No Errors in Aggregate Graph but in Tomcat

Dear All . Greetings , I just run a simple test plan which has a Login page load and an ajax.do . I have run this test plan with 500 Concurrent users . I didn't get any error ( Error % ) in Aggregate graph , But while monitoring the tomcat server , I got the following error few times

Re: No Errors in Aggregate Graph but in Tomcat

Most likely your applications returned pages with HTTP 200 (OK) as a return code and not HTTP 500 (Internal Server Error) or something similar. If you don't add any additional assertions (positive or negative), JMeter will interpret HTTP 200 as a correct result. There is no intelligence in