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Learn how to read empty lines in Java using BufferedReader with this easy-to-follow guide and improve your file-handling skills.
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This video is based on the question https://stackoverflow.com/q/62351952/ asked by the user 'Moon' ( https://stackoverflow.com/u/13442250/ ) and on the answer https://stackoverflow.com/a/62351975/ provided by the user 'Arvind Kumar Avinash' ( https://stackoverflow.com/u/10819573/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Properly Read Empty Lines in Java using BufferedReader

Reading data from files is a common task in Java programming. However, one might encounter a small yet frustrating problem: reading empty lines. Let's dive into the issue at hand and explore a solution that ensures all lines, including empty ones, make it into your output.

The Problem: Ignoring Empty Lines

You might have experienced a situation similar to the following: You have a text file ("Flags.txt") that contains some country names, separated by empty lines, but your Java code only outputs the names, leaving the empty lines out. Here’s the code you may have tried:

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This code snippet appears to be reading data, but if we look at the outputs:

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You will notice that the empty line intended to separate "UAE" and "United States" is missing! The output does not reflect the format of the original data, which is frustrating.

Understanding the Issue

The problem arises because the readLine() method is called twice in the loop: once in the condition check and again to actually retrieve the line. This means you are skipping every alternate call. Thus, empty lines are ignored by the program.

The Solution: Single Call Read

To properly read and include empty lines in your output, you need to call readLine() only once per iteration. Here’s how you can modify your code:

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Breaking Down the Solution

Single Read: The line line = r2.readLine() only appears once within the while loop condition, ensuring that each line, including empty ones, is read correctly.

Append To StringBuffer: The sb.append(line); method adds each line to the StringBuffer. Importantly, it will append even if the line is empty, preserving the structure of the original file.

Add New Line: Calling sb.append("\r\n"); means you are adding a new line character after every read, which is crucial to maintaining the layout of the text.

Conclusion

By making this simple tweak to your code, you can successfully read all lines, including empty ones, ensuring your output accurately reflects the contents of your text file. Always remember: when working with file I/O in Java, make sure to check your loop construct, especially how you're handling your read operations.

With these tips, you're now better equipped to handle file reading in Java. So, go ahead and try it out for yourself! You’ll soon find that managing empty lines is as simple as adjusting your code to ensure it reads effectively.