The Brainpool curves are defined in RFC 5639, and was introduced in JDK 11 with JDK-7007966.  At that time the implementation was native code based. As there were some known security challenges, brainpool curves were deprecated in JDK 14 with JDK-8234924 and the implementation was removed with JDK-8235710 in JDK 16.

However, Brainpool curves have been used in practice.  There are voices[1][2] to add them back. 

[1]: https://mail.openjdk.org/pipermail/security-dev/2022-December/033839.html
[2]: https://mail.openjdk.org/pipermail/security-dev/2022-November/033428.html