Identifiers (The Java EE 5 Tutorial)

The Java EE 5 Tutorial

Identifiers

An identifier is a sequence of one or more characters. The first character must be a valid first character (letter, $, _) in an identifier of the Java programming language (hereafter in this chapter called simply “Java”). Each subsequent character in the sequence must be a valid non-first character (letter, digit, $, _) in a Java identifier. (For details, see the Java SE API documentation of the isJavaIdentifierStart and isJavaIdentifierPart methods of the Character class.) The question mark (?) is a reserved character in the query language and cannot be used in an identifier.

A query language identifier is case-sensitive with two exceptions:

Keywords
Identification variables

An identifier cannot be the same as a query language keyword. Here is a list of query language keywords:

ALL

AND

ANY

AS

ASC

AVG

BETWEEN

BY

COUNT

CURRENT_DATE

CURRENT_TIME

CURRENT_TIMESTAMP

DELETE

DESC

DISTINCT

EMPTY

EXISTS

FALSE

FETCH

FROM

GROUP

HAVING

IN

INNER

IS

JOIN

LEFT

LIKE

MAX

MEMBER

MIN

MOD

NEW

NOT

NULL

OBJECT

OF

OUTER

OR

ORDER

SELECT

SOME

SUM

TRIM

TRUE

UNKNOWN

UPDATE

UPPER

WHERE

It is not recommended that you use a SQL keyword as an identifier, because the list of keywords may expand to include other reserved SQL words in the future.