Catalog of Traps and Pitfalls - Java Puzzlers: Traps, Pitfalls, and Corner Cases - page 315

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10. Strings
This section concern character strings.
10.1. Arrays do not override Object.toString
Prescription: For char arrays, use String.valueOf to obtain the string representing the designated
sequence of characters. For other types of arrays, use Arrays.toString or, prior to release 5.0,
Arrays.asList .
References: Puzzle 12 ; [JLS 10.7].
10.2. String.replaceAll takes a regular expression as its first argument
Prescription: Ensure that the argument is a legal regular expression, or use String.replace
instead.
References: Puzzle 20 .
10.3. String.replaceAll takes a replacement string as its second
argument
Prescription: Ensure that the argument is a legal replacement string, or use String.replace
instead.
References: Puzzle 20 .
10.4. Repeated string concatenation can cause poor performance
Prescription: Avoid using the string concatenation operator in loops.
References: [EJ item 33].
10.5. Conversion of bytes to characters requires a charset
Prescription: Always select a charset when converting a byte array to a string or char array; if you
don't, the platform default charset will be used, leading to unpredictable behavior.
References: Puzzle 18 .
10.6. Values of type char are silently converted to int , not String