Trailing comma observed in the label section of Prometheus metric with Java

Question

I have setup the code to send a counter metric to Prometheus from my java code. Here is my counter and the associated labels:

static final Counter counter = Counter.build().name("sample_counter")
                                    .help("Records the Sample Count").labelNames("method","status").register();

counter.labels("POST","520").inc();

I am getting the following output where I see a trailing comma at the end of the label of the metric, after 520: sample_counter{method="POST",status="520",} 1.0

How do I get rid of this trailing comma at the end of the label?