Send data from java to JavaScript using WebView

i’m trying to make a map java project using web view , i want to send the Longitude and Latitude from java to JavaScript .

i have used the webengine.executeScript("latitude") like this

Java

private Double longitude = 48.8588336;
private Double latitude = 2.2769956;
/*code*/
latitude= (Double) webengine.executeScript("latitude");

JavaSript

let longitude;
  let latitude;
  var map = L.map('map').setView([longitude,latitude], 13);

the Longitude and latitude didn’t send to Js.