src/java.base/windows/classes/sun/nio/ch/DefaultPollerProvider.java

*** 28,15 ***
  
  /**
   * Default PollerProvider for Windows based on wepoll.
   */
  class DefaultPollerProvider extends PollerProvider {
!     DefaultPollerProvider() { }
  
      @Override
!     int defaultReadPollers(Poller.Mode mode) {
-         assert mode == Poller.Mode.SYSTEM_THREADS;
          int ncpus = Runtime.getRuntime().availableProcessors();
          return Math.max(Integer.highestOneBit(ncpus / 8), 1);
      }
  
      @Override
--- 28,23 ---
  
  /**
   * Default PollerProvider for Windows based on wepoll.
   */
  class DefaultPollerProvider extends PollerProvider {
!     DefaultPollerProvider(Poller.Mode mode) {
+         if (mode != Poller.Mode.SYSTEM_THREADS) {
+             throw new UnsupportedOperationException();
+         }
+         super(mode);
+     }
+ 
+     DefaultPollerProvider() {
+         this(Poller.Mode.SYSTEM_THREADS);
+     }
  
      @Override
!     int defaultReadPollers() {
          int ncpus = Runtime.getRuntime().availableProcessors();
          return Math.max(Integer.highestOneBit(ncpus / 8), 1);
      }
  
      @Override

*** 44,15 ***
          return (fdVal >> 2) & (toIndex - 1);
      }
  
      @Override
      Poller readPoller(boolean subPoller) throws IOException {
!         assert !subPoller;
          return new WEPollPoller(true);
      }
  
      @Override
      Poller writePoller(boolean subPoller) throws IOException {
!         assert !subPoller;
          return new WEPollPoller(false);
      }
  }
--- 52,17 ---
          return (fdVal >> 2) & (toIndex - 1);
      }
  
      @Override
      Poller readPoller(boolean subPoller) throws IOException {
!         if (subPoller)
+             throw new UnsupportedOperationException();
          return new WEPollPoller(true);
      }
  
      @Override
      Poller writePoller(boolean subPoller) throws IOException {
!         if (subPoller)
+             throw new UnsupportedOperationException();
          return new WEPollPoller(false);
      }
  }