--- old/make/UpdateX11Wrappers.gmk	2020-03-23 19:56:20.843962818 +0100
+++ new/make/UpdateX11Wrappers.gmk	2020-03-23 19:56:20.515962821 +0100
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2012, 2020, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -47,6 +47,9 @@
   $(error It is not possible to update the x11wrappers when cross-compiling)
 endif
 
+TOOL_WRAPPERGENERATOR = $(JAVA_SMALL) -cp $(BUILDTOOLS_OUTPUTDIR)/jdk_tools_classes \
+    org.openjdk.buildtools.x11wrappergen.WrapperGenerator
+
 X11WRAPPERS_OUTPUT := $(SUPPORT_OUTPUTDIR)/x11wrappers
 GENERATOR_SOURCE_FILE := $(X11WRAPPERS_OUTPUT)/src/data_generator.c