How does Java handle method overloading with autoboxing and varargs?
- Java allows method overloading, but it may lead to ambiguity.
- Java automatically selects the method based on the argument types.
- Java does not allow method overloading with autoboxing and varargs.
- The compiler throws an error due to ambiguity.
In Java, method overloading with autoboxing and varargs is allowed. However, it should be used with caution, as it can lead to ambiguity in certain cases. Java will automatically select the most specific method based on the argument types provided. This behavior allows you to use overloaded methods with autoboxing and varargs, but you should be aware of potential ambiguities.
Which of the following statements correctly creates an object of a class named 'Dog'?
- Dog dog = new Dog();
- Dog obj = createObject();
- Dog.create();
- Dog.new();
To create an object of a class named 'Dog' in Java, you should use the class name followed by the constructor using the new keyword, like this: Dog dog = new Dog();. The other options are not the correct way to create an object of a class in Java.
To write a newline character when using FileWriter, you can use ________.
- "n"
- "n"
- "r"
- 'n'
To write a newline character when using FileWriter, you can use "n". This escape sequence represents a newline character in Java and is commonly used to create line breaks in text files.
Does Java support operator overloading?
- No, not at all.
- Only for arithmetic ops.
- Yes, for all operators.
- Yes, for selected ops.
Java does not support operator overloading for custom classes. While some languages do allow operator overloading, Java enforces a fixed set of operators for built-in types, and you cannot create custom operator overloads. This limitation helps maintain code readability and prevents ambiguity.
How can we handle SQL exceptions that may occur during the execution of a JDBC program?
- Ignore them and let the program continue
- Use assert statements to handle exceptions
- Use if-else statements to handle exceptions
- Use try-catch blocks to catch and handle exceptions
SQL exceptions in a JDBC program should be handled using try-catch blocks. Ignoring them can lead to unexpected program behavior, and try-catch allows you to gracefully handle errors, log them, or take corrective actions. The other options are not recommended approaches for handling exceptions in JDBC.
To write primitive data types like int or double to a file in a machine-independent way, you might use ________.
- DataOutputStream
- FileInputStream
- ObjectInputStream
- ObjectOutputStream
To write primitive data types to a file in a machine-independent way, you can use DataOutputStream. It provides methods for writing different data types to a file while ensuring that the data can be read back correctly.
How does Java handle the division of an integer by zero?
- It returns NaN (Not-a-Number).
- It returns a positive or negative infinity value, depending on the sign of the numerator.
- It returns zero.
- It throws an ArithmeticException.
In Java, dividing an integer by zero results in an ArithmeticException being thrown at runtime. Division by zero is mathematically undefined, and Java handles it by throwing this exception to indicate the error. Options 1, 3, and 4 are incorrect because they don't accurately represent how Java handles this situation.
A JDBC ________ provides the necessary methods to interact with the database.
- Connection
- Driver
- ResultSet
- Statement
In JDBC, a Connection is used to establish a connection to a database. It provides the necessary methods to interact with the database, such as executing SQL queries and managing transactions. A JDBC Driver is responsible for establishing the connection, but the Connection object is what allows you to interact with the database.
Imagine you are working on a system that categorizes user feedback into positive, negative, and neutral based on certain keywords. Describe how you'd structure your control statements to efficiently categorize the feedback.
- Create a custom machine learning model
- Implement a decision tree algorithm
- Use if-else statements with keyword checks
- Utilize regular expressions for keyword matching
To efficiently categorize user feedback based on keywords, you can use if-else statements. For each feedback, check if it contains specific positive, negative, or neutral keywords. Regular expressions can also be helpful for more complex matching. While decision trees and machine learning models are powerful for sentiment analysis, they might be overkill for simple keyword-based categorization.
Which of the following access modifiers is allowed for a method in an interface?
- default
- private
- protected
- public
In Java interfaces, all methods are implicitly public, whether you declare them as such or not. You cannot use the private, protected, or default access modifiers for methods in an interface.