After a recent change ( JDK-8171380), there is a a warning during compilation of the ModuleSummary build tool:

 warning: [options] module name in --add-exports option not found: jdk.jdeps

It can be seen from the history of ModuleSummary.java in jake that at one point this class used types from com.sun.tools.classfile ( in the jdeps module ), but no longer does. The add exports can simply be removed, as it it not needed any more.

diff --git a/make/ModuleTools.gmk b/make/ModuleTools.gmk
--- a/make/ModuleTools.gmk
+++ b/make/ModuleTools.gmk
@@ -39,7 +39,6 @@
    build.tools.jigsaw.GenGraphs

TOOL_MODULESUMMARY := $(BUILD_JAVA) -esa -ea -cp $(TOOLS_CLASSES_DIR) \
- --add-exports jdk.jdeps/com.sun.tools.classfile=ALL-UNNAMED \
    build.tools.jigsaw.ModuleSummary

TOOL_ADD_PACKAGES_ATTRIBUTE := $(BUILD_JAVA) $(JAVA_FLAGS_SMALL) \