Explain Identifiers in Java ?

Identifiers are the names of variables, classes, methods, packages and interfaces. Unlike literals they are not the things themselves, only ways of referring to them. In the HelloWorld program, HelloWorld, String, args, main and println are identifiers.

Identifiers must be calm of letters, numbers, the underscore _ and the dollar sign $. Identifiers might only starts along with a letter, the underscore or a dollar sign.

Each variable has a name through that it is identified in the program. It's a good idea to provide your variables mnemonic names which are closely associated to the values they hold. Variable names can involve any alphabetic character or digit and the underscore _. The main restriction on the names you can provide your variables is in which they cannot contain any white space. You cannot start a variable name along with a number. It is significant to note that as in C but not as in Fortran or Basic, all variable names are case-sensitive. MyVariable is not the similar as myVariable. There is no limit to the length of a Java variable name. The subsequent are legal variable names:

• MyVariable
• myvariable
• MYVARIABLE
• x
• i
• _myvariable
• $myvariable
• _9pins
• andros
• ανδρος
• OReilly
This_is_an_insanely_long_variable_name_that_just_keeps_going_and_going_and_going_and_well_you_get_the_idea_The_line_breaks_arent_really_part_of_the_variable_name_Its_just_that_this_variable_name_is_so_ridiculously_long_that_it_won't_fit_on_the_page_I_cant_imagine_why_you_would_need_such_a_long_variable_name_but_if_you_do_you_can_have_it
The following are not legal variable names:

• My Variable // Contains a space
• 9pins // Begins with a digit
• a+c // The plus sign is not an alphanumeric character
• testing1-2-3 // The hyphen is not an alphanumeric character
• O'Reilly // Apostrophe is not an alphanumeric character
• OReilly_&_Associates // ampersand is not an alphanumeric character