The Java Module System

13 Module versions: What’s possible and what’s not

This chapter covers

• Why the module system doesn’t act on version information
• Recording version information
• Analyzing version information at run time
• Loading multiple module versions

As briefly mentioned in section 1.5.6, the JPMS doesn’t support module versions. But then what is jar --module-version good for? And didn’t section 12.3.3 show that ModuleDescriptor can at least report a module’s version? This chapter clears things up and looks at module versions from a few different angles.

We’ll first discuss in what ways the module system could support versions and why it doesn’t do that (section 13.1). It at least allows you to record and evaluate version information, though, and we’ll explore ...