Bug 517777

Description Torsten Horn 2017-06-04 05:55:02 EDT

I use:

 - JDK 9 build 9-ea+172
 - Maven 3.5.0
 - Eclipse Oxygen 4.7 RC3 Version 4.7.0.I20170531-2000 from 2017-05-31
 - Eclipse-Plugins:
   - Eclipse JDT (Java Development Tools) Patch with Java 9 support (BETA)
     for Oxygen development stream, 1.1.1.v20170526-0728_BETA_JAVA9
   - m2e - Maven Integration for Eclipse (includes Incubating components),
     1.8.0.20170516-2043

Create a new Jigsaw-Maven-Project:

mkdir proj-a\src\main\java\a
cd proj-a

In directory 'proj-a' the file 'pom.xml':

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>proj-a</groupId>
  <artifactId>a</artifactId>
  <version>1.0</version>
  <packaging>jar</packaging>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.6.1</version>
        <configuration>
          <source>9</source>
          <target>9</target>
          <showWarnings>true</showWarnings>
          <showDeprecation>true</showDeprecation>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

In directory 'proj-a\src\main\java' the file 'module-info.java':

module a { }

In directory 'proj-a\src\main\java\a' the file 'App.java':

package a;

public class App {
   public static void main( String[] args ) {
      System.out.println( "CLASSPATH:           " +
             System.getProperty( "java.class.path" ) );
      System.out.println( "Class / Modul:       " +
             App.class.getSimpleName() + " from " + App.class.getModule() );
      java.lang.ModuleLayer lr = App.class.getModule().getLayer();
      if( lr != null ) {
         System.out.println( "Layer.Configuration: " + lr.configuration() );
      } else {
         System.out.println( "Error:               ModuleLayer is null" );
      }
   }
}

Running the project on command line:

cd proj-a
mvn clean package
java -p target\a-1.0.jar -m a/a.App
-->  
    CLASSPATH:
    Class / Modul:       App from module a
    Layer.Configuration: jdk..., java..., ...  
-->  
Works perfect without error (CLASSPATH is empty, name from getModule() is correct, and ModuleLayer is valid).

Opening the project in IntelliJ IDEA 2017.2 EAP  
-->  
Works perfect without error (CLASSPATH is empty, name from getModule() is correct, and ModuleLayer is valid).

Importing the project in Eclipse Oxygen 4.7 RC3:  
-->  
    CLASSPATH:           ...\proj-a\target\classes
    Class / Modul:       App from unnamed module @68f7aae2
    Error:               ModuleLayer is null
-->  
All three lines are wrong.  
    
How can I avoid this errors?

I have configured Eclipse for JDK 9.
In eclipse.ini I added:
...
-vm
C:\Program Files\Java\jdk-9\bin
-vmargs
...
--add-modules=ALL-SYSTEM
--permit-illegal-access