how to change custom font to bold italic in java

To change a custom font to bold italic in Java, you can use the deriveFont method of the Font class.

Here's an example of how you might do this:

import java.awt.Font;
import java.io.InputStream;

public class Main {
    public static void main(String[] args) {
        // Load the font from a file
        InputStream stream = Main.class.getResourceAsStream("/fonts/my_font.ttf");
        Font font = Font.createFont(Font.TRUETYPE_FONT, stream).deriveFont(Font.BOLD | Font.ITALIC, 14);

        // Use the font
        // ...
    }
}

In this example, the font is loaded from a file using the createFont method of the Font class. The deriveFont method is then used to create a new font based on the original font, with the Font.BOLD and Font.ITALIC constants used to specify the bold and italic styles. The font size is also specified using the second argument to the deriveFont method.

You can use the deriveFont method to create a font with any combination of styles and sizes as desired.