A proposed enhancement, targeted for @ApacheGroovy version 6, adds an optional compile-time null checking mechanism.

𝑮𝒓𝒐𝒐𝒗𝒚'𝒔 𝒏𝒆𝒘 𝑵𝒖𝒍𝒍𝑪𝒉𝒆𝒄𝒌𝒆𝒓 𝒄𝒂𝒕𝒄𝒉𝒆𝒔 𝒚𝒐𝒖𝒓 𝑵𝒖𝒍𝒍𝑷𝒐𝒊𝒏𝒕𝒆𝒓𝑬𝒙𝒄𝒆𝒑𝒕𝒊𝒐𝒏𝒔 𝒂𝒕 𝒄𝒐𝒎𝒑𝒊𝒍𝒆 𝒕𝒊𝒎𝒆 — 𝒔𝒐 𝒚𝒐𝒖𝒓 𝒖𝒔𝒆𝒓𝒔 𝒅𝒐𝒏'𝒕 𝒉𝒂𝒗𝒆 𝒕𝒐 𝒇𝒊𝒏𝒅 𝒕𝒉𝒆𝒎 𝒂𝒕 𝒓𝒖𝒏𝒕𝒊𝒎𝒆.

Read more about it and provide your feedback:
https://groovy.apache.org/blog/groovy-null-checker
#groovylang @TheASF

The Apache Groovy programming language - Blogs - Compile-time null safety for Groovy™

This post looks at a proposed type-checking extension for Groovy which catches null-safety violations at compile time.