button doesn't change colour after scene building in JavaFX - javafx

Question

I would like to change the colour of a button after I build the scene.
I have to do a battleship. When I place a boat many buttons have to change their colours.
So, I have a function do to it and I test that. I filter the boxes contained in "oceanBoxes" by their coordinates and when I get true I call function putBoatInside.
private void placeGuiBoat(int x, int y, int direction, int size) {
List<Integer> listBoxesBoatNeed;
if(direction == HORIZONTAL) {
listBoxesBoatNeed = IntStream.range(y,y+size).boxed().collect(Collectors.toList());
try {
listBoxesBoatNeed.forEach(e -> oceanBoxes.stream().filter(p->p.getX() == x && p.getY() == e).findFirst().orElse(null).putBoatInside());
} catch(Exception e) {}
}
}
And in Boxe class, I have this
public void putBoatInside() {
this.setStyle("-fx-background-color:#000;");
}
EDIT
Here the minimal reproducible example I made to solve it and see that the problem wasn't there.
Main
package application;
import javafx.scene.layout.GridPane;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import GUI.BtnOcean;
import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.Button;
public class Main extends Application {
#Override
public void start(Stage primaryStage) {
try {
GridPane root = new GridPane();
BtnOcean btn = new BtnOcean(1,1);
BtnOcean btn1 = new BtnOcean(1,2);
BtnOcean btn2 = new BtnOcean(1,3);
BtnOcean btn3 = new BtnOcean(1,4);
BtnOcean btn4 = new BtnOcean(1,5);
ArrayList<BtnOcean> ocean = new ArrayList<BtnOcean>(Arrays.asList(btn,btn1,btn2,btn3,btn4));
Button btn5 = new Button("change");
List<Integer> list = IntStream.range(1,5).boxed().collect(Collectors.toList());
btn5.setOnAction(j -> {
list.stream().forEach(e -> ocean.stream().filter( p-> p.getX() == 1 && p.getY() == e ).findFirst().orElse(null).putBoatInside());
});
root.add(btn, 0, 0);
root.add(btn1, 1, 0);
root.add(btn2, 2, 0);
root.add(btn3, 3, 0);
root.add(btn4, 4, 0);
root.add(btn5, 5, 0);
Scene scene = new Scene(root,1200,800);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();
} catch(Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
launch(args);
}
}
BtnOcean class
package GUI;
import javax.swing.ImageIcon;
import javafx.scene.control.Button;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
public class BtnOcean extends Button{
private int x;
private int y;
private String cssProps = "-fx-background-color:#fff;" +
"-fx-border-color:#000000;"+
"-fx-border-width: 1px;";
public BtnOcean(int x, int y,String text){
this.x = x;
this.y = y;
setMinHeight(60);
setMinWidth(60);
setStyle(cssProps);
setText(text);
}
public BtnOcean(int x, int y){
this.x = x;
this.y = y;
setMinHeight(60);
setMinWidth(60);
setStyle(cssProps);
}
public void putBoatInside() {
System.out.println(this);
this.setStyle("-fx-background-color:#000;");
}