Given it's a plugin on IntelliJ's marketplace, your best bet is to gain attention through the marketplace. Have nice screenshots, a video, explainers, etc.

1. For an IntelliJ plugin, the appropriate subreddits, discord channels, irc channels and so on (java, programming, etc).

2. You can of course share it here on HN.

3. Write about the project and try to soak in some organic traffic. Write about repetitive Java code, your solution, etc.