Java At times we need to create a one way hash(digest) for a give string/text, there are various algorithm that can be used to do so (MD5,SHA etc.) The snippet below shows how this can be done.
package com.livrona.snippets.security;

import java.math.BigInteger;
import java.security.MessageDigest;

/**
 * This snippet shows how we can generate the digest MD5 
 * for a given string. The digest is a one way hash and 
 * is represented into hex.
 * 
 * @author mvohra
 */
public class MD5Generator {
	public static void main(String args[]) throws Exception {
		// string to be encoded
		String text = "Hello World";

		// get the instances for a given digest scheme MD5 or SHA
		MessageDigest m = MessageDigest.getInstance("MD5");

		// generate the digest ; pass in the text as bytes,
		// length to the bytes(offset) to be hashed; for full string 
		// pass 0 to text.length()
		m.update(text.getBytes(), 0, text.length());

		// get the String representation of hash bytes, 
		// create a big integer out of bytes
		// then convert it into hex value (16 as input to toString method)
		String digest = new BigInteger(1, m.digest()).toString(16); 
		System.out.println("MD5: " + digest);
	}
}