diff --git a/core/src/main/java/hudson/EnvVars.java b/core/src/main/java/hudson/EnvVars.java
index 6204386c5119e4be0b5f27343f30e9bec741ae81..0070da51e1f12fdb9c6c8b74902b06589c4df3c4 100644
--- a/core/src/main/java/hudson/EnvVars.java
+++ b/core/src/main/java/hudson/EnvVars.java
@@ -226,7 +226,7 @@ public class EnvVars extends TreeMap<String,String> {
     private static EnvVars initMaster() {
         EnvVars vars = new EnvVars(System.getenv());
         vars.platform = Platform.current();
-        if(Main.isUnitTest)
+        if(Main.isUnitTest || Main.isDevelopmentMode)
             // if unit test is launched with maven debug switch,
             // we need to prevent forked Maven processes from seeing it, or else
             // they'll hang
diff --git a/core/src/main/java/hudson/Main.java b/core/src/main/java/hudson/Main.java
index 625f4df2ffeb93cecd441159681b5bf6f7a9a3d5..bdc00c48c1bd36be9b07898332d4b49b15b00da0 100644
--- a/core/src/main/java/hudson/Main.java
+++ b/core/src/main/java/hudson/Main.java
@@ -183,6 +183,11 @@ public class Main {
      */
     public static boolean isUnitTest = false;
 
+    /**
+     * Set to true if we are running inside "mvn hpi:run" or "mvn hudson-dev:run"
+     */
+    public static boolean isDevelopmentMode = Boolean.getBoolean(Main.class.getName()+".development");
+
     /**
      * Time out for socket connection to Hudson.
      */
diff --git a/war/pom.xml b/war/pom.xml
index eed0027748b9a33a549a559973d9c3b0b8a75755..f85a3bdbde63abd0a81737505d06f6569e1f5967 100644
--- a/war/pom.xml
+++ b/war/pom.xml
@@ -204,6 +204,10 @@ THE SOFTWARE.
               <name>hudson.model.UsageStatistics.disabled</name>
               <value>true</value>
             </systemProperty>
+            <systemProperty>
+              <name>hudson.Main.development</name>
+              <value>true</value>
+            </systemProperty>
           </systemProperties>
         </configuration>
       </plugin>