override def start()

in repl/scala-2.12/src/main/scala/org/apache/livy/repl/SparkInterpreter.scala [41:87]
38 lines of code
4 McCabe index (conditional complexity)

  override def start(): Unit = {
    require(sparkILoop == null)

    val rootDir = conf.get("spark.repl.classdir", System.getProperty("java.io.tmpdir"))
    val outputDir = Files.createTempDirectory(Paths.get(rootDir), "spark").toFile
    outputDir.deleteOnExit()
    conf.set("spark.repl.class.outputDir", outputDir.getAbsolutePath)

    val settings = new Settings()
    settings.processArguments(List("-Yrepl-class-based",
      "-Yrepl-outdir", s"${outputDir.getAbsolutePath}"), true)
    settings.usejavacp.value = true
    settings.embeddedDefaults(Thread.currentThread().getContextClassLoader())

    sparkILoop = new SparkILoop(None, new JPrintWriter(outputStream, true))
    sparkILoop.settings = settings
    sparkILoop.createInterpreter()
    sparkILoop.initializeSynchronous()

    restoreContextClassLoader {
      sparkILoop.compilerClasspath
      sparkILoop.ensureClassLoader
      var classLoader = Thread.currentThread().getContextClassLoader
      while (classLoader != null) {
        if (classLoader.getClass.getCanonicalName ==
          "org.apache.spark.util.MutableURLClassLoader") {
          val extraJarPath = classLoader.asInstanceOf[URLClassLoader].getURLs()
            // Check if the file exists. Otherwise an exception will be thrown.
            .filter { u => u.getProtocol == "file" && new File(u.getPath).isFile }
            // Livy rsc and repl are also in the extra jars list. Filter them out.
            .filterNot { u => Paths.get(u.toURI).getFileName.toString.startsWith("livy-") }
            // Some bad spark packages depend on the wrong version of scala-reflect. Blacklist it.
            .filterNot { u =>
              Paths.get(u.toURI).getFileName.toString.contains("org.scala-lang_scala-reflect")
            }

          extraJarPath.foreach { p => debug(s"Adding $p to Scala interpreter's class path...") }
          sparkILoop.addUrlsToClassPath(extraJarPath: _*)
          classLoader = null
        } else {
          classLoader = classLoader.getParent
        }
      }

      postStart()
    }
  }