I was trying to use joptsimple package in my project but I get following error:
Error:(4, 20) java: package jdk.internal.joptsimple is not visible
(package jdk.internal.joptsimple is declared in module jdk.internal.opt, which does not export it to the unnamed module)
Any ideas what should I do with it?
Well, the message clearly reads (in fact notice the beautiful naming convention by JDK devs "internal" meaning they don't want to expose them) that the API you're trying to access is in a package that is not exported to any other module except these -
exports jdk.internal.joptsimple to jdk.jlink, jdk.jshell
even if you add requires jdk.internal.opt module in your declaration.
To make use of classes from these packages should be avoided.
Also since even the Open JDK itself integrates JOpt Simple for internal usage by JDK tools. I would suggest you make use of the library jopt-simple for a long-term solution by adding the dependency on your modulepath(java9) or classpath(java8) using -
Maven -
<dependency>
<groupId>net.sf.jopt-simple</groupId>
<artifactId>jopt-simple</artifactId>
<version>6.0-alpha-2</version>
</dependency>
Gradle:-
compile 'net.sf.jopt-simple:jopt-simple:6.0-alpha-2'
After the inclusion of which the package name in use in your classes shall simply be joptsimple.* instead of jdk.internal.joptsimple.*