First of all, thank you so much Alexander for taking the time to explain this so thoroughly.
> > First, am I correct in saying that the default behaviour for a > > Javabean is that each servlet or JSP that uses it will create > a new >instance of that Javabean ? For example, if we have > Register.jsp which >uses a Javabean called memberData.java then > if 2 people were to submit >data to Register.jsp > > at exactly the same time, each page would actually create and use > > a separate instance of the bean memberData.java. Is this correct? > >Nice answer: That depends :-) >a) <jsp:useBean id="mb" class="MyBean" scope="page" /> >The bean is created for exactly this page executed by this user > >b) <jsp:useBean id="mb" class="MyBean" scope="request" /> >The bean is created for this page and all pages you <jsp:include> in this >request. > >c) <jsp:useBean id="mb" class="MyBean" scope="session" /> >The bean is created and accessible by all pages of this application >(You must include this line into all pages) >p.ex.: You create a session bean that accesses a database. The database >connection will be made once and will stand until the session runs out. >There is a seperate bean for every user, though. > >d) <jsp:useBean id="mb" class="MyBean" scope="application" /> >The bean is created the first time a user accesses a page in your >application. From then on, every user and every page will have the same >bean! Lovely concise answer. I've printed this out as a cheat sheet :-) Now, since each JSP is essentially a servlet, how does the servlet perform the sharing of the javabean ? Does a servlet that shares a javabean (similar to the JSP case [d] above, where scope="application"), is actually creating the javabean as a *static* variable so that it is shared by all members of the class ? > > Third, I'm getting confused and starting to doubt my understanding of > > servlets within the Tomcat servlet container. If we have a simple >servlet > > using the helloWorld.class and it just prints "hello world" to > > the web page, > > then if 10 people were to requsest the servlet at the same time, am I > > correct in assuming that 10 different instances of the class are > > created to > > handle these requests ? > >true Great, that's what I thought. But here's why I'm getting confused. The servlet tutorial says that a servlet is created once and once only (that's when the init() is run). http://java.sun.com/docs/books/tutorial/servlets/lifecycle/index.html If the servlet class is created only once, how does Tomcat then create multiple instances of the class ? >I could recommend a german book here, but I think that wouldn't be of >great use for you... Good guess. Learning German through Java would surely be a challenge :) Thank you again, Soefara. _________________________________________________________________ MSN Photos is the easiest way to share and print your photos: http://photos.msn.com/support/worldwide.aspx -- To unsubscribe: <mailto:[EMAIL PROTECTED]> For additional commands: <mailto:[EMAIL PROTECTED]> Troubles with the list: <mailto:[EMAIL PROTECTED]>
