Last time I played with JHipster I thought it was really neat, but it couldn't readily be deployed to a free Heroku instance. The memory requirements were just too high even for a Hello, world app.
Yes we have had a lot of work with Heroku to make this work correctly. BTW, our Heroku sub-generator is made by Joe Kutner, the Heroku Java evangelist, so that's directly made by the person who knows this best!