Public void upload(HttpServletRequest request) throws ServletException { MultipartHttpServletRequest mRequest = (MultipartHttpServletRequest) request; String next = (String) mRequest.getFileNames().next(); MultipartFile file = mRequest.getFile(next); if (file == null) return; if (fileName != null) { if (fileName.endsWith(".docx") || fileName.endsWith(".pptx") ||fileName.endsWith(".pdf") || fileName.endsWith(".xlsx")){ /* file upload routine*/ } else throw new ServletExeption("error"); JAVA String jarFile = "/download/util.jar"; Byte[] loadFile = FileManager.getBytes(jarFile); loadFile = encrypt(load File, privateKey); FileManager.createFile(load File, jarFileName); JAVA URL[] class URLs = new URL[] { new URL(http://filesave.com/download/util.jar)); URLConnection conn = class URLs.openConnection(); inputStream is = conn.getInputStream(); FileOutputStream fos = new FileOutputStream(new File(jarFile)); While(is.read(buf) !=-1){...} Byte[] loadFile = FileManager.getBytes(jarFile); loadFile = decrypt(loadFile, publicKey); FileManager.createFile(load File, jarFile); URLClassLoader loader = new URLClassLoader(class URLs); Class loaded Class = Class.forName("MyClass" true, loader); Public class FibonacciNumbers{ public int fibonacci(int n){ } return fibonacci(n - 1) + fibonacci(n-2); public static void main(String[] args){ JAVA FibonacciNumbers f = new FibonacciNumbers(); int x = f.fibonacci(10); System.out.println(x); }