A more thorough explanation:

Uti possidetis juris (UPJ) is a principle of customary international law that helps to maintain the boundaries of colonies that become independent states. This principle was first used to establish the borders of newly independent territories in Latin America, but it is now used in other parts of the world, especially in Africa.

The purpose of UPJ is to prevent conflicts over borders that could threaten the stability of new states. When a colony becomes independent, UPJ ensures that the borders established by the former colonial power are respected. This helps to prevent disputes over land and resources that could lead to violence.

For example, when Spain gave up control of its colonies in Latin America, UPJ was used to establish the borders of the new states. This prevented other countries from trying to claim land that had been assigned to one of the new states.

Another example is the case of Burkina Faso and Mali. In 1986, the International Court of Justice used UPJ to settle a dispute over their border. The court ruled that the border should be based on the borders that had been established by the former colonial power, France.

Overall, UPJ is an important principle that helps to maintain peace and stability in newly independent states. By respecting the borders established by the former colonial power, UPJ helps to prevent conflicts over land and resources.