How do I install some default fonts to Openjdk 8 running in Docker

Question

I have a Docker file Java based application - https://hub.docker.com/r/songkong/songkong/~/dockerfile/

One problem is that the DockerFile does not seem to come with any fonts installed and this causes this error for my application

java.lang.NullPointerException
    at sun.awt.FontConfiguration.getVersion(FontConfiguration.java:1264)
    at sun.awt.FontConfiguration.readFontConfigFile(FontConfiguration.java:219)
    at sun.awt.FontConfiguration.init(FontConfiguration.java:107)
    at sun.awt.X11FontManager.createFontConfiguration(X11FontManager.java:774)
    at sun.font.SunFontManager$2.run(SunFontManager.java:431)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.font.SunFontManager.<init>(SunFontManager.java:376)
    at sun.awt.FcFontManager.<init>(FcFontManager.java:35)
    at sun.awt.X11FontManager.<init>(X11FontManager.java:57)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.Class.newInstance(Class.java:442)
    at sun.font.FontManagerFactory$1.run(FontManagerFactory.java:83)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.font.FontManagerFactory.getInstance(FontManagerFactory.java:74)
    at java.awt.Font.getFont2D(Font.java:491)
    at java.awt.Font.canDisplayUpTo(Font.java:2060)
    at java.awt.font.TextLayout.singleFont(TextLayout.java:470)
    at java.awt.font.TextLayout.<init>(TextLayout.java:531)
    at org.apache.poi.ss.util.SheetUtil.getDefaultCharWidth(SheetUtil.java:275)
    at org.apache.poi.xssf.streaming.AutoSizeColumnTracker.<init>(AutoSizeColumnTracker.java:117)
    at org.apache.poi.xssf.streaming.SXSSFSheet.<init>(SXSSFSheet.java:79)
    at org.apache.poi.xssf.streaming.SXSSFWorkbook.createAndRegisterSXSSFSheet(SXSSFWorkbook.java:656)
    at org.apache.poi.xssf.streaming.SXSSFWorkbook.createSheet(SXSSFWorkbook.java:677)
    at org.apache.poi.xssf.streaming.SXSSFWorkbook.createSheet(SXSSFWorkbook.java:83)
    at com.jthink.songkong.reports.spreadsheet.Worksheet.<init>(Worksheet.java:23)
    at com.jthink.songkong.reports.spreadsheet.BasicWorksheet.<init>(BasicWorksheet.java:15)
    at com.jthink.songkong.reports.spreadsheet.SpreadsheetReport.<init>(SpreadsheetReport.java:51)
    at com.jthink.songkong.reports.fixsongsreport.SpreadsheetReportSection.outputReport(SpreadsheetReportSection.java:82)
    at com.jthink.songkong.reports.FixSongsReport.outputSpreadsheet(FixSongsReport.java:1033)
    at com.jthink.songkong.reports.FixSongsReportCreator.createReport(FixSongsReportCreator.java:122)
    at com.jthink.songkong.analyse.toplevelanalyzer.FixSongsController.start(FixSongsController.java:329)
    at com.jthink.songkong.server.callback.ServerFixSongs$Task.run(ServerFixSongs.java:448)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

I have had this issue before on a (non Docker) linux installation, and I got round it by adding some fonts to my application download and then using

fc-cache -rv /opt/songkong/fonts

to install the fonts

So I added the fonts to the application download and then added

CMD fc-cache -rv /opt/songkong/fonts;

to my DockerFile but it hasn't worked

Probably this is not the correct way to do this, is there a correct way.

Answer 1

Answer derived from https://unix.stackexchange.com/questions/438257/how-to-install-microsoft-true-type-font-on-alpine-linux

I found that fp-cache does not exist as part of the openjdk:8-jre-alpine distribution

But adding:

RUN apk --no-cache add msttcorefonts-installer fontconfig && \
    update-ms-fonts && \
    fc-cache -f

to my Dockerfile not only added fc-cache, but also installed a default set of fonts.

This is all that was needed to resolve the Java problem (I could also remove the fc-cache -rv /opt/songkong/fonts line) and allowed me to create Excel spreadsheets with the jakarta-poi library.