Prerequisites for Font Support in AdoptOpenJDK

January 22, 2021 – posted by   Andreas Ahlenstorf

Back in the day when everybody got their JDK from Sun and later Oracle it included an assortment of fonts that could be used in addition to the fonts installed on the host. OpenJDK has not bundled any fonts for years (if it ever has), and Oracle did away with the bundled fonts starting with Oracle JDK 11. Already with OpenJDK 9 font configuration files were removed except on Windows.

This has a couple of implications for OpenJDK distributions, including AdoptOpenJDK: Your system might need additional packages and configuration beyond the AdoptOpenJDK installation for proper font support, especially on Linux.

macOS, and Windows

Font integration should work out of the box, no matter whether you are using binary builds (compressed tarballs, ZIP archives) or operating system packages (if available).

Linux

On Linux, you need Freetype and Fontconfig to enable OpenJDK to discover and use fonts. If you have neither, you might stumble upon unhelpful exceptions like:

Caused by: java.lang.NullPointerException
    at java.desktop/sun.awt.FontConfiguration.getVersion(FontConfiguration.java:1288)
    at java.desktop/sun.awt.FontConfiguration.readFontConfigFile(FontConfiguration.java:225)
    at java.desktop/sun.awt.FontConfiguration.init(FontConfiguration.java:107)
    at java.desktop/sun.awt.X11FontManager.createFontConfiguration(X11FontManager.java:765)
    at java.desktop/sun.font.SunFontManager$2.run(SunFontManager.java:440)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at java.desktop/sun.font.SunFontManager.<init>(SunFontManager.java:385)
    at java.desktop/sun.awt.FcFontManager.<init>(FcFontManager.java:35)
    at java.desktop/sun.awt.X11FontManager.<init>(X11FontManager.java:56)
    ... 36 more

In addition to that, you need some fonts. DejaVu is a family of free fonts based on Vera and included in most (if not all) Linux distributions. This makes it a solid choice. The following commands should install all the necessary packages:

• Debian/Ubuntu/Mint: apt-get install libfreetype6 fontconfig fonts-dejavu
• RHEL/CentOS/Fedora: yum install freetype fontconfig dejavu-sans-fonts
• SLES/OpenSUSE: zypper install libfreetype6 fontconfig dejavu-fonts

If you have a desktop environment installed on your system, those packages should already be present, and there is nothing left to do. If you have installed AdoptOpenJDK using our operating system packages (rpm, deb), all necessary packages will automatically be installed starting with 8u282, 11.0.10, and 15.0.2 released in January 2021.

AIX

On AIX, the situation is similar to Linux. You need Freetype, Fontconfig, and fonts. On the systems available to us, everything came with the operating system and as such, Java could use the fonts out of the box.

Solaris

On Solaris, you need Freetype, Fontconfig, and fonts, too. You should be able to install those using:

pkg install system/library/freetype-2
pkg install font/truetype/dejavu

If you have a desktop environment installed, all the necessary libraries should already be present.

Checking the Font Support

If you want to test whether the font support works on your system, here is a small sample program that should output the name of fonts installed on your system if everything is alright:

import java.awt.*;

public class FontTest {

    public static void main(String[] args) {
        String[] names = GraphicsEnvironment.getLocalGraphicsEnvironment().getAvailableFontFamilyNames();

        System.out.println("Found " + names.length + " fonts:");

        for (String name : names) {
            System.out.println(name);
        }
    }
}

That’s the output on a Fedora 33 system without desktop environment that was configured according to the instructions given above:

Found 8 fonts:
DejaVu Sans
DejaVu Sans Condensed
DejaVu Sans Light
Dialog
DialogInput
Monospaced
SansSerif
Serif

The list of fonts varies depending on the operating system and its configuration.

Do you have questions or want to discuss this post? Hit us up on the AdoptOpenJDK Slack workspace!