This issue most likely occurs because Java does not recognize the text font, and is unable to render the correct format, as if the text font is missing altogether.
To resolve this issue:
1. Add "fallback" directory under (matlabroot)/sys/java/jre/glnxa64/jre/lib/fonts
2. Add a link for a Japanese font of your choice with the following commands:
ln -s /usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc NotoSansCJK-Regular.ttc
Then "ls" command displays below:
NotoSansCJK-Regular.ttc -> /usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc
3. Close and relaunch MATLAB