Make the proguarded JAR directly runnable

build.sbt

@@ -337,15 +337,39 @@ lazy val addBootstrapJarAsResource = {
 }
 
 lazy val addBootstrapInProguardedJar = {
+
+  import java.nio.charset.StandardCharsets
+  import java.nio.file.Files
+
   ProguardKeys.proguard.in(Proguard) := {
     val bootstrapJar = packageBin.in(bootstrap).in(Compile).value
     val source = proguardedJar.value
 
     val dest = source.getParentFile / (source.getName.stripSuffix(".jar") + "-with-bootstrap.jar")
+    val dest0 = source.getParentFile / (source.getName.stripSuffix(".jar") + "-with-bootstrap-and-prelude.jar")
 
-    ZipUtil.addToZip(source, dest, Seq("bootstrap.jar" -> bootstrapJar))
+    // TODO Get from cli original JAR
+    val manifest =
+      s"""Manifest-Version: 1.0
+         |Implementation-Title: ${name.value}
+         |Implementation-Version: ${version.value}
+         |Specification-Vendor: ${organization.value}
+         |Specification-Title: ${name.value}
+         |Implementation-Vendor-Id: ${organization.value}
+         |Specification-Version: ${version.value}
+         |Implementation-URL: ${homepage.value.getOrElse("")}
+         |Implementation-Vendor: ${organization.value}
+         |Main-Class: ${mainClass.in(Compile).value.getOrElse(sys.error("Main class not found"))}
+         |""".stripMargin
 
-    Seq(dest)
+    ZipUtil.addToZip(source, dest, Seq(
+      "bootstrap.jar" -> Files.readAllBytes(bootstrapJar.toPath),
+      "META-INF/MANIFEST.MF" -> manifest.getBytes(StandardCharsets.UTF_8)
+    ))
+
+    ZipUtil.addPrelude(dest, dest0)
+
+    Seq(dest0)
   }
 }
 

project/ZipUtil.scala

@@ -1,10 +1,14 @@
 
-import java.util.zip.{ ZipEntry, ZipOutputStream, ZipInputStream }
-import java.io.{ ByteArrayOutputStream, FileInputStream, FileOutputStream, File, InputStream, IOException }
+import java.util.zip.{ZipEntry, ZipInputStream, ZipOutputStream}
+import java.io.{ByteArrayOutputStream, FileInputStream, FileOutputStream, InputStream}
+import java.nio.charset.StandardCharsets
+import java.nio.file.Files
+
+import sbt.File
 
 object ZipUtil {
 
-  def addToZip(sourceZip: File, destZip: File, extra: Seq[(String, File)]): Unit = {
+  def addToZip(sourceZip: File, destZip: File, extra: Seq[(String, Array[Byte])]): Unit = {
     
     val is = new FileInputStream(sourceZip)
     val os = new FileOutputStream(destZip)
@@ -50,9 +54,9 @@ object ZipUtil {
       outputZip.closeEntry()
     }
 
-    for ((dest, file) <- extra) {
+    for ((dest, data) <- extra) {
       outputZip.putNextEntry(new ZipEntry(dest))
-      outputZip.write(readFullySync(new FileInputStream(file)))
+      outputZip.write(data)
       outputZip.closeEntry()
     }
 
@@ -63,4 +67,21 @@ object ZipUtil {
 
   }
 
+  // seems the -noverify may not be needed anymore (to launch the proguarded JAR)
+  // not sure why
+  private val prelude =
+    """#!/usr/bin/env bash
+      |exec java -noverify -jar "$0" "$@"
+      |""".stripMargin
+
+  def addPrelude(source: File, dest: File): dest.type = {
+
+    val rawContent = Files.readAllBytes(source.toPath)
+    val content = prelude.getBytes(StandardCharsets.UTF_8) ++ rawContent
+
+    Files.write(dest.toPath, content)
+
+    dest
+  }
+
 }