Install librelaxng-datatype-java by entering the following commands in the terminal:
sudo apt update sudo apt install librelaxng-datatype-java
Description:
Java datatype interface for RELAX NG
RELAX NG is a schema language for XML. This library is a Java interface for describing datatypes within RELAX NG.
Homepage: http://sourceforge.net/projects/relaxng/
Version: 1.0+ds1-3
Section: universe/java