我正在关注免费的在线书籍“Grails 入门”( http://www.infoq.com/minibooks/grails-getting-started )，并且在尝试列出任何域类时遇到 java.lang.ClassCastException。谁能破译这个？
URI: /RaceTrack/runner/list
Class: java.lang.ClassCastException
Message: sun.proxy.$Proxy26 cannot be cast to org.springframework.orm.hibernate3.HibernateCallback
堆栈跟踪：
Line | Method
->> 15 | list in RunnerController.groovy
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| 186 | doFilter in PageFragmentCachingFilter.java
| 63 | doFilter in AbstractFilter.java
| 1145 | runWorker in java.util.concurrent.ThreadPoolExecutor
| 615 | run . . . in java.util.concurrent.ThreadPoolExecutor$Worker
^ 722 | run in java.lang.Thread
附加信息（PageFragmentCachingFilter.java 的第 186 行附近）
183: if(method == null) {
184: log.debug("No cacheable method found for {}:{} {}",
185: new Object[] { request.getMethod(), request.getRequestURI(), getContext() });
186: chain.doFilter(request, response);
187: return;
188: }
189: Collection<CacheOperation> cacheOperations = cacheOperationSource.getCacheOperations(
附加信息（在 AbstractFilter.java 的第 63 行附近）：
60: try {
61: // NO_FILTER set for RequestDispatcher forwards to avoid double gzipping
62: if (filterNotDisabled(request)) {
63: doFilter(request, response, chain);
64: }
65: else {
66: chain.doFilter(req, res);