Stanley Raymond Roring posted numerous threats on Facebook against Crafton Hills College in Yucaipa. He claimed to be plotting a Virginia Tech-style massacre.
In 2007, 33 people were killed by a gunman at Virginia Tech.
Roring pleaded guilty to making criminal threats. He was sentenced to six months in jail as part of a plea deal. He was given credit for 103 days already served. The remaining time will be served in a work-release program.
The Associated Press contributed to this report.