Which method converts a given string to a sequence of characters?
- charAt()
- split()
- toCharArray()
- toString()
The toCharArray() method in Java's String class converts a given string into an array of characters, providing a sequence of characters. The other methods do not perform this specific task.
How does the FileWriter class handle character encoding?
- It always uses the system's default character encoding.
- It automatically detects and sets the appropriate character encoding.
- It doesn't support character encoding; it writes bytes as is.
- It prompts the user to choose the encoding when creating an instance.
The FileWriter class in Java uses the system's default character encoding for writing text to a file. It doesn't automatically detect or set character encoding. To specify a different encoding, you should use constructors like FileWriter(String fileName, Charset charset) to explicitly set the encoding.
A ________ is used to create a client socket in Java.
- DatagramSocket
- InetAddress
- ServerSocket
- Socket
In Java, to create a client socket, you use the Socket class. It allows you to establish a connection to a remote server and communicate with it. The other options represent different types of socket classes in Java but are not used for creating client sockets.
You are developing a real-time gaming application where certain operations need to be repeated at regular time intervals. Which looping mechanism and timing control statements would you use to achieve this without blocking the user interface?
- do-while loop and Thread.yield()
- for loop and System.nanoTime()
- forEach loop and System.currentTimeMillis()
- while loop and Thread.sleep()
In a real-time gaming application, you would typically use a while loop in combination with the Thread.sleep() method to introduce a delay between iterations without blocking the UI. The other options may not be suitable for achieving this specific timing control.
The ________ method of DatagramSocket class is used to send a packet to a server.
- send()
- sendPacket()
- sendToServer()
- transmitPacket()
In Java, the send() method of the DatagramSocket class is used to send a packet to a server. It is a crucial method for working with UDP (User Datagram Protocol) sockets.
What method is commonly used to execute SQL queries in Java?
- execute()
- executeQuery()
- executeStatement()
- executeUpdate()
In Java, the executeQuery() method is commonly used to execute SQL queries using JDBC. This method is specifically designed for executing SELECT queries and returns a ResultSet containing the query results. The other options (executeStatement(), executeUpdate(), and execute()) are not typically used for executing queries or have different purposes.
Imagine a situation where you are dealing with very large files that need to be read and processed, but you want to ensure that the system remains responsive and does not run out of memory. How would you implement file reading in this case?
- Read the entire file into memory using FileInputStream.
- Use a BufferedReader with a small buffer size.
- Implement a memory-mapped file using FileChannel and MappedByteBuffer.
- Use Scanner with a large buffer size.
To ensure responsiveness and prevent memory exhaustion when dealing with large files, it's best to use a BufferedReader with a reasonably small buffer size. This allows for efficient reading of the file without loading the entire content into memory. The other options are less efficient and may lead to memory issues.
The expression a != b returns true if a is ______ b.
- equal to
- greater than
- less than
- not equal to
The expression "a != b" returns true if "a" is not equal to "b." It checks if the values of "a" and "b" are different. The "!=" operator is used for inequality comparisons. The other options represent different comparison operations.
What will be the output of the following code snippet: public int add(int a, long b) { return a + b; } and public long add(int a, int b) { return a + b; }?
- Compilation Error: Ambiguous method call.
- Compilation Error: Duplicate method add with the same parameter types.
- Compilation Error: Mismatched return types.
- The code will run without errors, and the output will be the sum of a and b.
The code will result in a compilation error because both methods have the same name and the same parameter types (int and long). Java does not allow you to overload methods based solely on the return type. Overloaded methods must have different parameter lists. Overloading based on return types would lead to ambiguity.
Which of the following classes is used to create a button in JavaFX?
- Button
- CheckBox
- Label
- TextField
In JavaFX, the Button class is used to create a button. Buttons are interactive elements in a graphical user interface, and you can use the Button class to create them and add event handlers. The other classes mentioned are used for different purposes.