Bosnia and the International Court of Justice
It was the allegation of genocide that led Bosnia to sue Serbia in the International Court of Justice (ICJ). The case was officially called Bosnia and Herzegovina v. Serbia and Montenegro.

International Court of Justice resides in the Peace Palace, The Hague, The Netherlands

The main feature that distinguishes the ICJ from other courts, such as the International Criminal Court (ICC), is that at the ICJ only states can be parties to contentious cases. The ICC only tries individuals accused of various crimes (war crimes, crimes against humanity, and genocide).

Yugoslav army in battle during Kosovo War, 1998-1999
The International Court of Justice has three sources of jurisdiction through which it can hear a case between states:
  1. if the parties to the case agree through a special agreement to submit their case to the court;
  2. if both parties to the case are also parties to a treaty that requires disputes between member states to be handled by the ICJ; or
  3. if both states have agreed previously to accept the jurisdiction of the court as compulsory in the event that either of the states has a dispute with one another.
    (This is known as compulsory jurisdiction.)

A final point regarding compliance with ICJ decisions is worth noting.

By accepting the UN Charter (i.e. becoming a member of the UN), a state agrees to abide by any decision the ICJ makes in which that country is a party to the case; and if a country is found to be in violation of an ICJ decision, the other party to the case may refer the matter to the Security Council for enforcement.

How useful are international courts for resolving conflicts between states?

Acceptance of Compulsory Jurisdiction of International Court of Justice, August 2, 1946
Chinese Journal of International Law: How “Compulsory” Is It (ICJ)?
International Court of Justice