Edward Furlong Sentenced to 6 Months in Jail

Hopefully "Terminator 2" star Edward Furlong is used to the food in jail by now -- because the actor was just sentenced to another 180 days behind bars for violating his probation.

Furlong -- who's been in and out of jail a slew of times over the past few years -- was sentenced Monday in L.A. Superior Court ... stemming from 2 probation violations:

1. Using force against his ex-GF Monica Keena -- for which he was arrested twice.
2. Violating a protective order, which stated he was to have NO CONTACT with Monica.

As TMZ previously reported, Furlong was placed on 3 years probation back in 2010 for violating a civil protective order obtained by his estranged wife Rachael Kneeland. Furlong was required to obey all laws during the course of his probation ...