If you've got time, check out the full 62-page solution, it's a really nice read even if you're not a lawyer: https://www.supremecourt.gov/opinions/20pdf/18-956_d18f.pdf . Of course, it does not mean you (or me) understands it correctly. But it does contain everything you want, starting from background and some facts.
The main opinion and relevant facts are on pages 5-40. Dissenting opinion is on pages 44+. An interesting quote from there:
> Oracle spent years developing a programming library that successfully attracted software developers, thus enhancing the value of Oracle’s products[1]. Google sought a license to use the library in Android, the operating system it was developing for mobile phones. But when the companies could not agree on terms, Google simply copied verbatim 11,500 lines of code from the library. As a result, it erased 97.5% of the value of Oracle’s partnership with Amazon, made tens of billions of dollars, and established its position as the owner of the largest mobile operating system in the world. > ... > Oracle gave developers free access to these methods to encourage them to write programs for the Java platform. In return, developers were required to make their programs compatible with the Java platform on any device. Developers were encouraged to make improvements to the platform, but they were required to release beneficial modifications to the public. If a company wanted to customize the platform and keep those customizations secret for business purposes, it had to pay for a separate license.