Change edge color in JMenu?

Question

Java

I created a JMenuBar and JMenu in it, added all the necessary styles, but bad luck - the top and bottom gaps are white:


How to remove this?

Answer 1

"look and fill " is responsible for the borders
https://docs.oracle.com/javase/tutorial/uiswing/lo...
https://progi.pro/swing-lf-import-i-realizaciya-6...

Answer 2

Try calling this method:

/**
     * Sets the current system look and feel properties
     */
    public static void setSystemLookAndFeel() {
        /* Get the default operation system style */
        final String uiName = UIManager.getSystemLookAndFeelClassName();
        /* Set this default current style for our task */
        try {
            UIManager.setLookAndFeel( uiName );
        } catch ( Exception ex ) {
            System.err.printf( "--- Can't set GUI default system style (%s):%s%n", uiName, ex.getMessage() );
        }
    }

Somewhere at the beginning of the JFrame constructor of the program's main window.
Maybe the problem will disappear and everything will be fine.