When I look at https://github.com/JanusGraph/janusgraph/blob/ce79ec50e0c882c9ccc62e73a2054bcdb2304ece/janusgraph-dist/src/assembly/static/bin/gremlin.bat#L119

I see use of the deprecated http://tinkerpop.apache.org/javadocs/3.2.10/full/org/apache/tinkerpop/gremlin/groovy/jsr223/ScriptExecutor.html
By  http://tinkerpop.apache.org/javadocs/3.4.10/full/org/apache/tinkerpop/gremlin/groovy/jsr223 the class has been removed.

It seems the fix is to replace
java %JAVA_OPTIONS% %JAVA_ARGS% -cp %CP% org.apache.tinkerpop.gremlin.groovy.jsr223.ScriptExecutor %strg%
...with... java %JAVA_OPTIONS% %JAVA_ARGS% -cp "%LIBDIR%*;%EXTDIR%;" org.apache.tinkerpop.gremlin.console.Console %*

Should an issue be opened to fix this?