Here you can find the source of getHashString()
static String getHashString()
//package com.java2s; //License from project: Open Source License import java.security.SecureRandom; public class Main { static SecureRandom hashGenerator = new SecureRandom(); static String getHashString() { long hashLong; synchronized (hashGenerator) { hashLong = hashGenerator.nextLong() & 0x7FFFFFFFFFFFFFFFL; }// www. j ava2 s .c o m return Long.toHexString(hashLong); } }