Index: trunk/build.xml
===================================================================
--- trunk/build.xml	(revision 12931)
+++ trunk/build.xml	(revision 12932)
@@ -151,5 +151,5 @@
                 <!-- Java 9 stuff. Entries are safely ignored by Java 8 -->
                 <attribute name="Add-Exports" value="java.base/sun.security.util java.base/sun.security.x509 java.desktop/com.apple.eawt java.desktop/com.sun.imageio.spi javafx.graphics/com.sun.javafx.application jdk.deploy/com.sun.deploy.config" />
-                <attribute name="Add-Opens" value="java.base/java.lang java.base/jdk.internal.loader java.desktop/javax.imageio.spi java.desktop/javax.swing.text.html java.prefs/java.util.prefs" />
+                <attribute name="Add-Opens" value="java.base/java.lang java.base/java.nio java.base/jdk.internal.loader java.base/jdk.internal.ref java.desktop/javax.imageio.spi java.desktop/javax.swing.text.html java.prefs/java.util.prefs" />
             </manifest>
             <service type="java.text.spi.DecimalFormatSymbolsProvider" provider="org.openstreetmap.josm.tools.JosmDecimalFormatSymbolsProvider" />
@@ -471,4 +471,6 @@
                     <jvmarg value="--add-opens" if:set="isJava9" />
                     <jvmarg value="java.base/java.lang=ALL-UNNAMED" if:set="isJava9" />
+                    <jvmarg value="--add-opens" if:set="isJava9" />
+                    <jvmarg value="java.base/java.nio=ALL-UNNAMED" if:set="isJava9" />
                     <jvmarg value="--add-opens" if:set="isJava9" />
                     <jvmarg value="java.base/java.text=ALL-UNNAMED" if:set="isJava9" />