Clearing a Java String

Secret.java

import java.lang.reflect.Field;
import java.io.Console;

public class Secret {

    public static void main(String[] args) throws Exception {
        Console console = System.console();
        String secret = console.readLine("secret: ");

        System.out.println("Capture secret in heap");
        System.in.read();

        clearString(secret);

        System.out.println("Removed from heap: " + secret);
        System.in.read();
    }

    static void clearString(String s) throws Exception {
        Field stringValue = String.class.getDeclaredField("value");
        stringValue.setAccessible(true);
        char[] mem = (char[]) stringValue.get(s);
        for (int i=0; i < mem.length; i++) {
            mem[i] = 'h';
        }
    }
}