added component for javax mail;

--- a/etc/build.props	Wed Oct 25 17:06:21 2023 +0200
+++ b/etc/build.props	Thu Oct 26 11:23:53 2023 +0200
@@ -27,6 +27,7 @@
   src/Pure/Admin/component_foiltex.scala \
   src/Pure/Admin/component_fonts.scala \
   src/Pure/Admin/component_hugo.scala \
+  src/Pure/Admin/component_javamail.scala \
   src/Pure/Admin/component_jdk.scala \
   src/Pure/Admin/component_jedit.scala \
   src/Pure/Admin/component_jsoup.scala \

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/Admin/component_javamail.scala	Thu Oct 26 11:23:53 2023 +0200
@@ -0,0 +1,94 @@
+/*  Title:      Pure/Admin/component_javamail.scala
+    Author:     Fabian Huch, TU Muenchen
+
+Build Isabelle javax-mail component from official download. See also:
+
+  - https://javaee.github.io/javamail/
+  - https://mvnrepository.com/artifact/javax.mail/mail
+*/
+
+package isabelle
+
+
+object Component_Javamail {
+  /* build javamail */
+
+  val default_download_url =
+    "https://repo1.maven.org/maven2/javax/mail/mail/1.4.7/mail-1.4.7.jar"
+
+  def build_javamail(
+    download_url: String = default_download_url,
+    progress: Progress = new Progress,
+    target_dir: Path = Path.current
+  ): Unit = {
+    val Download_Name = """^.*/([^/]+)\.jar""".r
+    val download_name =
+      download_url match {
+        case Download_Name(download_name) => download_name
+        case _ => error("Malformed jar download URL: " + quote(download_url))
+      }
+    val component_name = "java" + download_name
+
+
+    /* component */
+
+    val component_dir =
+      Components.Directory(target_dir + Path.basic(component_name)).create(progress = progress)
+
+    File.write(component_dir.LICENSE,
+      Url.read("https://raw.githubusercontent.com/javaee/javamail/master/LICENSE.txt"))
+
+
+    /* README */
+
+    File.write(component_dir.README,
+      "This is " + component_name + " from\n" + download_url +
+        "\n\nSee also https://javaee.github.io/javamail and https://mvnrepository.com/artifact/javax.mail/mail" +
+        "\n\n        Fabian\n        " + Date.Format.date(Date.now()) + "\n")
+
+
+    /* settings */
+
+    component_dir.write_settings("""
+classpath "$COMPONENT/lib/""" + download_name + """.jar"
+""")
+
+
+    /* jar */
+
+    val jar = component_dir.lib + Path.basic(download_name).jar
+    Isabelle_System.make_directory(jar.dir)
+    Isabelle_System.download_file(download_url, jar, progress = progress)
+  }
+
+
+  /* Isabelle tool wrapper */
+
+  val isabelle_tool =
+    Isabelle_Tool("component_javamail", "build Isabelle javamail component from official download",
+      Scala_Project.here,
+      { args =>
+        var target_dir = Path.current
+        var download_url = default_download_url
+
+        val getopts = Getopts("""
+Usage: isabelle component_javamail [OPTIONS] DOWNLOAD
+
+  Options are:
+    -D DIR       target directory (default ".")
+    -U URL       download URL
+                 (default: """" + default_download_url + """")
+
+  Build javamail component from the specified download URL (JAR).
+""",
+          "D:" -> (arg => target_dir = Path.explode(arg)),
+          "U:" -> (arg => download_url = arg))
+
+        val more_args = getopts(args)
+        if (more_args.nonEmpty) getopts.usage()
+
+        val progress = new Console_Progress()
+
+        build_javamail(download_url = download_url, progress = progress, target_dir = target_dir)
+      })
+}

--- a/src/Pure/System/isabelle_tool.scala	Wed Oct 25 17:06:21 2023 +0200
+++ b/src/Pure/System/isabelle_tool.scala	Thu Oct 26 11:23:53 2023 +0200
@@ -171,6 +171,7 @@
   Component_Foiltex.isabelle_tool,
   Component_Fonts.isabelle_tool,
   Component_Hugo.isabelle_tool,
+  Component_Javamail.isabelle_tool,
   Component_JDK.isabelle_tool,
   Component_JEdit.isabelle_tool,
   Component_Jsoup.isabelle_tool,