question: public Plot add ( String label , Population population , int x , int y ) { List < Number > xs = new ArrayList < Number > ( ) ; List < Number > ys = new ArrayList < Number > ( ) ; for ( Solution solution : population ) { if ( ! solution . violatesConstraints ( ) ) { xs . add ( solution . getObjective ( x ) ) ; ys . add ( solution . getObjective ( y ) ) ; } } scatter ( label , xs , ys ) ; setLabelsIfBlank ( "Objective " + ( x + 1 ) , "Objective " + ( y + 1 ) ) ; return this ; }
target:  Displays the solutions in the given population in a 2D scatter plot. The two given objectives will be displayed.