turning my AES 128 to AES 256

Question

I copied this code from here and modified it, but then as I've read along AES I've noticed that this is using 128 since the number of key characters are only 16, now how do I make it so that it will be AES 256, though I've also read somewhere that java does not primarily allow AES 256 and only limits to AES 128, and that you need to do some more configuration for it to happen, but I am not that sure if what he said there was true and if how do I proceed with those changes. This is also my first time handling AES.

import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import javax.crypto.BadPaddingException;

import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;



public class AES {  
    private static SecretKeySpec secretKey ;
    private static byte[] key ;  
    private static String decryptedString;
    private static String encryptedString;

    public static void setKey(String myKey){ 
        MessageDigest sha = null;
        try {
                key = myKey.getBytes("UTF-8");

                sha = MessageDigest.getInstance("SHA-1");
                key = sha.digest(key);
        key = Arrays.copyOf(key, 16); // use only first 128 bit

       // System.out.println(new String(key,"UTF-8"));
            secretKey = new SecretKeySpec(key, "AES");


        } catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
        }
    }

    public static String getDecryptedString() {
        return decryptedString;
    }

    public static void setDecryptedString(String decryptedString) {
        AES.decryptedString = decryptedString;
    }

    public static String getEncryptedString() {
        return encryptedString;
    }

    public static void setEncryptedString(String encryptedString) {
        AES.encryptedString = encryptedString;
    }

    public static String encrypt(String initVector, String strToEncrypt) throws InvalidAlgorithmParameterException
    {
        try
        {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
            cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);


            setEncryptedString(Base64.encodeBase64String(cipher.doFinal(strToEncrypt.getBytes("UTF-8"))));

        }
        catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | UnsupportedEncodingException | IllegalBlockSizeException | BadPaddingException e)
        {

            System.out.println("Error while encrypting: "+e.toString());
        }
        return null;

    }

    public static String decrypt(String initVector, String strToDecrypt) throws InvalidAlgorithmParameterException, UnsupportedEncodingException
    {
        try
        {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
            cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);
            setDecryptedString(new String(cipher.doFinal(Base64.decodeBase64(strToDecrypt))));

        }
        catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException e)
        {

            System.out.println("Error while decrypting: "+e.toString());

        }
        return null;
    }


    public static void main(String args[]) throws InvalidAlgorithmParameterException, UnsupportedEncodingException
    {
                String initVector = "Bw/+ctBXLE4=@f9t"; // 16 bytes IV
                final String strToEncrypt = "12345657";
                final String strPssword = "ViK#@Uef$#!BZFgAUW6qZiudgoQ==";
                AES.setKey(strPssword);

                AES.encrypt(initVector, strToEncrypt.trim());

                System.out.println("String to Encrypt: " + strToEncrypt); 
                System.out.println("Encrypted: " + AES.getEncryptedString());

                final String strToDecrypt =  AES.getEncryptedString();
                AES.decrypt(initVector, strToDecrypt.trim());

                System.out.println("String To Decrypt : " + strToDecrypt);
                System.out.println("Decrypted : " + AES.getDecryptedString());



    }

}