FULL PRODUCT VERSION :
java version "1.8.0_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Yosemite 10.10.5

EXTRA RELEVANT SYSTEM CONFIGURATION :
MacBook Pro 13", Retina, with external, non-Retina screen attached via DisplayPort.

A DESCRIPTION OF THE PROBLEM :
Font rendering looks wrong when certain characters are adjacent, it looks acceptable on the Retina screen, but less so on the non-Retina screen. I have screenshots demonstrating the issue.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Standard system font on JavaFX button, with characters 'r' and 't' adjacent, i.e. I have a button with:

'Let's get started...' where the r and t in 'started' looks wrong.

Making a new FXML project in NetBeans, and putting 'Let's get started...' into the button will demonstrate the issue.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I would expect the text to be kerned correctly on both screens.
ACTUAL -
On the Retina screen, the text appears acceptable kerned (not sure if it's 100% correct), but on the non-Retina, it's notably different.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package kernfx;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

/**
 *
 * @author gt
 */
public class KernFX extends Application {
    
    @Override
    public void start(Stage stage) throws Exception {
        Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
        
        Scene scene = new Scene(root);
        
        stage.setScene(scene);
        stage.show();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }
    
}




/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package kernfx;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;

/**
 *
 * @author gt
 */
public class FXMLDocumentController implements Initializable {
    
    @FXML
    private Label label;
    
    
    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }
    
}





<?xml version="1.0" encoding="UTF-8"?>

<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<AnchorPane id="AnchorPane" prefHeight="200" prefWidth="320" xmlns:fx="http://javafx.com/fxml/1" fx:controller="kernfx.FXMLDocumentController">
    <children>
        <Button layoutX="126" layoutY="90" text="Let's get started..." />

    </children>
</AnchorPane>

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
No workaround, other than to use a Retina screen.