add JDK 9 support

.java-version

@@ -0,0 +1 @@
+1.8

build.sbt

@@ -105,7 +105,11 @@ val root = (project in file(".")).
     // Universal ZIP download install.
     packageName in Universal := packageName.value, // needs to be set explicitly due to a bug in native-packager
     version in Universal := sbtVersionToRelease,
-    mappings in Universal <+= sbtLaunchJar map { _ -> "bin/sbt-launch.jar" },
+    mappings in Universal ++= {
+      val launchJar = sbtLaunchJar.value
+      val rtExportJar = (packageBin in Compile in java9rtexport).value
+      Seq(launchJar -> "bin/sbt-launch.jar", rtExportJar -> "bin/java9-rt-export.jar")
+    },
 
     // Misccelaneous publishing stuff...
     projectID in Debian    <<= moduleID,
@@ -117,6 +121,18 @@ val root = (project in file(".")).
     projectID in Universal <<= moduleID
   )
 
+lazy val java9rtexport = (project in file("java9-rt-export"))
+  .settings(
+    name := "java9-rt-export",
+    autoScalaLibrary := false,
+    crossPaths := false,
+    description := "Exports the contents of the Java 9. JEP-220 runtime image to a JAR for compatibility with older tools.",
+    homepage := Some(url("http://github.com/retronym/" + name.value)),
+    startYear := Some(2017),
+    licenses += ("Scala license", url(homepage.value.get.toString + "/blob/master/LICENSE")),
+    mainClass in Compile := Some("io.github.retronym.java9rtexport.Export")
+  )
+
 def downloadUrlForVersion(v: String) = (v split "[^\\d]" flatMap (i => catching(classOf[Exception]) opt (i.toInt))) match {
   case Array(0, 11, 3, _*)           => "http://repo.typesafe.com/typesafe/ivy-releases/org.scala-sbt/sbt-launch/0.11.3-2/sbt-launch.jar"
   case Array(0, 11, x, _*) if x >= 3 => "http://repo.typesafe.com/typesafe/ivy-releases/org.scala-sbt/sbt-launch/"+v+"/sbt-launch.jar"

java9-rt-export/src/main/java/io/github/retronym/java9rtexport/Copy.java

@@ -0,0 +1,49 @@
+package io.github.retronym.java9rtexport;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.file.*;
+import java.nio.file.attribute.*;
+import java.util.EnumSet;
+
+import static java.nio.file.StandardCopyOption.COPY_ATTRIBUTES;
+import static java.nio.file.StandardCopyOption.REPLACE_EXISTING;
+
+public class Copy {
+    public static void copyDirectory(final Path source, final Path target)
+            throws IOException {
+        Files.walkFileTree(source, EnumSet.of(FileVisitOption.FOLLOW_LINKS),
+                Integer.MAX_VALUE, new FileVisitor<Path>() {
+
+                    @Override
+                    public FileVisitResult preVisitDirectory(Path dir,
+                                                             BasicFileAttributes sourceBasic) throws IOException {
+
+                        String relative = source.relativize(dir).toString();
+                        if (!Files.exists(target.getFileSystem().getPath(relative)))
+                            Files.createDirectory(target.getFileSystem().getPath(relative));
+                        return FileVisitResult.CONTINUE;
+                    }
+
+                    @Override
+                    public FileVisitResult visitFile(Path file,
+                                                     BasicFileAttributes attrs) throws IOException {
+                        String relative = source.relativize(file).toString();
+                        Files.copy(file, target.getFileSystem().getPath(relative), COPY_ATTRIBUTES, REPLACE_EXISTING);
+                        return FileVisitResult.CONTINUE;
+                    }
+
+                    @Override
+                    public FileVisitResult visitFileFailed(Path file, IOException e) throws IOException {
+                        throw e;
+                    }
+
+                    @Override
+                    public FileVisitResult postVisitDirectory(Path dir, IOException e) throws IOException {
+                        if (e != null) throw e;
+                        return FileVisitResult.CONTINUE;
+                    }
+                });
+    }
+
+}

