Possible for IDE's to resolve Scala classes in Java using Maven?

I have a project with mixed Java and Scala sources, following the instructions on this page, which works when running Maven from the command line.

However, people using IDEs like IDE开发者_如何学编程A and Netbeans have problems resolving Scala classes in Java code (but not the other way around, thanks to the nice plugins available). Is there a way to resolve them?

Note: I can build from the command line just fine; the Scala classes are compiled before the Java classes. I just want the IDE to recognize this as well. I could create a separate module for the Scala classes to resolve this problem, but it seems like overkill to me.

Note: In IDEA, I have "Compile Scala classes first" and that still does not do the trick.

Update: Here are the versions I'm using: scala-library 2.8.0 maven-scala-plugin 2.12 IDEA 9.0 Ultimate with latest scala plugin from plugin repos Netbeans 6.9 with scala nightly plugin

Which versions (of Scala, the IDEs, the Scala plugins) are you using?

I had the same issues when I started using Scala 2.7 around 9 months ago. While I haven't tried a mixed project recently, my understanding was that the issues would be resolved in Scala 2.8. It may be worth trying Eclipse 3.5.2 with Scala 2.8 -- my impression is that the Eclipse plugin is keeping up with changes in 2.8 better than the other IDE plugins (but I could be wrong).

I have being trying to figure out how to work with Eclipse Indigo + Scala IDE 2.9, m2eclipse, mix of scala 2.9 + jdk1.7 without luck.

I found out that using maven eclipse plugin (mvn eclipse:eclipse) and importing the project as eclipse project (not maven project) with the below customization cleaned up the error marks.

<plugin>
    <groupId>org.scala-tools</groupId>
    <artifactId>maven-scala-plugin</artifactId>

    <executions>
        <execution>
            <id>scala-compile-first</id>
            <phase>process-resources</phase>
            <goals>
                <goal>add-source</goal>
                <goal>compile</goal>
            </goals>
        </execution>
        <execution>
            <id>scala-test-compile</id>
            <phase>process-test-resources</phase>
            <goals>
                <goal>testCompile</goal>
            </goals>
        </execution>
    </executions>
</plugin>

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>build-helper-maven-plugin</artifactId>

    <executions>
        <execution>
            <id>add-source</id>
            <phase>generate-sources</phase>
            <goals>
                <goal>add-source</goal>
            </goals>
            <configuration>
                <sources>
                    <source>src/main/scala</source>
                </sources>
            </configuration>
        </execution>
        <execution>
            <id>add-test-source</id>
            <phase>generate-sources</phase>
            <goals>
                <goal>add-test-source</goal>
            </goals>
            <configuration>
                <sources>
                    <source>src/test/scala</source>
                </sources>
            </configuration>
        </execution>
    </executions    
</plugin>

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-eclipse-plugin</artifactId>
    <version>2.8</version>

    <configuration>
        <downloadSources>true</downloadSources>
        <downloadJavadocs>true</downloadJavadocs>
        <projectnatures>
            <projectnature>org.scala-ide.sdt.core.scalanature</projectnature>
            <projectnature>org.eclipse.jdt.core.javanature</projectnature>
        </projectnatures>
        <buildcommands>
            <buildcommand>org.scala-ide.sdt.core.scalabuilder</buildcommand>
        </buildcommands>
        <classpathContainers>
            <classpathContainer>org.scala-ide.sdt.launching.SCALA_CONTAINER"</classpathContainer>
            <classpathContainer>org.eclipse.jdt.launching.JRE_CONTAINER</classpathContainer>
        </classpathContainers>
        <excludes>
            <exclude>org.scala-lang:scala-library</exclude>
            <exclude>org.scala-lang:scala-compiler</exclude>
        </excludes>
        <sourceIncludes>
            <sourceInclude>**/*.scala</sourceInclude>
            <sourceInclude>**/*.java</sourceInclude>
        </sourceIncludes>
    </configuration>
</plugin>