Hiragana/Katakana characters are not rendered equaly spaced out using getJustifiedLayout()

When We ran the testcase src/GS/font-render/2d/two/TextLayoutTest.java on Rehdhat_amd64-
5.ja_JP.UTF-8 config. Words are not be rendered equaly spaced out on line 3. The JAVA_HOME
is 5u15b01,the GlobalSuite is gs15UR-b03.tar. TextLayoutTest-Line3.JPG is the screen shot
in attachements. This issue is produced in Windows/Linux/Solaris for 5u15b01 and 6u5b10.

This issue can be produced using TextLayoutTest.java in in attachements.TextLayouTest.png is the screen shot of TextLayoutTest.java in attachements.
The issue is produced That We ran TextLayoutTest.java program on JDK1.6.0_03-b05.
Below is the source code of TextLayoutTest.java:

-------------------- Source Begin -----------------------------
/**
 * @author Zhaoxiong.zhang
 */
import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;

public class TextLayoutTest extends Frame {
     public static void main(String[] args) {
        TextLayoutTest frame=new TextLayoutTest();
        frame.setTitle("Text Layou Test");
    }
    
    public TextLayoutTest() {

        _TextLayoutTest test = new _TextLayoutTest();
        add("Center", test);
        setSize(400, 200);
        setVisible(true);
        addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent e){
                System.exit(0);
            }
        });
    }

    class _TextLayoutTest extends Canvas {
        private TextLayout tl1,tl2,copytl1,copytl2;
        private Font smallFont;
        private String ftName;
        //Any CJK Unified caracter, unicode range is 4E00-9FBF. Words are be rendered equaly
spaced out.
        String str1 = "\u8fd9\u679a\u91d1\u724c\u5c06\u4e0d\u662f\u5f52\u4e8e\u662f";
        // Any hiragana(3040-309F) or katagana(30A0-30F) character. Words are not be
rendered equaly spaced out
        String str2 = "\u3042\u3044\u3046\u3048\u304a\u30ac\u30ae\u30b0\u30b2\u30b4";
        
        public _TextLayoutTest() {
            ftName = "Dialog";
            smallFont = new Font(ftName, Font.ITALIC, 24);
            tl1 = new TextLayout(str1, smallFont,new FontRenderContext(null, false, false));
            tl2 = new TextLayout(str2, smallFont,new FontRenderContext(null, false, false));
        }

        public void paint(Graphics g) {
            Graphics2D g2d = (Graphics2D)g;
            int w = getSize().width;

            // getJustifiedLayout()
            TextLayout copytl1 = tl1.getJustifiedLayout(w);
            TextLayout copytl2 = tl2.getJustifiedLayout(w);
            copytl1.draw(g2d, 0.0f, 40);
            copytl2.draw(g2d, 0.0f, 100);
        }
    }
}

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