FULL PRODUCT VERSION :
openjdk version "14-ea" 2020-03-17
OpenJDK Runtime Environment (build 14-ea+23-1048)
OpenJDK 64-Bit Server VM (build 14-ea+23-1048, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Mac OS X

A DESCRIPTION OF THE PROBLEM :
With Japanese Mac OS X, Japanese characters with Serif font
are displayed too upper position. A few dots are over JTextField's area.

"Hiragino Mincho ProN W3" seems to be used.

Other logical fonts don't have the problem.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile and launch the sample code with Japanese fonts

EXPECTED VERSUS ACTUAL BEHAVIOR :
Expected:
All glyphs can be fit in the JTextField area.
Actual:
A few dots of top of Japanese characters are out of the JTextField area.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.Font;
import javax.swing.*;

public class JTFieldTest {
    public static void main(String[] args) {
        JFrame f = new JFrame();
        JTextField t = new JTextField("TTT\u4e9c\u5516\u5a03\u963f\u54c0\u611b\u6328\u59f6\u9022\u8475\u831c\u7a50");
        t.setFont(new Font(Font.SERIF, Font.PLAIN, 29));
        f.add(t);
        f.pack();
        f.setVisible(true);
    }
}
---------- END SOURCE ----------