From 91afec43a67da5ae5862ea4b2a9aeaf131aaf07e Mon Sep 17 00:00:00 2001
From: Tony Tam <fehguy@gmail.com>
Date: Thu, 22 Oct 2015 15:43:02 -0700
Subject: [PATCH] fixed NPE on empty props

---
 .../main/java/io/swagger/codegen/plugin/CodeGenMojo.java   | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/modules/swagger-codegen-maven-plugin/src/main/java/io/swagger/codegen/plugin/CodeGenMojo.java b/modules/swagger-codegen-maven-plugin/src/main/java/io/swagger/codegen/plugin/CodeGenMojo.java
index 805afe22a94..22726c84c04 100644
--- a/modules/swagger-codegen-maven-plugin/src/main/java/io/swagger/codegen/plugin/CodeGenMojo.java
+++ b/modules/swagger-codegen-maven-plugin/src/main/java/io/swagger/codegen/plugin/CodeGenMojo.java
@@ -131,7 +131,12 @@ public class CodeGenMojo extends AbstractMojo {
 
         if (environmentVariables != null) {
             for(String key : environmentVariables.keySet()) {
-                System.setProperty(key, environmentVariables.get(key));
+                String value = environmentVariables.get(key);
+                if(value == null) {
+                    // don't put null values
+                    value = "";
+                }
+                System.setProperty(key, value);
             }
         }