Index: /trunk/src/org/openstreetmap/josm/io/OsmApi.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/OsmApi.java	(revision 5083)
+++ /trunk/src/org/openstreetmap/josm/io/OsmApi.java	(revision 5084)
@@ -567,4 +567,6 @@
                 System.out.print(requestMethod + " " + url + "... ");
                 activeConnection = (HttpURLConnection)url.openConnection();
+                // fix #5369, see http://www.tikalk.com/java/forums/httpurlconnection-disable-keep-alive
+                activeConnection.setRequestProperty("Connection", "close");
                 activeConnection.setConnectTimeout(fastFail ? 1000 : Main.pref.getInteger("socket.timeout.connect",15)*1000);
                 if (fastFail) {