You are viewing a plain text version of this content. The canonical link for it is here.
Posted to users@maven.apache.org by pieter claassen <pi...@claassen.co.uk> on 2008/10/24 10:57:09 UTC
POM problem
Hello,
My maven setup worked fine and then I moved to an artifactory
repository (because db4o is not available in maven yet).
Suddenly I had problems compiling my app (error below)
[ERROR] BUILD FAILURE
[INFO]
------------------------------------------------------------------------
[INFO] Compilation failure
/Users/pclaassen/Documents/workspace/tmp/src/main/java/com/musmato/dao/
BaseFactory.java:[50,43] type parameters of <T>T cannot be determined;
no unique maximal instance exists for type variable T with upper
bounds T,java.lang.Object
/Users/pclaassen/Documents/workspace/tmp/src/main/java/com/musmato/dao/
BaseFactory.java:[50,43] type parameters of <T>T cannot be determined;
no unique maximal instance exists for type variable T with upper
bounds T,java.lang.Object
This looks like a java generics issue but:
zorgon:tmp pclaassen$ java -version
java version "1.6.0_07"
Java(TM) SE Runtime Environment (build 1.6.0_07-b06-153)
Java HotSpot(TM) 64-Bit Server VM (build 1.6.0_07-b06-57, mixed mode)
So I am on the latest version of java.
Here is my slightly sanitized pom.xml.
Does anybody have some advice?
<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/maven-v4_0_0.xsd
">
<modelVersion>4.0.0</modelVersion>
<groupId>com.musmato</groupId>
<artifactId>practice</artifactId>
<packaging>war</packaging>
<version>1.0</version>
<!-- TODO project name -->
<name>practice101</name>
<description></description>
<!-- TODO
<organization>
<name>company name</name>
<url>company url</url>
</organization>
-->
<repositories>
<repository>
<id>central</id>
<url>http://192.168.1.100:8081/artifactory/repo</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
<repository>
<id>snapshots</id>
<url>http://192.168.1.100k:8081/artifactory/repo</url>
<releases>
<enabled>false</enabled>
</releases>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>central</id>
<url>http://192.168.1.100:8081/artifactory/plugins-releases</
url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>snapshots</id>
<url>http://192.168.1.100k:8081/artifactory/plugins-
snapshots</url>
<releases>
<enabled>false</enabled>
</releases>
</pluginRepository>
</pluginRepositories>
<licenses>
<license>
<name>The Apache Software License, Version
2.0</name>
<url>http://www.apache.org/licenses/LICENSE-2.0.txt
</url>
<distribution>repo</distribution>
</license>
</licenses>
<dependencies>
<!-- WICKET DEPENDENCIES -->
<dependency>
<groupId>org.apache.wicket</groupId>
<artifactId>wicket</artifactId>
<version>${wicket.version}</version>
</dependency>
<dependency>
<groupId>com.db4o</groupId>
<artifactId>db4o-java5</artifactId>
<version>7.4.63.11890</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.4.2</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.15</version>
</dependency>
<dependency>
<groupId>javax.jms</groupId>
<artifactId>jms</artifactId>
<version>1.1</version>
</dependency>
<dependency>
<groupId>com.sun.jdmk</groupId>
<artifactId>jmxtools</artifactId>
<version>1.2.1</version>
</dependency>
<dependency>
<groupId>com.sun.jmx</groupId>
<artifactId>jmxri</artifactId>
<version>1.2.1</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.2</version>
<!--<scope>test</scope>-->
</dependency>
<dependency>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty</artifactId>
<version>${jetty.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty-util</artifactId>
<version>${jetty.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty-management</artifactId>
<version>${jetty.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>jasperreports</groupId>
<artifactId>jasperreports</artifactId>
<version>3.1.0</version>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<filtering>false</filtering>
<directory>src/main/resources</
directory>
</resource>
<resource>
<filtering>false</filtering>
<directory>src/main/java</directory>
<includes>
<include>**</include>
</includes>
<excludes>
<exclude>**/*.java</exclude>
</excludes>
</resource>
</resources>
<testResources>
<testResource>
<filtering>false</filtering>
<directory>src/test/java</directory>
<includes>
<include>**</include>
</includes>
<excludes>
<exclude>**/*.java</exclude>
</excludes>
</testResource>
</testResources>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>jasperreports-maven-plugin</artifactId>
<version>1.0-beta-2-SNAPSHOT</version>
<executions>
<execution>
<goals>
<goal>compile-reports</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<configuration>
<filesets>
<fileset>
<directory>*</directory>
<excludes>
<exclude>**/.svn</exclude>
</excludes>
</fileset>
</filesets>
</configuration>
</plugin>
<plugin>
<groupId>org.mortbay.jetty</groupId>
<artifactId>maven-jetty-plugin</
artifactId>
<configuration>
<scanIntervalSeconds>15</
scanIntervalSeconds>
<contextPath>/
practice</contextPath>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.5</source>
<target>1.5</target>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<wicket.version>1.3.5</wicket.version>
<jetty.version>6.1.4</jetty.version>
</properties>
</project>
pieter claassen
pieter@claassen.co.uk
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
For additional commands, e-mail: users-help@maven.apache.org
Re: POM problem
Posted by Nick Stolwijk <ni...@gmail.com>.
