`exportgraphics` to PDF causes Java error in Arch/Manjaro Linux

Hello everyone,

When I try to export the figure to PDF vector graphics, the exportgrachics function fails with Java error and generates a empty PDF.

A minimal example could be:

ezplot('sin(x)')
exportgraphics(gcf,'sin.pdf')

and the corresponding Java error is:

Error using exportgraphics

java.lang.NullPointerException
	at org.apache.fop.fonts.autodetect.FontInfoFinder.find(FontInfoFinder.java:219)
	at org.apache.fop.fonts.FontAdder.add(FontAdder.java:63)
	at org.apache.fop.fonts.FontDetectorFactory$DefaultFontDetector.detect(FontDetectorFactory.java:105)
	at org.apache.fop.fonts.FontManager.autoDetectFonts(FontManager.java:229)
	at org.apache.fop.fonts.DefaultFontConfigurator.configure(DefaultFontConfigurator.java:82)
	at
    org.apache.fop.svg.PDFDocumentGraphics2DConfigurator.createFontInfo(PDFDocumentGraphics2DConfigurator.java:143)
    	at
    org.apache.fop.svg.PDFDocumentGraphics2DConfigurator.configure(PDFDocumentGraphics2DConfigurator.java:87)
    	at com.mathworks.hg.print.FOPFontConfigurator.configurePDFFonts(FOPFontConfigurator.java:57)
	at com.mathworks.hg.print.FOPPDFVectorStrategy.startJob(FOPPDFVectorStrategy.java:89)
	at com.mathworks.hg.util.HGVectorOutputHelper.open(HGVectorOutputHelper.java:74) 
    

The same problem occurs in my both Arch and Manjaro system, the system infomations are below:

• MATLAB version: R2022a
• Linux kernel: Arch 5.18, Manjaro 5.15
• System default Java: java18-openjdk

The function worked very well in MATLAB R2021b before, but I have uninstalled the previous version.

Since Arch/Manjaro is not officially support by MathWorks, I have to turn to the community for help. I would appreciate if anyone could give me some solutions or suggestions. Thanks for your attention.

[Tri Nguyen]

I got this issue too, after I ran pacman update. Looking forword to some solution.

Answer 1

[Abhishek Chakram]

Hi Chunyu Xiao,

It is my understanding that you have encountered a Java error when using the exportgraphics function to export a figure to PDF in MATLAB on Arch/Manjaro Linux, it could be due to a compatibility issue with the Java Runtime Environment (JRE) on your system.

Here are a few steps you can try to resolve the issue:

1. Update your Java installation: Make sure you have the latest version of Java installed on your system. You can update Java by running the following command in the terminal:

 sudo pacman -Syu jre-openjdk

This command will update the JRE to the latest version available in the Arch Linux repositories.

2. Set the Java version for MATLAB: MATLAB might be using a different Java version than the one installed on your system. To ensure MATLAB uses the updated Java version, you can try setting the MATLAB_JAVA environment variable to the path of the JRE installation. Open a terminal and run the following command:

export MATLAB_JAVA=/usr/lib/jvm/java-<version>-openjdk

Replace <version> with the appropriate version number of the JRE installed on your system.

3. Use an alternative method to export to PDF: If the above steps do not resolve the issue, you can try using an alternative method to export the figure to PDF. For example, you can use the print [AJ1] function with the -dpdf option to save the figure as a PDF file:

print('figure_name.pdf', '-dpdf')

Replace 'figure_name.pdf' with the desired file name and path.

Best Regards,

Abhishek Chakram