Make sure to report EOF when reading from a socket channel

classpath/java-nio.cpp

@@ -271,6 +271,8 @@ Java_java_nio_channels_SocketChannel_natRead(JNIEnv *e,
     } else {
       throwIOException(e);
     }
+  } else if (r == 0) {
+    return -1;
   }
   return r;
 }

classpath/java/nio/channels/SocketChannel.java

@@ -44,6 +44,7 @@ public class SocketChannel extends SelectableChannel
   }
 
   public int read(ByteBuffer b) throws IOException {
+    if (! open) return -1;
     if (b.remaining() == 0) return 0;
     int r = natRead(socket, b.array(), b.arrayOffset() + b.position(), b.remaining());
     b.position(b.position() + r);