I see you already have that... It seems it is a code issue, see [1]
[1] http://forums.sun.com/thread.jspa?threadID=728517
Hth,
Nick Stolwijk
~Java Developer~
Iprofs BV.
Claus Sluterweg 125
2012 WS Haarlem
www.iprofs.nl
On Fri, Oct 24, 2008 at 11:00 AM, Nick Stolwijk <ni...@gmail.com> wrote:
> The default for the compiler plugin is Java 1.4, regardless of your jvm.
>
> Add this to your pom:
> <build>
> <plugins>
> <plugin>
> <groupId>org.apache.maven.plugins</groupId>
> <artifactId>maven-compiler-plugin</artifactId>
> <configuration>
> <source>1.5</source>
> <target>1.5</target>
> </configuration>
> </plugin>
> </build>
>
> Hth,
>
> Nick Stolwijk
> ~Java Developer~
>
> Iprofs BV.
> Claus Sluterweg 125
> 2012 WS Haarlem
> www.iprofs.nl
>
>
>
> On Fri, Oct 24, 2008 at 10:57 AM, pieter claassen <pi...@claassen.co.uk> wrote:
>> Hello,
>>
>> My maven setup worked fine and then I moved to an artifactory repository
>> (because db4o is not available in maven yet).
>>
>> Suddenly I had problems compiling my app (error below)
>>
>> [ERROR] BUILD FAILURE
>> [INFO]
>> ------------------------------------------------------------------------
>> [INFO] Compilation failure
>> /Users/pclaassen/Documents/workspace/tmp/src/main/java/com/musmato/dao/BaseFactory.java:[50,43]
>> type parameters of <T>T cannot be determined; no unique maximal instance
>> exists for type variable T with upper bounds T,java.lang.Object
>>
>>
>>
>> /Users/pclaassen/Documents/workspace/tmp/src/main/java/com/musmato/dao/BaseFactory.java:[50,43]
>> type parameters of <T>T cannot be determined; no unique maximal instance
>> exists for type variable T with upper bounds T,java.lang.Object
>>
>> This looks like a java generics issue but:
>>
>> zorgon:tmp pclaassen$ java -version
>> java version "1.6.0_07"
>> Java(TM) SE Runtime Environment (build 1.6.0_07-b06-153)
>> Java HotSpot(TM) 64-Bit Server VM (build 1.6.0_07-b06-57, mixed mode)
>>
>>
>> So I am on the latest version of java.
>>
>> Here is my slightly sanitized pom.xml.
>>
>> Does anybody have some advice?
