A DESCRIPTION OF THE PROBLEM :
The linebreaker.nextLayout() method is 10 times slower since the first JDK9 update.
I need it to draw multiline text in a canvas or to evaluate the height of a multi-line text in a grid cell.
I did a very simple test case which reproduce it always. The "textLayout.draw(g, 0, y);" is not necessary to reproduce the problem.

REGRESSION : Last worked in version 8u172

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Execute the following program with JDK8 and JDK 10

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
It takes 1341ms with JDK8
ACTUAL -
It takes 15731ms with JDK10
It takes more than 15s too with the JDK11-ea+10 too.

---------- BEGIN SOURCE ----------
package Tests;



import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.font.LineBreakMeasurer;
import java.awt.font.TextLayout;
import java.text.AttributedString;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main extends JPanel {

  public void paint(Graphics g) {
    Graphics2D g2d = (Graphics2D) g;
    long lTime = System.currentTimeMillis();
    int y = 0;
    for (int i = 0 ; i < 10000; i++) {
      y = drawParagraph(g2d, "adfasdfaf", 20, y);
    }
    System.out.println(System.currentTimeMillis() - lTime + " Milli-seconds");
  }

  int drawParagraph(Graphics2D g, String paragraph, float width, int yPosition) {
    LineBreakMeasurer linebreaker = new LineBreakMeasurer(new AttributedString(paragraph)
        .getIterator(), g.getFontRenderContext());

    int y = yPosition;
    while (linebreaker.getPosition() < paragraph.length()) {
      TextLayout textLayout = linebreaker.nextLayout(width);
      // Unecessary part of the test
      y += textLayout.getAscent();
      textLayout.draw(g, 0, y);
      y += textLayout.getDescent() + textLayout.getLeading();
    }
    return y;
  }

  public static void main(String[] args) {

    JFrame frame = new JFrame("Basic Shapes");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(new Main());
    frame.setSize(350, 250);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}
---------- END SOURCE ----------

FREQUENCY : always