[MSHADE-183] Getting "Error creating shaded jar: java.util.jar.Attributes cannot be cast to java.lang.String" error when using ManifestResourceTransformer with Maven 3.2.5

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3
• Fix Version/s: 2.4
• Flags: Patch
• Assignee: Karl Heinz Marbaise
• Reporter: Chris Heisterkamp
• Created: 05/Jan/15 19:06
• Updated: 29/Dec/15 00:28
• Resolved: 29/May/15 21:10

Description

If you are using the ManifestResourceTransformer with empty values in the configuration you will get a "Error creating shaded jar: java.util.jar.Attributes cannot be cast to java.lang.String" error with Maven 3.2.5.

Here as an example config that causes the problem

       
<configuration>
  <transformers>
    <transformer
        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
      <manifestEntries>
        <Main-Class>com.mycompany.app.App</Main-Class>
        <Implementation-Build></Implementation-Build>
      </manifestEntries>
    </transformer>
  </transformers>
</configuration>

I'm not sure what changed in populating the manifestEntries map but it looks like the manifestEntries.entrySet() in ManifestResourceTransformer is now getting back Attributes objects for the null values instead of null. When the transformer calls getValue() on the Attributes object you get the error.

The fix was to make manifestEntries a Map<String, Object> instead of Map<String, Attributes>.

Issue Links

• duplicates: MSHADE-168 ManifestResourceTransformer manifestEntries map declares wrong generic type