code: public static <T> T executeWithClassLoader(ClassLoader classLoader,
                                               Callable<T> callable) throws Exception
    {
      ClassLoader previousClassLoader = Thread.currentThread().getContextClassLoader();
      try
      {
        Thread.currentThread().setContextClassLoader(classLoader);
        return callable.call();
      }
      finally
      {
        Thread.currentThread().setContextClassLoader(previousClassLoader);
      }
    }
docs: Execute the call within the given class loader... handle setting / reverting to
  previous class loader in a safe manner.
  
  @param classLoader the class loader to set for the duration of the call
  @param callable the callable to execute within the context of the provided class loader
  @return the result of the call
  @throws Exception whatever callable throws