Envisage a situation where you are developing a high-throughput application where multiple threads are reading and writing to a data structure. Which collection would you select to store data and why?
- ArrayList
- ConcurrentHashMap
- HashSet
- LinkedList
In this scenario, a ConcurrentHashMap is the preferred choice. It's designed for concurrent access by multiple threads, making it suitable for high-throughput applications. Unlike ArrayList, LinkedList, and HashSet, it provides thread-safety without sacrificing performance. It achieves this through a mechanism that allows multiple threads to read concurrently while providing efficient locking for write operations.
How can you prevent the fall-through behavior in a switch case?
- Fall-through behavior cannot be prevented in a switch case.
- Use the break statement after each case block.
- Use the continue statement after each case block.
- Use the stop statement after each case block.
In Java, you can prevent fall-through behavior in a switch case by using the break statement at the end of each case block. When a break is encountered, the control flow exits the switch statement, preventing the execution of subsequent cases. Without break, fall-through behavior will occur, and all cases after the matched one will be executed.
A ______ event is an event that JavaFX propagates up the scene graph from child to parent.
- Bubbling
- Capturing
- Focusing
- Mouse
In JavaFX, a "bubbling" event refers to an event that starts from the source (usually a node) and propagates up the scene graph hierarchy from child to parent nodes. This allows parent nodes to react to events triggered by their children. The other options are not related to event propagation.
How does thread priority impact the order in which threads are executed?
- Thread priority has no impact on the order of thread execution.
- Thread priority is randomly assigned, so there is no fixed order.
- Threads with higher priority are always executed before threads with lower priority.
- Threads with lower priority are always executed before threads with higher priority.
Thread priority in Java can be set using the setPriority() method and can range from 1 to 10, where 1 is the lowest and 10 is the highest priority. Threads with higher priority are given preference, but it's not guaranteed that they will always execute first, as it depends on the thread scheduler and other factors.
Why might a programmer choose to use package-private (default) access level over private for a method within a class?
- Package-private methods allow access to subclasses, promoting code reusability within the same package.
- Package-private methods are accessible from outside the class, making them more versatile.
- Package-private methods are more restrictive than private methods and provide better encapsulation.
- Private methods cannot be used within a class.
Programmers might choose package-private access level for a method when they want to allow subclasses to access the method for code reuse but restrict access from outside the package. It strikes a balance between encapsulation and reusability, making it a useful choice in certain situations.
In Java, the ______ operator is used to increment a variable's value by 1.
- *
- ++
- --
- /
In Java, the "++" operator is used to increment a variable's value by 1. For example, "int x = 5; x++; // x is now 6". The other options do not perform this specific operation.
Which class would you use for reading binary data from a file?
- BinaryReader
- BufferedReader
- FileInputStream
- FileReader
To read binary data from a file in Java, you should use the FileInputStream class. It's designed for reading raw binary data and doesn't interpret the data as characters. Other options, like FileReader and BufferedReader, are meant for reading text data and may not handle binary data correctly.
What is the purpose of using getters and setters in Java?
- To access and modify the private attributes
- To create objects
- To declare variables
- To perform mathematical operations
Getters and setters are used to access and modify the private attributes (variables) of a class. They help in achieving encapsulation by providing controlled access to the class's internal state. Getters allow reading the value, and setters allow modifying it while enforcing rules and validation.
Which method is used to properly stop a JavaFX application?
- Application.stop();
- Platform.exit();
- System.exit(0);
- stage.close();
To properly stop a JavaFX application, the Application.stop() method should be used. This method is automatically called when the JavaFX application is exiting. It provides a clean way to release resources, close windows, and perform any necessary cleanup operations before the application terminates. Using System.exit(0) or closing the stage directly may not handle cleanup tasks properly.
The InetAddress class provides methods to get the IP address of a local computer by using method ________.
- getHostAddress()
- getIPAddress()
- getLocalAddress()
- getLocalHost()
In Java, you can obtain the IP address of the local computer using the getLocalHost() method of the InetAddress class. It returns an InetAddress object representing the local host's IP address. The other options are not used for this purpose.