Base64Utils vs. java.util.Base64

/**
 * A simple utility class for Base64 encoding and decoding.
 *
 * <p>Adapts to Java 8's {@link java.util.Base64} in a convenience fashion.
 *
 * @author Juergen Hoeller
 * @author Gary Russell
 * @since 4.1
 * @see java.util.Base64
 */
public abstract class Base64Utils {
  ...
}

/**
 * Base64-encode the given byte array.
 * @param src the original byte array
 * @return the encoded byte array
 */
public static byte[] encode(byte[] src) {
  if (src.length == 0) {
    return src;
  }
  return Base64.getEncoder().encode(src);
}

/**
 * Base64-decode the given byte array.
 * @param src the encoded byte array
 * @return the original byte array
 */
public static byte[] decode(byte[] src) {
  if (src.length == 0) {
    return src;
  }
  return Base64.getDecoder().decode(src);
}

/**
 * Base64-encode the given byte array using the RFC 4648
 * "URL and Filename Safe Alphabet".
 * @param src the original byte array
 * @return the encoded byte array
 * @since 4.2.4
 */
public static byte[] encodeUrlSafe(byte[] src) {
  if (src.length == 0) {
    return src;
  }
  return Base64.getUrlEncoder().encode(src);
}

/**
 * Base64-decode the given byte array using the RFC 4648
 * "URL and Filename Safe Alphabet".
 * @param src the encoded byte array
 * @return the original byte array
 * @since 4.2.4
 */
public static byte[] decodeUrlSafe(byte[] src) {
  if (src.length == 0) {
    return src;
  }
  return Base64.getUrlDecoder().decode(src);
}