java9-rt-export/src/main/java/io/github/retronym/java9rtexport/Export.java

@@ -0,0 +1,48 @@
+package io.github.retronym.java9rtexport;
+
+import java.io.IOException;
+import java.net.URI;
+import java.nio.file.*;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+
+public class Export {
+    public static void main(String[] args) {
+        try {
+
+            if (args.length == 0) {
+                System.err.println("Usage:");
+                System.err.println("    java -jar java9-rt-export-*.jar $HOME/.sbt/java9-rt-ext/rt.jar");
+                System.err.println("        Exports rt.jar to the specified path.");
+                System.err.println("");
+                System.err.println("    java -jar java9-rt-export-*.jar --global-base");
+                System.err.println("        Prints sbt global base.");
+                System.exit(-1);
+            }
+            String destination = args[0];
+            if (destination.equals("--global-base")) {
+                Path defaultGlobalBase = Paths.get(System.getProperty("user.home"), ".sbt", "0.13");
+                String globalBase = System.getProperty("sbt.global.base", defaultGlobalBase.toString());
+                System.out.println(globalBase);
+                System.exit(0);
+            }
+            FileSystem fileSystem = FileSystems.getFileSystem(URI.create("jrt:/"));
+            Path path = fileSystem.getPath("/modules");
+            Path destPath = Paths.get(destination);
+            URI uri = URI.create( "jar:" + destPath.toUri() );
+            Map<String, String> env = new HashMap<>();
+            env.put( "create", "true" );
+            try ( FileSystem zipfs = FileSystems.newFileSystem( uri, env ) ) {
+                Iterator<Path> iterator = Files.list(path).iterator();
+                while(iterator.hasNext()) {
+                    Path next = iterator.next();
+                    Copy.copyDirectory(next, zipfs.getPath("/"));
+                }
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+            System.exit(-1);
+        }
+    }
+}

src/universal/bin/sbt-launch-lib.bash

@@ -38,6 +38,10 @@ acquire_sbt_jar () {
   fi
 }
 
+rt_export_file () {
+  echo "${sbt_bin_dir}/java9-rt-export.jar"
+}
+
 execRunner () {
   # print the arguments one to a line, quoting any containing spaces
   [[ $verbose || $debug ]] && echo "# Executing command line:" && {
@@ -147,8 +151,16 @@ process_args () {
     process_my_args "${myargs[@]}"
   }
 
-  java_version=$("$java_cmd" -Xmx512M -version 2>&1 | sed 's/.*version "\([0-9]*\)\.\([0-9]*\)\..*"/\1.\2/; 1q')
+  ## parses 1.7, 1.8, 9, etc out of java version "1.8.0_91"
+  java_version=$("$java_cmd" -Xmx512M -version 2>&1 | sed 's/.*version "\([0-9]*\)\(\.[0-9]*\)\{0,1\}\(.*\)*"/\1\2/; 1q')
   vlog "[process_args] java_version = '$java_version'"
+  rtexport=$(rt_export_file)
+  sbt_global_dir=$("$java_cmd" ${JAVA_OPTS} ${SBT_OPTS:-$default_sbt_opts} ${java_args[@]} \
+    -jar "$rtexport" --global-base)
+  java9_ext=$(echo "$sbt_global_dir/java9-rt-ext")
+  java9_rt=$(echo "$java9_ext/rt.jar")
+  vlog "[process_args] sbt_global_dir = '$sbt_global_dir'"
+  vlog "[process_args] java9_rt = '$java9_rt'"
 }
 
 # Detect that we have java installed.
@@ -174,6 +186,21 @@ checkJava() {
   fi
 }
 
+copyRt() {
+  if [[ "$java_version" > "8" ]] && [[ ! -f "$java9_rt" ]]; then
+    echo Copying runtime jar.
+    execRunner "$java_cmd" \
+      ${JAVA_OPTS} \
+      ${SBT_OPTS:-$default_sbt_opts} \
+      ${java_args[@]} \
+      -jar "$rtexport" \
+      "${java9_rt}"
+  fi
+  if [[ "$java_version" > "8" ]]; then
+    addJava "-Dscala.ext.dirs=${java9_ext}"
+  fi
+}
+
 
 run() {
   # no jar? download it.
@@ -191,6 +218,9 @@ run() {
   # TODO - java check should be configurable...
   checkJava "1.6"
 
+  # Java 9 support
+  copyRt
+
   #If we're in cygwin, we should use the windows config, and terminal hacks
   if [[ "$CYGWIN_FLAG" == "true" ]]; then
     stty -icanon min 1 -echo > /dev/null 2>&1