Before you try to use the CASValidateFilter, consider whether the basic CASFilter would better suit your needs. CASFilter provides a standard distribution of the most frequently needed CASification behaviors for Java webapps.
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In this case, the filter will perform ticket validation on the URL /webapp/Login if a service ticket is present. Unlike CASFilter, CASValidateFilter will just let the request right through without performing any CAS authentcation if a service ticket is not presented on the request.
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