Arrays in Java are considered as ________ data types.
- Primitive
- Object
- Immutable
- Dynamic
Arrays in Java are considered as object data types. Even though they can store elements of primitive data types, arrays themselves are objects in Java. Understanding this distinction is essential for working with arrays and utilizing their various methods and properties.
Which method needs to be overridden to define the task of a thread?
- execute()
- init()
- run()
- start()
To define the task of a thread in Java, you need to override the run() method. This method contains the code that will be executed when the thread is started. The other methods listed are not used for defining the task of a thread.
Using ________ before a variable will restrict its visibility to the same class only.
- package-private (default)
- private
- protected
- public
In Java, when you declare a variable as "private," it restricts its visibility to the same class only. This means that the variable can only be accessed within the class where it is declared and is not accessible from outside classes. It is a crucial concept for data hiding and encapsulation.
What is the use of the consume() method in JavaFX event handling?
- To capture all user input events
- To control the animation timeline
- To create custom JavaFX controls
- To manage and dispatch events to event targets
The EventDispatcher in JavaFX serves the purpose of managing and dispatching events to their respective event targets. It plays a crucial role in event handling within the JavaFX framework, ensuring that events are routed to the correct nodes and event handlers. The other options are not accurate descriptions of the EventDispatcher's role.
The ________ keyword in Java is used to define a variable that cannot be serialized.
- final
- static
- transient
- volatile
In Java, the transient keyword is used to declare a variable that should not be included when an object is serialized. When an object is serialized, its state is converted to a byte stream, and transient variables are excluded from this process.
Consider a scenario where you want to evaluate multiple conditions and execute a block of code when at least one of the conditions is true. Which of the following control structures is the most appropriate?
- do...while loop
- for loop
- if...else if ladder
- while loop
In Java, when you need to evaluate multiple conditions and execute a block of code when at least one condition is true, the most appropriate control structure is the if...else if ladder. This structure allows you to test multiple conditions in sequence and execute the block associated with the first true condition. It's commonly used for handling multiple mutually exclusive cases.
The enhanced for loop (or for-each loop) is also known as the ________ loop.
- Enhanced Loop
- For Loop
- For-Each Loop
- Iteration Loop
The enhanced for loop in Java is often referred to as the "for-each" loop because it iterates through each element of an array or collection, making it a convenient way to loop through elements without explicitly defining an index. Options 1 to 3 are incorrect terms for describing this loop.
______ is an example of an explicit lock in Java.
- CountDownLatch
- ReentrantLock
- Semaphore
- Synchronized
ReentrantLock is an example of an explicit lock in Java. It provides a more flexible and fine-grained way to manage locks compared to the built-in synchronized keyword. It allows for features like reentrant locking and fairness policies, making it suitable for complex synchronization scenarios. The Synchronized keyword is also used for locking, but it is implicit and less flexible. The other options are not examples of explicit locks.
What is the output of the following expression: 7 % 3?
- 0
- 1
- 2
- 3
In Java, the '%' operator is the modulo operator. It calculates the remainder when one number is divided by another. In this case, 7 divided by 3 equals 2 with a remainder of 1. So, the output of the expression 7 % 3 is 1.
How does Java's try-with-resources statement, introduced in Java 7, enhance exception handling?
- It allows you to catch and handle exceptions thrown by resources automatically.
- It allows you to catch multiple exceptions in one catch block.
- It prevents the execution of the finally block.
- It replaces the traditional try-catch block entirely.
Java's try-with-resources statement enhances exception handling by automatically closing resources (e.g., files, streams) after their scope, and if any exceptions are thrown during resource management, they are caught and handled automatically, simplifying resource cleanup.