Escape Sequence In Java

In Java, the escape sequence is a character preceded by a backslash (\) and it has special meaning to the compiler, JVM, Console, and Editor software. Every escape character must start with \ following by a single character

The escape sequence changes the original meaning of a character. When we place \ before a character then it is not considered as a regular character some special functionality will be added. For example, if we use just ‘n’, then it is treated as a character ‘n’.

System.out.println("Know n Program");

Output:-

Know n Program

But if we place \ before ‘n’ then its meaning is changed and now its represents a new line,

System.out.println("Know \n Program");

Output:-

Know
Program

When an escape sequence is encountered in a print statement, the compiler interprets it accordingly. For example, if you want to put quotes within quotes you must use the escape sequence, \”, on the interior quotes.

Escape Character in Java

Java supports following escape characters.

Escape character	Description	Unicode value
\b	Backspace	\u0008
\t	Horizontal tab	\u0009
\n	New line	\u000a
\f	Form feed	\u000c
\r	Carriage return	\u000d
\"	Double quote	\u0022
\'	Single quote	\u0027
\\	Backslash	\u005c

Java Escape Sequence Example

The \t escape character is used to insert one tab space (generally 5 space) between the text. Example:-

System.out.println("Java\tKnow\tProgram");

Output:-

Java Know Program

Whearas \n escape character is used to insert one line between the text. Example:-

System.out.println("Java\nKnow\nProgram");

Output:-

Java
Know
Program

The \b escape character moves the cursor one character back with or without deleting the character. The output depends on the compiler.

System.out.println("Java\bKnow\bProgram");

Output:-

JavKnoProgram

The \f escape sequence is a form feed character. It is an old technique and used to indicate a page break. The output depends on the compiler.

System.out.println("Java\fKnow\fProgram");
Output:-
Java
     Know
         Program

The carriage return \r moves the output point back to the beginning of the line without moving down a line. The output depends on the compiler.

System.out.println("Java\rKnow\rProgram");
System.out.println("\rJava");
System.out.println("Java\rKnow");

Output:-

Program
Java
Know

The backslash escape character \\ is used to represent ‘\’. It contains two backslashes, this means after reading the first \ the compiler read the next \ as a new character.

System.out.println("The file is located"
             +" at C:\\KnowProgram\\Java");

Output:-

The file is located at C:\KnowProgram\Java

Simple programs

Program1:- Display ‘K’ with in single quote and double quote.

System.out.println("'K'"); // 'K'
System.out.println("\'K\'"); // 'K'

// System.out.println(""K""); // error
System.out.println("\"K\""); // "K"

Program2:- Print the following text.
She said “Hello!” to me.

It should be written as,

System.out.println("She said \"Hello!\" to me.");

Program3:- Display the following folder.
D:\Java\Program

System.out.println("D:\Java\Program"); // error
System.out.println("D:\\Java\\Program"); // valid
Output:- D:\Java\Program

New Escape characters

To support text block features two escape characters are introduced in Java15 version. These are,

Escape character	Description
\	line-terminator
\s	Insert space

A text block is a new kind of literal in the Java language. It may be used to denote a string anywhere that a string literal could appear, but offers greater expressiveness and less accidental complexity. A text block consists of zero or more content characters, enclosed by opening and closing delimiters. Example of text block:-

"""
line 1
line 2
line 3
"""

is equivalent to the string literal:

"line 1\nline 2\nline 3\n"

or a concatenation of string literals:

"line 1\n" +
"line 2\n" +
"line 3\n"

Use of line-terminator (\)

Generally, we split a long string into smaller substring and then using + operator convert them into multiple lines. Example:-

String text = "Lorem ipsum dolor sit amet, consectetur adipiscing " +
              "elit, sed do eiusmod tempor incididunt ut labore " +
              "et dolore magna aliqua.";

In text block using line-terminator is can be simply written as,

String text = """
                Lorem ipsum dolor sit amet, consectetur adipiscing \
                elit, sed do eiusmod tempor incididunt ut labore \
                et dolore magna aliqua.\
                """;

Use of \s

Escape sequences aren’t translated until after incidental space stripping, so \s can act as a fence to prevent the stripping of trailing white space. Using \s at the end of each line in this example guarantees that each line is exactly six characters long:

String colors = """
    red  \s
    green\s
    blue \s
    """;

The \s escape sequence can be used in text blocks, traditional string literals, and character literals. Learn More:- Text blocks

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