Young Jeezy -- I Knew I Was Innocent, So I Bought My Own Big House

Rapper Young Jeezy was so confident of beating the rap in his weapons case, he went and dropped a cool $1.5M on a fly new Georgia mansion ... a MONTH before learning his fate.

As TMZ first reported ... weapons charges were dismissed against the rapper last month in connection with a fatal shooting at a Wiz Khalifa concert. The case was weak ... in fact, it made no sense.

Jeezy was so confident of winning, he bought the Atlanta spread in November.

Jeezy should let his legal team crash anytime they want ... he's definitely got the space ... the 9,000 sq. ft. pad is a cavernous 6 bed/7bath paradise sitting on 1.2 acres.

The best part? If the cops ever come knocking again, they'll have to pass through his 600 lb cast iron front doors.

Solid.