The char data type in Java

A char is a single character, that is a letter, a digit, a punctuation mark, a tab, a space or something similar. A char literal is a single one character enclosed in single quote marks like this
char myCharacter = 'g';
Some characters are hard to type. For these Java provides escape sequences. This is a backslash followed by an alphanumeric code. For instance '\n' is the newline character. '\t' is the tab character. '\\' is the backslash itself. The following escape sequences are defined:

\b	backspace
\t	tab
\n	linefeed
\f	formfeed
\r	carriage return
\"	double quote, "
\'	single quote, '
\\	backslash, \

The double quote escape sequence is used mainly inside strings where it would otherwise terminate the string. For instance

System.out.println("And then Jim said, \"Who's at the door?\"");

It isn't necessary to escape the double quote inside single quotes. The following line is legal in Java

char doublequote = '"';

Further java also supports Unicode Characters.

Unicode character in java

Java uses the Unicode character set. Unicode is a two-byte character code set that has characters representing almost all characters in almost all human alphabets and writing systems around the world including English, Arabic, Chinese and more.
Unfortunately many operating systems and web browsers do not handle Unicode. For the most part Java will properly handle the input of non-Unicode characters. The first 128 characters in the Unicode character set are identical to the common ASCII character set. The second 128 characters are identical to the upper 128 characters of the ISO Latin-1 extended ASCII character set. It's the next 65,280 characters that present problems.
You can refer to a particular Unicode character by using the escape sequence \u followed by a four digit hexadecimal number. For example

\u00A9		�		The copyright symbol
\u0022		"		The double quote
\u00BD		�		The fraction 1/2
\u0394		Δ		The capital Greek letter delta
\u00F8		�		A little o with a slash through it

You can even use the full Unicode character sequence to name your variables. However chances are your text editor doesn't handle more than basic ASCII very well. You can use Unicode escape sequences instead like this:

String Mj\u00F8lner = "Hammer of Thor";

 but frankly this is way more trouble than it's worth.