Manhattan Acting Supreme Court Justice Anil C. Singh heard oral arguments Wednesday in the fight over New York City’s plan to move some 44,000 criminal-defense cases annually from private, 18-B lawyers to institutional providers such as the Legal Aid Society.

A capacity crowd of defense attorneys and city lawyers filled Singh’s courtroom to watch the arguments on the merits of the Article 78 action and the city’s motion to dismiss. The suit, New York County Lawyers Association v. Bloomberg, 107216/10, was filed by five county bar associations earlier this year.