The README.md at https://github.com/scijava/scijava-jupyter-kernel mentions Java suppport

Some of the supported languages are Groovy (default), Python, Beanshell, Clojure, Java

However I could not get Java code to work.

I tried Java code by doing:

#!java
String name = "Java"

I get the following error in the terminal
ERROR] Script Language for 'java' not found

If I don't specify a language through the hash syntax the default is Groovy and so the following which is valid Java but invalid Groovy does not work
int[] a = {1}

I get a long stack trace inside Jupyter Notebook
org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'Script1$_run_closure1@e493dee' with class 'Script1$_run_closure1' to class 'int' at org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation.castToNumber(DefaultTypeTransformation.java:163)...