ServletConfig vs ServletContext

Question

What is the difference between ServletConfig and ServletContext interface?

Answer 1

The ServletConfig parameters are specified for a particular servlet and are unknown to other servlets. It is used for intializing purposes.

The ServletContext parameters are specified for an entire application outside of any particular servlet and are available to all the servlets within that application. It is application scoped and thus globally accessible across the pages.

Answer 2

Source : Difference between ServletConfig and ServletContext in Java

ServletConfig

• ServletConfig available in javax.servlet.*; package

• ServletConfig object is one per servlet class

• Object of ServletConfig will be created during initialization process of the servlet

• This Config object is public to a particular servlet only

• Scope: As long as a servlet is executing, ServletConfig object will be available, it will be destroyed once the servlet execution is completed.

• We should give request explicitly, in order to create ServletConfig object for the first time

• In web.xml – <init-param> tag will be appear under <servlet-class> tag

Here's how it looks under web.xml : (Source)

<servlet>     <servlet-name>ServletConfigTest</servlet-name>     <servlet-class>com.stackoverflow.ServletConfigTest</servlet-class>     <init-param>         <param-name>topic</param-name>         <param-value>Difference between ServletConfig and ServletContext</param-value>     </init-param> </servlet> 

ServletContext

• ServletContext available in javax.servlet.*; package

• ServletContext object is global to entire web application

• Object of ServletContext will be created at the time of web application deployment

• Scope: As long as web application is executing, ServletContext object will be available, and it will be destroyed once the application is removed from the server.

• ServletContext object will be available even before giving the first request In web.xml – <context-param> tag will be appear under <web-app> tag

Here's how it looks under web.xml :

<context-param>     <param-name>globalVariable</param-name>     <param-value>com.stackoverflow</param-value> </context-param> 

So finally…….

No. of web applications = That many number of ServletContext objects [ 1 per web application ]
No. of servlet classes = That many number of ServletConfig objects

Difference between ServletContext and ServletConfig in Servlets JSP in tabular format(Source)