spring-session-core/src/main/java/org/springframework/session/web/http/DefaultCookieSerializer.java
private String base64Decode(String base64Value) {
		try {
			byte[] decodedCookieBytes = Base64.getDecoder().decode(base64Value);
			return new String(decodedCookieBytes);
		}
		catch (Exception ex) {
			logger.debug("Unable to Base64 decode value: " + base64Value);
			return null;
		}
	}
private String base64Decode(String base64Value) {
		try {
			byte[] decodedCookieBytes = Base64.getDecoder().decode(base64Value);
			return new String(decodedCookieBytes);
		}
		catch (Exception ex) {
			logger.debug("Unable to Base64 decode value: " + base64Value);
			return null;
		}
	}
Decode the value using Base64.
@param base64Value the Base64 String to decode
@return the Base64 decoded value
@since 1.2.2