Which method is responsible for cleaning up resources held by a filter in the filter chain?
- cleanUp()
- cleanupResources()
- destroy()
- releaseResources()
The destroy() method is responsible for cleaning up resources held by a filter in the filter chain.
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.
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.
Which method is used to initialize a filter in the filter chain?
- init()
- initFilter()
- initialize()
- initializeFilter()
The init() method is used to initialize a filter in the filter chain. This method is called by the servlet container when the filter is first created.
How does a filter pass the request and response to the next entity in the filter chain?
- Automatically passed by the servlet container
- By directly calling the next filter
- By setting a flag in the request
- Using the chain.doFilter() method
A filter passes the request and response to the next entity in the filter chain using the chain.doFilter() method, which allows the request and response to move to the next filter or servlet in the chain.
What is the primary purpose of a filter chain in a servlet environment?
- To establish a secure connection
- To execute servlets sequentially
- To handle exceptions in a servlet
- To perform multiple filters on a request and response
The primary purpose of a filter chain is to allow multiple filters to be applied to a request and response in a sequential order, enabling the execution of various processing tasks.
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.
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.
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.
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.
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.
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.