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The process of converting a primitive data type to a wrapper class object in Java is known as ________.

  • Autoboxing
  • Casting
  • Parsing
  • Unboxing
The process of converting a primitive data type to a wrapper class object in Java is known as "Autoboxing." Autoboxing is the automatic conversion of primitive data types to their corresponding wrapper classes. For example, converting an int to an Integer.
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When a class implements Serializable, it should have a static final field named ______.

  • classVersion
  • serialVersion
  • serialVersionUID
  • versionID
When a class implements the Serializable interface, it's recommended to have a static final long serialVersionUID field. This field helps ensure that the serialized and deserialized versions of the class are compatible. It's used to verify that the class being deserialized is compatible with the one that was originally serialized. The other options are not standard.
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How can you configure the thread names of an ExecutorService for debugging and identification purposes?

  • Thread names are automatically derived from the name of the task submitted to the ExecutorService.
  • You can change thread names by calling the setName method on the ExecutorService instance after it's created.
  • You can set the thread names when creating a new thread pool using the ThreadFactory interface and providing a custom ThreadFactory implementation.
  • You cannot configure thread names for threads in an ExecutorService; they are automatically generated by Java.
To configure thread names of an ExecutorService for debugging and identification purposes, you can provide a custom ThreadFactory implementation when creating the thread pool. This allows you to set meaningful names for the threads, making it easier to identify their purpose in logs and debugging. Thread names are not automatically configurable and are typically based on the default naming conventions unless you specify otherwise.
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What is the major drawback of Linear Search compared to other searching algorithms?

  • Linear Search has a high time complexity.
  • Linear Search is not easily implemented.
  • Linear Search is not suitable for sorted data.
  • Linear Search requires extra memory.
The major drawback of Linear Search is that it is not efficient for searching in large sets of sorted data. Unlike Binary Search or Hashing, which have logarithmic time complexity, Linear Search has a linear time complexity, making it slower for large datasets. It doesn't take advantage of data being sorted. The other options do not accurately represent the primary drawback of Linear Search.
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Imagine that you are building a Java application to download files from an FTP server. How would you establish a connection and ensure the secure transmission of files from the server to your application?

  • Employ the java.util.zip.ZipOutputStream and java.util.zip.ZipInputStream classes to compress and decompress files during transfer. Implement secure transmission using encryption libraries.
  • Establish a connection using the java.io.BufferedReader and java.io.BufferedWriter classes. Ensure secure transmission through custom encryption and decryption logic.
  • Establish an FTP connection using the org.apache.commons.net.ftp.FTPClient class, and enable FTPS (FTP over SSL/TLS) for secure file transfer.
  • Use the java.net.Socket class to create a socket connection and implement custom encryption for secure transmission.
To establish a secure connection for downloading files from an FTP server in Java, you can use the org.apache.commons.net.ftp.FTPClient class. To ensure secure transmission, enable FTPS (FTP over SSL/TLS) in your FTP client configuration. This approach ensures that file transfers between your application and the FTP server are encrypted and secure.
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Consider building a microservice handling requests from various clients and other microservices. How would you implement socket programming for non-blocking, asynchronous I/O and high throughput?

  • Use Java's AsynchronousSocketChannel with NIO for asynchronous I/O and high throughput.
  • Implement a multi-threaded server using Java's ServerSocket with one thread per connection.
  • Employ Java's Socket with multi-threading for parallel request processing.
  • Use Java's DatagramSocket with UDP for low overhead and high throughput.
To achieve non-blocking, asynchronous I/O, and high throughput in a microservice, Java's AsynchronousSocketChannel with NIO (Option 1) is the ideal choice. It allows for efficient handling of multiple connections without the need for a thread per connection, leading to scalability. Options 2 and 3, which use multi-threading, may lead to higher resource consumption and less scalability. Option 4, utilizing UDP with DatagramSocket, may not guarantee reliable, ordered, and synchronous communication, which is essential for a microservice handling requests.
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Consider a scenario where a superclass method that throws an exception is overridden in the subclass. How should the exception handling be approached in this case, ensuring that the application's robustness is maintained?

  • The subclass should rethrow the exception using throw to propagate it upward.
  • The subclass should catch and handle the exception, ensuring that it doesn't break the application.
  • The subclass should ignore the exception and not include any exception handling code.
  • The subclass should modify the method signature to remove the exception declaration.
In this scenario, when a subclass overrides a superclass method that throws an exception, it should generally follow option 1. This means rethrowing the exception using throw to propagate it upward in the call stack. This approach maintains robustness by allowing higher-level code to handle the exception appropriately. Options 2 and 3 may lead to suppressed exceptions and unexpected behavior. Option 4 is incorrect as it doesn't handle the exception.
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In which phase of the Merge Sort algorithm is the majority of the processing work done?

  • Conquer Phase
  • Divide Phase
  • Initialization Phase
  • Merge Phase
In the Merge Sort algorithm, the majority of the processing work is done during the Merge Phase. This is where the sorted sublists are combined (merged) to form larger sorted sublists. The Divide Phase splits the original list into smaller sublists, and the Conquer Phase recursively sorts those sublists, but the Merge Phase is where the sorting is effectively performed.
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The ______ interface is used when you want a task to return a value after execution in a thread.

  • Callable
  • Executable
  • Runnable
  • Threadable
In Java, the Callable interface is used when you want a task to return a value after its execution in a separate thread. It's similar to the Runnable interface but allows for a return value.
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Imagine you are developing a real-time multiplayer online game where player data needs to be synchronized. What strategy and technology would you choose for networking communication?

  • Use TCP with WebSockets for reliable and bidirectional communication.
  • Use UDP with WebSockets for low latency and real-time updates.
  • Use TCP with Sockets for simplicity and ease of implementation.
  • Use UDP with Sockets for minimal overhead and high throughput.
For a real-time multiplayer game, a combination of TCP and WebSockets is a robust choice. TCP provides reliability, ensuring that player data is accurately synchronized. WebSockets, built on top of TCP, add bidirectional communication for real-time updates. This approach balances reliability and real-time responsiveness. UDP with WebSockets (Option 2) may sacrifice reliability for low latency, which can lead to data loss. Using just TCP with Sockets (Option 3) may not provide the required real-time capabilities, and UDP with Sockets (Option 4) lacks the reliability needed for game synchronization.
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