in your program that service method is just like normal method.that method does't contain any parameters and does't throws any exception. so that is just like normal method. bydefault that method won't executes,and you have to call explacitly.
if you wrote the service method as follows then it may executes bydefault.
the service method you have written is an ordinary method and wont be called by the servlet container.
it is as if you have given a return type to constructor and hoping it to execute when you follow an object creation process.
Now Moving for SCWCD and then for OCA & OCP