It was about a year ago when James — who doesn't want his last name used so as not to jeopardize his employment — says he went to Dudley District Court to arrange paying off a criminal fine. When he told the judge he was poor, James says the judge determined that his payment plan would involve being immediately sent to the Worcester County House of Correction — where the 28-year-old learned that there was a term for his situation.

"I was introduced to the term because other inmates were familiar with it — it's called 'fine time,' " James explained, meaning going to jail if you can't pay your criminal fee. "Fine time means you're being imprisoned simply because you owe an outstanding fine to the state."

For every day James spent in jail, $30 was deducted from his fine. He was released when it was paid in full.

A preliminary analysis from a state Senate committee suggests that Massachusetts collected more than $30 million in probation and criminal fees in fiscal year 2015. Now some lawmakers are questioning whether the state is overly dependent on that money, and whether people are being jailed when they can't pay.

James will testify about his experience before the state Senate's Post Audit and Oversight Committee on Thursday. The committee's chair, Lexington state Sen. Michael Barrett, says lawmakers want to know if what happened to James is common.

"James is an extreme example of what can go wrong when you are too aggressive about collecting money from people who don't have any," Barrett said.

Barrett says his committee also wants to know if state courts are doing something that's unconstitutional.

"If we don't find some unexpected, exonerating circumstance, that is a case where the U.S. and state constitutions were violated and James was in prison for being poor only," Barrett said.

Criminal fines and fees should be part of the criminal justice reform debate currently raging across the country, Barrett says.

"The fact that we're making substantial money off people who have otherwise paid their debt to society and have no money, that's the troubling aspect of this broader question about criminal justice reform," Barrett said.

After Thursday's hearing, the committee will issue a written report about how the state is dealing — and should deal with — criminal fees and fines.