Justin Trudeau took a ribbing from his fellow Liberal leadership candidates at a debate in Mississauga Saturday.

One of the most aggressive exchanges came from former Ontario MP Martha Hall Findlay, who challenged Trudeau on his focus on the middle class.

She questioned what Trudeau knows about the middle class given his wealth, a challenge that drew some boos from the audience.

Trudeau said he's all about putting his privileged life into service for his country & giving back to Canadians.

Trudeau was also scrutinized by rival Marc Garneau.

The astronaut-turned-politician questioned Trudeau on his qualifications for the party's top job & accused him of using too many generalities when talking policy.

Trudeau stressed his ability to connect with people & said that's the key to leading the Liberals back to power.  He cited his success in winning his Montreal riding over the Bloc Québecois 2 elections ago.

Liberal leadership hopefuls will meet for 2 more debates.  The party will choose their next leader in April.

(With files from the Canadian Press)