1 files changed, 9 insertions, 0 deletions
diff --git a/main/src/mill/Main.scala b/main/src/mill/Main.scala
index 0844e485..e026dfe0 100644
--- a/main/src/mill/Main.scala
+++ b/main/src/mill/Main.scala
@@ -5,6 +5,7 @@ import java.io.{InputStream, PrintStream}
 import ammonite.main.Cli._
 import ammonite.ops._
 import ammonite.util.Util
+import io.github.retronym.java9rtexport.Export
 import mill.eval.Evaluator
 import mill.util.DummyInputStream
 
@@ -118,6 +119,14 @@ object Main {
             stateCache
           )
 
+          if (mill.clientserver.ClientServer.isJava9OrAbove) {
+            val rt = cliConfig.home / Export.rtJarName
+            if (!exists(rt)) {
+              runner.printInfo(s"Preparing Java ${System.getProperty("java.version")} runtime; this may take a minute or two ...")
+              Export.rtTo(rt.toIO, false)
+            }
+          }
+
           if (repl){
             runner.printInfo("Loading...")
             (runner.watchLoop(isRepl = true, printing = false, _.run()), runner.stateCache)