>>
>>
>> <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/maven-v4_0_0.xsd">
>>
>> <modelVersion>4.0.0</modelVersion>
>> <groupId>com.musmato</groupId>
>> <artifactId>practice</artifactId>
>> <packaging>war</packaging>
>> <version>1.0</version>
>> <!-- TODO project name -->
>> <name>practice101</name>
>> <description></description>
>>
>> <!-- TODO
>> <organization>
>> <name>company name</name>
>> <url>company url</url>
>> </organization>
>> -->
>> <repositories>
>> <repository>
>> <id>central</id>
>> <url>http://192.168.1.100:8081/artifactory/repo</url>
>> <snapshots>
>> <enabled>false</enabled>
>> </snapshots>
>> </repository>
>> <repository>
>> <id>snapshots</id>
>> <url>http://192.168.1.100k:8081/artifactory/repo</url>
>> <releases>
>> <enabled>false</enabled>
>> </releases>
>> </repository>
>> </repositories>
>>
>> <pluginRepositories>
>> <pluginRepository>
>> <id>central</id>
>> <url>http://192.168.1.100:8081/artifactory/plugins-releases</url>
>> <snapshots>
>> <enabled>false</enabled>
>> </snapshots>
>> </pluginRepository>
>> <pluginRepository>
>> <id>snapshots</id>
>> <url>http://192.168.1.100k:8081/artifactory/plugins-snapshots</url>
>> <releases>
>> <enabled>false</enabled>
>> </releases>
>> </pluginRepository>
>> </pluginRepositories>
>>
>>
>> <licenses>
>> <license>
>> <name>The Apache Software License, Version 2.0</name>
>>
>> <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
>> <distribution>repo</distribution>
>> </license>
>> </licenses>
>>
>>
>> <dependencies>
>> <!-- WICKET DEPENDENCIES -->
>> <dependency>
>> <groupId>org.apache.wicket</groupId>
>> <artifactId>wicket</artifactId>
>> <version>${wicket.version}</version>
>> </dependency>
>> <dependency>
>> <groupId>com.db4o</groupId>
>> <artifactId>db4o-java5</artifactId>
>> <version>7.4.63.11890</version>
>> <scope>compile</scope>
>> </dependency>
>> <dependency>
>> <groupId>org.slf4j</groupId>
>> <artifactId>slf4j-log4j12</artifactId>
>> <version>1.4.2</version>
>> </dependency>
>> <dependency>
>> <groupId>log4j</groupId>
>> <artifactId>log4j</artifactId>
>> <version>1.2.15</version>
>> </dependency>
>> <dependency>
>> <groupId>javax.jms</groupId>
>> <artifactId>jms</artifactId>
>> <version>1.1</version>
>> </dependency>
>> <dependency>
>> <groupId>com.sun.jdmk</groupId>
>> <artifactId>jmxtools</artifactId>
>> <version>1.2.1</version>
>> </dependency>
>> <dependency>
>> <groupId>com.sun.jmx</groupId>
>> <artifactId>jmxri</artifactId>
>> <version>1.2.1</version>
>> </dependency>
>> <dependency>
>> <groupId>junit</groupId>
>> <artifactId>junit</artifactId>
>> <version>3.8.2</version>
>> <!--<scope>test</scope>-->
>> </dependency>
>>
>> <dependency>
>> <groupId>org.mortbay.jetty</groupId>
>> <artifactId>jetty</artifactId>
>> <version>${jetty.version}</version>
>> <scope>provided</scope>
>> </dependency>
>> <dependency>
>> <groupId>org.mortbay.jetty</groupId>
>> <artifactId>jetty-util</artifactId>
>> <version>${jetty.version}</version>
>> <scope>provided</scope>
>> </dependency>
>> <dependency>
>> <groupId>org.mortbay.jetty</groupId>
>> <artifactId>jetty-management</artifactId>
>> <version>${jetty.version}</version>
>> <scope>provided</scope>
>> </dependency>
>> <dependency>
>> <groupId>jasperreports</groupId>
>> <artifactId>jasperreports</artifactId>
>> <version>3.1.0</version>
>> </dependency>
>> </dependencies>
>>
>> <build>
>>
>> <resources>
>> <resource>
>> <filtering>false</filtering>
>> <directory>src/main/resources</directory>
>> </resource>
>> <resource>
>> <filtering>false</filtering>
>> <directory>src/main/java</directory>
>> <includes>
>> <include>**</include>
>> </includes>
>> <excludes>
>> <exclude>**/*.java</exclude>
>> </excludes>
>> </resource>
>> </resources>
>> <testResources>
>> <testResource>
>> <filtering>false</filtering>
>> <directory>src/test/java</directory>
>> <includes>
>> <include>**</include>
>> </includes>
>> <excludes>
>> <exclude>**/*.java</exclude>
>> </excludes>
>> </testResource>
>> </testResources>
>>
>> <plugins>
>>
>>
>> <plugin>
>> <groupId>org.codehaus.mojo</groupId>
>> <artifactId>jasperreports-maven-plugin</artifactId>
>> <version>1.0-beta-2-SNAPSHOT</version>
>> <executions>
>> <execution>
>> <goals>
>> <goal>compile-reports</goal>
>> </goals>
>> </execution>
>> </executions>
>> </plugin>
>>
>> <plugin>
>> <artifactId>maven-clean-plugin</artifactId>
>> <configuration>
>> <filesets>
>> <fileset>
>> <directory>*</directory>
>> <excludes>
>> <exclude>**/.svn</exclude>
>> </excludes>
>> </fileset>
>> </filesets>
>> </configuration>
>> </plugin>
>>
>> <plugin>
>> <groupId>org.mortbay.jetty</groupId>
>> <artifactId>maven-jetty-plugin</artifactId>
>> <configuration>
>>
>> <scanIntervalSeconds>15</scanIntervalSeconds>
>>
>> <contextPath>/practice</contextPath>
>> </configuration>
>> </plugin>
>> <plugin>
>> <groupId>org.apache.maven.plugins</groupId>
>> <artifactId>maven-compiler-plugin</artifactId>
>> <configuration>
>> <source>1.5</source>
>> <target>1.5</target>
>> </configuration>
>> </plugin>
>> </plugins>
>>
>>
>> </build>
>> <properties>
>> <wicket.version>1.3.5</wicket.version>
>> <jetty.version>6.1.4</jetty.version>
>> </properties>
>>
>> </project>
>>
>> pieter claassen
>> pieter@claassen.co.uk
>>
>>
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
>> For additional commands, e-mail: users-help@maven.apache.org
>>
>>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
For additional commands, e-mail: users-help@maven.apache.org
Re: POM problem
Posted by Nick Stolwijk <ni...@gmail.com>.
