JDK Compatibility

Source

Historically our source code was Java 7 compliant. However, as of 3.0.0 we moved to Java 11 as the minimum supported JDK version so expect our codebase to adopt more modern Java syntax as it continues to evolve.

Build

Airline can be built with Java 11 or higher. Regardless of the version built the pom.xml will target Java 11 byte code.

Airline may not build with very recent JDKs if there are any incompatibilities with our choice of Maven plugins and/or dependencies. Please report these issues via our GitHub so we can address them.

Runtime

Airline is built with Java 11 so can be used with Java 11 or above.

JPMS

This feature requires a minimum version of 2.7.0

Airline does make heavy use of reflection and therefore will likely not work on the Module Path without exporting packages that contain your CLI and Command classes as part of your module-info.java. For example:

module com.yourdomain.yourmodule
{
    requires com.github.rvesse.airline;
    
    exports com.yourdomain.yourpackage;
    
    // As Airline is driven by reflection over the annotations on your classes you need 
    // to open packages containing Airline annotated types to the com.github.rvesse.airline module
    opens com.yourdomain.yourpackage to com.github.rvesse.airline;
}

This feature requires a minimum version of 3.0.0

Prior to 3.0.0 Airline only provided basic module-info.java files, as of 3.0.0 these have been properly authored to provide full JPMS compatibility.

If you are using any of the Airline annotations that locate resources e.g. @Version then your resources MUST satisfy the following constraints to continue to be usable:

• They should be placed in a package that matches your modules name e.g. if your module is com.yourdomain.app then your resources should be in that package
• The package containing the resources needs to be unconditionally open

If these constraints are met then the new ModulePathLocator introduced in 3.0.0 should allow locating such resources.

If you cannot meet these constraints then your resources will no longer be usable if you run your application on the Module Path. If this is the case you can add the airline-jpms-resources module as an additional dependency and reference the JpmsResourceLocator.class in the relevant field of your annotations e.g. sourceLocators for the @Version annotation, this uses the ClassGraph to locate resources at the cost of breaking the strong encapsulation that modules are intended to provide.

If you encounter a problem with this please report it at https://github.com/rvesse/airline/issues.

Improving this Documentation

This documentation is itself open source and lives in GitHub under the docs/ directory.

I am not a professional technical writer and as the developer of this software I can often make assumptions of knowledge that you as a user reading this may not have. Improvements to the documentation are always welcome, if you have suggestions for the documentation please submit pull requests to the main branch.