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As yet another example, consider the Pattern class that finds extensive use in performing regular expression related tasks. In Java, a given String literal used for pattern matching is compiled into an instance of the Pattern type. If the pattern to be matched contains an undesired escape sequence such as a '\n', to avoid it being interpreted by the Java bytecode compiler as an escape sequence, the Pattern class requires the literal to be preceded by a backslash (":
| Code Block |
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'\\n' |
", which now correctly denotes back references instead of a new line).
In general, for a particular escape character of the form '\X', the equivalent Java representation is:
| Code Block |
|---|
" |
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\\X" |
. As an aside, this particular condition gains remarkable importance in automatic exploit signature detection systems and filters that rely on patter matching.
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