Nexss Programmer don't need Java to run. Please check the LICENSE at java.com https://java.com/en/download/faq/distribution.xml
To Install Nexss Programmer please go to Nexss Programmer CLI for more information.
nexss java default compiler java8 # Version 8
nexss java default compiler java13 # Version 13
Nexss Programmer 2.0 has CLASSPATH specified to the current folder lib/ .If you would like to include some jar files please make lib folder in your project and put your external libraries there. For example, nexss programmer uses json-20190722.jar file which allow to parse and make json format and file is copied during adding HelloWorld.java and Default.java Nexss Programmer templates.
What is CLASSPATH 5 ways to add multiple JAR in to Classpath in Java
java -version # check jre version
javac -version # check which compiler
java -XshowSettings:properties -version
https://www.baeldung.com/java-org-json
https://www.geeksforgeeks.org/parse-json-java/
https://www.edureka.co/blog/cheatsheets/java-cheat-sheet/