The header border uses `g.drawLine` whereas the JTable data grid lines uses `SwingUtilities2.drawVLine` and `SwingUtilities2.drawHLine` to draw horizontal and vertical lines. The SwingUtilities2 uses `Graphics.fillRect` which contributes to the difference between the position of these two lines which happens/visible at higher ui scaling (difference in alignment between vertical lines of these two). The fix propose to use the same methods for metal L&F of JTable header border paint. CI testing shows green.
------------- Commit messages: - Remove white space from test - Fix + Manual Test Changes: https://git.openjdk.org/jdk/pull/14766/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14766&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8311031 Stats: 93 lines in 2 files changed: 89 ins; 0 del; 4 mod Patch: https://git.openjdk.org/jdk/pull/14766.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/14766/head:pull/14766 PR: https://git.openjdk.org/jdk/pull/14766
