42 Lecture
CS506
Midterm & Final Term Short Notes
Expression Language
Expression Language (EL) is a scripting language used in web development to embed dynamic content within templates. It simplifies data retrieval, manipulation, and display, enhancing interactions between web pages and server-side code, often see
Important Mcq's
Midterm & Finalterm Prepration
Past papers included
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Certainly, here are 10 multiple-choice questions related to Expression Language (EL), along with their solutions and multiple options:
**Question 1: What is the primary purpose of Expression Language (EL) in web development?**
A) Styling web pages.
B) Managing server-side logic.
C) Embedding dynamic content in templates.
D) Optimizing database queries.
**Solution: C) Embedding dynamic content in templates.**
**Question 2: Which technology commonly uses Expression Language for dynamic content in Java web applications?**
A) JavaBeans.
B) Java Applets.
C) JavaFX.
D) Java Threads.
**Solution: A) JavaBeans.**
**Question 3: In EL, which symbol is used to access properties or attributes of Java objects?**
A) @
B) #
C) $
D) .
**Solution: D) .**
**Question 4: What is the result of the EL expression "${5 + 3}"?**
A) 53
B) 8
C) "${5 + 3}"
D) 35
**Solution: B) 8.**
**Question 5: Which EL expression is used to retrieve the value of a JavaBean property "name"?**
A) ${name}
B) #{name}
C) ${bean.name}
D) #{bean.name}
**Solution: C) ${bean.name}.**
**Question 6: What does the EL expression "${empty list}" evaluate to, assuming "list" is an empty list?**
A) true
B) false
C) null
D) "${empty list}"
**Solution: A) true.**
**Question 7: In EL, how do you call a method on a Java object?**
A) ${object.method()}
B) ${object.method}
C) ${object.method{}}
D) ${method.object}
**Solution: A) ${object.method()}.**
**Question 8: What is the purpose of the "${param}" implicit object in EL?**
A) Accessing request parameters.
B) Accessing session attributes.
C) Performing mathematical calculations.
D) Evaluating expressions.
**Solution: A) Accessing request parameters.**
**Question 9: Which EL operator is used for the "not equal" comparison?**
A) ==
B) !=
C) <>
D) ><
**Solution: B) !=.**
**Question 10: What is the outcome of the EL expression "${10 > 5 && 3 < 2}"?**
A) true
B) false
C) "${10 > 5 && 3 < 2}"
D) error
**Solution: B) false.**
Subjective Short Notes
Midterm & Finalterm Prepration
Past papers included
Download PDF
Certainly, here are 10 short-answer questions related to Expression Language (EL), along with their answers:
**Question 1: What is Expression Language (EL) used for in web development?**
**Answer:** Expression Language (EL) is used to embed dynamic content and evaluate expressions within web templates, allowing for easy manipulation and display of data from server-side code.
**Question 2: How is an EL expression typically enclosed?**
**Answer:** An EL expression is typically enclosed within curly braces, like this: "${expression}".
**Question 3: What kind of content can be included in an EL expression?**
**Answer:** EL expressions can include variables, properties, method calls, arithmetic operations, and logical expressions.
**Question 4: How do you access a property of a Java object using EL?**
**Answer:** To access a property of a Java object using EL, you use the dot notation, like this: ${object.property}.
**Question 5: What is the purpose of the "empty" keyword in EL?**
**Answer:** The "empty" keyword in EL is used to check if a value is null or empty, like "${empty variable}".
**Question 6: How do you iterate over a collection using EL?**
**Answer:** You can use the "forEach" loop construct in EL to iterate over a collection, like this: "${collectionVar.forEach(item -> ...)}".
**Question 7: What is the difference between ${} and #{} syntax in EL?**
**Answer:** The "${}" syntax is used for immediate evaluation, while "#{}" syntax is used for deferred evaluation in some contexts, like in JSF.
**Question 8: What does the implicit object "${param}" represent in EL?**
**Answer:** The implicit object "${param}" represents a request parameter value and is used to access parameter values submitted with an HTTP request.
**Question 9: How is a method call performed using EL?**
**Answer:** A method call on a Java object is performed using the dot notation, like this: ${object.method()}.
**Question 10: What is the benefit of using EL in web applications?**
**Answer:** EL simplifies the integration of dynamic data into web templates, promoting cleaner and more readable code. It also enhances the separation of concerns by keeping the presentation layer focused on display logic.