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.

To specify a repeating behavior in an animation, ______ method is used in JavaFX.

  • cycleAnimation()
  • repeatAnimation()
  • setCycleCount()
  • setRepeatCount()
In JavaFX, the setCycleCount() method is used to specify the number of times an animation should repeat. By setting the cycle count to a specific value, you can control how many times the animation should loop or repeat, creating repeating behaviors in your animations.

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.

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.

If you do not define a constructor, Java provides one default constructor that initializes all instance variables with ________.

  • null values
  • random values
  • the default values
  • zeros
When you don't define a constructor in a Java class, Java provides a default constructor. This default constructor initializes all instance variables with their default values, which can be zero for numeric types, false for booleans, and null for reference types.

What is the impact on memory usage when declaring a large two-dimensional array with most elements being zero?

  • Java allocates a separate memory block for each zero element, causing a substantial memory overhead.
  • Java automatically compresses the zero values, reducing memory usage.
  • No significant impact as Java optimizes storage for zero values using sparse array representations.
  • Significant increase in memory usage due to zero values being explicitly stored, wasting memory.
Java optimizes memory usage for large two-dimensional arrays with many zero elements by using a sparse array representation. It avoids storing explicit zero values, reducing memory consumption significantly. The other options do not reflect Java's memory optimization techniques for sparse data.

Which arithmetic operator is used to perform exponentiation in Java?

  • **
  • ^
  • ^^
  • ^^
In Java, the exponentiation operator is **. It is used to raise a number to a power. For example, 2 ** 3 would result in 8, as it calculates 2 raised to the power of 3. The other options are not used for exponentiation in Java.

Which of the following operators will determine whether two values are not equal?

  • !=
  • <>
  • ==
  • ===
In Java, the '!=' operator is used to determine whether two values are not equal. For example, x != y evaluates to true if x and y are not equal. The other options are used for equality checks (==, ===) or are not valid operators in Java (<>).

Which of the following concepts allows Java objects to be initialized with actual data when they are created?

  • Class variables
  • Constructors with parameters
  • Default constructors
  • Initialization blocks
In Java, constructors with parameters allow objects to be initialized with actual data when they are created. Default constructors are provided by the compiler and don't take parameters. Initialization blocks are used for initializing instance variables, but they don't take external data. Class variables (static fields) are not used for initializing object-specific data.

Imagine you are working on a system that heavily utilizes serialization. How would you manage a scenario where sensitive data, such as passwords, should not be serialized?

  • Encrypt the sensitive data before serialization and decrypt it after deserialization
  • Implement a custom writeObject method to exclude the sensitive data during serialization
  • Use a separate, non-serializable class to store sensitive data
  • Use the transient keyword to mark the sensitive data
The transient keyword is used to indicate that a field should not be serialized. In this scenario, marking sensitive data fields as transient ensures that they are excluded from serialization. Implementing a custom writeObject method allows fine-grained control over the serialization process. Encrypting the data is a valid approach but doesn't directly address the issue of excluding it from serialization. Using a separate class for sensitive data avoids serialization issues but is not directly related to the question.