The collect() method in the Stream API is a type of ________ operation.
- Intermediate
- Stateful
- Stateless
- Terminal
The collect() method is a terminal operation in the Stream API. It is used to accumulate the elements of a stream into a collection, such as a List or Set. Terminal operations are those that trigger the processing of the stream and produce a final result.
In a real-world application managing user profiles, how might parameterized constructors be used to quickly initialize user objects with provided details during registration?
- Parameterized constructors are not used for user profile initialization.
- Parameterized constructors are used for data retrieval from the database.
- Parameterized constructors are used to create admin profiles with elevated privileges.
- Parameterized constructors can accept user details as parameters and create user objects with initialized data during registration.
Parameterized constructors can be utilized in a user profile management system to quickly initialize user objects during the registration process. These constructors accept user details (e.g., username, email, password) as parameters, allowing you to create user objects with pre-populated data, making registration more efficient and straightforward.
Lambda expressions are used primarily to define the implementation of ________ interfaces.
- Abstract
- Functional
- Interface
- Marker
Lambda expressions in Java are primarily used to define the implementation of functional interfaces. A functional interface is an interface that has only one abstract method. Lambda expressions provide a concise way to implement the single abstract method of such interfaces.
Which of the following expressions will result in a value of true?
- "Java" == "java"
- (4 + 6) * 2 == 20
- 10 != 10
- 5 > 3
The expression 5 > 3 is true because 5 is indeed greater than 3. The other options are not true: 10 != 10 is false (since 10 is equal to 10), (4 + 6) * 2 == 20 is true (since 10 equals 20), and "Java" == "java" is false because string comparison in Java is case-sensitive.
Which of the following functional interfaces in Java utilizes Lambda expressions?
- AbstractClass
- FunctionalInterface
- Runnable
- Serializable
The Runnable interface in Java can be implemented using lambda expressions. It's a functional interface with a single abstract method run(). This allows you to use lambda expressions for tasks that can be executed concurrently. Lambda expressions simplify the creation of anonymous classes for such tasks.
What will happen if the superclass method does not exist in the subclass while trying to override it?
- It will automatically create a new method in the subclass with the same name.
- It will lead to a compile-time error.
- It will result in a runtime error.
- It will use the superclass method without any issue.
In Java, when you try to override a method from a superclass in a subclass, the method in the superclass must exist; otherwise, it will lead to a compile-time error. Java enforces method signature matching during compile-time, so if the method doesn't exist in the superclass, the compiler will not find a method to override in the subclass, resulting in an error.
The ________ method of Throwable class can be used to retrieve the description of an exception.
- getDescription()
- getDescriptionText()
- getExceptionDescription()
- getMessage()
The getMessage() method of the Throwable class is used to retrieve the description or message associated with an exception. This message provides additional information about the exception, helping developers understand the cause of the error.
Which of the following classes is used to write characters to a file in Java?
- BufferedReader
- FileOutputStream
- FileWriter
- PrintWriter
The FileWriter class in Java is used to write characters to a file. It provides methods to write character data to a file in a character stream. FileOutputStream is used for writing binary data, PrintWriter is used for formatted text output, and BufferedReader is used for reading character data, not writing.
Which method is typically overridden to handle an event in JavaFX?
- handle()
- handleEvent()
- init()
- start()
In JavaFX, to handle an event, you typically override the handle() method. This method is part of the EventHandler interface, and you provide your custom event-handling logic within it. The other options, such as start(), are methods used for different purposes in JavaFX applications.
In which scenario would you choose an abstract class over an interface?
- When you want to achieve complete abstraction and hide the implementation details of a class.
- When you want to define constants and static methods that are common to a group of related classes.
- When you want to ensure multiple inheritance of behavior without worrying about method implementation conflicts.
- When you want to provide a common base class with some shared functionality and allow derived classes to implement additional methods.
You would choose an abstract class over an interface when you want to provide a common base class with some shared functionality and allow derived classes to implement additional methods. Abstract classes can have both abstract and concrete methods, making them suitable for situations where you need to provide a common structure along with partial implementation.