The default for the compiler plugin is Java 1.4, regardless of your jvm.
Add this to your pom:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.5</source>
<target>1.5</target>
</configuration>
</plugin>
</build>
Hth,
Nick Stolwijk
~Java Developer~
Iprofs BV.
Claus Sluterweg 125
2012 WS Haarlem
www.iprofs.nl
On Fri, Oct 24, 2008 at 10:57 AM, pieter claassen <pi...@claassen.co.uk> wrote:
> Hello,
>
> My maven setup worked fine and then I moved to an artifactory repository
> (because db4o is not available in maven yet).
>
> Suddenly I had problems compiling my app (error below)
>
> [ERROR] BUILD FAILURE
> [INFO]
> ------------------------------------------------------------------------
> [INFO] Compilation failure
> /Users/pclaassen/Documents/workspace/tmp/src/main/java/com/musmato/dao/BaseFactory.java:[50,43]
> type parameters of <T>T cannot be determined; no unique maximal instance
> exists for type variable T with upper bounds T,java.lang.Object
>
>
>
> /Users/pclaassen/Documents/workspace/tmp/src/main/java/com/musmato/dao/BaseFactory.java:[50,43]
> type parameters of <T>T cannot be determined; no unique maximal instance
> exists for type variable T with upper bounds T,java.lang.Object
>
> This looks like a java generics issue but:
>
> zorgon:tmp pclaassen$ java -version
> java version "1.6.0_07"
> Java(TM) SE Runtime Environment (build 1.6.0_07-b06-153)
> Java HotSpot(TM) 64-Bit Server VM (build 1.6.0_07-b06-57, mixed mode)
>
>
> So I am on the latest version of java.
>
> Here is my slightly sanitized pom.xml.
>
> Does anybody have some advice?
>
>
> <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/maven-v4_0_0.xsd">
>
> <modelVersion>4.0.0</modelVersion>
> <groupId>com.musmato</groupId>
> <artifactId>practice</artifactId>
> <packaging>war</packaging>
> <version>1.0</version>
> <!-- TODO project name -->
> <name>practice101</name>
> <description></description>
>
> <!-- TODO
> <organization>
> <name>company name</name>
> <url>company url</url>
> </organization>
> -->
> <repositories>
> <repository>
> <id>central</id>
> <url>http://192.168.1.100:8081/artifactory/repo</url>
> <snapshots>
> <enabled>false</enabled>
> </snapshots>
> </repository>
> <repository>
> <id>snapshots</id>
> <url>http://192.168.1.100k:8081/artifactory/repo</url>
> <releases>
> <enabled>false</enabled>
> </releases>
> </repository>
> </repositories>
>
> <pluginRepositories>
> <pluginRepository>
> <id>central</id>
> <url>http://192.168.1.100:8081/artifactory/plugins-releases</url>
> <snapshots>
> <enabled>false</enabled>
> </snapshots>
> </pluginRepository>
> <pluginRepository>
> <id>snapshots</id>
> <url>http://192.168.1.100k:8081/artifactory/plugins-snapshots</url>
> <releases>
> <enabled>false</enabled>
> </releases>
> </pluginRepository>
> </pluginRepositories>
>
>
> <licenses>
> <license>
> <name>The Apache Software License, Version 2.0</name>
>
> <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
> <distribution>repo</distribution>
> </license>
> </licenses>
>
>
> <dependencies>
> <!-- WICKET DEPENDENCIES -->
> <dependency>
> <groupId>org.apache.wicket</groupId>
> <artifactId>wicket</artifactId>
> <version>${wicket.version}</version>
> </dependency>
> <dependency>
> <groupId>com.db4o</groupId>
> <artifactId>db4o-java5</artifactId>
> <version>7.4.63.11890</version>
> <scope>compile</scope>
> </dependency>
> <dependency>
> <groupId>org.slf4j</groupId>
