/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.*;
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		final String REGEX = "data|you|Us";
        final String MASK = "****";
        final Pattern PATTERN = Pattern.compile(REGEX);
        String message = "Hai man how are you ? Give me data which you have fetched as it is very important data to Us";
        Matcher matcher = PATTERN.matcher(message);        
		StringBuffer result = new StringBuffer();
		while (matcher.find()) {
    		String replacement = 
    			matcher.group(0).replaceAll(".", MASK.substring(0, 1));
		    matcher.appendReplacement(result, replacement);
		}
		matcher.appendTail(result);
		System.out.println(result.toString());
 
	}
}

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