カッコで囲まれている文字の取得

String regex = "\\((.+?)\\)";//正規表現で指定
String target = "(abc)def(ghi)jkl";
List<String> omaewamoshindeiru = new ArrayList<String>();
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(target);
while (matcher.find()) {
    omaewamoshindeiru.add(matcher.group(1));
}
System.out.println( omaewamoshindeiru.get(0) );//abc