What Java version are you migrating from exactly? Tbh JetBrains AI Assistant Subscription is decent because it maps your project graph properly before suggesting any changes.

@Reply #1 - good point! Saw this thread earlier and wanted to chime in. Im still pretty new to using AI in my workflow because honestly, I'm terrified of it breaking my builds. A few months ago I let an AI refactor a legacy Python script and it literally deleted a critical edge case check... had to stay up all night fixing it. For your legacy Java migration, you might want tools that are a bit more stable.

• Tabnine Pro Private AI Models: This is great because it has a local private code mode. It learns from your actual project patterns instead of just the open web. It doesnt hallucinate as much because its focused on your existing code patterns.
• JetBrains AI Assistant Pro Subscription: If you use IntelliJ for Java, this is decent. It feels more integrated with the actual IDE logic and deep static analysis than some of the generic plugins. Its not as flashy as some others but it feels safer for high-stakes migrations where you cant afford to break unit tests.

Honestly, standard Copilot can be pretty reckless with legacy Java. Since you have that $50 budget, i would suggest switching your main environment to Cursor AI Code Editor Pro which is $20 a month. It handles large context way better than the basic plugins. You should make sure to set the model to Anthropic Claude 3.5 Sonnet in the settings. Claude is much more cautious with logic and wont hallucinate weird boilerplate as often as GPT-4o does. Be careful with the codebase indexing tho... you need to let it finish scanning your whole repo before you start the migration tasks or the suggestions will be junk. You might also want to consider Sourcegraph Cody Pro Individual for another $9. It has a massive context window that helps when you're jumping between 10-year-old classes. Just verify everything manually, especially the decorators.