFrontIndexPageFactory.releaseCachedPages();
        }

        if (dequeueFuture != null) {
            /* Cancel the future but don't interrupt running tasks
            because they might perform further work not refering to the queue
             */
            dequeueFuture.cancel(false);
        }

        this.innerArray.close();
    } 
                            #location 11 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                @Override
    public void close() throws IOException {
        if (this.queueFrontIndexPageFactory != null) {
            this.queueFrontIndexPageFactory.releaseCachedPages();
        }


        synchronized (futureLock) {

            /* Cancel the future but don't interrupt running tasks
            because they might perform further work not refering to the queue
             */
            if (peekFuture != null) {

                peekFuture.cancel(false);
            }
            if (dequeueFuture != null) {
                dequeueFuture.cancel(false);
            }
        }

        this.innerArray.close();
    }