output: #fixed code
                                  @Test
      public void bidiBackpressure() throws InterruptedException {
          RxNumbersGrpc.RxNumbersStub stub = RxNumbersGrpc.newRxStub(channel);
  
          Flowable<NumberProto.Number> rxRequest = Flowable
                  .fromIterable(IntStream.range(0, NUMBER_OF_STREAM_ELEMENTS)::iterator)
                  .doOnNext(i -> System.out.println(i + " --> "))
                  .doOnNext(i -> updateNumberOfWaits(clientLastValueTime, clientNbOfWaits))
                  .map(BackpressureIntegrationTest::protoNum);
  
          TestSubscriber<NumberProto.Number> rxResponse = stub.twoWayPressure(rxRequest)
                  .doOnNext(n -> System.out.println(n.getNumber(0) + "  <--"))
                  .doOnNext(n -> waitIfValuesAreEqual(n.getNumber(0), 3))
                  .test();
  
          rxResponse.awaitTerminalEvent(5, TimeUnit.SECONDS);
          rxResponse.assertComplete().assertValueCount(NUMBER_OF_STREAM_ELEMENTS);
  
          assertThat(clientNbOfWaits.get()).isEqualTo(1);
          assertThat(serverNumberOfWaits.get()).isEqualTo(1);
      }
input: #vulnerable code 
                                  @Test
      public void bidiBackpressure() throws InterruptedException {
          Object lock = new Object();
          BackpressureDetector clientReqBPDetector = new BackpressureDetector(madMultipleCutoff);
          BackpressureDetector clientRespBPDetector = new BackpressureDetector(madMultipleCutoff);
  
          RxNumbersGrpc.RxNumbersStub stub = RxNumbersGrpc.newRxStub(channel);
  
          Flowable<NumberProto.Number> rxRequest = Flowable
                  .fromIterable(new Sequence(180, clientReqBPDetector))
                  .doOnNext(i -> System.out.println(i + " -->"))
                  .map(BackpressureIntegrationTest::protoNum);
  
          Flowable<NumberProto.Number> rxResponse = stub.twoWayPressure(rxRequest);
  
          rxResponse.subscribe(
                  n -> {
                      clientRespBPDetector.tick();
                      System.out.println("               " + n.getNumber(0) + "  <--");
                      try { Thread.sleep(50); } catch (InterruptedException e) {}
                  },
                  t -> {
                      t.printStackTrace();
                      synchronized (lock) {
                          lock.notify();
                      }
                  },
                  () -> {
                      System.out.println("Client done.");
                      synchronized (lock) {
                          lock.notify();
                      }
                  });
  
          synchronized (lock) {
              lock.wait(TimeUnit.SECONDS.toMillis(20));
          }
  
          assertThat(clientReqBPDetector.backpressureDelayOcurred()).isTrue();
          assertThat(serverRespBPDetector.backpressureDelayOcurred()).isTrue();
      } 
                              #location 7 
                              #vulnerability type THREAD_SAFETY_VIOLATION