exception

javax.servlet.ServletException: Cannot open connection
org.vraptor.VRaptorServlet.service(VRaptorServlet.java:82)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:81)

root cause

org.hibernate.exception.GenericJDBCException: Cannot open connection
org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:420)
org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:144)
org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:119)
org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:57)
org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1326)
br.com.caelum.vraptor.dao.ProdutoDao.adiciona(ProdutoDao.java:19)
br.com.caelum.vraptor.logic.ProdutoLogic.adiciona(ProdutoLogic.java:13)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:585)
org.vraptor.reflection.ReflectionUtil.invoke(ReflectionUtil.java:84)
org.vraptor.reflection.JavaMethod.invoke(JavaMethod.java:31)
org.vraptor.component.DefaultLogicMethod.execute(DefaultLogicMethod.java:123)
org.vraptor.interceptor.ExecuteLogicInterceptor.intercept(ExecuteLogicInterceptor.java:37)
org.vraptor.core.InterceptorsLogicFlow.execute(InterceptorsLogicFlow.java:82)
org.vraptor.interceptor.SettingAndValidationInterceptor.intercept(SettingAndValidationInterceptor.java:141)
org.vraptor.core.InterceptorsLogicFlow.execute(InterceptorsLogicFlow.java:82)
org.vraptor.interceptor.InjectionInterceptor.intercept(InjectionInterceptor.java:45)
org.vraptor.core.InterceptorsLogicFlow.execute(InterceptorsLogicFlow.java:82)
org.vraptor.interceptor.ComponentLookupInterceptor.intercept(ComponentLookupInterceptor.java:56)
org.vraptor.core.InterceptorsLogicFlow.execute(InterceptorsLogicFlow.java:82)
org.vraptor.interceptor.RegisterAttributesInteceptor.intercept(RegisterAttributesInteceptor.java:57)
org.vraptor.core.InterceptorsLogicFlow.execute(InterceptorsLogicFlow.java:82)
org.vraptor.core.VRaptorExecution.execute(VRaptorExecution.java:91)
org.vraptor.core.VRaptorController.execute(VRaptorController.java:39)
org.vraptor.VRaptorServlet.service(VRaptorServlet.java:57)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:81)