searchCount.incrementAndGet();
                            Thread.sleep(10);
                        }
                    } catch (InterruptedException e) {
                        Thread.currentThread().interrupt();
                    }
                });

                // Thread 2: Register searchers
                executor.submit(() -> {
                    try {

  }

  @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
  static void awaitWaiting(Thread t) {
    while (true) {
      Thread.State state = t.getState();
      switch (state) {
        case RUNNABLE:
        case BLOCKED:
          Thread.yield();
          break;
        case WAITING:
          return;
        default:

    // Run a task on the composed Executor that interrupts its thread (i.e. this thread).
    fakePool.execute(() -> Thread.currentThread().interrupt());
    // Run a task that expects that it is not interrupted while it is running.
    e.execute(() -> assertThat(Thread.currentThread().isInterrupted()).isFalse());

    // Run these together.
    fakePool.runAll();

    void testConcurrentAccess() throws InterruptedException {
        // Test thread safety of getInstance
        LogStream.setInstance(testStream);

        final LogStream[] instances = new LogStream[10];
        Thread[] threads = new Thread[10];

        for (int i = 0; i < threads.length; i++) {
            final int index = i;
            threads[i] = new Thread(() -> {
                instances[index] = LogStream.getInstance();

        @DisplayName("Should maintain thread safety")
        void testThreadSafety() throws InterruptedException {
            int threadCount = 10;
            Thread[] threads = new Thread[threadCount];
            boolean[] success = new boolean[threadCount];

            for (int i = 0; i < threadCount; i++) {
                final int index = i;
                threads[i] = new Thread(() -> {
                    try {

            threads[i] = new Thread(() -> {
                byte[] threadFileId = new byte[16];
                Arrays.fill(threadFileId, (byte) index);
                request.setFileId(threadFileId);
            });
            threads[i].start();
        }

        // Wait for all threads to complete
        for (Thread thread : threads) {
            thread.join();
        }

        InputStreamThread thread = jobProcess.getInputStreamThread();
        thread.start();
        thread.join(1000);

        String output = thread.getOutput();
        assertTrue("Should contain recent lines", output.contains("line5"));

        assertTrue("Should have line3", thread.contains("line3"));
        assertTrue("Should have line4", thread.contains("line4"));

 * <p>
 * <strong>Thread-Safety:</strong> This class is <strong>NOT thread-safe</strong>.
 * It extends {@link LinkedHashMap} without synchronization. If multiple threads access
 * an instance concurrently, and at least one thread modifies the map structurally,
 * it must be synchronized externally.
 * </p>
 * <p>
 * For thread-safe usage, wrap with {@link java.util.Collections#synchronizedMap(Map)}:

                }
            });
        }

        // Start all threads
        for (Thread thread : threads) {
            thread.start();
        }

        // Wait for all threads to complete
        for (Thread thread : threads) {
            thread.join(5000); // 5 second timeout
        }

        // Verify no errors occurred during concurrent execution
        assertFalse(hasError.get());

          // thread.
          executionList.execute();
          return;
        }

        // TODO(lukes): handle RejectedExecutionException
        adapterExecutor.execute(
            () -> {
              try {
                /*
                 * Threads from our private pool are never interrupted. Threads from a