That depends on what your init method does. In any case, the servlet container will call init after it has created an instance of your servlet and before any request is processed - as per the API.
Where do these bizarre questions about servlet methods come from? Is this some sort of on-going joke? Why don't people just read the tutorials and the API documentation? Admitedly, moving from a single-user desktop application environment to a container controlled environment is tricky, but it is all documented.
subject: reaction of the container if we place init() in service()