Justices of the peace are judges who handle both civil and criminal cases, including small claims court, justice court, and administrative hearings. In practical terms, these are lawsuits over debts, evictions, car accidents, unlawful towing, and property.

Their criminal workload involves disposing of all class C criminal misdemeanor complaints, such as traffic citations, issuance of bad check, and others. These cases involve payment, setting contested cases for trial, and pretrial hearings with the county prosecutor.

Other duties include presiding over peace bond hearings, reviewing applications for mental health or chemically dependent commitments, conducting compulsory school attendance trials, and giving warnings to juveniles required by law. They issue warrants for and conduct hearings concerning seizure and disposition of cruelly treated animals. Most justices of the peace perform marriage ceremonies as well.

In New Jersey, the role described as 'justices of the peace' does not exist in the same form as in some other states. New Jersey's court system is structured differently, and the functions that might be associated with justices of the peace in other jurisdictions are carried out by different types of judges or judicial officers. Small claims matters are handled by the Small Claims division of the Special Civil Part of the Law Division of the New Jersey Superior Court. These courts handle civil cases involving amounts of $3,000 or less (or $5,000 for security deposit cases). Traffic citations and minor criminal offenses, which might be handled by justices of the peace elsewhere, are typically handled by Municipal Courts in New Jersey. These courts deal with matters such as traffic violations, minor criminal offenses, and municipal ordinance violations. Administrative hearings may be conducted by various administrative agencies or by Administrative Law Judges in the Office of Administrative Law. Marriage ceremonies can be performed by judges, mayors, and other officials authorized by the state. The duties related to mental health commitments are generally the purview of the Superior Court, particularly the Family Division, which handles cases involving family matters, including those related to mental health. Animal cruelty cases are also handled by the courts, with the involvement of local law enforcement and animal control agencies. Overall, the responsibilities described are distributed among different roles and courts within New Jersey's unified court system.