垃圾收集器停止收集适量的对象

Question

我有一个程序，它读取一个包含指定速率的400万行的巨大文件，并将这些行发送到Kafka集群。这是该程序的代码：

try (BufferedReader br = new BufferedReader(new FileReader(path.toString()))) {
    String line = null;
    do {
        long start = System.currentTimeMillis();
        // rate is is the number of messages per second
        for (int i = 0; i < rate; i++) {
            line = br.readLine();
            if (line != null) {
                // asynchronously send to the Kafka cluster
                producer.send(new ProducerRecord<>(Config.KAFKA_TOPIC, Integer.toString(getNextInt()), line));
            } else break;
        }
        long finish = System.currentTimeMillis() - start;
        long sleepTime = 1000 - finish;
        if (sleepTime > 0)
            Thread.sleep(sleepTime);
        else
            System.out.println(sleepTime + " is negative");
    } while (line != null);
    br.close();
}
catch (InterruptedException | IOException | IllegalArgumentException ex) {
    ex.printStackTrace();
}

在这种情况发生之前一切正常：

GC停止收集适量的对象，程序无法再保持读取率。我试图在System.gc()之前调用Thread.sleep()，但它始终不起作用。可能是什么问题？