How to add java autocomplete feature?

I discovered theia on eclipse language server github page (

Since it is using, I expect it to autocomplete my java code but it is not completing for me.

I already built my theia following the “build your own ide” documentation. Should I add “@theia/java”: “next” to my package.json and make “yarn theia build” one more time? I have 1 gb ram on my machine so first “yarn theia build” command took 18 hours for me (I’m serious), so that’s why I wanted to ask before building again.

And also is it going to work like vscode redhat plugin? e.g. can it extract to variable using “Ctrl + .” command?

[original thread by valamorgon]

Hi @valamorgon . 1GB of RAM seems very low, to build even a small Theia-based application. You are right that you would need to add “@theia/java” to your package.json (next or latest, whichever you use for the other Theia extensions). You might consider building on a machine with more resources and moving the result on your more modest machine.


Hi @marc-dumais , thanks for confirmation. I’ll try to build again. I guess my machine will be like minimum system requirements tester. And do we have any usage documentation for java? Like shortcuts, extracting to variable etc.

@valamorgon we do not AFAIK have this documentation. You could use the keybindings view to discover available shortcuts.