One of the benefits of CSS-in-JS solutions is that they can prevent unused styles, leading to ________.

  • Enhanced SEO
  • Improved performance
  • Increased memory usage
  • Reduced development time
CSS-in-JS solutions, such as styled-components or Emotion, can help prevent unused styles by generating scoped styles at runtime. This means only the styles required for a specific component are injected, leading to improved performance.

You're designing a button that, when clicked, shows a loading spinner. The spinner should rotate continuously. Which properties are crucial for this effect?

  • animation-duration
    animation-timing-function
    animation-iteration-count
    animation-direction
  • box-shadow
    margin
    border-radius
    display
  • font-size
    color
    line-height
    width
  • transform
    transition
    opacity
    position
To create a loading spinner that rotates continuously, you need to use CSS animations. Key properties for this effect include animation-duration (to control the duration of the animation), animation-timing-function (to specify the timing function for animation), animation-iteration-count (to set it to 'infinite' for continuous rotation), and animation-direction (to make it rotate continuously using 'alternate' or 'normal').

In a responsive design, the term ______ is used to describe a layout that adjusts and looks good on all screen sizes.

  • adaptive
  • dynamic
  • fixed
  • fluid
In responsive design, the term "adaptive" describes a layout that adjusts and looks good on all screen sizes and devices. An adaptive design ensures that the content and layout respond effectively to various screen sizes, providing a seamless user experience.

Which of the following is a valid method to execute a stored procedure using JDBC?

  • CallableStatement.execute() with a procedure
  • executeQuery() with a stored procedure call
  • executeStoredProc()
  • executeUpdate() with a stored procedure call
To execute a stored procedure using JDBC, you typically use the CallableStatement interface and its execute() method with a procedure call. The other options (executeStoredProc(), executeQuery() with a stored procedure call, and executeUpdate() with a stored procedure call) are not standard methods for executing stored procedures in JDBC.

Which operator can be used to invert the sign of a numeric expression?

  • !
  • +
  • -
  • ~
The - (minus) operator can be used to invert the sign of a numeric expression. For example, if you have a variable int x = 5;, then -x would give you -5. The other options are not used for inverting the sign of numeric values.

How can you read data from a URL using Java?

  • Use the InputStream class
  • Use the Scanner class
  • Use the URLConnection class
  • Use the readData() method
To read data from a URL in Java, you typically use the URLConnection class to open a connection to the URL and then use the InputStream class to read the data. The other options are not standard methods for reading data from a URL.

Which of the following primitive data types has the largest size in memory?

  • byte
  • double
  • long
  • short
Among the primitive data types listed, double has the largest size in memory. It is a 64-bit data type and can store large floating-point numbers with precision. The other options (byte, short, long) have smaller memory footprints.

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.

Imagine you are developing a multi-threaded application for a bank. How would you ensure that when multiple threads are trying to update the same account, the account data remains consistent?

  • Employing optimistic locking techniques such as versioning, where each thread checks a version number before updating the account.
  • Implementing thread-safe data structures like ConcurrentHashMap to store account information.
  • Using synchronized methods or blocks to lock access to the account data when it's being updated.
  • Utilizing atomic operations provided by classes like AtomicInteger to ensure atomic updates of account data.
In a multi-threaded bank application, consistency can be achieved by using synchronized methods or blocks to ensure that only one thread can access and update the account data at a time. This prevents race conditions and data corruption. Other options, like using thread-safe data structures or atomic operations, can help with performance but may not guarantee consistency in complex scenarios. Optimistic locking with versioning can also be used to handle concurrent updates.

You need to perform different actions on each element of a heterogeneous list (i.e., containing different types of objects). How would you implement the loop to handle different types and perform type-specific actions?

  • Use a custom iterator with type-specific handlers.
  • Use a for-each loop with instanceof checks.
  • Use a series of if statements to check each element's type.
  • Use a switch statement inside a for loop.
To handle different types in a heterogeneous list, you can use a for-each loop and check each element's type using the instanceof operator. This approach allows you to perform type-specific actions. The other options may not be as flexible or efficient for this task.

How can transactions be managed in JDBC to ensure data integrity?

  • By using Connection.setAutoCommit(false) and manually committing transactions using Connection.commit()
  • By using Connection.setAutoCommit(true) and allowing transactions to automatically commit on every SQL statement execution
  • By using Connection.setReadOnly(true) to prevent any data modification, thus ensuring data integrity
  • By using Connection.setTransactionIsolation() to set the desired isolation level, ensuring data consistency
In JDBC, transactions can be managed by setting auto-commit to false using Connection.setAutoCommit(false). This allows you to manually commit transactions using Connection.commit(). This approach ensures data integrity by allowing you to group multiple SQL statements into a single transaction and ensuring that they are either all executed or none at all. Setting auto-commit to true (option 2) will not provide the same level of control over transactions. Options 3 and 4 are unrelated to managing transactions in this context.

Which of the following classes is mainly used to establish a connection to the database in JDBC?

  • java.sql.Connection
  • java.sql.DriverManager
  • java.sql.ResultSet
  • java.sql.Statement
The java.sql.DriverManager class in JDBC is primarily used for establishing database connections. It provides methods like getConnection to create connections to a database server. The other classes mentioned (Connection, Statement, and ResultSet) are used after the connection is established for various database operations.