The following must be run in Processing 3.5.4. Current editor only has JavaFX renderer and not all the requisite libraries apparently.
// Must be run in Processing 3.5.4
import javafx.scene.Scene;
import javafx.stage.Stage;
import javafx.scene.layout.VBox;
import javafx.scene.web.WebView;
void setup() {
size(100, 100, FX2D); // Creates default window in addition to one below.
Stage stage = new Stage();
stage.setTitle("JavaFX WebView Example");
WebView webView = new WebView();
webView.getEngine().load("http://google.com");
VBox vBox = new VBox(webView);
Scene scene = new Scene(vBox, 960, 600);
stage.setScene(scene);
stage.show();
}
void draw() {
}
More info here: https://discourse.processing.org/t/how-to-use-javafx-in-processing-4/35842