8311031: JTable header border vertical lines are not aligned with data grid lines

Reviewed-by: abhiscxk, psadhukhan, aivanov

src/java.desktop/share/classes/javax/swing/plaf/metal/MetalBorders.java

@@ -1108,11 +1108,11 @@ public class MetalBorders {
             g.translate( x, y );
 
             g.setColor( MetalLookAndFeel.getControlDarkShadow() );
-            g.drawLine( w-1, 0, w-1, h-1 );
-            g.drawLine( 1, h-1, w-1, h-1 );
+            SwingUtilities2.drawVLine(g, w-1, 0, h-1);
+            SwingUtilities2.drawHLine(g, 1, w-1, h-1);
             g.setColor( MetalLookAndFeel.getControlHighlight() );
-            g.drawLine( 0, 0, w-2, 0 );
-            g.drawLine( 0, 0, 0, h-2 );
+            SwingUtilities2.drawHLine(g, 0, w-2, 0);
+            SwingUtilities2.drawVLine(g, 0, 0, h-2);
 
             g.translate( -x, -y );
         }

test/jdk/javax/swing/JTableHeader/TableHeaderBorderPositionTest.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import javax.imageio.ImageIO;
+import javax.swing.JTable;
+import javax.swing.SwingUtilities;
+import javax.swing.table.JTableHeader;
+import javax.swing.UIManager;
+
+import java.awt.Dimension;
+import java.awt.Graphics2D;
+import java.awt.image.BufferedImage;
+
+import java.io.File;
+import java.io.IOException;
+
+/*
+ * @test
+ * @bug 8311031
+ * @summary Test to validate JTable header border vertical line is
+ *          aligned with data grid lines (Metal L&F).
+ * @run main TableHeaderBorderPositionTest
+ */
+public class TableHeaderBorderPositionTest {
+    private static final double SCALE = 2.25;
+
+    public static void main(String[] args) throws Exception {
+        UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
+        String[][] data = {
+                {"1", "1"}
+        };
+
+        String[] columnNames = {"Size", "Size"};
+
+        JTable table = new JTable(data, columnNames);
+        Dimension tableSize = table.getPreferredSize();
+        table.setSize(tableSize);
+
+        final JTableHeader header = table.getTableHeader();
+        Dimension headerSize = header.getPreferredSize();
+        header.setSize(headerSize);
+
+        Dimension size = new Dimension(Math.max(headerSize.width, tableSize.width),
+                headerSize.height + tableSize.height);
+
+        BufferedImage bufferedImage =
+                new BufferedImage((int)Math.ceil(size.width * SCALE),
+                        (int)Math.ceil(size.height * SCALE),
+                        BufferedImage.TYPE_INT_RGB);
+
+        Graphics2D g2d = bufferedImage.createGraphics();
+        g2d.scale(SCALE, SCALE);
+
+        try {
+            header.paint(g2d);
+            g2d.translate(0, header.getHeight());
+            table.paint(g2d);
+        } finally {
+            g2d.dispose();
+        }
+
+        int verticalLineCol = (int)(table.getTableHeader()
+                                         .getColumnModel()
+                                         .getColumn(0)
+                                         .getWidth() * SCALE) - 2;
+        int expectedRGB = bufferedImage.getRGB(verticalLineCol, 0);
+        int maxHeight = (int)(((double)table.getTableHeader().getHeight() * SCALE)
+                + ((double)table.getRowHeight() * SCALE));
+
+        for (int y = 0; y < maxHeight; y++) {
+            for (int x = verticalLineCol; x < verticalLineCol + 3; x++) {
+                if (expectedRGB != bufferedImage.getRGB(x, y)) {
+                    saveImage(bufferedImage, "failureImage.png");
+                    throw new RuntimeException("Test Failed at <" + x + ", " + y + ">");
+                }
+            }
+        }
+        System.out.println("Test Passed");
+    }
+
+    private static void saveImage(BufferedImage image, String fileName) {
+        try {
+            ImageIO.write(image, "png", new File(fileName));
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}