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.
How can you read an 8-bit byte from a file using byte streams in Java?
- BufferedReader
- FileReader
- FileReader
- InputStream
To read an 8-bit byte from a file using byte streams in Java, you should use the InputStream class. Byte streams are designed to work with binary data, and InputStream is the parent class for all byte input streams. FileReader and BufferedReader are used for character-based reading, not for reading raw bytes.
Which data type would be suitable to store a character value in Java?
- byte
- char
- double
- float
In Java, the char data type is used to store a single character. It can hold any character, including letters, numbers, and special symbols.
Consider a scenario where an application retrieves a large amount of data from a database and displays it in a UI paginated form. How would you efficiently manage and optimize data retrieval and display using JDBC?
- Implementing client-side caching of database results to improve data retrieval speed for pagination.
- Loading all data into memory and applying pagination through custom code to limit the data displayed in the UI.
- Retrieving all data at once and performing pagination on the client side using Java collections.
- Using JDBC ResultSet's pagination features, like setFetchSize, to fetch data in smaller chunks from the database.
When dealing with large data sets, it's essential to retrieve and display data efficiently. JDBC provides features like setFetchSize to fetch data in smaller portions, reducing memory usage and improving performance. Retrieving all data at once can lead to memory issues. Client-side caching can help, but it may not be suitable for very large datasets. Understanding these JDBC features is crucial for optimization.
Which method is used to check if there are more lines of text to read from a BufferedReader object?
- canReadMore()
- hasMoreLines()
- hasNext()
- hasNextLine()
The BufferedReader class has a method called hasNextLine() that is used to check if there are more lines of text to read from the BufferedReader object. It returns true if there are more lines and false if the end of the file has been reached. The other options do not represent the correct method for this purpose.
Which of the following character stream classes should be used to read characters, arrays, and lines efficiently?
- BufferedReader
- CharArrayReader
- FileReader
- InputStreamReader
The BufferedReader class is used to read characters, arrays, and lines efficiently from a character input stream. It provides buffering, which makes reading more efficient. FileReader is used to read characters from files, and InputStreamReader is used for byte-to-character conversion. CharArrayReader is used to read from character arrays.
When using a single-thread executor, what happens if a submitted task throws an exception?
- The exception is caught, logged, and the executor continues to execute other tasks.
- The exception is ignored, and the executor continues to execute other tasks.
- The exception is propagated up the call stack to the caller of the submit() method.
- The thread running the task is terminated, and the executor replaces it with a new thread.
In a single-thread executor, when a submitted task throws an exception, it is caught and logged, but the executor continues to execute other tasks. The executor does not terminate due to an exception in a single task; it maintains the single thread for execution.