I've been setting up development environment using SpringSource Tool Suite (STS) and Oracle Enterprise Pack for Eclipse (OEPE).

I forgot to set up proxy in STS when I tried to download OEPE inside STS using eclipse update manager. No surprise, I got connection errors.

So I entered all the proxy settings and tried to download OEPE again. Nope, still not working. Why, was it because my proxy setting was wrong?

I wasted quite a bit of time checking the proxy setting with no result. Then after some digging, I found the solution.