Index: /trunk/build.xml
===================================================================
--- /trunk/build.xml	(revision 13504)
+++ /trunk/build.xml	(revision 13505)
@@ -9,5 +9,5 @@
 **
 -->
-<project xmlns:as="antlib:org.codehaus.mojo.animal_sniffer" name="josm" default="dist" xmlns:jacoco="antlib:org.jacoco.ant" xmlns:if="ant:if">
+<project xmlns:as="antlib:org.codehaus.mojo.animal_sniffer" name="josm" default="dist" xmlns:jacoco="antlib:org.jacoco.ant" xmlns:if="ant:if" xmlns:unless="ant:unless">
     <target name="init-properties">
         <!-- Load properties in a target and not at top level, so this build file can be
@@ -51,4 +51,8 @@
         <condition property="isJava10">
             <matches string="${ant.java.version}" pattern="1[0-9]" />
+        </condition>
+        <!-- For Java11-specific stuff -->
+        <condition property="isJava11">
+            <matches string="${ant.java.version}" pattern="1[1-9]" />
         </condition>
         <!-- Disable error_prone on Java 10+, see https://github.com/google/error-prone/issues/860 -->
@@ -477,6 +481,6 @@
                 <junit printsummary="yes" fork="true" forkmode="once">
                     <jvmarg value="-Dfile.encoding=UTF-8"/>
-                    <jvmarg value="--add-modules" if:set="isJava9" />
-                    <jvmarg value="java.activation,java.se.ee" if:set="isJava9" />
+                    <jvmarg value="--add-modules" if:set="isJava9" unless:set="isJava11" />
+                    <jvmarg value="java.activation,java.se.ee" if:set="isJava9" unless:set="isJava11" />
                     <jvmarg value="--add-exports" if:set="isJava9" />
                     <jvmarg value="java.base/sun.security.util=ALL-UNNAMED" if:set="isJava9" />