我的jsp代码只有当我在Tomcat lib中保留jars而不是类路径中的lib folde时才有效

In my application I am calling a bean from JSP and displaying data.I have kept all required jars in lib folder and that is in build path.When I run this bean it fetches the data successfully. But when I call this bean in JSP it says No Class defination.I found a workaround for this that is putting all the jars also in the lib folder of Tomcat.(apart from keeping in classpath). Means now i have to deploy the war and also put jars in tomcat lib.but why do i have to do this when jars are already in classpath.In my application I am calling a bean from JSP