How to insert a new line character in a String?

Hi,

Please check the below snippet.

String problemNotes = new String();

problemNotes = "Date: "+childElement.getAttributeValue("date")+"\n"+"Submitter: "+childElement.getAttributeValue("submitter")+"\n"+"Notes: "+childElement.getText();

But i am not getting a new line at all.

Please help.
[ July 10, 2008: Message edited by: Shiaber Shaam ]

There are new line characters inside the String as you expected. See this modified snippet.

import java.util.Date; public class Snippet { public static void main(String[] args) { String problemNotes = new String(); problemNotes = "Date: "+new Date() +"\n"+"Submitter: "+ "submitter" +"\n"+"Notes: "+"some notes"; System.out.println(problemNotes); } }

produced

Date: Thu Jul 10 10:00:25 PDT 2008 Submitter: submitter Notes: some notes

Unless you are writing your String to a text file and you are a Windows user. Then the new line character depends on your OS (\n for Unix, \r\n for Windows and \r for old Macs) and you should use:

String eol = System.getProperty("line.separator"); problemNotes = "Date: " + childElement.getAttributeValue("date") + eol + "Submitter: " + childElement.getAttributeValue("submitter") + eol + "Notes: " + childElement.getText();
[ July 10, 2008: Message edited by: Rodrigo Tomita ]

This is an old thread, but I don't understand why Shiaber Shaam is not getting the expected new line in his output. Can anyone explain this? Thanks.

As Rodrigo said above, each OS has it's own "New line" character. You should use System.getProperty("line.separator") to automatically get the appropriate line separator. The "\n" he is using probably isn't working because he is running his app. on a Windows system.

I have similar problem.
I am trying to read some text from .ini file and display it on JOptionPane confirm dialog. Here is the text in .ini file:

setupowngame=1. Choose settings\r\n2. Click APPLY\n3. Click on empty fields to set up archers\nLeft click to put archer on field,\nright click to put archer out of board.\nMiddle click or space to mark archer.

I supposed that each part of text will be placed in another line. But I was wrong. Whole string is in single line.


Surprisingly, I receive the same effect when I put string on stdout by System.out.println().
Here is the code:

System.out.println(language.getValue("UI", "setupowngame") + "\n" + "sometext"); ret = JOptionPane.showConfirmDialog(this, language.getValue("UI", "setupowngame") , language.getValue("UI", "infoowngame"), JOptionPane.PLAIN_MESSAGE);

Of course "sometext" appears in new line on console. How can I fix it?

Edit:
Ok I get it. I should use html.
http://docs.oracle.com/javase/tutorial/uiswing/components/html.html

There is something wrong with that file you are reading, having \r\n in places and \n elsewhere. It looks as if it has been half written in Windows® and hal in Linux.
Try
String.format("This is a String%n%s is brilliant%n", name);
Or similar
Your \n worked on a JOptionPane dialogue on my Linux box.

Shiaber Shaam wrote:Hi,

Please check the below snippet.

String problemNotes = new String();

problemNotes = "Date: "+childElement.getAttributeValue("date")+"\n"+"Submitter: "+childElement.getAttributeValue("submitter")+"\n"+"Notes: "+childElement.getText();

But i am not getting a new line at all.

Please help.
[ July 10, 2008: Message edited by: Shiaber Shaam ]

I'm not that knowledgeable about the topic but to get familiar with it, I did some browsing. I hope the reference below will guide us a bit.

Reference : https://www.wyzant.com/resources/blogs/266636/embedding_line_breaks_in_java_literal_strings

A new line character can be inserted in a string by using an escape sequence. The most commonly used escape sequence for a new line is \n. When \n is placed inside a string, it indicates that the text following it should start on a new line. This is widely supported in programming languages such as C, C++, Java, Python, and JavaScript. For example, when a string contains "Hello\nWorld", the output will display “Hello” on one line and “World” on the next line. In some systems, especially Windows, a combination of \r\n is used to represent a new line.

Welcome to the Ranch

Kamalika Seenivasan wrote:A new line character can be inserted in a string . . .

Where did you get that from? You cannot insert anything into a String that wasn't there from the beginning, because Strings are immutable. You would have to include the \n when the String was first created. If you want to insert something, it is probably best to use a StringBuilder object. As people have said, the behaviour is platform‑dependent, which is why I don't like to use plain simple \n and \r. It is probably also not strictly defined, which means that it might have changed in the 17½ years since this thread was started.

Campbell Ritchie wrote:You would have to include the \n when the String was first created.

Which of course is exactly what the original poster was talking about, along with everyone else including KS, who you are replying to.  The word "insert" was a bit misleading, but I thought the intent was clear.  "A new line character can be inserted in a string" is just a shorter way of saying "A String may be created which contains a new line character."  But it's clear from the rest of the post that they're talking about the same thing.

Different systems use different newline formats:
Linux / Mac  :  \n
Windows  : \r\n
So sometimes only \n may not behave as expected depending on where you print.
Instead of using \n use System.lineSeparator()
Example :
String problemNotes =
   "Date: " + childElement.getAttributeValue("date") + System.lineSeparator() +
   "Submitter: " + childElement.getAttributeValue("submitter") + System.lineSeparator() +
   "Notes: " + childElement.getText();

I would prefer to use String#format().String problemNotes =        String.format("Date: %s%nSubmitter: %s%nNotes: %s",               new Date(), submitter, some notes)";That will work provided the variable names both point to objects. I wouldn't touch the Date class with a bargepole. You can find more information about %n in the Formatter documentation.

Personally, I'm not a big proponent of newlines in Strings. I'd rather have separate strings and only do the newline thing when I'm actually outputting them.

