// compile JavaX source, load classes & return main class
  // src can be a snippet ID or actual source code
  
  // requires class _javax
  
  static Class<?> hotwire(String src) {
    try {
      try { _javax.androidContext = get(main.class, "androidContext"); } catch (Exception e) {}
      
      List<File> libraries = new ArrayList<File>();
      File srcDir = _javax.transpileMain(src, libraries);
      
      if (_javax.androidContext != null)
        return _javax.loadx2android(srcDir, src);
        
      File classesDir = _javax.TempDirMaker_make();
      String javacOutput = _javax.compileJava(srcDir, libraries, classesDir);
      System.out.println(javacOutput);
      
      URL[] urls = new URL[libraries.size()+1];
      urls[0] = classesDir.toURI().toURL();
      for (int i = 0; i < libraries.size(); i++)
        urls[i+1] = libraries.get(i).toURI().toURL();

      // make class loader
      URLClassLoader classLoader = new URLClassLoader(urls);
  
      // load & return main class
      Class<?> theClass = classLoader.loadClass("main");
      
      if (isSnippetID(src))
        try {
          set(theClass, "programID", src);
        } catch (Throwable e) {}
      
      return theClass;
    } catch (Exception e) {
      throw e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e);
    }
  }

Began life as a copy of #1000401