--- old/src/java.base/share/classes/sun/nio/ch/DatagramChannelImpl.java	2019-10-30 11:36:56.000000000 +0000
+++ new/src/java.base/share/classes/sun/nio/ch/DatagramChannelImpl.java	2019-10-30 11:36:56.000000000 +0000
@@ -404,6 +404,8 @@
 
     private SocketAddress sender;       // Set by receive0 (## ugh)
 
+    private static final int INITIAL = -100;  // some unambiguous negative value
+
     @Override
     public SocketAddress receive(ByteBuffer dst) throws IOException {
         if (dst.isReadOnly())
@@ -412,7 +414,7 @@
         readLock.lock();
         try {
             boolean blocking = isBlocking();
-            int n = 0;
+            int n = INITIAL;
             ByteBuffer bb = null;
             try {
                 SocketAddress remote = beginRead(blocking, false);
@@ -450,7 +452,7 @@
                         } catch (SecurityException se) {
                             // Ignore packet
                             bb.clear();
-                            n = 0;
+                            n = INITIAL;
                             continue;
                         }
                         bb.flip();
@@ -463,7 +465,7 @@
             } finally {
                 if (bb != null)
                     Util.releaseTemporaryDirectBuffer(bb);
-                endRead(blocking, n > 0);
+                endRead(blocking, n >= 0);
                 assert IOStatus.check(n);
             }
         } finally {