output: #fixed code
                                  @Override
      protected void processEvents(int readyCount) throws IOReactorException {
          processSessionRequests();
          
          if (readyCount > 0) {
              Set<SelectionKey> selectedKeys = this.selector.selectedKeys();
              for (Iterator<SelectionKey> it = selectedKeys.iterator(); it.hasNext(); ) {
                  
                  SelectionKey key = it.next();
                  processEvent(key);
                  
              }
              selectedKeys.clear();
          }
          
          long currentTime = System.currentTimeMillis();
          if ((currentTime - this.lastTimeoutCheck) >= this.selectTimeout) {
              this.lastTimeoutCheck = currentTime;
              Set<SelectionKey> keys = this.selector.keys();
              processTimeouts(keys);
          }
      }
input: #vulnerable code 
                                  @Override
      protected void processEvents(int readyCount) throws IOReactorException {
          processSessionRequests();
          
          if (readyCount > 0) {
              Set<SelectionKey> selectedKeys = this.selector.selectedKeys();
              for (Iterator<SelectionKey> it = selectedKeys.iterator(); it.hasNext(); ) {
                  
                  SelectionKey key = it.next();
                  processEvent(key);
                  
              }
              selectedKeys.clear();
          }
          
          long currentTime = System.currentTimeMillis();
          if ((currentTime - this.lastTimeoutCheck) >= this.selectTimeout) {
              this.lastTimeoutCheck = currentTime;
              Set<SelectionKey> keys = this.selector.keys();
              synchronized (keys) {
                  processTimeouts(keys);
              }
          }
      } 
                              #location 10 
                              #vulnerability type THREAD_SAFETY_VIOLATION