> <artifactId>slf4j-log4j12</artifactId>
> <version>1.4.2</version>
> </dependency>
> <dependency>
> <groupId>log4j</groupId>
> <artifactId>log4j</artifactId>
> <version>1.2.15</version>
> </dependency>
> <dependency>
> <groupId>javax.jms</groupId>
> <artifactId>jms</artifactId>
> <version>1.1</version>
> </dependency>
> <dependency>
> <groupId>com.sun.jdmk</groupId>
> <artifactId>jmxtools</artifactId>
> <version>1.2.1</version>
> </dependency>
> <dependency>
> <groupId>com.sun.jmx</groupId>
> <artifactId>jmxri</artifactId>
> <version>1.2.1</version>
> </dependency>
> <dependency>
> <groupId>junit</groupId>
> <artifactId>junit</artifactId>
> <version>3.8.2</version>
> <!--<scope>test</scope>-->
> </dependency>
>
> <dependency>
> <groupId>org.mortbay.jetty</groupId>
> <artifactId>jetty</artifactId>
> <version>${jetty.version}</version>
> <scope>provided</scope>
> </dependency>
> <dependency>
> <groupId>org.mortbay.jetty</groupId>
> <artifactId>jetty-util</artifactId>
> <version>${jetty.version}</version>
> <scope>provided</scope>
> </dependency>
> <dependency>
> <groupId>org.mortbay.jetty</groupId>
> <artifactId>jetty-management</artifactId>
> <version>${jetty.version}</version>
> <scope>provided</scope>
> </dependency>
> <dependency>
> <groupId>jasperreports</groupId>
> <artifactId>jasperreports</artifactId>
> <version>3.1.0</version>
> </dependency>
> </dependencies>
>
> <build>
>
> <resources>
> <resource>
> <filtering>false</filtering>
> <directory>src/main/resources</directory>
> </resource>
> <resource>
> <filtering>false</filtering>
> <directory>src/main/java</directory>
> <includes>
> <include>**</include>
> </includes>
> <excludes>
> <exclude>**/*.java</exclude>
> </excludes>
> </resource>
> </resources>
> <testResources>
> <testResource>
> <filtering>false</filtering>
> <directory>src/test/java</directory>
> <includes>
> <include>**</include>
> </includes>
> <excludes>
> <exclude>**/*.java</exclude>
> </excludes>
> </testResource>
> </testResources>
>
> <plugins>
>
>
> <plugin>
> <groupId>org.codehaus.mojo</groupId>
> <artifactId>jasperreports-maven-plugin</artifactId>
> <version>1.0-beta-2-SNAPSHOT</version>
> <executions>
> <execution>
> <goals>
> <goal>compile-reports</goal>
> </goals>
> </execution>
> </executions>
> </plugin>
>
> <plugin>
> <artifactId>maven-clean-plugin</artifactId>
> <configuration>
> <filesets>
> <fileset>
> <directory>*</directory>
> <excludes>
> <exclude>**/.svn</exclude>
> </excludes>
> </fileset>
> </filesets>
> </configuration>
> </plugin>
>
> <plugin>
> <groupId>org.mortbay.jetty</groupId>
> <artifactId>maven-jetty-plugin</artifactId>
> <configuration>
>
> <scanIntervalSeconds>15</scanIntervalSeconds>
>
> <contextPath>/practice</contextPath>
> </configuration>
> </plugin>
> <plugin>
> <groupId>org.apache.maven.plugins</groupId>
> <artifactId>maven-compiler-plugin</artifactId>
> <configuration>
> <source>1.5</source>
> <target>1.5</target>
> </configuration>
> </plugin>
> </plugins>
>
>
> </build>
> <properties>
> <wicket.version>1.3.5</wicket.version>
> <jetty.version>6.1.4</jetty.version>
> </properties>
>
> </project>
>
> pieter claassen
> pieter@claassen.co.uk
>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
> For additional commands, e-mail: users-help@maven.apache.org
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
For additional commands, e-mail: users-help@maven.apache.org