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Aliexpress and Udemy come right at the top of my mind. But there are quite a few more. (several German web-sites like Trivago). Spring Boot is used more outside the U.S. - Java is respected more in the rest of the world.

Most companies at that scale don't use a single framework or even language but there's probably more Spring at Amazon than RoR at GitHub, Stripe and Shopify combined.

Stripe doesn't use Ruby on Rails, they have a framework developed in house

I couldn't immediately locate it, but there was a famous example of an Amazon property leaking its Java stack trace but since I can't locate it I also can't swear it contained springframework classes

Pretty sure Netflix uses a ton of Spring.

It's one of the most common frameworks in the industry across languages.