From 0b77d7d5023eb7afb4aeb1483a9f687a676f3ed8 Mon Sep 17 00:00:00 2001
From: Federico Bond <federicobond@gmail.com>
Date: Sat, 2 Aug 2014 20:32:59 -0300
Subject: [PATCH] Synchronize initialization of ContributionListing singleton

---
 app/src/processing/app/contrib/ContributionListing.java | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/app/src/processing/app/contrib/ContributionListing.java b/app/src/processing/app/contrib/ContributionListing.java
index 8ad8df331..d79961e75 100644
--- a/app/src/processing/app/contrib/ContributionListing.java
+++ b/app/src/processing/app/contrib/ContributionListing.java
@@ -36,7 +36,7 @@ public class ContributionListing {
   static final String LISTING_URL =
     "http://download.processing.org/contributions.txt";
 
-  static ContributionListing singleInstance;
+  static volatile ContributionListing singleInstance;
 
   File listingFile;
   ArrayList<ContributionChangeListener> listeners;
@@ -64,7 +64,11 @@ public class ContributionListing {
 
   static ContributionListing getInstance() {
     if (singleInstance == null) {
-      singleInstance = new ContributionListing();
+      synchronized (ContributionListing.class) {
+        if (singleInstance == null) {
+          singleInstance = new ContributionListing();
+        }
+      }
     }
     return singleInstance;
   }