From c7da1c4efd2c6d5f6e0fc9338c9cd309b7ca9ae9 Mon Sep 17 00:00:00 2001
From: Kirill Vainer <shadowislord@gmail.com>
Date: Wed, 2 Mar 2016 13:44:12 -0500
Subject: [PATCH] desktop: don't show dialogs when headless

---
 .../com/jme3/system/JmeDesktopSystem.java     | 20 +++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/jme3-desktop/src/main/java/com/jme3/system/JmeDesktopSystem.java b/jme3-desktop/src/main/java/com/jme3/system/JmeDesktopSystem.java
index 37a01e8ed..4fcfa17d5 100644
--- a/jme3-desktop/src/main/java/com/jme3/system/JmeDesktopSystem.java
+++ b/jme3-desktop/src/main/java/com/jme3/system/JmeDesktopSystem.java
@@ -43,6 +43,7 @@ import com.jme3.system.JmeContext.Type;
 import com.jme3.util.Screenshots;
 import java.awt.EventQueue;
 import java.awt.Graphics2D;
+import java.awt.GraphicsEnvironment;
 import java.awt.RenderingHints;
 import java.awt.geom.AffineTransform;
 import java.awt.image.AffineTransformOp;
@@ -116,12 +117,16 @@ public class JmeDesktopSystem extends JmeSystemDelegate {
 
     @Override
     public void showErrorDialog(String message) {
-        final String msg = message;
-        EventQueue.invokeLater(new Runnable() {
-            public void run() {
-                ErrorDialog.showDialog(msg);
-            }
-        });
+        if (!GraphicsEnvironment.isHeadless()) {
+            final String msg = message;
+            EventQueue.invokeLater(new Runnable() {
+                public void run() {
+                    ErrorDialog.showDialog(msg);
+                }
+            });
+        } else {
+            System.err.println("[JME ERROR] " + message);
+        }
     }
 
     @Override
@@ -129,6 +134,9 @@ public class JmeDesktopSystem extends JmeSystemDelegate {
         if (SwingUtilities.isEventDispatchThread()) {
             throw new IllegalStateException("Cannot run from EDT");
         }
+        if (GraphicsEnvironment.isHeadless()) {
+            throw new IllegalStateException("Cannot show dialog in headless environment");
+        }
 
         final AppSettings settings = new AppSettings(false);
         settings.copyFrom(sourceSettings);