What is the first method called in the lifecycle of a servlet?
- destroy()
- doGet()
- init()
- service()
The init() method is called when a servlet is first loaded into memory and is used for initialization purposes.
How can filters modify the request and response objects in a filter chain?
- Modify only the request object
- Modify the objects directly
- Use the doFilter() method
- Use the init() method
Filters can modify the request and response objects by using the doFilter() method in the filter chain.
The __________ method is called by the web container to indicate that a filter is being taken out of service.
- destroy()
- dispose()
- remove()
- unregister()
The destroy() method is called by the web container to indicate that a filter is being taken out of service.
The __________ object provides the filter with information about its initialization parameters.
- FilterConfig
- FilterContext
- InitParams
- ServletContext
The FilterConfig object provides the filter with information about its initialization parameters, allowing the filter to retrieve its configuration.
Filters can be used to manipulate the __________ and __________ before they reach a servlet or JSP.
- context, attributes
- headers, body
- request, response
- session, cookie
Filters can manipulate the request and response objects before they reach a servlet or JSP, allowing for various pre-processing tasks.
To apply multiple filters to a single resource, the web.xml file must define a __________ for each filter.
- filter-chain
- filter-group
- filter-list
- filter-mapping
In the web.xml file, a filter-mapping element must be defined for each filter to apply multiple filters to a single resource.
Consider a scenario where a request needs to be authenticated and then logged. How should the filters be arranged in the filter chain?
- Authenticate, Log, Other Filters, Process Request
- Authenticate, Other Filters, Log, Process Request
- Log, Authenticate, Other Filters, Process Request
- Other Filters, Authenticate, Log, Process Request
In this scenario, it is ideal to perform authentication before logging. Therefore, the correct order is to place the authentication filter before the logging filter in the filter chain. This ensures that the request is authenticated first, and then the logging is done.
In a scenario where a filter chain is used for both compression and encryption, which process should ideally occur first?
- Compression, Encryption, Other Filters, Process Request
- Compression, Other Filters, Encryption, Process Request
- Encryption, Compression, Other Filters, Process Request
- Other Filters, Compression, Encryption, Process Request
In this scenario, it is generally recommended to perform encryption before compression. This ensures that the data is first secured through encryption and then compressed. Therefore, the correct order is to place the encryption filter before the compression filter in the filter chain.
When a request is processed through multiple filters, how is the order of execution determined in a servlet application?
- The order is determined alphabetically based on filter names.
- The order is determined by the order in the web.xml file.
- The order is determined by the order in which filters are added programmatically in the servlet code.
- The order is determined randomly at runtime.
The order of execution of filters is determined by the order in which they are declared in the deployment descriptor (web.xml) file. The filters are applied to the request and response objects in the order specified in the deployment descriptor.
Which listener interface in Servlets is used for receiving notification about ServletContext lifecycle changes?
- HttpSessionListener
- ServletContextAttributeListener
- ServletContextListener
- ServletRequestListener
The ServletContextListener interface is used for receiving notifications about ServletContext lifecycle changes, such as when it is initialized or destroyed.