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1. Overview

String formatting and generating text output often comes up during programming. In many cases, there is a need to add a new line to a string to format the output.

Let’s discuss how to use newline characters.

2. Adding New Line in a String

Operating systems have special characters to denote the start of a new line. For example, in Linux, a new line is denoted by “\n”, also called a Line Feed. In Windows, a new line is denoted using “\r\n”, sometimes called a Carriage Return and Line Feed, or CRLF.

Adding a new line in Java is as simple as including “\n” or “\r” or “\r\n” at the end of our string.

2.1. Using CRLF Line-Breaks

For this example, we want to create a paragraph using two lines of text. Specifically, we want line2 to appear in a new line after line1.

For a Unix/Linux/New Mac-based OS we can use “\n”:

String line1 = "Humpty Dumpty sat on a wall.";
String line2 = "Humpty Dumpty had a great fall.";
String rhyme = line1 + "\n" + line2;

If we are on a Windows based OS, we can use “\r\n”:

rhyme = line1 + "\r\n" + line2;

For an Old Mac based OS, we can use “\r”:

rhyme = line1 + "\r" + line2;

We’ve shown three methods of adding a new line, but it’s too bad that it would be platform-dependent.

2.2. Using Platform-Independent Line Breaks

We can also use system-defined constants when we want our code to be platform independent.

For example, using System.lineSeparator() for giving a line separator:

rhyme = line1 + System.lineSeparator() + line2;

Or we could also use System.getProperty(“line.separator”):

rhyme = line1 + System.getProperty("line.separator") + line2;

3. Adding New Line in an HTML

Suppose we are creating a string which is part of an HTML page. In that case, we can add an HTML break tag <br>.

We can also use Unicode characters “& #13;” (Carriage Return) and “& #10;” (Line Feed). Although these characters work, they don’t work exactly like we might expect them to across all platforms. Instead, it is better to use <br> for line breaks.

We can also use “\n” in some HTML elements to break a line.

Overall there are three methods of breaking a line in HTML. We can decide to use one of them, depending on the HTML tag we are using.

3.1. HTML Break Tag

We can use HTML break tag <br> to break a line:

rhyme = line1 + "<br>" + line2;

The <br> tag for breaking a line, works in almost all HTML elements like <body>, <p>, <pre> etc. However, note that it does not work in the <textarea> tag.

3.2. New Line Character

We can use ‘\n’ to break a line, if text is enclosed in <pre> or <textarea> tag:

rhyme = line1 + "\n" + line2;

3.3. Unicode Characters

We can use Unicode characters “& #13;” (Carriage Return) and “& #10;” (Line Feed), to break a line. For example, in the <textarea> tag, we can use either of these:

rhyme = line1 + "&#10;" + line2;
rhyme = line1 + "&#13;" + line2;

For the <pre> tag, both of the lines below will work:

rhyme = line1 + "&#10;" + line2;
rhyme = line1 + "&#10;&#13;" + line2;

4. Conclusion

In this article, we discussed how to add new line character in a string in Java.

We also saw how to write platform-independent code for new line using System.lineSeparator() and System.getProperty(“line.separator”).

And finally, we wrapped up with how to add a newline in case we are generating HTML page.

The full implementation of this tutorial can be found over on GitHub.

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I just announced the new Spring Boot 2 material, coming in REST With Spring:


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