A servlet receives form data with both text and file inputs. Identify the correct approach to parse this data.
- Convert the data to JSON and parse it
- Parse the data manually using String methods
- Use a library like Apache Commons FileUpload
- Use the built-in Java Scanner class
The correct approach is to use a library like Apache Commons FileUpload, which is designed to handle form data with both text and file inputs efficiently and reliably.
In a servlet, how can you determine if a request parameter has multiple values?
- request.getMultipleValues(parameterName)
- request.getParameterValues(parameterName)
- request.hasMultipleValues(parameterName)
- request.isMultiValued(parameterName)
To determine if a request parameter has multiple values, you can use request.getParameterValues(parameterName), which returns an array of values associated with the given parameter name.
In a servlet, how can you retrieve parameters sent via the POST method?
- request.getParameter()
- request.getParameters()
- request.getPostParameters()
- request.retrievePostParams()
Parameters sent via the POST method in a servlet can be retrieved using the request.getParameter() method.
If a client application needs to request a large amount of data without affecting the server's state, which method should it use and why?
- DELETE, because it is a safe method for retrieving data.
- GET, because it is idempotent and does not modify the server's state.
- POST, because it supports larger data payloads than GET.
- PUT, because it is specifically designed for requesting large data sets.
The GET method is idempotent and does not modify the server's state, making it suitable for requesting large amounts of data without side effects. POST, although supporting larger payloads, is not intended for safe, idempotent operations.
When a servlet encounters an error during initialization, which method gets invoked next?
- destroy()
- doError()
- initError()
- service()
If a servlet encounters an error during initialization, the initError() method is invoked next to handle the initialization error.
What is the significance of the Last-Modified header in HTTP servlet responses?
- It controls the cache behavior for the servlet response.
- It indicates the last modification time of the servlet.
- It signals the client to request the servlet again.
- It specifies the expiration time of the servlet.
The Last-Modified header informs the client about the last modification time of the servlet, allowing the client to cache the response and avoid unnecessary requests if the content hasn't changed.
The _________ attribute specifies the subset of URLs to which a cookie will be sent.
- Domain
- Expires
- Path
- Secure
The Domain attribute specifies the subset of URLs to which a cookie will be sent.
The method __________ is used when the servlet needs to redirect the client to a different domain.
- forwardResponse
- redirectToDomain
- sendForward
- sendRedirect
The method sendRedirect is used when the servlet needs to redirect the client to a different domain.
How does the servlet differ from JSP in terms of performance optimization?
- Both have similar performance
- JSPs are typically faster
- Performance depends on the specific use case
- Servlets are typically faster
Servlets are generally considered faster than JSPs as they involve less overhead. JSPs, being text-based, may have a slight performance cost due to the need for parsing and translation into servlets during the initial request.
To send a large amount of data in a request, the _______ method is preferred.
- DELETE
- GET
- POST
- PUT
To send a large amount of data in a request, the POST method is preferred as it allows for sending data in the request body.