When the project started again, reported a baffling mistake: nested exception is java.lang.Error: Unresolved compilation problems, then there would be no part of the class compiles successfully, although it can, but there is definitely a problem, this problem is very unexpected, because before this is no problem, then I checked online, a lot of that is compiled with jdk version of the problem, since other projects recently because indeed replaced jdk version, so I carefully checked again determine my jdk version is correct. But the problem is still not resolved, I will my local some changes and restore, clean, or not, I get hurt. Then because the project still up, I tried to get him alone, do first task, like a slow slow to engage in him, and I changed a page later, there is no automatic hot deployment, restart the project does not work, clean no, I carefully checked code to determine the future I write no problem, this time to consider the tomcat was compiled in the project there is a problem, it causes the compiler is not passed. Then I will be following tomcat webapps and work / Catalina / localhost following files emptied. Then redeploy compiled. This time the result is very smooth up, there is no report that somehow wrong, I also made changes to the entry into force of the page.
Although the problem is resolved, but the cause of the problem I do not know, tomcat compiled Why go wrong, it remains to be studied. My guess is the reason for the replacement jdk, but when I started this project jdk is in return, so not sure the reason. Another point is myeclipse not completely recompiled after clean it really is a pit, later to pay attention.