diff --git a/src/Pure/Tools/scala_build.scala b/src/Pure/Tools/scala_build.scala
--- a/src/Pure/Tools/scala_build.scala
+++ b/src/Pure/Tools/scala_build.scala
@@ -1,70 +1,83 @@
 /*  Title:      Pure/Tools/scala_build.scala
     Author:     Makarius
 
 Manage and build Isabelle/Scala/Java components.
 */
 
 package isabelle
 
 
 import java.util.{Properties => JProperties}
 import java.nio.file.Files
 
 import scala.jdk.CollectionConverters._
 
 
 object Scala_Build
 {
   class Context private[Scala_Build](java_context: isabelle.setup.Build.Context)
   {
     override def toString: String = java_context.toString
 
     def is_module(path: Path): Boolean =
     {
       val module_name = java_context.module_name()
       module_name.nonEmpty && File.eq(java_context.path(module_name).toFile, path.file)
     }
 
     def sources: List[Path] =
       java_context.sources().asScala.toList.map(s => File.path(java_context.path(s).toFile))
 
     def requirements: List[Path] =
       (for {
         s <- java_context.requirements().asScala.iterator
         p <- java_context.requirement_paths(s).asScala.iterator
       } yield (File.path(p.toFile))).toList
 
     def build(fresh: Boolean = false): Unit =
       isabelle.setup.Build.build(java_context, fresh)
   }
 
   def context(dir: Path,
     component: Boolean = false,
+    no_title: Boolean = false,
     do_build: Boolean = false,
     module: Option[Path] = None): Context =
   {
     val props_name =
       if (component) isabelle.setup.Build.COMPONENT_BUILD_PROPS
       else isabelle.setup.Build.BUILD_PROPS
     val props_path = dir + Path.explode(props_name)
 
     val props = new JProperties
     props.load(Files.newBufferedReader(props_path.java_path))
+    if (no_title) props.remove(isabelle.setup.Build.TITLE)
     if (do_build) props.remove(isabelle.setup.Build.NO_BUILD)
     if (module.isDefined) props.put(isabelle.setup.Build.MODULE, File.standard_path(module.get))
 
     new Context(new isabelle.setup.Build.Context(dir.java_path, props, props_path.implode))
   }
 
   def build(dir: Path,
     fresh: Boolean = false,
     component: Boolean = false,
+    no_title: Boolean = false,
     do_build: Boolean = false,
     module: Option[Path] = None): Unit =
   {
-    context(dir, component = component, do_build = do_build, module = module).build(fresh = fresh)
+    context(dir, component = component, no_title = no_title, do_build = do_build, module = module)
+      .build(fresh = fresh)
+  }
+
+  def build_result(dir: Path, component: Boolean = false): Bytes =
+  {
+    Isabelle_System.with_tmp_file("result", "jar")(tmp_file =>
+    {
+      build(dir, component = component, no_title = true, do_build = true, module = Some(tmp_file))
+      Bytes.read(tmp_file)
+    })
   }
 
   def component_contexts(): List[Context] =
     isabelle.setup.Build.component_contexts().asScala.toList.map(new Context(_))
 }