public void testSingleSimpleStats() {
    StatsCounter counter = new SimpleStatsCounter();
    for (int i = 0; i < 11; i++) {
      counter.recordHits(1);
    }
    for (int i = 0; i < 13; i++) {
      counter.recordLoadSuccess(i);
    }
    for (int i = 0; i < 17; i++) {
      counter.recordLoadException(i);
    }
    for (int i = 0; i < 23; i++) {
      counter.recordMisses(1);
    }

        // For GCM, last 4 bytes should contain incrementing counter
        ByteBuffer buffer1 = ByteBuffer.wrap(nonce1, 12, 4).order(java.nio.ByteOrder.LITTLE_ENDIAN);
        ByteBuffer buffer2 = ByteBuffer.wrap(nonce2, 12, 4).order(java.nio.ByteOrder.LITTLE_ENDIAN);
        int counter1 = buffer1.getInt();
        int counter2 = buffer2.getInt();

        assertEquals(counter1 + 1, counter2, "Counter should increment between nonces");
    }

        AtomicInteger counter1 = new AtomicInteger(0);
        AtomicInteger counter2 = new AtomicInteger(0);

        executor1.addShutdownListener(() -> counter1.incrementAndGet());
        executor2.addShutdownListener(() -> counter2.incrementAndGet());

        executor1.shutdown();
        assertEquals(1, counter1.get());
        assertEquals(0, counter2.get());

        executor2.shutdown();

    public void test_concurrent_stores() {
        // Test thread-safe implementation
        final AtomicLong counter = new AtomicLong(0);

        IndexUpdateCallback callback = new IndexUpdateCallback() {
            @Override
            public void store(DataStoreParams paramMap, Map<String, Object> dataMap) {
                counter.incrementAndGet();
            }

            @Override
            public long getDocumentSize() {

     * and the counter returned by {@link #totalProblemsReported()} are not equal (latter is bigger than former).
     *
     * @return true if the problem collector has overflowed and some problems were not preserved
     */
    boolean problemsOverflow();

    /**
     * Reports a problem: always maintains the counters, but whether problem is preserved in memory, depends on

   * Multiple threads using same array of counters successfully update a number of times equal to
   * total count
   */
  public void testCountingInMultipleThreads() throws InterruptedException {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);
    for (int i = 0; i < SIZE; i++) {
      aa.set(i, (double) COUNTDOWN);
    }
    Counter c1 = new Counter(aa);
    Counter c2 = new Counter(aa);
    Thread t1 = newStartedThread(c1);

        long currentWindow = System.currentTimeMillis() / rateLimitWindow;
        String windowKey = key + "_" + currentWindow;

        AtomicLong counter = rateLimitCounters.computeIfAbsent(windowKey, k -> new AtomicLong(0));
        long currentCount = counter.incrementAndGet();

        // Clean up old windows periodically
        if (currentCount == 1) {
            cleanupOldRateLimitCounters(currentWindow);
        }

| `minio_api_requests_rejected_header_total`     | Total number of requests rejected for invalid header. <br><br>Type: counter    | `type`, `pool_index`, `server`               |
| `minio_api_requests_rejected_timestamp_total`  | Total number of requests rejected for invalid timestamp. <br><br>Type: counter | `type`, `pool_index`, `server`               |

	return handler
}

// registerAPIRouter - registers S3 compatible APIs.
func registerAPIRouter(router *mux.Router) {
	// Initialize API.
	api := objectAPIHandlers{
		ObjectAPI: newObjectLayerFn,
	}

	// API Router
	apiRouter := router.PathPrefix(SlashSeparator).Subrouter()

	var routers []*mux.Router
	for _, domainName := range globalDomainNames {
		if IsKubernetes() {

This is different from using an `APIRouter` as a mounted application is completely independent. The OpenAPI and docs from your main application won't include anything from the mounted application, etc.

You can read more about this in the [Advanced User Guide](../advanced/index.md){.internal-link target=_blank}.

## Details { #details }