import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
public static void main(String args[]) {
Pattern p = Pattern.compile("(another) (test)");
StringBuffer sb = new StringBuffer();
String candidateString = "This is another test.";
String replacement = "$1 AAA $2";
Matcher matcher = p.matcher(candidateString);
matcher.find();
matcher.appendReplacement(sb, replacement);
String msg = sb.toString();
System.out.println(msg);
}
}