Needs Answer
i use linux devuan.
i installed geogebra with sudo install geogebra , it installs geogebra4,which opened fine.
but i need geogebra5 so i downloaded the .deb file, removed geogebra4 with sudo apt remove and install geogebra5 with sudo dpkg -i.
but geogebra5 does not open well, the menu does not show up:
The same question 
i opened /home/guyuming/.config/geogebra/geogebra.conf , and saw
DEFAULT_JAVACMD='/usr/lib/jvm/java-geogebra/bin/java'
and i can see that the java version is 1.8:
"GeoGebra 5.0.609.0 06 October 2020 Java 1.8.0_121-64bit"
"java -version" command show default java version on my computer is openjdk11.
"which java" command show that its in /usr/bin/java
so i changed default java cmd in /home/guyuming/.config/geogebra/geogebra.conf to what follows:
DEFAULT_JAVACMD='/usr/bin/java'
now, geogebra starts fine and shows:
GeoGebra 5.0.609.0 06 October 2020 Java 11.0.9-64bit
The 3D View might not work well with Java 11.
Please test if this Java 8 works for you: https://www.azul.com/downlo...
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