RichFaces4 startup fails with java.lang.IllegalArgumentException: duplicate key: class javax.faces.convert.DoubleConverter

Question

This seems not be not a simple task with RichFaces4 without Maven, I download myfaces-2.0.9 jars and richfaces 4.0.0 and added sac-1.3.jar, guava-r08.jar and cssparser-0.9.5

Answer 1

This can happen if you also include the RichFaces source code JAR files in the classpath. They do not belong in the webapp's runtime classpath. It are the ones with a filename ending in -source.jar. You should remove them from the /WEB-INF/lib and put them if necessary somewhere else which do not end up in the webapp's runtime classpath.

The culprit is the csv.xml file which is present in /META-INF folder of both the richfaces-components-ui-4.0.0.Final.jar and richfaces-components-ui-4.0.0.Final-source.jar files. That file definies the standard converters and validators. However, because that file now appears twice in the classpath, it's been read twice, resulting in this duplicate key exception.

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Unrelated to the concrete problem, removing Tomahawk because you're using MyFaces is a non-argument. The MyFaces JSF implementation does not contain the same components as Tomahawk. It's just another JSF implementation and technically the competitor of Mojarra. Tomahawk is a standalone component library which offers more enhanced components on top of the standard JSF implementation and can be used as good on top of every JSF implementation.