diff -r b92aac38b046 -r 258033faefc9 src/jdk.dns.client/share/classes/jdk/dns/client/NetworkNamesResolver.java
--- a/src/jdk.dns.client/share/classes/jdk/dns/client/NetworkNamesResolver.java	Thu Nov 14 23:13:47 2019 +0000
+++ b/src/jdk.dns.client/share/classes/jdk/dns/client/NetworkNamesResolver.java	Thu Nov 14 23:16:40 2019 +0000
@@ -131,6 +131,9 @@
     public List<String> getAllHostsByAddr(InetAddress address) throws UnknownHostException {
         // First try hosts file
         // TODO: Add nsswitch.conf to select proper order
+        if (DEBUG) {
+            System.err.println("Resolver API: Reverse lookup call for address:"+address);
+        }
         try {
             return List.of(hostsFileResolver.getByAddress(address));
         } catch (UnknownHostException uhe) {