For example, this is how you can express Unicode characters that do not appear on the keyboard that you use to write your source code. This is the so-called escape character that represents a Tab . There are about eight such escape characters supported by Java that represent various things like Tab , Newline , Return , Backspace , etc. Rather, this is a String literal. Any one or more characters surrounded by quotation marks are interpreted by the compiler to constitute a String literal.
Any single character surrounded by apostrophes is interpreted by the compiler to be a char literal.
When confronted with such a literal, the compiler produces the numeric value that represents that character. For example, the following code fragment will cause the value 65 to be displayed because the numeric value that represents the upper-case A in the Unicode character set is 65. Unlike some other languages, such as Python, you cannot interchange quotation marks and apostrophes when creating strings. These possibilities are represented by symbolic constants in the Float and Double classes. However, no such possibility exists for the Integer class.