8038027: DTDBuilder should be run in headless mode
Reviewed-by: ihse, prr, tbell
Contributed-by: david.dehaven@oracle.com
diff --git a/make/Tools.gmk b/make/Tools.gmk
index aa61c1f..35ad809 100644
--- a/make/Tools.gmk
+++ b/make/Tools.gmk
@@ -80,6 +80,7 @@
     build.tools.generatecharacter.CharacterName
 
 TOOL_DTDBUILDER = $(JAVA) -Ddtd_home=$(JDK_TOPDIR)/make/data/dtdbuilder \
+    -Djava.awt.headless=true \
     -cp $(JDK_OUTPUTDIR)/btclasses build.tools.dtdbuilder.DTDBuilder
 
 TOOL_GENERATEBREAKITERATORDATA = $(JAVA) \