How does the Tomcat container create servlet class instances?

When the container starts , Will read in webapps All the web In application web.xml file , Then on xml File parsing , And read servlet Registration information . then , Register... In each app servlet Classes are loaded , And pass Instantiate the way of reflection .（ Sometimes it's also instantiated on the first request ）

stay servlet Sign up with 1 If it's a positive number , Instantiate at the beginning , If it's not written or negative , The first request for instantiation .