Java에서 아래와 같은 구문으로 이용한다.

Pattern p = Pattern.compile("^REGULAR_EXPRESSION$", Pattern.CASE_INSENSITIVE); // regex, pattern
Matcher m = p.matcher(STRING);
boolean b = m.matches();

https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html

Pattern.CASE_INSENSITIVE    (?i)
Pattern.COMMENTS            (?x)
Pattern.MULTILINE           (?m)
Pattern.DOTALL              (?s)
Pattern.LITERAL             None
Pattern.UNICODE_CASE        (?u)
Pattern.UNIX_LINES          (?d)

\p{Lower}	A lower-case alphabetic character: [a-z]
\p{Upper}	An upper-case alphabetic character:[A-Z]
\p{ASCII}	All ASCII:[\x00-\x7F]
\p{Alpha}	An alphabetic character:[\p{Lower}\p{Upper}]
\p{Digit}	A decimal digit: [0-9]
\p{Alnum}	An alphanumeric character:[\p{Alpha}\p{Digit}]
\p{Punct}	Punctuation: One of !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~
\p{Graph}	A visible character: [\p{Alnum}\p{Punct}]
\p{Print}	A printable character: [\p{Graph}\x20]
\p{Blank}	A space or a tab: [ \t]
\p{Cntrl}	A control character: [\x00-\x1F\x7F]
\p{XDigit}	A hexadecimal digit: [0-9a-fA-F]
\p{Space}	A whitespace character: [ \t\n\x0B\f\r]

^(02|0[3-6]{1}[1-5]{1})-?[0-9]{3,4}-?[0-9]{4}$ //지역번호-xxx(x)-xxxx
^(15(44|77|88|99)|1644)-?[0-9]{4}$ //15xx/1644-xxxx

String str = "(int a, int b)";

Pattern p = Pattern.compile("\\((.*?)\\)");
Matcher m = p.matcher(str);

while(m.find())
	System.out.println(m.group(1));