Java Reference
In-Depth Information
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1. Lexical Issues
This section concerns the
lexical structure
of Java programs: the tokens that make up programs and
the characters that make up tokens.
1.1. The letter
el
looks like the digit 1 in many fonts
Prescription:
In long literals, always use a capital
el
(
L
), never a lowercase
el
(
l
). Do not use a lone
el
(
l
) as a variable name.
References:
Puzzle 4
.
1.2. Negative hex literals appear positive
Prescription:
Avoid mixed-type computation; use
long
literals instead of
int
literals where
appropriate.
References:
Puzzle 5
; [JLS 3.10.1].
1.3. Octal literals look like decimal literals
Prescription:
Avoid octal literals. If you must use them, comment all uses to make your intentions
clear.
References:
Puzzle 59
; [JLS 3.10.1].
1.4. Unicode escapes for ASCII characters are confusing
Prescription:
Don't use Unicode escapes for ASCII characters. Where possible, use ASCII
character directly. In string literals and character literals, prefer escape sequences to Unicode
escapes.
References:
Puzzles 14
,
16
, and
17
; [JLS 3.2, 3.3].
1.5. Backslashes must be escaped, even in comments
Prescription:
If you are writing a system that generates Java source code, escape backslashes in
generated character literals, string literals, and comments. Windows filenames are a common
source of trouble.
References:
Puzzles 15
and
16
; [JLS 3.3].
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