Question

I’ve an application that uses Maven to build a JAR with the maven-assembly-plugin.

The project includes a list of dependencies and one of these is another Maven project.
I’m developing with Eclipse and when I run the project everything works fine. When I build with the Maven goal assembly:assembly, it makes the JAR but when I run the JAR it gives me this error:

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
    The method configure(Map<String,String>) of type SMTPMailService must 
      override a superclass method
    at rey.sto.utils.mail.SMTPMailService.configure(SMTPMailService.java:89)
    at com.ppl_sftp.transfer.FileTransfer.startTransfer(FileTransfer.java:232)
    at com.ppl_sftp.transfer.MainApp.main(MainApp.java:33)

Here is the pom.xml file of the main project:

<?xml version="1.0" encoding="UTF-8"?>
<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.ppl-sftp</groupId>
<artifactId>transfer</artifactId>
<packaging>jar</packaging>
<version>0.0.1-SNAPSHOT</version>

<name>A Camel Route</name>
<url>http://www.myorganization.org</url>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
</properties>

<dependencies>
    <!-- logging -->

    <!-- testing -->
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-core</artifactId>
        <version>2.10.0</version>
        <type>jar</type>
        <optional>false</optional>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.6.6</version>
        <type>jar</type>
        <optional>false</optional>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.6.6</version>
        <type>jar</type>
        <optional>false</optional>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.16</version>
        <type>jar</type>
        <optional>false</optional>
    </dependency>
    <dependency>
        <groupId>org.xerial</groupId>
        <artifactId>sqlite-jdbc</artifactId>
        <version>3.7.2</version>
        <type>jar</type>
        <optional>false</optional>
    </dependency>
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-test</artifactId>
        <version>2.10.0</version>
        <type>jar</type>
        <scope>test</scope>
        <optional>false</optional>
    </dependency>
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-ftp</artifactId>
        <version>2.9.2</version>
        <type>jar</type>
        <optional>false</optional>
    </dependency>

    <dependency>
        <groupId>my-utils</groupId>
        <artifactId>my-utils</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </dependency>
    <dependency>
         <groupId>javax.activation</groupId>
         <artifactId>activation</artifactId>
         <version>1.1</version>
        </dependency>
    <dependency>
        <groupId>com.sun.mail</groupId>
        <artifactId>javax.mail</artifactId>
        <version>1.4.5</version>
    </dependency>
</dependencies>

<build>
    <defaultGoal>install</defaultGoal>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.5</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
            </configuration>
        </plugin>
        <!-- allows the route to be ran via 'mvn camel:run' -->
        <plugin>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-maven-plugin</artifactId>
            <version>2.10.0</version>
        </plugin>
        <!-- Allows the example to be run via 'mvn compile exec:java' -->
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>exec-maven-plugin</artifactId>
            <version>1.2.1</version>
            <configuration>
                <mainClass>com.ppl_sftp.transfer.MainApp</mainClass>
                <includePluginDependencies>false</includePluginDependencies>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-assembly-plugin</artifactId>
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>com.ppl_sftp.transfer.MainApp</mainClass>
                    </manifest>
                </archive>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
            </configuration>
        </plugin>
    </plugins>
</build>

and this is the pom of the my-utils project dependency:

<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>rey-sto-utils</groupId>
<artifactId>rey-sto-utils</artifactId>
<version>0.0.1-SNAPSHOT</version>
<build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.5</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
            </configuration>
        </plugin>
    </plugins>
</build>
<dependencies>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>2.0-beta2</version>
        <type>pom</type>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.21</version>
    </dependency>
    <dependency>
        <groupId>ojdbc6</groupId>
        <artifactId>ojdbc6</artifactId>
        <version>6</version>
    </dependency>
    <dependency>
        <groupId>javax.activation</groupId>
        <artifactId>activation</artifactId>
        <version>1.1</version>
    </dependency>
    <dependency>
        <groupId>com.sun.mail</groupId>
        <artifactId>javax.mail</artifactId>
        <version>1.4.5</version>
    </dependency>
</dependencies>

The problem is related to the Java mail dependency. As you can see I’ve used com.sun.mail but I saw some other different libraries that correspond to javax.mail.

Maybe I’m missing something in my poms, such as configuration parameters or plugins.

I’ve also tried to put in my local repository a mail.jar that works fine in other projects but I get the same error.

Answer 1

The “Unresolved compilation problem” comes from a class file in your utils project that Eclipse has compiled, but where Eclipse was unable to compile it properly.

The reason you are seeing different results from Eclipse and Maven is that they are using different versions of the class file. Eclipse is doing workspace resolution, so it’s using the version of SMTPMailService in utils/target/classes. Maven is resolving the utils jar from your local Maven repository, which was put there by running mvn install while you had compile errors in Eclipse.

Try running mvn clean install in the utils project (clean to remove any class files generated by Eclipse, install to replace the jar in your local repository). Then rebuild your assembly.