How can i convert the source code into an oxt file ?
Why bother? Can't you just use a daily build?
No brother i have added something extra to it and i have to know the procedure for converting it to a OXT file so that i could be able to test it...
This is documented at "How to build from source" at https://github.com/languagetool-org/languagetool/blob/master/README.md