i have 339361 rank in jee mains with general category .am i eligible for jossa councelling ?

Yes, you are eligible for jossa counseling, you just have to appear in jee main and must have alloted a rank.
At your rank i.e 339361 you are eligible for jossa counseling, but there are very rare chances that you'll be allotted a college, because you have a bit low rank but don't be disappointed, there are many colleges out there, and lots of counseling going too for admission to that colleges so keep up-to-date with counseling date and be confident. You can participate in your state counseling for admission to various colleges, also you can go for private colleges :-)
You must have mentioned your state so i can provide you various counseling related to your state and near by.
Best wishes for your future endeavors thank you.