Index: trunk/src/org/openstreetmap/josm/gui/mappaint/styleelement/StyleElement.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/mappaint/styleelement/StyleElement.java	(revision 16962)
+++ trunk/src/org/openstreetmap/josm/gui/mappaint/styleelement/StyleElement.java	(revision 16963)
@@ -3,7 +3,7 @@
 
 import java.awt.Font;
-import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.openstreetmap.josm.data.osm.IPrimitive;
@@ -197,5 +197,5 @@
     }
 
-    private static final Map<FontDescriptor, Font> FONT_MAP = new HashMap<>();
+    private static final Map<FontDescriptor, Font> FONT_MAP = new ConcurrentHashMap<>();
 
     private static Font getCachedFont(String name, int style, int size) {