SpringBoot Jar cannot load a TrueType Font

Question

I discovered a strange behavior when I want to use a Font, that is included in the springboot fat jar. When running tests on my local machine, which loads a Font from the /resources directory, it works perfectly. But if I build an app with maven and run it from the terminal, then I will receive:

java.io.IOException: Problem reading font data.
at java.awt.Font.createFont0(Font.java:1000)
at java.awt.Font.createFont(Font.java:877)

I tried to find a solution and did the following:

using different Fonts (sometimes with another error about a damaged table or sth.)
built various versions of docker openjdk containers to test behavior
build a ubuntu container, installed openjdk
used a debian image, installed fc-cache and made the Font available via
- /usr/share/fonts/truetype/europlate
- fc-cache -f -v
created a temp-File, just to be sure, that there is no access problem from within the jar.
ran the application from my terminal, where loading the font fails, too
using the font works on Editors, and even when the app runs from the IDE (no test)

The method:

     public Font getFont() throws IOException, FontFormatException {
        File f = File.createTempFile("dang", "tmp");
        assert f != null;
        f.delete();
        ClassLoader classLoader = getClass().getClassLoader();
        Font font = Font.createFont(Font.TRUETYPE_FONT, classLoader.getSystemResourceAsStream("EuroPlate.ttf"));
        font.deriveFont(105f);
        System.out.println(font.getFontName());
        return font;
    }

EDIT: IDE runs application -> works

Terminal runs application -> fails

Stacktrace:

java.io.IOException: Problem reading font data.
    at java.desktop/java.awt.Font.createFont0(Font.java:1183)
    at java.desktop/java.awt.Font.createFont(Font.java:1052)
    at components.NumberPlateUtility.getFont(NumberPlateUtility.java:81)
    at components.NumberPlateUtility.completeImage(NumberPlateUtility.java:173)
    at main.NumberplateClientCommands.one(NumberplateClientCommands.java:63)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:223)
    at org.springframework.shell.Shell.evaluate(Shell.java:169)
    at org.springframework.shell.Shell.run(Shell.java:134)
    at org.springframework.shell.jline.InteractiveShellApplicationRunner.run(InteractiveShellApplicationRunner.java:84)
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:783)
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:773)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1242)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1230)
    at main.Main.main(Main.java:20)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
    at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)

The repository: https://github.com/Semo/numberplate_generator.git

Are you using the same jdk `openjdk` in development environment? — Malathi, Jul 11 '19 at 07:11
@Malathi Well, I tried so many, that I don't know. I will make sure right now and tell the result. RESULT: Same issue, though same versions. — Semo, Jul 11 '19 at 07:19
What are you trying to _do_ with the font? It's extremely uncommon for a Boot application to manipulate a font (as opposed to, for example, serving it to clients to use in the browser). — chrylis -cautiouslyoptimistic-, Jul 11 '19 at 08:12
You meant that you use openjdk x without docker and use the same openjdk x version with docker build. And you get the issue in the dockerised container and not in the environment without docker. Is that right? — Malathi, Jul 11 '19 at 08:13
@chrylis using the font in the backend to render a String into an image and send it to a webservice for further use. — Semo, Jul 11 '19 at 09:43
@Malathi right, excepting that I NOW found out, that the issue occurs in both places containerized/locally, when running the app straight from the terminal without any help from an IDE via `java -jar app.jar`. I pointed that out in my adapted question. — Semo, Jul 11 '19 at 09:48

Malathi · Accepted Answer · 2019-07-11T11:03:04.587

This code will work:

public Font getFont() throws IOException, FontFormatException {
        File f = File.createTempFile("dang", "tmp");
        assert f != null;
        f.delete();
        ClassLoader classLoader = getClass().getClassLoader();
        Font font = Font.createFont(Font.TRUETYPE_FONT, classLoader.getResourceAsStream("EuroPlate.ttf"));
        font.deriveFont(105f);
        System.out.println(font.getFontName());
        return font;
    }

Note the change in classLoader.getResourceAsStream. Check this answer for more explanation.

SpringBoot Jar cannot load a TrueType Font

1 Answers1