无法为 Java 9 中自动生成的模块名称派生模块描述符? [英] Unable to derive module descriptor for auto generated module names in Java 9?
问题描述
我的项目依赖于 Netty Epoll 传输.这是依赖:
<依赖><groupId>io.netty</groupId><artifactId>netty-transport-native-epoll</artifactId><version>${netty.version}</version><classifier>${epoll.os}</classifier></依赖>
此依赖项自动生成的模块名称为:
netty.transport.native.epoll
由于 native
关键字在 Java 9 中被保留,我无法将此模块作为依赖项添加到我的项目中:
模块核心{需要 netty.transport.native.epoll;}
由于:
模块未找到:netty.transport.
此外,jar 工具 --describe-module
报告以下内容:
无法为以下各项派生模块描述符:netty-transport-native-epoll-4.1.17.Final-SNAPSHOT-linux-x86_64.jarnetty.transport.native.epoll:无效的模块名称:'native' 不是Java标识符
有什么解决方法吗?(当然,发布正确的网络神器"除外).
int _;//is 会在基于 JDK9 的 javac 上抛出错误int _native;//工作正常
My project depends on Netty Epoll transport. Here is dependency:
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-transport-native-epoll</artifactId>
<version>${netty.version}</version>
<classifier>${epoll.os}</classifier>
</dependency>
The auto-generated module name for this dependency is:
netty.transport.native.epoll
And as the native
keyword is reserved in Java 9 I can't add this module as a dependency to my project:
module core {
requires netty.transport.native.epoll;
}
Due to:
module not found: netty.transport.<error>
Additionally the jar tool --describe-module
reports the following:
Unable to derive module descriptor for: netty-transport-native-epoll-4.1.17.Final-SNAPSHOT-linux-x86_64.jar netty.transport.native.epoll: Invalid module name: 'native' is not a Java identifier
Are there any workarounds? (except "release correct netty artifact", of course).
EDIT:
As the quick fix for maintainers - you can add next line to build:
<manifestEntries>
<Automatic-Module-Name>netty.transport.epoll</Automatic-Module-Name>
</manifestEntries>
The solution to this seems to be:-
- A way possible to uninterruptedly using the same artifact name with a new(different) module name could be by packaging META-INF/MANIFEST.MF of the artifact with an attribute Automatic-Module-Name which governs the name of the module to be used by the module descriptor when converted as an automatic module.
OR
- Artifact owners can add module declarations using
module-info.java
to their JAR. (this could result in a slow bottom-up migration)
Since the module declaration defined in the specs as:
A module declaration introduces a module name that can be used in other module declarations to express relationships between modules. A module name consists of one or more Java identifiers (§3.8) separated by "." tokens.
Intersetingly the declarations suggests -
In some cases, the Internet domain name may not be a valid package name. Here are some suggested conventions for dealing with these situations:
If the domain name contains a hyphen, or any other special character not allowed in an identifier (§3.8), convert it into an underscore.
If any of the resulting package name components are keywords (§3.9), append an underscore to them.
If any of the resulting package name components start with a digit, or any other character that is not allowed as an initial character of an identifier, have an underscore prefixed to the component.
But keep in mind as you do so that Underscore is a keyword in Java9
int _; // is would throw an error on javac based out of JDK9
int _native; // works fine
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