Configuration entity classes. All objects ending in "Config" are immutable and must be constructed using their inner "Builder" class. For example, a PackageConfig object can be created via:

        PackageConfig config = new PackageConfig.Builder("myPackage").build();

The methods on the builder object are chainable to support constructions like this:

        ResultConfig config = new ResultConfig.Builder("success", "myapp.MyResult")
            .addParam("location", "/foo.jsp")
            .build();