Section 1. There shall be a trial court of the commonwealth which shall consist of the following departments: the superior court department, the housing court department, the land court department, the probate and family court department, the Boston municipal court department, the juvenile court department and district court department. The trial court, as an administrative unit, shall consist of no more than 384 justices and special justices. There shall be selected as herein provided, a chief justice of the trial court, a court administrator, a chief justice for each of the departments of the trial court and a deputy court administrator for each of the departments of the trial court.