Simpliest way to add an attribute to a jar Manifest in Maven

Question

Since the last Java update, I need to tag my applet jars manifest with the Trusted-Library attribute to avoid warning popup when javascript is communicating wit

Answer 1

As of today I needed to add some manifest attributes for signed Java applet. I found it very straightforward with maven-jar-plugin. Just put required attributes to src/main/resources/META-INF/MANIFEST.MF:

    Permissions: all-permissions

Then just configure maven-jar-plugin plugin:

        <plugin>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.4</version>
            <configuration>
                <archive>
                    <manifestFile>src/main/resources/META-INF/MANIFEST.MF</manifestFile>
                </archive>
            </configuration>
        </plugin>

And the result was:

    Manifest-Version: 1.0
    Build-Jdk: 1.7.0_51
    Built-By: bart
    Permissions: all-permissions
    Created-By: Apache Maven 3.0.5
    Archiver-Version: Plexus Archiver

    Name: name/prokop/bart/fps/util/BartDate.class
    SHA-256-Digest: XatHlhiWAK3ArocdOcVPCS3ftOcokJNlUeRhKPTHUKs=

Answer 2

You can do that with the Maven JAR Plugin during the creation of the JAR file. Add the following to your pom.xml:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <configuration>
        <archive>
            <addMavenDescriptor>false</addMavenDescriptor>
            <manifestEntries>
                <Trusted-Library>true</Trusted-Library>
            </manifestEntries>
        </archive>
    </configuration>
</plugin>
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jarsigner-plugin</artifactId>
    <version>1.2</version>
    <executions>
        <execution>
            <id>sign</id>
            <goals>
                <goal>sign</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <keystore>/path/to/testkeystore</keystore>
        <alias>myalias</alias>
        <storepass>test123</storepass>
    </configuration>
</plugin>

The main attributes as specified in the JAR File Specification are available as dedicated elements, e.g.:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <configuration>
        <archive>
            <addMavenDescriptor>false</addMavenDescriptor>
            <manifest>
                <addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>
                <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
            </manifest>
            <manifestEntries>
                <Trusted-Library>true</Trusted-Library>
            </manifestEntries>
        </archive>
    </configuration>
</plugin>

See the Maven Archiver Reference for further information.

To modify the manifest inside an existing jar file create a text file, e.g. mymanifest.mf which contains the required properties:

Trusted-Library: true

You can add the attributes of this file to an existing jar by executing the following command:

jar -cfm file-to-be-modified.jar mymanifest.mf

This will modify the manifest.mf inside the given jar.

Answer 3

I consider usage of webstart-maven-plugin the right choice here. I mean there are bugs, there are things that you might need to patch yourself, but if you're OK with that, the one plugin can do quite much for you without some ant workarounds.

For the particular problem there is a bug report with a working patch included. See: http://jira.codehaus.org/browse/MWEBSTART-213

UPDATE:

fix is included in the release: 1.0-beta-4.

going for configuration:

<updatedManifestEntries>
  <Permissions>all-permissions</Permissions>
  <Codebase>*</Codebase>
  ....
</updatedManifestEntries>

should do the job

Answer 4

In the end I just used the antrun plugin like the following, antcontrib is used to loop over the list of jars:

build-trusted.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- This is a wrapper for all the other build files. -->
<project basedir="." name="project_name">

  <target name="addTrustedLibraryProperty">
    <jar file="${jarFile}" update="true">
      <manifest>
        <attribute name="Trusted-Library" value="true" />
      </manifest>
    </jar>
  </target>

  <target name="addTrustedLibraries">
    <ac:foreach target="addTrustedLibraryProperty" param="jarFile" xmlns:ac="antlib:net.sf.antcontrib">
      <path>
        <fileset dir="target/lib" includes="**/*.jar" />
      </path>
    </ac:foreach>
  </target>

</project>

In the pom

<plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <executions>
          <execution>
            <id>add-trusted-library-attribute</id>
            <phase>package</phase>
            <configuration>
              <target>
                <ant antfile="${basedir}/build-trusted.xml">
                  <target name="addTrustedLibraries" />
                </ant>
              </target>
            </configuration>
            <goals>
              <goal>run</goal>
            </goals>
          </execution>
        </executions>
        <dependencies>
          <dependency>
            <groupId>ant-contrib</groupId>
            <artifactId>ant-contrib</artifactId>
            <version>1.0b3</version>
            <exclusions>
              <exclusion>
                <groupId>ant</groupId>
                <artifactId>ant</artifactId>
              </exclusion>
            </exclusions>
          </dependency>
          <dependency>
            <groupId>org.apache.ant</groupId>
            <artifactId>ant-nodeps</artifactId>
            <version>1.8.1</version>
          </dependency>
        </dependencies>
      </plugin>

Answer 5

You can use the jar utility to update manifest for existing .jar files like this:

echo 'Trusted-Library: true' > manifest.mf
jar uvfm your-jar-file.jar ./manifest.mf

For more information, please see the doc and the tutorial at here.