Miami Heat star Udonis Haslem says the 2008 Boston Celtics are a bunch of petty whiners who need to GET OVER their beef with Ray Allen ... and he's not mincing his words. 

Of course, Allen famously left the Celtics after the '11-'12 season and joined up with the Miami Heat -- and guys like Paul Pierce, Kevin Garnett and Rajon Rondo are still upset he left without saying goodbye.

Haslem went on the "Joe Rose Show" on WQAM and said those guys need to grow up. He also took a moment to remind the guys the Miami Heat owned them during the height of the rivalry. 

"You got your ass whooped with Ray and we got Ray and we whooped your ass again."