Program: 80035
Project: 80035
Buggy source:
/** 
 * Sets the paint used to draw or fill shapes (or text).  If   {@code paint} is an instance of {@code Color}, this method will also update the current color attribute (see   {@link #getColor()}). If  you pass   {@code null} to this method, it does nothing (in accordance with the JDK specification). <br><br> Note that this implementation will map  {@link Color},   {@link GradientPaint},   {@link LinearGradientPaint} and {@link RadialGradientPaint} to JavaFX equivalents, other paint implementations are not handled.
 * @param paint  the paint ({@code null} is permitted but ignored).
 * @see #getPaint() 
 */
@Override public void setPaint(Paint paint){
  if (paint == null) {
    return;
  }
  if (paintsAreEqual(paint,this.paint)) {
    return;
  }
  this.paint=paint;
  if (paint instanceof Color) {
    setColor((Color)paint);
  }
 else   if (paint instanceof GradientPaint) {
    GradientPaint gp=(GradientPaint)paint;
    Stop[] stops=new Stop[]{new Stop(0,awtColorToJavaFX(gp.getColor1())),new Stop(1,awtColorToJavaFX(gp.getColor2()))};
    Point2D p1=gp.getPoint1();
    Point2D p2=gp.getPoint2();
    LinearGradient lg=new LinearGradient(p1.getX(),p1.getY(),p2.getX(),p2.getY(),false,CycleMethod.NO_CYCLE,stops);
    this.gc.setStroke(lg);
    this.gc.setFill(lg);
  }
 else   if (paint instanceof MultipleGradientPaint) {
    MultipleGradientPaint mgp=(MultipleGradientPaint)paint;
    Color[] colors=mgp.getColors();
    float[] fractions=mgp.getFractions();
    Stop[] stops=new Stop[colors.length];
    for (int i=0; i < colors.length; i++) {
      stops[i]=new Stop(fractions[i],awtColorToJavaFX(colors[i]));
    }
    if (paint instanceof RadialGradientPaint) {
      RadialGradientPaint rgp=(RadialGradientPaint)paint;
      Point2D center=rgp.getCenterPoint();
      Point2D focus=rgp.getFocusPoint();
      double focusDistance=focus.distance(center);
      double focusAngle=0.0;
      if (!focus.equals(center)) {
        focusAngle=Math.atan2(focus.getY() - center.getY(),focus.getX() - center.getX());
      }
      double radius=rgp.getRadius();
      RadialGradient rg=new RadialGradient(Math.toDegrees(focusAngle),focusDistance,center.getX(),center.getY(),radius,false,CycleMethod.NO_CYCLE,stops);
      this.gc.setStroke(rg);
      this.gc.setFill(rg);
    }
 else     if (paint instanceof LinearGradientPaint) {
      LinearGradientPaint lgp=(LinearGradientPaint)paint;
      Point2D start=lgp.getStartPoint();
      Point2D end=lgp.getEndPoint();
      LinearGradient lg=new LinearGradient(start.getX(),start.getY(),end.getX(),end.getY(),false,CycleMethod.NO_CYCLE,stops);
      this.gc.setStroke(lg);
      this.gc.setFill(lg);
    }
  }
 else {
  }
}

Fixed version (ground truth):
/** 
 * Sets the paint used to draw or fill shapes (or text).  If   {@code paint} is an instance of {@code Color}, this method will also update the current color attribute (see   {@link #getColor()}). If  you pass   {@code null} to this method, it does nothing (in accordance with the JDK specification). <br><br> Note that this implementation will map  {@link Color},   {@link GradientPaint},   {@link LinearGradientPaint} and {@link RadialGradientPaint} to JavaFX equivalents, other paint implementations are not handled.
 * @param paint  the paint ({@code null} is permitted but ignored).
 * @see #getPaint() 
 */
@Override public void setPaint(Paint paint){
  if (paint == null) {
    return;
  }
  if (paintsAreEqual(paint,this.paint)) {
    return;
  }
  applyPaint(paint);
}