Identifiers are symbolic names utilized for recognition. Identifiers in the Java program can be a class name, variable name, constant name, array name, methods name, and packaging name. Some examples of Java identifiers include MyVariable, x, I, my_variable, _ my variable, $myvariable, dataflair/23.
Identifiers do not contain a space, do not begin with numbers, plus sign is not an alphanumeric character. A valid identifier has characters or numbers and an underscore.
You cannot declare a variable with space. You cannot start an identifier with a number. 4-15 letters only are suitable to apply. It is not advised to use reserved words as an identifier, and reverse words can also be identifiers.