How is method overloading resolved when there is an ambiguity in method signatures?
- The JVM randomly selects one of the overloaded methods.
- The compiler throws an error and asks for explicit casting of parameters.
- The method with the least specific parameter types is chosen.
- The method with the most specific parameter types is chosen.
In Java, when there is an ambiguity in method signatures during method overloading, the compiler chooses the method with the most specific parameter types. Specificity is determined by the inheritance hierarchy, with the most specific type being favored. This ensures that the correct method is called based on the arguments provided.
The method ________ is used to return the hash code value for a Map.
- getHashcode()
- hashCode()
- hashValue()
- mapHash()
In Java, the hashCode() method is used to return the hash code value for an object. In the context of a Map, this method is often used to calculate the hash code for keys, which is crucial for efficient storage and retrieval in hash-based data structures like HashMap and Hashtable. The other options are not standard methods for obtaining hash codes.
What keyword is used to extend a class in Java?
- extends
- implements
- inherits
- subclass
In Java, the extends keyword is used to indicate inheritance and extend a class. When a class extends another class, it inherits all the members (fields and methods) of the parent class, allowing you to create a subclass that inherits and extends the functionality of the superclass.
The ScheduledExecutorService interface extends ________ and provides methods to schedule commands to run after a given delay or to execute periodically.
- Callable
- ExecutorService
- Future
- Runnable
The ScheduledExecutorService interface extends the ExecutorService interface in Java. It provides additional methods for scheduling tasks to run after a specified delay or at regular intervals. This is a useful feature for implementing scheduled tasks or background jobs in applications.
If a class implements two interfaces with default methods having the same signature, the compiler will throw an error unless the class ________ the conflicting method.
- abstracts
- hides
- overrides
- renames
In Java, if a class implements two interfaces with default methods having the same signature, it must provide an implementation for the conflicting method by using the @Override annotation to explicitly indicate that it is intended to override the method. This resolves the conflict and prevents a compilation error. Renaming, hiding, or making it abstract won't resolve the issue.
What are the challenges of implementing operator overloading in Java?
- Java does not support operator overloading, so there are no challenges to address.
- The challenge is defining custom operators, which may not be intuitive to developers familiar with Java's standard operators.
- The challenge is the risk of causing performance issues due to overloaded operators.
- The main challenge is ambiguity, as overloading operators can lead to confusion and unintended behavior.
The main challenge of implementing operator overloading in Java is ambiguity. Operator overloading can lead to confusion and unintended behavior, making the code less readable and maintainable. Since Java doesn't support operator overloading for user-defined classes, developers are encouraged to use meaningful method names instead.
Which sorting algorithm uses a divide-and-conquer strategy to sort data?
- Bubble Sort
- Insertion Sort
- Merge Sort
- Selection Sort
Merge Sort is a sorting algorithm that uses a divide-and-conquer strategy. It divides the unsorted list into smaller sublists, sorts those sublists, and then merges them to obtain the final sorted list. This approach results in better performance compared to some other sorting algorithms.
You're developing a game using JavaFX where players interact with multiple animated objects on the screen. How would you efficiently manage and handle multiple events generated by user interactions without causing performance issues?
- Attach event listeners to each individual object to ensure specific actions are taken for each object's interactions.
- Increase the frame rate to ensure that events are processed faster, thus avoiding performance issues.
- Use a single event handler for all objects and manually check which object triggered the event.
- Use event delegation to handle events at a higher-level parent node, reducing the number of event listeners attached to individual objects.
In JavaFX, managing multiple events efficiently is crucial for performance. Using event delegation by handling events at a higher-level parent node minimizes the number of event listeners, reducing overhead. This is a common best practice in JavaFX game development. Increasing the frame rate alone won't solve performance issues and may lead to excessive resource consumption. Using a single event handler is less efficient than event delegation, and attaching listeners to each object increases overhead.
Which of the following loops will always execute its code block at least once?
- do-while loop
- for loop
- if statement
- while loop
The do-while loop is designed to execute its code block at least once, as it checks the condition after executing the loop body. This is useful when you want to ensure that a piece of code runs before checking the condition for termination.
The method ________ of FileOutputStream class is used to write a specific byte of data to a file output stream.
- append
- write
- writeByte
- writeData
The write method of the FileOutputStream class is used to write a specific byte of data to a file output stream. You can use this method to write individual bytes or byte arrays to a file.