Core Java Unit 4: Exception Handling, Strings, and Files

Easy Level Questions ( 5 Marks Each)

(Bloom’s Taxonomy: Remembering, Understanding)

1.     Differentiate between an Error and an Exception in Java. Provide one example of each.

2.     What are Checked Exceptions in Java? Give two examples of checked exceptions.

3.     Explain the purpose of the try-catch block in Java exception handling.

4.     What is the StringBuffer class in Java? How does it differ from the String class in terms of mutability?

5.     List two common methods used for formatting string data in Java.

6.     What is a Stream in the context of Java File Handling? Name the two main types of streams.

7.     How do you create a new file in Java using basic file handling operations?

Moderate Level Questions ( 5 Marks Each)

(Bloom’s Taxonomy: Understanding, Applying, Analyzing)

8.     Explain the hierarchy of Exception classes in Java. Differentiate between Checked and Unchecked exceptions with suitable examples for each.

9.     Write a Java program that demonstrates how to catch and handle a NumberFormatException that occurs when trying to convert an invalid string to an integer.

10.                        Describe the advantages of using a finally block in exception handling. Provide a code snippet to illustrate its use, ensuring that a resource (e.g., a file) is closed regardless of whether an exception occurs.

11.                        Explain the process of "Creating User-Defined Exceptions" in Java. Provide a simple example of a custom exception class and demonstrate how to throw and catch it.

12.                        Compare and contrast the String and StringBuffer classes in Java. Discuss scenarios where StringBuffer (or StringBuilder) would be preferred over String.

13.                        Write a Java program to concatenate several strings efficiently using StringBuffer. Also, demonstrate how to reverse a string using StringBuffer.

14.                        Explain the format() method for string data in Java. Provide a Java code example to format a floating-point number to two decimal places and an integer with leading zeros.

15.                        Differentiate between byte streams and character streams in Java File Handling. When would you use one over the other?

16.                        Write a Java program that reads text content from a specified file named input.txt and prints it to the console. Include basic exception handling for FileNotFoundException.

17.                        Design a Java program to append new text content to an existing file named log.txt. Ensure that existing content is not overwritten.

Difficult Level Questions ( 5 Marks Each)

(Bloom’s Taxonomy: Analyzing, Evaluating, Creating)

18.                        Design and implement a Java program that simulates a simple Account class. This class should have methods for deposit(double amount) and withdraw(double amount).

o    Create a user-defined InsufficientFundsException that is thrown if a withdrawal attempt exceeds the current balance.

o    The withdraw method should declare this exception using throws.

o    Demonstrate in your main method how to call the withdraw method within a try-catch block to handle the InsufficientFundsException gracefully, printing an appropriate message.

19.                        Evaluate the efficiency and best practices when performing extensive string manipulations in Java. Compare the performance implications of using String concatenation repeatedly in a loop versus using StringBuilder or StringBuffer. Provide a conceptual analysis and suggest scenarios where each would be most appropriate.

20.                        Design a comprehensive Java program for file handling that:

o    Creates a new text file named data.txt.

o    Writes at least five lines of text, including a mix of numbers and words, into data.txt.

o    Reads the content from data.txt line by line.

o    For each line read, attempts to convert any numeric part of the line into an integer. If a NumberFormatException occurs, it should log the error to the console but continue processing.

o    Finally, counts the total number of lines and the total number of successfully parsed integers from the file, printing these statistics to the console.

o    Ensure all file operations are enclosed in try-catch-finally blocks to handle potential IOException and ensure resources are properly closed.