This is AES 128 bit This program has a static methods encrypt and decrypt with key manual configured by developer

Cryptographic.java

package com.codewithnikhil;

import java.security.*;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

import sun.misc.*;

public class Cryptographic {

    private static final String ALGORITHM = "AES";
    private static final byte[] keyValue
            = new byte[]
            {
                    'N', 'i', 'k', 'h', 'i', 'l', 'a', 's', 'h', 'a', 'a', 'a', 'k', 'a', 's', 'h'/*this should be 16 character*/
            };

    public String encrypt(String value) throws Exception {
        Key key = generateKey();
        Cipher c = Cipher.getInstance(ALGORITHM);
        c.init(Cipher.ENCRYPT_MODE, key);
        byte[] enc = c.doFinal(value.getBytes());
        String encrypted = new BASE64Encoder().encode(enc);
        return encrypted;
    }

    public String decrypt(String encrypted) throws Exception {
        Key key = generateKey();
        Cipher c = Cipher.getInstance(ALGORITHM);
        c.init(Cipher.DECRYPT_MODE, key);
        byte[] decorded = new BASE64Decoder().decodeBuffer(encrypted);
        byte[] dec = c.doFinal(decorded);
        String decrypted = new String(dec);
        return decrypted;
    }

    private Key generateKey() throws Exception {
        Key key = new SecretKeySpec(keyValue, ALGORITHM);
        return key;
    }
}