Example: Display Own Source Code in Java

// Display Own Source Code
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

// Main class containing the entry point of the program
public class DisplaySourceCode { // Note: Class name must match file name (DisplaySourceCode.java)
    public static void main(String[] args) {
        // Step 1: Specify the name of the source file.
        // For this program to work, the Java source file must be named "DisplaySourceCode.java"
        // and be located in the directory from which the compiled .class file is executed.
        String sourceFileName = "DisplaySourceCode.java";

        // Step 2: Utilize a try-with-resources statement for efficient and safe file handling.
        // This ensures that the FileReader and BufferedReader are automatically closed
        // once the try block is exited, regardless of whether an exception occurred.
        try (BufferedReader reader = new BufferedReader(new FileReader(sourceFileName))) {
            String line;
            System.out.println("--- SOURCE CODE DISPLAY START ---");
            // Step 3: Read the file line by line until the end of the file is reached.
            while ((line = reader.readLine()) != null) {
                // Step 4: Print each line read from the source file to the console.
                System.out.println(line);
            }
            System.out.println("--- SOURCE CODE DISPLAY END ---");
        } catch (IOException e) {
            // Step 5: Catch and handle any IOException that might occur during file operations.
            // This includes scenarios like the file not being found, permissions issues, or read errors.
            System.err.println("Error: Could not read the source file '" + sourceFileName + "'.");
            System.err.println("Please ensure 'DisplaySourceCode.java' exists in the current directory.");
            System.err.println("Details: " + e.getMessage());
            // For more detailed debugging, uncomment the following line:
            // e.printStackTrace();
        }
    }
}