Question

I have set up basic maven project in java SE, with a resource:

main 
  -java
  -resources
    -config -> database.properties

now since I don’t want this resource in the final jar, I define:

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

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.4</version>
            <configuration>
                <excludes>
                    <exclude>config/database.properties</exclude>
                </excludes>
            </configuration>
            <executions>
                <execution>
                    <id>make-jar-ultimateParser</id>
                    <phase>package</phase>
                    <goals>
                        <goal>jar</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${project.build.directory}/dist</outputDirectory>
                        <finalName>testApp</finalName>
                        <archive>
                            <compress>false</compress>
                            <!-- Manifest - MainClass & ClassPath -->
                            <manifest>
                                <mainClass>aa.bb.Class</mainClass>
                                <addClasspath>true</addClasspath>
                                <classpathPrefix>lib/</classpathPrefix>
                            </manifest>
                            <manifestEntries>
                                <Class-Path>config/database.properties</Class-Path>
                            </manifestEntries>
                        </archive>
                    </configuration>
                </execution>
            </executions>
        </plugin>
        <!-- Copy configuration files -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <version>2.6</version>
            <executions>
                <execution>
                    <id>copy-resources</id>
                    <phase>validate</phase>
                    <goals>
                        <goal>copy-resources</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${project.build.directory}/dist/config</outputDirectory>
                        <resources>
                            <resource>
                                <directory>src/main/resources/config</directory>
                            </resource>
                        </resources>
                    </configuration>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.0</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
            </configuration>
        </plugin>
    </plugins>
</build>

So the resource is on classpath and the directory with the resource is copied to the final jar.

My manifest looks like this: “Class-Path: config/database.properties”

But I’m not able to read it:

String db = "/config/database.properties";
properties = new Properties();
properties.load(getClass().getResourceAsStream(db));

I tried absolute/relative paths, getClass()/ClassLoader. Nothing. It works flawlessly in NetBeans, but that’s about it.

Answer 1

You’re misunderstanding what the Maven Resources plugin does. It simply copies resources (perhaps with transformation) into the build output directory. Where they’re then included into the build artifact (JAR, WAR, whatever).

To make this work (referencing the JAR’s directory using the Class-Path manifest entry), you need to distribute the config file separately. Or reference it using a File, and not bothering with the classpath.

A better approach is to distribute your application as an assembly, which contains the core app, any dependencies, and the configuration file. This would typically be packaged as a ZIPfile, and the user would unzip it to install.