The ________ method of Throwable class can be used to retrieve the description of an exception.
- getDescription()
- getDescriptionText()
- getExceptionDescription()
- getMessage()
The getMessage() method of the Throwable class is used to retrieve the description or message associated with an exception. This message provides additional information about the exception, helping developers understand the cause of the error.
Which of the following classes is used to write characters to a file in Java?
- BufferedReader
- FileOutputStream
- FileWriter
- PrintWriter
The FileWriter class in Java is used to write characters to a file. It provides methods to write character data to a file in a character stream. FileOutputStream is used for writing binary data, PrintWriter is used for formatted text output, and BufferedReader is used for reading character data, not writing.
What happens if no constructor is provided in a Java class?
- The class cannot be instantiated, and objects of that class cannot be created.
- Java automatically provides a default no-argument constructor for the class.
- The class can only be instantiated by other classes in the same package.
- The class becomes a singleton by default.
a) is correct. If no constructor is provided in a Java class, Java automatically provides a default no-argument constructor. b) is a common misconception; Java only provides a default constructor if you haven't defined any constructors explicitly. c) and d) are incorrect statements.
The ________ method of the String class returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.
- indexOf(char ch)
- indexOf(char ch, int fromIndex)
- lastIndexOf(char ch)
- lastIndexOf(char ch, int fromIndex)
The lastIndexOf(char ch, int fromIndex) method of the String class is used to find the index of the last occurrence of the specified character within the string, starting the search from the given index fromIndex. The other options are related to the indexOf method but don't perform the same task.
Which of the following is a primitive data type in Java?
- ArrayList
- Boolean
- String
- int
In Java, primitive data types are basic data types that store single values. int is one of the primitive data types and is used to store integer values. String, ArrayList, and Boolean are not primitive data types; they are reference data types or classes.
Imagine a situation where you need to insert a large dataset (for example, 10,000 rows) into a database using JDBC. How would you optimize this process to ensure that it is done efficiently and does not consume excessive resources?
- Disable database constraints temporarily during the insertion process.
- Execute individual INSERT statements in a loop for each row in the dataset.
- Increase the database transaction isolation level to SERIALIZABLE for the insertion operation.
- Use batch processing with prepared statements to insert multiple rows in a single database call.
Batch processing with prepared statements is the most efficient way to insert a large dataset into a database using JDBC. It reduces the overhead of multiple database calls by grouping multiple insertions into a single call. Executing individual INSERT statements in a loop is resource-intensive and not recommended for large datasets. Disabling database constraints can compromise data integrity. Increasing the transaction isolation level to SERIALIZABLE is not needed for a simple insertion operation.
The collect() method in the Stream API is a type of ________ operation.
- Intermediate
- Stateful
- Stateless
- Terminal
The collect() method is a terminal operation in the Stream API. It is used to accumulate the elements of a stream into a collection, such as a List or Set. Terminal operations are those that trigger the processing of the stream and produce a final result.
In a real-world application managing user profiles, how might parameterized constructors be used to quickly initialize user objects with provided details during registration?
- Parameterized constructors are not used for user profile initialization.
- Parameterized constructors are used for data retrieval from the database.
- Parameterized constructors are used to create admin profiles with elevated privileges.
- Parameterized constructors can accept user details as parameters and create user objects with initialized data during registration.
Parameterized constructors can be utilized in a user profile management system to quickly initialize user objects during the registration process. These constructors accept user details (e.g., username, email, password) as parameters, allowing you to create user objects with pre-populated data, making registration more efficient and straightforward.
The method ________ is used to execute SQL for DDL statements using JDBC.
- executeDDL()
- executeQuery()
- executeStatement()
- executeUpdate()
In JDBC, the method executeUpdate() is used to execute SQL statements that perform Data Definition Language (DDL) operations, such as creating, altering, or dropping database objects. It returns an integer representing the number of rows affected by the statement. executeQuery() is used for retrieving data, not DDL statements.
If a class has multiple constructors, it can be said to have constructor ________.
- chaining
- overloading
- overriding
- polymorphism
When a class has multiple constructors with different parameter lists, it is said to have constructor overloading. Constructor overloading allows you to create multiple constructors in the same class, each with a different set of parameters. This is a form of method overloading specific to constructors. Constructor overriding is not a valid term in Java.