Question

Strange behavior, sometimes I can package my project, most of the time I cannot.
The problem happens in android:dex:

$ mvn clean android:dex
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building Test 0.0.1
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.3:clean (default-clean) @ test ---
[INFO] Deleting file set: /home/danny/workspace/test/target (included: [**], excluded: [])
[INFO] 
[INFO] --- android-maven-plugin:3.3.2:dex (default-cli) @ test ---
[INFO] /usr/lib/jvm/java-6-sun-1.6.0.26/jre/bin/java [-Xmx1024M, -jar, /home/danny/.bin/android-sdk-linux/platform-tools/lib/dx.jar, --dex, --output=/home/danny/workspace/test/target/classes.dex, /home/danny/workspace/test/target/classes]
[INFO] 
[INFO] UNEXPECTED TOP-LEVEL EXCEPTION:
[INFO] java.lang.RuntimeException: /home/danny/workspace/test/target/classes: file not found
[INFO]  at com.android.dx.util.FileUtils.readFile(FileUtils.java:55)
[INFO]  at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:134)
[INFO]  at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:109)
[INFO]  at com.android.dx.command.dexer.Main.processOne(Main.java:418)
[INFO]  at com.android.dx.command.dexer.Main.processAllFiles(Main.java:329)
[INFO]  at com.android.dx.command.dexer.Main.run(Main.java:206)
[INFO]  at com.android.dx.command.dexer.Main.main(Main.java:174)
[INFO]  at com.android.dx.command.Main.main(Main.java:91)
[INFO] 1 error; aborting
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.914s
[INFO] Finished at: Sun Oct 07 20:17:03 CEST 2012
[INFO] Final Memory: 7M/88M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal com.jayway.maven.plugins.android.generation2:android-maven-plugin:3.3.2:dex (default-cli) on project test: MojoExecutionException: ANDROID-040-001: Could not execute: Command = /bin/sh -c cd /home/danny/workspace/test && /usr/lib/jvm/java-6-sun-1.6.0.26/jre/bin/java -Xmx1024M -jar /home/danny/.bin/android-sdk-linux/platform-tools/lib/dx.jar --dex --output=/home/danny/workspace/test/target/classes.dex /home/danny/workspace/test/target/classes, Result = 1 -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

I cannot find any information on this…
My 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>
    <packaging>apk</packaging>
    <artifactId>test</artifactId>
    <groupId>com.example</groupId>
    <name>Test</name>
    <version>0.0.1</version>

    <dependencies>
        <dependency>
            <artifactId>android</artifactId>
            <groupId>com.google.android</groupId>
            <scope>provided</scope>
            <version>2.2.1</version>
        </dependency>
        <dependency>
            <artifactId>junit</artifactId>
            <groupId>junit</groupId>
            <scope>test</scope>
            <version>4.10</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.5.1</version>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>android-maven-plugin</artifactId>
                <configuration>
                    <assetsDirectory>src/main/assets</assetsDirectory>
                    <resourceDirectory>src/main/resources</resourceDirectory>
                    <sdk>
                        <platform>8</platform>
                    </sdk>
                </configuration>
                <extensions>true</extensions>
                <groupId>com.jayway.maven.plugins.android.generation2</groupId>
                <version>3.3.2</version>
            </plugin>    
        </plugins>
    </build>

</project>

EDIT

Running mvn package results in:

$ mvn package
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building Test 0.0.1
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- android-maven-plugin:3.3.2:generate-sources (default-generate-sources) @ test ---
[INFO] ANDROID-904-002: Found aidl files: Count = 0
[INFO] ANDROID-904-002: Found aidl files: Count = 0
[INFO] /home/danny/.bin/android-sdk-linux/platform-tools/aapt [package, -m, -J, /home/danny/workspace/test/target/generated-sources/r, -M, /home/danny/workspace/test/AndroidManifest.xml, -S, /home/danny/workspace/test/src/main/resources, --auto-add-overlay, -A, /home/danny/workspace/test/src/main/assets, -I, /home/danny/.bin/android-sdk-linux/platforms/android-8/android.jar]
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ test ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 8 resources
[INFO] skip non existing resourceDirectory /home/danny/workspace/test/target/generated-sources/extracted-dependencies/src/main/resources
[INFO] 
[INFO] --- maven-compiler-plugin:2.5.1:compile (default-compile) @ test ---
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!
[INFO] Compiling 3 source files to /home/danny/workspace/test/target/classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] /home/danny/workspace/test/src/main/java/com/example/test/gui/MainActivity.java:[17,18] package R does not exist
[ERROR] /home/danny/workspace/test/src/main/java/com/example/test/gui/MainActivity.java:[26,29] package R does not exist
[INFO] 2 errors 
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.960s
[INFO] Finished at: Sun Oct 07 22:40:35 CEST 2012
[INFO] Final Memory: 13M/86M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.5.1:compile (default-compile) on project test: Compilation failure: Compilation failure:
[ERROR] /home/danny/workspace/test/src/main/java/com/example/test/gui/MainActivity.java:[17,18] package R does not exist
[ERROR] /home/danny/workspace/test/src/main/java/com/example/test/gui/MainActivity.java:[26,29] package R does not exist
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

Answer 1

The generated R file used the package declaration com.example.test (which is the groupId of my project) and I tried to access it in the class com.example.test.gui.MainActivity. So I needed to import com.example.test.R explicitly.