diff --git a/src/Pure/Admin/build_sqlite.scala b/src/Pure/Admin/build_sqlite.scala
--- a/src/Pure/Admin/build_sqlite.scala
+++ b/src/Pure/Admin/build_sqlite.scala
@@ -1,109 +1,112 @@
 /*  Title:      Pure/Admin/build_sqlite.scala
     Author:     Makarius
 
 Build Isabelle sqlite-jdbc component from official download.
 */
 
 package isabelle
 
 
 object Build_SQLite {
   /* build sqlite */
 
+  val default_download_url =
+    "https://repo1.maven.org/maven2/org/xerial/sqlite-jdbc/3.36.0.3/sqlite-jdbc-3.36.0.3.jar"
+
   def build_sqlite(
-    download_url: String,
+    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))
       }
 
 
     /* component */
 
     val component_dir =
       Components.Directory.create(target_dir + Path.basic(download_name), progress = progress)
 
 
     /* README */
 
     File.write(component_dir.README,
       "This is " + download_name + " from\n" + download_url +
         "\n\n        Makarius\n        " + Date.Format.date(Date.now()) + "\n")
 
 
     /* settings */
 
     File.write(component_dir.settings,
 """# -*- shell-script -*- :mode=shellscript:
 
 ISABELLE_SQLITE_HOME="$COMPONENT"
 
 classpath "$ISABELLE_SQLITE_HOME/""" + download_name + """.jar"
 """)
 
 
     /* jar */
 
     val jar = component_dir.path + Path.basic(download_name).ext("jar")
     Isabelle_System.download_file(download_url, jar, progress = progress)
 
     Isabelle_System.with_tmp_dir("build") { jar_dir =>
       Isabelle_System.extract(jar, jar_dir)
 
       val jar_files =
         List(
           "META-INF/maven/org.xerial/sqlite-jdbc/LICENSE" -> ".",
           "META-INF/maven/org.xerial/sqlite-jdbc/LICENSE.zentus" -> ".",
           "org/sqlite/native/Linux/aarch64/libsqlitejdbc.so" -> "arm64-linux",
           "org/sqlite/native/Linux/x86_64/libsqlitejdbc.so" -> "x86_64-linux",
           "org/sqlite/native/Mac/aarch64/libsqlitejdbc.jnilib" -> "arm64-darwin",
           "org/sqlite/native/Mac/x86_64/libsqlitejdbc.jnilib" -> "x86_64-darwin",
           "org/sqlite/native/Windows/x86_64/sqlitejdbc.dll" -> "x86_64-windows")
 
       for ((file, dir) <- jar_files) {
         val target = Isabelle_System.make_directory(component_dir.path + Path.explode(dir))
         Isabelle_System.copy_file(jar_dir + Path.explode(file), target)
       }
 
       File.set_executable(component_dir.path + Path.explode("x86_64-windows/sqlitejdbc.dll"), true)
     }
   }
 
 
   /* Isabelle tool wrapper */
 
   val isabelle_tool =
     Isabelle_Tool("build_sqlite", "build Isabelle sqlite-jdbc component from official download",
       Scala_Project.here,
       { args =>
         var target_dir = Path.current
+        var download_url = default_download_url
 
         val getopts = Getopts("""
 Usage: isabelle build_sqlite [OPTIONS] DOWNLOAD
 
   Options are:
     -D DIR       target directory (default ".")
+    -U URL       download URL
+                 (default: """" + default_download_url + """")
 
   Build sqlite-jdbc component from the specified download URL (JAR), see also
   https://github.com/xerial/sqlite-jdbc and
   https://oss.sonatype.org/content/repositories/releases/org/xerial/sqlite-jdbc
 """,
-          "D:" -> (arg => target_dir = Path.explode(arg)))
+          "D:" -> (arg => target_dir = Path.explode(arg)),
+          "U:" -> (arg => download_url = arg))
 
         val more_args = getopts(args)
-        val download_url =
-          more_args match {
-            case List(download_url) => download_url
-            case _ => getopts.usage()
-          }
+        if (more_args.nonEmpty) getopts.usage()
 
         val progress = new Console_Progress()
 
-        build_sqlite(download_url, progress = progress, target_dir = target_dir)
+        build_sqlite(download_url = download_url, progress = progress, target_dir = target_dir)
       })
 }