src/java.base/share/classes/java/util/stream/AbstractPipeline.java

@@ -325,10 +325,12 @@
     }
 
     @Override
     @SuppressWarnings("unchecked")
     public S onClose(Runnable closeHandler) {
+        if (linkedOrConsumed)
+            throw new IllegalStateException(MSG_STREAM_LINKED);
         Objects.requireNonNull(closeHandler);
         Runnable existingHandler = sourceStage.sourceCloseAction;
         sourceStage.sourceCloseAction =
                 (existingHandler == null)
                 ? closeHandler