Failing that, the '\n' is perfectly cromulent. I would NOT put OS-dependent line terminators (such as CR-LF) in Strings. That is something that should only be done for outputting them and I should note that in many of the Java I/O classes, the output class itself with emit the appropriate OS-specific line terminators when a newline is to be output.

By using the newline character universally, you can make code simpler and more OS-independent in much the same way you can by using Java's universal pathname syntax, which uses forward (real) slashes as opposed to OS quirks like backslashes (Windows), colons (I think this was done in early MacOS) or other more exotic platforms (for example, the Prime minicomputers used ">" as directory separators).

Tim Holloway wrote:. . . I would NOT put OS-dependent line terminators (such as CR-LF) in Strings. . . .

Nor would I, unless somebody tells me they want CR‑LF and they want me to tell them what line end I am using.
Note that the String Block construct defaults to adding plain simple \n (=LF) at the ends of lines.

Just to be pedantic here, the '\n' character should always be read as "newline". It shares the same ASCII/ASCIIZ/Unicode value as the hardware linefeed character, but it's a logical control character, not a device control character.

The reason why DOS/Windows uses CR/LF as line terminators comes from the fact that a common pre-IBM PC terminal device was a recycled Teletype[TM} machine and in order to print a new line properly, you had to send a control character to return the type carrier to column 1 and a linefeed to advance the paper. It would be equally functional to send LF/CR, and some did, but the convention became CR/LF to the point that you'd probably break some DOS programs doing a LF/CR.

Unix didn't have this issue, since it expected its device drivers to have the wit to take a hint and put out both characters when needed. Also, back when disk was expensive, a 1-character line terminator was more efficient than a 2-character terminator.

I got the impression that at one time, Apple had been using CR without LF as a line terminator. But I never encountered any such instances myself.

Of course, when dealing with Java, it's never a bad idea to ask What Would Unix Do? They'd use newline, of course.

Tim Holloway wrote:. . . a recycled Teletype[TM} machine . . .

Don't remind me of that dreadful machine

one time, Apple had been using CR without LF as a line terminator. . . .

That is correct; I think they changed to plain simple LF when they introduced OS/X.

In Java, \n is the correct newline escape sequence. If you are not seeing a line break, the issue is usually not the string, but where or how the string is being displayed.
Let’s analyze this properly.
1️⃣ Your Code is Correct
Java
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String problemNotes = "";

problemNotes = "Date: " + childElement.getAttributeValue("date") + "\n"
            + "Submitter: " + childElement.getAttributeValue("submitter") + "\n"
            + "Notes: " + childElement.getText();
This correctly inserts newline characters.
If you print it using:
Java
Copy code
System.out.println(problemNotes);
You will get new lines.
2️⃣ Why You Might Not See New Lines
✅ Case 1: Displaying in HTML (Very Common)
If you're displaying this string in:
JSP
Servlet response
Web page
HTML email
Browser
HTML ignores \n.
✔ Solution for HTML:
Use <br> instead of \n:
Java
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problemNotes = "Date: " + childElement.getAttributeValue("date") + "<br>"
            + "Submitter: " + childElement.getAttributeValue("submitter") + "<br>"
            + "Notes: " + childElement.getText();
OR wrap inside <pre>:
HTML
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<pre><%= problemNotes %></pre>
✅ Case 2: Writing to File on Windows
Windows expects:
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\r\n
So use:
Java
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System.lineSeparator()
Best practice:
Java
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String nl = System.lineSeparator();

problemNotes = "Date: " + childElement.getAttributeValue("date") + nl
            + "Submitter: " + childElement.getAttributeValue("submitter") + nl
            + "Notes: " + childElement.getText();
This works correctly on:
Windows
Linux
Mac
✅ Case 3: Showing Inside Swing / GUI Component
If you're displaying in:
JLabel → It does NOT support \n
JTextArea → It DOES support \n
For JLabel, use HTML:
Java
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label.setText("<html>Date: ...<br>Submitter: ...<br>Notes: ...</html>");
3️⃣ Best Practice Recommendation
For Java applications:
Java
Copy code
String nl = System.lineSeparator();

String problemNotes =
   "Date: " + childElement.getAttributeValue("date") + nl +
   "Submitter: " + childElement.getAttributeValue("submitter") + nl +
   "Notes: " + childElement.getText();

Vaeshnavi Subbiah wrote:. . . \n is the correct newline escape sequence. . . .

No, there is no such thing as the correct newline character. Nor is there a character called “new line.” That is the “linefeed” character, often called LF. You read \n in code (as Tim H said) as, “newline.”
We have seen already that different operating systems use different line ends. Fortunately most programs nowadays are able to use LF on its own, so there is usually no problem visible to the end‑luser.

Campbell Ritchie wrote:

Vaeshnavi Subbiah wrote:. . . \n is the correct newline escape sequence. . . .

No, there is no such thing as the correct newline character. Nor is there a character called “new line.” That is the “linefeed” character, often called LF. You read \n in code (as Tim H said) as, “newline.”
We have seen already that different operating systems use different line ends. Fortunately most programs nowadays are able to use LF on its own, so there is usually no problem visible to the end‑luser.

I must object.

You are conflating the logical end-of-line character (newline) with physical end-of-line characters such as CR/LF.

Let me take this one step further. On an IBM mainframe, traditionally text files did not contain any character at all to terminate the lines. Instead variable-length records were used.

The newline character is the universal logical line terminator for Java and the Unix operating system and its relatives. That is what applications should be using as line termination, Physical control characters do not normally appear in application program logic (excluding selected system utilities) because the OS dealt with the necessary translations at the device level using things like termcaps. The fact that MS-DOS worked with physical control characters directly is more an indication of its nature as a "collection of device drivers" (as one commentator rudely put it) as opposed to a full OS.

Again, just because the newline logical character code has the same value as the physical linefeed character code does not mean that they are the same thing.