alpine asciidoctor ditaa

asciidoctor: FAILED: /documents/test.adoc: Failed to parse source, Ditaa image generation failed: java.lang.NullPointerException
	at sun.awt.X11FontManager.getDefaultPlatformFont(X11FontManager.java:779)
	at sun.font.SunFontManager$2.run(SunFontManager.java:433)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.font.SunFontManager.<init>(SunFontManager.java:376)
	at sun.awt.X11FontManager.<init>(X11FontManager.java:32)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at java.lang.Class.newInstance(Class.java:379)
	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 sun.font.SunFontManager.getInstance(SunFontManager.java:250)
	at sun.font.FontDesignMetrics.getMetrics(FontDesignMetrics.java:264)
	at sun.java2d.SunGraphics2D.getFontMetrics(SunGraphics2D.java:819)
	at org.stathissideris.ascii2image.graphics.FontMeasurer.getAscent(Unknown Source)
	at org.stathissideris.ascii2image.graphics.FontMeasurer.getFontFor(Unknown Source)
	at org.stathissideris.ascii2image.graphics.FontMeasurer.getFontFor(Unknown Source)
	at org.stathissideris.ascii2image.graphics.Diagram.<init>(Unknown Source)
	at org.stathissideris.ascii2image.core.CommandLineConverter.doConvert(Unknown Source)
	at org.stathissideris.ascii2image.core.CommandLineConverter.convert(Unknown Source)
 (RuntimeError)