import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
public static void main(String[] argv) throws Exception {
String patternStr = "\\((\\w+)\\)";
String replaceStr = "<$1>";
Pattern pattern = Pattern.compile(patternStr);
CharSequence inputStr = "a (b c) d (ef) g";
Matcher matcher = pattern.matcher(inputStr);
String output = matcher.replaceAll(replaceStr);
}
}