Index: trunk/src/org/openstreetmap/josm/gui/util/GuiSizesHelper.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/util/GuiSizesHelper.java	(revision 10359)
+++ trunk/src/org/openstreetmap/josm/gui/util/GuiSizesHelper.java	(revision 10360)
@@ -2,4 +2,5 @@
 
 import java.awt.Dimension;
+import java.awt.HeadlessException;
 import java.awt.Toolkit;
 
@@ -21,5 +22,10 @@
             synchronized (GuiHelper.class) {
                 if (screenDPI == -1) {
-                    screenDPI = Toolkit.getDefaultToolkit().getScreenResolution();
+                    try {
+                        screenDPI = Toolkit.getDefaultToolkit().getScreenResolution();
+                    } catch (HeadlessException e) {
+                        screenDPI = 96;
+                    }
+                        
                 }
             }
@@ -35,5 +41,5 @@
     public static float getPixelDensity() {
         int pixelPerInch = getScreenDPI();
-        return (float) (pixelPerInch / 96.);
+        return (float) (pixelPerInch / 96.0);
     }