Picocli JPMS Module

This subproject generates a modular jar picocli-jpms-module-${version}.jar for applications that want to use picocli while taking full advantage of the Java Platform Module System (JPMS) introduced in Java 9.

This jar is generated in addition to the picocli-${version}.jar artifact. Starting from picocli 4.0, picocli-${version}.jar will no longer be an automatic module.

Contents of picocli-jpms-module

• a module-info.class in /META-INF/versions/9/.
• the classes in the picocli package.
• excludes (does not contain) any classes in the picocli.groovy package, so this module has no dependency on Groovy.

Typically, a modular jar includes the module-info.class file in its root directory. This may cause problems for some older tools, which incorrectly process the module descriptor as if it were a normal Java class. To provide the best backward compatibility, the picocli-jpms-module artifact is a modular multi-release jar with the module-info.class file located in META-INF/versions/9.

Using picocli with Java 9 modules

Applications that use Java 9's modules need to configure their module to allow picocli reflective access to the annotated classes and fields.

Often applications want the annotated classes and fields to be private; there should be no need to make them part of the exported API of your module just to allow picocli to access them. The below settings make this possible.

Example module-info.java:

module com.yourorg.yourapp {
    requires info.picocli;

    // Open this package for reflection to external frameworks.
    opens your.package.using.picocli;

    // or: limit access to picocli only
    opens other.package.using.picocli to info.picocli;
}

Note that neither package is exported, so other modules cannot accidentally compile against types in these packages.

Alternatively:

// open all packages in the module to reflective access
open module com.yourorg.yourapp {
    requires info.picocli;
}