import java.util.regex.Matcher;

import java.util.regex.Pattern;

import com.sun.org.apache.xerces.internal.impl.xpath.regex.CaseInsensitiveMap;

public class test {

    public static void main(String[] args) {

        String str = "java JavA ABC";

        Pattern test_ = Pattern.compile("java",Pattern.CASE_INSENSITIVE);

        Matcher result_ = test_.matcher(str);

        str = result_.replaceAll("Perl6");

        System.out.println(str);

    }

}