From 9a39e5e6aca5fafd61e72dc65ac2bd9a76df8a42 Mon Sep 17 00:00:00 2001
From: Federico Fissore <f.fissore@arduino.cc>
Date: Fri, 4 Dec 2015 09:55:17 +0100
Subject: [PATCH] Some configuration may totally miss network interfaces, even
 localhost. Fixes #4249

---
 .../discoverers/network/NetworkChecker.java         | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arduino-core/src/cc/arduino/packages/discoverers/network/NetworkChecker.java b/arduino-core/src/cc/arduino/packages/discoverers/network/NetworkChecker.java
index 7b7dd3912..df58c220d 100644
--- a/arduino-core/src/cc/arduino/packages/discoverers/network/NetworkChecker.java
+++ b/arduino-core/src/cc/arduino/packages/discoverers/network/NetworkChecker.java
@@ -31,6 +31,8 @@ package cc.arduino.packages.discoverers.network;
 
 import javax.jmdns.NetworkTopologyDiscovery;
 import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
 import java.util.*;
 
 public class NetworkChecker extends TimerTask {
@@ -53,6 +55,9 @@ public class NetworkChecker extends TimerTask {
 
   @Override
   public void run() {
+    if (!hasNetworkInterfaces()) {
+      return;
+    }
     try {
       InetAddress[] curentAddresses = topology.getInetAddresses();
       Set<InetAddress> current = new HashSet<>(curentAddresses.length);
@@ -68,4 +73,12 @@ public class NetworkChecker extends TimerTask {
       e.printStackTrace();
     }
   }
+
+  private boolean hasNetworkInterfaces() {
+    try {
+      return NetworkInterface.getNetworkInterfaces() != null;
+    } catch (SocketException e) {
+      return false;
+    }
+  }
 }