Colbert Philippe created MCOMPILER-337:
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Summary: Using old-style Jar files with Java9 Module project,
Classpath and Module-path are mixed up!
Key: MCOMPILER-337
URL: https://issues.apache.org/jira/browse/MCOMPILER-337
Project: Maven Compiler Plugin
Issue Type: Bug
Affects Versions: 3.7.0
Reporter: Colbert Philippe
I'm trying to use Eclipse (4.8M4) with Maven to practice Java9 module.
I already contacted Maven to ask what version of Maven to use with Java 9
module feature. They recommended the latest version: Maven 3.5.0 (latest) with
the Maven plug-in: maven-compiler-plugin 3.7.0, which is what I'm using. I'm
also using Java JDK 9.
I want to report a problem with Eclipse when working with Java 9 module
feature. It's not a big problem but it's big enough to prevent the use of
Eclipse with Java 9 modules. The problem is with Eclipse, not Maven. The Maven
version that I'm using works fine! I tested it!
I created two identical projects with Java 9 module. The two projects make use
of a few old-style Jar files by importing them as default module (as prescribed
by the makers of Java 9). The jar files are: ant.jar,
commons-beanutils-1.9.3.jar, commons-collections4-4.1.jar,
commons-lang3-3.7.jar.
* The first project is a small project built from the command-line with a
text-editor. It's a Java 9 module project (has a module-info.java) and makes
use of these 4 libray jar files in the matter prescribed by the Java 9
documentation. This project compile and works. All Jar files are put the the
module-path of the project and their respective 'requires' statement is in the
module-info.java file. (see below)
module canada.ontario {
exports canada.ontario;
requires org.apache.commons.lang3;
requires commons.collections4;
requires commons.beanutils;
}
** The second project is identical to the first one but is built using Eclipse
& Maven (versions specified above). The project as created as intended with
Maven. First a parent project was created with packaging set with pom. The a
child-project was created for the module.
After the child-project was created, in the child-project POM file, I entered
the full plug-in entries to use the new 'maven-compiler-plugin' version 3.7.0.
This works because we can see its use on the compiling log display messages.
On Eclipse Workspace view, I selected the parent project root (previously
created), right clicking on the parent project, then selecting 'Maven', then
selecting 'New Maven Module Project'. This creates a Maven child project for
the new module.
- I created a 'module-info.java' with the name of the module (canada.ontario)
in the src directory.
- I also created a package with the same name as the module (canada.ontario).
- I entered the same 'exports' and 'requires' statements as displayed above.
- I also entered all the Maven dependencies to each of the four (4) libraries
stated above. I got these dependencies from the Maven repository.
- I also enabled full compile-time log-message diplay, in order to get maximum
information.
### HERE IS THE PROBLEM WHEN COMPILING THIS SECOND MAVEN CHILD-PROJECT! ###
When compiling the second child-project for the module, there is an error. I
have narrowed down the reason for the errror.
For some unknown reason, the Maven compiler plug-in DOES NOT put all the jar
dependencies under the module-path. It splits the list of dependencies between
the classpath and the module-path, WHICH IS WRONG! (see below)
[INFO] Changes detected - recompiling the module!
[DEBUG] Classpath: <----- There should be no jar under this Classpath list ***
[DEBUG] C:\Users\Colbert
Philippe\workspace\montreal\quebec.lachine\target\classes
[DEBUG] C:\Users\Colbert
Philippe\.m2\repository\org\apache\commons\commons-collections4\4.1\commons-collections4-4.1.jar
[DEBUG] C:\Users\Colbert
Philippe\.m2\repository\commons-beanutils\commons-beanutils\1.9.3\commons-beanutils-1.9.3.jar
[DEBUG] C:\Users\Colbert
Philippe\.m2\repository\commons-logging\commons-logging\1.2\commons-logging-1.2.jar
[DEBUG] C:\Users\Colbert
Philippe\.m2\repository\commons-collections\commons-collections\3.2.2\commons-collections-3.2.2.jar
[DEBUG] Modulepath: <----- All jar file dependencies should be under this
ModulePath list ***
[DEBUG] C:\Users\Colbert
Philippe\.m2\repository\org\apache\commons\commons-lang3\3.7\commons-lang3-3.7.jar
[DEBUG] Source roots:
This is the source of the error!
Since putting all the jar files under module-path works in my first
hand-created project works fine. I am certain that this is the cause of the
error.
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