8303481: CancelRequestTest assertTrue failing with AssertionError due to java.util.concurrent.CompletionException: java.io.EOFException: EOF reached while reading

Reviewed-by: jpai, djelinski

src/java.net.http/share/classes/jdk/internal/net/http/frame/OutgoingHeaders.java

@@ -80,4 +80,8 @@ public class OutgoingHeaders<T> extends Http2Frame {
         return system;
     }
 
+    @Override
+    public String toString() {
+        return "OutgoingHeaders()";
+    }
 }

test/jdk/java/net/httpclient/lib/jdk/httpclient/test/lib/http2/Http2TestServerConnection.java

@@ -828,7 +828,10 @@ public class Http2TestServerConnection {
                                 throw new IOException("Unexpected frame");
                             }
                         } else {
-                            q.put(frame);
+                            if (!q.putIfOpen(frame)) {
+                                System.err.printf("Stream %s is closed: dropping %s%n",
+                                        stream, frame);
+                            }
                         }
                     }
                 }

test/jdk/java/net/httpclient/lib/jdk/httpclient/test/lib/http2/Queue.java

@@ -58,17 +58,24 @@ public class Queue<T> implements ExceptionallyCloseable {
         return closing;
     }
 
+    public synchronized boolean isOpen() {
+        return !closed && !closing;
+    }
+
     public synchronized void put(T obj) throws IOException {
-        Objects.requireNonNull(obj);
-        if (closed || closing) {
+        if (!putIfOpen(obj)) {
             throw new IOException("stream closed");
         }
+    }
 
+    public synchronized boolean putIfOpen(T obj) {
+        Objects.requireNonNull(obj);
+        if (!isOpen()) return false;
         q.add(obj);
-
         if (waiters > 0) {
             notifyAll();
         }
+        return true;
     }
 
     // Other close() variants are immediate and abortive