Starting JavaFX application several times results in multiple instances of application running. Sometimes it is required that only a single instance of an application should run.

Provide feature so that attempting to start a second copy should typically result in the second copy detecting that the first copy is running, and then sending a message to the first copy asking it to display a new window or raise its current window.

Other UI toolkits already provide built-in support for this:

Qt : QtSingleApplication
GTK : GtkApplication

SceneBuilder already supports something like this.