I was in US from June 2007 till Dec 2008 J-1 status trainee.
For my tax return, am I supposed to file 1040 or 1040 NR?
I thought I was NR but I find out my last year tax return was filed under 1040EZ. (My company HR did it for me) And I findout about the 183 days test and now I am confused if I should file under non resident or not.

You need to file Form 1040NR or 1040NR-EZ.

The filing of Form 1040EZ for 2007 was incorrect and should be amended using Form 1040X, with Form 1040NR-EZ attached.