How to Resolve Java 9 Module Dependency Issues with Auto-Generated Names Containing Reserved Keywords?

Unable to Resolve Module Dependency for Auto-Generated Names in Java 9?

This issue arises when a dependency with an auto-generated module name contains the keyword "native," which is reserved in Java 9. Consequently, it becomes impossible to add it as a dependency to the module descriptor.

Solution:

To resolve this issue, two primary approaches can be considered:

1. Add Automatic Module Name Attribute:

   Artifact owners can package a META-INF/MANIFEST.MF file with the artifact that specifies the Automatic-Module-Name attribute. This attribute defines the module name to be used by the module descriptor. By setting the Automatic-Module-Name to a valid name (excluding "native"), the issue can be resolved.

2. Add Module Declaration to JAR:

   Artifact owners can add module declarations using module-info.java to their JAR files. This allows them to specify the module name explicitly, thereby avoiding the auto-generated names. However, this approach requires a gradual migration, as libraries and frameworks adopt it bottom-up.

Module Descriptor Specifications:

According to the Java 9 module declaration specifications, a module name consists of one or more Java identifiers separated by periods. This means that module names must adhere to the following rules:

• Each component must be a valid Java identifier (excluding keywords).
• If the domain name used for the module name contains special characters or keywords, it must be converted to an underscore.
• If a component starts with a digit or other characters not allowed as the first character of an identifier, an underscore must be prefixed.

Note on Underscore in Java 9:

While underscores are typically allowed as part of module names, it is important to note that underscore is now a keyword in Java 9. Therefore, identifiers containing an underscore as the initial character must be avoided. For example:

int _native; // Works fine
int _; // Causes an error in Java 9

The above is the detailed content of How to Resolve Java 9 Module Dependency Issues with Auto-Generated Names Containing Reserved Keywords?. For more information, please follow other related articles on the PHP Chinese website!